Migration Scenarios Research Articles

Reversal of migration flows: A fresh look at the German reunification

We investigate the dynamic effects of interregional labor market integration on migration flows, capital formation, and the price for housing services. The co-evolution of these variables depends on initial conditions at the time of labor market integration. In an initially capital-poor economy, there may be a reversal of migration flows during the transition to the steady state, while housing costs are increasing over time. Although capital may accumulate while labor emigrates early in the transition, the causal effect of immigration on capital investments and housing costs is positive. We present new data on the evolution of net migration flows and rental rates for housing in East Germany after 1990. Our results are consistent with the presented evidence in the reverse migration scenario.

A Risk Management Framework for Cloud Migration Decision Support

Keywords: risk management framework; risk assessment; cloud migration; security; analytic hierarchy process (AHP); business value

Challenges in migrating legacy software systems to the cloud — an empirical study

Moving existing legacy systems to cloud platforms is a difficult and high cost process that may involve technical and non-technical resources and challenges. There is evidence that the lack of understanding and preparedness of cloud computing migration underpin many migration failures in achieving organisations’ goals. The main goal of this article is to identify the most important challenging activities for moving legacy systems to cloud platforms from a perspective of reengineering process. Through a combination of a bottom-up and a top-down analysis, a set of common activities is derived from the extant cloud computing literature. These are expressed as a model and are validated using a population of 104 shortlisted and randomly selected domain experts from different industry sectors. We used a Web-based survey questionnaire to collect data and analysed them using SPSS Sample T-Test. The results of this study highlight the most important and critical challenges that should be addressed by various roles within a legacy to cloud migration endeavour. The study provides an overall understanding of this process including common occurring activities, concerns and recommendations. In addition, the findings of this study constitute a practical guide to conduct this transition. This guide is platform agnostic and independent from any specific migration scenario, cloud platform, or an application domain.

INTERREGIONAL MIGRATION IN BRAZIL: WHAT'S NEW?

Esse trabalho tem como principal objetivo analisar a dinâmica migratória inter-regional no Brasil, durante os quinquênios de 1986/1991, 1995/2000 e 2005/2010. Tem a intenção de identificar o que há de novo no cenário migratório brasileiro com relação às n

Identifying migration scenarios (trends, continuities and brakes) and mobility issues in the Arab Mediterranean Countries

Identifying migration scenarios (trends, continuities and brakes) and mobility issues in the Arab Mediterranean Countries

Telecommunication Numbering System Roadmap towards Next Generation Network Era in Indonesia

The telecommunication numbering system in Indonesia currently complies to the International TelecommunicationUnion (ITU) standard, that is ITU-T E.164. In accordance to both technology development and the growing of network users, ITU has also been designing future infrastructure network concept, namely Next Generation Network Infrastructure (NGNI). In its technical paper, ITU discusses future generation’s specification as well as current network migration scenarios towards Next Gereration Network (NGN) in developing countries and its impact on regulations, business processes, and the numbering system. The scenario described in the concept is yet universal and the implementation would be highly depending on the conditions of ones country. This paper proposes the roadmap of numbering system from the current state into NGN numbering for the case of Indonesia. The method used in this paper are benchmarking with several countries that have started with the transformation process, forecasting with regression method based on the existing trends and descriptive analysis. This paper has proposed the stages of numbering roadmap towards NGN numbering system, the achievement parameters, and the indicators that are suitable for Indonesia.

Modelling giant red shrimp larval dispersal in the Sardinian seas: density and connectivity scenarios

AbstractThe connectivity and three‐dimensional (3D) dispersion of the larvae of giant red shrimp, potentially released from known spawning areas along the Sardinia slope in the western Mediterranean Sea, were assessed using Lagrangian simulations forced by a 3D submesoscale permitting a regional ocean model. Biophysical simulations using the hydrodynamic conditions of the year 2012 were run to track propagules released from known spawning areas during the spawning period (May to September). Passive transport (PT) and vertical migration (VM) scenarios were tested, each with two possible pelagic larval durations (PLDs) of 21 or 42 days. Dispersion of propagules in the PT and VM scenarios differed in terms of travelled distance, export out of the domain (larger for VM), and depth distribution (shallower and bimodal for VM due to the larger variability of encountered currents). Connectivity patterns were investigated among eight release areas, and four predetermined Eco‐Regions, and results showed strong connectivity among the North‐Western (NW), Western (W), and Southern (S) regions of Sardinia, whereas the Eastern region was more segregated. Differences in connectivity patterns among scenarios were related mainly to the tendency of greater retention of propagules in the release area for the PT scenarios. This finding, together with existing hypotheses of vertical migration likely occurring during first egg‐larval phases, suggest that the VM scenarios are the most probable of the two hypotheses tested. Strong connectivity between the W and S sides of Sardinia and the relative isolation of the E side could have significant implications for the protection of this important resource.

On the formation of hot and warm Jupiters via secular high-eccentricity migration in stellar triples

Hot Jupiters (HJs) are Jupiter-like planets orbiting their host star in tight orbits of a few days. They are commonly believed not to have formed in situ, requiring inwards migration towards the host star. One of the proposed migration scenarios is secular high-eccentricity or high-$e$ migration, in which the orbit of the planet is perturbed to high eccentricity by secular processes, triggering strong tidal evolution and orbital migration. Previous theoretical studies have considered secular excitation in stellar binaries. Recently, a number of HJs have been observed in stellar triple systems. In the latter, the secular dynamics are much richer compared to stellar binaries, and HJs could potentially be formed more efficiently. Here, we investigate this possibility by modeling the secular dynamical and tidal evolution of planets in two hierarchical configurations in stellar triple systems. We find that the HJ formation efficiency is higher compared to stellar binaries, but only by at most a few tens of per cent. The orbital properties of the HJs formed in the simulations are very similar to HJs formed in stellar binaries, and similarly to studies of the latter we find no significant number of warm Jupiters. HJs are only formed in our simulations for triples with specific orbital configurations, and our constraints are approximately consistent with current observations. In future, this allows to rule out high-$e$ migration in stellar triples if a HJ is detected in a triple grossly violating these constraints.

Using logic programming for adapting models to metamodel evolution

Evolution is inherent in software systems because of the rapid improvement of technologies. As metamodels are the cornerstone of model driven engineering and they evolve iteratively, their evolution affects the rest of artefacts involved in a development process, e.g., models or transformation rules. Therefore, co-evolution tools for models and other artefacts are indispensable. We present in this paper an intelligent approach to adapt models by means of state-based and operator-based techniques. The defined co-evolution process consists of four phases. Initially, changes between two metamodel versions are detected. After that, evolution scenario is reconstructed using logic programming method. Evolution scenario is first calculated from difference model and represented by a set of primitive evolution operations, after that it is transformed using an inference engine to include eventual composite evolution operations; from this scenario adaptation solutions are generated according to the evolution operator impact in model level. Finally, migration scenario is applied on an input model conforming to the old metamodel version to remain compliant with its metamodel.

Efficient public auditing for data migration across cloud systems

Cloud storage has gained great attention in recent years. It brings many benefits as well as security issues. Cloud auditing technology can ensure the integrity of cloud users' data. However, it lacks efficiency when dealing with the migration scenario of a large amount of cloud data. In this paper, we propose an efficient cloud auditing scheme which supports data migration auditing. We first construct a privacy-preserving auditing scheme that can audit cloud data during data migration, which can hugely reduce the migration cost when data corruption happens. We further extend the scheme to support data update during auditing. By supporting batch auditing for multiple cloud users' migration auditing tasks, our scheme could hugely improve the efficiency. Performance analysis demonstrates that our auditing scheme is secure and efficient.

DYNAMICAL CONSTRAINTS ON THE ORIGIN OF HOT AND WARM JUPITERS WITH CLOSE FRIENDS

ABSTRACT Gas giants orbiting their host star within the ice line are thought to have migrated to their current locations from farther out. Here we consider the origin and dynamical evolution of observed Jupiters, focusing on hot and warm Jupiters with outer friends. We show that the majority of the observed Jupiter pairs (20 out of 24) are dynamically unstable if the inner planet is placed at ≳1 au distance from the stellar host. This finding is at odds with formation theories that invoke the migration of such planets from semimajor axes ≳1 au due to secular dynamical processes (e.g., secular chaos, Lidov–Kozai [LK] oscillations) coupled with tidal dissipation. In fact, the results of N-body integrations show that the evolution of dynamically unstable systems does not lead to tidal migration but rather to planet ejections and collisions with the host star. This and other arguments lead us to suggest that most of the observed planets with a companion could not have been transported from farther out through secular migration processes. More generally, by using a combination of numerical and analytic techniques, we show that the high-e LK migration scenario can only account for less than 10% of all gas giants observed between 0.1 and 1 au. Simulations of multiplanet systems support this result. Our study indicates that rather than starting on highly eccentric orbits with orbital periods above 1 yr, these “warm” Jupiters are more likely to have reached the region where they are observed today without having experienced significant tidal dissipation.

The origin and 9:7 MMR dynamics of the Kepler-29 system

We analyse the Transit Timing Variation (TTV) measurements of a~system of two super-Earths detected as Kepler-29, in order to constrain the planets' masses and orbital parameters. A dynamical analysis of the best-fitting configurations constrains the masses to be $\sim 6$ and $\sim 5$ Earth masses for the inner and the outer planets, respectively. The analysis also reveals that the system is likely locked in the 9:7~mean motion resonance. However, a variety of orbital architectures regarding eccentricities and the relative orientation of orbits is permitted by the observations as well as by stability constraints. We attempt to find configurations preferred by the planet formation scenarios as an additional, physical constraint. We show that configurations with low eccentricities and anti-aligned apsidal lines of the orbits are a natural and most likely outcome of the convergent migration. However, we show that librations of the critical angles are not necessary for the Kepler-29 system to be dynamically resonant, and such configurations may be formed on the way of migration as well. We argue, on the other hand, that aligned configurations with $e \gtrsim 0.03$ may be not consistent with the migration scenario.

Injection risk assessment for intra‐formational seal geological model in a carbon sequestration application in Taiwan

AbstractAs a deep saline aquifer, the Tai‐hsi Foreland Basin in western Taiwan is regarded as an excellent locality to sequester the huge carbon emission from domestic coal‐fired power plants. Existing geological data show that an intra‐formational seal capability characterized by multilayered shale baffles can act as the primary or ultimate cap system. In this study, the relevant ranges of rock parameter of porosity (20∼35%) and permeability (0.0001∼1300 mD), respectively, for the storage layers (sandstone) and seals (shale) have been selected according to large amount of laboratory core test from a nearby pioneering 3000 m drilling and sampling within the southern flank of the Tai‐hsi Basin. Comprehensive geological models considering both homogeneous and heterogeneous cases, and a typical plume migration scenario under a single‐well injection were simulated under a 20‐year continuous injection (1 MtCO2 per year) followed by post‐injection monitoring up to 1000 years. Corresponding 2D maximum horizontal migration distances (MHMD) of CO2 plume in the storage reservoir were calculated with respect to a homogeneous reservoir model and its heterogeneous counterparts. In addition, the induced pressures at critical monitoring points were also evaluated and compared. As a consequence, the ubiquitous shale baffles of intra‐formational seal in a heterogeneous saline aquifers were proven to be a successful trapping mechanism controlling the migration distances of lateral and upward movement. Furthermore, safe carbon storage operation within Tai‐hsi Basin with formation depth range about 2135 to 2450 mRT can be ensured by checking statistically the calculated maximum MHMD and the induced pressure magnitude. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd.

The Impact of Possible Migration Scenarios after ‘Brexit’ on the State Pension System

The purpose of this paper is to explore the impacts of changes in migration flows—in particular, those resulting from possible migration policy changes after a UK exit (‘Brexit’) from the European Union (EU)—on the finances of the UK state pension system. We find that the aggregate effects of considered shocks to immigration associated with Brexit on the funding of UK state pensions are dwarfed by associated uncertainties, and by coincident cost increases due to population aging and (domestic) pension’s policy.

TRACKING NEPTUNE’S MIGRATION HISTORY THROUGH HIGH-PERIHELION RESONANT TRANS-NEPTUNIAN OBJECTS

ABSTRACT Recently, Sheppard et al. presented the discovery of seven new trans-Neptunian objects with moderate eccentricities, perihelia beyond 40 au, and semimajor axes beyond 50 au. Like the few previously known objects on similar orbits, these objects’ semimajor axes are just beyond the Kuiper Belt edge and clustered around Neptunian mean motion resonances (MMRs). These objects likely obtained their observed orbits while trapped within MMRs, when the Kozai–Lidov mechanism raised their perihelia and weakened Neptune’s dynamical influence. Using numerical simulations that model the production of this population, we find that high-perihelion objects near Neptunian MMRs can constrain the nature and timescale of Neptune’s past orbital migration. In particular, the population near the 3:1 MMR (near 62 au) is especially useful due to its large population and short dynamical evolution timescale. If Neptune finishes migrating within ∼100 Myr or less, we predict that over 90% of high-perihelion objects near the 3:1 MMR will have semimajor axes within 1 au of each other, very near the modern resonance’s center. On the other hand, if Neptune’s migration takes ∼300 Myr, we expect ∼50% of this population to reside in dynamically fossilized orbits over ∼1 au closer to the Sun than the modern resonance. We highlight 2015 KH162 as a likely member of this fossilized 3:1 population. Under any plausible migration scenario, nearly all high-perihelion objects in resonances beyond the 4:1 MMR (near 76 au) reach their orbits well after Neptune stops migrating and compose a recently generated, dynamically active population.

NoSQL Application Redesign may be Unnecessary for Most Corporation Cloud Migration Deployments

A great deal of cloud research implies that application redesign is a necessity in order to take full advantage of migration to the cloud, and developers are urged to consider migrating legacy application onto various NoSQL architectures. It may be argued however, that many enterprises have non-web-centric business models and relatively few of their applications may need the database scaling capability that cloud deployment with NoSQL affords. The authors contend that these corporations, in the process of cloud migration, are less motivated by the promise of NoSQL than by gaining greater operational efficiencies and cost-effectiveness. Several Cloud Infrastructure-as-a-Service (IaaS) migration scenarios for five top cloud vendors were studied using cost versus effectiveness ratios (CE). The results show that the greatest cost-benefit was gained by simply moving off physical resources and onto the cloud. This was coined the 'simple yet effective' model, as opposed to continuing along the technology curve to fully implement NoSQL solutions, coined the 'complex and robust' model.

Abstract 5058: Hitting the brakes on the migratory capacity of tumoral cells: Targeting key regulators of actin dynamics in prostate cancer

Abstract Prostate Cancer (PCa) is the second leading cause of cancer in men. PCa cells display abnormal expression of cytoskeletal proteins resulting in an augmented capacity to resist chemotherapy and colonize other organs. We have previously shown that heme-oxygenase 1 (HO-1) has a strong anti-tumoral effect in prostate cancer (PCa) and regulates the adhesive properties of PCa cells. Innovative high-throughput proteomic platforms are now identifying and quantifying new specific and sensitive biomarkers for PCa detection, stratification and treatment. Towards this end, we undertook an in-depth mass spectrometry-based proteomics study to build the Heme-oxygenase 1 (HO-1) interactome in PCa, in an effort to identify HO-1 molecular partners associated to the integrity of the cellular architecture and assess actin dynamics of PCa cells under HO-1 modulation. The proteomics analysis of HO-1 interacting proteins yielded several cytoskeletal-associated proteins regulating actin filament dynamics, such as gelsolin, lasp1, SIPA1L1, testin, moesin, tropomodulin and vinculin. The bioinformatics screening across the Oncomine platform revealed that the RNA expression profiles of the cytoskeletal HO-1 interacting proteins, lie within the 10 percent of the most consistently low-expressed genes in prostate adenocarcinoma compared to normal tissue. Motility changes were assessed on fiber-like 2D migration scenarios displaying a reduced frequency in migration events and in migration speed under hemin exposure, a specific pharmacological inducer of HO-1. A significant higher proportion of filopodia-like protrusions among neighboring cells and cellular contacts were observed when HO-1 was induced; effects reversed under HO-1 silencing. Altogether, our experimental findings demonstrate that HO-1 modulation in PCa induces the remodeling of the actin filament architecture at filopodia, alters the migratory patterns and cellular morphology, showcasing the relevance of the cytoskeletal proteins as potential therapeutic targets against the aggressive and metastatic disease. Citation Format: Alejandra V. Paez, Carla Pallavicini, Federico Schuster, Jimena Giudice, Pia Valacco, Estefania Labanca, Nicolas Anselmino, Emiliano Ortiz, Maria Binaghi, Javier Cotignola, Marcelo Marti, Luciana Bruno, Valeria Levi, Nora Navone, Elba Vazquez, Geraldine Gueron. Hitting the brakes on the migratory capacity of tumoral cells: Targeting key regulators of actin dynamics in prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5058.

New insights on the formation of nuclear star clusters

Nuclear Clusters (NCs) are common stellar systems in the centres of galaxies. Yet, the physical mechanisms involved in their formation are still debated. Using a parsec-resolution hydrodynamical simulation of a dwarf galaxy, we propose an updated formation scenario for NCs. In this 'wet migration scenario', a massive star cluster forms in the gas-rich disc, keeping a gas reservoir, and growing further while it migrates to the centre via a combination of interactions with other substructures and dynamical friction. A wet merger with another dense cluster and its own gas reservoir can occur, although this is not a pre-requisite for the actual formation of the NC. The merging process does significantly alter the properties of the NC (mass, morphology, star formation history), also quenching the on-going local star formation activity, thus leading to interesting observational diagnostics for the physical origin of NCs. A population of lower mass clusters co-exist during the simulation, but these are either destroyed via tidal forces, or have high angular momentum preventing them to interact with the NC and contribute to its growth. The proposed updated scenario emphasises the role of gas reservoirs associated with the densest star clusters formed in a gas-rich low-mass galaxy.

THE OCCURRENCE OF ADDITIONAL GIANT PLANETS INSIDE THE WATER–ICE LINE IN SYSTEMS WITH HOT JUPITERS: EVIDENCE AGAINST HIGH-ECCENTRICITY MIGRATION

ABSTRACT The origin of Jupiter-mass planets with orbital periods of only a few days is still uncertain. It is widely believed that these planets formed near the water–ice line of the protoplanetary disk, and subsequently migrated into much smaller orbits. Most of the proposed migration mechanisms can be classified either as disk-driven migration, or as excitation of a very high eccentricity followed by tidal circularization. In the latter scenario, the giant planet that is destined to become a hot Jupiter spends billions of years on a highly eccentric orbit, with apastron near the water–ice line. Eventually, tidal dissipation at periastron shrinks and circularizes the orbit. If this is correct, then it should be especially rare for hot Jupiters to be accompanied by another giant planet interior to the water–ice line. Using the current sample of giant planets discovered with the Doppler technique, we find that hot Jupiters with P orb < 10 days are no more or less likely to have exterior Jupiter-mass companions than longer-period giant planets with P orb ≥ 10 days. This result holds for exterior companions both inside and outside of the approximate location of the water–ice line. These results are difficult to reconcile with the high-eccentricity migration scenario for hot Jupiter formation.

The formation efficiency of close-in planets via Lidov–Kozai migration: analytic calculations

Lidov-Kozai oscillations of planets in stellar binaries, combined with tidal dissipation, can lead to the formation of hot Jupiters (HJs) or tidal disruption of planets. Recent population synthesis studies have found that the fraction of systems resulting in HJs (F_HJ) depends strongly on the planet mass, host stellar type and tidal dissipation strength, while the total migration fraction F_mig = F_ HJ + F_dis (including both HJ formation and tidal disruption) exhibits much weaker dependence. We present an analytical method for calculating F_HJ and F_mig in the Lidov-Kozai migration scenario. The key ingredient of our method is to determine the critical initial planet-binary inclination angle that drives the planet to reach sufficiently large eccentricity for efficient tidal dissipation or disruption. This calculation includes the effects of the octupole potential and short-range forces on the planet. Our analytical method reproduces the resulting planet migration/disruption fractions from population synthesis, and can be easily implemented for various planet, stellar/companion types, and for different distributions of initial planetary semi-major axes, binary separations and eccentricities. We extend our calculations to planets in the super-Earth mass range and discuss the conditions for such planets to survive Lidov-Kozai migration and form close-in rocky planets.