WorldWideScience

Sample records for rapidly migrating hmg2

  1. Are Melt Migration Rates Through the Mantle Universally Rapid?

    Science.gov (United States)

    Reagan, M. K.; Sims, K. W.

    2001-12-01

    Significant enrichments in 226Ra over 230Th have been observed in basalts erupted in nearly all tectonic settings. These enrichments generally are greatest in lavas with low concentrations of U, Th and other incompatible elements, including those from mid-ocean ridges and "depleted" volcanic arcs. Excesses of 226Ra over 230Th in mid-ocean ridge settings are commonly attributed to smaller bulk partition coefficients for Ra with respect to Th during mantle melting, and extraction of ingrown Ra into melts slowly migrating through interconnected pore space. In contrast, 226Ra excesses in basalts from volcanic arcs have been attributed to fluid additions from subducting slabs to the sources of the basalt and rapid (102 - 103y) melt migration to the surface (e.g. Turner et al., 2001). Such rapid melt velocities imply channeled flow rather than diffuse porous flow, and suggest that basalts from other tectonic settings migrate similarly rapidly. Here, we show that the compositions of basalts from both arc and mid-ocean ridge settings indeed can be explained by melting models involving rapid transit times to the surface. Simple fluxed melting models and rapid transfer of melt to the surface explain the U-Th-Ra systematics and incompatible trace element compositions of arc basalts. The U-Th-Ra and trace element data for young MORB from the East Pacific Rise (Sims et al. 2001) and the Siqueiros transform (Lundstrom et al. 1999) are modeled using simple 2-d polybaric melting based on Braun et al. (2000) and rapid melt migration rates. Successful models mix small-degree fractional melts derived from a broad cross-sectional area of mantle at depth with high-degree melts derived from a small cross-sectional area of shallow mantle that is the aged residue of the small degree melt.

  2. Contextual background to the rapid increase in migration from ...

    African Journals Online (AJOL)

    ... documented and undocumented migrants dispersed in countries in the region, predominantly South Africa and Botswana, and far-flung countries like the United Kingdom, the United States of America, Canada, Australia and New Zealand. Whereas in the past male migration was dominant, by 2000 women have migrated ...

  3. Random migration and signal integration promote rapid and robust T cell recruitment.

    Science.gov (United States)

    Textor, Johannes; Henrickson, Sarah E; Mandl, Judith N; von Andrian, Ulrich H; Westermann, Jürgen; de Boer, Rob J; Beltman, Joost B

    2014-08-01

    To fight infections, rare T cells must quickly home to appropriate lymph nodes (LNs), and reliably localize the antigen (Ag) within them. The first challenge calls for rapid trafficking between LNs, whereas the second may require extensive search within each LN. Here we combine simulations and experimental data to investigate which features of random T cell migration within and between LNs allow meeting these two conflicting demands. Our model indicates that integrating signals from multiple random encounters with Ag-presenting cells permits reliable detection of even low-dose Ag, and predicts a kinetic feature of cognate T cell arrest in LNs that we confirm using intravital two-photon data. Furthermore, we obtain the most reliable retention if T cells transit through LNs stochastically, which may explain the long and widely distributed LN dwell times observed in vivo. Finally, we demonstrate that random migration, both between and within LNs, allows recruiting the majority of cognate precursors within a few days for various realistic infection scenarios. Thus, the combination of two-scale stochastic migration and signal integration is an efficient and robust strategy for T cell immune surveillance.

  4. Rapid Reactivation of Cyanobacterial Photosynthesis and Migration upon Rehydration of Desiccated Marine Microbial Mats

    KAUST Repository

    Chennu, Arjun

    2015-12-24

    Desiccated cyanobacterial mats are the dominant biological feature in the Earth’s arid zones. While the response of desiccated cyanobacteria to rehydration is well-documented for terrestrial systems, information about the response in marine systems is lacking. We used high temporal resolution hyperspectral imaging, liquid chromatography, pulse-amplitude fluorometry, oxygen microsensors, and confocal laser microscopy to study this response in a desiccated microbial mat from Exmouth Gulf, Australia. During the initial 15 min after rehydration chlorophyll a concentrations increased 2–5 fold and cyanobacterial photosynthesis was re-established. Although the mechanism behind this rapid increase of chlorophyll a remains unknown, we hypothesize that it involves resynthesis from a precursor stored in desiccated cyanobacteria. The subsequent phase (15 min–48 h) involved migration of the reactivated cyanobacteria toward the mat surface, which led, together with a gradual increase in chlorophyll a, to a further increase in photosynthesis. We conclude that the response involving an increase in chlorophyll a and recovery of photosynthetic activity within minutes after rehydration is common for cyanobacteria from desiccated mats of both terrestrial and marine origin. However, the response of upward migration and its triggering factor appear to be mat-specific and likely linked to other factors.

  5. Rapid expansion and pseudo spectral implementation for reverse time migration in VTI media

    KAUST Repository

    Pestana, Reynam C

    2012-04-24

    In isotropic media, we use the scalar acoustic wave equation to perform reverse time migration (RTM) of the recorded pressure wavefield data. In anisotropic media, P- and SV-waves are coupled, and the elastic wave equation should be used for RTM. For computational efficiency, a pseudo-acoustic wave equation is often used. This may be solved using a coupled system of second-order partial differential equations. We solve these using a pseudo spectral method and the rapid expansion method (REM) for the explicit time marching. This method generates a degenerate SV-wave in addition to the P-wave arrivals of interest. To avoid this problem, the elastic wave equation for vertical transversely isotropic (VTI) media can be split into separate wave equations for P- and SV-waves. These separate wave equations are stable, and they can be effectively used to model and migrate seismic data in VTI media where |ε- δ| is small. The artifact for the SV-wave has also been removed. The independent pseudo-differential wave equations can be solved one for each mode using the pseudo spectral method for the spatial derivatives and the REM for the explicit time advance of the wavefield. We show numerically stable and high-resolution modeling and RTM results for the pure P-wave mode in VTI media. © 2012 Sinopec Geophysical Research Institute.

  6. Rapid expansion method (REM) for time‐stepping in reverse time migration (RTM)

    KAUST Repository

    Pestana, Reynam C.

    2009-01-01

    We show that the wave equation solution using a conventional finite‐difference scheme, derived commonly by the Taylor series approach, can be derived directly from the rapid expansion method (REM). After some mathematical manipulation we consider an analytical approximation for the Bessel function where we assume that the time step is sufficiently small. From this derivation we find that if we consider only the first two Chebyshev polynomials terms in the rapid expansion method we can obtain the second order time finite‐difference scheme that is frequently used in more conventional finite‐difference implementations. We then show that if we use more terms from the REM we can obtain a more accurate time integration of the wave field. Consequently, we have demonstrated that the REM is more accurate than the usual finite‐difference schemes and it provides a wave equation solution which allows us to march in large time steps without numerical dispersion and is numerically stable. We illustrate the method with post and pre stack migration results.

  7. Cell-scale dynamic recycling and cortical flow of the actin–myosin cytoskeleton for rapid cell migration

    Directory of Open Access Journals (Sweden)

    Shigehiko Yumura

    2012-11-01

    Actin and myosin II play major roles in cell migration. Whereas pseudopod extension by actin polymerization has been intensively researched, less attention has been paid to how the rest of the actin cytoskeleton such as the actin cortex contributes to cell migration. In this study, cortical actin and myosin II filaments were simultaneously observed in migrating Dictyostelium cells under total internal reflection fluorescence microscopy. The cortical actin and myosin II filaments remained stationary with respect to the substratum as the cells advanced. However, fluorescence recovery after photobleaching experiments and direct observation of filaments showed that they rapidly turned over. When the cells were detached from the substratum, the actin and myosin filaments displayed a vigorous retrograde flow. Thus, when the cells migrate on the substratum, the cortical cytoskeleton firmly holds the substratum to generate the motive force instead. The present studies also demonstrate how myosin II localizes to the rear region of the migrating cells. The observed dynamic turnover of actin and myosin II filaments contributes to the recycling of their subunits across the whole cell and enables rapid reorganization of the cytoskeleton.

  8. BREATHING FIRE: HOW STELLAR FEEDBACK DRIVES RADIAL MIGRATION, RAPID SIZE FLUCTUATIONS, AND POPULATION GRADIENTS IN LOW-MASS GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    El-Badry, Kareem; Geha, Marla [Department of Astronomy, Yale University, New Haven, CT (United States); Wetzel, Andrew; Hopkins, Philip F. [TAPIR, California Institute of Technology, Pasadena, CA USA (United States); Kereš, Dusan; Chan, T. K. [Department of Physics, Center for Astrophysics and Space Sciences, University of California at San Diego, La Jolla (United States); Faucher-Giguère, Claude-André, E-mail: kareem.el-badry@yale.edu [Department of Physics and Astronomy and CIERA, Northwestern University, Evanston, IL (United States)

    2016-04-01

    We examine the effects of stellar feedback and bursty star formation on low-mass galaxies (M{sub star} = 2 × 10{sup 6} − 5 × 10{sup 10} M{sub ⊙}) using the Feedback in Realistic Environments (FIRE) simulations. While previous studies emphasized the impact of feedback on dark matter profiles, we investigate the impact on the stellar component: kinematics, radial migration, size evolution, and population gradients. Feedback-driven outflows/inflows drive significant radial stellar migration over both short and long timescales via two processes: (1) outflowing/infalling gas can remain star-forming, producing young stars that migrate ∼1 kpc within their first 100 Myr, and (2) gas outflows/inflows drive strong fluctuations in the global potential, transferring energy to all stars. These processes produce several dramatic effects. First, galaxies’ effective radii can fluctuate by factors of >2 over ∼200 Myr, and these rapid size fluctuations can account for much of the observed scatter in the radius at fixed M{sub star}. Second, the cumulative effects of many outflow/infall episodes steadily heat stellar orbits, causing old stars to migrate outward most strongly. This age-dependent radial migration mixes—and even inverts—intrinsic age and metallicity gradients. Thus, the galactic-archaeology approach of calculating radial star formation histories from stellar populations at z = 0 can be severely biased. These effects are strongest at M{sub star} ≈ 10{sup 7–9.6} M{sub ⊙}, the same regime where feedback most efficiently cores galaxies. Thus, detailed measurements of stellar kinematics in low-mass galaxies can strongly constrain feedback models and test baryonic solutions to small-scale problems in ΛCDM.

  9. Influence of rapid rural-urban population migration on riverine nitrogen pollution: perspective from ammonia-nitrogen.

    Science.gov (United States)

    Zhang, Wangshou; Swaney, Dennis P; Hong, Bongghi; Howarth, Robert W; Li, Xuyong

    2017-09-30

    China is undergoing a rapid transition from a rural to an urban society. This societal change is a consequence of a national drive toward economic prosperity. However, accelerated urban development resulting from rapid population migration from rural to urban lands has led to high levels of untreated sewage entering aquatic ecosystems directly. Consequently, many of these regions have been identified as hot spots of riverine nitrogen (N) pollution because of the increasing level of urban point-source discharge. In order to address this concern, we assessed effects of urban development on ammonia-nitrogen (AN) loads using a panel data regression model. The model, expressed as an exponential function of anthropogenic N inputs multiplied by a power function of streamflow, was applied to 20 subwatersheds of the Huai River Basin for the years 2003-2010. The results indicated that this model can account for 81% of the variation in annual AN fluxes over space and time. Application of this model to three scenarios of urban development and sewage treatment (termed urbanization priority, sustainable development, and environmental priority) suggests that future N pollution will inevitably deteriorate if current urban environmental management and investment are not significantly improved. Stronger support for environmental management is very critical to alleviate N pollution and improve water quality. More effort should focus on improving sewage treatment and the N removal rate of the current sewage system in light of the increasing degree of urbanization.

  10. Optimization and pharmacological validation of a leukocyte migration assay in zebrafish larvae for the rapid in vivo bioactivity analysis of anti-inflammatory secondary metabolites.

    Directory of Open Access Journals (Sweden)

    María Lorena Cordero-Maldonado

    Full Text Available Over the past decade, zebrafish (Danio rerio have emerged as an attractive model for in vivo drug discovery. In this study, we explore the suitability of zebrafish larvae to rapidly evaluate the anti-inflammatory activity of natural products (NPs and medicinal plants used in traditional medicine for the treatment of inflammatory disorders. First, we optimized a zebrafish assay for leukocyte migration. Inflammation was induced in four days post-fertilization (dpf zebrafish larvae by tail transection and co-incubation with bacterial lipopolysaccharides (LPS, resulting in a robust recruitment of leukocytes to the zone of injury. Migrating zebrafish leukocytes were detected in situ by myeloperoxidase (MPO staining, and anti-inflammatory activity was semi-quantitatively scored using a standardized scale of relative leukocyte migration (RLM. Pharmacological validation of this optimized assay was performed with a panel of anti-inflammatory drugs, demonstrating a concentration-responsive inhibition of leukocyte migration for both steroidal and non-steroidal anti-inflammatory drugs (SAIDs and NSAIDs. Subsequently, we evaluated the bioactivity of structurally diverse NPs with well-documented anti-inflammatory properties. Finally, we further used this zebrafish-based assay to quantify the anti-inflammatory activity in the aqueous and methanolic extracts of several medicinal plants. Our results indicate the suitability of this LPS-enhanced leukocyte migration assay in zebrafish larvae as a front-line screening platform in NP discovery, including for the bioassay-guided isolation of anti-inflammatory secondary metabolites from complex NP extracts.

  11. Post-migration dietary changes among african refugees in Geneva: a rapid assessment study to inform nutritional interventions.

    Science.gov (United States)

    Kruseman, Maaike; Barandereka, Nelly-Ange; Hudelson, Patricia; Stalder, Hans

    2005-01-01

    To conduct an assessment of perceived dietary changes and problems by African asylum seekers, in order to develop appropriate nutritional education interventions. A cross-sectional qualitative study among a convenience sample. Analysis compared and contrasted reported dietary changes and migration-related difficulties. Nineteen interviews were analysed. After migration, main dietary changes were the decrease in different fruits and vegetables consumed weekly from 10 to 2 and 17 to 10 respectively. The number of respondents drinking sweetened beverages more than 3 times a week increased from 3 to 18. Reasons for changes were related to prices, taste, choice and accessibility. These dietary changes may have serious health consequences. Future remedial interventions based on suggestions of the respondents could easily be implemented.

  12. Toxoplasma gondii infection shifts dendritic cells into an amoeboid rapid migration mode encompassing podosome dissolution, secretion of TIMP-1, and reduced proteolysis of extracellular matrix.

    Science.gov (United States)

    Ólafsson, Einar B; Varas-Godoy, Manuel; Barragan, Antonio

    2018-03-01

    Dendritic cells (DCs) infected by Toxoplasma gondii rapidly acquire a hypermigratory phenotype that promotes systemic parasite dissemination by a "Trojan horse" mechanism in mice. Recent paradigms of leukocyte migration have identified the amoeboid migration mode of DCs as particularly suited for rapid locomotion in extracellular matrix and tissues. Here, we have developed a microscopy-based high-throughput approach to assess motility and matrix degradation by Toxoplasma-challenged murine and human DCs. DCs challenged with T. gondii exhibited dependency on metalloproteinase activity for hypermotility and transmigration but, strikingly, also dramatically reduced pericellular proteolysis. Toxoplasma-challenged DCs up-regulated expression and secretion of tissue inhibitor of metalloproteinases-1 (TIMP-1) and their supernatants impaired matrix degradation by naïve DCs and by-stander DCs dose dependently. Gene silencing of TIMP-1 by short hairpin RNA restored matrix degradation activity in Toxoplasma-infected DCs. Additionally, dissolution of podosome structures in parasitised DCs coincided with abrogated matrix degradation. Toxoplasma lysates inhibited pericellular proteolysis in a MyD88-dependent fashion whereas abrogated proteolysis persevered in Toxoplasma-infected MyD88-deficient DCs. This indicated that both TLR/MyD88-dependent and TLR/MyD88-independent signalling pathways mediated podosome dissolution and the abrogated matrix degradation. We report that increased TIMP-1 secretion and cytoskeletal rearrangements encompassing podosome dissolution are features of Toxoplasma-induced hypermigration of DCs with an impact on matrix degradation. Jointly, the data highlight how an obligate intracellular parasite orchestrates key regulatory cellular processes consistent with non-proteolytic amoeboid migration of the vehicle cells that facilitate its dissemination. © 2017 John Wiley & Sons Ltd.

  13. Antarctic killer whales make rapid, round-trip movements to subtropical waters: evidence for physiological maintenance migrations?

    Science.gov (United States)

    Durban, J W; Pitman, R L

    2012-04-23

    Killer whales (Orcinus orca) are important predators in high latitudes, where their ecological impact is mediated through their movements. We used satellite telemetry to provide the first evidence of migration for killer whales, characterized by fast (more than 12 km h(-1), 6.5 knots) and direct movements away from Antarctic waters by six of 12 type B killer whales tagged when foraging near the Antarctic Peninsula, including all tags transmitting for more than three weeks. Tags on five of these whales revealed consistent movements to subtropical waters (30-37° S) off Uruguay and Brazil, in surface water temperatures ranging from -1.9°C to 24.2°C; one 109 day track documented a non-stop round trip of almost 9400 km (5075 nmi) in just 42 days. Although whales travelled slower in the warmest waters, there was no obvious interruption in swim speed or direction to indicate calving or prolonged feeding. Furthermore, these movements were aseasonal, initiating over 80 days between February and April; one whale returned to within 40 km of the tagging site at the onset of the austral winter in June. We suggest that these movements may represent periodic maintenance migrations, with warmer waters allowing skin regeneration without the high cost of heat loss: a physiological constraint that may also affect other whales.

  14. Mortality in adult immigrants in the 2000s in Belgium: a test of the 'healthy-migrant' and the 'migration-as-rapid-health-transition' hypotheses.

    Science.gov (United States)

    Vandenheede, Hadewijch; Willaert, Didier; De Grande, Hannelore; Simoens, Steven; Vanroelen, Christophe

    2015-12-01

    Firstly, to map out and compare all-cause and cause-specific mortality patterns by migrant background in Belgium; and secondly, to probe into explanations for the observed patterns, more specifically into the healthy-migrant, acculturation and the migration-as-rapid-health-transition theories. Data comprise individually linked Belgian census-mortality follow-up data for the period 2001-2011. All official inhabitants aged 25-54 at time of the census were included. To delve into the different explanations, differences in all-cause and chronic- and infectious-disease mortality were estimated using Poisson regression models, adjusted for age, socioeconomic position and urbanicity. First-generation immigrants have lower all-cause and chronic-disease mortality than the host population. This mortality advantage wears off with length of stay and is more marked among non-Western than Western first-generation immigrants. For example, Western and non-Western male immigrants residing 10 years or more in Belgium have a mortality rate ratio for cardiovascular disease of 0.72 (95% CI 0.66-0.78) and 0.59 (95% CI 0.53-0.66), respectively (vs host population). The pattern of infectious-disease mortality in migrants is slightly different, with rather high mortality rates in first-generation sub-Saharan Africans and rather low rates in all other immigrant groups. As for second-generation immigrants, the picture is gloomier, with a mortality disadvantage that disappears after control for socioeconomic position. Findings are largely consistent with the healthy-migrant, acculturation and the migration-as-rapid-health-transition theories. The convergence of the mortality profile of second-generation immigrants towards that of the host population with similar socioeconomic position indicates the need for policies simultaneously addressing different areas of deprivation. © 2015 John Wiley & Sons Ltd.

  15. Evidence from a mouse model that epithelial cell migration and mesenchymal-epithelial transition contribute to rapid restoration of uterine tissue integrity during menstruation.

    Science.gov (United States)

    Cousins, Fiona L; Murray, Alison; Esnal, Arantza; Gibson, Douglas A; Critchley, Hilary O D; Saunders, Philippa T K

    2014-01-01

    In women dynamic changes in uterine tissue architecture occur during each menstrual cycle. Menses, characterised by the shedding of the upper functional layer of the endometrium, is the culmination of a cascade of irreversible changes in tissue function including stromal decidualisation, inflammation and production of degradative enzymes. The molecular mechanisms that contribute to the rapid restoration of tissue homeostasis at time of menses are poorly understood. A modified mouse model of menses was developed to focus on the events occurring within the uterine lining during endometrial shedding/repair. Decidualisation, vaginal bleeding, tissue architecture and cell proliferation were evaluated at 4, 8, 12, and 24 hours after progesterone (P4) withdrawal; mice received a single injection of bromodeoxyuridine (BrdU) 90 mins before culling. Expression of genes implicated in the regulation of mesenchymal to epithelial transition (MET) was determined using a RT2 PCR profiler array, qRTPCR and bioinformatic analysis. Mice exhibited vaginal bleeding between 4 and 12 hours after P4 withdrawal, concomitant with detachment of the decidualised cell mass from the basal portion of the endometrial lining. Immunostaining for BrdU and pan cytokeratin revealed evidence of epithelial cell proliferation and migration. Cells that appeared to be in transition from a mesenchymal to an epithelial cell identity were identified within the stromal compartment. Analysis of mRNAs encoding genes expressed exclusively in the epithelial or stromal compartments, or implicated in MET, revealed dynamic changes in expression, consistent with a role for reprogramming of mesenchymal cells so that they could contribute to re-epithelialisation. These studies have provided novel insights into the cellular processes that contribute to re-epithelialisation post-menses implicating both epithelial cell migration and mesenchymal cell differentiation in restoration of an intact epithelial cell layer. These

  16. Assessing native and introduced fish predation on migrating juvenile salmon in Priest Rapids and Wanapum Reservoirs, Columbia River, Washington, 2009--11

    Science.gov (United States)

    Counihan, Timothy D.; Hardiman, Jill M.; Burgess, Dave S.; Simmons, Katrina E.; Holmberg, Glen S.; Rogala, Josh A.; Polacek, Rochelle R.

    2012-01-01

    Hydroelectric development on the mainstem Columbia River has created a series of impoundments that promote the production of native and non-native piscivores. Reducing the effects of fish predation on migrating juvenile salmonids has been a major component of mitigating the effects of hydroelectric development in the Columbia River basin. Extensive research examining juvenile salmon predation has been conducted in the lower Columbia River. Fewer studies of predation have been done in the Columbia River upstream of its confluence with the Snake River; the most comprehensive predation study being from the early 1990s. The Public Utility District No. 2 of Grant County, Washington initiated a northern pikeminnow removal program in 1995 in an attempt to reduce predation on juvenile salmonids. However, there has been no assessment of the relative predation within the Priest Rapids Project since the removal program began. Further, there is concern about the effects of piscivores other than northern pikeminnow (Ptychocheilus oregonensis), such as channel catfish (Ictalurus punctatus), smallmouth bass (Micropterus dolomieu), and walleye (Sander vitreus, formerlyStizostedion vitreum). The Public Utility District No. 2 of Grant County, Washington and the Priest Rapids Coordinating Committee requested that the U.S. Geological Survey, in collaboration with the Washington Department of Fish and Wildlife, assist them in evaluating the effects of native and introduced predatory fish on migrating juvenile salmon. From 2009 to 2010, we conducted sampling in the 103 kilometers (64 river miles) of the Columbia River from the tailrace of Rock Island Dam downstream to the tailrace of Priest Rapids Dam. To assess predation, we used electrofishing to collect northern pikeminnow, smallmouth bass, and walleye to analyze their diets during 2009 and 2010. In 2009, we used methods to allow comparisons to a previous study conducted in 1993. During 2009, we also used an alternate sampling

  17. Estradiol attenuates EGF-induced rapid uPAR mobilization and cell migration via the G-protein-coupled receptor 30 in ovarian cancer cells

    DEFF Research Database (Denmark)

    Henic, Emir; Noskova, Vera; Høyer-Hansen, Gunilla

    2009-01-01

    and cell migration in ovarian cancer cells and further to identify the ER involved.We used 7 ovarian cancer cell lines, cell migration assay, cellular binding of (125)I-uPA, cellular degradation of (125)I-uPA/PAI-1 complex, enzyme-linked immunosorbent assay for uPAR, solid-phase enzyme immunoassay...

  18. Baseline corticosterone peaks in shorebirds with maximal energy stores for migration : A general preparatory mechanism for rapid behavioral and metabolic transitions?

    NARCIS (Netherlands)

    Piersma, T; Reneerkens, J; Ramenofsky, M

    2000-01-01

    In captive red knots (Calidris canutus, Scolopacidae) showing a regulated body mass increase of 50% related to their migration from temperate staging sites to tundra:breeding grounds, plasma corticosterone concentrations increased from less than 10 ng.ml(-1) to levels as high-as 30 ng.ml(-1) when

  19. Rapid changes in the size of different functional organ and muscle groups during refueling in a long-distance migrating shorebird

    NARCIS (Netherlands)

    Piersma, T; Gudmundsson, GA; Lilliendahl, K; Gudmundsson, Gudmundur A.

    1999-01-01

    The adaptive value of size changes in different organ and muscle groups was studied in red knots (Calidris canutus islandica) in relation to their migration. Birds were sampled on five occasions: at arrival in Iceland in May 1994, two times during subsequent refueling, at departure toward, and on

  20. 'Migration & Integration'

    OpenAIRE

    Lisa Pilgram

    2011-01-01

    Migration, Integration : [kommunalpolitische Herausforderungen]. - Augsburg : Geo-Anwenderzentrum, [ca. 2004]. - XVIII, 281 S. - (Angewandte Sozialgeographie ; 49) (GEO-Taschenbuch). - Zugl.: Augsburg, Univ., Diss., 2003

  1. Gendering Migration

    Directory of Open Access Journals (Sweden)

    Mirjana Morokvašić

    2014-12-01

    Full Text Available Migration patterns, migration discourse and underlying representations, migrants’ experiences, obligations and duties as well as the expectations relative to their migration are gendered. Since the pioneering feminist migration scholars’ questioning of men as a universal reference and the invisibility of women or their stereotypical representations as dependents in the mainstream production of knowledge on migration, the scholarship has evolved considerably. It is argued in the paper that the ongoing process of cross-fertilization of developments in two separate epistemologies, each initially questioning monolithic and essentialist visions of a “migrant” on one hand and a “woman” on the other, produced a fecund subfield of research “migration and gender”. The paper provides an insight into this, reviewing work on the issues related to gendering different phases of migration. Bridging migration and gender brought to the top of research agendas issues that used to be on the margins, creating new visibilities but leaving out other gendered dimensions of complex realities of migrant experience.

  2. Cohort migration.

    Science.gov (United States)

    Taeuber, K E

    1966-06-01

    Most migration analyses focus on net migration and are concerned with areal redistributions of population. Migration may also be studied as an event in the life-cycle of an individual, and migration rates may be defined as properties of cohorts. A number of efforts to examine migration as a cohort process has been hampered by the character of available data [or the United States. Rather than await the development of a registration system-either directly or via social security and tax records-the collection of residence histories is suggested as the most feasible approach to obtaining suitable data. A schematic representation of residence histories clarifies their relation to other types of migration data and illustrates the need to design such surveys with specific research purposes in mind. Exploratory work with the 1958 Residence History Supplement to the Current Population Survey (by Beale, Shryock, myself, and various colleagues) demonstrates the utility of this approach.Local studies have made fruitful use of residence histories but typically are unable to delineate birth cohorts or other appropriate base populations exposed to risk. Development of cohort migration techniques analogous to the life table approach to mortality or cohort Jertility analysis requires national data. But migration, unlike Jertility and mortality, involves events that are reversible and repeatable. Hence the demographer's stock of analytic tools requires expansion. To the sociologist-demographer, experimentation with cohort migration models seems to be getting at one of the crucial methodological problems of sociology, the analysis of social mobility. A mutually profitable interchange with students of social mobility is envisaged.

  3. CHO-S antibody titers >1 gram/liter using flow electroporation-mediated transient gene expression followed by rapid migration to high-yield stable cell lines.

    Science.gov (United States)

    Steger, Krista; Brady, James; Wang, Weili; Duskin, Meg; Donato, Karen; Peshwa, Madhusudan

    2015-04-01

    In recent years, researchers have turned to transient gene expression (TGE) as an alternative to CHO stable cell line generation for early-stage antibody development. Despite advances in transfection methods and culture optimization, the majority of CHO-based TGE systems produce insufficient antibody titers for extensive use within biotherapeutic development pipelines. Flow electroporation using the MaxCyte STX Scalable Transfection System is a highly efficient, scalable means of CHO-based TGE for gram-level production of antibodies without the need for specialized expression vectors or genetically engineered CHO cell lines. CHO cell flow electroporation is easily scaled from milligram to multigram quantities without protocol reoptimization while maintaining transfection performance and antibody productivity. In this article, data are presented that demonstrate the reproducibility, scalability, and antibody production capabilities of CHO-based TGE using the MaxCyte STX. Data show optimization of posttransfection parameters such as cell density, media composition, and feed strategy that result in secreted antibody titers >1 g/L and production of multiple grams of antibody within 2 weeks of a single CHO-S cell transfection. In addition, data are presented to demonstrate the application of scalable electroporation for the rapid generation of high-yield stable CHO cell lines to bridge the gap between early- and late-stage antibody development activities. © 2014 Society for Laboratory Automation and Screening.

  4. Rapid Migration of Radionuclides Leaked from High-Level Water Tanks; A Study of Salinity Gradients, Wetted Path Geometry and Water Vapor Transport

    Energy Technology Data Exchange (ETDEWEB)

    Anderson l. Ward; Glendon W. Gee; John S. Selker; Clay Cooper

    2002-04-24

    tens ion of imbibing solutions can enhance vertical fingered flow, this phenomenon was not observed in the field. Field tests showed that the fingered flow behavior was overwhelmed by the variability in texture resulting from differences in the depositional environment. Field plumes were characterized by lateral spreading with an average width to depth aspect ratio of 4. For both vertical fingers and lateral flow, the high ionic strength contributed to the vapor phase dilution of the waste, which increased waste volume and pushed the wetting from well beyond what would have occurred if the volume of material had remained unchanged from that initially released into the system. It was also observed that following significant vapor-phase dilution of this waste simulants that streams of colloids were ejected from the sediment surfaces. It was shown that due to the high-sodium content of the tank wastes the colloids were deflocculated below a critical salt concentration in Hanford sediments. Th e released colloids, which at the site would be expected to carry the bulk of the sorbed heavy metals and radioisotopes, were mobile though coarse Hanford sediments, but clogged finer layers. The developments resulting from this study are already being applied at Hanford in the nonisothermal prediction of the hypersaline, high pH waste migration in tank farms and in the development of inverse methods for history matching under DOE's Groundwater/Vadose Zone Integration Project at Hanford.

  5. Rapid Migration of Radionuclides Leaked from High-Level Water Tanks: A Study of Salinity Gradients, Wetted Path Geometry and Water Vapor Transport

    Energy Technology Data Exchange (ETDEWEB)

    Anderson L. Ward; Glendon W. Gee; John S. Selker; Caly Cooper

    2002-04-24

    tension of imbibing solutions can enhance vertical fingered flow, this phenomenon was not observed in the field. Field tests of showed that the fingered flow behavior was overwhelmed by the variability in texture resulting from differences in the depositional environment. Field plumes were characterized by lateral spreading with an average width to depth aspect ratio of 4. For both vertical fingers and lateral flow, the high ionic strength contributed to the vapor phase dilution of the waste, which increased waste volume and pushed the wetting from well beyond what would have occurred if the volume of material had remained unchanged from that initially released into the system. It was also observed that following significant vapor-phase dilution of the waste simulants that streams of colloids were ejected from the sediment surfaces. It was shown that due to the high-sodium content of the tank wastes the colloids were deflocculated below a critical salt concentration in Hanford sediment s. The released colloids, which at the site would be expected to carry the bulk of the sorbed heavy metals and radioisotopes, were mobile though coarse Hanford sediments, but clogged finer layers. The developments resulting from this study are already being applied at Hanford in the nonisothermal prediction of the hypersaline, high pH waste migration in tank farms and in the development of inverse methods for history matching under DOE's Groundwater/Vadose Zone Integration Project at Hanford.

  6. [Internal migration].

    Science.gov (United States)

    Borisovna, L

    1991-06-01

    Very few studies have been conducted that truly permit explanation of internal migration and it repercussions on social and economic structure. It is clear however that a profound knowledge of the determinants and consequences of internal migration will be required as a basis for economic policy decisions that advance the goal of improving the level of living of the population. the basic supposition of most studies of the relationship of population and development is that socioeconomic development conditions demographic dynamics. The process of development in Mexico, which can be characterized by great heterogeneity, consequently produces great regional disparities. At the national level various studies have estimated the volume of internal migration in Mexico, but they have usually been limited to interstate migration because the main source of data, the census, is classified by states. But given the great heterogeneity within states in all the elements related to internal migration, it is clear that studies of internal migration within states are also needed. Such studies are almost nonexistent because of their technical difficulty. National level studies show that interstate migration increased significantly between 1940-80. The proportion of Mexicans living outside their states of birth increased by 558% in those years, compared to the 342% increase in the total Mexican population. Although Puebla has a high rate of increase, migration has kept it below Mexico's national growth rate. Migration between Puebla and other states and within Puebla has led to an increasing unevenness of spatial distribution. Between 1970-80, 57 of Puebla's municipios had growth rates above the state average of 2.8%/year, 6 had growth rates equal to the average, and 129 had growth rates that were below the average but not negative. 25 states with negative growth rates that were considered strongly expulsive. In 1980, 51.7% of the population was concentrated in the 57 municipios

  7. Migrating Worker

    DEFF Research Database (Denmark)

    Hansen, Hans

    This is the preliminary report on the results obtained in the Migrating Worker-project. This project was initiated by the Danish Ministry of Finance with the aim of illustrating the effects of the 1408/71 agreement and the bilateral double taxation agreements Denmark has with the countries included...

  8. Dateline Migration.

    Science.gov (United States)

    Tomasi, Lydio E., Ed.

    1995-01-01

    Presents data on international migration and its effects in and between various countries in North America, Europe, and Africa. Discussions include refugee, immigrant, and migrant worker flows; the legal, political, and social problems surrounding immigrants; alien terrorism and law enforcement problems; and migrant effects on education, social…

  9. A preference for migration

    OpenAIRE

    Stark, Oded

    2007-01-01

    At least to some extent migration behavior is the outcome of a preference for migration. The pattern of migration as an outcome of a preference for migration depends on two key factors: imitation technology and migration feasibility. We show that these factors jointly determine the outcome of a preference for migration and we provide examples that illustrate how the prevalence and transmission of a migration-forming preference yield distinct migration patterns. In particular, the imitation of...

  10. Migration, Rural Poverty and Community Natural Resource ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Migration, Rural Poverty and Community Natural Resource Management in Cambodia. Cambodia has a long history of migration, dislocation and forced resettlement. Years of strife and turmoil, rapid population growth, and agricultural development have led to a situation where most irrigated and flood-fed land is under ...

  11. Globalization, Migration and Development

    Directory of Open Access Journals (Sweden)

    George, Susan

    2002-01-01

    Full Text Available EnglishMigration may become the most important branch of demography in the earlydecades of the new millennium in a rapidly globalizing world. This paper discusses the causes, costsand benefits of international migration to countries of the South and North, and key issues of commonconcern. International migration is as old as national boundaries, though its nature, volume,direction, causes and consequences have changed. The causes of migration are rooted in the rate ofpopulation growth and the proportion of youth in the population, their education and training,employment opportunities, income differentials in society, communication and transportationfacilities, political freedom and human rights and level of urbanization. Migration benefits the Souththrough remittances of migrants, improves the economic welfare of the population (particularly womenof South countries generally, increases investment, and leads to structural changes in the economy.However, emigration from the South has costs too, be they social or caused by factors such as braindrain. The North also benefits by migration through enhancement of economic growth, development ofnatural resources, improved employment prospects, social development and through exposure toimmigrants' new cultures and lifestyles. Migration also has costs to the North such as of immigrantintegration, a certain amount of destabilization of the economy, illegal immigration, and socialproblems of discrimination and exploitation. Issues common to both North and South include impact onprivate investment, trade, international cooperation, and sustainable development. Both North andSouth face a dilemma in seeking an appropriate balance between importing South's labour or itsproducts and exporting capital and technology from the North.FrenchLa migration est sans doute devenue la partie la plus importante de la démographie des premières décennies du nouveau millénaire dans un monde qui change rapidement. Ce

  12. Dispersal and migration

    Directory of Open Access Journals (Sweden)

    Schwarz, C.

    2004-06-01

    Full Text Available Ringing of birds unveiled many aspects of avian migration and dispersal movements. However, there is even much more to be explored by the use of ringing and other marks. Dispersal is crucial in understanding the initial phase of migration in migrating birds as it is to understand patterns and processes of distribution and gene flow. So far, the analysis of migration was largely based on analysing spatial and temporal patters of recoveries of ringed birds. However, there are considerable biases and pitfalls in using recoveries due to spatial and temporal variation in reporting probabilities. Novel methods are required for future studies separating the confounding effects of spatial and temporal heterogeneity of recovery data and heterogeneity of the landscape as well. These novel approaches should aim a more intensive and novel use of the existing recovery data by taking advantage of, for instance, dynamic and multistate modeling, should elaborate schemes for future studies, and should also include other marks that allow a more rapid data collection, like telemetry, geolocation and global positioning systems, and chemical and molecular markers. The latter appear to be very useful in the delineating origin of birds and connectivity between breeding and non–breeding grounds. Many studies of migration are purely descriptive. However, King and Brooks (King & Brooks, 2004 examine if movement patterns of dolphins change after the introduction of a gillnet ban. Bayesian methods are an interesting approach to this problem as they provide a meaningful measure of the probability that such a change occurred rather than simple yes/no response that is often the result of classical statistical methods. However, the key difficulty of a general implementation of Bayesian methods is the complexity of the modelling —there is no general userfriendly package that is easily accessible to most scientists. Drake and Alisauskas (Drake & Alisauskas, 2004 examine the

  13. [Rural migration in Poland].

    Science.gov (United States)

    Rakowski, W

    1985-01-01

    Migration of the rural population in Poland from 1946 to 1983 is analyzed, with a focus on rural-urban migration. Consideration is given to regional variations in migration patterns, the causes of migration, and the impact of migration on areas of origin.

  14. Globalisation and international migration in Asia.

    Science.gov (United States)

    Hugo, G

    1998-03-01

    "The present paper attempts to summarise the major contemporary trends in international migration in Asia and how this is related to the rapid demographic transition occurring across most of the region. The diversity of types of mobility is one of the striking features of Asian international migration and developments in each major type [are] discussed in the paper. It is then argued that there are elements within the Asian migration system that give it a momentum which to some extent operates outside of the influence of economic and political trends. Finally some emerging issues in Asian international migration are briefly addressed. These include the scale and effects of remittances, the feminisation of migration, undocumented migration, increasing government involvement and brain drain issues." (EXCERPT)

  15. Migration of birds

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report covers the migration of birds. Topics covered include why birds migrate, when birds migrate, speed, altitude, courses, distance, major flyways and...

  16. Microwave heating causes rapid degradation of antioxidants in polypropylene packaging, leading to greatly increased specific migration to food simulants as shown by ESI-MS and GC-MS.

    Science.gov (United States)

    Alin, Jonas; Hakkarainen, Minna

    2011-05-25

    Microwave heating of commercial microwavable polypropylene packaging in contact with fatty food simulants caused significant antioxidant degradation and increased specific migration as shown by electrospray ionization-mass spectrometry (ESI-MS) and gas chromatography-mass spectrometry (GC-MS). Degradation of the antioxidants Irgafos 168 and Irganox 1010 was not detected during conventional heating of polypropylene packaging at the same temperature. The migration into aqueous food simulants was primarily restricted by the water solubility of the migrants. Using isooctane as fatty food simulant caused significant swelling and greatly enhanced overall migration values compared to the other fatty food simulant, 99.9% ethanol, or the aqueous food simulants 10% ethanol, 3% acetic acid, or water. ESI-MS spectra clearly reflected the overall migration values, and the number and amount of compounds detected decreased as the hydrophilicity of the food simulant increased. ESI-MS was shown to be an excellent tool for the analysis of semivolatile migrants and a good complement to GC-MS analysis of volatile migrants.

  17. Population-level scaling of avian migration speed with body size and migration distance for powered fliers.

    Science.gov (United States)

    La Sorte, Frank A; Fink, Daniel; Hochachka, Wesley M; DeLong, John P; Kelling, Steve

    2013-08-01

    Optimal migration theory suggests specific scaling relationships between body size and migration speed for individual birds based on the minimization of time, energy, and risk. Here we test if the quantitative predictions originating from this theory can be detected when migration decisions are integrated across individuals. We estimated population-level migration trajectories and daily migration speeds for the combined period 2007-2011 using the eBird data set. We considered 102 North American bird species that use flapping or powered flight during migration. Many species, especially in eastern North America, had looped migration trajectories that traced a clockwise path with an eastward shift during autumn migration. Population-level migration speeds decelerated rapidly going into the breeding season, and accelerated more slowly during the transition to autumn migration. In accordance with time minimization predictions, spring migration speeds were faster than autumn migration speeds. In agreement with optimality predictions, migration speeds of powered flyers scaled negatively with body mass similarly during spring and autumn migration. Powered fliers with longer migration journeys also had faster migration speeds, a relationship that was more pronounced during spring migration. Our findings indicate that powered fliers employed a migration strategy that, when examined at the population level, was in compliance with optimality predictions. These results suggest that the integration of migration decisions across individuals does result in population-level patterns that agree with theoretical expectations developed at the individual level, indicating a role for optimal migration theory in describing the mechanisms underlying broadscale patterns of avian migration for species that use powered flight.

  18. ESCAP migration study gathers momentum.

    Science.gov (United States)

    1980-01-01

    A comparative study is being conducted in the ESCAP (Economic and Social Commission for Asia and the Pacific) region on the relationships of migration and urbanization to development. The 1st stage of the study will entail the preparation of country reports on the census analysis of migration, urbanization and development. The 2nd stage will involve preparation of a series of national migration surveys. The 3rd phase will involve assisting member governments to formulate a comprehensive population redistribution policy as part of their national development planning. 1st-phase country reports have been completed in Sri Lanka, South Korea, the Philippines, and Indonesia. Migration in Sri Lanka has largely been rural-to-rural with little urbanization so far. The picture in South Korea has been the opposite, with rapid urbanization in the 1960s and 1970s; the government is hoping to divert some population to smaller cities away from Seoul. The pattern in the Philippines is 1 of urban primacy with the metropolis of Manila accounting for over 1/3 of the country's total population. Indonesia is characterized by a dense heartland in the Java-Bali regions. However, the rate of urbanization here has been slower. Migrants in all the countries studied are preponderantly young. The sex differential varies from country to country. The influence of migration on subsequent fertility is unknown.

  19. Morphological constraints on changing avian migration phenology.

    Science.gov (United States)

    Møller, A P; Rubolini, D; Saino, N

    2017-06-01

    Many organisms at northern latitudes have responded to climate warming by advancing their spring phenology. Birds are known to show earlier timing of spring migration and reproduction in response to warmer springs. However, species show heterogeneous phenological responses to climate warming, with those that have not advanced or have delayed migration phenology experiencing population declines. Although some traits (such as migration distance) partly explain heterogeneity in phenological responses, the factors affecting interspecies differences in the responsiveness to climate warming have yet to be fully explored. In this comparative study, we investigate whether variation in wing aspect ratio (reflecting relative wing narrowness), an ecomorphological trait that is strongly associated with flight efficiency and migratory behaviour, affects the ability to advance timing of spring migration during 1960-2006 in a set of 80 European migratory bird species. Species with larger aspect ratio (longer and narrower wings) showed smaller advancement of timing of spring migration compared to species with smaller aspect ratio (shorter and wider wings) while controlling for phylogeny, migration distance and other life-history traits. In turn, migration distance positively predicted aspect ratio across species. Hence, species that are better adapted to migration appear to be more constrained in responding phenologically to rapid climate warming by advancing timing of spring migration. Our findings corroborate the idea that aspect ratio is a major evolutionary correlate of migration, and suggest that selection for energetically efficient flights, as reflected by high aspect ratio, may hinder phenotypically plastic/microevolutionary adjustments of migration phenology to ongoing climatic changes. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  20. Application of platelet-rich plasma accelerates the wound healing process in acute and chronic ulcers through rapid migration and upregulation of cyclin A and CDK4 in HaCaT cells.

    Science.gov (United States)

    Kim, Sung-Ae; Ryu, Han-Won; Lee, Kyu-Suk; Cho, Jae-We

    2013-02-01

    Application of autologous platelet-rich plasma (PRP) has been used for chronic wound healing. The aim of this study was to evaluate the effect of PRP on the wound healing processes of both acute and chronic ulcers and the underlying molecular mechanisms involved. We treated 16 patients affected by various acute and chronic ulcers with PRP. We performed molecular studies of cell proliferation, migration assays, immunoblotting and chloramphenicol acetyltransferase (CAT) assays in PRP-treated HaCaT keratinocyte cells. PRP treatment induced increased rates of cell proliferation and cell migration of HaCaT cells. In addition, the expression of cyclin A and cyclin dependent kinase (CDK) 4 proteins was markedly increased with a low concentration (0.5%) of PRP treatment in HaCaT cells. In 11 patients with chronic ulcers, including stasis ulcers, diabetic ulcers, venous leg ulcers, livedoid vasculitis, claw foot and traumatic ulcers, 9 patients showed 90-100% epithelization after 15.18 days. In 5 patients with acute ulcers, such as dehiscence, open wound and burn wound, 80-100% epithelization was achieved between 4 to 20 days. Topical application of PRP to acute and chronic skin ulcers significantly accelerated the epithelization process, likely through upregulation of the cell cycle regulatory proteins cyclin A and CDK4.

  1. Malaysia and forced migration

    National Research Council Canada - National Science Library

    Arzura Idris

    2012-01-01

    This paper analyzes the phenomenon of "forced migration" in Malaysia. It examines the nature of forced migration, the challenges faced by Malaysia, the policy responses and their impact on the country and upon the forced migrants...

  2. Migration and revolution

    Directory of Open Access Journals (Sweden)

    Nando Sigona

    2012-06-01

    Full Text Available The Arab Spring has not radically transformed migration patterns in the Mediterranean, and the label ‘migration crisis’ does not do justice to the composite and stratified reality.

  3. Essays on temporary migration

    OpenAIRE

    Mestres Domenech, J.

    2012-01-01

    My thesis dissertation focuses on the temporariness of migration, its diverse effects as well as on migration selection. The first paper, A Dynamic Model of Return Migration analyzes the decision process underlying return migration using a dynamic model. We explain how migrants decide whether to stay or to go back to their home country together with their savings and consumption decisions. We simulate our model with return intentions and perform policy simulations. The se...

  4. Irregular Migration of Egyptians

    OpenAIRE

    ROMAN, Howaida

    2008-01-01

    Euro-Mediterranean Consortium for Applied Research on International Migration (CARIM) After defining irregular migration and tackling its different dimensions, the analytical note proposes to analyse the causes and dynamics of irregular migration in Egypt. It highlights furthermore the determinants of EU Policies in the realm of irregular migration, and Egypt’s policy-making approach towards irregular migrants. The conclusion emphasizes the necessity of forging coherent and effective polic...

  5. More Myths of Migration.

    Science.gov (United States)

    Basch, Linda; Lerner, Gail

    1986-01-01

    Challenges "myths" about women and migration, including (1) the causes of migration are economic, not racism; (2) migrant women receive support from feminist groups and trade unions; (3) transnational corporations are positive forces in developing nations; (4) migration today has little impact on family life; and (5) most migrants cluster in…

  6. Assessing Migration Risk for Scientific Data Formats

    Directory of Open Access Journals (Sweden)

    Chris Frisz

    2012-03-01

    Full Text Available The majority of information about science, culture, society, economy and the environment is born digital, yet the underlying technology is subject to rapid obsolescence. One solution to this obsolescence, format migration, is widely practiced and supported by many software packages, yet migration has well known risks. For example, newer formats – even where similar in function – do not generally support all of the features of their predecessors, and, where similar features exist, there may be significant differences of interpretation.There appears to be a conflict between the wide use of migration and its known risks. In this paper we explore a simple hypothesis – that, where migration paths exist, the majority of data files can be safely migrated leaving only a few that must be handled more carefully – in the context of several scientific data formats that are or were widely used. Our approach is to gather information about potential migration mismatches and, using custom tools, evaluate a large collection of data files for the incidence of these risks. Our results support our initial hypothesis, though with some caveats. Further, we found that writing a tool to identify “risky” format features is considerably easier than writing a migration tool.

  7. Clandestine labor migration to Taiwan.

    Science.gov (United States)

    Tsay, C

    1992-01-01

    "Illegal migration to Taiwan is a recent phenomenon but with a rapid rate of increase. Most illegal foreign workers enter on visitor's visas and overstay. This paper's detailed analysis of official data reveals that Malaysia, Philippines, Indonesia and Thailand are the major sources, providing a stock of mostly male workers numbering around 40,000. Sociodemographic and attitudinal changes among Taiwanese workers coupled with labor shortages in low-skilled jobs are pressuring the Taiwanese government to formulate plans for a systematic importation of foreign labor." excerpt

  8. Gender and Migration : a Women's Movement Perspective on ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Gender and Migration : a Women's Movement Perspective on Negotiating Rights (India). Women's movements in India are struggling to address problems arising from rapidly changing social relations and vulnerabilities associated with, among other things, the phenomenon of migration. This project will allow a ...

  9. Migration to and from the terai: shifting movements and motives

    NARCIS (Netherlands)

    Gartaula, H.N.; Niehof, Anke

    2013-01-01

    In Nepal, the historical evidence shows that migration to the terai increased after the eradication of malaria in the late 1950s and has been increasing ever since. More recently, however, out-migration from the terai is rapidly increasing. By applying both qualitative and quantitative research

  10. Transnational Migration of Vietnamese Women in Asia | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Over the last decade, Asia has witnessed rapid growth in the feminization of migration. For example, during that period, more than 100 000 Vietnamese women migrated to other countries to work and a similar number to marry, through commercial arrangements. But, sending countries often lack the appropriate policies and ...

  11. ILLEGAL MIGRATION-CONCEPTUAL DELIMITATIONS

    Directory of Open Access Journals (Sweden)

    CRISTINA FLORINA POPESCU (PANAIT

    2013-05-01

    Full Text Available Illegal migration is a mobile phenomenon, which ignores national borders, a threat that originates outside the community and extends to Western societies. This phenomenon is becoming larger and irregular migrants are often in a precarious situation and exposed to the criminals involved in various manifestations of organized crime. The future risk factors of the illegal migration are the demographic bomb, because the population is decreasing in European countries and increasing rapidly in poorer countries, droughts, floods, deforestation, that cause conflicts between climate refugees , extreme poverty, totalitarian regimes, epidemics, can trigger millions of people, the elderly and the working population imbalance which leads to the permanent import of immigrants To combat this phenomenon, states must engage and cooperate with each other. Measures taken by states must balance their integration policy for immigrants, legally residents and asylum policy to comply with international conventions. Also, states must adopt anti-immigrant policies, consisting of subordination visa policy to the interests of international security and exchange of information and, not least, to continue the Schengen process, as a value of humanitarian law applied in the field. The aim of the research is to characterize this dangerous phenomenon for the society and the goal is to identify strategies to combat illegal migration.

  12. Dialogues on migration policy

    OpenAIRE

    Giugni, Marco; Passy, Florence

    2006-01-01

    Dialogues on Migration Policy brings together leading American and European scholars of immigration politics to address migration policy. Editors Marco Giugni and Florence Passy's aim to present a number of informed "dialogues" addressing three main theoretical concerns in this field: the role of the national state in a globalizing world, the determinants of policy change, and the role of collective interests in migration policy. Adopting an unconventional format, the novelty of Dialogues on ...

  13. Many Faces of Migrations

    OpenAIRE

    Milica Antić Gaber; Marko Krevs

    2013-01-01

    Temporary or permanent, local or international, voluntary or forced, legal or illegal, registered or unregistered migrations of individuals, whole communities or individual groups are an important factor in constructing and modifying (modern) societies. The extent of international migrations is truly immense. At the time of the preparation of this publication more than 200 million people have been involved in migrations in a single year according to the United Nations. Furthermore, three time...

  14. Internal migration: why do Filipinos move?

    Science.gov (United States)

    Jolipa, N

    1980-01-01

    The rapid movement of Filipinos from 1 part of the Philippines to another is not a new phenomenon, but mobility has been increasing. A study conducted by Peter C. Smith revealed that interprovincial lifetime mobility of the national population increased from 15.8% in 1960 to 17.6% in 1970, while interregional mobility increased from 12.7% to 13.4%. People still disagree as to whether the size and rate of growth of the population are excessive, but there seems to be total consensus as regards its spatial imbalance. Because internal migration appears to be an important factor in national development, a need exists to examine different aspects of internal migration, such as the directions taken by migration flows, the migrants' reasons for moving, the migrants' characteristics, the migrants' success or lack of success at their places of destination, the social problems accompanying internal migration, effforts to deal with the problems caused by internal migration, and the implications of migration trends for policy and for the country's development programs. The most dominant migration trend in the Philippines in recent years has been toward the urban, or more accurately the suburban, areas adjacent to Metropolitan Manila. The city of Manila itself suffered a net outflow, further pointing to the trend toward suburbanization. Migration flows are primarily caused by economic reasons. About one half the sample of a Filipinas Foundation Study moved to provinces other than the province of birth in the pursuit of employment and other economic opportunities. A study of the country's migrant population age 15 and older showed that 53% of migrants were female. For male migrants, age ranges from 20-40; it ranges from 15-35 for females. Where cash income is concerned, migrants in Pernia's study of rural urban migration were better off than nonmigrants. Migrants were, on the average, as well off as native urbanites or metropolitanites. Among the more significant points raised by

  15. Regional Redistribution and Migration

    DEFF Research Database (Denmark)

    Manasse, Paolo; Schultz, Christian

    We study a model with free migration between a rich and a poor region. Since there is congestion, the rich region has an incentive to give the poor region a transfer in order to reduce immigration. Faced with free migration, the rich region voluntarily chooses a transfer, which turns out...... to be equal to that a social planner would choose. Provided migration occurs in equilibrium, this conclusion holds even in the presence of moderate mobility costs. However, large migration costs will lead to suboptimal transfers in the market solution...

  16. Migration and Its Consequences

    OpenAIRE

    Ivan Vasile Ivanoff

    2017-01-01

    ABSTRACT: Migration, as a social phenomenon, has an especially complex character and can be analyzed from the point of view of the state which is the source of the migration as well as from the point of view of the state which is the destination of the migration. Its causes are especially complex but the economic ones are determinant and are fundamentally different of the causes which determine the population to seek refuge in case of armed conflict. The effects of the migration are equally c...

  17. Migration into art

    DEFF Research Database (Denmark)

    Petersen, Anne Ring

    This book addresses a topic of increasing importance to artists, art historians and scholars of cultural studies, migration studies and international relations: migration as a profoundly transforming force that has remodelled artistic and art institutional practices across the world. It explores...... contemporary art's critical engagement with migration and globalisation as a key source for improving our understanding of how these processes transform identities, cultures, institutions and geopolitics. The author explores three interwoven issues of enduring interest: identity and belonging, institutional...... visibility and recognition of migrant artists, and the interrelations between aesthetics and politics, including the balancing of aesthetics, politics and ethics in representations of forced migration....

  18. Pushing the pace of tree species migration.

    Directory of Open Access Journals (Sweden)

    Eli D Lazarus

    Full Text Available Plants and animals have responded to past climate changes by migrating with habitable environments, sometimes shifting the boundaries of their geographic ranges by tens of kilometers per year or more. Species migrating in response to present climate conditions, however, must contend with landscapes fragmented by anthropogenic disturbance. We consider this problem in the context of wind-dispersed tree species. Mechanisms of long-distance seed dispersal make these species capable of rapid migration rates. Models of species-front migration suggest that even tree species with the capacity for long-distance dispersal will be unable to keep pace with future spatial changes in temperature gradients, exclusive of habitat fragmentation effects. Here we present a numerical model that captures the salient dynamics of migration by long-distance dispersal for a generic tree species. We then use the model to explore the possible effects of assisted colonization within a fragmented landscape under a simulated tree-planting scheme. Our results suggest that an assisted-colonization program could accelerate species-front migration rates enough to match the speed of climate change, but such a program would involve an environmental-sustainability intervention at a massive scale.

  19. Pushing the pace of tree species migration.

    Science.gov (United States)

    Lazarus, Eli D; McGill, Brian J

    2014-01-01

    Plants and animals have responded to past climate changes by migrating with habitable environments, sometimes shifting the boundaries of their geographic ranges by tens of kilometers per year or more. Species migrating in response to present climate conditions, however, must contend with landscapes fragmented by anthropogenic disturbance. We consider this problem in the context of wind-dispersed tree species. Mechanisms of long-distance seed dispersal make these species capable of rapid migration rates. Models of species-front migration suggest that even tree species with the capacity for long-distance dispersal will be unable to keep pace with future spatial changes in temperature gradients, exclusive of habitat fragmentation effects. Here we present a numerical model that captures the salient dynamics of migration by long-distance dispersal for a generic tree species. We then use the model to explore the possible effects of assisted colonization within a fragmented landscape under a simulated tree-planting scheme. Our results suggest that an assisted-colonization program could accelerate species-front migration rates enough to match the speed of climate change, but such a program would involve an environmental-sustainability intervention at a massive scale.

  20. Migrating to virtual technology with VAC

    Science.gov (United States)

    Jones, S. H.; Fay, R.; Bland, J.

    2017-10-01

    Traditional T2 grid sites still process large amounts of data flowing from the LHC and elsewhere. More flexible technologies, such as virtualisation and containerisation, are rapidly changing the landscape, but the right migration paths to these sunlit uplands are not well defined yet. We examine a recently developed migration route to virtual technology that is currently available to sites called VAC. We installed and tested VAC on a production class cluster and we ran it with a set of VOs for a period of months. We report our findings and conclude that VAC is suitable for large scale deployment.

  1. Migrating Art History

    DEFF Research Database (Denmark)

    Ørum, Tania

    2012-01-01

    Review of Hiroko Ikegami, The Great Migrator. Robert Rauschenberg and the Global Rise of American Art. Cambridge Mass., The MIT Press, 2010. 277 pages. ISBN 978-0-262-01425-0.......Review of Hiroko Ikegami, The Great Migrator. Robert Rauschenberg and the Global Rise of American Art. Cambridge Mass., The MIT Press, 2010. 277 pages. ISBN 978-0-262-01425-0....

  2. Migration in Burkina Faso

    NARCIS (Netherlands)

    Wouterse, F.S.

    2007-01-01

    Migration plays an important role in development and as a strategy for poverty reduction. A recent World Bank investigation finds a significant positive relationship between international migration and poverty reduction at the country level (Adams and Page 2003). Burkina Faso, whose conditions for

  3. Geography of European Migration

    Directory of Open Access Journals (Sweden)

    Zhitin Dmitry V.

    2016-08-01

    Full Text Available In recent decades, the role of international migration has increased dramatically in most European countries. The growth in migration has made some authors proclaim the beginning of a second Migration Period that could transform the social and cultural identity of Europe. The article presents an analysis of international migration geography in Europe in the last twenty-five years. The authors identify the main trends in migration, provide migration profiles of European countries, and propose a classification based on the recent changes in the migrant stock. Changes in the migrant stock (total emigration and immigration reflect the level of involvement in international and global processes. They can serve as an indicator of a country’s attractiveness for both foreigners and the country’s citizens. The study shows that European countries are increasingly split into ‘immigrant’ and ‘emigrant’ states. The authors describe spatial patterns of migration. The volume and localisation of migration flows in Europe are affected not only by cultural and historical circumstance, such as a colonial past or a common language. The scale of immigrant influx often does not depend on a donor country’s demographic potential or the level of its socio-economic development. The links between the place of origin and destination are often more complex than it might initially seem. The authors stress the importance of a differentiated immigration policy taking into account ethnic and cultural features of host societies.

  4. Migration, Narration, Identity

    DEFF Research Database (Denmark)

    Leese, Peter

    (co-editor with Carly McLaughlin and Wladyslaw Witalisz) This book presents articles resulting from joint research on the representations of migration conducted in connection with the Erasmus Intensive Programme entitled «Migration and Narration» taught to groups of international students over...

  5. The Globalisation of migration

    Directory of Open Access Journals (Sweden)

    Milan Mesić

    2002-04-01

    Full Text Available The paper demonstrates that contemporary international migration is a constitutive part of the globalisation process. After defining the concepts of globalisation and the globalisation of migration, the author discusses six key themes, linking globalisation and international migration (“global cities”, the scale of migration; diversification of migration flows; globalisation of science and education; international migration and citizenship; emigrant communities and new identities. First, in accordance with Saskia Sassen’s analysis, the author rejects the wide-spread notion that unqualified migrants have lost an (important role in »global cities«, i.e. in the centres of the new (global economy. Namely, the post-modern service sector cannot function without the support of a wide range of auxiliary unqualified workers. Second, a critical comparison with traditional overseas mass migration to the USA at the turn of the 19th and 20th centuries indicates that present international migration is, perhaps, less extensive – however it is important to take into consideration various limitations that previously did not exist, and thus the present migration potential is in really greater. Third, globalisation is more evident in a diversification of the forms of migration: the source area of migrants to the New World and Europe has expanded to include new regions in the world; new immigration areas have arisen (the Middle East, new industrial countries of the Far East, South Europe; intra-regional migration has intensified. Forth, globalisation is linked to an increased migration of experts and the pessimistic notion of a brain drain has been replaced by the optimistic idea of a brain gain. Fifth, contemporary international migration has been associated with a crisis of the national model of citizenship. Sixth, the interlinking of (migrant cultural communities regardless of distance and the physical proximity of cultural centres (the

  6. Migration and Environmental Hazards

    Science.gov (United States)

    Hunter, Lori M.

    2011-01-01

    Losses due to natural hazards (e.g., earthquakes, hurricanes) and technological hazards (e.g., nuclear waste facilities, chemical spills) are both on the rise. One response to hazard-related losses is migration, with this paper offering a review of research examining the association between migration and environmental hazards. Using examples from both developed and developing regional contexts, the overview demonstrates that the association between migration and environmental hazards varies by setting, hazard types, and household characteristics. In many cases, however, results demonstrate that environmental factors play a role in shaping migration decisions, particularly among those most vulnerable. Research also suggests that risk perception acts as a mediating factor. Classic migration theory is reviewed to offer a foundation for examination of these associations. PMID:21886366

  7. Migration of health workers.

    Science.gov (United States)

    Buchan, James

    2008-01-01

    The discussion and debate stimulated by these papers focused across a range of issues but there were four main areas of questioning: "measuring" and monitoring migration (issues related to comparability, completeness and accuracy of data sets on human resources); the impact of migration of health workers on health systems; the motivations of individual health workers to migrate (the "push" and "pull" factors) and the effect of policies designed either to reduce migration (e.g "self ufficiency") or to stimulate it (e.g active international recruitment). It was recognised that there was a critical need to examine migratory flows within the broader context of all health care labour market dynamics within a country, that increasing migration of health workers was an inevitable consequence of globalisation, and that there was a critical need to improve monitoring so as to better inform policy formulation and policy testing in this area.

  8. European migration: Push and pull

    National Research Council Canada - National Science Library

    Zimmermann, Klaus F

    1994-01-01

      In recent decades, Europe has experienced periods of push and pull migration. Whereas pull migration has been seen as economically beneficial, there is concern that push migration will accelerate the employment crisis...

  9. Modular knowledge systems accelerate human migration in asymmetric random environments.

    Science.gov (United States)

    Wang, Dong; Deem, Michael W

    2016-12-01

    Migration is a key mechanism for expansion of communities. In spatially heterogeneous environments, rapidly gaining knowledge about the local environment is key to the evolutionary success of a migrating population. For historical human migration, environmental heterogeneity was naturally asymmetric in the north-south (NS) and east-west (EW) directions. We here consider the human migration process in the Americas, modelled as random, asymmetric, modularly correlated environments. Knowledge about the environments determines the fitness of each individual. We present a phase diagram for asymmetry of migration as a function of carrying capacity and fitness threshold. We find that the speed of migration is proportional to the inverse complement of the spatial environmental gradient, and in particular, we find that NS migration rates are lower than EW migration rates when the environmental gradient is higher in the NS direction. Communication of knowledge between individuals can help to spread beneficial knowledge within the population. The speed of migration increases when communication transmits pieces of knowledge that contribute in a modular way to the fitness of individuals. The results for the dependence of migration rate on asymmetry and modularity are consistent with existing archaeological observations. The results for asymmetry of genetic divergence are consistent with patterns of human gene flow. © 2016 The Author(s).

  10. Migration and AIDS.

    Science.gov (United States)

    1998-01-01

    This article presents the perspectives of UNAIDS and the International Organization for Migration (IOM) on migration and HIV/AIDS. It identifies research and action priorities and policy issues, and describes the current situation in major regions of the world. Migration is a process. Movement is enhanced by air transport, rising international trade, deregulation of trade practices, and opening of borders. Movements are restricted by laws and statutes. Denial to freely circulate and obtain asylum is associated with vulnerability to HIV infections. A UNAIDS policy paper in 1997 and IOM policy guidelines in 1988 affirm that refugees and asylum seekers should not be targeted for special measures due to HIV/AIDS. There is an urgent need to provide primary health services for migrants, voluntary counseling and testing, and more favorable conditions. Research is needed on the role of migration in the spread of HIV, the extent of migration, availability of health services, and options for HIV prevention. Research must be action-oriented and focused on vulnerability to HIV and risk taking behavior. There is substantial mobility in West and Central Africa, economic migration in South Africa, and nonvoluntary migration in Angola. Sex workers in southeast Asia contribute to the spread. The breakup of the USSR led to population shifts. Migrants in Central America and Mexico move north to the US where HIV prevalence is higher.

  11. Migration of the population.

    Science.gov (United States)

    Krasinets, E

    1998-03-01

    Two factors influence foreign migration balance of the Russian Federation. The first factor involves the migration process between Russia and former union republics. The influx of population to the Russian Federation from other republics of the former Soviet Union is considered as one of the largest in the world. The average annual migratory growth of Russia during the years 1991-94 as a result of this migration exchange has tripled as compared with 1986-90, with a total of 2.7 million Russians who migrated into Russia. However, from 1996 up to the present time, the number of persons arriving in Russia declined dramatically. Meanwhile, the second factor that determines the country's migration balance is emigration to the far abroad. The most significant trend in determining the development of internal migration in Russia is the outflow of population from northern and eastern regions. The directions of internal and external migratory flows have a large influence on the migration balance in Russia's rural areas. The reduction of migratory flows in rural areas is the direct result of processes in the economic sphere. It confirms the reconstruction of rural-urban migratory exchange.

  12. Migration og etnicitet

    DEFF Research Database (Denmark)

    Christiansen, Connie Carøe

    2004-01-01

    Migration og etnicitet er aktuelle og forbundne fænomener, idet migration øger berøringsfladerne mellem befolkningsgrupper. Etniciteter formes i takt med at grænser drages imellem disse grupper. Imod moderniserings-teoriernes forventning forsvandt etnicitet ikke som en traditionel eller oprindelig...... måde at skabe tilhørsforhold på; globalt set fremstår vor tid istedet som en "migrationens tidsalder", der tilsyneladende også er en tidsalder, hvor kulturelle særtræk, i form af etnicitet, udgør vigtige linjer, hvorefter grupper skilller sig ud fra hinanden. Både migration og etnicitet bringer fokus...... den finder sted i modtagerlandet, men nyere perspektiver på migration, som begreber om medborgerskab, transnationalisme og diaspora er eksponenter for, søger udover den nationalstatslige ramme og inddrager konsekvenserne af migrationen for afsenderlande....

  13. Migration policy: from restriction to regulation.

    Science.gov (United States)

    Wu, Z

    1996-12-01

    This article describes the extent of rural-urban migration, the flows by province in 1992, and social policies relating to migration in China. Population movements followed several patterns: increased flows from rural-urban areas during 1945-66, reversed flows back to rural areas during the Cultural Revolution of 1966-77, and relaxed controls during 1978-87 and increased rural-urban migration. Migration policy began on a strict household registration system. Restrictions were eased to allow for regulation and allocation of surplus rural workers. Rapid industrial development helped China recover from the war. Peak movements were in 1958 during the "Great Leap Forward." An estimated 19 million rural workers were recruited during 1958-60. Supply of labor exceeded needs, and urban governments reversed this strategy in 1961. During the 1960s, the household registration system was strictly enforced. Urban population declined during 1965-76. Youth were required to reeducate themselves in farming areas. During 1978-87, China's central leadership established the household land-contract responsibility system and grain production increased. Limits on arable land resulted in surplus labor. In the mid-1980s, policy focused on nonagricultural wage labor in local factories. After 1988, the government encouraged development of cities and towns and village enterprises under the socialist market economy. It is likely that now the labor market rather than the household registration system will control the size, direction, and selectivity of migration.

  14. Migration transnationale des Vietnamiennes en Asie | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Au cours des dix dernières années, on a observé une croissance rapide de la féminisation de la migration en Asie. Durant cette période, plus de 100 000 Vietnamiennes ont migré vers d'autres pays pour travailler, et un nombre équivalent pour se marier, dans le cadre d'arrangements commerciaux. Souvent, cependant ...

  15. Runaway gas accretion and gap opening versus type I migration

    Science.gov (United States)

    Crida, A.; Bitsch, B.

    2017-03-01

    Growing planets interact with their natal protoplanetary disc, which exerts a torque onto them allowing them to migrate in the disc. Small mass planets do not affect the gas profile and migrate in the fast type-I migration. Although type-I migration can be directed outwards for planets smaller than 20 - 30M⊕ in some regions of the disc, planets above this mass should be lost into the central star long before the disc disperses. Massive planets push away material from their orbit and open a gap. They subsequently migrate in the slower, type II migration, which could save them from migrating all the way to the star. Hence, growing giant planets can be saved if and only if they can reach the gap opening mass, because this extends their migration timescale, allowing them to eventually survive at large orbits until the disc itself disperses. However, most of the previous studies only measured the torques on planets with fixed masses and orbits to determine the migration rate. Additionally, the transition between type-I and type-II migration itself is not well studied, especially when taking the growth mechanism of rapid gas accretion from the surrounding disc into account. Here we use isothermal 2D disc simulations with FARGO-2D1D to study the migration behaviour of gas accreting protoplanets in discs. We find that migrating giant planets always open gaps in the disc. We further show analytically and numerically that in the runaway gas accretion regime, the growth time-scale is comparable to the type-I migration time-scale, indicating that growing planets will reach gap opening masses before migrating all the way to the central star in type-I migration if the disc is not extremely viscous and/or thick. An accretion rate limited to the radial gas flow in the disc, in contrast, is not fast enough. When gas accretion by the planet is taken into account, the gap opening process is accelerated because the planet accretes material originating from its horseshoe region. This

  16. MODERN MIGRATION POLICY OF RUSSIA

    OpenAIRE

    Kobylinsky S. V.; Usenko A. S.

    2014-01-01

    Several peculiarities of the implementation of migration policy in the Russian Federation were considered in this article. We have shown main provisions on refugees and forced migrants from the Ukraine and labor migration. On the basis of the study we have suggested an improvement of migration legislation, in particular, creation of a single codex and migration police

  17. Mechanisms for fast cell migration in complex environments.

    Science.gov (United States)

    Vargas, Pablo; Barbier, Lucie; Sáez, Pablo José; Piel, Matthieu

    2017-10-01

    Cell migration depends on a combination of the cell's intrinsic capacity to move and the proper interpretation of external cues. This multistep process enables leukocytes to travel long distances in organs in just a few hours. This fast migration is partly due to the leukocytes' high level of plasticity, which helps them to adapt to a changing environment. Here, we review recent progress in understanding the mechanisms used by leukocytes to move rapidly and efficiently in intricate anatomical landscapes. We shall focus on specific cytoskeletal rearrangements used by neutrophils and dendritic cells to migrate within confined environments. Lastly, we will describe the properties that facilitate the rapid migration of leukocyte in complex tissue geometries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The challenges of rapid urbanization on sustainable development of ...

    African Journals Online (AJOL)

    The study examines the challenges of rapid urbanization on the sustainable development of Nyanya, Abuja. An interesting finding of the study is that the primary factor for the rapid urbanization of Nyanya within a short period of time is migration. The consequence of this rapid urbanization and population rise within a short ...

  19. Migration and health.

    Science.gov (United States)

    Evans, J; Baldwin, W

    1987-01-01

    Investigation of migration and health often forces us to acknowledge that the types of migration (international, internal, and residential) interact with each other as well as other population parameters such as the age/sex structure, sexual activity, fertility, mortality, and family structure. Research on migration is often obscured by these interactions. In fact, the adoption of a health perspective in the design of migration research represents a substantial improvement over traditional approaches that are based on distinctions among the various types of population movement. This is because a health perspective treats population movement as a dynamic process by which individuals are related to specific locations by reason of their participation in human networks. In other words, migration is regarded as a human process rather than a discrete event, and accordingly, it becomes less important to describe the individual's involvement with human networks and the institutions sustaining them. The use of a health perspective in migration research often calls our attention to the ways in which the types of migration are interconnected. For example, a migrant from Mexico might exhibit considerable internal mobility and may circulate between Mexico might exhibit considerable internal mobility and may circulate between Mexico and the US over several years until he develops enough contacts in the US to settle in a particular community in which his personal contact with human networks and place-specific institutions are conducive to settlement. Through him, family members may attach to the community. In the process, they all encounter health risks, make demands on the health care system, change the demographic/health characteristics of both sending and receiving places, sometimes act as transmitting agents of disease to those with whom they interact and, undergo changes in their levels of personal development and well-being. A research perspective that investigates these

  20. Migration = cloning; aliasiing

    DEFF Research Database (Denmark)

    Hüttel, Hans; Kleist, Josva; Nestmann, Uwe

    1999-01-01

    In Obliq, a lexically scoped, distributed, object-oriented programming language, object migration was suggested as the creation of a copy of an object’s state at the target site, followed by turning the object itself into an alias, also called surrogate, for the remote copy. We consider the creat......In Obliq, a lexically scoped, distributed, object-oriented programming language, object migration was suggested as the creation of a copy of an object’s state at the target site, followed by turning the object itself into an alias, also called surrogate, for the remote copy. We consider...... the creation of object surrogates as an abstraction of the abovementioned style of migration. We introduce Øjeblik, a distribution-free subset of Obliq, and provide three different configuration-style semantics, which only differ in the respective aliasing model. We show that two of the semantics, one of which...... matches Obliq’s implementation, render migration unsafe, while our new proposal for a third semantics is provably safe. Our work suggests a straightforward repair of Obliq’s aliasing model such that it allows programs to safely migrate objects....

  1. En fornemmelse for migration

    DEFF Research Database (Denmark)

    Schütze, Laura Maria

    Afhandlingen undersøger, hvordan sted, museets rolle som aktør og religion er relevante for produktionen af migration på Immigrantmuseet (2012) og i Københavns Museums udstilling At blive københavner (2010). Afhandlingen er baseret på udstillingsanalyse samt interview med relevant museumsfagligt......, anvendes som virkemidler til at nuancere migration og distancere udstillingen fra den offentlige debat om indvandring. Afhandlingen peger på, at produktionen af den nyere danske historie på museum er præget af et fravær af religion. Det skyldes, at de museumsfaglige praksisser og traditioner afspejler en...... identiteter, som vi tager for givet: nationer, byer, kvinder - såvel som migration og religion. Afhandlingen argumenterer følgelig for, at museernes produktion af (materiel) religion er et særdeles relevant, men kun ringe udforsket, genstandsfelt for religionssociologien....

  2. More myths of migration.

    Science.gov (United States)

    Basch, L; Lerner, G

    1986-01-01

    This paper discusses some of the myths of migration. The 5 myths presented are: 1) racism has little to do with the causes of migration and does not necessarily impede the adjustment or success of migrants; 2) in areas where there is a strong feminist movement and trade unions, migrant women receive their support and can count on the solidarity of these organizations; 3) transnational corporations are positive forces in the developing countries where they operate--not only do they provide these states with new sources of capital, but they also impart new industrial skills to the labor force; 4) migration today is essentially short-term in nature--it therefore does not have a strong impact on family life; and 5) most migrants cluster together in ethnic enclaves which provide a strong source of support and diminish dislocation inherent in the migrant process.

  3. Contextual background to the rapid increase in migration from ...

    African Journals Online (AJOL)

    user

    Brigade which was a North Korea-trained military outfit. The CCJP (1997) estimated that a total of 20 000 civilians were massacred in Matabeleland and the Midlands Provinces. Those targeted were accused of harbouring dissidents. Peace was only restored after the signing of the. Unity Accord between ZANU PF and ...

  4. Transventricular Migration of Neurocysticercosis.

    Science.gov (United States)

    Shah, Abhidha; Vutha, Ravikiran; Sankhe, Shilpa; Goel, Atul

    2017-09-01

    The movements of a neurocysticercosis cyst within the ventricular cavity have been identified rarely. A 22-year old male patient presented with the main symptom of diplopia for about a week. Findings of the neurologic examination revealed bilateral sixth cranial nerve weakness. Investigations during the period showed an intraventricular tumor that migrated from lateral ventricle to the third ventricle and subsequently to the fourth ventricle. The lesion was resected from the fourth ventricle and was identified to be a neurocysticercosis cyst. Such an intraventricular migration of any kind of tumor has not been recorded in the literature. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Migration, Narration, Identity

    DEFF Research Database (Denmark)

    Leese, Peter

    three consecutive summers from 2010 to 2012. The articles focus on various aspects of the migrant experience and try to answer questions about migrant identity and its representations in literature and the media. The book closes with an original play by Carlos Morton, the Chicano playwright working......(co-editor with Carly McLaughlin and Wladyslaw Witalisz) This book presents articles resulting from joint research on the representations of migration conducted in connection with the Erasmus Intensive Programme entitled «Migration and Narration» taught to groups of international students over...

  6. International Migration of Couples

    DEFF Research Database (Denmark)

    Junge, Martin; Munk, Martin D.; Nikolka, Till

    2018-01-01

    Migrant self-selection is important to labor markets and public finances in both origin and destination countries. We develop a theoretical model regarding the migration of dual-earner couples and test it using population-wide administrative data from Denmark. Our model predicts that the probabil......Migrant self-selection is important to labor markets and public finances in both origin and destination countries. We develop a theoretical model regarding the migration of dual-earner couples and test it using population-wide administrative data from Denmark. Our model predicts...

  7. Samtidskunst og migration

    DEFF Research Database (Denmark)

    Petersen, Anne Ring

    2010-01-01

    "Samtidskunst og migration. En oversigt over faglitteraturen" er en forskningsoversigt der gør status over hvad der hidtil er skrevet inden for det kunsthistoriske område om vor tids billedkunst og migration som politisk, socialt og kulturelt fænomen, primært i forbindelse med immigration til...... Europa og i bredere forstand Vesten. Rapporten er en intern rapport som er lavet i tilknytning til det kollektive forskningsprojekt "Islam i europæisk litteratur" på Afdelingen for Litteraturvidenskab og Moderne Kultur og indleveret til dette projekts leder, Peter Madsen....

  8. Making Migration Meaningful

    DEFF Research Database (Denmark)

    Benwell, Ann Fenger

    2013-01-01

    . The article focuses on changing patterns of mobility in the Mongolian ‘age of the market’ and its effects on population groups. Internal and international migration has continually risen as individuals and families have moved to places of opportunity. Connections are believed to be maintained during periods...... of absence by migrant family members, as both men and women are culturally permitted to be separate from their families. Migration is understood to contribute to prosperity, and separations contribute to generate growth and hishig (good fortune) for the good of the family. However, such mobility is also...

  9. Unix Application Migration Guide

    CERN Document Server

    Microsoft. Redmond

    2003-01-01

    Drawing on the experience of Microsoft consultants working in the field, as well as external organizations that have migrated from UNIX to Microsoft® Windows®, this guide offers practical, prescriptive guidance on the issues you are likely to face when porting existing UNIX applications to the Windows operating system environment. Senior IT decision makers, network managers, and operations managers will get real-world guidance and best practices on planning and implementation issues to understand the different methods through which migration or co-existence can be accomplished. Also detailing

  10. [Migration and diabetes].

    Science.gov (United States)

    Aydinkoc-Tuzcu, Kadriye; Schindler, Karin; Kautzky-Willer, Alexandra; Ludvik, Bernhard; Fasching, Peter

    2016-04-01

    The article deals with the demographic data of migration in Austria and with therapeutic advice concerning drug therapy and diabetes education for patients with migration background. In this context socio-cultural specifics are discussed. These suggestions are seen complementary to the general treatment guidelines of the Austrian Diabetes Association.Especially for the fast months Ramadan there are a lot of informations. The most important point is that the patient care must be highly individualized and the management plan may differ for each patient.

  11. What's driving migration?

    Science.gov (United States)

    Kane, H

    1995-01-01

    During the 1990s investment in prevention of international or internal migration declined, and crisis intervention increased. The budgets of the UN High Commissioner for Refugees and the UN Development Program remained about the same. The operating assumption is that war, persecution, famine, and environmental and social disintegration are inevitable. Future efforts should be directed to stabilizing populations through investment in sanitation, public health, preventive medicine, land tenure, environmental protection, and literacy. Forces pushing migration are likely to increase in the future. Forces include depletion of natural resources, income disparities, population pressure, and political disruption. The causes of migration are not constant. In the past, migration occurred during conquests, settlement, intermarriage, or religious conversion and was a collective movement. Current migration involves mass movement of individuals and the struggle to survive. There is new pressure to leave poor squatter settlements and the scarcities in land, water, and food. The slave trade between the 1500s and the 1800s linked continents, and only 2-3 million voluntarily crossed national borders. Involuntary migration began in the early 1800s when European feudal systems were in a decline, and people sought freedom. Official refugees, who satisfy the strict 1951 UN definition, increased from 15 million in 1980 to 23 million in 1990 but remained a small proportion of international migrants. Much of the mass movement occurs between developing countries. Migration to developed countries is accompanied by growing intolerance, which is misinformed. China practices a form of "population transfer" in Tibet in order to dilute Tibetan nationalism. Colonization of countries is a new less expensive form of control over territory. Eviction of minorities is another popular strategy in Iraq. Public works projects supported by foreign aid displace millions annually. War and civil conflicts

  12. Migration scenarii in extrasolar systems

    Directory of Open Access Journals (Sweden)

    Crida A.

    2011-02-01

    Full Text Available In this review talk, I present the theory of type I migration of small mass planets, and its latest developments that open the possibility of outward migration in the inner part of a protoplanetary disk. I also review the type II migration of giant planets, and mention the runaway, type III. Then, we focus on the migration of pairs of planets in resonance. The eccentricity of the planets raise, and possibly their mutual inclination as well. Also, the migration rate can be changed, and directed outward if the outer planet is the lighter. Last, we present a synthetic scenario of migration for the giant planets of our Solar System.

  13. Migration and regional inequality

    DEFF Research Database (Denmark)

    Peng, Lianqing; Swider, Sarah

    2017-01-01

    rising, regional inequality has actually decreased, and most recently, remained stable. Our study suggests that China’s unique migratory regime is crucial to understanding these findings. We conduct a counterfactual simulation to demonstrate how migration and remittances have mitigated income inequality...

  14. Migration as Adventure

    DEFF Research Database (Denmark)

    Olwig, Karen Fog

    2018-01-01

    Narratives of adventure constitute a well-established convention of describing travel experiences, yet the significance of this narrative genre in individuals’ accounts of their migration and life abroad has been little investigated. Drawing on Simmel and Bakhtin, among others, this article...

  15. Digitizing migration heritage

    DEFF Research Database (Denmark)

    Marselis, Randi

    2011-01-01

    Museums are increasingly digitizing their collections and making them available to the public on-line. Creating such digital resources may become means for social inclusion. For museums that acknowledge migration history and cultures of ethnic minority groups as important subjects in multiethnic...

  16. Diel vertical migrat..

    African Journals Online (AJOL)

    2002-01-24

    Jan 24, 2002 ... crustacean zooplankton but also in a Wide array of different marine zooplankton groups. (Russell 1927, McLaren 1963). Thus there is no doubt that ..... cooperation during field work and for their fruitful discussion on the draft manuscript. REFERENCES. Bayly lAE 1986 Aspects of diel vertical migration in ...

  17. Migration and Africa

    DEFF Research Database (Denmark)

    Zoppi, Marco

    2014-01-01

    European powers imposed the nation-state on Africa through colonialism. But even after African independencies, mainstream discourses and government policies have amplified the idea that sedentariness and the state are the only acceptable mode of modernity. Migration is portrayed as a menace...

  18. Describing migration spatial structure

    NARCIS (Netherlands)

    Rogers, A; Willekens, F; Little, J; Raymer, J

    The age structure of a population is a fundamental concept in demography and is generally depicted in the form of an age pyramid. The spatial structure of an interregional system of origin-destination-specific migration streams is, however, a notion lacking a widely accepted definition. We offer a

  19. Migrating the Light

    DEFF Research Database (Denmark)

    Sørensen, Bent

    The migration of Blaga’s universalist, even centralist poems from Romanian of the first third of the 20th C. into American of the first fifth of the 21st C. illustrates the uses of Pierre Joris’s nomadic methods. My translations of Blaga read well for a teenage audience whose only exposure to lit...

  20. Practical Data Migration

    CERN Document Server

    Morris, Johny

    2012-01-01

    This book is for executives and practitioners tasked with the movement of data from old systems to a new repository. It uses a series of steps guaranteed to get the reader from an empty new system to one that is working and backed by the user population. Using this proven methodology will vastly increase the chances of a successful migration.

  1. From Migration Regime to Regional Citizenry: Migration and Identity ...

    African Journals Online (AJOL)

    I examine the East African common market, taken as a regional migration regime, and draw its implications for intra-regional migration and identity formation. Using desk research, I analyse the common market Protocol's provisions and envisage the implications of its implementation for intraregional migration and identity ...

  2. The International Organization for Migration in Global Migration Governance

    OpenAIRE

    Poulsen, Sofie Havn; Andersen, Lise

    2011-01-01

    This project focuses on the IOM, the notion of global governance of migration and the interaction between these two. The point of departure has been an attempt to grasp the current global approach to migration and comprehend whether, or to what degree, there is governance of migration issues taking place at a global level.

  3. Rapid Prototyping

    Science.gov (United States)

    1999-01-01

    Javelin, a Lone Peak Engineering Inc. Company has introduced the SteamRoller(TM) System as a commercial product. The system was designed by Javelin during a Phase II NASA funded small commercial product. The purpose of the invention was to allow automated-feed of flexible ceramic tapes to the Laminated Object Manufacturing rapid prototyping equipment. The ceramic material that Javelin was working with during the Phase II project is silicon nitride. This engineered ceramic material is of interest for space-based component.

  4. Zimbabwe's Exodus Crisis, Migration, Survival

    International Development Research Centre (IDRC) Digital Library (Canada)

    Remittances, Informalisation and Dispossession in Urban Zimbabwe Sarah Bracking and Lloyd Sachikonye. 324. Chapter Fifteen Transnationalism and Undocumented Migration Between Rural Zimbabwe and South Africa France Maphosa. 346. Chapter Sixteen Metaphors of Migration: Zimbabwean Migrants in the South ...

  5. [Migration processes in small towns].

    Science.gov (United States)

    Makowska, K

    1988-10-01

    Changing migration patterns in Poland and their impact on small towns are analysed with a focus on the period since the 1950s. The analysis shows that although migration previously benefited major urban areas at the expense of small towns, the migration situation of small towns has recently improved.

  6. Migration of cells in a social context

    DEFF Research Database (Denmark)

    Vedel, Søren; Tay, Savas; Johnston, Darius M

    2013-01-01

    In multicellular organisms and complex ecosystems, cells migrate in a social context. Whereas this is essential for the basic processes of life, the influence of neighboring cells on the individual remains poorly understood. Previous work on isolated cells has observed a stereotypical migratory...... based on the experimentally identified "cellular traffic rules" and basic physics that revealed that these emergent behaviors are caused by the interplay of single-cell properties and intercellular interactions, the latter being dominated by a pseudopod formation bias mediated by secreted chemicals...... and pseudopod collapse following collisions. The model demonstrates how aspects of complex biology can be explained by simple rules of physics and constitutes a rapid test bed for future studies of collective migration of individual cells....

  7. Metropolitan migration and population growth in selected developing countries.

    Science.gov (United States)

    1983-01-01

    The purpose of this article is to estimate the components of metropolitan population growth in selected developing countries during 1960-1970 period. The study examines population growth in 26 cities: 5 are in Africa, 8 in Asia, and 13 in Latin America, using data from national census publications. These cities in general are the political capitals of their countries, but some additional large cities were selected in Brazil, Mexico, and South Africa. All cities, at the beginning of the 1960-1970 decade had over 500,000 population; Accra, the only exception, reached this population level during the 1960s. Some cities had over 4 million residents in 1970. Net migration contributed about 37% to total metropolitan population growth; the remainder of the growth is attributable to natural increase. Migration has a much stronger impact on metropolitan growth than suggested by the above figure: 1) Several metropolitan areas, for various reasons, are unlikely to receive many migrants; without those cities, the share of metropolitan growth from net migration is 44%. 2) Estimates of the natural increase of migrants after their arrival in the metropolitan areas, when added to migration itself, changes the total contribution of migration to 49% in some metropolitan areas. 3) Even where net migration contributes a smaller proportion to metropolitan growth than natural increase, the rates of net migration are generally high and should be viewed in the context of rapid metropolitan population growth from natural increase alone. Finally, the paper also compares the components of metropolitan growth with the components of growth in the remaining urban areas. The results show that the metropolitan areas, in general, grow faster than the remaining urban areas, and that this more rapid growth is mostly due to a higher rate of net migration. Given the significance of migration for metropolitan growth, further investigations of the effects of these migration streams, particularly with

  8. Musei del migration heritage / Migration heritage museums

    Directory of Open Access Journals (Sweden)

    Patrizia Dragoni

    2015-01-01

    Since the second half of the 1960s of the 20th century, a profound cultural innovation was accompanied to the radical change in the social, political and economic climate. The anthropological notion of culture as opposed to idealistic vision, the unusual and strong interest in material culture, the enunciation of the concept of cultural property by the Franceschini Commission, the luck of the Public History bring a change of the disciplinary statutes of historical sciences, which begin to attend to social history, focusing on the spontaneous sources of information and initiating experiences of oral history. To all this a remarkable transformation of the themes and of the social function of museums is added. This paper illustrates, in relation to this more general context, the foundation and the dissemination of museums dedicated to the history of migration in Italy and in the world, enunciates their possible social utility for the integration of present migrants in Italy and illustrates, by way of example, the museum recently opened in Recanati.

  9. [Medical genetics and migration].

    Science.gov (United States)

    Feingold, J

    1988-01-01

    Any migration results in the transfer of normal and pathological genes from one population to another. The frequency of pathological genes may vary according to the population, sickle cell anaemia, for instance, being frequent in Africa and cystic fibrosis in Europe. It follows that the hereditary pathology of migrants is not the same as that of the host population, at least during the immediate post-migration years; subsequently, all depends on the degree of cross-breeding. In epidemiological genetics the study of the frequency of some diseases in the original population, among migrants and in the host population enables the effects of genes and environment on the aetiology of these diseases to be investigated.

  10. Tracking migrating birds

    DEFF Research Database (Denmark)

    Willemoes, Mikkel

    Migratory movements of birds has always fascinated man and led to many questions concerning the ecological drivers behind, the necessary adaptations and the navigational abilities required. However, especially for the long-distance migrants, basic descriptions of their movements are still lacking...... and many experiments are only becoming possible with the current development of tracking technologies. During this thesis work I have been tracking the poorly known movements of several species of long-distance migrants and document highly complex migration patterns. In three manuscripts these movements...... were related to the yearly progression of an environmental surrogate for food availability along the course of migration. In one species, with multiple, different non-breeding staging sites, environmental conditions explain movements well and also how yearly differences explain differences in timing...

  11. Religion, migration og integration

    DEFF Research Database (Denmark)

    Borup, Jørn

    2010-01-01

    Sammenhængen mellem religion og integration har de sidste år været genstand for debat. Artiklen kommer ind på begreber og sammenhænge relateret til området (migration, diaspora, assimilation, etnicitet, kultur) og ser på religionens mulige rolle som negativ eller positiv ressource i integrationss......Sammenhængen mellem religion og integration har de sidste år været genstand for debat. Artiklen kommer ind på begreber og sammenhænge relateret til området (migration, diaspora, assimilation, etnicitet, kultur) og ser på religionens mulige rolle som negativ eller positiv ressource i...

  12. Forced Migration: Refugee Populations

    Science.gov (United States)

    Boyle, Joyceen S.

    2015-01-01

    Undocumented migration is a global phenomenon that manifests in various contexts. This article describes the impact of the movement of large numbers of people in several African countries, producing a unique type of migrant—the refugee. We describe issues that refugee movements create on fragile health care systems, situations that precipitate refugee movements, certain human rights violations that are of particular concern such as gender based violence (GBV) and child soldiers, and lastly, implications for nursing practice and policy. We use examples from several countries in Sub-Saharan Africa, including the Democratic Republic of the Congo, Rwanda, Liberia, Sierra Leone, and Mozambique. Drawing on key documents from the United Nations High Commissioner for Refugees, current literature, as well as the international experience of the authors, this article presents an overview of forced migration and discusses opportunities for nurses to impact research, practice and policy related to refugee health. PMID:25645484

  13. Syrian Crisis and Migration

    OpenAIRE

    Pinar Yazgan; Deniz Eroglu Utku; Ibrahim Sirkeci

    2015-01-01

    With the growing insurrections in Syria in 2011, an exodus in large numbers have emerged. The turmoil and violence have caused mass migration to destinations both within the region and beyond. The current "refugee crisis" has escalated sharply and its impact is widening from neighbouring countries toward Europe. Today, the Syrian crisis is the major cause for an increase in displacement and the resultant dire humanitarian situation in the region. Since the conflict shows no signs of abating i...

  14. Retrograde Gastrojejunostomy Tube Migration

    Directory of Open Access Journals (Sweden)

    Adeleke Adesina

    2014-01-01

    Full Text Available Percutaneous enteral feeding tubes are placed about 250,000 times each year in the United States. Although they are relatively safe, their placement may be complicated by perforation, infection, bleeding, vomiting, dislodgment, and obstruction. There have been numerous reports of antegrade migration of gastrojejunostomy (G-J tubes. We report a case of G-J tube regurgitation following protracted vomiting and discuss the management of this very rare entity.

  15. American Migration Controversies

    OpenAIRE

    Milan Mesić

    1998-01-01

    The USA has been and has remained the world's most important immigration country. The last quarter of the 20th century has been marked by a new mass immigration wave that in absolute size of the immigration flow can be compared to the highest flows in the previous century. This recent migration, however, differs from traditional immigration to America in that it includes a greater ethnic, religious and cultural diversity. The vast majority of today's immigrants, both legal and clandestine, co...

  16. Enforcement and illegal migration

    OpenAIRE

    Pia Orrenius

    2014-01-01

    Border enforcement of immigration laws attempts to raise the costs of illegal immigration, while interior enforcement also lowers the benefits. Border and interior enforcement therefore reduce the net benefits of illegal immigration and should lower the probability that an individual will decide to migrate. While some empirical studies find that border and interior enforcement serve as significant deterrents to illegal immigration, immigration enforcement is costly and carries significant uni...

  17. Conservation physiology of animal migration

    Science.gov (United States)

    Lennox, Robert J.; Chapman, Jacqueline M.; Souliere, Christopher M.; Tudorache, Christian; Wikelski, Martin; Metcalfe, Julian D.; Cooke, Steven J.

    2016-01-01

    Migration is a widespread phenomenon among many taxa. This complex behaviour enables animals to exploit many temporally productive and spatially discrete habitats to accrue various fitness benefits (e.g. growth, reproduction, predator avoidance). Human activities and global environmental change represent potential threats to migrating animals (from individuals to species), and research is underway to understand mechanisms that control migration and how migration responds to modern challenges. Focusing on behavioural and physiological aspects of migration can help to provide better understanding, management and conservation of migratory populations. Here, we highlight different physiological, behavioural and biomechanical aspects of animal migration that will help us to understand how migratory animals interact with current and future anthropogenic threats. We are in the early stages of a changing planet, and our understanding of how physiology is linked to the persistence of migratory animals is still developing; therefore, we regard the following questions as being central to the conservation physiology of animal migrations. Will climate change influence the energetic costs of migration? Will shifting temperatures change the annual clocks of migrating animals? Will anthropogenic influences have an effect on orientation during migration? Will increased anthropogenic alteration of migration stopover sites/migration corridors affect the stress physiology of migrating animals? Can physiological knowledge be used to identify strategies for facilitating the movement of animals? Our synthesis reveals that given the inherent challenges of migration, additional stressors derived from altered environments (e.g. climate change, physical habitat alteration, light pollution) or interaction with human infrastructure (e.g. wind or hydrokinetic turbines, dams) or activities (e.g. fisheries) could lead to long-term changes to migratory phenotypes. However, uncertainty remains

  18. Migration Profile NIGERIA 1. Structural Migration Profile 2. Flash Migration Profile (January - March 2017)

    OpenAIRE

    BRYTON DIAS MARQUES FERNANDO; URSO GIULIANA

    2017-01-01

    The new generation of Migration Profiles aims at collecting knowledge on migration and development at regular, short intervals (3/6 months) and with a sub-national coverage, providing tailored monitoring and ensuring comparability across countries. It links migration, developmental and humanitarian aspects as well as analyses on the EU strategic role vis-à-vis the third country, including its political, financial and humanitarian support. This publication reproduces the Migration Profile of N...

  19. Many Faces of Migrations

    Directory of Open Access Journals (Sweden)

    Milica Antić Gaber

    2013-12-01

    We believe that in the present thematic issue we have succeeded in capturing an important part of the modern European research dynamic in the field of migration. In addition to well-known scholars in this field several young authors at the beginning their research careers have been shortlisted for the publication. We are glad of their success as it bodes a vibrancy of this research area in the future. At the same time, we were pleased to receive responses to the invitation from representatives of so many disciplines, and that the number of papers received significantly exceeded the maximum volume of the journal. Recognising and understanding of the many faces of migration are important steps towards the comprehensive knowledge needed to successfully meet the challenges of migration issues today and even more so in the future. It is therefore of utmost importance that researchers find ways of transferring their academic knowledge into practice – to all levels of education, the media, the wider public and, of course, the decision makers in local, national and international institutions. The call also applies to all authors in this issue of the journal.

  20. Social effects of migration in receiving countries.

    Science.gov (United States)

    Ohndorf, W

    1989-06-01

    This paper examines the impact of post-1945 migration into Western, Middle, and Northern Europe from Southern Europe, Turkey, and Northern Africa, and migration to the traditional immigration countries by Asian and Latin American immigrants, on the social structures of receiving countries. Between 1955 and 1974, 1) traditional migration to the US and Australia became less important for European countries while traditional receiving countries accepted many immigrants from developing countries; and 2) rapid economic revival in Western and Northern Europe caused a considerable labor shortage which was filled by migrant workers especially from Southern Europe, Turkey, and Northern Africa, who stayed only until they reached their economic goals. Since 1974, job vacancies have declined and unemployment has soared. This employment crisis caused some migrants 1) to return to their countries of origin, 2) to bring the rest of their families to the receiving country, or 3) to lengthen their stay considerably. The number of refugees has also significantly increased since the mid-970s, as has the number of illegal migrants. After the mid-1970s, Europe began to experience integration problems. The different aspects of the impact of migration on social structures include 1) improvement of the housing situation for foreigners, 2) teaching migrants the language of the receiving country, 3) solving the unemployment problem of unskilled migrants, 4) improvement of educational and vocational qualifications of 2nd generation migrants, 5) development of programs to help unemployed wives of migrants to learn the language and meet indigenous women, 6) encouraging migrants to maintain their cultural identity and assisting them with reintegration if they return to their original country, 7) coping with the problems of refugees, and 8) solving the problems of illegal migration. Almost all receiving countries now severely restrict further immigration. [Those policies should result in

  1. Migrations in Slovenian geography textbooks

    Directory of Open Access Journals (Sweden)

    Jurij Senegačnik

    2013-12-01

    Full Text Available In Slovenia, the migrations are treated in almost all geographical textbooks for different levels of education. In the textbooks for the elementary school from the sixth to ninth grade, students acquire knowledge of the migrations by the inductive approach. Difficulty level of treatment and quantity of information are increasing by the age level. In the grammar school program a trail of gaining knowledge on migration is deductive. Most attention is dedicated to migrations in general geography textbooks. The textbooks for vocational and technical school programs deal with migrations to a lesser extent and with different approaches.

  2. Physical Guidance of Cell Migration

    Science.gov (United States)

    Losert, Wolfgang

    Cells migrate as individuals or groups, to perform critical functions in life from organ development to wound healing and the immune response. While directed migration of cells is often mediated by chemical or physical gradients, our recent work has demonstrated that the physical properties of the microenvironment can also control and guide migration. I will describe how an underlying wave-like process of the actin scaffolding drives persistent migration, and how such actin waves are nucleated and guided by the texture of the microenvironment. Based on this observation we design textures capable of guiding cells in a single preferred direction using local asymmetries in nano/microtopography on subcellular scales, or altering migration in other ways. This phenomenon is observed both for the pseudopod-dominated migration of Dictyostelium cells and for the lamellipod-driven migration of human neutrophils. The conservation of this mechanism across cell types suggests that actin-wave-based guidance is important in biology and physiology.

  3. Migration, Business Formation, and the Informal Economy in Urban Mexico

    Science.gov (United States)

    Riosmena, Fernando

    2013-01-01

    Although the informal economy has grown rapidly in several developing nations, and migration and informality may be related to similar types of credit constraints and market failures, previous research has not systematically attempted to identify if migrant households are more likely to start informal and formal businesses alike and if this association varies across local contexts. We examine the relationship between prior U.S. migration and the creation of both formal and informal businesses in urban Mexico using several criteria to indirectly assess sector location. We use data from 56 communities from the Mexican Migration Project to estimate multilevel survival and nonmultilevel competing risk models predicting the likelihood of informal, formal, and no business formation. The recent return migration of the household head is strongly associated with informal business creation, particularly in economically dynamic areas. On the other hand, migrants are only marginally more likely to start formal businesses in highly economically dynamic sending areas. PMID:23721676

  4. Migration, business formation, and the informal economy in urban Mexico.

    Science.gov (United States)

    Sheehan, Connor M; Riosmena, Fernando

    2013-07-01

    Although the informal economy has grown rapidly in several developing nations, and migration and informality may be related to similar types of credit constraints and market failures, previous research has not systematically attempted to identify if migrant households are more likely to start informal and formal businesses alike and if this association varies across local contexts. We examine the relationship between prior US migration and the creation of both formal and informal businesses in urban Mexico using several criteria to indirectly assess sector location. We use data from 56 communities from the Mexican Migration Project to estimate multilevel survival and nonmultilevel competing risk models predicting the likelihood of informal, formal, and no business formation. The recent return migration of the household head is strongly associated with informal business creation, particularly in economically dynamic areas. On the other hand, migrants are only marginally more likely to start formal businesses in highly economically dynamic sending areas. Published by Elsevier Inc.

  5. Seismic depth migration using the Gabor imaging theories

    Science.gov (United States)

    Ma, Yongwang

    2009-12-01

    Seismic depth migrations are used to image the earth with more plausible details; they become important tools to obtain 'true' pictures of the subsurface and attract more and more attention. This thesis is dedicated to developing a wave-equation depth migration method, called Gabor depth migration, where the Gabor transform is employed. The Gabor depth migration method is developed to image structures with strong lateral velocity variations. The wavefield is localized by narrow and uniform partitions such that the most rapidly varying velocity can be accommodated to get accurate images. However, such narrow and uniform partitions introduce inefficient depth migrations, which is not always necessary. Instead, wide and optimized partitions should be utilized according to lateral velocity variations given accuracy criteria. Adaptive partitioning algorithms are developed to consolidate narrow, small partitions where lateral variations are considered as minor given accuracy criteria. Such a consolidation process usually results in fewer and wider partitions, leading to fewer Fourier transforms in the wavefield extrapolation. Therefore, computational cost is minimized under given accuracy thresholds. Three adaptive partitioning algorithms described in this thesis help to achieve efficient Gabor depth migrations at the cost of losing some imaging accuracy. The Gabor depth migration method can achieve accurate images by increasing accuracy thresholds. An optimized imaging process can be obtained by using trade-off between efficiency and accuracy in the migration method. The Gabor depth migration method is made more efficient using the spatial resampling without losing imaging accuracy. The depth migration method reduces computational cost by down-sampling wavefields at low frequencies, giving a faster imaging process. Depth images from the Marmousi data verify the improvement of migration speed without obvious loss of imaging quality. In addition, the Gabor depth migration

  6. Simulation of Complex Tremor Migration Patterns

    Science.gov (United States)

    Luo, Y.; Ampuero, J. P.

    2012-12-01

    The discovery of slow-slip events (SSE) and non-volcanic tremors has greatly enriched the spectrum of earthquake behavior and offers a unique window into the mechanics of the deeper portion of the seismogenic zone of active faults, an uncharted region of great importance in the nucleation of large earthquakes. In Northern Cascadia, tremors show an intriguing hierarchy of migration patterns: large-scale tremor migrating along-strike at about 10 km/day, sparsely distributed swarms that propagate 10 times faster in the opposite direction ('rapid tremor reversals' or RTRs) and even 10 times faster swarms that propagate along-dip. Moreover, during the initial phase of ETS (Episodic Tremor and Slip) the tremor source amplitude shows a linear growth and up-dip propagation. We have proposed a model to reproduce these observations based on interaction of brittle asperities (frictionally unstable, velocity-weakening patches) embedded in a relatively stable fault, mediated by creep transients. We continue quantitative studies of this model through numerical simulations of heterogeneous rate-and-state faults under the Quasi-DYNamic approximation (open-source software project QDYN, hosted online at http://code.google.com/p/qdyn/). We performed both 2D and 3D simulations and successfully reproduced all the major phenomena of complex tremor migration patterns (forward migration, RTRs and along-dip swarms). We will show a complete analysis of friction properties and geometrical settings (i.e. asperity size, distance, etc.) that affects spatial-temporal distribution and migration velocity of tremors. Our study shows that by decreasing the distance between asperities or by increasing the value of (a-b)*sigma inside them, both RTR migration velocity and distance increase positively correlated, and the proportion of moment released seismically during the ETS increases, while the ratio of RTR versus forward tremor migration speed remains mostly the same. While the density of these deep

  7. CD31 regulates direction and rate of neutrophil migration over and under endothelial cells.

    Science.gov (United States)

    Luu, N Thin; Rainger, G Ed; Buckley, Christopher D; Nash, Gerard B

    2003-01-01

    Mechanisms guiding migration of neutrophils through endothelium are poorly understood. We showed previously that CD31-CD31 binding acted as an 'accelerator' for neutrophils migrating on platelets, while neutrophil alpha(v)beta3-integrin acted as a sensor to align migration with the direction of imposed flow. Here, we perfused neutrophils over human umbilical vein endothelial cells (HUVEC) treated with tumour necrosis factor-alpha, and characterised the kinetics of migration over, through and underneath the HUVEC. Before penetrating the monolayer, activated neutrophils migrated relatively slowly over the surface (approximately 6 microm/min), preferentially in the direction of flow. Once transmigrated, neutrophils moved more rapidly (approximately 14 microm/min) without preferred direction. Treatment of HUVEC and/or neutrophils with function-blocking antibodies against CD31 reduced directionality but not velocity of migration on top of HUVEC, and reduced velocity of migration underneath the monolayer. If neutrophils were pre-activated with formyl peptide, they did not migrate through the HUVEC, but migrated with increased velocity and directionality on top. Under these circumstances, both velocity and directionality were reduced by blocking CD31. alpha(v)beta3-integrin did not regulate migration under any conditions. We conclude that CD31-CD31 bonds act as robust sensors which can guide neutrophil migration, and also modify its velocity. Thus mechanical and adhesive signals can regulate neutrophil migration driven by locally-acting chemotactic agents. Copyright 2003 S. Karger AG, Basel

  8. Landbird migration in riparian habitats of the Middle Rio Grande: A case study

    Science.gov (United States)

    Deborah M. Finch; Wang Yang

    2000-01-01

    Growing human populations and rapid ecological changes threaten the sustainability of the middle Rio Grande, a river corridor important to numerous species of wintering, breeding, and migrating waterfowl, shorebirds, and songbirds. We review the vegetational and human history of the middle Rio Grande, substantiate the importance of this system to landbirds in migration...

  9. Research on Migration in Africa: Past, Present, and Future, African Rural Employment Paper No. 2.

    Science.gov (United States)

    Byerlee, Derek

    African nations have been experiencing rapid rates of urbanization accompanied by serious problems of urban unemployment due to the rate of rural-urban migration and the lack of an adequate understanding of the migration process for economic policy formulation. The aim of this paper was to review the present knowledge of African rural-urban…

  10. ILO - International Migration Programme.

    Science.gov (United States)

    Boudraa, Miriam

    2011-01-01

    In a wide International Context characterised not only by the economical development but also by the social, cultural, political and individual development, we witness more and more to a exchange between the developed and the developing countries, which can be translated especially in the migration of the work force. In theory, all countries are either countries of origin either countries of transit or destination, and they are all responsible for the rights of migrant workers by promoting the rights, by monitoring and by preventing the abusive conditions. The process of migration of the workforce can be divided into three stages: the first coincides with the period prior to departure, the second is represented by the aftermath of the departure and the period of stay in the country of destination, the third stage corresponds to the return in the country of origin. The workers must be protected throughout this process by the international organizations that perform the catalytic role of communication and exchange between countries, for the only purpose of protecting the rights of immigrant and/or immigrants workers. The responsibility for the protection of workers is divided among the various players in the International Labour Organisation. Every country has to apply measures according to the international standards regarding workers' rights, standards that guide the various countries in the formulation and implementation of their policies and legislation. These standards are suggested by International Conventions, the ILO Conventions and other international instruments such as the human rights instrument. There has been a big step forward once the ILO Fundamental Conventions and Conventions on Migrant Workers where implemented and this implementation represented the use of the Guidelines "ILO Multilateral Framework on Labour Migration".

  11. International Migration of Couples

    OpenAIRE

    Junge, Martin; Munk, Martin D.; Nikolka, Till; Poutvaara, Panu

    2017-01-01

    We analyze emigration and return decisions of Danish couples. Our main questions are how emigration and return migration decisions depend on education, earnings, and the number and age of children. We use register data on full population from 1982 to 2006, focusing on opposite-gender couples in which the female is aged 23 to 37, and the male 25 to 39. We find that power couples in which both are highly educated are most likely to emigrate, but also most likely to return. Couples in which only...

  12. Globalization, migration and health.

    Science.gov (United States)

    Burnett, Angela

    2002-01-01

    The term 'globalization' describes the integration of economic systems through improved communication, but it also represents increased insecurity for those with few resources--particularly refugees. This article examines why people migrate, their numbers, constraints on their movement and their particular health care needs. Immigrants have much to contribute to their recipient countries, but at some loss to their homelands. Both economically and morally, more liberal immigration policies would be beneficial. Policies towards asylum seekers should not be more restrictive in the aftermath of 11 September 2001 and detention should be the exception rather than the rule. Globalization should be managed so as to improve people's lives throughout the world.

  13. [Obesity, migration and adolescence].

    Science.gov (United States)

    Chamay-Weber, Catherine; Shehu-Brovina, Shqipe; Narring, Françoise

    2012-06-13

    Weight management interventions during adolescence are challenging. Migration adds complexity to this problem, making migrant families more vulnerable. Teenagers confront families to new values transmitted by the host society: opulence, junk food, video games. Obesity should not be seen as a single issue of calories-excess, but must be considered as being part of a larger problem, which takes into account the context of the familial and societal life of the migrants. The caregivers must have an overall view of the situation to provide appropriate approaches to weight management.

  14. Urbanization, Migration, Information

    Directory of Open Access Journals (Sweden)

    Konstantin Lidin

    2016-05-01

    Full Text Available In the contemporary world urbanization becomes a large-scale process. Huge flows of people migrate from poorer districts to the cities with a higher level of consumption. It takes migrants about 15-25 years to give up their traditional ascetic way of life. In this period the ‘new citizens’ try to arrange compact settlements with an archaic way of life, insanitary conditions, high criminogenity and an authoritative local self-government. The processes of formation and decay of the ascetic enclave are viewed through the example of the ‘Shanghai’ trading neighborhood in Irkutsk.

  15. Migration and loving

    OpenAIRE

    Gevrek, Deniz

    2010-01-01

    This paper explores the relationship between anti-miscegenation laws, interracial marriage and black males' geographical distribution in the U.S. during and after the Great Migration. The U.S. Supreme Court decision in the case of Loving v. Virginia in 1967, which forced the last 16 Southern states to strike down their anti-miscegenation laws, creates a unique opportunity to explore the impact of an exogenous change in a state's laws regulating interracial marriages. Analyzing the U.S. Census...

  16. Palaearctic-African Bird Migration

    DEFF Research Database (Denmark)

    Iwajomo, Soladoye Babatola

    Bird migration has attracted a lot of interests over past centuries and the methods used for studying this phenomenon has greatly improved in terms of availability, dimension, scale and precision. In spite of the advancements, relatively more is known about the spring migration of trans......-Saharan migrants than autumn migration. Information about the behavior and interactions of migrants during the nonbreeding season in sub-Saharan Africa is also scarce for many species. Furthermore, very little is known about intra-African migration. This thesis summarizes my research on the autumn migration...... of birds from Europe to Africa and opens up the possibility of studying intra-African migration. I have used long-term, standardized autumn ringing data from southeast Sweden to investigate patterns in biometrics, phenology and population trends as inferred from annual trapping totals. In addition, I...

  17. Network migration for printers

    CERN Multimedia

    2016-01-01

    Further to the recent General Purpose (office) Network reorganisation (as announced in the Bulletin - see here), please note that the majority of print devices will be automatically migrated to the new network IP address range on Tuesday 27 September.   This change should be transparent for these devices and therefore end-users, provided you have installed the printers from the Print Service website. A small number of devices will require manual intervention from the Printer Support team in order to migrate correctly. These devices will not change their IP address until the manual intervention, which will be carried out before Monday 3rd October. However, if you have mistakenly connected directly to the printer’s IP address, then your printing will be affected – please uninstall the printer (for help, see: KB3785), and re-install it from the Print Service website (or follow instructions for visitor machines). Please do this as soon as possible in order to avoid printing issues, t...

  18. Circular Migration and Human Development

    OpenAIRE

    Newland, Kathleen

    2009-01-01

    This paper explores the human development implications of circular migration — both where it occurs naturally and where governments work to create it. The paper discusses various conceptions and definitions of circular migration, and concludes that circular migration is not intrinsically positive or negative in relation to human development; its impact depends upon the circumstances in which it occurs, the constraints that surround it and—above all—the degree of choice that individuals can ex...

  19. The challenges of managing migration

    Energy Technology Data Exchange (ETDEWEB)

    Tacoli, Cecilia

    2005-10-15

    Migration and urbanisation are driven by economic growth and social change, but also by deepening inequalities. Managing migration should not be equated with curbing it, as this inevitably reduces migrants' rights. But managing population movement whilst respecting the rights of migrants and nonmigrants, supporting the contribution of migration to poverty reduction and economic growth in sending and receiving areas and reducing the human and material costs of movement means that fundamental challenges need to be addressed.

  20. Macrostabilization of the Migration Phenomenon

    Directory of Open Access Journals (Sweden)

    Cristina Burghelea

    2014-03-01

    Full Text Available MacLabour migration is a present phenomenon in the European Union. This phenomenon takes over the entire European continent, but especially in the EU countries. The labor market in Europe is increasingly affected by population aging. Economic differences between European countries make workforce in developing countries to move to developed countries where they find it easier to work and receive higher remuneration than in their home countries. This article tracks labor migration from/to EU, employment in Romania and Romanian migration towards the countries of Western Europe. It also presents statistics on labor migration in the EU and its impact on the labor market

  1. Substrate curvature regulates cell migration.

    Science.gov (United States)

    He, Xiuxiu; Jiang, Yi

    2017-05-23

    Cell migration is essential in many aspects of biology. Many basic migration processes, including adhesion, membrane protrusion and tension, cytoskeletal polymerization, and contraction, have to act in concert to regulate cell migration. At the same time, substrate topography modulates these processes. In this work, we study how substrate curvature at micrometer scale regulates cell motility. We have developed a 3D mechanical model of single cell migration and simulated migration on curved substrates with different curvatures. The simulation results show that cell migration is more persistent on concave surfaces than on convex surfaces. We have further calculated analytically the cell shape and protrusion force for cells on curved substrates. We have shown that while cells spread out more on convex surfaces than on concave ones, the protrusion force magnitude in the direction of migration is larger on concave surfaces than on convex ones. These results offer a novel biomechanical explanation to substrate curvature regulation of cell migration: geometric constrains bias the direction of the protrusion force and facilitates persistent migration on concave surfaces.

  2. Les questions de migrations internationales (Questions of International Migrations).

    Science.gov (United States)

    Samman, Mouna Liliane

    1993-01-01

    Education about international migration should (1) utilize a framework of historical evolution; (2) stress the growing interdependence of nations; (3) emphasize universal moral values and the role of the individual in human rights; and (4) consider the complementary or competing portraits of international migration presented by the media. (DMM)

  3. Countering inbreeding with migration 1. Migration from unrelated ...

    African Journals Online (AJOL)

    The eff'ect of migration on inbreeding is moclelled fbr small populations with immigrants from a large unrelated population. Different migration rates and numbers fbr the two sexes are assumed, and a general recursion equation for inbreeding progress derived, which can be shown to lead to an equilibrium inbreeding ...

  4. Patterns of East to West migration in the context of European migration systems possibilities and limits of migration control

    OpenAIRE

    Irina Molodikova

    2008-01-01

    This paper gives an overview of the main migration trends of the CIS (Commonwealth of Independent States) migration system in the context of the development of EU migration and migration control and seeks to explain the peculiarities of the CIS migration system’s development.

  5. Migration, klima og sundhed

    DEFF Research Database (Denmark)

    Tellier, Siri; Carballo, Manuel

    2009-01-01

    environmental refugees find themselves and the consequences this may have. Finally, it points to the urgent need to reform health systems in both developing and developed countries to adapt to rapidly changing disease patterns and to become more responsive to them. Udgivelsesdato: 2009-Oct-26...

  6. Migration. Foreign affairs.

    Science.gov (United States)

    Moore, Alison

    2007-10-18

    Many in the NHS are unwilling to discuss migrant matters, possibly for fear of being thought racist--or because they do not have accurate data. The allocation system to PCTs may be inadequate in areas where there is rapid population growth. Differences in language, health needs and lifestyle between ethnic groups are challenging the NHS.

  7. Migration - utopia or myopia?

    Directory of Open Access Journals (Sweden)

    Peter Osborne

    1998-03-01

    Full Text Available Peter Osborne spent a sabbatical in northern America and was surprised that so many scientists and students stated that caribou migration was largely the result of mosquito pressure. He failed however to find any documented evidence of this claim although he was constantly confronted by the well known «facts» that mosquitoes had been observed to drive caribou crazy and even kill juveniles. The issue Osborne wishes to focus is that an experimentally unsubstantiated anthropomorphism appears to have become critical evidence in support of a theory. A recent article in Nature (393, 511-513, 1998 devoted to the uses of 'science in fiction' to stimulate thought and discussion about aspects of academia encouraged him to write the following comment in the form of a parody of ancient Greek dialogues.

  8. Nightly Test system migration

    CERN Document Server

    Win-Lime, Kevin

    2013-01-01

    The summer student program allows students to participate to the Cern adventure. They can follow several interesting lectures about particle science and participate to the experiment work. As a summer student, I had worked for LHCb experiment. LHCb uses a lot of software to analyze its data. All this software is organized in packages and projects. They are built and tested during the night using an automated system and the results are displayed on a web interface. Actually, LHCb is changing this system. It is looking for a replacement candidate. So I was charged to unify some internal interfaces to permit a swift migration. In this document, I will describe shortly the system used by LHCb, then I will explain what I have done in detail.

  9. Migration issues important -- Mongolia.

    Science.gov (United States)

    1999-01-01

    Migration and urbanization are issues that require increasing attention in Mongolia. Mr. Sodov Sonin, Minister of Health and Social Welfare, stated at the Forum that fertility has declined, but mortality, in particular the mortality of children and mothers, is still too high. In addition, there is a significant gap between the knowledge of and behaviors concerning reproductive health, which is one of the causes of the country's high abortion rates. However, on the positive side, literacy is high among women--70% of the students in Mongolia's higher educational institutions are female and the State recognizes equal rights for women. Moreover, programs that promote health and education, including the National Program on Reproductive Health, are being implemented; but despite all these, Mongolia still lacks the human and financial resources to implement the ICPD Program of Action satisfactorily. The country also needs dramatic changes in mind-set and in terms of capacity building, given its ongoing socioeconomic transition.

  10. Migration: the trends converge.

    Science.gov (United States)

    1985-09-01

    Formerly, Australia, New Zealand, Canada, and the US have served as permanent destinations for immigrants, while Europe's migrants have moved to more northerly countries to work for a time and then returned home. From 1973-1975 Europe's recruitment of foreign workers virtually ended, although family reunion for those immigrants allowed in was encouraged. Problems resulting from this new settlement migration include low paying jobs for immigrant women, high unemployment, and inadequate education for immigrant children. Illegal migrants from Latin America and the Caribbean enter the US and Canada each year while illegal North African immigrants enter Italy, Spain, and Greece. North America, Australia, and Europe have all received political refugees from Asia and Latin America. Increasingly, these foreigners compete in the labor market rather than simply fill jobs the native workers do not want. All the receiving countries have similar policy priorities: 1) more effective ways for controlling and monitoring inflows and checking illegal immigration; 2) encouraging normal living patterns and accepting refugees; and 3) integrating permanent migrants into the host country. Europe's public immigration encouragement prior to the first oil shock, has left some countries with a labor force that is reluctant to return home. It is unlikely that Europe will welcome foreign labor again in this decade, since unemployment among young people and women is high and family reunion programs may still bring in many immigrants. Less immigration pattern change will probably occur in North America, Australia, and New Zealand since these countries' populations are still growing and wages are more flexible. Immigration, regulated by policy, and emigration, determined by market forces, now are working in the same direction and will likely reduce future migration flows.

  11. Resonant Transneptunian Binaries: Evidence for Slow Migration of Neptune

    Science.gov (United States)

    Noll, Keith S.; Grundy, W. M.; Schlichting, H. E.; Murray-Clay, R. A.; Benecchi, S. B.

    2012-01-01

    As Neptune migrated, its mean-motion resonances preceded it into the planetesimal disk. The efficiency of capture into mean motion resonances depends on the smoothness of Neptune's migration and the local population available to be captured. The two strongest resonances, the 3:2 at 39.4 AU and 2:1 at 47.7 AU, straddle the core repository of the physically distinct and binary-rich Cold Classicals, providing a unique opportunity to test the details of Neptune's migration. Smooth migration should result in a measurable difference between the 3:2 and 2:1 resonant object properties, with low inclination 2:1s having a high fraction of red binaries, mirroring that of the Cold Classicals while the 3:2 will would have fewer binaries. Rapid migration would generate a more homogeneous result. Resonant objects observed with HST show a higher rate of binaries in the 2:1 relative to the 3:2, significant at the 2cr level. This suggests slow Neptune migration over a large enough distance that the 2:1 swept through the Cold Classical region. Colors are available for only a fraction of these targets but a prevalence of red objects in outer Resonances has been reported. We report here on ongoing observations with HST in cycle 19 targeting all unobserved Resonants with observations that will measure color and search for binary companions using the WFC3.

  12. Constraints on Upward Migration of Hydraulic Fracturing Fluid and Brine

    Science.gov (United States)

    Flewelling, Samuel A; Sharma, Manu

    2014-01-01

    Recent increases in the use of hydraulic fracturing (HF) to aid extraction of oil and gas from black shales have raised concerns regarding potential environmental effects associated with predictions of upward migration of HF fluid and brine. Some recent studies have suggested that such upward migration can be large and that timescales for migration can be as short as a few years. In this article, we discuss the physical constraints on upward fluid migration from black shales (e.g., the Marcellus, Bakken, and Eagle Ford) to shallow aquifers, taking into account the potential changes to the subsurface brought about by HF. Our review of the literature indicates that HF affects a very limited portion of the entire thickness of the overlying bedrock and therefore, is unable to create direct hydraulic communication between black shales and shallow aquifers via induced fractures. As a result, upward migration of HF fluid and brine is controlled by preexisting hydraulic gradients and bedrock permeability. We show that in cases where there is an upward gradient, permeability is low, upward flow rates are low, and mean travel times are long (often >106 years). Consequently, the recently proposed rapid upward migration of brine and HF fluid, predicted to occur as a result of increased HF activity, does not appear to be physically plausible. Unrealistically high estimates of upward flow are the result of invalid assumptions about HF and the hydrogeology of sedimentary basins. PMID:23895673

  13. Rural-urban migration and urban employment opportunities in Nigeria.

    Science.gov (United States)

    Okpara, E E

    1986-01-01

    The author suggests that most studies of rural-urban migration in the third world today are based on the European experience during the Industrial Revolution. He contends that the assumption that most migrants find wage employment in a rapidly growing modern industrial sector is not valid, particularly in Western Africa, where the pace of industrialization lags behind the rate of urbanization. Data from Nigeria are used to show that many potential migrants are aware of this situation and migrate seeking self-employment in informal sector trading activities.

  14. Family migration and migrant integration

    NARCIS (Netherlands)

    Bonjour, S.; Kraler, A.; Triandafyllidou, A.

    2016-01-01

    Family migration and integration are intimately related concepts in contemporary policy discourses in major migrant receiving countries. In these discourses, both family related migration as such and the migrant family as an institution are problematised with regard to their relation to integration.

  15. Migration Decisions of Skilled Migrants

    National Research Council Canada - National Science Library

    Eskelä, Elina

    2013-01-01

    ...-speaking destination countries such as the United States. This paper enhances the understanding of student mobility in exploring the migration motives of international students in the case of a less common destination. Keywords International students skilled migration immigration Helsinki Finland Elina Eskel* University of Helsinki, Finland Received 24 Oc...

  16. Challenged by migration: Europe's options

    NARCIS (Netherlands)

    Constant, Amelie F.; Zimmermann, Klaus F.

    2017-01-01

    This paper examines the migration and labour mobility in the European Union and elaborates on their importance for the existence of the EU. Against all measures of success, the current public debate seems to suggest that the political consensus that migration is beneficial is broken. This comes with

  17. 178 GLOBALIZATION, MIGRATION AND UNDERDEVELOPMENT ...

    African Journals Online (AJOL)

    179 imbues them with less international profile. More recently, the refuges problem could in some sense be seen as a form of forced migration, but these are also largely within the continent. The Migration that engages our attention in this paper specifically relates to the voluntary movement of people from one continent to ...

  18. Africa: Setting for Human Migration

    Science.gov (United States)

    Buuba, Babacar Diop

    2007-01-01

    Analysis of African migrations can help to understand prehistoric, historical, ancient modern and contemporaneous migrations. Movements of populations were and continue to be so intense that, for some analysts, they constitute one of the dominant trends of the history and destiny of the very old continent. African and non-African states, whether…

  19. International migration and its regulation

    NARCIS (Netherlands)

    Baganha, M.I.; Doomernik, J.M.J.; Gsir, S.; Hofmann, M.; Kraler, A.; Penninx, R; Kraal, K.; Berger, M.

    2006-01-01

    A fundamental issue in society today, migration has been undergoing a new dynamic transformation, calling for new policy approaches. This new dynamic is not yet understood clearly, let alone that adequate policy answers for ‘the managing’ of these new migration processes and the consequences for

  20. Measuring International Migration in Azerbaijan

    Directory of Open Access Journals (Sweden)

    Serhat Yüksel

    2018-01-01

    Full Text Available International migration significantly affects economic, social, cultural, and political factors of the country. Owing to this situation, it can be said that the reasons of international migration should be analyzed in order to control this problem. The purpose of this study is to determine the influencing factors of international migration in Azerbaijan. In this scope, annual data of 11 explanatory variables for the period of 1995–2015 was analyzed via Multivariate Adaptive Regression Splines (MARS method. According to the results of this analysis, it was identified that people prefer to move other countries in case of high unemployment rates. In addition, the results of the study show that population growth and high mortality rate increases the migration level. While considering these results, it was recommended that Azerbaijan should focus on these aspects to control international migration problem.

  1. Current Migration Movements in Europe

    Directory of Open Access Journals (Sweden)

    Jelena Zlatković Winter

    2004-09-01

    Full Text Available After a brief historical review of migrations in Europe, the paper focuses on current migration trends and their consequences. At the end of the 1950s, Western Europe began to recruit labour from several Mediterranean countries – Italy, Spain, Portugal and former Yugoslavia, and later from Morocco, Algeria, Tunisia and Turkey. Some countries, such as France, Great Britain and the Netherlands, recruited also workers from their former colonies. In 1970 Germany had the highest absolute number of foreigners, followed by France, and then Switzerland and Belgium. The total number of immigrants in Western Europe was twelve million. During the 1970s mass recruitment of foreign workers was abandoned, and only the arrival of their family members was permitted, which led to family reunification in the countries of employment. Europe closed its borders, with the result that clandestine migration increased. The year 1989 was a turning point in the history of international migrations. The political changes in Central and Eastern Europe brought about mass migration to the West, which culminated in the so-called “mass movement of 1989–1990”. The arrival of ethnic Germans in Germany, migration inside and outside of the territory of the former Soviet Union, an increase in the number of asylum seekers and displaced persons, due to armed conflicts, are – according to the author – the main traits of current migration. The main part of the paper discusses the causes and effects of this mass wave, as well as trends in labour migration, which is still present. The second part of the paper, after presenting a typology of migrations, deals with the complex processes that brought about the formation of new communities and led to the phenomenon of new ethnic minorities and to corresponding migration policies in Western European countries that had to address these issues.

  2. Measuring the Environmental Dimensions of Human Migration: The Demographer’s Toolkit

    Science.gov (United States)

    Hunter, Lori M.; Gray, Clark L.

    2014-01-01

    In recent years, the empirical literature linking environmental factors and human migration has grown rapidly and gained increasing visibility among scholars and the policy community. Still, this body of research uses a wide range of methodological approaches for assessing environment-migration relationships. Without comparable data and measures across a range of contexts, it is impossible to make generalizations that would facilitate the development of future migration scenarios. Demographic researchers have a large methodological toolkit for measuring migration as well as modeling its drivers. This toolkit includes population censuses, household surveys, survival analysis and multi-level modeling. This paper’s purpose is to introduce climate change researchers to demographic data and methods and to review exemplary studies of the environmental dimensions of human migration. Our intention is to foster interdisciplinary understanding and scholarship, and to promote high quality research on environment and migration that will lead toward broader knowledge of this association. PMID:25177108

  3. The challenge of migration and health.

    Science.gov (United States)

    Carballo, Manuel

    2006-01-01

    Dr Manuel Carballo of the International Centre for Migration and Health provides the background to migration and its impact on the health of migrating peoples and the health care systems that treat them.

  4. Microfluidics to define leukocyte migration patterns

    NARCIS (Netherlands)

    Boneschansker, Johan

    2017-01-01

    Leukocyte migration into tissues is characteristic of inflammation. In this thesis, we design and validate microfluidic devices that allow for precise quantification of leukocyte migration patterns. Our microfluidic platform can quantify migration patterns using single-cell quantitative metrics that

  5. Migration process control in the modern society

    OpenAIRE

    A R Dimaev

    2009-01-01

    The sociological way of the migration phenomenon can be considered only in complex. As a social science of migration we should understand the social science control, which is based on direct and indirect control of migration process.

  6. Internal and international migration in Nepal.

    Science.gov (United States)

    Kc, B K

    1987-01-01

    Internal and international migration trends in Nepal are reviewed using data from the 1971 and 1981 censuses. The causes and consequences of migration are considered. The need for policies to control migration of all kinds is stressed.

  7. Four decades of Andean timberline migration and implications for biodiversity loss with climate change.

    Directory of Open Access Journals (Sweden)

    David A Lutz

    Full Text Available Rapid 21st-century climate change may lead to large population decreases and extinction in tropical montane cloud forest species in the Andes. While prior research has focused on species migrations per se, ecotones may respond to different environmental factors than species. Even if species can migrate in response to climate change, if ecotones do not they can function as hard barriers to species migrations, making ecotone migrations central to understanding species persistence under scenarios of climate change. We examined a 42-year span of aerial photographs and high resolution satellite imagery to calculate migration rates of timberline--the grassland-forest ecotone-inside and outside of protected areas in the high Peruvian Andes. We found that timberline in protected areas was more likely to migrate upward in elevation than in areas with frequent cattle grazing and fire. However, rates in both protected (0.24 m yr(-1 and unprotected (0.05 m yr(-1 areas are only 0.5-2.3% of the rates needed to stay in equilibrium with projected climate by 2100. These ecotone migration rates are 12.5 to 110 times slower than the observed species migration rates within the same forest, suggesting a barrier to migration for mid- and high-elevation species. We anticipate that the ecotone will be a hard barrier to migration under future climate change, leading to drastic population and biodiversity losses in the region unless intensive management steps are taken.

  8. MIGRATION IMPACT ON ECONOMICAL SITUATION

    Directory of Open Access Journals (Sweden)

    Virginia COJOCARU

    2016-01-01

    Full Text Available This paper presents recent trends and flows of labor migration and its impact on economic and social life. Main aim of this research sets up the influence of the migration on the European economics and its competitiveness. Methods of research are: method of comparison, analysis method, method of deduction, method of statistics, modeling method. The economic impact of migration has been intensively studied but is still often driven by ill-informed perceptions, which, in turn, can lead to public antagonism towards migration. These negative views risk jeopardising efforts to adapt migration policies to the new economic and demographic challenges facing many countries. Migration Policy looks at the evidence for how immigrants affect the economy in three main areas: The labour market, public purse and economic growth. In Europe, the scope of labour mobility greatly increased within the EU/EFTA zones following the EU enlargements of 2004, 2007 and 2014-2015. This added to labour markets’ adjustment capacity. Recent estimates suggest that as much as a quarter of the asymmetric labour market shock – that is occurring at different times and with different intensities across countries – may have been absorbed by migration within a year.

  9. On the concept of migration policy

    OpenAIRE

    DZHANSARAYEVA RIMA YERENATOVNA; MALIKOVA SHOLPAN BALTABEKOVNA

    2015-01-01

    The article analyzes existing in the different sources of non-fiction variety of interpretations of the term “migration policy”. The variety of approaches to the concept of “politics” and “the migration process” gives rise to different points of view on the vision of migration policy. Contradictions are clearly seen in the difference in definitions of migration policy. Migration policy a purposeful activity of political institutions, aimed at streamlining and regulation of migration processes...

  10. Migration in two directions.

    Science.gov (United States)

    Slim, Rita; Koussa, Salam; Awada, Hassan; Yaghi, Cesar; Honein, Khalil; Sayegh, Raymond

    2009-01-01

    Percutaneous endoscopic gastrostomy (PEG), the modality of choice for long-term enteral access, is generally a safe procedure but can be associated with many potential complications. Report two different and late complications of PEG in two patients fed at home, leading them to the emergency department. A 75-year-old man and a 14-year-old young man with PEG presented to the emergency department with two different complications related to the gastrostomy tube. The first patient developed fever and deterioration in mental status due to parietal abscess which developed secondary to the migration of the internal button of the gastrostomy tube in the abdominal wall. He was treated with antibiotics and the gastrostomy tube was extracted. The second one presented upper gastrointestinal bleeding due to intestinal perforation at the level of the internal button of the gastrostomy tube. Bleeding and perforation were treated conservatively and he had a good evolution. Persons taking care of patients with PEG tube must be aware of potential complications. The position and the permeability of the tube must be systematically checked before feeding and medical advice should immediately be asked for in case of doubt or in the presence of any alarming sign.

  11. Psychosocial Aspects of Migration

    Directory of Open Access Journals (Sweden)

    Ayla Tuzcu

    2014-02-01

    Full Text Available The incident of migration that occurs as a result of the mobility of individuals between various regions and is considered a social change process brings along various factors. Among these factors, the most important one is the culture of the new society where the immigrant begins to live and the process of adaptation with this culture. Individuals from different cultures are required to live together, cope with differences and overcome the difficulties. The process of adaptation to the new lifestyle might cause the individual to have some feelings such as loneliness, socially isolation, being alienated, being regretful and self-depreciation, and consequently experience a greater stress. Being unable to cope with stress efficiently creates risks in individuals in terms of health problems such as anxiety and depression. Healthcare professionals are required to evaluate life styles, difficulties and coping levels of immigrants in order to protect and develop their mental health. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2014; 6(1.000: 56-66

  12. Population commission discusses international migration.

    Science.gov (United States)

    1997-01-01

    At the 30th session of the Commission on Population and Development during February 24-28, 1997, international migration was the main topic, with special linkages between migration and development and on gender issues and the family. New and emerging issues were also considered. Members stressed the need for more reliable data on migration, the direction of migrants flows, and the characteristics of migrants. The Commission requested a task force on basic social services to hold a technical symposium of experts on international migration in 1998. Its chair, Dr. Nafis Sadik, said that migration issues should based on the reality of choice not on coercive measures or quotas. Almost half of the migrants globally are women. The Commission was given a new impetus by the International Conference on Population and Development held at Cairo in 1994. Migration pressures intensified in the second half of the 1980s and in the early 1990s, creating areas of concern: the negative impact of short-term migration on working conditions in host countries; migration pressures emanating from climatic change; the protection of migrant women and their children; the right of receiving countries to regulate access to their territory; the adverse consequences of forced migration; the situation of persons whose asylum claims have been rejected; the trafficking in women and children, prostitution and coercive adoption; and the sudden and massive arrival of refugees in need of international protection. The 1998 session of the Commission will feature the theme of health and mortality, with special emphasis on the linkages between health and development and on gender and age.

  13. Migration and the Wage Curve:

    DEFF Research Database (Denmark)

    Brücker, Herbert; Jahn, Elke J.

      Based on a wage curve approach we examine the labor market effects of migration in Germany. The wage curve relies on the assumption that wages respond to a change in the unemployment rate, albeit imperfectly. This allows one to derive the wage and employment effects of migration simultaneously...... with a vocational degree. The wage and employment effects of migration are moderate: a 1 percent increase in the German labor force through immigration increases the aggregate unemployment rate by less than 0.1 percentage points and reduces average wages by less 0.1 percent. While native workers benefit from...

  14. Rural migration and health care

    DEFF Research Database (Denmark)

    Svendsen, Gunnar Lind Haase; Jensen, Marit Vatn

    This literature study focuses on possible links between access to health services and migration in rural areas. Why do people move to or from rural areas or why do they stay? What determines where people settle? And, in this context, do local health care services play an important or minor role......, or no role at all? First, the paper reports on key findings from rural migration studies, in order to shed light on two migration trends: urbanization and counter-urbanization. Then we take a closer look on settlement preferences in rural areas, including the impact of health care facilities. Finally, we end...

  15. Countering inbreeding with migration 1. Migration from unrelated ...

    African Journals Online (AJOL)

    l2-(1 -rn)(t -m)l|,. (1.14) with all terms as defined fbr (1.5). Equation (1.14) does not appear to be directly amenable to the development of general rules for the limitation ... effects of migration and restricted population size with equal numbers of the two sexes and with only male migration. N'lale rnigrant number. Herd size l1 .'l.

  16. Effects of global gas flows on type I migration

    Science.gov (United States)

    Ogihara, Masahiro; Kokubo, Eiichiro; Suzuki, Takeru K.; Morbidelli, Alessandro; Crida, Aurélien

    2017-12-01

    Context. Magnetically-driven disk winds would alter the surface density slope of gas in the inner region of a protoplanetary disk (r ≲ 1 au). This in turn affects planet formation. Recently, the effect of disk wind torque has been considered with the suggestion that it would carve out the surface density of the disk from inside and would induce global gas flows (wind-driven accretion). Aims: We aim to investigate effects of global gas flows on type I migration and also examine planet formation. Methods: A simplified approach was taken to address this issue, and N-body simulations with isolation-mass planets were also performed. Results: In previous studies, the effect of gas flow induced by turbulence-driven accretion has been taken into account for its desaturation effect of the corotation torque. If more rapid gas flows (e.g., wind-driven accretion) are considered, the desaturation effect can be modified. In MRI-inactive disks, in which the wind-driven accretion dominates the disk evolution, the gas flow at the midplane plays an important role. If this flow is fast, the corotation torque is efficiently desaturated. Then, the fact that the surface density slope can be positive in the inner region due to the wind torque can generate an outward migration region extended to super-Earth mass planets. In this case, we observe that no planets fall onto the central star in N-body simulations with migration forces imposed to reproduce such migration pattern. We also see that super-Earth mass planets can undergo outward migration. Conclusions: Relatively rapid gas flows affects type I migration and thus the formation of close-in planets.

  17. NASTRAN migration to UNIX

    Science.gov (United States)

    Chan, Gordon C.; Turner, Horace Q.

    1990-01-01

    COSMIC/NASTRAN, as it is supported and maintained by COSMIC, runs on four main-frame computers - CDC, VAX, IBM and UNIVAC. COSMIC/NASTRAN on other computers, such as CRAY, AMDAHL, PRIME, CONVEX, etc., is available commercially from a number of third party organizations. All these computers, with their own one-of-a-kind operating systems, make NASTRAN machine dependent. The job control language (JCL), the file management, and the program execution procedure of these computers are vastly different, although 95 percent of NASTRAN source code was written in standard ANSI FORTRAN 77. The advantage of the UNIX operating system is that it has no machine boundary. UNIX is becoming widely used in many workstations, mini's, super-PC's, and even some main-frame computers. NASTRAN for the UNIX operating system is definitely the way to go in the future, and makes NASTRAN available to a host of computers, big and small. Since 1985, many NASTRAN improvements and enhancements were made to conform to the ANSI FORTRAN 77 standards. A major UNIX migration effort was incorporated into COSMIC NASTRAN 1990 release. As a pioneer work for the UNIX environment, a version of COSMIC 89 NASTRAN was officially released in October 1989 for DEC ULTRIX VAXstation 3100 (with VMS extensions). A COSMIC 90 NASTRAN version for DEC ULTRIX DECstation 3100 (with RISC) is planned for April 1990 release. Both workstations are UNIX based computers. The COSMIC 90 NASTRAN will be made available on a TK50 tape for the DEC ULTRIX workstations. Previously in 1988, an 88 NASTRAN version was tested successfully on a SiliconGraphics workstation.

  18. [International migration: 1979].

    Science.gov (United States)

    1981-01-01

    Statistics on international migration in Panama in 1979 are provided for the 3 airports, 6 seaports, and 2 border crossings used by international travelers. The categories of visitors, temporary visitors, immigrants, and residents among those entering and leaving the country are defined and the data collection procedures are briefly specified. Between 1975-79, the number of persons entering the country through all points increased from 392,449 to 520,454, while the number departing increased from 397,759 to a figure provisionally estimated at 514,250. In 1979, 317,303 men and 203,151 women entered the country, 427,527 by air, 89,764 by land, and 3,163 by sea. 473 men and 355 women immigrated, all arriving by air. 391,502 of those entering were visitors, 2,407 were temporary visitors, and 98,589 were residents, of whom 81,462 were Panamanian and 17,127 foreign. Another table indicates the number of persons by category entering at each point by month; December had the highest number of arrivals, 56,070, followed by July, with 47,889. Other tables indicate the number of arrivals by category according to country of nationality and country of permanent residence; the number of arrivals by sex and category in 5-year age groups; the number of visitors entering for motives related to travel according to nationality and country of residence; the number entering by duration of stay, according to reasons for travel and country of residence; the number entering through the airport at Tocumen or the border crossing at Paso de Canoa, by motives for travel, according to country of residence, and by sex and age; and the number of returning Panamanian residents by port of entry and nationality, according to point of origin. Data are also provided on the number leaving by category for each point of departure and month of departure.

  19. The migration challenge for PAYG

    Czech Academy of Sciences Publication Activity Database

    Aslanyan, Gurgen

    2014-01-01

    Roč. 27, č. 4 (2014), s. 1023-1038 ISSN 0933-1433 Institutional support: PRVOUK-P23 Keywords : public pension s * PAYG * unskilled migration Subject RIV: AH - Economics Impact factor: 1.109, year: 2014

  20. The migration challenge for PAYG

    Czech Academy of Sciences Publication Activity Database

    Aslanyan, Gurgen

    2014-01-01

    Roč. 27, č. 4 (2014), s. 1023-1038 ISSN 0933-1433 Institutional support: RVO:67985998 Keywords : public pension s * PAYG * unskilled migration Subject RIV: AH - Economics Impact factor: 1.109, year: 2014

  1. Migration, distress and cultural identity

    National Research Council Canada - National Science Library

    Bhugra, Dinesh

    2004-01-01

    ...; they also attempt to settle down by either assimilation or biculturalism. In this paper, various hypotheses explaining the act of migration and its relationship with mental distress are described...

  2. Grounding a theory of African migration in recent data on Ghana.

    Science.gov (United States)

    Achanfuo-yeboah, D

    1993-06-01

    This article discusses the development of a single theory of migration in Africa, which accounts for social, economic, cultural, psychological, and demographic factors. Prior migration literature refers to many countries in Africa. The empirical test in this paper is based on Ghana and data for 1960, 1970, and 1984. Ghana is described as having rapid population growth and urbanization reaching 12.5 million in 1984. The economy is based on agriculture, mining, and manufacturing. Education is available for free through the secondary school level (since 1965). The general theory of migration holds that the nature, intensity, direction, and patterns of migration are shaped by social, cultural, economic, and political developments. Sociocultural developments, or nonagricultural occupations and educational resources, may influence the flow of migration to urban areas. The regression model shows that 70% of the variance in net migration is explained by education, economic activity, and population growth. Education determines the direction and intensity of migration. A unit value of education causes a change of 0.251952 in the value of net migration. Norms, values, and beliefs are affected by educational and employment opportunities and are influenced by factors such as kinship, clan, language, beliefs, and religion. Economic infrastructure, industrialization, employment opportunities, and increased wages and salaries exert a pull on migrants. During the 1960s, Ghana attracted migrants from Nigeria. During the 1970s and 1980s, the reverse occurred. Migrants tend to move based on expectations of higher wages and better employment. In a bivariate relationship, economic activity explains 62% of the variance in migration. A unit change in the value of economic activity leads to a change of 1.379382 in the value of net migration. The literature emphasizes rural-urban flows, but migration in Gwan state in Cameroon and Udo state in Nigeria reflects the prevalence of rural

  3. Migration of the Nellix endoprosthesis.

    Science.gov (United States)

    England, Andrew; Torella, Francesco; Fisher, Robert K; McWilliams, Richard G

    2016-08-01

    This study reports the incidence and sequelae of migration of the Nellix (Endologix Inc, Irvine, Calif) endoprosthesis after endovascular aneurysm sealing. A review was performed of the follow-up imaging of all endovascular aneurysm sealing patients in a university hospital endovascular program who had a minimum follow-up of 1 year. The first postoperative and latest follow-up computed tomography scans were used to measure the distances between the proximal and distal borders of the stent grafts relative to reference vessels using a previously validated technique. Device migration was based on previously established criteria and defined as any stent graft movement of ≥4 mm related to a predefined reference vessel. Device movement in a caudal direction was given a positive value, and movement in a cranial direction was denoted by a negative value. Eighteen patients (35 stent grafts) were eligible for inclusion in this retrospective review. The mean preoperative abdominal aortic aneurysm diameter was 57 mm (standard deviation [SD], 5; range, 50-67 mm) and aortic neck length was 30 mm (SD, 16; range, 6-62 mm). Proximal migration, according to study definitions, was identified in six stent grafts (17%), all in a caudal direction. At 1 year the mean proximal migration distance was +6.6 mm (SD, 1.6; range, +4.7-+9.2 mm). Migration occurred in a single stent graft in four patients and bilaterally in one. No distal migration occurred. Proximal migration of the Nellix endoprosthesis does occur and was without any sequelae in our series. Further investigations into the long-term positional stability of the Nellix device, together with a more thorough understanding of the etiology and consequences of migration, are required. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  4. Metallicity, planetary formation and migration

    OpenAIRE

    Livio, M.; Pringle, J. E.

    2003-01-01

    Recent observations show a clear correlation between the probability of hosting a planet and the metallicity of the parent star. Since radial velocity surveys are biased, however, towards detecting planets with short orbital periods, the probability-metallicity correlation could merely reflect a dependence of migration rates on metallicity. We investigated the possibility, but find no basis to suggest that the migration process is sensitive to the metallicity. The indication is, therefore, th...

  5. Computational Economic Modeling of Migration

    OpenAIRE

    Klabunde, Anna

    2014-01-01

    In this paper an agent-based model of endogenously evolving migrant networks is developed to identify the determinants of migration and return decisions. Individuals are connected by links, the strength of which declines over time and distance. Methodologically, this paper combines parameterization using data from the Mexican Migration Project with calibration. It is shown that expected earnings, an idiosyncratic home bias, network ties to other migrants, strength of links to the home country...

  6. European Integration and Labour Migration

    Directory of Open Access Journals (Sweden)

    Julda Kielyte

    2010-11-01

    Full Text Available The present paper studies how European integration might affect the migration of workers in the enlarged EU. Unlike the reduced-form migration models, we base our empirical analysis on the theory of economic geography à la Krugman (1991, which provides an alternative modelling of migration pull and push factors. Parameters of the theoretical model are estimated econometrically using historical migration data. Our empirical findings suggest that European integration would trigger selective migration between the countries in the enlarged EU. In the Baltics, Lithuania would gain about 7.25% of the total work force. In the Visegrád Four, the share of the mobile labour force would increase the most in Hungary, 8.35%, compared to the pre-integration state. Our predictions for the East-West migration are moderate and lower than those of reduced-form models: between 5.44% (from the Baltics and 3.61% (from the Visegrád Four would emigrate to the EU North. Because migrants not only follow market potential, but also shape the region’s market potential, the long-run agglomeration forces are sufficiently weak to make a swift emergence of a core-periphery pattern in the enlarged EU very unlikely.

  7. The dynamics of mass migration

    Science.gov (United States)

    Massey, Douglas S.; Zenteno, Rene M.

    1999-01-01

    We specify a set of equations defining a dynamic model of international migration and estimate its parameters by using data specially collected in Mexico. We then used it to project the a hypothetical Mexican community population forward in time. Beginning with a stable population of 10,000 people, we project ahead 50 years under three different assumptions: no international migration; constant probabilities of in- and out-migration, and dynamic schedules of out- and in-migration that change as migratory experience accumulates. This exercise represents an attempt to model the self-feeding character of international migration noted by prior observers and theorists. Our model quantifies the mechanisms of cumulative causation predicted by social capital theory and illustrates the shortcomings of standard projection methodologies. The failure to model dynamically changing migration schedules yields a 5% overstatement of the projected size of the Mexican population after 50 years, an 11% understatement of the total number of U.S. migrants, a 15% understatement of the prevalence of U.S. migratory experience in the Mexican population, and an 85% understatement of the size of the Mexican population living in the United States. PMID:10220465

  8. MIGRATION OF SMALL MOONS IN SATURN's RINGS

    Energy Technology Data Exchange (ETDEWEB)

    Bromley, Benjamin C. [Department of Physics and Astronomy, University of Utah, 115 S 1400 E, Rm 201, Salt Lake City, UT 84112 (United States); Kenyon, Scott J., E-mail: bromley@physics.utah.edu, E-mail: skenyon@cfa.harvard.edu [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)

    2013-02-20

    The motions of small moons through Saturn's rings provide excellent tests of radial migration models. In theory, torque exchange between these moons and ring particles leads to radial drift. We predict that moons with Hill radii r {sub H} {approx} 2-24 km should migrate through the A ring in 1000 yr. In this size range, moons orbiting in an empty gap or in a full ring eventually migrate at the same rate. Smaller moons or moonlets-such as the propellers-are trapped by diffusion of disk material into corotating orbits, creating inertial drag. Larger moons-such as Pan or Atlas-do not migrate because of their own inertia. Fast migration of 2-24 km moons should eliminate intermediate-size bodies from the A ring and may be responsible for the observed large-radius cutoff of r {sub H} {approx} 1-2 km in the size distribution of the A ring's propeller moonlets. Although the presence of Daphnis (r {sub H} Almost-Equal-To 5 km) inside the Keeler gap challenges this scenario, numerical simulations demonstrate that orbital resonances and stirring by distant, larger moons (e.g., Mimas) may be important factors. For Daphnis, stirring by distant moons seems the most promising mechanism to halt fast migration. Alternatively, Daphnis may be a recent addition to the ring that is settling into a low inclination orbit in {approx}10{sup 3} yr prior to a phase of rapid migration. We provide predictions of observational constraints required to discriminate among possible scenarios for Daphnis.

  9. Bromelain treatment decreases neutrophil migration to sites of inflammation.

    Science.gov (United States)

    Fitzhugh, David J; Shan, Siqing; Dewhirst, Mark W; Hale, Laura P

    2008-07-01

    Bromelain, a mixture of proteases derived from pineapple stem, has been reported to have therapeutic benefits in a variety of inflammatory diseases, including murine inflammatory bowel disease. The purpose of this work was to understand potential mechanisms for this anti-inflammatory activity. Exposure to bromelain in vitro has been shown to remove a number of cell surface molecules that are vital to leukocyte trafficking, including CD128a/CXCR1 and CD128b/CXCR2 that serve as receptors for the neutrophil chemoattractant IL-8 and its murine homologues. We hypothesized that specific proteolytic removal of CD128 molecules by bromelain would inhibit neutrophil migration to IL-8 and thus decrease acute responses to inflammatory stimuli. Using an in vitro chemotaxis assay, we demonstrated a 40% reduction in migration of bromelain- vs. sham-treated human neutrophils in response to rhIL-8. Migration to the bacterial peptide analog fMLP was unaffected, indicating that bromelain does not induce a global defect in leukocyte migration. In vivo bromelain treatment generated a 50-85% reduction in neutrophil migration in 3 different murine models of leukocyte migration into the inflamed peritoneal cavity. Intravital microscopy demonstrated that although in vivo bromelain treatment transiently decreased leukocyte rolling, its primary long-term effect was abrogation of firm adhesion of leukocytes to blood vessels at the site of inflammation. These changes in adhesion were correlated with rapid re-expression of the bromelain-sensitive CD62L/L-selectin molecules that mediate rolling following in vivo bromelain treatment and minimal re-expression of CD128 over the time period studied. Taken together, these studies demonstrate that bromelain can effectively decrease neutrophil migration to sites of acute inflammation and support the specific removal of the CD128 chemokine receptor as a potential mechanism of action.

  10. Hawk migration over White Marsh, Maryland

    Science.gov (United States)

    Hackman, C.D.; Henny, C.J.

    1971-01-01

    The average number of hawks observed per hour in autumn migration between 1951-1954 and 1958-1961 at White Marsh, Maryland, was compared. The counts indicated that the status of the ten species observed may be divided into three categories: (1) relatively stable species (red-tailed hawk), (2) declining species (sparrow hawk, red-shouldered hawk, osprey, marsh hawk, and broad-winged hawk), and (3) rapidly declining species (peregrine falcon, Cooper?s hawk, bald eagle, and sharp-shinned hawk). The findings from this study are in agreement with the available literature and the status of the populations appears to be related to the food habits of the species.

  11. Migration transnationale des Vietnamiennes en Asie | CRDI - Centre ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Au cours des dix dernières années, on a observé une croissance rapide de la féminisation de la migration en Asie. Durant cette période, plus de 100 000 Vietnamiennes ont migré vers d'autres pays pour travailler, et un nombre équivalent pour se marier, dans le cadre d'arrangements commerciaux. Souvent, cependant ...

  12. Migration, pauvreté rurale et gestion communautaire des ressources ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    La migration, les déplacements et les réinstallations forcées sont loin d'être des phénomènes nouveaux au Cambodge. Après des années d'agitation et de troubles de l'ordre civil, et en raison de la croissance rapide de la population et du développement agricole, la plupart des terres irriguées et inondables au Cambodge ...

  13. Linking Poverty, Irregular Migration and Human Trafficking ...

    African Journals Online (AJOL)

    Migration literature suggests that poverty, irregular migration and human trafficking are causally linked. However, empirical studies linking these aspects of migration are scarce. This is because, as clandestine activities, data collection on these aspects of migration presents serious challenges. As a result of these ...

  14. Rural-Urban Migration in Colombia.

    Science.gov (United States)

    Schultz, T. Paul

    The rural-urban migration pattern in Colombia during the last 25 years has resulted in a population increase in urban areas from 30 to 52 percent of the total population. This study explores the causes of internal migration. Migration rates are estimated for various groups in the population to clarify who migrates and to where. A model of…

  15. Towards a new understanding of migration timing

    NARCIS (Netherlands)

    Kölzsch, Andrea; Muskens, Gerard; Kruckenberg, Helmut; Glazov, Peter; Weinzierl, Rolf; Nolet, Bart A.; Wikelski, Martin

    2016-01-01

    According to migration theory and several empirical studies, long-distance migrants are more time-limited during spring migration and should therefore migrate faster in spring than in autumn. Competition for the best breeding sites is supposed to be the main driver, but timing of migration is

  16. Distance and Intrastate College Student Migration

    Science.gov (United States)

    Alm, James; Winters, John V.

    2009-01-01

    Most studies of student migration focus on "interstate" migration of college students, largely because the aggregate data typically used are limited in geographic specificity to states. However, interstate migration is only a small part of the total student migration. Public institutions generally get most of their students from within…

  17. Avian migrants adjust migration in response to environmental conditions en route

    DEFF Research Database (Denmark)

    Tøttrup, Anders P; Thorup, Kasper; Rainio, Kalle

    2008-01-01

    The onset of migration in birds is assumed to be primarily under endogenous control in long-distance migrants. Recently, climate changes appear to have been driving a rapid change in breeding area arrival. However, little is known about the climatic factors affecting migratory birds during...... the migration cycle, or whether recently reported phenological changes are caused by plastic behavioural responses or evolutionary change. Here, we investigate how environmental conditions in the wintering areas as well as en route towards breeding areas affect timing of migration. Using data from 1984 to 2004...... covering the entire migration period every year from observatories located in the Middle East and northern Europe, we show that passage of the Sahara Desert is delayed and correlated with improved conditions in the wintering areas. By contrast, migrants travel more rapidly through Europe, and adjust...

  18. Migration transition in small Northern and Eastern Caribbean states.

    Science.gov (United States)

    Mcelroy, J L; De Albuquerque, K

    1988-01-01

    1 area of intra-Caribbean migration that has been overlooked is the "migration transition"--the transformation of rapidly modernizing societies from net labor exporters to net labor importers. This article assembles 8 case studies to 1) briefly present a spectrum of migration experiences in the Caribbean, 2) uncover some transitions under way, 3) pinpoint the forces that underlie the migration transition, and 4) point out some of the more important policy implications of labor migration reversals. The 8 island societies sampled for illustration purposes include 1) the Bahamas and the US Virgin Islands as post-migration transition societies (Zelinsky's advanced society), 2) the British Virgin Islands and the Cayman Islands as undergoing transition (Zelinsky's late transitional society), and 3) Anguilla, St. Kitts-Nevis, Turks and Caicos, and Montserrat as premigration transition societies (Zelinsky's early transitional society). Population data for the islands were derived primarily from the West Indian censuses and government statistics. These 8 historical sketches reveal certain commonalities. All are at various stages in a long-term economic restructuring to displace traditional staple crops with more income elastic, high value export services. In such societies, population growth and progress along the migration transition is an increasing function of this kind of successful export substitution. In addition, along the migration and economic transitions, such insular economies exhibit a relatively large public sector (20-30% of all activity), declining unemployment, increasing fiscal autonomy, and are committed to a development strategy remarkably similar to the "successful" model of the Bahamas and the US Virgin Islands. Cursory evidence suggests that, because of intersectoral competition for land and labor, there is an inverse relationship between farm effort/manufacturing employment and tourism intensity. This review suggests that small islands undergoing

  19. Migration and sustainability - compatible or contradictory?

    DEFF Research Database (Denmark)

    Røpke, Inge

    2006-01-01

    When the migration issue is discussed in a sustainability perspective, two questions are vital: 1) What is the relationship between migration and the global population growth? 2) What is the relationship between migration and consumption growth, and how does migration influence the distribution o...... of consumption possibilities both between and within industrialized and developing countries? Based on responses to these questions, it is argued that reasonably managed migration will be compatible with sustainable development....

  20. Seasonal survival probabilities suggest low migration mortality in migrating bats.

    Directory of Open Access Journals (Sweden)

    Simone Giavi

    Full Text Available Migration is adaptive if survival benefits are larger than costs of residency. Many aspects of bat migration ecology such as migratory costs, stopover site use and fidelity are largely unknown. Since many migrating bats are endangered, such information is urgently needed to promote conservation. We selected the migrating Leisler's bat (Nyctalus leisleri as model species and collected capture-recapture data in southern Switzerland year round during 6 years. We estimated seasonal survival and site fidelity with Cormack-Jolly-Seber models that accounted for the presence of transients fitted with Bayesian methods and assessed differences between sexes and seasons. Activity peaked in autumn and spring, whereas very few individuals were caught during summer. We hypothesize that the study site is a migratory stopover site used during fall and spring migration for most individuals, but there is also evidence for wintering. Additionally, we found strong clues for mating during fall. Summer survival that included two major migratory journeys was identical to winter survival in males and slightly higher in females, suggesting that the migratory journeys did not bear significant costs in terms of survival. Transience probability was in both seasons higher in males than in females. Our results suggest that, similarly to birds, Leisler's bat also use stopover sites during migration with high site fidelity. In contrast to most birds, the stopover site was also used for mating and migratory costs in terms of survival seemed to be low. Transients' analyses highlighted strong individual variation in site use which makes particularly challenging the study and modelling of their populations as well as their conservation.

  1. Seasonal survival probabilities suggest low migration mortality in migrating bats.

    Science.gov (United States)

    Giavi, Simone; Moretti, Marco; Bontadina, Fabio; Zambelli, Nicola; Schaub, Michael

    2014-01-01

    Migration is adaptive if survival benefits are larger than costs of residency. Many aspects of bat migration ecology such as migratory costs, stopover site use and fidelity are largely unknown. Since many migrating bats are endangered, such information is urgently needed to promote conservation. We selected the migrating Leisler's bat (Nyctalus leisleri) as model species and collected capture-recapture data in southern Switzerland year round during 6 years. We estimated seasonal survival and site fidelity with Cormack-Jolly-Seber models that accounted for the presence of transients fitted with Bayesian methods and assessed differences between sexes and seasons. Activity peaked in autumn and spring, whereas very few individuals were caught during summer. We hypothesize that the study site is a migratory stopover site used during fall and spring migration for most individuals, but there is also evidence for wintering. Additionally, we found strong clues for mating during fall. Summer survival that included two major migratory journeys was identical to winter survival in males and slightly higher in females, suggesting that the migratory journeys did not bear significant costs in terms of survival. Transience probability was in both seasons higher in males than in females. Our results suggest that, similarly to birds, Leisler's bat also use stopover sites during migration with high site fidelity. In contrast to most birds, the stopover site was also used for mating and migratory costs in terms of survival seemed to be low. Transients' analyses highlighted strong individual variation in site use which makes particularly challenging the study and modelling of their populations as well as their conservation.

  2. Environmental Change and Human Migration

    Directory of Open Access Journals (Sweden)

    Milan Mesić

    2014-12-01

    Full Text Available The 30th anniversary of the journal Migration and Ethnic Themes (MET is an occasion to announce a new key issue in the modern world’s future, which, in the authors’ opinion, is becoming the central theme within multidisciplinary and interdisciplinary field of migration studies. This concerns the displacement of people in the local and national context as well as migration across national borders, at the regional and global level, which are directly or indirectly caused by environmental change. The recent genetic studies on the origins and development of the human race further confirm that the human ecological migrations are the first and the oldest type of migrations at all. In addition, as archaeological and other findings suggest, just this type of migration sometimes played a key role in the emergence, decay and changing of ancient civilizations. It seems that the early researchers of migration studies had a lot in mind considering changes in natural environment as an important determinant of human spatial movements. The interest for this topic in the social sciences had trailed off until the re-emergence in the second half of the 1980s. The authors accept the classification on the causal categories of “environmental migration” as: a “natural” disasters; b “urban-industrial” disasters, and c exploitation and degradation of resources. Further, they deal with the definition of basic concepts, first of all with disputes about the definition of “environmental refugees” as opposed to “environmental migrants”. Finally, the authors systematize two major competing approaches to migration and migrants caused by environmental change. The first one is “the alarmist” and the second one “the sceptic” approach. Luckily, the Sceptics are able (for now to prove that deterrent worse-case scenarios on increasingly powerful and unstoppable “waves” of environmental migrants (refugees have not been achieved. This serves them as

  3. Migration transformation of two-dimensional magnetic vector and tensor fields

    DEFF Research Database (Denmark)

    Zhdanov, Michael; Cai, Hongzhu; Wilson, Glenn

    2012-01-01

    We introduce a new method of rapid interpretation of magnetic vector and tensor field data, based on ideas of potential field migration which extends the general principles of seismic and electromagnetic migration to potential fields. 2-D potential field migration represents a direct integral...... transformation of the observed magnetic fields into a subsurface susceptibility distribution, which can be used for interpretation or as an a priori model for subsequent regularized inversion. Potential field migration is very stable with respect to noise in the observed data because the transform is reduced...... to the downward continuation of a well-behaved analytical function. We present case studies for imaging of SQUID-based magnetic tensor data acquired over a magnetite skarn at Tallawang, Australia. The results obtained from magnetic tensor field migration agree very well with both Euler deconvolution and the known...

  4. The International-Migration Network

    CERN Document Server

    Fagiolo, Giorgio

    2012-01-01

    This paper studies international migration from a complex-network perspective. We define the international-migration network (IMN) as the weighted-directed graph where nodes are world countries and links account for the stock of migrants originated in a given country and living in another country at a given point in time. We characterize the binary and weighted architecture of the network and its evolution over time in the period 1960-2000. We find that the IMN is organized around a modular structure characterized by a small-world pattern displaying disassortativity and high clustering, with power-law distributed weighted-network statistics. We also show that a parsimonious gravity model of migration can account for most of observed IMN topological structure. Overall, our results suggest that socio-economic, geographical and political factors are more important than local-network properties in shaping the structure of the IMN.

  5. Cdc42-dependent leading edge coordination is essential for interstitial dendritic cell migration

    DEFF Research Database (Denmark)

    Lammermann, Tim; Renkawitz, Jorg; Wu, Xunwei

    2009-01-01

    Mature dendritic cells (DCs) moving from the skin to the lymph node are a prototypic example of rapidly migrating amoeboid leukocytes. Interstitial DC migration is directionally guided by chemokines, but independent of specific adhesive interactions with the tissue as well as pericellular...... the cells to move on two-dimensional surfaces, their in vivo motility is completely abrogated. We show that this difference is entirely caused by the geometrical complexity of the environment as multiple competing protrusions lead to instantaneous entanglement within three-dimensional extracellular matrix...... scaffolds. This demonstrates that the decisive factor for migrating DCs is not specific interaction with the extracellular environment, but adequate coordination of cytoskeletal flow....

  6. Influences of body size and environmental factors on autumn downstream migration of bull trout in the Boise River, Idaho

    Science.gov (United States)

    Monnot, L.; Dunham, J.B.; Hoem, T.; Koetsier, P.

    2008-01-01

    Many fishes migrate extensively through stream networks, yet patterns are commonly described only in terms of the origin and destination of migration (e.g., between natal and feeding habitats). To better understand patterns of migration in bull trout,Salvelinus confluentus we studied the influences of body size (total length [TL]) and environmental factors (stream temperature and discharge) on migrations in the Boise River basin, Idaho. During the autumns of 2001-2003, we tracked the downstream migrations of 174 radio-tagged bull trout ranging in size from 21 to 73 cm TL. The results indicated that large bull trout (>30 cm) were more likely than small fish to migrate rapidly downstream after spawning in headwater streams in early autumn. Large bull trout also had a higher probability of arriving at the current terminus of migration in the system, Arrowrock Reservoir. The rate of migration by small bull trout was more variable and individuals were less likely to move into Arrowrock Reservoir. The rate of downstream migration by all fish was slower when stream discharge was greater. Temperature was not associated with the rate of migration. These findings indicate that fish size and environmentally related changes in behavior have important influences on patterns of migration. In a broader context, these results and other recent work suggest, at least in some cases, that commonly used classifications of migratory behavior may not accurately reflect the full range of behaviors and variability among individuals (or life stages) and environmental conditions. ?? Copyright by the American Fisheries Society 2008.

  7. Climate Migration and Moral Responsibility.

    Science.gov (United States)

    Nawrotzki, Raphael

    Even though anthropogenic climate change is largely caused by industrialized nations, its burden is distributed unevenly with poor developing countries suffering the most. A common response to livelihood insecurities and destruction is migration. Using Peter Singer's "historical principle" this paper argues that a morally just evaluation requires taking causality between climate change and migration under consideration. The historical principle is employed to emphasize shortcomings in commonly made philosophical arguments to oppose immigration. The article concludes that none of these arguments is able to override the moral responsibility of industrialized countries to compensate for harms that their actions have caused.

  8. Women’s football migration

    DEFF Research Database (Denmark)

    Agergaard, Sine

    What is intriguing about women’s football as a cultural phenomenon is that unlike men’s football the finances and media interest for the game are sparse. Nevertheless we have found that migration of female football players is growing steadily and women’s football is becoming global in nature....... The question is then what drives this globalization process? According to our study of women’s football migration into Scandinavia, one of the centers of women’s football, transnational networks play a crucial role in mobilizing global migratory moves. Using the concept of friends-of-friends networks from Bale...

  9. Genre et migration au Maroc

    OpenAIRE

    KHACHANI, Mohamed

    2011-01-01

    Euro-Mediterranean Consortium for Applied Research on International Migration (CARIM) Une des principales caractéristiques récentes de la migration marocaine est sa tendance à une féminisation soutenue. Le projet migratoire - qui était un projet d’hommes - intéresse de plus en plus les femmes marocaines au point de constituer actuellement près de la moitié de l’effectif migratoire marocain. Cette reconnaissance de l'importance des femmes dans la construction de l'espace migratoire a placé ...

  10. Automation of Flexible Migration Workflows

    Directory of Open Access Journals (Sweden)

    Dirk von Suchodoletz

    2011-03-01

    Full Text Available Many digital preservation scenarios are based on the migration strategy, which itself is heavily tool-dependent. For popular, well-defined and often open file formats – e.g., digital images, such as PNG, GIF, JPEG – a wide range of tools exist. Migration workflows become more difficult with proprietary formats, as used by the several text processing applications becoming available in the last two decades. If a certain file format can not be rendered with actual software, emulation of the original environment remains a valid option. For instance, with the original Lotus AmiPro or Word Perfect, it is not a problem to save an object of this type in ASCII text or Rich Text Format. In specific environments, it is even possible to send the file to a virtual printer, thereby producing a PDF as a migration output. Such manual migration tasks typically involve human interaction, which may be feasible for a small number of objects, but not for larger batches of files.We propose a novel approach using a software-operated VNC abstraction layer in order to replace humans with machine interaction. Emulators or virtualization tools equipped with a VNC interface are very well suited for this approach. But screen, keyboard and mouse interaction is just part of the setup. Furthermore, digital objects need to be transferred into the original environment in order to be extracted after processing. Nevertheless, the complexity of the new generation of migration services is quickly rising; a preservation workflow is now comprised not only of the migration tool itself, but of a complete software and virtual hardware stack with recorded workflows linked to every supported migration scenario. Thus the requirements of OAIS management must include proper software archiving, emulator selection, system image and recording handling. The concept of view-paths could help either to automatically determine the proper pre-configured virtual environment or to set up system

  11. Networks, linkages, and migration systems.

    Science.gov (United States)

    Fawcett, J T

    1989-01-01

    Recent theoretical interest in migration systems calls attention to the functions of diverse linkages between countries in stimulating, directing,and maintaining international flows of people. This article proposes a conceptual framework for the non-people linkages in international migration systems and discusses the implications for population movement of the 4 categories and 3 types of linkages that define the network. The 4 categories include 1) state to state relations, 2) mass culture connections, 3) family and personal networks, and 4) migrant agency activities. The 3 types of linkages are 1) tangible linkages, 2) regulatory linkages, and 3) relational linkages.

  12. Rural migration in southern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Mosser, D.; Soden, D.L.

    1993-08-01

    This study reviews the history of migration in two rural counties in Southern Nevada. It is part of a larger study about the impact of a proposed high-level nuclear waste repository on in- and out-migration patterns in the state. The historical record suggests a boom and bust economic cycle has predominated in the region for the past century creating conditions that should be taken into account by decision makers when ascertaining the long-term impacts of the proposed repository.

  13. Full wavefield migration : Utilization of multiples in seismic migration

    NARCIS (Netherlands)

    Berkhout, A.J.; Verschuur, D.J.

    2012-01-01

    The next generation migration technology considers multiple scattering as vital information, allowing the industry to generate significantly better images of the subsurface. The proposed full wavefield algorithm (FWM) makes use of two-way wave theory that is formulated in terms of one-way

  14. Countering inbreeding with migration 2. Migration from related ...

    African Journals Online (AJOL)

    In conservation and breeding, large populations are important for evolutionary viability and selection progress. On the other hand, practical and economic rcasons may exist for population subdivision. These populations (islands) may be tied together to form effectively a single population (archipelago) by migration rates of ...

  15. Trade and migration: the case of NAFTA.

    Science.gov (United States)

    Martin, P L

    1993-01-01

    "This article provides background information on NAFTA [the North American Free Trade Agreement], reviews data on its economic effects, and summarizes studies and projections of NAFTA's likely effects on Mexico-to-U.S. migration. Migration factors (demand-pull, supply-push, and networks) are examined to determine whether NAFTA's effect on economic development particularly in the border areas will accelerate or retard migration. The conclusion is that NAFTA is likely to produce a temporary migration hump, slightly raising already high migration levels in the 1990s, but reducing the volume of Mexico-to-U.S. migration that would otherwise occur over subsequent decades." excerpt

  16. Plume capture by a migrating ridge: Analog geodynamic experiments

    Science.gov (United States)

    Mendez, J. S.; Hall, P.

    2010-12-01

    Paleomagnetic data from the Hawaii-Emperor Seamount Chain (HESC) suggests that the Hawaiian hotspot moved rapidly (~40 mm/yr) between 81 - 47 Ma but has remained relatively stationary since that time. This implies that the iconic bend in the HESC may in fact reflect the transition from a period of rapid hotspot motion to a stationary state, rather than a change in motion of the Pacific plate. Tarduno et al. (2009) have suggested that this period of rapid hotspot motion might be the surface expression of a plume conduit returning to a largely vertical orientation after having been “captured” and tilted by a migrating mid-ocean ridge. We report on a series of analog fluid dynamic experiments designed to characterize the interaction between a migrating spreading center and a thermally buoyant mantle plume. Experiments were conducted in a clear acrylic tank (100 cm x 70 cm x 50 cm) filled with commercial grade high-fructose corn syrup. Plate-driven flow is modeled by dragging two sheets of Mylar film (driven by independent DC motors) in opposite directions over the surface of the fluid. Ridge migration is achieved by moving the point at which the mylar sheets diverge using a separate motor drive. Buoyant plume flow is modeled using corn syrup introduced into the bottom of the tank from an external, heated, pressurized reservoir. Small (~2 mm diameter), neutrally buoyant Delrin spheres are mixed into reservoir of plume material to aid in visualization. Plate velocities and ridge migration rate are controlled and plume temperature monitored using LabView software. Experiments are recorded using digital video which is then analyzed using digital image analysis software to track the position and shape of the plume conduit throughout the course of the experiment. The intersection of the plume conduit with the surface of the fluid is taken as an analog for the locus of hotspot volcanism and tracked as a function of time to obtain a hotspot migration rate. Experiments are

  17. Globalisation and Migration in Africa

    African Journals Online (AJOL)

    forced and people who migrate on this reason without formal documents often risk harassment from immigration and law enforcement authorities of the host country. ..... crime. The ubiquity of cellular phones and proliferation of cyber communica- tion systems means that instant linkages can be made across countries without.

  18. [The questions of international migration].

    Science.gov (United States)

    Samman, M L

    1993-03-01

    International migrations have growing implications for both countries of destination. In the latter, the presence of foreigners and of members of their families today creates problems of integration, causes argument, and brings mounting xenophobia. Paralleling political, economic, and social measures taken by public authorities to respond to these difficulties, education needs to assist in diffusing the resulting social tensions by preparing the minds of learners and helping to develop new attitudes. In particular, when educational programs address questions of international migration, these should be treated in the framework of historical evolution in order that their real significance and their true temporal and spatial dimensions become apparent. It is also important that the growing interdependence between countries should be made plain, that national history should be placed in its international context, and that the true consequences of these developments should be made clear. In this context, learners need to be acquainted with Human Rights, thereby stressing universal moral values and the role of the individual. Lastly, questions relating to international migration are usually presented in the media in a selective and partial manner, and the young people who take in this information often accept the hasty judgments which are made of situations as proven facts. This is why all teaching about international migration needs to be considered or reconsidered in light of the complementary or competing actions of the media. (author's modified)

  19. Migration monitoring with automated technology

    Science.gov (United States)

    Rhonda L. Millikin

    2005-01-01

    Automated technology can supplement ground-based methods of migration monitoring by providing: (1) unbiased and automated sampling; (2) independent validation of current methods; (3) a larger sample area for landscape-level analysis of habitat selection for stopover, and (4) an opportunity to study flight behavior. In particular, radar-acoustic sensor fusion can...

  20. The concept of crisis migration

    Directory of Open Access Journals (Sweden)

    Jane McAdam

    2014-02-01

    Full Text Available "Crisis migration needs to be understood in terms of ‘tipping points’, which are triggered not just by events but also by underlying structural processes. It is important for policymakers for there to be an adequate theory behind the concept of ‘crisis migration’ so that responses are appropriate, timely and thoughtful. "

  1. Job Migration: A Collaborative Effort

    Science.gov (United States)

    Wagoner, Cynthia L.

    2012-01-01

    Music teachers often change jobs several times during their careers. Reasons for job changes vary, but regardless, these changes bring a different set of challenges. Sharing knowledge and learning are part and parcel of collaboration. So what if, as education professionals, music teachers decided to collaborate during job migrations? For all music…

  2. Marriage migration in the Netherlands

    NARCIS (Netherlands)

    Leen Sterckx; Jaco Dagevos; Willem Huijnk; Jantine van Lisdonk

    2014-01-01

    Original title: Huwelijksmigratie in Nederland When a man or woman living in the Netherlands embarks on a relationship with a partner from another country and the couple decide to build a married life together in the Netherlands, we call this marriage migration. The foreign partner who moves to

  3. Measuring attitudes towards unauthorized migration

    NARCIS (Netherlands)

    van der Veer, C.G.; Ommundsen, R.; Krumov, K.; Van Le, H.; Larsen, K.S.

    2008-01-01

    This study reports on the development and cross-national utility of a Likert type scale measuring attitudes toward unauthorized migration into a foreign country in two samples from "migrant-sending" nations. In the first phase a pool of 86 attitude statements were administered to a sample of 505

  4. Bird Migration Across the Himalayas

    NARCIS (Netherlands)

    Prins, Herbert H.T.; Namgail, Tsewang

    2017-01-01

    Birds migrating across the Himalayan region fly over the highest peaks in the world, facing immense physiological and climatic challenges. The authors show the different strategies used by birds to cope with these challenges. Many wetland avian species are seen in the high-altitude lakes of the

  5. Migrations of sandy beach meiofauna

    African Journals Online (AJOL)

    animals leaving the surface area when the wave surges crossed their habitat. His samples, however, only covered the ..... I ,,10 animals. •• 50 animals. FIGURE 4. Vertical distribution of meiofau na per 57 em1 in the top 24 em of sand during the l4-hour vertical migration experimenL. ~. N o o t"' o o -("). > > "f1. ~. -("). > :z: >. <.

  6. Post-translational modification-regulated leukocyte adhesion and migration.

    Science.gov (United States)

    Loh, Jia Tong; Su, I-Hsin

    2016-06-14

    Leukocytes undergo frequent phenotypic changes and rapidly infiltrate peripheral and lymphoid tissues in order to carry out immune responses. The recruitment of circulating leukocytes into inflamed tissues depends on integrin-mediated tethering and rolling of these cells on the vascular endothelium, followed by transmigration into the tissues. This dynamic process of migration requires the coordination of large numbers of cytosolic and transmembrane proteins whose functional activities are typically regulated by post-translational modifications (PTMs). Our recent studies have shown that the lysine methyltransferase, Ezh2, critically regulates integrin signalling and governs the adhesion dynamics of leukocytes via direct methylation of talin, a key molecule that controls these processes by linking integrins to the actin cytoskeleton. In this review, we will discuss the various modes of leukocyte migration and examine how PTMs of cytoskeletal/adhesion associated proteins play fundamental roles in the dynamic regulation of leukocyte migration. Furthermore, we will discuss molecular details of the adhesion dynamics controlled by Ezh2-mediated talin methylation and the potential implications of this novel regulatory mechanism for leukocyte migration, immune responses, and pathogenic processes, such as allergic contact dermatitis and tumorigenesis.

  7. Migration Theories and Mental Health in Toni Morrison's Jazz

    OpenAIRE

    Leila Tafreshi Motalgh; Wan Roselezam Wan Yahya

    2015-01-01

    This article aims to elaborate the relationship between migration and mental health problems that are evident in migrant women in Toni Morrison's Jazz (1992). To this end, pre-migration, migration and post-migration stress factors are identified in the novel based on Danish Bhugra's theory of migration. It seems that pre-migration stress factors and traumas are associated with the push theory of migration, while post-migration stresses are associated with the pull theory of migration. Despite...

  8. Mediterranean Migrations: Regionalisms Versus Globalisation

    Directory of Open Access Journals (Sweden)

    Martin Baldwin-Eduards

    2004-06-01

    Full Text Available This paper challenges the claim of globalisation as a cause ofimmigration into Southern Europe and, on an empirical basis, identifies regionalisation as being the primary issue, along with networked migratory patterns. However, the changing patterns of immigration do present challenges to both state and society. It is argued here that recent policy responses in Portugal, Italy and Spain have been inconsistent and irrational – reflecting more the ‘securitisation’ of migration than European reality. Earlier policy innovations are identified, by country and date: most of these have now been abandoned. It is suggested that all of Southern Europe has converged onto a statist, restrictionist model of immigration control that was formerly held only by Greece. The principal characteristics of this model are outlined, along with a migration flowchart and indicative data for migrant flows and sub-flows in Italy and Spain. In the final section, I try to show that the needs of the economy cannot be predicted, immigration cannot becontrolled in the manner currently being enforced across Southern Europe, and attempts to do so will damage rather than improve economic productivity and growth. The concept of an accomodating immigration policy is advanced, whereby the state tries to manage the needs of both employers and potential migrants. Six guidelines for policy development are suggested – most of which have alreadybeen successfully carried out in the European Union. These are the following: migration in order to find a job; circular cross-border migration; EU level negotiation of readmission agreements; the need for a variety of migration-for-employment schemes; legal residence should not depend upon continuity of employment; and discreet legalisation will still be needed in Southern Europe.

  9. Depth migration and de-migration for 3-D migration velocity analysis; Migration profondeur et demigration pour l'analyse de vitesse de migration 3D

    Energy Technology Data Exchange (ETDEWEB)

    Assouline, F.

    2001-07-01

    3-D seismic imaging of complex geologic structures requires the use of pre-stack imaging techniques, the post-stack ones being unsuitable in that case. Indeed, pre-stack depth migration is a technique which allows to image accurately complex structures provided that we have at our disposal a subsurface velocity model accurate enough. The determination of this velocity model is thus a key element for seismic imaging, and to this end, migration velocity analysis methods have met considerable interest. The SMART method is a specific migration velocity analysis method: the singularity of this method is that it does not rely on any restrictive assumptions on the complexity of the velocity model to determine. The SMART method uses a detour through the pre-stack depth migrated domain for extracting multi-offset kinematic information hardly accessible in the time domain. Once achieved the interpretation of the pre-stack depth migrated seismic data, a kinematic de-migration technique of the interpreted events enables to obtain a consistent kinematic database (i.e. reflection travel-times). Then, the inversion of these travel-times, by means of reflection tomography, allows the determination of an accurate velocity model. To be able to really image geologic structures for which the 3-D feature is predominant, we have studied the implementation of migration velocity analysis in 3-D in the context of the SMART method, and more generally, we have developed techniques allowing to overcome the intrinsic difficulties in the 3-D aspects of seismic imaging. Indeed, although formally the SMART method can be directly applied to the case of 3-D complex structures, the feasibility of its implementation requires to choose well the imaging domain. Once this choice done, it is also necessary to conceive a method allowing, via the associated de-migration, to obtain the reflection travel-times. We first consider the offset domain which constitutes, still today, the strategy most usually used

  10. Transvascular and interstitial migration of neutrophils in rat mesentery.

    Science.gov (United States)

    Ohashi, K L; Tung, D K; Wilson, J; Zweifach, B W; Schmid-Schönbein, G W

    1996-06-01

    The consequential implications of the leukocyte-endothelial cell adhesion reaction, as well as the subsequent migratory activity of the leukocytes within the interstitium proper, are currently known only in general phenomenological terms. Our objective was to carry out a detailed quantitative analysis of transendothelial and interstitial migration. We incorporated several new features, such as the video recording of time-lapse photography in conjunction with the time history of individual leukocytes under the influence of representative stimulators and inhibitors. The mesentery was suffused with the chemical activator N-formyl-met-leu-phe (fMLP, 5 x 10(-8) M) and histamine (10(-6) M) for periods up to 3 h. This leads to an attachment of neutrophils preferentially to the walls of small postcapillary venules followed by migration into the adjacent interstitium. The time interval between the initial neutrophil adhesion to the luminal side of the venules and their first appearance on the abluminal side of the venule wall was about 25 min. The time interval for the actual physical migration across the endothelium was only about 1-2 min. There was an initial increase in the number of neutrophils migrating across the wall per unit time after the application of fMLP. However, this effect then gradually decreased over the course of 1 h. In the extravascular tissue, the neutrophils appeared to migrate along random pathways with an average trajectory away from the venular wall. When histamine (1 microM) was applied topically in conjunction with fMLP, the overall migratory flux across the venular wall increased, although the cells migrated comparatively short distances into the interstitium. After pretreatment with phalloidin (25 micrograms/kg), an actin cross-linking agent, neutrophil adhesion and migration in response to fMLP stimulation was reduced. The mast cell stimulator 48/80 (25 mg/ml) resulted in rapid degranulation, which was accompanied by an insignificant increase

  11. Labour migration and rural transformation in Nigeria.

    Science.gov (United States)

    Onyeonoru, I P

    1994-06-01

    The trends in rural-urban migration in Nigeria responded to changes in political and socioeconomic developments which occurred during the 1980s. Since the 1980s, rural-urban migration trends were rapidly reversed, and migrants returned to rural areas. In 1981, government revenues from oil declined. The oil production and price declines between 1980 and 1986 resulted in a foreign exchange crisis. Import restrictions were imposed, and stabilization measures resulted in scarcities of raw materials and spare parts and declines in industrial capacity. About 50% of import substitution factories went bankrupt. Between 1981 and 1983, about one million workers were estimated to have been laid off, of which 55,000 were federal and state employees. Other estimates indicated one million laid off just in the industrial sector. The government reinforced this urban-rural movement by emphasizing increased food production. In 1992, government wages were increased in order to offset high inflation. In 1986 and 1992, State and Local Government Areas were established as political entities tied to grassroots development; local offices were situated in greater proximity to local populations. In 1986, the objective was to provide infrastructure, promote production, and organize rural areas for development. Several community banks devoted to rural areas were established. Development programs for rural women were initiated. Federal revenue allocations to rural areas increased from 10% to 15%. Inducements were given to attract private formal and informal commerce and industry. The result was less than expected. Obstacles to rural development included the absence of an effective and integrated approach, inadequate funding, and corruption. Provision of good roads and schools did meet objectives and may have induced out-migration. Delays in provision of entitlements exacerbated the ability of return migrants to establish new economic activity. The new political divisions did not conform to

  12. Migration, Poverty, and the Rural South

    Science.gov (United States)

    Bacon, Lloyd

    1973-01-01

    Employs the 1967 Survey of Economic Opportunity'' data to test hypotheses about differences in migration selectivity depending on the structural distance traversed in the migration process. (Author/JM)

  13. Individual decisions to migrate during civil conflict.

    Science.gov (United States)

    Bohra-Mishra, Pratikshya; Massey, Douglas S

    2011-05-01

    The existing literature on forced migration limits our understanding of how violence affects migration to competing destinations. This article adds to the literature on forced migration by studying how armed violence during a period of civil conflict in south-central Nepal influenced the likelihood of local, internal, and international migration. We find that violence has a nonlinear effect on migration, such that low to moderate levels of violence reduce the odds of movement, but when violence reaches high levels, the odds of movement increase. We also find that the effect of violence on mobility increases as the distance of the move increases. When we consider the influence of violence on microlevel decision-making, we find that the effects of individual and household-level determinants were mostly consistent with hypotheses derived from contemporary theories of voluntary migration and that no predictor of migration influenced the decision to migrate differently in the presence of violence.

  14. Brazilian population 1982: growth, migration, race, religion.

    Science.gov (United States)

    Sanders, T G

    1982-01-01

    The rate of population increase dropped to less than 2.5% annually in Brazil between 1970-80, but 26 million more people were born. The 1980 census also provides details of continuing urbanization, settlement of the farthest frontiers, and changes in racial composition. The direct cause of the drop in population increase was a drop of about 15% in the fertility rate that had been projected for the decade. Brazil's rate of population increase declined impressively despite the fact that the country continued to make progress in reducing mortality. The greatest improvement occurred between 1930-60. The mortality rate averaged 20.9/1000 between 1940-50 but dropped to 14.2/1000 between 1950-60. Even though the crude death rate dropped 28% in the 1970-80 decade and each child born in 1980 can expect to live 6.5 years longer than a child born in 1970, the life expectancy of 62 years compares with Colombia and El Salvador, which are much poorer countries. In Brazil as a whole the crude birthrate in the 15-19 age group was 66/1000 in 1980. It was 46/1000 in 1970, an increase of nearly 50%. In urban areas the rate increased from 37/1000 to 57/1000 and in the countryside from 59/1000 to 89/1000. The crude birthrate went down slightly in Brazil from 1970-80 from 34 to 32/1000. The total fertility rate (TFR) dropped in the same period from 4.9ll to 3.983. The question that arises is whether fertility rates will increase, with women in the youngest age group continuing to have more children during their reproductive years. Internal migration plays a major role in the distribution of the population. Between 1970-80 there were changes in the migration pattern from the previous decade. All the rapidly growing areas, defined as the frontier, have high fertility rates, but much of their growth results from migration. Between 1960-70 and 1970-80 the most rapidly growing areas of the frontier changed. Few are aware of the extent to which Brazil is becoming a country of large cities

  15. Decadal shifts in autumn migration timing by Pacific Arctic beluga whales are related to delayed annual sea ice formation.

    Science.gov (United States)

    Hauser, Donna D W; Laidre, Kristin L; Stafford, Kathleen M; Stern, Harry L; Suydam, Robert S; Richard, Pierre R

    2017-06-01

    Migrations are often influenced by seasonal environmental gradients that are increasingly being altered by climate change. The consequences of rapid changes in Arctic sea ice have the potential to affect migrations of a number of marine species whose timing is temporally matched to seasonal sea ice cover. This topic has not been investigated for Pacific Arctic beluga whales (Delphinapterus leucas) that follow matrilineally maintained autumn migrations in the waters around Alaska and Russia. For the sympatric Eastern Chukchi Sea ('Chukchi') and Eastern Beaufort Sea ('Beaufort') beluga populations, we examined changes in autumn migration timing as related to delayed regional sea ice freeze-up since the 1990s, using two independent data sources (satellite telemetry data and passive acoustics) for both populations. We compared dates of migration between 'early' (1993-2002) and 'late' (2004-2012) tagging periods. During the late tagging period, Chukchi belugas had significantly delayed migrations (by 2 to >4 weeks, depending on location) from the Beaufort and Chukchi seas. Spatial analyses also revealed that departure from Beaufort Sea foraging regions by Chukchi whales was postponed in the late period. Chukchi beluga autumn migration timing occurred significantly later as regional sea ice freeze-up timing became later in the Beaufort, Chukchi, and Bering seas. In contrast, Beaufort belugas did not shift migration timing between periods, nor was migration timing related to freeze-up timing, other than for southward migration at the Bering Strait. Passive acoustic data from 2008 to 2014 provided independent and supplementary support for delayed migration from the Beaufort Sea (4 day yr -1 ) by Chukchi belugas. Here, we report the first phenological study examining beluga whale migrations within the context of their rapidly transforming Pacific Arctic ecosystem, suggesting flexible responses that may enable their persistence yet also complicate predictions of how

  16. DEFINING MIGRATION POLICIES FROM ORIGIN COUNTRY PERSPECTIVE

    OpenAIRE

    Monica SERBAN

    2014-01-01

    The role state plays in international migration gathers more and more attention in migration studies, across different disciplines. Policies implemented in order to manage migration are a point of high interest in the space of destination countries. Yet, even though our knowledge from destination perspective has constantly increased, origin state is still under the shadow of a biased research agenda. We have little insights on the way migration policies at origin are built, enforced or on the...

  17. Migration in Asia-Europe Relations

    OpenAIRE

    Juego, Bonn

    2010-01-01

    There is a remarkable difference between viewing migration as a 'social integration' issue, on the one hand, and migration as a 'social relation'. The idea of ‘social integration’ has unrealistic assumptions that see migration as a one-way process, that societies and human relations are static, and that migrants are mechanical. Policies that are founded on unrealistic assumptions are most likely to generate tensions, conflicts, and contradictions. For a migration process to succeed in forging...

  18. Evolution with Stochastic Fitness and Stochastic Migration

    Science.gov (United States)

    Rice, Sean H.; Papadopoulos, Anthony

    2009-01-01

    Background Migration between local populations plays an important role in evolution - influencing local adaptation, speciation, extinction, and the maintenance of genetic variation. Like other evolutionary mechanisms, migration is a stochastic process, involving both random and deterministic elements. Many models of evolution have incorporated migration, but these have all been based on simplifying assumptions, such as low migration rate, weak selection, or large population size. We thus have no truly general and exact mathematical description of evolution that incorporates migration. Methodology/Principal Findings We derive an exact equation for directional evolution, essentially a stochastic Price equation with migration, that encompasses all processes, both deterministic and stochastic, contributing to directional change in an open population. Using this result, we show that increasing the variance in migration rates reduces the impact of migration relative to selection. This means that models that treat migration as a single parameter tend to be biassed - overestimating the relative impact of immigration. We further show that selection and migration interact in complex ways, one result being that a strategy for which fitness is negatively correlated with migration rates (high fitness when migration is low) will tend to increase in frequency, even if it has lower mean fitness than do other strategies. Finally, we derive an equation for the effective migration rate, which allows some of the complex stochastic processes that we identify to be incorporated into models with a single migration parameter. Conclusions/Significance As has previously been shown with selection, the role of migration in evolution is determined by the entire distributions of immigration and emigration rates, not just by the mean values. The interactions of stochastic migration with stochastic selection produce evolutionary processes that are invisible to deterministic evolutionary theory

  19. Migration, Youth, and Agricultural Productivity in Ethiopia

    OpenAIRE

    Brauw, Alan de

    2015-01-01

    This paper explores the relationship between migration and agricultural productivity in Ethiopia. Given that there are fairly significant returns to either rural-urban or international migration for labor in Ethiopia, it could be that credit constraints hindering migration start-up are an unexplored constraint against migration. The paper primarily uses the Ethiopia Rural Household Survey panel and a migrant listing exercise completed after the 2009 survey round to explore whether past agricu...

  20. Biological aspects of human migration and mobility.

    Science.gov (United States)

    Mascie-Taylor, C G N; Krzyżanowska, M

    2017-08-01

    This paper reviews how migration, both geographical and social, impacts on variation in some human biological traits. Migration and mobility are considered in relation to anthropometric traits and indices, psychometric traits, health, disease and nutrition, temperature regulation and metabolism, mental health and gene flow. It is well known that migration is important in disease transmission but, as this paper demonstrates, migration can have both positive and negative impacts on both donor and recipient populations for a wide range of human traits.

  1. Migration and rural opportunities in Nigeria.

    Science.gov (United States)

    Adepoju, A

    1984-01-01

    This study is concerned with migration to rural areas in Nigeria. The author examines the rural economic structures, social systems, and demographic features affecting such migration. These features are compared for migrants and nonmigrants in the cash cropping and subsistence cropping areas of southwestern Nigeria. The results suggest that rural migration in southwestern Nigeria is mainly urban-rural migration of a colonizing type. Data for the study are from a survey of 1,782 households in 12 villages.

  2. Capitalist development and internal migration in Nigeria.

    Science.gov (United States)

    Akor, R I; Mou, D

    1986-12-01

    The authors analyze internal migration trends in Nigeria by examining individual household strategies and how they have adapted to structural changes brought about by colonial rule and capitalist development. The first section of this article describes the structural changes that started the process of labor migration. The second section deals with post-independence industrialization and the consequent rural-urban migration. The final section analyzes the consequences of these migration patterns for urban growth and rural productivity.

  3. Juridical structures: refugees and migration.

    Science.gov (United States)

    Veiter, T

    1988-01-01

    The juridical problems in regard to the concepts of refugee, expulsion, and migration are complicated. If one speaks about migration in Europe, one must 1st distinguish between Eastern and Western Europe. In the communist states of Eastern Europe the refugee problem does not exist officially, with the only existing refugee problem in Yugoslavia, which has signed and ratified the Geneva Refugee Convention of 1951. In the other East European states the right to asylum exists, but refugees are granted asylum only if they are persecuted in their country of origin for their communist ideas and activities. In speaking of migration, one must distinguish between migration, forced migration, mass migration, emigration, immigration, the shift of populations, and refugees. In the communist countries of Eastern Europe the right to emigration is not respected, although certain exceptions, as in Poland or Yugoslavia do exist. Generally, in the communist states emigration is not allowed and illegal emigration is punished as "Flight from the Republic." With a few exceptions, political and other persecutions are no longer so typical within Europe. In the last decades, the refugee problem has changed to other continents: Afghanistan/Pakistan, Iran, Sri Lanka, East Timor, Lebanon, Palestine, Sudan, Tchad, Ethiopia, Eritrea, and Angola. The refugee problem in Europe consists mainly in the large afflux of refugees coming from places with other cultural (and religious) attributes. The Islamic immigrants declare themselves regularly as political refugees and hope to be acknowledged as such by the receiving state. The fear of the governments and populations of the receiving countries is that it would not be possible to assimilate such aliens who do not belong to the Christian culture of Europe. Formerly, refugees came mostly from the Christian countries of Eastern Europe with the same race identity and the same religion. For years now, more and more foreign workers are a kind of migrant

  4. Step-Wise Migration : Evidence from Indonesia

    NARCIS (Netherlands)

    Pardede, Elda; McCann, Philip; Venhorst, Viktor

    2016-01-01

    The objective of this paper is to study multiple internal migration trajectories in Indonesia, with special attention to step-wise migration. Step-wise migration involves moves with smaller steps from village to nearby small town, to larger town, and then to big cities rather than a direct move from

  5. Migration Flows: Measurement, Analysis and Modeling

    NARCIS (Netherlands)

    Willekens, F.J.; White, Michael J.

    2016-01-01

    This chapter is an introduction to the study of migration flows. It starts with a review of major definition and measurement issues. Comparative studies of migration are particularly difficult because different countries define migration differently and measurement methods are not harmonized.

  6. KIN NETWORKS AND MIGRATION IN SAGBAMA LOCAL ...

    African Journals Online (AJOL)

    CIU

    borders, legally or illegally (IOM, 2003: 14). Personal relations which connect migrants, former migrants and non-migrants with each other in the places of origin and destination increase the probability of international labour migration in connection with circular migration and chain migration processes. As social networks ...

  7. Zimbabwe's Exodus: Crisis, Migration, Survival | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2010-07-01

    Zimbabwe's Exodus: Crisis, Migration, Survival. Book cover Zimbabwe's Exodus: Crisis, Migration, Survival. Editor(s):. Jonathan Crush and Daniel Tevera. Publisher(s):. Southern African Migration Programme, IDRC. July 1, 2010. ISBN: 9781920409227. 420 pages. e-ISBN: 9781552504994. Download PDF · Read the e- ...

  8. Migration, Remittances, and Forest Dependence in Ethiopia ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Migration, Remittances, and Forest Dependence in Ethiopia: Implications for Food Security, Gender, and Forest Conservation. This project will provide evidence that offers important insight into the connection between migration, gender, and forest dependence in rural Ethiopia. Need for labour migration, forest resources ...

  9. [Urban employment and internal migration in Peru].

    Science.gov (United States)

    Cotlear, D

    1984-06-01

    The relationship between internal migration and employment problems in Peru is examined. The author argues that regional differences in income distribution are the primary causes of migration, particularly to urban areas. A model of the migration process is developed and tested using data from official sources, surveys, and the published literature.

  10. The cost of migration: spoonbills suffer higher mortality during trans-Saharan spring migrations only

    NARCIS (Netherlands)

    Lok, T.; Overdijk, O.; Piersma, T.

    2015-01-01

    Explanations for the wide variety of seasonal migration patterns of animals all carry the assumption that migration is costly and that this cost increases with migration distance. Although in some studies, the relationships between migration distance and breeding success or annual survival are

  11. The cost of migration : Spoonbills suffer higher mortality during trans-Saharan spring migrations only

    NARCIS (Netherlands)

    Lok, Tamar; Overdijk, Otto; Piersma, Theunis

    2015-01-01

    Explanations for the wide variety of seasonal migration patterns of animals all carry the assumption that migration is costly and that this cost increases with migration distance. Although in some studies, the relationships between migration distance and breeding success or annual survival are

  12. Japanese Migration and the Americas: An Introduction to the Study of Migration.

    Science.gov (United States)

    Mukai, Gary; Brunette, Rachel

    This curriculum module introduces students to the study of migration, including a brief overview of some categories of migration and reasons why people migrate. As a case study, the module uses the Japanese migration experience in the United States, Peru, Brazil, Canada, Mexico, Argentina, Bolivia, and Paraguay. The module introduces students to…

  13. Self-Selection Patterns in Mexico-U.S. Migration: The Role of Migration Networks

    OpenAIRE

    David McKenzie; Hillel Rapoport

    2010-01-01

    The authors examine the role of migration networks in determining self-selection patterns of Mexico-U.S. migration. They first present a simple theoretical framework showing how such networks impact on migration incentives at different education levels and, consequently, how they are likely to affect the expected skill composition of migration. Using survey data from Mexico, the authors th...

  14. MIGRATION OF ORACLE HR DATABASE

    CERN Multimedia

    ais.support@cern.ch

    2001-01-01

    Restricted services from 3 to 7 November 2001 Due to the migration of the Oracle HR application to the Web, some services which rely on the application's availability may be disturbed from Friday 2 November at 17:30 until Thursday 8 November at 08:30. Amongst those services: HR Division: records office, recruitment, claims and benefits. FI Division: personnel accounting, advances and claims. ST Division: registration office (access cards). SPL Division: external firm staff records. EP Division: users' office. Experiments' secretariats: PIE, Greybook. Divisional secretariats: externals, internal addresses. All information concerning this migration is available at: http://ais.cern.ch We apologize for any inconvenience and thank you in advance for your understanding.

  15. Physicists' Forced Migrations under Hitler

    Science.gov (United States)

    Beyerchen, Alan

    2011-03-01

    When the Nazis came to power in early 1933 they initiated formal and informal measures that forced Jews and political opponents from public institutions such as universities. Some physicists retired and others went into industry, but most emigrated. International communication and contact made emigration a viable option despite the desperate economic times in the Great Depression. Another wave of emigrations followed the annexation of Austria in 1938. Individual cases as well as general patterns of migration and adaptation to new environments will be examined in this presentation. One important result of the forced migrations was that many of the physicists expelled under Hitler played important roles in strengthening physics elsewhere, often on the Allied side in World War II.

  16. Labour Migration and Shadow Prices

    OpenAIRE

    Henry J. Bruton

    1980-01-01

    The effect of migration and home remittances .on the shadow prices of labour and foreign exchange is analysed here, taking into consideration changes in their social marginal productivities.It is argued tha r appreciation of currency, due to large capital inflows and not to increased productivity, results in a misallocation of resources, and, therefore, there is an urgent need for a proper analysis to determine the optimal level of emigrants.

  17. Incentives and disincentives: international migration.

    Science.gov (United States)

    Bhagwati, J N

    1984-01-01

    International migration is largely controlled by disincentives, or quotas, on immigration rather than checks on emigrations. Societies generally feel they have a right to exclude others from their boundaries, but they also usually feel that they do not have a right to control emigration. The single-planetary approach holds that people have the right to live wherever they like on the planet, and the cosmopolitan-utilitarian approach believes the same for reasons of world efficiency. The current feeling that societies have the right to exclude others may be explained best by territoriality in human animals. People also believe that their culture will be diluted if too many outsiders enter. In many cases, immigration systems cannot really control immigration, as in the cases of long landlocked borders between the US and Mexico and between Bangladesh and Assam. Immigration systems also contain legal loopholes. For example, in the US it is easier to get a student visa and convert to immigrant status than to gain immigrant status directly. Loopholes lead to plugs, which lead in turn to more loopholes. An upsurge in requests for political asylum followed increased restrictions on immigration in Western Europe. The US has investigated foreign aid and foreign investments to Mexico and Haiti to curb the flow of illegal migrants. The author suggests that foreign investments may lead to more migration because of the creation of a new proletariat used to the ways of developed countries. An estimate of what would happen if all immigration control were removed worldwide concludes that efficiency and income distribution would improve worldwide. Most migration from developing to developed countries currently consists of the migration of skilled professionals, the brain drain. The author proposes a tax on these professionals to be paid to the country of origin to compensate them for the loss in education and training. The author summarizes the differences between the West German

  18. Asia Strategy on International Migration

    OpenAIRE

    Yasushi Iguchi

    2014-01-01

    Japan needs to develop a strategy for planning and realizing economic integration suitable for Asia. Such a strategy should cover not only liberalization of trade in goods and services and investment but also management of international migration. When developing the strategy, it is important to recognize that since the turn of the century, the leadership of globalization is shifting from developed countries to emerging countries.

  19. Heterogeneous Workers, Trade, and Migration

    OpenAIRE

    Heiland, Inga; Kohler, Wilhelm

    2013-01-01

    We argue that the narrative of variety-induced gains from trade in differentiated goods needs revision. If producing differentiated varieties of a good requires differentiated skills and if the work force is heterogeneous in these skills, then firms are likely to have monopsony power. We show that trade then has adverse labor market effects: It increases the monopsony power of firms and worsens the average quality of matches between firms and workers. We also show that international migration...

  20. Influences of environmental cues, migration history and habitat familiarity on partial migration

    DEFF Research Database (Denmark)

    Skov, Christian; Aarestrup, Kim; Baktoft, Henrik

    2010-01-01

    The factors that drive partial migration in organisms are not fully understood. Roach (Rutilus rutilus), a freshwater fish, engage in partial migration where parts of populations switch between summer habitats in lakes and winter habitats in connected streams. To test if the partial migration trait...... is phenotypically plastic or has genetic components, we translocated roach from 2 populations with different opportunities for migration to a lake with migration opportunity, containing a local roach population. This enabled monitoring of partial migration of fish in 3 different situations: 1) previous opportunity...... in the lake with migration opportunity where from group 2 fish were translocated. Directional migration in and out of the lakes was monitored using Passive Integrated Transponder technology. Translocated fish with previous migration opportunity showed migration patterns more similar to local fish than...

  1. Postnatal Migration of Cerebellar Interneurons

    Directory of Open Access Journals (Sweden)

    Ludovic Galas

    2017-06-01

    Full Text Available Due to its continuing development after birth, the cerebellum represents a unique model for studying the postnatal orchestration of interneuron migration. The combination of fluorescent labeling and ex/in vivo imaging revealed a cellular highway network within cerebellar cortical layers (the external granular layer, the molecular layer, the Purkinje cell layer, and the internal granular layer. During the first two postnatal weeks, saltatory movements, transient stop phases, cell-cell interaction/contact, and degradation of the extracellular matrix mark out the route of cerebellar interneurons, notably granule cells and basket/stellate cells, to their final location. In addition, cortical-layer specific regulatory factors such as neuropeptides (pituitary adenylate cyclase-activating polypeptide (PACAP, somatostatin or proteins (tissue-type plasminogen activator (tPA, insulin growth factor-1 (IGF-1 have been shown to inhibit or stimulate the migratory process of interneurons. These factors show further complexity because somatostatin, PACAP, or tPA have opposite or no effect on interneuron migration depending on which layer or cell type they act upon. External factors originating from environmental conditions (light stimuli, pollutants, nutrients or drug of abuse (alcohol also alter normal cell migration, leading to cerebellar disorders.

  2. SUPER-ECCENTRIC MIGRATING JUPITERS

    Energy Technology Data Exchange (ETDEWEB)

    Socrates, Aristotle; Katz, Boaz; Dong Subo; Tremaine, Scott [Institute for Advanced Study, Princeton, NJ 08540 (United States)

    2012-05-10

    An important class of formation theories for hot Jupiters involves the excitation of extreme orbital eccentricity (e = 0.99 or even larger) followed by tidal dissipation at periastron passage that eventually circularizes the planetary orbit at a period less than 10 days. In a steady state, this mechanism requires the existence of a significant population of super-eccentric (e > 0.9) migrating Jupiters with long orbital periods and periastron distances of only a few stellar radii. For these super-eccentric planets, the periastron is fixed due to conservation of orbital angular momentum and the energy dissipated per orbit is constant, implying that the rate of change in semi-major axis a is a-dot {proportional_to}a{sup 1/2} and consequently the number distribution satisfies dN/d log a{proportional_to}a{sup 1/2}. If this formation process produces most hot Jupiters, Kepler should detect several super-eccentric migrating progenitors of hot Jupiters, allowing for a test of high-eccentricity migration scenarios.

  3. Binaries in Transneptunian Resonances: Evidence for Slow Migration of Neptune?

    Science.gov (United States)

    Noll, Keith

    2012-01-01

    A distinguishing feature of trans neptunian objects (TNO) is the high fraction that arc binary. This is particularly true for the Cold Classicals (CC), objects in lowe and low i orbits concentrated between the 3:2 and 2: 1 mean-motion resonances. CCs have other physical markers: red colors, high albedos, and equal-mass binaries. The CCs appear to be a coherent and physically distinct population of planetesimals that has survived to the present with their physical properties relatively unaltered. Their spatial concentration between 39.4 and 47.7 AU has made identification of the CCs as a physical group possible. However, objects that started out as CCs arc almost certainly 1101 limited to this one dynamical niche. We can, therefore, use the measurable physical properties of CCs as tracers of Neptune-driven dynamical mixing in the Kuiper Belt. As Neptune migrated, its mean-motion resonances preceded it into the planetesimal disk. The efficiency of capture into mean motion resonances depends on the smoothness of Neptune's migration and the local population available to be captured. The two strongest resonances, the 3:2 at 39.4 AU and 2: 1 at 47.7 AU, straddle the core repository of the physically distinct CCs, providing a unique opportunity to test the details of Neptune's migration. Smooth migration should result in a measurable difference between the 3:2 and 2:1 with low inclination 2:1s having a red, binary population mirroring that of the CC itself while the 3:2 will be less contaminated. Alternative models with rapid migration would generate a more homogeneous result.

  4. Why Migrate: For Study or for Work?

    Directory of Open Access Journals (Sweden)

    Elise S. Brezis

    2016-08-01

    Full Text Available Over the past decades, globalization has led to a huge increase in the migration of workers, as well as students. This paper develops a simple two-step model that describes the decisions of an individual vis-à-vis education and migration, and presents a unified model, wherein the two migration decisions are combined into a single, unique model. This paper shows that under the plausible assumption that costs of migration differ over the human life cycle, the usual brain drain strategy is sub-optimal. With an increase in globalization, the brain drain strategy will be replaced by the strategy of migration of students.

  5. Family migration and relative earnings potentials

    DEFF Research Database (Denmark)

    Foged, Mette

    2016-01-01

    A unitarian model of family migration in which families may discount wives’ private gains is used to derive testable predictions regarding the type of couples that select into migrating. The empirical tests show that gender neutral family migration cannot be rejected against the alternative...... of husband centered migration. Couples are more likely to migrate if household earnings potential is disproportionally due to one partner, and families react equally strongly to a male and a female relative advantage in educational earnings potential. These results are driven by households with a strong...

  6. Influences of environmental cues, migration history, and habitat familiarity on partial migration

    OpenAIRE

    Christian Skov; Kim Aarestrup; Henrik Baktoft; Jakob Brodersen; Christer Brönmark; Lars-Anders Hansson; Nielsen, Einar E.; Tine Nielsen; P Anders Nilsson

    2010-01-01

    The factors that drive partial migration in organisms are not fully understood. Roach (Rutilus rutilus), a freshwater fish, engage in partial migration where parts of populations switch between summer habitats in lakes and winter habitats in connected streams. To test if the partial migration trait is phenotypically plastic or has genetic components, we translocated roach from 2 populations with different opportunities for migration to a lake with migration opportunity, containing a local roa...

  7. Tectonic control in source rock maturation and oil migration in Trinidad

    Energy Technology Data Exchange (ETDEWEB)

    Persad, K.M.; Talukdar, S.C.; Dow, W.G. (DGSI, The Woodlands, TX (United States))

    1993-02-01

    Oil accumulation in Trinidad were sourced by the Upper Cretaceous calcareous shales deposited along the Cretaceous passive margin of northern South America. Maturation of these source rocks, oil generation, migration and re-migration occurred in a foreland basin setting that resulted from interaction between Caribbean and South American plates during Late Oligocene to recent times. During Middle Miocene-Recent times, the foreland basin experienced strong compressional events, which controlled generation, migration, and accumulation of oil in Trinidad. A series of mature source rock kitchens formed in Late Miocene-Recent times in the Southern and Colombus Basins to the east-southeast of the Central Range Thrust. This thrust and associated fratured developed around 12 m.y.b.p. and served as vertical migration paths for the oil generated in Late Miocene time. This oil migrated into submarine fans deposited in the foreland basin axis and older reservoirs deformed into structural traps. Further generation and migration of oil, and re-migration of earlier oil took place during Pliocene-Holocene times, when later thrusting and wrench faulting served as vertical migration paths. Extremely high sedimentation rates in Pliocene-Pleistocene time, concurrent with active faulting, was responsible for very rapid generation of oil and gas. Vertically migrating gas often mixed with earlier migrated oil in overlying reservoirs. This caused depletion of oil in light hydrocarbons with accompanied fractionation among hydrocarbon types resulting in heavier oil in lower reservoirs, enrichment of light hydrocarbons and accumulation of gas-condensates in upper reservoirs. This process led to an oil-gravity stratification within about 10,000 ft of section.

  8. Antioxidant migration resistance of SiOxlayer in SiOx/PLA coated film.

    Science.gov (United States)

    Huang, Chongxing; Zhao, Yuan; Su, Hongxia; Bei, Ronghua

    2018-02-01

    As novel materials for food contact packaging, inorganic silicon oxide (SiO x ) films are high barrier property materials that have been developed rapidly and have attracted the attention of many manufacturers. For the safe use of SiO x films for food packaging it is vital to study the interaction between SiO x layers and food contaminants, as well as the function of a SiO x barrier layer in antioxidant migration resistance. In this study, we deposited a SiO x layer on polylactic acid (PLA)-based films to prepare SiO x /PLA coated films by plasma-enhanced chemical vapour deposition. Additionally, we compared PLA-based films and SiO x /PLA coated films in terms of the migration of different antioxidants (e.g. t-butylhydroquinone [TBHQ], butylated hydroxyanisole [BHA], and butylated hydroxytoluene [BHT]) via specific migration experiments and then investigated the effects of a SiO x layer on antioxidant migration under different conditions. The results indicate that antioxidant migration from SiO x /PLA coated films is similar to that for PLA-based films: with increase of temperature, decrease of food simulant polarity, and increase of single-sided contact time, the antioxidant migration rate and amount in SiO x /PLA coated films increase. The SiO x barrier layer significantly reduced the amount of migration of antioxidants with small and similar molecular weights and similar physical and chemical properties, while the degree of migration blocking was not significantly different among the studied antioxidants. However, the migration was affected by temperature and food simulant. Depending on the food simulants considered, the migration amount in SiO x /PLA coated films was reduced compared with that in PLA-based films by 42-46%, 44-47%, and 44-46% for TBHQ, BHA, and BHT, respectively.

  9. Proteolytic and non-proteolytic migration of tumour cells and leucocytes.

    Science.gov (United States)

    Friedl, Peter; Wolf, Katarina

    2003-01-01

    The migration of different cell types, such as leucocytes and tumour cells, involves cellular strategies to overcome the physical resistance of three-dimensional tissue networks, including proteolytic degradation of extracellular matrix (ECM) components. High-resolution live-cell imaging techniques have recently provided structural and biochemical insight into the differential use of matrix-degrading enzymes in the migration processes of different cell types within the three-dimensional ECM. Proteolytic migration is achieved by slow-moving cells, such as fibroblasts and mesenchymally moving tumour cells, by engaging matrix metalloproteinases, cathepsins and serine proteases at the cell surface in a focalized manner ('pericellular proteolysis'), while adhesion and migratory traction are provided by integrins. Pericellular breakdown of ECM components generates localized matrix defects and remodelling along migration tracks. In contrast with tumour cells, constitutive non-proteolytic migration is used by rapidly moving T lymphocytes. This migration type does not generate proteolytic matrix remodelling, but rather depends on shape change to allow cells to glide and squeeze through gaps and trails present in connective tissues. In addition, constitutive proteolytic migration can be converted into non-proteolytic movement by protease inhibitors. After the simultaneous inhibition of matrix metalloproteinases, serine/threonine proteases and cysteine proteases in tumour cells undergoing proteolysis-dependent movement, a fundamental adaptation towards amoeboid movement is able to sustain non-proteolytic migration in these tumour cells (the mesenchymal-amoeboid transition). Instead of using proteases for matrix degradation, the tumour cells use leucoyte-like strategies of shape change and squeezing through matrix gaps along tissue scaffolds. The diversity of protease function in cell migration by different cell types highlights response diversity and molecular adaptation of

  10. Rapid quantitation of neutrophil chemotaxis: use of a polyvinylpyrrolidone-free polycarbonate membrane in a multiwell assembly

    OpenAIRE

    Harvath, L.; Falk, Werner; Leonard, E J

    1980-01-01

    A neutrophil chemotaxis assay was developd which permits rapid, quantitative assessment of migration across a membrane filter. The critical factor in the assay was the use of a 10 microns thick polycarbonate membrane without the usual polyvinylpyrrolidone coating. Migrated neutrophils remain adherent to the uncoated membrane, whereas 20-50% fall off polyvinylpyrrolidone-coated membranes. A major advantage of the method is that neutrophil chemotaxis can be readily quantified, since the migrate...

  11. Rapid Prototyping Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The ARDEC Rapid Prototyping (RP) Laboratory was established in December 1992 to provide low cost RP capabilities to the ARDEC engineering community. The Stratasys,...

  12. Emerging Transnational migration from Romanian villages

    Directory of Open Access Journals (Sweden)

    Dumitru Sandu

    2014-11-01

    Full Text Available This article presents the first results of a community census (December 2001 on temporary external migration at the level of all Romanian villages. Local key informants filled in the questionnaire on international temporary migration and its sociodemographic profile. As function of the key destinations, the Romanian villages cluster into six major migration fields: Germany, Hungary, Italy, Turkey, Yugoslavia and Spain. At a more detailed level, considering multiple destinations, those fields break into 15 regions of migration.Village-level analysis of the phenomenon indicates a strong selectivity of migration depending on village characteristics. About 4 percent of the total villages of the country account for more than 60 percent of the total return migration from abroad. These are villages of a high probability of transnationalism. Circular or transnational migration is shown to be connected with the basic characteristics of the migration system of the country: the villages where village to city commuting declined sharply after 1990 and where return migration from cities was high recorded a higher propensity for circular migration abroad. A set of about 2700 villages of high migration prevalence is described as «probable transnational communities».

  13. An economic analysis of migration in Mexico.

    Science.gov (United States)

    Greenwood, M J; Ladman, J R

    1978-07-01

    This paper analyzes internal migration in Mexico over the 1960-70 period. A model of the determinants of migration is specified and estimated for aggregated interstate migration flows. Results show that distance serves as a significant deterrent to migration, that higher destination earning levels are attractive to migrants, and that regions with high unemployment rates experience lower rates of inmigration. An unanticipated finding is that regions with higher earning levels have greater rates of outmigration. The data are disaggregated to examine separate migration relationships for each state. The results are that distance is a lesser deterrent for those migrants with more accessible alternatives, that higher earning levels reduce the deterring effects of distance, and that regions with higher earning levels have lower associated elasticities of migration. It is concluded that economic factors have played a crucial role in internal migration and thus in the changing occupational and geographic structure of the Mexican labor force.

  14. Partial migration in fishes: causes and consequences

    DEFF Research Database (Denmark)

    Chapman, B.B.; Hulthén, K.; Brodersen, J.

    2012-01-01

    Partial migration, where only some individuals from a population migrate, has been widely reported in a diverse range of animals. In this paper, what is known about the causes and consequences of partial migration in fishes is reviewed. Firstly, the ultimate and proximate drivers of partial...... migration are reflected upon: what ecological factors can shape the evolution of migratory dimorphism? How is partial migration maintained over evolutionary timescales? What proximate mechanisms determine whether an individual is migratory or remains resident? Following this, the consequences of partial...... migration are considered, in an ecological and evolutionary context, and also in an applied sense. Here it is argued that understanding the concept of partial migration is crucial for fisheries and ecosystem managers, and can provide information for conservation strategies. The review concludes...

  15. Migration from New EU Member Countries

    DEFF Research Database (Denmark)

    Pytlikova, Mariola

    2007-01-01

    The main purpose of the paper is to give predictions of the migration potential from the 7 new EU member countries to the EEA/EU-13 countries. Being able to analyze 'real' migration behavior from these particular countries over the period 1990-2000 helps me to avoid problems related to (double) out......-of sample forecasts and to the assumption of invariance of migration behavior across a space that previous studies had to hold. Results of the econometric analyses reveal the importance of controlling for pairs of countries unobserved heterogeneity. Preliminary results regarding the predictions of future...... gross and net migration flows show that the magnitude of the estimated gross and net migration flows is relatively high and lower, respectively, compared to forecasts from previous studies. Such a development in gross and net migration flows indicates that migration from the new EU member countries...

  16. Migration of iron, lead, cadmium and tin from tinplate-coated cans into chickpeas.

    Science.gov (United States)

    Kassouf, A; Chebib, H; Lebbos, N; Ouaini, R

    2013-01-01

    Migration studies of trace metals were carried out on coated chickpea cans marketed in Lebanon. Four elements--(Fe), tin (Sn), lead (Pb) and cadmium (Cd)--were analysed by atomic absorption spectrometry (AAS) after microwave digestion. Over 3 months, three different storage temperatures (5°C, room temperature and 40°C) were tested. In all cases, the migration of Fe reached a plateau after around 50 days of storage, while the migration of Pb was slow till 50 days, then it increased rapidly. Cd and Sn levels did not increase. Moreover, no effect of temperature was observed in the case of Fe, whereas Pb levels showed slower migration in cans stored at 5°C. Comparing cans from different chickpea brands (Lebanese and foreign) showed that the characteristics of the container have an effect on metal release.

  17. Experience drives innovation of new migration patterns of whooping cranes in response to global change

    Science.gov (United States)

    Teitelbaum, Claire S; Converse, Sarah J.; Fagan, William F.; Böhning-Gaese, Katrin; O'Hara, Robert B.; Lacy, Anne E; Mueller, Thomas

    2016-01-01

    Anthropogenic changes in climate and land use are driving changes in migration patterns of birds worldwide. Spatial changes in migration have been related to long-term temperature trends, but the intrinsic mechanisms by which migratory species adapt to environmental change remain largely unexplored. We show that, for a long-lived social species, older birds with more experience are critical for innovating new migration behaviours. Groups containing older, more experienced individuals establish new overwintering sites closer to the breeding grounds, leading to a rapid population-level shift in migration patterns. Furthermore, these new overwintering sites are in areas where changes in climate have increased temperatures and where food availability from agriculture is high, creating favourable conditions for overwintering. Our results reveal that the age structure of populations is critical for the behavioural mechanisms that allow species to adapt to global change, particularly for long-lived animals, where changes in behaviour can occur faster than evolution.

  18. Ontogenetic development of migration: Lagrangian drift trajectories suggest a new paradigm for sea turtles

    DEFF Research Database (Denmark)

    Hays, Graeme C.; Fossette, Sabrina; Katselidis, Kostas A.

    2010-01-01

    Long distance migration occurs in a wide variety of taxa including birds, insects, fishes, mammals and reptiles. Here, we provide evidence for a new paradigm for the determinants of migration destination. As adults, sea turtles show fidelity to their natal nesting areas and then at the end...... of the breeding season may migrate to distant foraging sites. For a major rookery in the Mediterranean, we simulated hatchling drift by releasing 288 000 numerical particles in an area close to the nesting beaches. We show that the pattern of adult dispersion from the breeding area reflects the extent of passive...... dispersion that would be experienced by hatchlings. Hence, the prevailing oceanography around nesting areas may be crucial to the selection of foraging sites used by adult sea turtles. This environmental forcing may allow the rapid evolution of new migration destinations if ocean currents alter with climate...

  19. Bleb Expansion in Migrating Cells Depends on Supply of Membrane from Cell Surface Invaginations.

    Science.gov (United States)

    Goudarzi, Mohammad; Tarbashevich, Katsiaryna; Mildner, Karina; Begemann, Isabell; Garcia, Jamie; Paksa, Azadeh; Reichman-Fried, Michal; Mahabaleshwar, Harsha; Blaser, Heiko; Hartwig, Johannes; Zeuschner, Dagmar; Galic, Milos; Bagnat, Michel; Betz, Timo; Raz, Erez

    2017-12-04

    Cell migration is essential for morphogenesis, organ formation, and homeostasis, with relevance for clinical conditions. The migration of primordial germ cells (PGCs) is a useful model for studying this process in the context of the developing embryo. Zebrafish PGC migration depends on the formation of cellular protrusions in form of blebs, a type of protrusion found in various cell types. Here we report on the mechanisms allowing the inflation of the membrane during bleb formation. We show that the rapid expansion of the protrusion depends on membrane invaginations that are localized preferentially at the cell front. The formation of these invaginations requires the function of Cdc42, and their unfolding allows bleb inflation and dynamic cell-shape changes performed by migrating cells. Inhibiting the formation and release of the invaginations strongly interfered with bleb formation, cell motility, and the ability of the cells to reach their target. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. A LONGITUDINAL ANALYSIS OF INTERNAL MIGRATION, DIVORCE AND WELL-BEING IN CHINA.

    Science.gov (United States)

    Bhargava, Alok; Tan, Xiayun

    2017-10-09

    The rapid economic growth in China has been accompanied by increases in internal migration as well as marital dissolution. Using longitudinal data from China Health and Nutrition Surveys covering over 19,000 individuals during 1989-2011, this study modelled the inter-relationships between internal migration, divorce and individual well-being, tackling conceptual and methodological aspects such as the joint determination of variables. First, random effects probit models showed that the migration periods of husbands and wives significantly increased their respective chances of divorce. Second, results from dynamic random effects models for self-reported health showed different effects of separation periods for husbands and wives; divorce did not significantly lower health status. Third, dynamic models for systolic and diastolic blood pressures showed significant effects of migration durations of husbands and wives; men had lower systolic blood pressure following divorce thereby indicating beneficial effects for unhappily married couples. The implications of the findings are discussed.

  1. Korean nursing students' intention to migrate abroad.

    Science.gov (United States)

    Lee, Eunjoo; Moon, Mikyung

    2013-12-01

    Migration of Korean nurses has continued with changing patterns and reasons. However, detailed studies of migration among Korean nursing students are limited. This study examined the intention, reasons, and preferences of migration among Korean nursing students. This study also identified priorities and barriers to the decision of nursing students to migrate and work abroad. A descriptive study using a questionnaire was used for this study. A total of 717 nursing students from four BSN programs and three diploma programs at nursing schools in D city and K province of South Korea were included in the analysis. According to the results, 69.8% of respondents intended to migrate abroad, if possible, or absolutely in the future. The score for females who answered "yes, if possible" regarding the intention to migrate was significantly higher, compared to males. More than 64% of respondents eventually want to return to Korea after migration. The two most common reasons for migration were economic reason (salary) (29.7%) and "professional development (28.2%)". Half of all respondents preferred the US as the destination country of migration (50.5%). "Working condition" was the most prevalent reason for the decision regarding the destination and the place to work. More than 71% of respondents selected "the lack of language proficiency" as a barrier to migration. Economic reason was not as strong as in the past to explain migration of Korean nursing students. Most Korean nursing students want to return back with professional development and higher degree. Even permanent migration and return migration of nurses are an inevitable part of globalization, positive and negative aspects of migration between donor as well as destination countries should be investigated. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. The Influence of Complexation on Radionuclide Migration: A Theoretical Study

    DEFF Research Database (Denmark)

    Carlsen, L.; Nielsen, O.J.; Bo, P.

    1989-01-01

    -order kinetics. It is shown that as long as the rate of interconversion between the free and complexed metal ions is rapid relative to the residence time in the system studied, the two species will migrate with the same speed, controlled by an "effective retention factor." It is clearly demonstrated...... that approaching zero complexation the effective retention approaches that of the more retarded species (the free metal ion), whereas the effective retention approached that of the less retarded species (the complex) for increased complexation. The implication for the distribution of radionuclides...

  3. Population genetic analysis infers mMigration pathways of Phytophthora ramorum in US nurseries

    Science.gov (United States)

    Erica M. Goss; Meg Larsen; Gary A. Chastagner; Donald R. Givens; Niklaus J. Grünwald; Barbara Jane Howlett

    2009-01-01

    Recently introduced, exotic plant pathogens may exhibit low genetic diversity and be limited to clonal reproduction. However, rapidly mutating molecular markers such as microsatellites can reveal genetic variation within these populations and be used to model putative migration patterns. Phytophthora ramorum is the exotic pathogen, discovered in...

  4. Return migration as failure or success? : The determinants of return migration intentions among Moroccan migrants in Europe

    NARCIS (Netherlands)

    de Haas, H.; Fokkema, T.; Fihri, M.F.

    2015-01-01

    Different migration theories generate competing hypotheses with regard to determinants of return migration. While neoclassical migration theory associates migration to the failure to integrate at the destination, the new economics of labour migration sees return migration as the logical stage after

  5. Migration, Acculturation and Political Values

    Directory of Open Access Journals (Sweden)

    Cristian Bocancea

    2011-12-01

    Full Text Available Contemporary migration flows create deep processes of acculturation whose consistency, stability and finality are based on a symbolical and subjective arsenal, represented by the democratic values promoted by the Western world. Besides the demographic and economic changes brought by the current population movements (real or virtual there is also a noticeable cultural change which affects the depths of societies (regardless of whether these movements are emigrations or immigrations and which refer to the birth or the consolidation of a lifestyle based on the aspiration to prosperity, personal freedom and democracy, beyond racial, ethnic, religious, etc. differences.

  6. Migrating Applications to IPv6

    CERN Document Server

    York, Dan

    2011-01-01

    If IPv6 is to be adopted on a large scale, the applications running on desktop systems, laptops, and even mobile devices need to work just as well with this protocol as they do with IPv4. This concise book takes you beyond the network layer and helps you explore the issues you need to address if you are to successfully migrate your apps to IPv6. It's ideal for application developers, system/network architects, product managers, and others involved in moving your network to IPv6. Explore changes you need to make in your application's user interfaceMake sure your application is retrieving corre

  7. Genre et migration au Liban

    OpenAIRE

    JOUNI, Hassan

    2011-01-01

    Euro-Mediterranean Consortium for Applied Research on International Migration (CARIM) La femme possède un statut bien avancé au sein de la société libanaise : la Constitution libanaise proclame l’égalité entre les citoyens. Quelques lois et pratiques restent, toutefois, discriminatoires à l’égard de la femme, notamment la loi sur la nationalité et la loi sur le statut personnel. Une discrimination sociale très grave existe en ce qui concerne les femmes travaillant à domicile; elles subi...

  8. Giant Planet Formation and Migration

    Science.gov (United States)

    Paardekooper, Sijme-Jan; Johansen, Anders

    2018-02-01

    Planets form in circumstellar discs around young stars. Starting with sub-micron sized dust particles, giant planet formation is all about growing 14 orders of magnitude in size. It has become increasingly clear over the past decades that during all stages of giant planet formation, the building blocks are extremely mobile and can change their semimajor axis by substantial amounts. In this chapter, we aim to give a basic overview of the physical processes thought to govern giant planet formation and migration, and to highlight possible links to water delivery.

  9. Asian student migration to Australia.

    Science.gov (United States)

    Shu, J; Hawthorne, L

    1996-01-01

    "This paper presents an overview of Asian student migration to Australia, together with an analysis of political and educational aspects of the overseas student programme. It focuses on some significant consequences of this flow for Australia. The characteristics of key student groups are contrasted to provide some perspective of the diversity of historical and cultural backgrounds, with the source countries of Malaysia, Indonesia and PRC [China] selected as case studies. Since the issue of PRC students in Australia has attracted considerable public attention and policy consideration, particular focus is placed on their experience." (SUMMARY IN FRE AND SPA) excerpt

  10. AHP 40:THE MOUNTAIN CHANGERS: LIFESTYLE MIGRATION IN SOUTHWEST CHINA

    Directory of Open Access Journals (Sweden)

    Gary Sigley

    2016-02-01

    Full Text Available In the early twenty-first century, the People's Republic of China (PRC continues its remarkable transformation that encompasses all facets of social life. One of the most significant, visible forms of such change is urbanization. Chinese cities are rapidly expanding and, according to some reports, will grow by a staggering 400 million people over the next several decades. In just under forty years China will have transformed from a predominantly rural to urban society, a pace of urbanization not matched in previous human experience. Yet while migration in China has in recent decades been overwhelmingly of people moving from the countryside to the city, and to a lesser extent (but also quite large given the size of China's population migration of more well educated urbanites and professionals between cities, there has been a small flow of people in the other direction, that is, of those leaving the metropolises of the eastern seaboard to seek out alternative lifestyles in the mountains of western China, and in particular to places like Yunnan in the southwest. These are akin to the "sea changers" and "tree changers" found in more affluent Western societies and can be included in the relatively new phenomenon of "lifestyle migration." This paper provides a preliminary overview of this phenomenon in the context of Dali, a prefectural city in Yunnan Province.

  11. Rapid Airplane Parametric Input Design (RAPID)

    Science.gov (United States)

    Smith, Robert E.

    1995-01-01

    RAPID is a methodology and software system to define a class of airplane configurations and directly evaluate surface grids, volume grids, and grid sensitivity on and about the configurations. A distinguishing characteristic which separates RAPID from other airplane surface modellers is that the output grids and grid sensitivity are directly applicable in CFD analysis. A small set of design parameters and grid control parameters govern the process which is incorporated into interactive software for 'real time' visual analysis and into batch software for the application of optimization technology. The computed surface grids and volume grids are suitable for a wide range of Computational Fluid Dynamics (CFD) simulation. The general airplane configuration has wing, fuselage, horizontal tail, and vertical tail components. The double-delta wing and tail components are manifested by solving a fourth order partial differential equation (PDE) subject to Dirichlet and Neumann boundary conditions. The design parameters are incorporated into the boundary conditions and therefore govern the shapes of the surfaces. The PDE solution yields a smooth transition between boundaries. Surface grids suitable for CFD calculation are created by establishing an H-type topology about the configuration and incorporating grid spacing functions in the PDE equation for the lifting components and the fuselage definition equations. User specified grid parameters govern the location and degree of grid concentration. A two-block volume grid about a configuration is calculated using the Control Point Form (CPF) technique. The interactive software, which runs on Silicon Graphics IRIS workstations, allows design parameters to be continuously varied and the resulting surface grid to be observed in real time. The batch software computes both the surface and volume grids and also computes the sensitivity of the output grid with respect to the input design parameters by applying the precompiler tool

  12. Political motivations for intra-European migration.

    Science.gov (United States)

    Bygnes, Susanne; Flipo, Aurore

    2017-08-01

    Motivations for migrating within the European Union have mainly been attributed to economic, career and lifestyle choices. This article suggests that political dissatisfaction is also an important motivator of recent intra-European migration. In our analysis of in-depth interviews with Romanian migrants in Spain and with Spanish migrants in Norway, we found a common emphasis on the political dimensions of their decision to migrate. In the interviews, the economic component of migration was often related to bad governance and negative perceptions of the state. The similarities of Spanish and Romanian migration narratives are especially striking because Spain and Romania represent substantially different migratory, political and economic contexts. However, migration is more obviously intertwined with conventional acts of political protest in the Spanish case. We suggest that differences in democratic contexts are pivotal in people's reactions to and framing of their deep dissatisfaction with domestic politics, as found in many European countries today.

  13. Migration in Asia-Europe Relations

    DEFF Research Database (Denmark)

    Juego, Bonn

    2010-01-01

    There is a remarkable difference between viewing migration as a 'social integration' issue, on the one hand, and migration as a 'social relation'. The idea of ‘social integration’ has unrealistic assumptions that see migration as a one-way process, that societies and human relations are static......, and that migrants are mechanical. Policies that are founded on unrealistic assumptions are most likely to generate tensions, conflicts, and contradictions. For a migration process to succeed in forging social harmony and development, it is therefore of decisive and crucial importance to regard migration...... as a ‘social relation’. This is simply because successful migration has to be a harmonious synergy between the migrants (and also the sending countries where they come from) and the receiving society (and its people). As indicated, migrants enter into the receiving society not merely as a passive commodity...

  14. Integrin-mediated cell surface recruitment of autotaxin promotes persistent directional cell migration

    Science.gov (United States)

    Wu, Tao; Kooi, Craig Vander; Shah, Pritom; Charnigo, Richard; Huang, Cai; Smyth, Susan S.; Morris, Andrew J.

    2014-01-01

    Autotaxin (ATX) is a secreted lysophospholipase D (lysoPLD) that binds to integrin adhesion receptors. We dissected the roles of integrin binding and lysoPLD activity in stimulation of human breast cancer and mouse aortic vascular smooth muscle cell migration by ATX. We compared effects of wild-type human ATX, catalytically inactive ATX, an integrin binding-defective ATX variant with wild-type lysoPLD activity, the isolated ATX integrin binding N-terminal domain, and a potent ATX selective lysoPLD inhibitor on cell migration using transwell and single-cell tracking assays. Stimulation of transwell migration was reduced (18 or 27% of control, respectively) but not ablated by inactivation of integrin binding or inhibition of lysoPLD activity. The N-terminal domain increased transwell migration (30% of control). ATX lysoPLD activity and integrin binding were necessary for a 3.8-fold increase in the fraction of migrating breast cancer cell step velocities >0.7 μm/min. ATX increased the persistent directionality of single-cell migration 2-fold. This effect was lysoPLD activity independent and recapitulated by the integrin binding N-terminal domain. Integrin binding enables uptake and intracellular sequestration of ATX, which redistributes to the front of migrating cells. ATX binding to integrins and lysoPLD activity therefore cooperate to promote rapid persistent directional cell migration.—Wu, T., Kooi, C. V., Shah, P., Charnigo, R., Huang, C., Smyth, S. S., Morris, A. J. Integrin-mediated cell surface recruitment of autotaxin promotes persistent directional cell migration. PMID:24277575

  15. Specific migration of IRGASTAB 17 MOK and DBP from rigid and plasticized poly(vinyl chloride into organic liquids

    Directory of Open Access Journals (Sweden)

    Amara A.

    2013-07-01

    Full Text Available The aim of this paper is the determination of the specific migration of an plasticizer and an organotin heat stabilizer (IRGASTAB 17 MOK from plasticized and rigid (PVC into organic liquids hexane and ethanol simulating fatty food. The migration test conditions were 10 days at 40°C and 2 hours at 70°C. FTIR and UV-Visible at 490 nm spectroscopy and gas chromatography were used to investigate the migration phenomena. The influence of various parameters such as temperature, time of contact and the nature of food simulant were considered. The results show that plasticizer accelerates the heat stabilizer migration. On the other hand that gas chromatography could be substituted by FTIR spectroscopy to investigate the DBP migration phenomena. It is a simple, low cost and rapid method which can be used.

  16. The trade, migration, and development nexus

    OpenAIRE

    Philip L. Martin

    2006-01-01

    This paper deals with migrants' role in stimulating development in their countries of origin, outlining the three major channels through which migration can affect development: recruitment, remittances, and returns. It next turns to the North American Free Trade Agreement (NAFTA), assessing the relevance of the Mexico-United States migration hump for migration, trade, and development elsewhere. The paper concludes that migrants can accelerate development in their countries of origin but finds...

  17. Essays of Economic Development and Migration

    OpenAIRE

    Kleemans, Maria Adriaantje

    2015-01-01

    This dissertation is composed of three chapters and studies issues related to economic development and migration. The first chapter looks at migration choice in an environment where people face risk and liquidity constraints. The second chapter, which is co-authored with Jeremy Magruder, studies the labor market impact of immigration in Indonesia. The third chapter is written together with Joan Hamory Hick and Edward Miguel and examines selection into migration in Kenya.The first paper dev...

  18. Navigational Strategies of Migrating Monarch Butterflies

    Science.gov (United States)

    2014-11-10

    AFRL-OSR-VA-TR-2014-0339 NAVIGATIONAL STRATEGIES OF MIGRATING MONARCH BUTTERFLIES Steven Reppert UNIVERSITY OF MASSACHUSETTS Final Report 11/10/2014...Final Progress Statement to (Dr. Patrick Bradshaw) Contract/Grant Title: Navigational Strategies of Migrating Monarch Butterflies Contract...Grant #: FA9550-10-1-0480 Reporting Period: 01-Sept-10 to 31-Aug-14 Overview of accomplishments: Migrating monarch butterflies (Danaus

  19. [Big-city migration in historical perspective].

    Science.gov (United States)

    Croes, M M; Van Huis, L T

    1997-01-01

    "The migration flows to and from the four largest Dutch municipalities (Amsterdam, Rotterdam, The Hague and Utrecht) show a number of similarities. During the past few decades internal migration has been characterized by a move away from the large cities, while the much smaller international migration flow had an opposite direction. This has resulted in a net decrease of the total population in the largest cities." (SUMMARY IN ENG) excerpt

  20. Inter-Religious Marriage and Migration

    OpenAIRE

    Bohm, Maggie Y

    2008-01-01

    This study analyzes the influence of 1) inter-religious marriage and 2) differing levels of church attendance within a married couple on migration behavior. The study draws from previous research on inter-racial marriage for a framework to examine whether there is reason to expect a relationship between migration and inter-religious marriage. We hypothesize that the propensity for migration is higher for inter-religious couples than for couples constituted by individuals of the same religion ...

  1. Elastic least-squares reverse time migration

    KAUST Repository

    Feng, Zongcai

    2016-09-06

    Elastic least-squares reverse time migration (LSRTM) is used to invert synthetic particle-velocity data and crosswell pressure field data. The migration images consist of both the P- and Svelocity perturbation images. Numerical tests on synthetic and field data illustrate the advantages of elastic LSRTM over elastic reverse time migration (RTM). In addition, elastic LSRTM images are better focused and have better reflector continuity than do the acoustic LSRTM images.

  2. Rapid shallow breathing

    Science.gov (United States)

    ... the smallest air passages of the lungs in children ( bronchiolitis ) Pneumonia or other lung infection Transient tachypnea of the newborn Anxiety and panic Other serious lung disease Home Care Rapid, shallow breathing should not be treated at home. It is ...

  3. Rapid Strep Test

    Science.gov (United States)

    ... worse than normal. Your first thoughts turn to strep throat. A rapid strep test in your doctor’s office ... your suspicions.Viruses cause most sore throats. However, strep throat is an infection caused by the Group A ...

  4. Nuss bar migrations: occurrence and classification

    Energy Technology Data Exchange (ETDEWEB)

    Binkovitz, Lauren E.; Binkovitz, Larry A. [Mayo Clinic, Department of Radiology, Rochester, MN (United States); Zendejas, Benjamin; Moir, Christopher R. [Mayo Clinic, Department of Surgery, Rochester, MN (United States)

    2016-12-15

    Pectus excavatum results from dorsal deviation of the sternum causing narrowing of the anterior-posterior diameter of the chest. It can result in significant cosmetic deformities and cardiopulmonary compromise if severe. The Nuss procedure is a minimally invasive technique that involves placing a thin horizontally oriented metal bar below the dorsal sternal apex for correction of the pectus deformity. To identify the frequency and types of Nuss bar migrations, to present a new categorization of bar migrations, and to present examples of true migrations and pseudomigrations. We retrospectively reviewed the electronic medical records and all pertinent radiologic studies of 311 pediatric patients who underwent a Nuss procedure. We evaluated the frequency and type of bar migrations. Bar migration was demonstrated in 23 of 311 patients (7%) and occurred within a mean period of 26 days after surgery. Bar migrations were subjectively defined as deviation of the bar from the position demonstrated on the immediate postoperative radiographs and categorized as superior, inferior, rotation, lateral or flipped using a new classification system. Sixteen of the 23 migrations required re-operation. Nuss bar migration can be diagnosed with careful evaluation of serial radiographs. Nuss bar migration has a wide variety of appearances and requires exclusion of pseudomigration resulting from changes in patient positioning between radiologic examinations. (orig.)

  5. The role of language in international migration

    DEFF Research Database (Denmark)

    Adsera, Alicia; Pytlikova, Mariola

    in shaping international migration. Specifically, we investigate how both linguistic distance and linguistic diversity, as a proxy for the “potential” ease to learn a new language and to adapt to a new context, affect migration. We find that migration rates increase with linguistic proximity and the result...... a foreign language might be an important factor in the migration decision. We use a novel dataset on immigration flows and stocks of foreigners in 30 OECD destination countries from 223 source countries for the years 1980–2009 and a wide range of linguistic indicators to study the role of language...

  6. Dust Migration in Gravitationally Active Protoplanetary Disks

    Science.gov (United States)

    Backus, I.; Quinn, T.

    2017-05-01

    Solid growth and planet formation may require dense regions of dust. I investigate dust migration concentration, in gravitationally active protoplanetary disks using high resolution, 3D SPH simulations.

  7. Investigation of acetyl migrations in furanosides

    National Research Council Canada - National Science Library

    Chevallier, O P; Migaud, M E

    2006-01-01

    ...) derivatives facilitate acyl migration. Conditions which favour intramolecular and intermolecular mechanisms have been identified with intermolecular transesterifications taking place under mild basic conditions when intramolecular...

  8. Migration processes in SCO member states

    Directory of Open Access Journals (Sweden)

    Valentina Sergeevna Antonyuk

    2012-12-01

    Full Text Available The article concerns modern state and development of migration processes in SCO member states. As a main method of research statistical analysis was applied. The article shows that migration streams between SCO member states are rather intensive, and the problem of labor migration becomes more and more urgent. The countries of consuming and supplying of labour force are clearly differentiated in the region. For some countries, labor export is the key sector of economy. At the same time, interstate relations between SCO member states sometimes are rather disputed. The most urgent factors causing the development of migration processes in the region were determined. Among them, thefactor of growing outflows from China isespecially noted. It is noted that migration processes are discussed by SCO member states nowadays in terms of illegal migration and international criminality connected with it. It means that the question of labor migration is a real problem. It is indicated that the creation of a specific joint commission on migration policy affiliated with the Council of Foreign Ministers of SCO member states is the necessary condition of effective interaction in migration questions within the framework of Shanghai Cooperation Organization.

  9. International migration: The state-sovereignty-migration nexus

    Directory of Open Access Journals (Sweden)

    D. Chigudu

    2015-12-01

    Full Text Available Commonly, international human migration is blamed for corroding states sovereignty, especially stemming from policy circles, academic literature and citizens of the host countries. This has attracted the attention of the media highlighting hazards of being a migrant, with some countries viewing migrants as enemies; and, Cuba provides a vivid case. Yet in other countries, migrants are viewed as important contributors to social and economic development, with Mexico, the Dominican Republic and India serving as examples. This article locates migrants in the framework of human rights as guided by international law without prejudice to the demands of state sovereignty, but linking the two in the context of developing international standards. Migration is seen as a feature of human history dating back to primordial time. Nothing appears surprising in the movement of people across borders, defining a migrant through emigration and immigration while giving due respect to the sovereignty of states, both sending and receiving. The article discusses the nexus between migrants and state sovereignty in order to highlight the mutual benefit grounded in international law. It attempts to portray a more positive image of the migrant person in light of the global world, socio-economic development and human rights fundamentals. The main challenge remains that of implementing human rights, which appear to be at the crossroads of individual rights and state sovereignty. The paper reveals how the challenge can be overcome while maintaining the structure of rights and freedoms without infringement on states’ sovereignty. It concludes that migrants remain on the periphery of effective protection from the vagaries of the citizens, partly because the state has a tendency to confine certain rights to its citizenry. States possess discretionary authority to control the ingress of foreign nationals into their territories though sometimes they fail to do that as evidenced

  10. RAPID3? Aptly named!

    Science.gov (United States)

    Berthelot, J-M

    2014-01-01

    The RAPID3 score is the sum of three 0-10 patient self-report scores: pain, functional impairment on MDHAQ, and patient global estimate. It requires 5 seconds for scoring and can be used in all rheumatologic conditions, although it has mostly been used in rheumatoid arthritis where cutoffs for low disease activity (12/30) have been set. A RAPID3 score of ≤ 3/30 with 1 or 0 swollen joints (RAPID3 ≤ 3 + ≤ SJ1) provides remission criteria comparable to Boolean, SDAI, CDAI, and DAS28 remission criteria, in far less time than a formal joint count. RAPID3 performs as well as the DAS28 in separating active drugs from placebos in clinical trials. RAPID3 also predicts subsequent structural disease progression. RAPID3 can be determined at short intervals at home, allowing the determination of the area under the curve of disease activity between two visits and flare detection. However, RAPID3 should not be seen as a substitute for DAS28 and face to face visits in routine care. Monitoring patient status with only self-report information without a rheumatologist's advice (including joints and physical examination, and consideration of imaging and laboratory tests) may indeed be as undesirable for most patients than joint examination without a patient questionnaire. Conversely, combining the RAPID3 and the DAS28 may consist in faster or more sensitive confirmation that a medication is effective. Similarly, better enquiring of most important concerns of patients (pain, functional status and overall opinion on their disorder) should reinforces patients' confidence in their rheumatologist and treatments.

  11. From migration to settlement: the pathways, migration modes and dynamics of neurons in the developing brain

    Science.gov (United States)

    HATANAKA, Yumiko; ZHU, Yan; TORIGOE, Makio; KITA, Yoshiaki; MURAKAMI, Fujio

    2016-01-01

    Neuronal migration is crucial for the construction of the nervous system. To reach their correct destination, migrating neurons choose pathways using physical substrates and chemical cues of either diffusible or non-diffusible nature. Migrating neurons extend a leading and a trailing process. The leading process, which extends in the direction of migration, determines navigation, in particular when a neuron changes its direction of migration. While most neurons simply migrate radially, certain neurons switch their mode of migration between radial and tangential, with the latter allowing migration to destinations far from the neurons’ site of generation. Consequently, neurons with distinct origins are intermingled, which results in intricate neuronal architectures and connectivities and provides an important basis for higher brain function. The trailing process, in contrast, contributes to the late stage of development by turning into the axon, thus contributing to the formation of neuronal circuits. PMID:26755396

  12. Elderly Migration and State Fiscal Policy: Evidence from the 1990 Census Migration Flows

    National Research Council Canada - National Science Library

    Karen Smith Conway; Andrew J. Houtenville

    2001-01-01

    .... This research investigates whether elderly migration is affected by state fiscal policies, paying close attention to how the public sector is represented and using net as well as gross state-to-state migration flows...

  13. Persistent leatherback turtle migrations present opportunities for conservation.

    Science.gov (United States)

    Shillinger, George L; Palacios, Daniel M; Bailey, Helen; Bograd, Steven J; Swithenbank, Alan M; Gaspar, Philippe; Wallace, Bryan P; Spotila, James R; Paladino, Frank V; Piedra, Rotney; Eckert, Scott A; Block, Barbara A

    2008-07-15

    Effective transboundary conservation of highly migratory marine animals requires international management cooperation as well as clear scientific information about habitat use by these species. Populations of leatherback turtles (Dermochelys coriacea) in the eastern Pacific have declined by >90% during the past two decades, primarily due to unsustainable egg harvest and fisheries bycatch mortality. While research and conservation efforts on nesting beaches are ongoing, relatively little is known about this population of leatherbacks' oceanic habitat use and migration pathways. We present the largest multi-year (2004-2005, 2005-2006, and 2007) satellite tracking dataset (12,095 cumulative satellite tracking days) collected for leatherback turtles. Forty-six females were electronically tagged during three field seasons at Playa Grande, Costa Rica, the largest extant nesting colony in the eastern Pacific. After completing nesting, the turtles headed southward, traversing the dynamic equatorial currents with rapid, directed movements. In contrast to the highly varied dispersal patterns seen in many other sea turtle populations, leatherbacks from Playa Grande traveled within a persistent migration corridor from Costa Rica, past the equator, and into the South Pacific Gyre, a vast, low-energy, low-productivity region. We describe the predictable effects of ocean currents on a leatherback migration corridor and characterize long-distance movements by the turtles in the eastern South Pacific. These data from high seas habitats will also elucidate potential areas for mitigating fisheries bycatch interactions. These findings directly inform existing multinational conservation frameworks and provide immediate regions in the migration corridor where conservation can be implemented. We identify high seas locations for focusing future conservation efforts within the leatherback dispersal zone in the South Pacific Gyre.

  14. Persistent leatherback turtle migrations present opportunities for conservation.

    Directory of Open Access Journals (Sweden)

    George L Shillinger

    2008-07-01

    Full Text Available Effective transboundary conservation of highly migratory marine animals requires international management cooperation as well as clear scientific information about habitat use by these species. Populations of leatherback turtles (Dermochelys coriacea in the eastern Pacific have declined by >90% during the past two decades, primarily due to unsustainable egg harvest and fisheries bycatch mortality. While research and conservation efforts on nesting beaches are ongoing, relatively little is known about this population of leatherbacks' oceanic habitat use and migration pathways. We present the largest multi-year (2004-2005, 2005-2006, and 2007 satellite tracking dataset (12,095 cumulative satellite tracking days collected for leatherback turtles. Forty-six females were electronically tagged during three field seasons at Playa Grande, Costa Rica, the largest extant nesting colony in the eastern Pacific. After completing nesting, the turtles headed southward, traversing the dynamic equatorial currents with rapid, directed movements. In contrast to the highly varied dispersal patterns seen in many other sea turtle populations, leatherbacks from Playa Grande traveled within a persistent migration corridor from Costa Rica, past the equator, and into the South Pacific Gyre, a vast, low-energy, low-productivity region. We describe the predictable effects of ocean currents on a leatherback migration corridor and characterize long-distance movements by the turtles in the eastern South Pacific. These data from high seas habitats will also elucidate potential areas for mitigating fisheries bycatch interactions. These findings directly inform existing multinational conservation frameworks and provide immediate regions in the migration corridor where conservation can be implemented. We identify high seas locations for focusing future conservation efforts within the leatherback dispersal zone in the South Pacific Gyre.

  15. Migration of Asteroidal Dust Particles

    Science.gov (United States)

    Ipatov, S. I.; Mather, J. C.; Taylor, P. A.

    2003-08-01

    We numerically investigated the migration of dust particles with initial velocities and positions same as those of the numbered asteroids using the Bulirsh-Stoer method of integration and took into account the gravitational influence of 8 planets, radiation pressure, Poynting-Robertson drag and solar wind drag, for values of the ratio between the radiation pressure force and the gravitational force β equal to 0.01, 0.05, 0.1, 0.25, and 0.4. For silicate particles such values of β correspond to diameters of 40, 9, 4, 1.6, and 1 microns, respectively. For each β >= 0.05 we considered N=500 particles (N=250 for β =0.01). In our runs, planets were considered as material points, but, based on orbital elements obtained with a step of probability of a collision of a particle with a terrestrial planet during the lifetime of the particle. For smaller particles, the ratio of the number of particles that collided with the Sun to the total number of simulated particles and the probability of collisions of particles with the terrestrial planets are smaller. The probability of a collision of a migrating dust particle with the Earth for β =0.01 is greater by a factor of 220 than for β =0.4. The mean time ta during which an asteroidal dust particle had a semi-major axis 'a' in intervals with a fixed width is greater for smaller β (for the same initial number of particles) at a3.5 AU than at 'a' between 1 and 3 AU, and are usually maximum at 'a' about 2.3 AU. For β =0.01 the local maxima of ta corresponding to the 5:6, 6:7, 3:4, and 2:3 resonances with the Earth are greater than the maximum at 2.4 AU. The peaks in distribution of migrating asteroidal dust particles with semi-major axis corresponding to the n/(n+1) resonances with Earth and Venus and the gaps associated with the 1:1 resonances with these planets are more pronounced for larger particles. The spatial density of a simulated dust cloud and its luminosity (as seen from outside) were greater for smaller distance

  16. Introduction: population migration and urbanization in developing countries.

    Science.gov (United States)

    Kojima, R

    1996-12-01

    This introductory article discusses the correlation between migration and rapid urbanization and growth in the largest cities of the developing world. The topics include the characteristics of urbanization, government policies toward population migration, the change in absolute size of the rural population, and the problems of maintaining megacities. Other articles in this special issue are devoted to urbanization patterns in China, South Africa, Iran, Korea and Taiwan as newly industrialized economies (NIEs), informal sectors in the Philippines and Thailand, and low-income settlements in Bogota, Colombia, and India. It is argued that increased urbanization is produced by natural population growth, the expansion of the urban administrative area, and the in-migration from rural areas. A comparison of urbanization rates of countries by per capita gross national product (GNP) reveals that countries with per capita GNP of under US$2000 have urbanization rates of 10-60%. Rates are under 30% in Africa, the Middle East, South Asia, China, and Indonesia. Rapid urbanization appears to follow the economic growth curve. The rate of urbanization in Latin America is high enough to be comparable to urbanization in Europe and the US. Taiwan and Korea have high rates of urbanization that surpass the rate of industrialization. Thailand and Malaysia have low rates of urbanization compared to the size of their per capita GNP. Urbanization rates under 20% occur in countries without economic development. Rates between 20% and 50% occur in countries with or without industrialization. East Asian urbanization is progressing along with industrialization. Africa and the Middle East have urbanization without industrialization. In 1990 there were 20 developing countries and 5 developed countries with populations over 5 million. In 10 of 87 developing countries rural population declined in absolute size. The author identifies and discusses four patterns of urban growth.

  17. Stereotactic core needle breast biopsy marker migration: An analysis of factors contributing to immediate marker migration.

    Science.gov (United States)

    Jain, Ashali; Khalid, Maria; Qureshi, Muhammad M; Georgian-Smith, Dianne; Kaplan, Jonah A; Buch, Karen; Grinstaff, Mark W; Hirsch, Ariel E; Hines, Neely L; Anderson, Stephan W; Gallagher, Katherine M; Bates, David D B; Bloch, B Nicolas

    2017-11-01

    To evaluate breast biopsy marker migration in stereotactic core needle biopsy procedures and identify contributing factors. This retrospective study analyzed 268 stereotactic biopsy markers placed in 263 consecutive patients undergoing stereotactic biopsies using 9G vacuum-assisted devices from August 2010-July 2013. Mammograms were reviewed and factors contributing to marker migration were evaluated. Basic descriptive statistics were calculated and comparisons were performed based on radiographically-confirmed marker migration. Of the 268 placed stereotactic biopsy markers, 35 (13.1%) migrated ≥1 cm from their biopsy cavity. Range: 1-6 cm; mean (± SD): 2.35 ± 1.22 cm. Of the 35 migrated biopsy markers, 9 (25.7%) migrated ≥3.5 cm. Patient age, biopsy pathology, number of cores, and left versus right breast were not associated with migration status (P> 0.10). Global fatty breast density (P= 0.025) and biopsy in the inner region of breast (P = 0.031) were associated with marker migration. Superior biopsy approach (P= 0.025), locally heterogeneous breast density, and t-shaped biopsy markers (P= 0.035) were significant for no marker migration. Multiple factors were found to influence marker migration. An overall migration rate of 13% supports endeavors of research groups actively developing new biopsy marker designs for improved resistance to migration. • Breast biopsy marker migration is documented in 13% of 268 procedures. • Marker migration is affected by physical, biological, and pathological factors. • Breast density, marker shape, needle approach etc. affect migration. • Study demonstrates marker migration prevalence; marker design improvements are needed.

  18. Migration delays caused by anthropogenic barriers: modeling dams, temperature, and success on migrating salmon smolts

    Science.gov (United States)

    Marschall, Elizabeth A.; Mather, Martha E.; Parrish, Donna; Allison, Gary W.; McMenemy, James R.

    2011-01-01

    Disruption to migration is a growing problem for conservation and restoration of animal populations. Anthropogenic barriers along migration paths can delay or prolong migrations, which may result in a mismatch with migration-timing adaptations. To understand the interaction of dams (as barriers along a migration path), seasonally changing environmental conditions, timing of Atlantic salmon (Salmo salar) downstream migration, and ultimate migration success, we used 10 years of river temperature and discharge data as a template upon which we simulated downstream movement of salmon. Atlantic salmon is a cool-water species whose downstream migrating smolts must complete migration before river temperatures become too warm. We found that dams had a local effect on survival as well as a survival effect that was spatially and temporally removed from the encounter with the dam. While smolts are delayed by dams, temperatures downstream can reach lethal or near-lethal temperatures; as a result, the match between completion of migration and the window of appropriate migration conditions can be disrupted. The strength of this spatially and temporally removed effect is at least comparable to the local effects of dams in determining smolt migration success in the presence of dams. We also considered smolts from different tributaries, varying in distance from the river mouth, to assess the potential importance of locally adapted migration timing on the effect of barriers. Migration-initiation temperature affected modeled smolt survival differentially across tributaries, with the success of smolts from upstream tributaries being much more variable across years than that of smolts with a shorter distance to travel. As a whole, these results point to the importance of broadening our spatial and temporal view when managing migrating populations. We must consider not only how many individuals never make it across migration barriers, but also the spatially and temporally removed

  19. Migration delays caused by anthropogenic barriers: Modeling dams, temperature, and success of migrating salmon smolts

    Science.gov (United States)

    Marschall, E.A.; Mather, M. E.; Parrish, D.L.; Allison, G.W.; McMenemy, J.R.

    2011-01-01

    Disruption to migration is a growing problem for conservation and restoration of animal populations. Anthropogenic barriers along migration paths can delay or prolong migrations, which may result in a mismatch with migration-timing adaptations. To understand the interaction of dams (as barriers along a migration path), seasonally changing environmental conditions, timing of Atlantic salmon (Salmo salar) downstream migration, and ultimate migration success, we used 10 years of river temperature and discharge data as a template upon which we simulated downstream movement of salmon. Atlantic salmon is a cool-water species whose downstream migrating smolts must complete migration before river temperatures become too warm. We found that dams had a local effect on survival as well as a survival effect that was spatially and temporally removed from the encounter with the dam. While smolts are delayed by dams, temperatures downstream can reach lethal or near-lethal temperatures;as a result, the match between completion of migration and the window of appropriate migration conditions can be disrupted. The strength of this spatially and temporally removed effect is at least comparable to the local effects of dams in determining smolt migration success in the presence of dams. We also considered smolts from different tributaries, varying in distance from the river mouth, to assess the potential importance of locally adapted migration timing on the effect of barriers. Migration-initiation temperature affected modeled smolt survival differentially across tributaries, with the success of smolts from upstream tributaries being much more variable across years than that of smolts with a shorter distance to travel. As a whole, these results point to the importance of broadening our spatial and temporal view when managing migrating populations. We must consider not only how many individuals never make it across migration barriers, but also the spatially and temporally removed

  20. Pseudo-voluntary migration: the case of internal migration system in former Yugoslavia

    Directory of Open Access Journals (Sweden)

    Damir Josipovič

    2013-12-01

    Full Text Available Migration theory has been dichotomised from several different analytical perspectives. The aim of this article is to view migration movements in a holistic scheme taking into account the geographical factors shaping migration patterns at both the point of origin and destination, rather than on the conceptualizations involving the built-in dualisms. The former Yugoslavia with its myriad of cases shows that migration has to be viewed without biased international or internal lenses. Furthermore, the author argues that the migration movements were instead part of a more or less organized system which tended to create circumstances, possibilities and/or impossibilities to migrate. In this way, instead of classifying migrations as either forced or voluntary, the concept of pseudo-voluntary migration movements was proposed. In changing the perspective in which migrations are view in this, the article draws extensively on the moorings theory developed by Bruce Moon. The author gives an updated framework for individual or small group migration analysis. The latter is supplemented by a set of variables and factors in order to make a further use possible at the level of international or internal migration. The author argues that the internal Yugoslav migration system between 1945 and 1991 should be viewed within a framework of potentially coerced, semi-coerced or ‘pseudo-voluntary migration’.

  1. Recovery Migration after Hurricanes Katrina and Rita: Spatial Concentration and Intensification in the Migration System

    Science.gov (United States)

    Fussell, Elizabeth; DeWaard, Jack

    2015-01-01

    Changes in the human migration systems of Hurricane Katrina- and Rita-affected Gulf of Mexico coastline counties provide an example of how climate change may affect coastal populations. Crude climate change models predict a mass migration of “climate refugees,” but an emerging literature on environmental migration suggests most migration will be short-distance and short-duration within existing migration systems, with implications for the population recovery of disaster-struck places. In this research, we derive a series of hypotheses on recovery migration predicting how the migration system of hurricane-affected coastline counties in the Gulf of Mexico was likely to have changed between the pre-disaster and the recovery periods. We test these hypotheses using data from the Internal Revenue Service on annual county-level migration flows, comparing the recovery period migration system (2007–2009) to the pre-disaster period (1999–2004). By observing county-to-county ties and flows we find that recovery migration was strong, as the migration system of the disaster-affected coastline counties became more spatially concentrated while flows within it intensified and became more urbanized. Our analysis demonstrates how migration systems are likely to be affected by the more intense and frequent storms anticipated by climate change scenarios with implications for the population recovery of disaster-affected places. PMID:26084982

  2. Recovery Migration After Hurricanes Katrina and Rita: Spatial Concentration and Intensification in the Migration System.

    Science.gov (United States)

    Curtis, Katherine J; Fussell, Elizabeth; DeWaard, Jack

    2015-08-01

    Changes in the human migration systems of the Gulf of Mexico coastline counties affected by Hurricanes Katrina and Rita provide an example of how climate change may affect coastal populations. Crude climate change models predict a mass migration of "climate refugees," but an emerging literature on environmental migration suggests that most migration will be short-distance and short-duration within existing migration systems, with implications for the population recovery of disaster-stricken places. In this research, we derive a series of hypotheses on recovery migration predicting how the migration system of hurricane-affected coastline counties in the Gulf of Mexico was likely to have changed between the pre-disaster and the recovery periods. We test these hypotheses using data from the Internal Revenue Service on annual county-level migration flows, comparing the recovery period migration system (2007-2009) with the pre-disaster period (1999-2004). By observing county-to-county ties and flows, we find that recovery migration was strong: the migration system of the disaster-affected coastline counties became more spatially concentrated, while flows within it intensified and became more urbanized. Our analysis demonstrates how migration systems are likely to be affected by the more intense and frequent storms anticipated by climate change scenarios, with implications for the population recovery of disaster-affected places.

  3. [Migration in Austria: 1850-1900. Migration flows within the monarchy and the structure of migration to Vienna].

    Science.gov (United States)

    Fassmann, H

    1986-01-01

    The author surveys migration within the Austrian part of the Austro-Hungarian Empire from 1850 to 1900 using census data. "As a result of the increase in regional mobility during the nineteenth century, clearly defined patterns of migration developed involving movement from the peripheral areas to the center.... In the process of this development, various sub-systems of migration appeared. Of these, migration from one region to another was more important than that within the same region...and Vienna, the Imperial capital, became the center of migration." Migrants are studied by place of origin and distance traveled and by social class and demographic characteristics. Employment, segregation, and the integration of urban migrants are also considered. (SUMMARY IN ENG) excerpt

  4. Network migration of ethnic Germans.

    Science.gov (United States)

    Bauer, T; Zimmermann, K F

    1997-01-01

    "This study has argued that network migration is central to actual migratory movements, which suggests that its determinants should be carefully investigated. The analysis demonstrates that the network behavior of ethnic Germans can be explained, to a large degree, by observable characteristics. Two crucial variables were investigated, namely the connections to friends from the country of origin and the settlement close to relatives and friends. East Europeans, especially from Rumania, are significantly more connected to friends from the same country of origin than are East Germans. These connections strongly decline with duration of residence and presence in rural areas. Older people are more likely to settle close to friends or relatives at the time of immigration. Population density increases, education, length of stay in a reception camp, and per capita government expenditures decrease the likelihood of such a settlement." excerpt

  5. Seismic migration in generalized coordinates

    Science.gov (United States)

    Arias, C.; Duque, L. F.

    2017-06-01

    Reverse time migration (RTM) is a technique widely used nowadays to obtain images of the earth’s sub-surface, using artificially produced seismic waves. This technique has been developed for zones with flat surface and when applied to zones with rugged topography some corrections must be introduced in order to adapt it. This can produce defects in the final image called artifacts. We introduce a simple mathematical map that transforms a scenario with rugged topography into a flat one. The three steps of the RTM can be applied in a way similar to the conventional ones just by changing the Laplacian in the acoustic wave equation for a generalized one. We present a test of this technique using the Canadian foothills SEG velocity model.

  6. Spontaneous intraluminal migration of gossypiboma

    Directory of Open Access Journals (Sweden)

    Sebastian Saji

    2011-01-01

    Full Text Available Retained surgical mops following surgery is an avoidable but serious complication. They are seldom reported because of medicolegal implications but clinicians need to be aware about varied presentations of this entity to avoid unnecessary morbidity. We report a case of a 28-year-old woman who presented with chronic diarrhea and lower abdominal pain due to intraluminal migration of the surgical mop into the sigmoid colon 6 months after myomectomy of the uterus. The possibility of gossypiboma was suggested by the contrast-enhanced CT scan of the abdomen. Flexible sigmoidosocpy showed the remnants of the mop inside the lumen of the sigmoid colon. She underwent laparotomy and removal of the surgical mop and became completely asymptomatic. Though gossypiboma is rare clinicians should keep it in mind in patients who had undergone laparotomy previously.

  7. Innate and adaptive immune responses in migrating spring-run adult chinook salmon, Oncorhynchus tshawytscha

    Science.gov (United States)

    Dolan, Brian P.; Fisher, Kathleen M.; Colvin, Michael E.; Benda, Susan E.; Peterson, James T.; Kent, Michael L.; Schreck, Carl B.

    2016-01-01

    Adult Chinook salmon (Oncorhynchus tshawytscha) migrate from salt water to freshwater streams to spawn. Immune responses in migrating adult salmon are thought to diminish in the run up to spawning, though the exact mechanisms for diminished immune responses remain unknown. Here we examine both adaptive and innate immune responses as well as pathogen burdens in migrating adult Chinook salmon in the Upper Willamette River basin. Messenger RNA transcripts encoding antibody heavy chain molecules slightly diminish as a function of time, but are still present even after fish have successfully spawned. In contrast, the innate anti-bacterial effector proteins present in fish plasma rapidly decrease as spawning approaches. Fish also were examined for the presence and severity of eight different pathogens in different organs. While pathogen burden tended to increase during the migration, no specific pathogen signature was associated with diminished immune responses. Transcript levels of the immunosuppressive cytokines IL-10 and TGF beta were measured and did not change during the migration. These results suggest that loss of immune functions in adult migrating salmon are not due to pathogen infection or cytokine-mediated immune suppression, but is rather part of the life history of Chinook salmon likely induced by diminished energy reserves or hormonal changes which accompany spawning.

  8. Intermittent tremor migrations beneath Guerrero, Mexico, and implications for fault healing within the slow slip zone

    Science.gov (United States)

    Peng, Yajun; Rubin, Allan M.

    2017-01-01

    Slow slip events exhibit significant complexity in slip evolution and variations in recurrence intervals. Behavior that varies systematically with recurrence interval is likely to reflect different extents of fault healing between these events. Here we use high-resolution tremor catalogs beneath Guerrero, Mexico, to investigate the mechanics of slow slip. We observe complex tremor propagation styles, including rapid tremor migrations propagating either along the main tremor front or backward, reminiscent of those in northern Cascadia. We also find many migrations that originate well behind the front and repeatedly occupy the same source region during a tremor episode, similar to those previously reported from Shikoku, Japan. These migrations could be driven by slow slip in the surrounding regions, with recurrence intervals possibly modulated by tides. The propagation speed of these migrations decreases systematically with time since the previous migration over the same source area. Tremor amplitudes seem consistent with changes in the propagation speeds being controlled primarily by changes in the slip speeds. One interpretation is that the high propagation speeds and inferred high slip speeds during the migrations with short recurrence intervals are caused by incomplete healing within the host rock adjacent to the shear zone, which could lead to high permeability and reduced dilatant strengthening of the fault gouge. Similar processes may operate in other slow slip source regions such as Cascadia.

  9. Gender, Migration and Remittances in Ghana

    African Journals Online (AJOL)

    Keywords: Remittance, Migration, Social Capital, Female Migration, Gender Discrimination. Introduction. Remittances represent an enormous transfer of resources from the developed to the developing world and in many cases among countries of the South. This has aroused interest among the international community who ...

  10. Citizenship and migration in Arab Gulf monarchies

    DEFF Research Database (Denmark)

    Sater, J.

    2014-01-01

    In many industrialized countries, the issue of migration has traditionally raised the question of whether migrant groups fully enjoy citizenship rights. Political debates about models of migration emphasize either the values of cultural diversity or the value of integration into 'host' societies,...

  11. The role of 'conservatism' in herring migrations

    NARCIS (Netherlands)

    Corten, A.

    2002-01-01

    Herring (Clupea harengus) migrations tend to remain constant over periods of several years or even decades, despite environmental variation. When a migration pattern is changed, apparently in response to an environmental stimulus, the change in migratory behavior sometimes lasts longer than the

  12. The External Dimension of EU Migration Policy

    Directory of Open Access Journals (Sweden)

    Dorina Gjipali

    2017-01-01

    Defining the conditions of consistency and flexibility to which the Union’s external action can bring the management of migration - a management which will pursue all objectives of the EU’s migration policy in accordance with the its principles, such as solidarity and the protection of fundamental rights - is the focus of this paper.

  13. Migration, Rural Poverty and Community Natural Resource ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Migration, Rural Poverty and Community Natural Resource Management in Cambodia ... grant will allow researchers at the Royal University of Phnom Penh to examine the relationship between labour mobility and distress migration, and natural resource management. ... Les chaînes de valeur comme leviers stratégiques.

  14. DIURNAL VERTICAL MIGRATIONS OF MEIOFAUNA IN AN ...

    African Journals Online (AJOL)

    Diurnal vertical migrations of meiofauna were observed in an estuarine sand flat and these were related primarily to desiccation and temperature. The migrations. which occurred in the top 10 cm of the sediment. had a mean range of 5 cm and were most strongly exhibited by the interstitial flatworms. polychaetes and ...

  15. Parental Migration and Children's Outcomes in Romania

    Science.gov (United States)

    Robila, Mihaela

    2011-01-01

    Although Eastern European migration has increased greatly, the research on its impact on children and families has been limited. In this study I examined the impact of parental economic migration on children psychosocial and academic outcomes in Romania, one of largest Eastern European migrant sending country. Surveys were conducted with 382…

  16. Planning the future's forests with assisted migration

    Science.gov (United States)

    Mary I. Williams; R. Kasten Dumroese

    2014-01-01

    Studies show that changes in climate may exceed plant adaptation and migration. The mismatch in rates between climate change and plant adaptation and migration will pose significant challenges for practitioners that select, grow, and outplant native tree species. Native tree species and populations that are planted today must meet the climatic challenges that they will...

  17. Serotonergic Projections Govern Postnatal Neuroblast Migration

    DEFF Research Database (Denmark)

    García-González, Diego; Khodosevich, Konstantin; Watanabe, Yasuhito

    2017-01-01

    In many vertebrates, postnatally generated neurons often migrate long distances to reach their final destination, where they help shape local circuit activity. Concerted action of extrinsic stimuli is required to regulate long-distance migration. Some migratory principles are evolutionarily conse...

  18. Partial migration in fishes: causes and consequences.

    Science.gov (United States)

    Chapman, B B; Hulthén, K; Brodersen, J; Nilsson, P A; Skov, C; Hansson, L-A; Brönmark, C

    2012-07-01

    Partial migration, where only some individuals from a population migrate, has been widely reported in a diverse range of animals. In this paper, what is known about the causes and consequences of partial migration in fishes is reviewed. Firstly, the ultimate and proximate drivers of partial migration are reflected upon: what ecological factors can shape the evolution of migratory dimorphism? How is partial migration maintained over evolutionary timescales? What proximate mechanisms determine whether an individual is migratory or remains resident? Following this, the consequences of partial migration are considered, in an ecological and evolutionary context, and also in an applied sense. Here it is argued that understanding the concept of partial migration is crucial for fisheries and ecosystem managers, and can provide information for conservation strategies. The review concludes with a reflection on the future opportunities in this field, and the avenues of research that are likely to be fruitful to shed light on the enduring puzzle of partial migration in fishes. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  19. Socio-Economic Determinants of International Migration

    Directory of Open Access Journals (Sweden)

    Yaroslav PRYTULA

    2012-05-01

    Full Text Available Since economic factors cannot fully explain the determinants of bilateral migration, this study explores the social and cultural determinants that influence an individual’s decision to migrate. Values, norms and interests in a given culture, may determine whether an individual’s intention to move translates into actual migration. Work values inherent in different cultures could explain why people move or do not move under the condition of perceived economic advantages of migration. A gravity type migration model is used to incorporate variables related both to economic indicators and work values. It is perhaps the first migration study to use the World Value Survey (WVS and the European Value Survey (EVS. We use 2000 stock bilateral migration dataset collected by the World Bank. Our findings indicate that if more aspects of work are valued in a country, this country sends more migrants. Also we show that countries with higher extrinsic work value orientation tend to send more migrants, while countries with higher intrinsic work value orientation tend to send fewer migrants. Our finding shows that the value of work and the level of job security in a country may significantly change migration decision.

  20. Migration control, documentation, and state transformation

    NARCIS (Netherlands)

    Vigneswaran, D.; Segatti, A.; Landau, L.B.

    2011-01-01

    Examines undocumented migration, one of the main outcomes of the transition from formal labor migration to a mixed system, gauges the long-term impacts of the bureaucratic stasis on governance in South Africa, and explores how an ongoing state of crisis in this policy sphere is shaping the everyday

  1. 66 THE CHALLENGES OF MIGRATION AND TECHNOLOGICAL ...

    African Journals Online (AJOL)

    century Africa. Migration if not properly controlled has a deleterious implication that can drastically hamper African technological drive and advancement. Technological development has its own merits and demerits. Technology simply means the devising of tools to manipulate nature. One of the major problems of migration.

  2. A validatable legacy database migration using ORM

    NARCIS (Netherlands)

    Moes, T.H.; Wijbenga, J.P.; Balsters, H.; Huitema, G.B.

    2012-01-01

    This paper describes a method used in a real-life case of a legacy database migration. The difficulty of the case lies in the fact that the legacy application to be replaced has to remain fully available during the migration process while at the same time data from the old system is to be integrated

  3. Intraperitoneal stone migration during percutaneos nephrolithotomy

    Directory of Open Access Journals (Sweden)

    Akif Diri

    2014-12-01

    Full Text Available Percutaneos nephrolithotomy (PNL is the standard care for renal stones larger than 2 cm. The procedure has some major and minor complications. Renal pelvis laceration and stone migration to the retroperitoneum is one of the rare condition. We report the first case of intraperitoneal stone migration during PNL.

  4. An overview of internal migration in Nepal.

    Science.gov (United States)

    Regmi, A B

    1985-01-01

    A summary of internal migration in Nepal is provided, with attention given to its history since the sixteenth century as well as its volume and patterns as recorded in census data for 1952-1954, 1961, 1971, and 1981. Economic and employment conditions as motivations for migration are considered.

  5. MIGRATION INTENTIONS OF GHANAIAN MEDICAL STUDENTS ...

    African Journals Online (AJOL)

    2014-06-01

    Jun 1, 2014 ... The current wave of international migration of doctors has a longer history to it than can be acknowledged1. It has become even more pronounced as a ..... Whilst several studies have looked at the brain drain in. Africa and the migration of doctors, we found none that specifically attempted to understand the ...

  6. The Global Village: Migration and Education.

    Science.gov (United States)

    Bhavnagri, Navaz Peshotan

    2001-01-01

    Introduces this special issue on migration and education, describing the common underlying organizational framework for articles in this issue. Presents five common content strands regarding global immigration and schooling, including multiple reasons for migration, initial marginalization of immigrant groups, gaining resilience from support…

  7. Extreme swimming: The oceanic migrations of anguillids

    DEFF Research Database (Denmark)

    Righton, David; Aarestrup, Kim; Jellyman, Don

    2013-01-01

    to their natal habitat to spawn. In temperate species, the migrations are extreme, requiring larvae and adults to swim thousands of km before reaching their destination, but the migrations of tropical species (hundreds of km) are still remarkable in comparison with many other fish species. To achieve...

  8. Migration and rural development in the Caribbean.

    Science.gov (United States)

    Momsen, J D

    1986-01-01

    The relationship between migration and agricultural development in the Caribbean is examined. The data, collected by survey, concern the islands of Nevis, Montserrat, and Saint Lucia. The results show that migration is not associated with agricultural innovation or the use of specific technical inputs and that it frequently has a negative impact on agricultural productivity and attitudes toward farming.

  9. Economic integration and labor flows: stage migration in farm labor markets in Mexico and the United States.

    Science.gov (United States)

    Zabin, C; Hughes, S

    1995-01-01

    "This article examines the probable effects of the North American Free Trade Agreement (NAFTA) on migration from Mexico to the United States, disputing the view that expansion of jobs in Mexico could rapidly reduce undocumented migration. To the extent that NAFTA causes Mexican export agriculture to expand, migration to the United States will increase rather than decrease in the short run. Data collected in both California and the Mexican State of Baja California show that indigenous migrants from southern Mexico typically first undertake internal migration, which lowers the costs and risks of U.S. migration. Two features of employment in export agriculture were found to be specially significant in lowering the costs of U.S. migration: first, working in export agriculture exposes migrants to more diverse social networks and information about U.S. migration; second, agro-export employment in northern Mexico provides stable employment, albeit low-wage employment, for some members of the family close to the border (especially women and children) while allowing other members of the family to assume the risks of U.S. migration." excerpt

  10. Pre-spawning migration of adult Pacific lamprey, Entosphenus tridentatus, in the Willamette River, Oregon, U.S.A.

    Science.gov (United States)

    Clemens, Benjamin J.; Mesa, Matthew G.; Magie, Robert J.; Young, Douglas A.; Schreck, Carl B.

    2012-01-01

    We describe the migration distances and timing of the adult Pacific lamprey, Entosphenus tridentatus, in the Willamette River Basin (Oregon, U.S.A.). We conducted aerial surveys to track radio-tagged fish upstream of a major waterfall and hydropower complex en route to spawning areas. We detected 24 out of the 43 fish that passed the waterfall-hydropower complex. Of the detected fish, 17 were detected multiple times. Their maximum migration distance upstream in the mainstem Willamette approximated a normal distribution. The maximum distance migrated upstream did not significantly correlate with total body length (r = −0.186, P = 0.385) or date that the fish passed Willamette Falls (r = −0.118, P = 0.582). Fish migrated primarily during the spring to early summer period before stopping during the summer, when peak river temperatures (≥20°C). However, at least three fish continued to migrate upstream after September. Behavior ranged from relatively slow migration, followed by holding; to rapid migration, followed by slow migration further up in the basin. This study provides a basis for informing more detailed research on Pacific lamprey in the future.

  11. Undocumented migration in response to climate change.

    Science.gov (United States)

    Nawrotzki, Raphael J; Riosmena, Fernando; Hunter, Lori M; Runfola, Daniel M

    In the face of climate change induced economic uncertainty, households may employ migration as an adaptation strategy to diversify their livelihood portfolio through remittances. However, it is unclear whether such climate migration will be documented or undocumented. In this study we combine detailed migration histories with daily temperature and precipitation information for 214 weather stations to investigate whether climate change more strongly impacts undocumented or documented migration from 68 rural Mexican municipalities to the U.S. during the years 1986-1999. We employ two measures of climate change, the warm spell duration index (WSDI) and the precipitation during extremely wet days (R99PTOT). Results from multi-level event-history models demonstrate that climate-related international migration from rural Mexico was predominantly undocumented. We conclude that programs to facilitate climate change adaptation in rural Mexico may be more effective in reducing undocumented border crossings than increased border fortification.

  12. Unusual migration of pulmonary artery catheter

    Directory of Open Access Journals (Sweden)

    Sanjay Kuravinakop

    2007-01-01

    Full Text Available Pulmonary artery catheter is widely used in intensive care. Distal migration of the catheter is a know complication. Diagnosis of such a migration is made by both clinical criteria and radiographs. A 55 year old septic lady was admitted to the intensive care unit. Pulmonary artery catheter introduced for cardiac output monitoring migrated from right lung to left lung. Diagnosis was made following a chest radiograph the following day of insertion with the clinical criteria remaining unaltered. Migration of pulmonary artery catheter can occur not only distally but from one lung to another. Clinical criteria alone cannot rule out migration. Chest radiographs form an important part in monitoring the position of the pulmonary artery catheter.

  13. Neuronal Migration and AUTS2 Syndrome.

    Science.gov (United States)

    Hori, Kei; Hoshino, Mikio

    2017-05-14

    Neuronal migration is one of the pivotal steps to form a functional brain, and disorganization of this process is believed to underlie the pathology of psychiatric disorders including schizophrenia, autism spectrum disorders (ASD) and epilepsy. However, it is not clear how abnormal neuronal migration causes mental dysfunction. Recently, a key gene for various psychiatric diseases, the Autism susceptibility candidate 2 (AUTS2), has been shown to regulate neuronal migration, which gives new insight into understanding this question. Interestingly, the AUTS2 protein has dual functions: Cytoplasmic AUTS2 regulates actin cytoskeleton to control neuronal migration and neurite extension, while nuclear AUTS2 controls transcription of various genes as a component of the polycomb complex 1 (PRC1). In this review, we discuss AUTS2 from the viewpoint of human genetics, molecular function, brain development, and behavior in animal models, focusing on its role in neuronal migration.

  14. LHCb migration from Subversion to Git

    Science.gov (United States)

    Clemencic, M.; Couturier, B.; Closier, J.; Cattaneo, M.

    2017-10-01

    Due to user demand and to support new development workflows based on code review and multiple development streams, LHCb decided to port the source code management from Subversion to Git, using the CERN GitLab hosting service. Although tools exist for this kind of migration, LHCb specificities and development models required careful planning of the migration, development of migration tools, changes to the development model, and redefinition of the release procedures. Moreover we had to support a hybrid situation with some software projects hosted in Git and others still in Subversion, or even branches of one projects hosted in different systems. We present the way we addressed the special LHCb requirements, the technical details of migrating large non standard Subversion repositories, and how we managed to smoothly migrate the software projects following the schedule of each project manager.

  15. Rapid small lot manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Harrigan, R.W.

    1998-05-09

    The direct connection of information, captured in forms such as CAD databases, to the factory floor is enabling a revolution in manufacturing. Rapid response to very dynamic market conditions is becoming the norm rather than the exception. In order to provide economical rapid fabrication of small numbers of variable products, one must design with manufacturing constraints in mind. In addition, flexible manufacturing systems must be programmed automatically to reduce the time for product change over in the factory and eliminate human errors. Sensor based machine control is needed to adapt idealized, model based machine programs to uncontrolled variables such as the condition of raw materials and fabrication tolerances.

  16. Androgen-induced cell migration: role of androgen receptor/filamin A association.

    Directory of Open Access Journals (Sweden)

    Gabriella Castoria

    Full Text Available BACKGROUND: Androgen receptor (AR controls male morphogenesis, gametogenesis and prostate growth as well as development of prostate cancer. These findings support a role for AR in cell migration and invasiveness. However, the molecular mechanism involved in AR-mediated cell migration still remains elusive. METHODOLOGY/PRINCIPAL FINDINGS: Mouse embryo NIH3T3 fibroblasts and highly metastatic human fibrosarcoma HT1080 cells harbor low levels of transcriptionally incompetent AR. We now report that, through extra nuclear action, AR triggers migration of both cell types upon stimulation with physiological concentrations of the androgen R1881. We analyzed the initial events leading to androgen-induced cell migration and observed that challenging NIH3T3 cells with 10 nM R1881 rapidly induces interaction of AR with filamin A (FlnA at cytoskeleton. AR/FlnA complex recruits integrin beta 1, thus activating its dependent cascade. Silencing of AR, FlnA and integrin beta 1 shows that this ternary complex controls focal adhesion kinase (FAK, paxillin and Rac, thereby driving cell migration. FAK-null fibroblasts migrate poorly and Rac inhibition by EHT impairs motility of androgen-treated NIH3T3 cells. Interestingly, FAK and Rac activation by androgens are independent of each other. Findings in human fibrosarcoma HT1080 cells strengthen the role of Rac in androgen signaling. The Rac inhibitor significantly impairs androgen-induced migration in these cells. A mutant AR, deleted of the sequence interacting with FlnA, fails to mediate FAK activation and paxillin tyrosine phosphorylation in androgen-stimulated cells, further reinforcing the role of AR/FlnA interaction in androgen-mediated motility. CONCLUSIONS/SIGNIFICANCE: The present report, for the first time, indicates that the extra nuclear AR/FlnA/integrin beta 1 complex is the key by which androgen activates signaling leading to cell migration. Assembly of this ternary complex may control organ development

  17. Evidence that dorsally mounted satellite transmitters affect migration chronology of Northern Pintails

    Science.gov (United States)

    Hupp, Jerry; Kharitonov, Sergei; Yamaguchi, Noriyuki M.; Ozaki, K.; Flint, Paul L.; Pearce, John M.; Tokita, Ken-ichi; Shimada, Tetsuo; Higuchi, Hiroyoshi

    2015-01-01

    We compared migration movements and chronology between Northern Pintails (Anas acuta) marked with dorsally mounted satellite transmitters and pintails marked only with tarsus rings. During weekly intervals of spring and autumn migration between their wintering area in Japan and nesting areas in Russia, the mean distance that ringed pintails had migrated was up to 1000 km farther than the mean distance radiomarked pintails migrated. Radiomarked pintails were detected at spring migration sites on average 9.9 days (90 % CI 8.0, 11.8) later than ringed pintails that were recovered within 50 km. Although ringed and radiomarked pintails departed from Japan on similar dates, the disparity in detection of radiomarked versus ringed pintails at shared sites increased 7.7 days (90 % CI 5.2, 10.2) for each 1000 km increase in distance from Japan. Thus, pintails marked with satellite transmitters arrived at nesting areas that were 2500 km from Japan on average 19 days later than ringed birds. Radiomarked pintails were detected at autumn migration stopovers on average 13.1 days (90 % CI 9.8, 16.4) later than ringed birds that were recovered within 50 km. We hypothesize that dorsal attachment of 12–20 g satellite transmitters to Northern Pintails increased the energetic cost of flight, which resulted in more rapid depletion of energetic reserves and shortened the distance pintails could fly without refueling. Radiomarked pintails may have used more stopovers or spent longer periods at stopovers. causing their migration schedule to diverge from ringed pintails. We urge further evaluation of the effects of dorsally mounted transmitters on migration chronology of waterfowl.

  18. Inhibition of Rho-associated kinases disturbs the collective cell migration of stratified TE-10 cells

    Directory of Open Access Journals (Sweden)

    Taro Mikami

    2015-01-01

    Full Text Available BACKGROUND: The collective cell migration of stratified epithelial cells is considered to be an important phenomenon in wound healing, development, and cancer invasion; however, little is known about the mechanisms involved. Furthermore, whereas Rho family proteins, including RhoA, play important roles in cell migration, the exact role of Rho-associated coiled coil-containing protein kinases (ROCKs in cell migration is controversial and might be cell-type dependent. Here, we report the development of a novel modified scratch assay that was used to observe the collective cell migration of stratified TE-10 cells derived from a human esophageal cancer specimen. RESULTS: Desmosomes were found between the TE-10 cells and microvilli of the surface of the cell sheet. The leading edge of cells in the cell sheet formed a simple layer and moved forward regularly; these rows were followed by the stratified epithelium. ROCK inhibitors and ROCK small interfering RNAs (siRNAs disturbed not only the collective migration of the leading edge of this cell sheet, but also the stratified layer in the rear. In contrast, RhoA siRNA treatment resulted in more rapid migration of the leading rows and disturbed movement of the stratified portion. CONCLUSIONS: The data presented in this study suggest that ROCKs play an important role in mediating the collective migration of TE-10 cell sheets. In addition, differences between the effects of siRNAs targeting either RhoA or ROCKs suggested that distinct mechanisms regulate the collective cell migration in the simple epithelium of the wound edge versus the stratified layer of the epithelium.

  19. The role of migration-specific and migration-relevant policies in migrant decision-making in transit

    NARCIS (Netherlands)

    Kuschminder - de Guerre, Katie; Koser, Khalid

    2017-01-01

    This paper examines the role of migration-specific and migration-relevant policies in migrant decision-making factors for onwards migration or stay in Greece and Turkey. In this paper we distinguish migration-specific policies from migration-relevant policies in transit and destination countries,

  20. Rapid Cycling and Its Treatment

    Science.gov (United States)

    ... Announcements Public Service Announcements Partnering with DBSA Rapid Cycling and its Treatment What is bipolar disorder? Bipolar ... to Depression and Manic Depression . What is rapid cycling? Rapid cycling is defined as four or more ...

  1. Migration of Interplanetary Dust Particles

    Science.gov (United States)

    Ipatov, S. I.; Mather, J. C.; Guillory, J. U.

    2004-05-01

    We studied the orbital evolution of dust particles under the gravitational influence of planets (excluding Pluto), radiation pressure, Poynting--Robertson drag, and solar wind drag. Initial positions and velocities of considered asteroidal and kuiperoidal particles were the same as those of the discovered main-belt asteroids and trans-Neptunian objects, respectively. We considered cometary particles started from Comet 2P Encke. The values of the ratio β between the radiation pressure force and the gravitational force varied from 0.0004 to 0.4 (for silicates, such values correspond to particle diameters d between 1000 and 1 microns; for water ice, the diameters are greater by a factor of 3 than those for silicates). The mean probabilities P of collisions of asteroidal and cometary dust particles with Earth and Venus during lifetimes of particles were maximum at β ˜0.002-0.004 (i.e., at d ˜100-200 microns for silicate particles). At β ≥0.01 the values of P and the mean times T spent by particles in Earth-crossing and Venus-crossing orbits quickly decrease with an increase of β (usually P∝1/β and T∝1/β ). At β ˜0.0004-0.001 the values of P and T for asteroidal dust particles were smaller than those at β ˜0.002-0.004, though maximum times until collisions of particles with the Sun were greater for smaller β (greater times were needed for larger particles to migrate to the orbits of the terrestrial planets). Cratering records showed that the peak of diameters of dust particles colliding with the Earth was at 200 microns. This is in accordance with our simulations, if the number of particles with diameters greater than D is proportional to D-α , where α ˜2-3. At β ≥0.02 and β ≤0.001 some asteroidal particles (≤4 % at β ≤0.1) migrated beyond Jupiter's orbit. A few asteroidal particles collided with the Sun after moving outside Jupiter's orbit for a long time. The peaks in the distribution of migrating asteroidal dust particles with semi

  2. Rapid manufacturing for microfluidics

    CSIR Research Space (South Africa)

    Land, K

    2012-10-01

    Full Text Available . Microfluidics is at the forefront of developing solutions for drug discovery, diagnostics (from glucose tests to malaria and TB testing) and environmental diagnostics (E-coli monitoring of drinking water). In order to quickly implement new designs, a rapid...

  3. Rapid Prototyping in PVS

    Science.gov (United States)

    Munoz, Cesar A.; Butler, Ricky (Technical Monitor)

    2003-01-01

    PVSio is a conservative extension to the PVS prelude library that provides basic input/output capabilities to the PVS ground evaluator. It supports rapid prototyping in PVS by enhancing the specification language with built-in constructs for string manipulation, floating point arithmetic, and input/output operations.

  4. Rapid Prototyping Reconsidered

    Science.gov (United States)

    Desrosier, James

    2011-01-01

    Continuing educators need additional strategies for developing new programming that can both reduce the time to market and lower the cost of development. Rapid prototyping, a time-compression technique adapted from the high technology industry, represents one such strategy that merits renewed evaluation. Although in higher education rapid…

  5. Migration, pauvreté rurale et gestion communautaire des ressources ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Migration, Rural Poverty and Community Natural Resource Management in Cambodia. Cambodia has a long history of migration, dislocation and forced resettlement. View moreMigration, Rural Poverty and Community Natural Resource Management in Cambodia ...

  6. [Migration in the German Democratic Republic: rural flight and urbanization].

    Science.gov (United States)

    Belwe, K

    1987-05-01

    Patterns of internal migration in the German Democratic Republic since the 1950s are examined. The emphasis is on rural-urban migration. The side effects and later consequences of planned migration are discussed.

  7. Migration and mental health: An interface.

    Science.gov (United States)

    Virupaksha, H G; Kumar, Ashok; Nirmala, Bergai Parthsarathy

    2014-07-01

    Migration is a universal phenomenon, which existed with the subsistence of the human beings on earth. People migrate from one place to another for several reasons, but the goal or main reason behind changing the residence would be improving their living conditions or to escape from debts and poverty. Migration is also a social phenomenon which influences human life and the environment around. Hence, migration has a great impact on any geographical area and it is known as one of the three basic components of population growth of any particular region (the other two are, mortality and fertility). Migration involves certain phases to go through; hence, it is a process. Many times, lack of preparedness, difficulties in adjusting to the new environment, the complexity of the local system, language difficulties, cultural disparities and adverse experiences would cause distress to the migrants. Moreover subsequently it has a negative impact on mental well-being of such population. Due to globalization, modernization, improved technologies and developments in all the sectors, the migration and its impact on human well-being is a contemporary issue; hence, here is an attempt to understand the migration and its impact on the mental health of the migrants based on the studies conducted around.

  8. Mitigation of artifacts in rtm with migration kernel decomposition

    KAUST Repository

    Zhan, Ge

    2012-01-01

    The migration kernel for reverse-time migration (RTM) can be decomposed into four component kernels using Born scattering and migration theory. Each component kernel has a unique physical interpretation and can be interpreted differently. In this paper, we present a generalized diffraction-stack migration approach for reducing RTM artifacts via decomposition of migration kernel. The decomposition leads to an improved understanding of migration artifacts and, therefore, presents us with opportunities for improving the quality of RTM images.

  9. Image migration: measured retrieval rates

    Science.gov (United States)

    Witt, Robert M.

    2007-03-01

    When the Indianapolis Veterans Affairs Medical Center changed Picture Archiving and Communication Systems (PACS) vendors, we chose to use "on demand" image migration as the more cost effective solution. The legacy PACS stores the image data on optical disks in multi-platter jukeboxes. The estimated size of the legacy image data is about 5 terabytes containing studies from ~1997 to ~2003. Both the legacy and the new PACS support a manual DICOM query/retrieve. We implemented workflow rules to determine when to fetch the relevant priors from the legacy PACS. When a patient presents for a new radiology study, we used the following rules to initiate the manual DICOM query/retrieve. For general radiography we retrieved the two most recent prior examinations and for the modalities MR and CT we retrieved the clinically relevant prior examinations. We monitored the number of studies retrieved each week for about a 12 month period. For our facility which performs about 70,000 radiology examinations per year, we observed an essentially constant retrieval rate of slightly less than 50 studies per week. Some explanations for what may be considered an anomalous result maybe related to the fact that we are a tertiary care facility and a teaching hospital.

  10. Phospholipase D is essential for keratocyte-like migration of NBT-II cells.

    Science.gov (United States)

    Nagasaki, Akira; Inotsume, Kimiko; Kanada, Masamitsu; Uyeda, Taro Q P

    2008-01-01

    NBT-II cells on collagen-coated substrates move rapidly and persistently, maintaining a semi-circular shape with a large lamellipodium, in a manner similar to fish keratocytes. The inhibitor of phospholipase D (PLD), n-butanol, completely blocked the migration and disturbed the characteristic localization of actin along the edge of lamellipodia. To investigate the functional difference between the two isozymes of PLD (PLD1 and PLD2), we transfected NBT-II cells with vectors expressing shRNA to deplete PLD1 or PLD2. Depletion of both PLD1 and 2 by RNA interference reduced the velocity of the migration, but depletion of PLD2 inhibited motility more severely than that of PLD1. Furthermore, GFP-PLD2 was localized to the protruding regions of lamellipodia in migrating cells. Thus, PLD is essential for the maintenance of keratocyte-like locomotion of NBT-II cells, presumably by regulating the actin cytoskeleton.

  11. Geophysics. Migrating tremor off southern Kyushu as evidence for slow slip of a shallow subduction interface.

    Science.gov (United States)

    Yamashita, Y; Yakiwara, H; Asano, Y; Shimizu, H; Uchida, K; Hirano, S; Umakoshi, K; Miyamachi, H; Nakamoto, M; Fukui, M; Kamizono, M; Kanehara, H; Yamada, T; Shinohara, M; Obara, K

    2015-05-08

    Detection of shallow slow earthquakes offers insight into the near-trench part of the subduction interface, an important region in the development of great earthquake ruptures and tsunami generation. Ocean-bottom monitoring of offshore seismicity off southern Kyushu, Japan, recorded a complete episode of low-frequency tremor, lasting for 1 month, that was associated with very-low-frequency earthquake (VLFE) activity in the shallow plate interface. The shallow tremor episode exhibited two migration modes reminiscent of deep tremor down-dip of the seismogenic zone in some other subduction zones: a large-scale slower propagation mode and a rapid reversal mode. These similarities in migration properties and the association with VLFEs strongly suggest that both the shallow and deep tremor and VLFE may be triggered by the migration of episodic slow slip events. Copyright © 2015, American Association for the Advancement of Science.

  12. Complete Impulsive Migration of Feeding Jejunostomy Tube and Jejunal Intussusception - Sporadic Complications of a Common Procedure.

    Science.gov (United States)

    Rashid, Khalid; Asif, Mariam

    2016-06-01

    Feeding jejunostomy is one of the most widely used procedures for enteral nutrition. It is associated with several complications which can be grouped into mechanical, metabolic, nutritional, and infectious. Amongst mechanical complications, complete impulsive tube migration is rarely seen. We hereby report the case of a 60-year old woman, with advanced esophageal carcinoma, re-admitted in the ward with blocked and stuck Foley's catheter placed in the jejenum for feeding purpose. Within hours of admission, patient developed rapid peristalsis and catheter completely disappeared in the abdomen. Exploratory laparotomy was performed to retrieve the catheter, which revealed jejunal intussception and erosions. Migration of the feeding tube is infrequent complication; however, complete migration is even rarer and needs urgent intervention.

  13. Local temperature fine-tunes the timing of spring migration in birds

    DEFF Research Database (Denmark)

    Tøttrup, Anders P.; Rainio, Kalle; Coppack, Timothy

    2010-01-01

    Evidence for climate-driven phenological changes is rapidly increasing at all trophic levels. Our current poor knowledge of the detailed control of bird migration from the level of genes and hormonal control to direct physiological and behavioral responses hampers our ability to understand...... and predict consequences of climatic change for migratory birds. In order to better understand migration phenology and adaptation in environmental changes, we here assess the scale at which weather affects timing of spring migration in passerine birds. We use three commonly used proxies of spring...... breeding area. Local temperature was the best single predictor of phenology with the highest explanatory power achieved in combination with NAO. Furthermore, early individuals are more affected by climatic variation compared to individuals on later passage, indicating that climatic change affects subsets...

  14. Interregional migration pattern in Slovakia: efficiency analysis and demographic consequences.

    Science.gov (United States)

    Podolak, P

    1995-01-01

    The patterns of interregional migration within Slovakia from 1970 to 1990 and their consequences for the Slovakian population are analyzed. The author calculates the migration efficiency, or net movement of population relative to total migration, for each administrative district. He concludes that interregional migration has declined both absolutely and as a percentage of total migration, and that a trend toward short-distance migration has become evident. As migration between the north-western and south-eastern part of the country has declined, intraregional rural-urban migration has increased.

  15. Interntional Migration with Heterogeneous Agents: Theory and Evidence

    DEFF Research Database (Denmark)

    Schröder, Philipp J.H.; Brücker, Herbert

    Two puzzling facts of international migration are that only a small share of a sending country's population emigrates and that net migration rates tend to cease over time. This paper addresses these issues in a migration model with heterogeneous agents that features temporary migration....... In equilibrium a positive relation exists between the stock of migrants and the income differential, while the net migration flow becomes zero. Consequently, empirical migration models, estimating net migration flows instead of stocks, may be misspecified. This suspicion appears to be confirmed by our empirical...... investigation of cointegration relationships of flow and stock migration models....

  16. Theoretical foundations of international migration process studies: analysis of key migration theories development

    Directory of Open Access Journals (Sweden)

    Shymanska K.V.

    2017-03-01

    Full Text Available The need for transformation of Ukraine's migration policy based on globalized world development trends and in response to the challenges of European integration transformations causes the need of researching the theoretical and methodological basis of migration studies, and the regulations of existing theories of international migration. The bibliometric analysis of scientific publications on international migration in cites indexes found that the recent researches on these problems acquire interdisciplinary character. It necessitates the transformation of migration study approaches basing on economic, social, institutional theories and concepts synthesis. The article is devoted to the study of theoretical regulations of existing international migration theories in the context of the evolution of scientists’ views on this phenomenon. The author found that the existing theories of international migration should be divided into three categories (microeconomic, macroeconomic, globalizational that contributes to their understanding in the context of implementation possibilities in migrational public administration practice. It allows to determine the theories which should be used for Ukrainian state migration policy constructing and eliminating or reducing the external migration negative effects.

  17. Mexico-United States labor migration flows.

    Science.gov (United States)

    Bustamante, J A

    1997-01-01

    "International migration from Mexico to the United Sates is viewed very differently depending on from which side of the border this phenomenon is observed and evaluated....[It is] imperative to begin a process of ¿demythifying' migration as a necessary and sufficient condition that would allow both countries to come together within the context of bilateral relations and find ways to act jointly to address the impacts of the issue. Such a demythifying effort must begin with scientific research which can help develop a diagnosis of the costs and benefits that labor migration from Mexico to the United States brings to the two countries." excerpt

  18. Migration and Literature

    DEFF Research Database (Denmark)

    Frank, Søren

    We live in an age of migration and more and more authors have migrant backgrounds. Migration and Literature offers a thorough and thought provoking examination of the thematic and formal role of migration in four contemporary and canonized novelists, Günter Grass, Milan Kundera, Salman Rushdie, a......, and Jan Kjærstad. This book examines how these novelists reflect, problematize, and "resolve" the problems set by the migratory world and analyzes how the novels employ discursive strategies which emphasize their migratory and homeless form....

  19. OECD migration, welfare and skill selectivity

    DEFF Research Database (Denmark)

    Pedersen, Peder; Pytlikova, Mariola; Smith, Nina

    of the immigrants have been from poor countries, where the educational level of the population is low. The comprehensive income support schemes, social safety net and a high tax pressure, may play a role in changing the composition of migration flows. This paper presents empirical evidence on immigration flows...... into 27 OECD countries over the period of 12 years, 1989-2000. Using a fixed effects panel data model, we analyze the determinants of the migration flows during the latest decade. We study whether there are significant selectivity effects in international migration flows, i.e. whether the countries...

  20. The Planets Approach to Migration Tools

    DEFF Research Database (Denmark)

    Zierau, Eld; van Wijk, Caroline

    2008-01-01

    This paper discusses the Planets approach to migration tool development. The approach consists of enhancing existing migration tools rather than developing tools from scratch. This pragmatic approach is based on the Planets view of the current situation for migration tools and two claims. The first...... claim is that the market will cover the required tools for commonly used formats. The second claim is that in the long term less tools will be required due to growing use of archiving standard formats. The Planets view on the current situation, the scope of tool development and the claims stated are...

  1. Strong versus Weak Ties in Migration

    OpenAIRE

    Giulietti, Corrado; Wahba, Jackline; Zenou, Yves

    2014-01-01

    This paper studies the role of strong versus weak ties in the rural-to-urban migration decision in China. We first develop a network model that puts forward the different roles of weak and strong ties in helping workers to migrate to the city. We then use a unique longitudinal data that allows us to test our model by focusing on first-time migration. Strong ties are measured by the closest family contact (excluding household members) while weak ties are determined by the fraction of migrants ...

  2. Analyzing migration phenomena with spatial autocorrelation techniques

    Directory of Open Access Journals (Sweden)

    Giuseppe Borruso

    2013-12-01

    Full Text Available In less than one century, Italy has tested a strong intensification of immigration changing from a country originating great migration flows to a country which is the destination of migration flows. The aim of this paper is to examine foreign immigration in Italy distinguishing according to nationality of foreigners. The spatial dimension of migration flows has been analyzed in this paper using Spatial Autocorrelation techniques and more particularly Local Indicators of Spatial Association in order to analyze the highest values of a foreigner group considering the relationship with the surrounding municipalities.

  3. Aboriginal migration and labour market programs.

    Science.gov (United States)

    Taylor, J

    1992-05-01

    "Despite the potential for government employment policies both to encourage and preclude migration among the Aboriginal workforce, little is known about the impacts of such policies. This paper seeks to construct a base line for identifying these impacts by establishing the spatial structure of labour migration among the Aboriginal and Torres Strait Islander population. It makes use of 1986 Census data to describe the volume and pattern of net and gross flows of working-age Aborigines and Islanders through the national settlement system, distinguishing between movements in remote and closely settled parts of the country. Full determination of the links between policy and migration flows awaits comparison with 1991 Census results." excerpt

  4. Migration, development and remittances in rural Mexico.

    Science.gov (United States)

    Rubenstein, H

    1992-06-01

    The argument is that remittances to Mexico from migrants in the US contribute to household prosperity and lessen the balance of payments problem. The purpose of this article is to provide an overview of the incentives and constraints to development and individual economic well-being in rural Mexico. Examination is made of the financial amount of remittances, the use of remittances, the impact on development of remittances, models of migration, and migration historically. The viewpoint is that migration satisfies labor needs in developed countries to the detriment of underdeveloped countries. $2 billion a year are sent by illegal migrants from the US to Mexico. This sum is 4 times the net earning of Mexico's tourist trade. 21.1% of the Mexican population depend in part on money sent from the US. 79% of illegal migrants remitted money to relatives in Jalisco state. 70% of migrant families receive $170/month. In Guadalupe, 73% of families depended on migrant income. In Villa Guerrero, 50% of households depended on migrant income. Migrant income supported 1 out of 5 households in Mexico. Money is usually spent of household subsistence items. Sometimes money is also spent on community religious festivals, marriage ceremonies, and education of children or improved living conditions. Examples are given of money being used for investment in land and livestock. Migration affects community solidarity, and comparative ethic, and the influence on others to migrate. Employment opportunities are not expanded and cottage and community industries are threatened. Land purchases did not result in land improvements. Migration models are deficient. There is a macro/micro dichotomy. The push-and-pull system is not controllable by individual migrants. The migration remittance model is a product of unequal development and a mechanism feeding migration. Mexican migration has occurred since the 1880's; seasonal migration was encouraged. There was coercion to return to Mexico after the

  5. Service Migration Protocol for NFC Links

    DEFF Research Database (Denmark)

    Nickelsen, Anders; Schwefel, Hans-Peter; Martin, Miquel

    2010-01-01

    of use while preserving state. This paper focuses on the scenario of migration between two devices in which the actual migration procedure is executed over near-field communication (NFC) ad-hoc links. The NFC link is interesting as it gives the user the perception of trust and enables service continuity......In future ubiquitous communication environments, users expect to move freely while continuously interacting with the available applications through a variety of devices. Interactive applications will therefore need to support migration, which means to follow users and adapt to the changing context...

  6. EU-India migration and trade linkages

    OpenAIRE

    TUMBE, Chinmay

    2013-01-01

    CARIM-India: Developing a knowledge base for policymaking on India-EU migration This paper reviews the relationship between migration and trade between India and the European Union (EU). It provides an overview of EU-India trade across various dimensions and links it with migration in three specific contexts: (a) The $ 14 billion EU-India diamond trade that represents nearly 15% of total EU-India merchandise trade, and that is attributed to the direct and active role played by Indian immig...

  7. Flexible reaction norms to environmental variables along the migration route and the significance of stopover duration for total speed of migration in a songbird migrant.

    Science.gov (United States)

    Schmaljohann, Heiko; Lisovski, Simeon; Bairlein, Franz

    2017-01-01

    Predicting the consequences of continuing anthropogenic changes in the environment for migratory behaviours such as phenology remains a major challenge. Predictions remain particularly difficult, because our knowledge is based on studies from single-snapshot observations at specific stopover sites along birds' migration routes. However, a general understanding on how birds react to prevailing environmental conditions, e.g. their 'phenotypic reaction norm', throughout the annual cycle and along their entire migration routes is required to fully understand how migratory birds respond to rapid environmental change. Here, we provide direct evidence that northern wheatears (Oenanthe oenanthe) from a breeding population in Alaska adjusted their probability to resume migration as well as the distance covered per night, i.e. travel speed, to large-scale environmental conditions experienced along their 15,000 km migratory route on both northwards and southwards migrations. These adjustments were found to be flexible in space and time. At the beginning of autumn migration, northern wheatears showed high departure probabilities and high travel speeds at low surface air temperatures, while far away from Alaska both traits decreased with increasing air temperatures. In spring, northern wheatears increasingly exploited flow assistance with season, which is likely a behavioural adjustment to speed up migration by increasing the distance travelled per night. Furthermore, the variation in total stopover duration but not in travel speed had a significant effect on the total speed of migration, indicating the prime importance of total stopover duration in the overall phenology of bird migration. Northern wheatears from Alaska provide evidence that the phenotypic reaction norm to a set of environmental conditions cannot be generalized to universal and persistent behavioural reaction pattern across entire migratory pathways. This highlights the importance of full annual-cycle studies

  8. Rapid manufacturing facilitated customisation

    OpenAIRE

    Tuck, Christopher John; Hague, Richard; Ruffo, Massimiliano; Ransley, Michelle; Adams, Paul Russell

    2008-01-01

    Abstract This paper describes the production of body-fitting customised seat profiles utilising the following digital methods: three dimensional laser scanning, reverse engineering and Rapid Manufacturing (RM). The seat profiles have been manufactured in order to influence the comfort characteristics of an existing ejector seat manufactured by Martin Baker Aircraft Ltd. The seat, known as Navy Aircrew Common Ejection Seat (NACES), was originally designed with a generic profile. ...

  9. Rapid Detection of Pathogens

    Energy Technology Data Exchange (ETDEWEB)

    David Perlin

    2005-08-14

    Pathogen identification is a crucial first defense against bioterrorism. A major emphasis of our national biodefense strategy is to establish fast, accurate and sensitive assays for diagnosis of infectious diseases agents. Such assays will ensure early and appropriate treatment of infected patients. Rapid diagnostics can also support infection control measures, which monitor and limit the spread of infectious diseases agents. Many select agents are highly transmissible in the early stages of disease, and it is critical to identify infected patients and limit the risk to the remainder of the population and to stem potential panic in the general population. Nucleic acid-based molecular approaches for identification overcome many of the deficiencies associated with conventional culture methods by exploiting both large- and small-scale genomic differences between organisms. PCR-based amplification of highly conserved ribosomal RNA (rRNA) genes, intergenic sequences, and specific toxin genes is currently the most reliable approach for bacterial, fungal and many viral pathogenic agents. When combined with fluorescence-based oligonucleotide detection systems, this approach provides real-time, quantitative, high fidelity analysis capable of single nucleotide allelic discrimination (4). These probe systems offer rapid turn around time (<2 h) and are suitable for high throughput, automated multiplex operations that are critical for clinical diagnostic laboratories. In this pilot program, we have used molecular beacon technology invented at the Public health Research Institute to develop a new generation of molecular probes to rapidly detect important agents of infectious diseases. We have also developed protocols to rapidly extract nucleic acids from a variety of clinical specimen including and blood and tissue to for detection in the molecular assays. This work represented a cooperative research development program between the Kramer-Tyagi/Perlin labs on probe development

  10. Tiber Personal Rapid Transit

    Directory of Open Access Journals (Sweden)

    Diego Carlo D'agostino

    2011-02-01

    Full Text Available The project “Tiber Personal Rapid Transit” have been presented by the author at the Rome City Vision Competition1 2010, an ideas competition, which challenges architects, engineers, designers, students and creatives individuals to develop visionary urban proposals with the intention of stimulating and supporting the contemporary city, in this case Rome. The Tiber PRT proposal tries to answer the competition questions with the definition of a provocative idea: a Personal Rapid transit System on the Tiber river banks. The project is located in the central section of the Tiber river and aims at the renewal of the river banks with the insertion of a Personal Rapid Transit infrastructure. The project area include the riverbank of Tiber from Rome Transtevere RFI station to Piazza del Popolo, an area where main touristic and leisure attractions are located. The intervention area is actually no used by the city users and residents and constitute itself a strong barrier in the heart of the historic city.

  11. The dynamics of health and return migration.

    Directory of Open Access Journals (Sweden)

    Anita A Davies

    2011-06-01

    Full Text Available The increasing importance and complexity of migration globally also implies a global increase in return migration, and thus an increased interest in the health of returning migrants. The health of returning migrants is impacted by the cumulative exposure to social determinants and risk factors of health during the migration process, during the return movement, and following return. Circular migration often occurs among the diaspora, which can result in the transfer of knowledge and skills that contribute to development, including health system strengthening. Migrants with dual nationality often return to countries with better health services than their country of origin when they are sick and can not get care at home. To maintain and improve the health of returning migrants, multi-sectoral policies at global and national levels should facilitate access to appropriate and equitable health services, social services, and continuity of care across and within borders.

  12. Urbanism, Migration, and Tolerance: A Reassessment.

    Science.gov (United States)

    Wilson, Thomas C.

    1991-01-01

    Urbanism's impact on the personality may be stronger than previously thought. Finds that urban residence has a strong positive effect on tolerance. Migration also promotes tolerance, regardless of the size of the destination community. (DM)

  13. MODELING AVIAN MIGRATION PHENOLOGY: a senior thesis

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Changing global climate could result in temporal changes in phenological events for plant and animal species. Many birds have shifted their migration timing in...

  14. Migration and relationship power among Mexican women.

    Science.gov (United States)

    Parrado, Emilio A; Flippen, Chenoa A; McQuiston, Chris

    2005-05-01

    Our study drew on original data collected in Durham, NC, and four sending communities in Mexico to examine differences in women's relationship power that are associated with migration and residence in the United States. We analyzed the personal, relationship, and social resources that condition the association between migration and women's power and the usefulness of the Relationship Control Scale (RCS) for capturing these effects. We found support for perspectives that emphasize that migration may simultaneously mitigate and reinforce gender inequities. Relative to their nonmigrant peers, Mexican women in the United States average higher emotional consonance with their partners, but lower relationship control and sexual negotiation power. Methodologically, we found that the RCS is internally valid and useful for measuring the impact of resources on women's power. However, the scale appears to combine diverse dimensions of relationship power that were differentially related to migration in our study.

  15. The Migration-Interstate Conflict Nexus

    National Research Council Canada - National Science Library

    Sabastiano Rwengabo

    2014-01-01

    ...’ forced-return mobilisation. Evidence from the 1978-79 Uganda-Tanzania war, and the post-1994 DRC-Rwanda conflict, indicates that given these conditions forced migration strains interstate security relations by arousing...

  16. The dynamics of health and return migration.

    Science.gov (United States)

    Davies, Anita A; Borland, Rosilyne M; Blake, Carolyn; West, Haley E

    2011-06-01

    The increasing importance and complexity of migration globally also implies a global increase in return migration, and thus an increased interest in the health of returning migrants. The health of returning migrants is impacted by the cumulative exposure to social determinants and risk factors of health during the migration process, during the return movement, and following return. Circular migration often occurs among the diaspora, which can result in the transfer of knowledge and skills that contribute to development, including health system strengthening. Migrants with dual nationality often return to countries with better health services than their country of origin when they are sick and can not get care at home. To maintain and improve the health of returning migrants, multi-sectoral policies at global and national levels should facilitate access to appropriate and equitable health services, social services, and continuity of care across and within borders.

  17. Turkey-EU Migration: The Road Ahead

    National Research Council Canada - National Science Library

    Philip Martin

    2012-01-01

    .... Turkey is a net immigration country, and net migration between Turkey and Germany has been negative in recent years, meaning that more German residents move to Turkey than Turkish residents to Germany...

  18. The possibilities of compressed sensing based migration

    KAUST Repository

    Aldawood, Ali

    2013-09-22

    Linearized waveform inversion or Least-square migration helps reduce migration artifacts caused by limited acquisition aperture, coarse sampling of sources and receivers, and low subsurface illumination. However, leastsquare migration, based on L2-norm minimization of the misfit function, tends to produce a smeared (smoothed) depiction of the true subsurface reflectivity. Assuming that the subsurface reflectivity distribution is a sparse signal, we use a compressed-sensing (Basis Pursuit) algorithm to retrieve this sparse distribution from a small number of linear measurements. We applied a compressed-sensing algorithm to image a synthetic fault model using dense and sparse acquisition geometries. Tests on synthetic data demonstrate the ability of compressed-sensing to produce highly resolved migrated images. We, also, studied the robustness of the Basis Pursuit algorithm in the presence of Gaussian random noise.

  19. Determinants of Intra-ASEAN Migration

    National Research Council Canada - National Science Library

    Michele Tuccio

    2017-01-01

    ...) Economic Community in 2015. This paper looks at the determinants of the movement of workers and find three structural factors that will likely drive further intra-ASEAN migration in the coming years...

  20. Mixed migration after the Libyan Revolution

    OpenAIRE

    Samuel Cheung

    2012-01-01

    Irregular and mixed migration is still of great concern in post-revolutionary Libya, made more complex by the securitisation of border control issues and the inherent challenges of an interim government consolidating its authority.

  1. COMMUNITY SERVICES AND OUT-MIGRATION.

    Science.gov (United States)

    Massey, Douglas S; Williams, Nathalie; Axinn, William G; Ghimire, Dirgha J

    2010-06-01

    This paper investigates the relationship between changing community context and out-migration in one of today's poor countries, seeking to document the various mechanisms by which infrastructure affects the migratory behavior. We focus on the expansion of social and physical facilities and services near to rural people's homes, including transportation, new markets, employment, schools, health clinics, and mass media outlets such as movie halls. We draw upon detailed data from Nepal to estimate the hypothesized effects. The direct effects of expanding economic and human capital infrastructure are clearly negative, reducing out-migration. However, increased economic infrastructure is associated with a greater accumulation of human and social capital among respondents and their parents. Through these intervening mechanisms, economic and social infrastructure increased the odds of migrating out. These results reveal the often countervailing nature of short- and long-term effects of economic and social change and the complex pathways influencing migration outcomes.

  2. State Taxes, Tax Exemptions, and Elderly Migration

    National Research Council Canada - National Science Library

    Ali Sina Önder; Herwig Schlunk

    2015-01-01

    .... We show that the elderly prefer to migrate to states with low inheritance taxes, high property taxes, low amounts of federal revenue transfers, low cost of living, and higher average temperatures...

  3. High-Level Dialogue on International Migration

    Directory of Open Access Journals (Sweden)

    UNHCR

    2006-08-01

    Full Text Available UNHCR wishes to bring the following observations andrecommendations to the attention of the High-LevelDialogue (HLD on International Migration and Development,to be held in New York, 14-15 September 2006:

  4. Religiosity and Migration Aspirations among Mexican Youth.

    Science.gov (United States)

    Hoffman, Steven; Marsiglia, Flavio Francisco; Ayers, Stephanie L

    2015-02-01

    International migration has become an important topic of discussion from a policy and humanitarian perspective. Part of the debate includes a renewed interest in understanding the factors that influence decisions about migration to the US among Mexican youth still residing in their country of origin. The purpose of this study was to advance knowledge specifically about internal and external religiosity and their influence on youths' migration aspirations. The data for this study were collected in 2007 from students enrolled in an alternative high school program located in the state of Guanajuato, Mexico. The findings indicated that as external religiosity increases, the desire to work or live in the USA decreases. Furthermore, as internal religiosity increases, the desire to work or live in the USA and plans to migrate increase. The results are interpreted and discussed in light of previous research on religious and cultural norm adherence.

  5. Migration in Deltas: An Integrated Analysis

    Science.gov (United States)

    Nicholls, Robert J.; Hutton, Craig W.; Lazar, Attila; Adger, W. Neil; Allan, Andrew; Arto, Inaki; Vincent, Katharine; Rahman, Munsur; Salehin, Mashfiqus; Sugata, Hazra; Ghosh, Tuhin; Codjoe, Sam; Appeaning-Addo, Kwasi

    2017-04-01

    Deltas and low-lying coastal regions have long been perceived as vulnerable to global sea-level rise, with the potential for mass displacement of exposed populations. The assumption of mass displacement of populations in deltas requires a comprehensive reassessment in the light of present and future migration in deltas, including the potential role of adaptation to influence these decisions. At present, deltas are subject to multiple drivers of environmental change and often have high population densities as they are accessible and productive ecosystems. Climate change, catchment management, subsidence and land cover change drive environmental change across all deltas. Populations in deltas are also highly mobile, with significant urbanization trends and the growth of large cities and mega-cities within or adjacent to deltas across Asia and Africa. Such migration is driven primarily by economic opportunity, yet environmental change in general, and climate change in particular, are likely to play an increasing direct and indirect role in future migration trends. The policy challenges centre on the role of migration within regional adaptation strategies to climate change; the protection of vulnerable populations; and the future of urban settlements within deltas. This paper reviews current knowledge on migration and adaptation to environmental change to discern specific issues pertinent to delta regions. It develops a new integrated methodology to assess present and future migration in deltas using the Volta delta in Ghana, Mahanadi delta in India and Ganges-Brahmaputra-Meghna delta across India and Bangladesh. The integrated method focuses on: biophysical changes and spatial distribution of vulnerability; demographic changes and migration decision-making using multiple methods and data; macro-economic trends and scenarios in the deltas; and the policies and governance structures that constrain and enable adaptation. The analysis is facilitated by a range of

  6. The responses of tropical forest species to global climate change: acclimate, adapt, migrate, or go extinct?

    Directory of Open Access Journals (Sweden)

    Brian Machovina

    2012-06-01

    Full Text Available In the face of ongoing and future climate change, species must acclimate, adapt or shift their geographic distributions (i.e., "migrate" in order to avoid habitat loss and eventual extinction. Perhaps nowhere are the challenges posed by climate change more poignant and daunting than in tropical forests, which harbor the majority of Earth’s species and are facing especially rapid rates of climate change relative to current spatial or temporal variability. Due to the rapid changes in climate predicted for the tropics, coupled with the apparently low capacities of tropical tree species to either acclimate or adapt to sustained changes in environmental conditions, it is believed that the greatest hope for avoiding the loss of biodiversity in tropical forest is species migrations. This is supported by the fact that topical forests responded to historic changes in climate (e.g., post glacial warming through distributional shifts. However, a great deal of uncertainty remains as to if tropical plant and tree species can migrate, and if so, if they can migrate at the rates required to keep pace with accelerating changes in multiple climatic factors in conjunction with ongoing deforestation and other anthropogenic disturbances. In order to resolve this uncertainty, as will be required to predict, and eventually mitigate, the impacts of global climate change on tropical and global biodiversity, more basic data is required on the distributions and ecologies of tens of thousands of plants species in combination with more directed studies and large-scale experimental manipulations.

  7. FACTS Special Issue on Migration and Health

    OpenAIRE

    Schenker, Marc B.; Riden, Heather E.

    2014-01-01

    Migration is a global phenomenon involving hundreds of millions of people, with major social and economic impacts on migrants in their countries of origin and destination and on their communities. In the U.S., California is by far the most affected state by these population movements. The University of California Global Health Institute (UCGHI), Center of Expertise on Migration and Health (COEMH) is devoted to systematically studying the health consequences of global population movements and ...

  8. Multicore Considerations for Legacy Flight Software Migration

    Science.gov (United States)

    Vines, Kenneth; Day, Len

    2013-01-01

    In this paper we will discuss potential benefits and pitfalls when considering a migration from an existing single core code base to a multicore processor implementation. The results of this study present options that should be considered before migrating fault managers, device handlers and tasks with time-constrained requirements to a multicore flight software environment. Possible future multicore test bed demonstrations are also discussed.

  9. Migrations and nutritional status in the sahel.

    Science.gov (United States)

    Autier, P; D'Altilia, J P; Callewaert, B; Tamboura, B; Delamalle, J P; Vercruysse, V

    1989-09-01

    In the Sahel, migration is of considerable importance. It permits the peasants to adjust to variable food conditions. In areas affected by food shortages, cluster sample studies of villages showed that, as the number of recently abandoned houses in a cluster increased, the prevalence of malnutrition decreased, and this linear trend was significant (p nutritional surveillance. The article provides also a brief description of the current migration patterns in the Sahel and underlines the effects droughts have had on them.

  10. Visualizing Human Migration Trhough Space and Time

    Science.gov (United States)

    Zambotti, G.; Guan, W.; Gest, J.

    2015-07-01

    Human migration has been an important activity in human societies since antiquity. Since 1890, approximately three percent of the world's population has lived outside of their country of origin. As globalization intensifies in the modern era, human migration persists even as governments seek to more stringently regulate flows. Understanding this phenomenon, its causes, processes and impacts often starts from measuring and visualizing its spatiotemporal patterns. This study builds a generic online platform for users to interactively visualize human migration through space and time. This entails quickly ingesting human migration data in plain text or tabular format; matching the records with pre-established geographic features such as administrative polygons; symbolizing the migration flow by circular arcs of varying color and weight based on the flow attributes; connecting the centroids of the origin and destination polygons; and allowing the user to select either an origin or a destination feature to display all flows in or out of that feature through time. The method was first developed using ArcGIS Server for world-wide cross-country migration, and later applied to visualizing domestic migration patterns within China between provinces, and between states in the United States, all through multiple years. The technical challenges of this study include simplifying the shapes of features to enhance user interaction, rendering performance and application scalability; enabling the temporal renderers to provide time-based rendering of features and the flow among them; and developing a responsive web design (RWD) application to provide an optimal viewing experience. The platform is available online for the public to use, and the methodology is easily adoptable to visualizing any flow, not only human migration but also the flow of goods, capital, disease, ideology, etc., between multiple origins and destinations across space and time.

  11. [Migration to and from sections of Rotterdam].

    Science.gov (United States)

    Croes, M M; Van Huis, L T

    1997-01-01

    "The number of people that move to, from or within large cities is, in a relative sense, far greater than the corresponding figure for the other parts of the Netherlands. Big city mobility concerns mostly internal migration. The 1995 migration statistics on sections of Rotterdam show dissimilarities between the different sections of the city with respect to composition and intensity of population flows. This article focuses on the differences between two sections of Rotterdam." (SUMMARY IN ENG) excerpt

  12. Migration and Climate Change in Rural Africa

    OpenAIRE

    Cattaneo, Cristina; Massetti, Emanuele

    2015-01-01

    We analyse whether migration is an adaptation that households employ to cope with climate in Ghana and Nigeria. If migration is part of the present adaptation portfolio of households in developing countries, it is reasonable to expect that it will also be an adaptation to future climate change. It is important to stress that we are interested in long-term climatic conditions rather than in short-term weather fluctuations. The data to test these predictions are drawn from two different househo...

  13. Migrasomes: a new organelle of migrating cells.

    Science.gov (United States)

    da Rocha-Azevedo, Bruno; Schmid, Sandra L

    2015-01-01

    Cell migration is a multi-step process that involves the coordinated action of signaling networks, cytoskeletal dynamics and vesicular trafficking, leading to protrusion and adhesion at the leading edge of cells and contraction and detachment at their rear. In a recent paper in Cell Research, Ma et al. describe the biogenesis of a new exosome-like organelle--named migrasomes--that derive from retraction fibers at the rear of migrating cells and their potential roles in inter-cellular signaling.

  14. Introduction: New Research on Migration and Health

    Directory of Open Access Journals (Sweden)

    Wayne A. Cornelius

    2010-10-01

    Full Text Available This special issue on migration and health derives from an interdisciplinary research workshop held on May 13-14, 2010 under the auspices of the Center of Expertise on Migration and Health (COEMH, a component of the University of California’s Global Health Institute (UCGHI. The COEMH Research Training Workshop brought together 20 advanced graduate students and recent postdoctoral fellows from throughout the University of California system to present their recently completed or ongoing, fiel...

  15. Female Migration in Lesotho : Determinants and Opportunities

    OpenAIRE

    Compernolle, Nell; Chakravarty, Shubha; Botea, Ioana

    2018-01-01

    Migration, internal and external, continues to be a dominant livelihood strategy for households in Lesotho, with almost half (43 percent) of households reporting at least one member living away. The past decade has seen a sharp increase in female migration, due to a halt in new hires of Basotho men in South African mines and a concomitant expansion of jobs primarily for women in the export...

  16. Globalising Chinese Migration: New Spaces, New Meanings

    Directory of Open Access Journals (Sweden)

    Pál Nyíri

    2002-04-01

    Full Text Available The paper reviews new trends in international migration from the People’s Republic of China in the last decade, focusing on two aspects: 1 The geographic expansion and merger of formerly distinct translocal migration flows into a global migration system. It includes the opening up of new migration spaces in Eastern Europe and Southeast Asia; increased mobility between destination countries; and increased interchange between different social strata of migrants, from students to illegal workers; 2 A shift in what the social and cultural meaning of migration is to the migrant, to non-migrants, and to elites, which can be described as “upgrading the migrant” (Wang,1998. Various discourses of migration have converged into a highly success-oriented discourse, which reduces the relevance of social background and path of migration. The People’s Republic of China imbues this discourse with tropes of patriotism and development. Concerning the first aspect, the paper problematises the distinction of flows of legal and illegal migrants, students, tourists, and workers, and calls for a holistic approach in studying the configuration of current migration from the PRC. Concerning the second aspect, the paper questions the persistent theory that the PRC as an entity supports emigration, and points out the conflicting interests of various levels and organisations within the state apparatus. At the same time, it recognises that the PRC, like other states, is currently enjoying a honeymoon with state-sanctioned transnationalism, in which migrants are often being more engaged into nation-building and enfranchised as political citizens than are rural non-migrants.

  17. Post-Socialist International Migration: The Case of China-to-South Korea Ethnic Labour Migration

    OpenAIRE

    Kim, Anna Myunghee

    2010-01-01

    This paper examines an atypical south-north labour migration that emerged in the post-socialist international migration system: China-to-South Korea ethnic labour migration. Over the past decade, South Korea has experienced an unprecedented increase in the arrival of foreign labour. The majority of workers come from the People's Republic of China. Based on a contextual multivariate analysis of primary survey data on 525 predominantly undocumented Korean Chinese labour migrants in Seoul, this ...

  18. Epidermal growth-factor-induced transcript isoform variation drives mammary cell migration.

    Directory of Open Access Journals (Sweden)

    Wolfgang J Köstler

    Full Text Available Signal-induced transcript isoform variation (TIV includes alternative promoter usage as well as alternative splicing and alternative polyadenylation of mRNA. To assess the phenotypic relevance of signal-induced TIV, we employed exon arrays and breast epithelial cells, which migrate in response to the epidermal growth factor (EGF. We show that EGF rapidly--within one hour--induces widespread TIV in a significant fraction of the transcriptome. Importantly, TIV characterizes many genes that display no differential expression upon stimulus. In addition, similar EGF-dependent changes are shared by a panel of mammary cell lines. A functional screen, which utilized isoform-specific siRNA oligonucleotides, indicated that several isoforms play essential, non-redundant roles in EGF-induced mammary cell migration. Taken together, our findings highlight the importance of TIV in the rapid evolvement of a phenotypic response to extracellular signals.

  19. Removal of NAPLs from the unsaturated zone using steam: prevention of downward migration by injecting mixtures of steam and air

    DEFF Research Database (Denmark)

    Schmidt, R.; Gudbjerg, Jacob; Sonnenborg, Torben Obel

    2002-01-01

    Steam injection for remediation of porous media contaminated by nonaqueous phase liquids has been shown to be a potentially efficient technology. There is, however, concern that the technique may lead to downward migration of separate phase contaminant. In this work, a modification of the steam...... injection technology is presented, where a mixture of steam and air was injected. In twodimensional experiments with unsaturated porous medium contaminated with nonaqueous phase liquids, it was demonstrated how injection of pure steam lead to severe downward migration. Similar experiments, where steam...... and air were injected simultaneously, resulted in practically no downward migration and still rapid cleanup was achieved. The processes responsible for the prevention of downward migration when injecting steam–air mixtures were analyzed using a nonisothermal multiphase flow and transport model. Hereby...

  20. Integrating meteorology into research on migration.

    Science.gov (United States)

    Shamoun-Baranes, Judy; Bouten, Willem; van Loon, E Emiel

    2010-09-01

    Atmospheric dynamics strongly influence the migration of flying organisms. They affect, among others, the onset, duration and cost of migration, migratory routes, stop-over decisions, and flight speeds en-route. Animals move through a heterogeneous environment and have to react to atmospheric dynamics at different spatial and temporal scales. Integrating meteorology into research on migration is not only challenging but it is also important, especially when trying to understand the variability of the various aspects of migratory behavior observed in nature. In this article, we give an overview of some different modeling approaches and we show how these have been incorporated into migration research. We provide a more detailed description of the development and application of two dynamic, individual-based models, one for waders and one for soaring migrants, as examples of how and why to integrate meteorology into research on migration. We use these models to help understand underlying mechanisms of individual response to atmospheric conditions en-route and to explain emergent patterns. This type of models can be used to study the impact of variability in atmospheric dynamics on migration along a migratory trajectory, between seasons and between years. We conclude by providing some basic guidelines to help researchers towards finding the right modeling approach and the meteorological data needed to integrate meteorology into their own research. © The Author 2010. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved.

  1. Polystyrene cups and containers: styrene migration.

    Science.gov (United States)

    Tawfik, M S; Huyghebaert, A

    1998-07-01

    The level of styrene migration from polystyrene cups was monitored in different food systems including: water, milk (0.5, 1.55 and 3.6% fat), cold beverages (apple juice, orange juice, carbonated water, cola, beer and chocolate drink), hot beverages (tea, coffee, chocolate and soup (0.0, 0.5, 1, 2, and 3.6% fat), take away foods (yogurt, jelly, pudding and ice-cream), as well as aqueous food simulants (3% acetic acid, 15, 50, and 100% ethanol) and olive oil. Styrene migration was found to be strongly dependent upon the fat content and storage temperature. Drinking water gave migration values considerably lower than all of the fatty foods. Ethanol at 15% showed a migration level equivalent to milk or soup containing 3.6% fat. Maximum observed migration for cold or hot beverages and take-away foods was 0.025% of the total styrene in the cup. Food simulants were responsible for higher migration (0.37% in 100% ethanol). A total of 60 food samples (yogurt, rice with milk, fromage, biogardes, and cheese) packed in polystyrene containers were collected from retail markets in Belgium, Germany, and the Netherlands. The level of styrene detected in the foods was always fat dependent.

  2. International migration and new mobility trends

    Directory of Open Access Journals (Sweden)

    Eva Abramuszkinová Pavlíková

    2011-01-01

    Full Text Available World migration community covers 3% of the world population, in Europe it is around 7% and 4% in the Czech Republic. Europe is an important target for migration stimulated by the work offer but also by wars and natural disasters. In Western Europe at the end of the 20th century there were 20 millions of foreign migrants and also probably 3–5 million illegal migrants.Recently, we have faced new trends in international mobility which are different from traditional migration flows. They include mobility of multinational firms employees, mobility of students, pensioners but also mobility of professionals. Specific group under study is foreign migration or mobility of scientists and researchers. There is another phenomena connected with the development of modern technologies which stimulates the mobility in virtual space. Virtual mobility is another form of mobility which is using virtual space for communication, study, work and other aspects of life. The aim of this paper is to introduce the main trends in international migration including the traditional ones but stressing the new types of international mobility. The focus will be on the current situation in the Czech Republic related to migration.

  3. Spring Bird Migration Phenology in Eilat, Israel

    Directory of Open Access Journals (Sweden)

    Reuven Yosef

    2009-12-01

    Full Text Available Analysis of the mean date of first captures and median arrival dates of spring migration for 34 species of birds at Eilat, Israel, revealed that the earlier a species migrates through Eilat, the greater is the inter-annual variation in the total time of its passage. Birds arrive during spring migration in Eilat in four structured and independent waves. The annual fluctuation in the initial arrival dates (initial capture dates and median dates (median date of all captures, not including recaptures, did not depend on the length of the migratory route. This implies that migrants crossing the Sahara desert depart from their winter quarters on different Julian days in different years. We suggest that negative correlations between the median date of the spring migration of early and late migrants depends upon the easterly (Hamsin wind period. Moreover, we believe that the phenology of all birds during spring migration in Eilat is possibly also determined by external factors such as weather conditions on the African continent or global climatic processes in the Northern hemisphere. Orphean Warblers (Sylvia hortensis show a strong positive correlation (rs=-0.502 of initial capture date with calendar years, whereas other species such as Barred Warbler (S. nisoria; rs = -0.391 and Spotted Flycatcher (Muscicapa striata; rs = -0.398 display an insignificant trend. The Dead Sea Sparrow (Passer moabiticus and Red-Backed Shrike (Lanius collurio are positively correlated regarding initial arrival date and medians of spring migration.

  4. Husbands’ Labour Migration and Wives’ Autonomy

    Science.gov (United States)

    Yabiku, Scott T.; Agadjanian, Victor; Sevoyan, Arusyak

    2010-01-01

    Labour migration leads to significant changes in origin areas. The separation of migrants from the family unit, whether it is nuclear or extended, has profound implications for family organization and for individual family members. We examined the relationship between men’s labour migration and the decision-making autonomy of women who stay behind. The data for our analyses came from a 2006 survey of 1680 married women from 56 rural villages in southern Mozambique. We find that both men’s cumulative migration history and current migration status are positively associated with women’s autonomy. The results suggest that the impact of men’s labour migration on women’s autonomy may persist even after the man’s return. Three intervening factors — women’s employment outside the home, lower fertility, and residential independence from extended family members—did not fully mediate the effects of men’s labour migration. This is consistent with a “direct” impact of men’s absence on women’s autonomy. PMID:20865630

  5. Migration aspects of telemedical software architectures.

    Science.gov (United States)

    Cała, Jacek; Czekierda, Łukasz; Zieliński, Krzysztof

    2004-01-01

    Many existing medical systems are good candidates for improvement via incremental migration. Incremental software improvement is, however, much more difficult if the system consists of independent functional modules built with different technologies. The goal of this paper is to present architecture migration aspects of contemporary telemedical systems. The paper discusses two approaches: the Software Architecture Analysis Method, and the Architecture Tradeoff Analysis Method in the context of migration of the medical teleconsultation system Konsul. The system, designed and implemented under KCT activity, is being successfully employed in day-to-day activities at the John Paul II Hospital in Krakow despite many existing drawbacks in its internal architecture. The paper presents the SAAM method of analysis of legacy systems. Two architectures are proposed as a result of this analysis - one based on the migration of the existing architecture, the other built according to the state-of-the-art Service Oriented Architecture. Konsul II, implementing the migration approach, has already been developed whereas Konsul III is in the design phase. The paper concludes with remarks about migration of telemedical systems.

  6. The gravity model of labor migration behavior

    Science.gov (United States)

    Alexandr, Tarasyev; Alexandr, Tarasyev

    2017-07-01

    In this article, we present a dynamic inter-regional model, that is based on the gravity approach to migration and describes in continuous time the labor force dynamics between a number of conjugate regions. Our modification of the gravity migration model allows to explain the migration processes and to display the impact of migration on the regional economic development both for regions of origin and attraction. The application of our model allows to trace the dependency between salaries levels, total workforce, the number of vacancies and the number unemployed people in simulated regions. Due to the gravity component in our model the accuracy of prediction for migration flows is limited by the distance range between analyzed regions, so this model is tested on a number of conjugate neighbor regions. Future studies will be aimed at development of a multi-level dynamic model, which allows to construct a forecast for unemployment and vacancies trends on the first modeling level and to use these identified parameters on the second level for describing dynamic trajectories of migration flows.

  7. Effects of Migration on Women Mental Health

    Directory of Open Access Journals (Sweden)

    Ayla Tuzcu

    2015-03-01

    Full Text Available People leave their habitats and go to different regions of the world due to various reasons, which is defined as migration. One of the most important changes that have been experienced in migration in the last half century is the increase in women's migration. Women are among the risk groups that are affected by the process of migration at most. A particular attention is attracted to the special requirements of women among groups that are obliged to migrate due to the crisis in their countries. Different lifestyles in the migrated social environment, difficult economic and working conditions, language barrier and relevant adaptation problems all negatively affect the mental health of these women. In order to protect and develop the mental health of migrant women from different cultural groups, it is important to approach these groups as primary risk groups and start multi-directional interventions aimed at their areas required. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2015; 7(1: 56-67

  8. Differential ability of exogenous chemotactic agents to disrupt transendothelial migration of flowing neutrophils.

    Science.gov (United States)

    Luu, N T; Rainger, G E; Nash, G B

    2000-06-01

    Neutrophils migrate through endothelium using an ordered sequence of adhesive interactions and activating signals. To investigate the consequences of disruption of this sequence, we characterized adhesion and migration of neutrophils perfused over HUVEC that had been treated with TNF-alpha for 4 h and evaluated changes caused by exogenously added chemotactic agents. When HUVEC were treated with 2 U/ml TNF, flowing neutrophils adhered, with the majority rolling and relatively few migrating through the monolayer. If fMLP, IL-8, zymosan-activated plasma (a source of activated complement factor C5a), epithelial cell-derived neutrophil-activating peptide (ENA-78), or growth-regulating oncogene, GRO-alpha, was perfused over these neutrophils, they stopped rolling and rapidly migrated over the monolayer, but did not penetrate it. When HUVEC were treated with 100 U/ml TNF, the majority of adherent neutrophils transmigrated. If neutrophils were treated with fMLP, IL-8, C5a, ENA-78, or GRO-alpha just before perfusion over this HUVEC, transmigration, but not adhesion, was abolished. However, when platelet-activating factor was used to activate neutrophils, migration through HUVEC treated with 100 U/ml TNF was not impaired, and migration through HUVEC treated with 2 U/ml TNF was actually increased. Transmigration required ligation of CXC chemokine receptor-2 on neutrophils, and differential desensitization of this receptor (e.g., by fMLP but not platelet-activating factor) may explain the pattern of disruption of migration. Thus, transmigration may require presentation of the correct activators in the correct sequence, and inappropriate activation (e.g., by systemic activators) could cause pathological accumulation of neutrophils in the vessel lumen.

  9. Making the cut: Innovative methods for optimizing perfusion-based migration assays.

    Science.gov (United States)

    Holt, Andrew W; Howard, William E; Ables, Elizabeth T; George, Stephanie M; Kukoly, Cindy A; Rabidou, Jake E; Francisco, Jake T; Chukwu, Angel N; Tulis, David A

    2017-03-01

    Application of fluid shear stress to adherent cells dramatically influences their cytoskeletal makeup and differentially regulates their migratory phenotype. Because cytoskeletal rearrangements are necessary for cell motility and migration, preserving these adaptations under in vitro conditions and in the presence of fluid flow are physiologically essential. With this in mind, parallel plate flow chambers and microchannels are often used to conduct in vitro perfusion experiments. However, both of these systems currently lack capacity to accurately study cell migration in the same location where cells were perfused. The most common perfusion/migration assays involve cell perfusion followed by trypsinization which can compromise adaptive cytoskeletal geometry and lead to misleading phenotypic conclusions. The purpose of this study was to quantitatively highlight some limitations commonly found with currently used cell migration approaches and to introduce two new advances which use additive manufacturing (3D printing) or laser capture microdissection (LCM) technology. The residue-free 3D printed insert allows accurate cell seeding within defined areas, increases cell yield for downstream analyses, and more closely resembles the reported levels of fluid shear stress calculated with computational fluid dynamics as compared to other residue-free cell seeding techniques. The LCM approach uses an ultraviolet laser for "touchless technology" to rapidly and accurately introduce a custom-sized wound area in otherwise inaccessible perfusion microchannels. The wound area introduced by LCM elicits comparable migration characteristics compared to traditional pipette tip-induced injuries. When used in perfusion experiments, both of these newly characterized tools were effective in yielding similar results yet without the limitations of the traditional modalities. These innovative methods provide valuable tools for exploring mechanisms of clinically important aspects of cell

  10. Managing Migration: Is border control fundamental to anti-trafficking and anti- smuggling interventions?

    Directory of Open Access Journals (Sweden)

    Rebecca Miller

    2013-09-01

    Full Text Available Over the last several decades, globalisation and a growing concern over security issues, including transnational crime and terrorism, has shaped migration policies and the priorities of states. As migration rose to the top of many government agendas, a rapid tightening and regularisation of borders ensued in an attempt to keep undesirable, high-risk migrants out of potential destination countries. Concomitantly, transnational crimes, such as trafficking in persons and the smuggling of migrants, have been increasingly defined as border security problems. This article examines the extent to which border control is fundamental to anti-trafficking and anti-smuggling interventions, situating the debate within the wider nexus of globalisation and the securitisation of migration. Based upon their work with the United Nations Office on Drugs and Crime (UNODC Regional Centre for Southeast Asia and the Pacific, the authors take the standpoint that given it is the sovereign right of each state to control its border and regulate migration, the human rights of migrants must be considered within this realpolitik. Clearly, though, this claim is highly political and contentious. In the article, we explore some of the tensions and contradictions that have emerged in this debate, and then develop an argument to suggest that it is possible for states to combine managed migration and strict border controls with the protection of human rights in the current context of globalisation.

  11. [Reseau Migrations et Urbanisation en Afrique de l'Ouest (REMUAO): a long and exacting job].

    Science.gov (United States)

    Traore, S

    1999-12-01

    The First Ministerial Conference on Migration and Urbanization in West Africa held in Bamako, Mali, during November 1-5, 1999, marked the end of the first phase of a research program launched in 1993 in Burkina Faso, Ctte d¿Ivoire, Guinea, Mali, Mauritania, Niger, Nigeria, and Senegal, organized under the Western Africa Migration and Urbanization Network (REMUAO). Created in 1989 with the financial support of the Research Center for International Development (CRDI), REMUAO is the result of the will of a number of African researchers and Africanists to provide the subregion with pertinent data on relevant phenomena. REMUAO was established through the combination of the following factors: the rarity of migration and urbanization data while Africa countries are experiencing considerable human migration and rapid urbanization; concern over the multidisciplinary research approach in social sciences, especially in the field of demography; and concern over how to address questions of international migration. Data collection activities began only 5 years after REMUAO was created. The data collection process is described. As REMUAO network coordinator, CERPOD gained valuable experience that will allow the organization to strengthen its role as an implementing agency in the subregion.

  12. Unrestricted migration favours virulent pathogens in experimental metapopulations: evolutionary genetics of a rapacious life history

    Science.gov (United States)

    Eshelman, Christal M.; Vouk, Roxanne; Stewart, Jodi L.; Halsne, Elizabeth; Lindsey, Haley A.; Schneider, Stacy; Gualu, Miliyard; Dean, Antony M.; Kerr, Benjamin

    2010-01-01

    Understanding pathogen infectivity and virulence requires combining insights from epidemiology, ecology, evolution and genetics. Although theoretical work in these fields has identified population structure as important for pathogen life-history evolution, experimental tests are scarce. Here, we explore the impact of population structure on life-history evolution in phage T4, a viral pathogen of Escherichia coli. The host–pathogen system is propagated as a metapopulation in which migration between subpopulations is either spatially restricted or unrestricted. Restricted migration favours pathogens with low infectivity and low virulence. Unrestricted migration favours pathogens that enter and exit their hosts quickly, although they are less productive owing to rapid extirpation of the host population. The rise of such ‘rapacious’ phage produces a ‘tragedy of the commons’, in which better competitors lower productivity. We have now identified a genetic basis for a rapacious life history. Mutations at a single locus (rI) cause increased virulence and are sufficient to account for a negative relationship between phage competitive ability and productivity. A higher frequency of rI mutants under unrestricted migration signifies the evolution of rapaciousness in this treatment. Conversely, spatially restricted migration favours a more ‘prudent’ pathogen strategy, in which the tragedy of the commons is averted. As our results illustrate, profound epidemiological and ecological consequences of life-history evolution in a pathogen can have a simple genetic cause. PMID:20643740

  13. Cell migration is another player of the minute virus of mice infection

    Energy Technology Data Exchange (ETDEWEB)

    Garcin, Pierre O.; Panté, Nelly, E-mail: pante@zoology.ubc.ca

    2014-11-15

    The parvovirus minute virus of mice, prototype strain (MVMp), preferentially infects and kills cancer cells. This intrinsic MVMp oncotropism may depend in part on the early stages of MVMp infection. To test this hypothesis, we investigated the early events of MVMp infection in mouse LA9 fibroblasts and a highly invasive mouse mammary tumor cell line derived from polyomavirus middle T antigen-mediated transformation. Using a combination of fluorescence and electron microscopy, we found that various parameters of the cell migration process affect MVMp infection. We show that, after binding to the plasma membrane, MVMp particles rapidly cluster at the leading edge of migrating cells, which exhibit higher levels of MVMp uptake than non-motile cells. Moreover, promoting cell migration on a fibronectin matrix increased MVMp infection, and induction of epithelial–mesenchymal transition allowed MVMp replication in non-permissive epithelial cells. Hence, we propose that cell migration influences the early stages of MVMp infection. - Highlights: • We document early steps of MVMp infection. • We report that a fibronectin matrix promotes MVMp infection. • We show that cellular migration plays a role in MVMp uptake. • We show that epithelial–mesenchymal transition allows MVMp replication.

  14. Migration of the Fungal Protein Cryptogein within Tobacco Plants 1

    Science.gov (United States)

    Devergne, Jean-Claude; Bonnet, Philippe; Panabières, Frank; Blein, Jean-Pierre; Ricci, Pierre

    1992-01-01

    Cryptogein (CRY), a protein secreted by Phytophthora cryptogea, causes necrosis on tobacco (Nicotiana tabacum) plants at the site of application (the stem or the roots) and also on distant leaves. Autoradiography of plantlets after root absorption of radioiodinated CRY demonstrated a rapid migration of the label to the leaf lamina via the veins. Using an anti-CRY antiserum, a CRY-related antigen was detected in the stem and leaves of CRY-treated plants at a distance from the site of application. This antigen had the same molecular weight as CRY and was detected in the leaves as early as 1 hour after stem treatment, i.e. long before necrosis was detectable. The antigen was also detected in plants inoculated with P. cryptogea. The distant location of the necrosis induced by the fungus or by CRY can be ascribed to the migration of this protein, which is toxic to tobacco cells. It is proposed that CRY, which also elicits defense reactions in tobacco, might contribute to the hypersensitive response of tobacco to P. cryptogea. ImagesFigure 1Figure 2Figure 4 PMID:16669010

  15. Migration, Occupational Mobility, and Regional Escalators in Scotland

    Directory of Open Access Journals (Sweden)

    Maarten van Ham

    2012-01-01

    Full Text Available This paper seeks to unpick the complex relationship between an individual’s migration behaviour, their place of residence, and their occupational performance in the Scottish labour market between 1991 and 2001. We investigate whether Edinburgh has emerged as an occupational escalator region and whether individuals moving there experience more rapid upward occupational mobility than those living and moving elsewhere. Using country of birth, we also control for an individual’s propensity to make long distance moves during earlier periods of their life course. Using data from the Scottish Longitudinal Study, linking 1991 and 2001 individual census records, and logistic regressions, we show that those who migrate over long distances within or to Scotland are most likely to achieve upward occupational mobility. We also found that Edinburgh is by far the most important regional escalator in Scotland; those moving to Edinburgh are the most likely to experience upward occupational mobility from low to high occupational status jobs. This is an important finding as most of the literature on escalator regions focuses on international mega cities.

  16. Postnatal neurogenesis: from neuroblast migration to neuronal integration.

    Science.gov (United States)

    Belvindrah, Richard; Lazarini, Françoise; Lledo, Pierre-Marie

    2009-01-01

    Ongoing neurogenesis maintains neuronal replacement in a few regions of the mammalian adult brain. One of these regions, the subventricular zone, generates olfactory bulb interneuron precursors that must migrate through the rostral migratory stream to reach the olfactory bulb circuit. There, they rapidly initiate dendritic growth and establish dendro-dendritic contacts with mitral/tufted cells and potentially other local interneurons. The sequential steps involved in neuroblast maturation during development have been studied extensively over previous years. However, the mechanisms and regulatory factors controlling the recruitment and first steps of synaptic integration of newly-formed neurons in the adult forebrain have only recently started to be elucidated. This review provides an integrated view of our current understanding of fate-choice decision in progenitors, how newborn neurons correctly migrate to specific circuits, how they integrate in olfactory bulb microcircuits, and the function they have to fulfill once they survive. The elucidation of these mechanisms may be crucial to understand the functional role of adult neurogenesis and eventually develop therapeutic strategies aimed at re-routing neuroblasts to altered circuits.

  17. Environmental neglect that fuels migration. Regional report 3: Mexico.

    Science.gov (United States)

    1994-01-01

    This article reports the impact of environmental neglect on the Mexican population. Despite its participation in the Organization for Economic Cooperation and Development, Mexico is experiencing an environmental crisis. Being the first developing country to engage in the Green Revolution during the 1950s, the country experienced a four-fold increase in grain production. The population increased rapidly from 27 million to 92 million in the 1990s. Due to the increase in population and because the government was too preoccupied with its economic endeavors, the environment suffered, which in a way counteracted the benefits of the Green Revolution. Furthermore, environmental degradation (like loss of forests, less water supply to agricultural lands) had a chain effect. Large farmers engaging in capital-intensive cash cropping for export are buying out small farmers, which leads to many landless or near-landless peasants. Also, many marginalized farmers have long been forced to migrate into marginal lands. Because of the increase in migration in addition to the present population of 92 million, Mexico is showing inadequacy in securing food, employment, and houses. A realistic prognosis is that many Mexicans in the year 2000 could be poorer than they were in 1985; but with the help of the NAFTA free-trade zone, Mexico is hopeful to increase its employment opportunities and reverse its present situation.

  18. [Biological and social aspects of migration of the Andes population].

    Science.gov (United States)

    Baker, P T

    1977-01-01

    The effect of migration on the biology of human populations is almost unknown. While some studies of populations moving from areas which are poor and without medical care clearly show that movement into more prosperous areas improves general health, these studies fail to show the specific effects of changing physical environments. In the present study migrants from the altiplano of Southern Peru to the adjacent low altitude zones were examined. The data were compared to similar data on migrants from low altitude areas and native low altitude people. Preliminary analysis of the information collected suggested the following: 1. Adult women increase slightly their completed fertility when they move from high to low altitude. Child spacing is particularly decreased but birth sex ratios are not affected. 2. Highland migrants at low altitude produce larger newborns than they do at high altitude and these infants grow more rapidly than high altitude infants. 3. Migrants from high to low altitude suffer more respiratory symptoms than low altitude migrants or lowland natives. 4. Although highland migrants quickly adopt low altitude life styles and diets they do not show the age increases in blood pressure or high levels of serum cholesterol common in lowland natives. On the basis of these findings it is concluded that migration may have some detrimental effects on human health and physical fitness. However, more importantly they show that the specific physical environment in which an individual develops has a significant effect on the health fitness of a migrant to a new environment.

  19. Macrophage Migration and Its Regulation by CSF-1

    Directory of Open Access Journals (Sweden)

    Fiona J. Pixley

    2012-01-01

    Full Text Available Macrophages are terminally differentiated cells of the mononuclear phagocytic lineage and develop under the stimulus of their primary growth and differentiation factor, CSF-1. Although they differentiate into heterogeneous populations, depending upon their tissue of residence, motility is an important aspect of their function. To facilitate their migration through tissues, macrophages express a unique range of adhesion and cytoskeletal proteins. Notably, macrophages do not form large, stable adhesions or actin stress fibers but rely on small, short lived point contacts, focal complexes and podosomes for traction. Thus, macrophages are built to respond rapidly to migratory stimuli. As well as triggering growth and differentiation, CSF-1 is also a chemokine that regulates macrophage migration via activation the CSF-1 receptor tyrosine kinase. CSF-1R autophosphorylation of several intracellular tyrosine residues leads to association and activation of many downstream signaling molecules. However, phosphorylation of just one residue, Y721, mediates association of PI3K with the receptor to activate the major motility signaling pathways in macrophages. Dissection of these pathways will identify drug targets for the inhibition of diseases in which macrophages contribute to adverse outcomes.

  20. EMPIRICAL REFLECTIONS ON MIGRATION PHENOMENON. MAJOR EFFECTS OF MIGRATION ON THE HUMAN CAPITAL

    Directory of Open Access Journals (Sweden)

    Simona BUTA

    2013-12-01

    Full Text Available The paper Empirical reflections on migration phenomenon. Major effects of migration on the human capital analyzes the migration flows of the workforce (as part of the human capital globally/regionally, especially the highly qualified workforce migration. The qualified manpower processes of attracting on the work market have not been always well understood and, in some cases, have generated a series of difficulties. This is the reason why we will focus on the „waste of brains” phenomenon, which appears when highly qualified individuals are neither employed in the source-country nor in the target country; and, if they are, their job is below their qualifications.

  1. The Russian Brides in Antalya: From Migration to Marriage, from Marriage to Migration

    OpenAIRE

    Deniz, Ayla; Özgür, E. Murat

    2014-01-01

    Marriage is a major cause of migration from Russia to Turkey, and particularly to the tourism city of Antalya. These marriage migrations increase the number and visibility of Russian migrants, which leads to significant changes in social life. The main motivation for this study is to understand the mechanism of marriage migration between Russian women and Turkish men. It examines the migration and settlement processes of Russian women who have settled in the tourism city of Antalya through in...

  2. Migration and risk: net migration in marginal ecosystems and hazardous areas

    Science.gov (United States)

    de Sherbinin, Alex; Levy, Marc; Adamo, Susana; MacManus, Kytt; Yetman, Greg; Mara, Valentina; Razafindrazay, Liana; Goodrich, Benjamin; Srebotnjak, Tanja; Aichele, Cody; Pistolesi, Linda

    2012-12-01

    The potential for altered ecosystems and extreme weather events in the context of climate change has raised questions concerning the role that migration plays in either increasing or reducing risks to society. Using modeled data on net migration over three decades from 1970 to 2000, we identify sensitive ecosystems and regions at high risk of climate hazards that have seen high levels of net in-migration and out-migration over the time period. This paper provides a literature review on migration related to ecosystems, briefly describes the methodology used to develop the estimates of net migration, then uses those data to describe the patterns of net migration for various ecosystems and high risk regions. The study finds that negative net migration generally occurs over large areas, reflecting its largely rural character, whereas areas of positive net migration are typically smaller, reflecting its largely urban character. The countries with largest population such as China and India tend to drive global results for all the ecosystems found in those countries. Results suggest that from 1970 to 2000, migrants in developing countries have tended to move out of marginal dryland and mountain ecosystems and out of drought-prone areas, and have moved towards coastal ecosystems and areas that are prone to floods and cyclones. For North America results are reversed for dryland and mountain ecosystems, which saw large net influxes of population in the period of record. Uncertainties and potential sources of error in these estimates are addressed.

  3. Migration et sexospécificités : le point de vue du mouvement ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les mouvements de femmes en Inde ont du mal à résoudre les problèmes suscités par les changements rapides au chapitre des relations sociales et les vulnérabilités reliées, entre autres, au phénomène de la migration. Ce projet permettra à une ... Les chaînes de valeur comme leviers stratégiques. Les entreprises ...

  4. An overview of some concepts, potentials, issues, and realities of assisted migration for climate change adaptation in forests

    Science.gov (United States)

    Louis R. Iverson; Matthew P. Peters; Stephen Matthews; Anantha. Prasad

    2013-01-01

    The climate has always been changing, but the rapid rate of climate change, as projected by the IPCC (2007) will likely place unique stresses on plant communities. In addition, anthropogenic barriers (e.g., fragmented land use) present a significant modern constraint that will limit the ability of species migration in responses to a changing climate. As such, managers...

  5. Rapidly variable relatvistic absorption

    Science.gov (United States)

    Parker, M.; Pinto, C.; Fabian, A.; Lohfink, A.; Buisson, D.; Alston, W.; Jiang, J.

    2017-10-01

    I will present results from the 1.5Ms XMM-Newton observing campaign on the most X-ray variable AGN, IRAS 13224-3809. We find a series of nine absorption lines with a velocity of 0.24c from an ultra-fast outflow. For the first time, we are able to see extremely rapid variability of the UFO features, and can link this to the X-ray variability from the inner accretion disk. We find a clear flux dependence of the outflow features, suggesting that the wind is ionized by increasing X-ray emission.

  6. Rapid prototype and test

    Energy Technology Data Exchange (ETDEWEB)

    Gregory, D.L.; Hansche, B.D.

    1996-06-01

    In order to support advanced manufacturing, Sandia has acquired the capability to produce plastic prototypes using stereolithography. Currently, these prototypes are used mainly to verify part geometry and ``fit and form`` checks. This project investigates methods for rapidly testing these plastic prototypes, and inferring from prototype test data actual metal part performance and behavior. Performances examined include static load/stress response, and structural dynamic (modal) and vibration behavior. The integration of advanced non-contacting measurement techniques including scanning laser velocimetry, laser holography, and thermoelasticity into testing of these prototypes is described. Photoelastic properties of the epoxy prototypes to reveal full field stress/strain fields are also explored.

  7. Right-Rapid-Rough

    Science.gov (United States)

    Lawrence, Craig

    2003-01-01

    IDEO (pronounced 'eye-dee-oh') is an international design, engineering, and innovation firm that has developed thousands of products and services for clients across a wide range of industries. Its process and culture attracted the attention of academics, businesses, and journalists around the world, and are the subject of a bestselling book, The Art of Innovation by Tom Kelley. One of the keys to IDEO's success is its use of prototyping as a tool for rapid innovation. This story covers some of IDEO's projects, and gives reasons for why they were successful.

  8. Active pelagic migrations of the bivalve Macoma balthica are dangerous

    NARCIS (Netherlands)

    Hiddink, J.G.; Kock, R.P; Wolff, W.J.

    2002-01-01

    The bivalve Macoma balthica migrates twice during the benthic part of its life cycle. During the spring migration (May-June), the newly settled spat (0-group) migrates to the nurseries in the high intertidal. Seven to nine months later, the bivalves migrate back to the low tidal flats and the

  9. The influence of migration speed on cooperation in spatial games

    Science.gov (United States)

    Li, Wen-Jing; Jiang, Luo-Luo; Gu, Changgui; Yang, Huijie

    2017-12-01

    Migration is a common phenomenon in human society which provides a person an opportunity to search for a new life from one area to another. In the framework of game theory, people may migrate to escape from a current adverse environment (evading defection). Since people may migrate at different speeds, it is interesting to figure out the influence of migration speed on the evolution of cooperative behavior. In an attempt to discover the influence, we propose here a model based on an adaptive migration mechanism. In this model, an individual migrates or updates his/her strategy asynchronously, which is tuned by migration frequency. Firstly, it is found that an appropriate migration speed may evoke an effective mechanism, which enables cooperators dominate even in highly adverse conditions. Secondly, we check how migration speed alters the paradigm of cooperation quantitatively in the conditions of different migration frequency. When migration frequency is high, cooperation is promoted only at a small migration speed. However, when migration frequency is low, cooperation is always promoted at any migration speed. In addition, we also investigated the influence of temptation to defect on cooperation for the case of different migration speeds and migration frequencies. Our results may provide a fresh perspective on the understanding of how human behavior affects cooperation.

  10. Walls Won’t Work : International law for sustainable migration

    NARCIS (Netherlands)

    Brus, Marcel

    2016-01-01

    In this essay I argue that to find sustainable solutions for handling international migration it is necessary to develop fundamental international principles on migration as a basis for global governance and international law. The essay briefly discusses general aspects of migration and migration

  11. Review of: Islam, Migration and Integration: The Age of Securitization

    DEFF Research Database (Denmark)

    Vinding, Niels Valdemar

    2010-01-01

    Islam, Migration and Integration: The Age of Securitization. By Ayhan Kaya. (Migration, Minorities and Citizenship). Houndmills, Basingstoke: Palgrave Macmillan, 2009. Pp. xiv+249. Hbk 978-0-230-51679-3. £55.......Islam, Migration and Integration: The Age of Securitization. By Ayhan Kaya. (Migration, Minorities and Citizenship). Houndmills, Basingstoke: Palgrave Macmillan, 2009. Pp. xiv+249. Hbk 978-0-230-51679-3. £55....

  12. Conceptualising Irish rural youth migration: a biographical approach.

    Science.gov (United States)

    Ni Laoire, C

    2000-01-01

    This paper explores the usefulness of a biographical approach in studying Irish rural youth migration. There have been calls recently for an approach to migration study that involves conceptualizing migration as part of individual biographies as well as social structures. However, there is little research that explicitly adopts a biographical approach. This paper presents the theoretical underpinnings, methodological issues and findings of a recent study that was guided by the principles of a biographical approach to migration. The study was an exploration of life-path formation among Irish rural youth from the 1970s to the 1990s. The paper focuses on the three key elements of a biographical approach to migration, and relates them to Irish rural youth migration. Firstly, migration is considered as part of an individual's biography, and the methodological implications of this are explored. Secondly, it is argued, drawing on the research in Ireland, that migration decision-making is a multilayered process. In the case of Irish rural youth migration, a biographical approach highlights the complexity of migration decision-making, revealing the tensions and struggles that lie behind each move, and thus raises questions over the tendency towards simplification of the migration process. Finally, it is argued that migration is a cultural phenomenon, but that this assertion needs careful qualification. This paper problematizes the role of culture in migration processes by untangling the systems of competing discourses of migration that underlie societal norms regarding migration, thereby challenging the view of migration as "normal" for particular societies or cultures.

  13. Social Dynamics of Return Migration to Puerto Rico.

    Science.gov (United States)

    de Cintron, Celia Fernandez; Vales, Pedro A.

    The sociological elements associated with the process of return migration such as the motivations responsible for, or associated not only with return migration but with the migration process in general, are addressed in this investigation. Among the questions that guide the research problem are the following: the meaning of migration and of return…

  14. urban migration dynamics in Rwanda 1960 to 2010

    African Journals Online (AJOL)

    cntaganda

    Diagram 2: Migration as an economic decision. Diagram 3. Harris Todaro Model of migration. Source: Derek Byerlee(1974) Rural urban migration in Africa: Theory, policy and research implications. International Migration Review adopted from Todaro 9th Edition pg 341. 1. Complementary factors e.g land. 2. Govt policies. 3.

  15. Partial diel migration: A facultative migration underpinned by long-term inter-individual variation.

    Science.gov (United States)

    Harrison, Philip M; Gutowsky, Lee F G; Martins, Eduardo G; Patterson, David A; Cooke, Steven J; Power, Michael

    2017-09-01

    The variations in migration that comprise partial diel migrations, putatively occur entirely as a consequence of behavioural flexibility. However, seasonal partial migrations are increasingly recognised to be mediated by a combination of reversible plasticity in response to environmental variation and individual variation due to genetic and environmental effects. Here, we test the hypothesis that while partial diel migration heterogeneity occurs primarily due to short-term within-individual flexibility in behaviour, long-term individual differences in migratory behaviour also underpin this migration variation. Specifically, we use a hierarchical behavioural reaction norm approach to partition within- and among-individual variation in depth use and diel plasticity in depth use, across short- and long-term time-scales, in a group of 47 burbot (Lota lota) tagged with depth-sensing acoustic telemetry transmitters. We found that within-individual variation at the among-dates-within-seasons and among-seasons scale, explained the dominant proportion of phenotypic variation. However, individuals also repeatedly differed in their expression of migration behaviour over the 2 year study duration. These results reveal that diel migration variation occurs primarily due to short-term within-individual flexibility in depth use and diel migration behaviour. However, repeatable individual differences also played a key role in mediating partial diel migration. These findings represent a significant advancement of our understanding of the mechanisms generating the important, yet poorly understood phenomena of partial diel migration. Moreover, given the pervasive occurrence of diel migrations across aquatic taxa, these findings indicate that individual differences have an important, yet previously unacknowledged role in structuring the temporal and vertical dynamics of aquatic ecosystems. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

  16. The mixed effects of migration: community-level migration and birthweight in Mexico.

    Science.gov (United States)

    Hamilton, Erin R; Choi, Kate H

    2015-05-01

    Research on the relationship between migration and infant health in Mexico finds that migration has mixed impacts on the risk of low birthweight (LBW). Whereas the departure and absence of household and community members are harmful, remittances are beneficial. We extend this work by considering a different measure of infant health in addition to LBW: macrosomia (i.e., heavy birthweight), which is associated with infant, child, and maternal morbidities but has a different social risk profile from LBW. We link the 2008 and 2009 Mexican birth certificates with community data from the 2000 Mexican census to analyze the association between various dimensions of community-level migration (i.e., rates of out-migration, receipt of remittances, and return migration) and the risk of LBW and macrosomia. We examine this association using two sets of models which differ in the extent to which they account for endogeneity. We find that the health impacts of migration differ depending not only on the dimension of migration, but also on the measure of health, and that they are robust to potential sources of endogeneity. Whereas community remittances and return migration are associated with lower risk of LBW, they are associated with increased risk of macrosomia. By contrast, out-migration is associated with increased risk of LBW and lower risk of macrosomia. Our analysis of endogeneity suggests that bias resulting from unmeasured differences between communities with different levels of migration may result in an underestimate of the impacts of community migration on birthweight. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Rapid mineralocorticoid receptor trafficking.

    Science.gov (United States)

    Gekle, M; Bretschneider, M; Meinel, S; Ruhs, S; Grossmann, C

    2014-03-01

    The mineralocorticoid receptor (MR) is a ligand-dependent transcription factor that physiologically regulates water-electrolyte homeostasis and controls blood pressure. The MR can also elicit inflammatory and remodeling processes in the cardiovascular system and the kidneys, which require the presence of additional pathological factors like for example nitrosative stress. However, the underlying molecular mechanism(s) for pathophysiological MR effects remain(s) elusive. The inactive MR is located in the cytosol associated with chaperone molecules including HSP90. After ligand binding, the MR monomer rapidly translocates into the nucleus while still being associated to HSP90 and after dissociation from HSP90 binds to hormone-response-elements called glucocorticoid response elements (GREs) as a dimer. There are indications that rapid MR trafficking is modulated in the presence of high salt, oxidative or nitrosative stress, hypothetically by induction or posttranslational modifications. Additionally, glucocorticoids and the enzyme 11beta hydroxysteroid dehydrogenase may also influence MR activation. Because MR trafficking and its modulation by micro-milieu factors influence MR cellular localization, it is not only relevant for genomic but also for nongenomic MR effects. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Rapid response manufacturing (RRM)

    Energy Technology Data Exchange (ETDEWEB)

    Cain, W.D. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States); Waddell, W.L. [National Centers for Manufacturing Sciences, Ann Arbor, MI (United States)

    1997-02-18

    US industry is fighting to maintain its competitive edge in the global market place. Today markets fluctuate rapidly. Companies, to survive, have to be able to respond with quick-to-market, improved, high quality, cost efficient products. The way products are developed and brought to market can be improved and made more efficient through the proper incorporation of emerging technologies. The RRM project was established to leverage the expertise and resources of US private industries and federal agencies to develop, integrate, and deploy new technologies that meet critical needs for effective product realization. The RRM program addressed a needed change in the US Manufacturing infrastructure that will ensure US competitiveness in world market typified by mass customization. This project provided the effort needed to define, develop and establish a customizable infrastructure for rapid response product development design and manufacturing. A major project achievement was the development of a broad-based framework for automating and integrating the product and process design and manufacturing activities involved with machined parts. This was accomplished by coordinating and extending the application of feature-based product modeling, knowledge-based systems, integrated data management, and direct manufacturing technologies in a cooperative integrated computing environment. Key technological advancements include a product model that integrates product and process data in a consistent, minimally redundant manner, an advanced computer-aided engineering environment, knowledge-based software aids for design and process planning, and new production technologies to make products directly from design application software.

  19. The temporal dynamics of international migration in Europe: Recent trends

    Directory of Open Access Journals (Sweden)

    Jack DeWaard

    2012-06-01

    Full Text Available Descriptive studies of international migration typically rely on measures of migrant stocks and migration rates to assess migration patterns. In this paper, we propose a third alternative. Using harmonized data on age-specific migration flows from and to countries in the European Union (EU and European Free Trade Association (EFTA from 2002-2007, we estimate the waiting time of international migration, i.e., the total time lived by migrants in receiving countries, on average, given period migration and mortality schedules. The results provide a window into the temporal dynamics of international migration in Europe, which are increasingly relevant given recent expansions of the EU.

  20. Interregional migration in socialist countries: the case of China.

    Science.gov (United States)

    Wei, Y

    1997-03-01

    "This paper analyzes changing interregional migration in China and reveals that the recent eastward migration reverses patterns of migration under Mao. It finds that investment variables are more important than the conventional variables of income and job opportunities in determining China's recent interregional migration. It suggests that both state policy and the global force influence interregional migration, challenging the popular view that the socialist state is the only critical determinant. This paper also criticizes Mao's approach to interregional migration and discusses the impact of migration on development." excerpt

  1. Partial diel vertical migrations in pelagic fish.

    Science.gov (United States)

    Mehner, Thomas; Kasprzak, Peter

    2011-07-01

    1. Field studies on diel vertical migration (DVM) usually report uniform behaviour with population-wide ascents and descents during crepuscular periods. This contrasts partial seasonal migrations of many animal populations, where individuals choose either the resident or the migrant strategy depending on population density, feeding opportunity and predation risk in the resident and migrant habitats. 2. We tested whether DVM of freshwater zooplanktivorous fish (Coregonus spp.) resembles partial migrations. Twenty-eight hydroacoustic surveys were performed in the deep Lake Stechlin (Germany) between 2000 and 2010, with samplings encompassing all months between March and December. Zooplankton samples were simultaneously taken in epilimnetic and hypolimnetic layers. Fish obtained from depth-stratified samplings by a midwater trawl were used to test for individual differences between residents and migrants. 3. We show for the first time that DVMs of freshwater fish resemble patterns of partial migrations often found in seasonal environments. Across all samplings, 7-33% of fish did not ascend at dusk, but exhibited the resident strategy. The proportion or residents increased at low zooplankton feeding rates in the daytime habitat and during months when the temperature difference between daytime and night-time habitats was minor. 4. Slightly larger size and higher caloric density of migrants over residents in one of the coexisting Coregonus species suggested that individual differences contributed to the migration strategy performed. However, these results were based on one sample only, and extrapolation to the entire data set is not possible. 5. Our results are indirect evidence that the balance between migrants and residents may primarily depend on the trade-off between feeding gains and metabolic and predation costs of migration. However, the results also suggest that the global fitness consequences for the resident and migrant strategies may not be identical

  2. Father's Labour Migration and Children's School Discontinuation in Rural Mozambique.

    Science.gov (United States)

    Yabiku, Scott T; Agadjanian, Victor

    2017-08-01

    We examine how the discontinuation of schooling among left-behind children is related to multiple dimensions of male labor migration: the accumulation of migration experience, the timing of these migration experiences in the child's life course, and the economic success of the migration. Our setting is rural southern Mozambique, an impoverished area with massive male labor out-migration. Results show that fathers' economically successful labor migration is more beneficial for children's schooling than unsuccessful migration or non-migration. There are large differences, however, by gender: compared to sons of non-migrants, sons of migrant fathers (regardless of migration success) have lower rates of school discontinuation, while daughters of migrant fathers have rates of school discontinuation no different than daughters of non-migrants. Furthermore, accumulated labor migration across the child's life course is beneficial for boys' schooling, but not girls'. Remittances sent in the past year reduce the rate of discontinuation for sons, but not daughters.

  3. Annual spatiotemporal migration schedules in three larger insectivorous birds

    DEFF Research Database (Denmark)

    Jacobsen, Lars Bo; Jensen, Niels Odder; Willemoes, Mikkel

    2017-01-01

    Background: Knowledge of spatiotemporal migration patterns is important for our understanding of migration ecology and ultimately conservation of migratory species. We studied the annual migration schedules of European nightjar, a large nocturnal insectivore and compared it with two other larger ...... for understanding spatiotemporal migration patterns and causes of declines in migratory species.......Background: Knowledge of spatiotemporal migration patterns is important for our understanding of migration ecology and ultimately conservation of migratory species. We studied the annual migration schedules of European nightjar, a large nocturnal insectivore and compared it with two other larger...... the annual migrations of nightjars and swifts and compared these with satellite tracking of cuckoo migration. Results: Individuals of the three species migrated to wintering grounds centered in Central Africa, except some common swifts that remained in West Africa, crossing or circumventing the Sahara along...

  4. Asian migration to Australia: food and health consequences.

    Science.gov (United States)

    Wahlqvist, Mark L

    2002-01-01

    for 'eco-diseases'. In a population probably genetically programmed (but modifiably) in utero to abdominal obesity, diabetes (type II and gestational) and cardiovascular disease, these conditions may be rapidly acquired on migration, along with certain cancers (breast, colo-rectal and prostate). Thus, whilst Asian migration to Australia has provided health opportunities for host citizens, there have been threats to migrant citizens in regard to nutrition-related health.

  5. Modeling cell migration in 3D: Status and challenges

    OpenAIRE

    Rangarajan, Rajagopal; Zaman, Muhammad H.

    2008-01-01

    Cell migration is a multi-scale process that integrates signaling, mechanics and biochemical reaction kinetics. Various mathematical models accurately predict cell migration on 2D surfaces, but are unable to capture the complexities of 3D migration. Additionally, quantitative 3D cell migration models have been few and far between. In this review we look and characterize various mathematical models available in literature to predict cell migration in 3D matrices and analyze their strengths and...

  6. Scale, Diversity, and Determinants of Labour Migration in Europe

    OpenAIRE

    Zaiceva, Anzelika; Zimmermann, Klaus F

    2008-01-01

    While global migration is increasing, internal EU migration flows have remained low. This paper contributes to a better understanding of the determinants and scale of European migration. It surveys previous historical experiences and empirical findings including the recent Eastern enlargements. The determinants of migration before and after the 2004 enlargement and in the EU15 and EU10 countries are analysed using individual data on migration intentions. In addition, perceptions about the siz...

  7. The impact of aging on the scale of migration

    OpenAIRE

    Zaiceva, Anzelika

    2014-01-01

    Population aging will continue in the future, in both developed and developing countries. This may lead to lower migration, since the desire to migrate declines later in the life cycle. In addition, indirect labor demand effects may also reduce migration. However, migration of the elderly, return retirement migration, as well as mobility of certain specialist workers such as health and longer-term care providers, may increase. Also, in a family context, the emigration of children may have sig...

  8. Survival or Accumulation : Migration and rural households in Burkina Faso

    OpenAIRE

    Wouterse, F.S.

    2006-01-01

    Migration plays an important role in development and as a strategy for poverty reduction. Burkina Faso, a country where conditions for agriculture are far from favourable, has a long history of migratory movement. Migration within West Africa (continental migration) has since long taken place in response to drought and low agricultural productivity. Migration to destinations outside the African continent and in particular to Western Europe (intercontinental migration) has become more importan...

  9. Migration and the World of Work: Discursive Constructions of the Global in ILO Narratives About Migration

    NARCIS (Netherlands)

    Amaya Castro, J.M.

    2012-01-01

    This article investigates how a recent report by the ILO works hard to make migration a global phenomenon. The analysis reminds us that reality is never immediately legible; it is always construed discursively and migration is therefore neither inherently local nor global. It is precisely the

  10. Rapid Refresh (RAP) [13 km

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Rapid Refresh (RAP) numerical weather model took the place of the Rapid Update Cycle (RUC) on May 1, 2012. Run by the National Centers for Environmental...

  11. Rapid Refresh (RAP) [20 km

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Rapid Refresh (RAP) numerical weather model took the place of the Rapid Update Cycle (RUC) on May 1, 2012. Run by the National Centers for Environmental...

  12. Kinetics of the different steps during neutrophil migration through cultured endothelial monolayers treated with tumour necrosis factor-alpha.

    Science.gov (United States)

    Luu, N T; Rainger, G E; Nash, G B

    1999-01-01

    To enable a better understanding of the regulation of neutrophil migration, we investigated the kinetics of adhesion and migration over, through and under endothelial monolayers. Neutrophils were perfused over human umbilical vein endothelial cells (HUVEC) which had been treated with tumour necrosis factor-alpha (TNF; 2-1,000 U/ml) for 4 h. Videomicroscopy showed that transendothelial migration was complete within about 5 min of completion of perfusion of a bolus of neutrophils. Separate populations of adherent cells could then be observed, either rolling, migrating over the surface of the HUVEC or migrating underneath, at different characteristic speeds. Increasing concentration of TNF had little effect on the kinetics of migration, but shifted the balance from rolling adhesion to transendothelial migration. When individual neutrophils were followed from the moment they bound to HUVEC treated with 100 U/ml TNF, we found that approximately 40% immobilised essentially immediately on contact, while approximately 40% immobilised after rolling for varying periods (average 26 s) and approximately 20% rolled continuously. Most of the immobilised cells went on to migrate through the monolayer after spending 20-200 s migrating on top, and took about 60 s to pass through. Overall, the time from first binding to completion of transmigration averaged 152 s (range approximately 60-240 s). Interestingly, neutrophils moved relatively slowly on top of the monolayer (about 8 microm/min) but more rapidly underneath (about 16 microm/min). We suggest that the different stages during neutrophil transmigration have characteristic kinetics with separate control mechanisms, which critically influence the efficiency and rate of clearance from the vasculature. Copyright 1999 S. Karger AG, Basel

  13. Skeletonized Least Squares Wave Equation Migration

    KAUST Repository

    Zhan, Ge

    2010-10-17

    The theory for skeletonized least squares wave equation migration (LSM) is presented. The key idea is, for an assumed velocity model, the source‐side Green\\'s function and the geophone‐side Green\\'s function are computed by a numerical solution of the wave equation. Only the early‐arrivals of these Green\\'s functions are saved and skeletonized to form the migration Green\\'s function (MGF) by convolution. Then the migration image is obtained by a dot product between the recorded shot gathers and the MGF for every trial image point. The key to an efficient implementation of iterative LSM is that at each conjugate gradient iteration, the MGF is reused and no new finitedifference (FD) simulations are needed to get the updated migration image. It is believed that this procedure combined with phase‐encoded multi‐source technology will allow for the efficient computation of wave equation LSM images in less time than that of conventional reverse time migration (RTM).

  14. Human neutrophils facilitate tumor cell transendothelial migration.

    LENUS (Irish Health Repository)

    Wu, Q D

    2012-02-03

    Tumor cell extravasation plays a key role in tumor metastasis. However, the precise mechanisms by which tumor cells migrate through normal vascular endothelium remain unclear. In this study, using an in vitro transendothelial migration model, we show that human polymorphonuclear neutrophils (PMN) assist the human breast tumor cell line MDA-MB-231 to cross the endothelial barrier. We found that tumor-conditioned medium (TCM) downregulated PMN cytocidal function, delayed PMN apoptosis, and concomitantly upregulated PMN adhesion molecule expression. These PMN treated with TCM attached to tumor cells and facilitated tumor cell migration through different endothelial monolayers. In contrast, MDA-MB-231 cells alone did not transmigrate. FACScan analysis revealed that these tumor cells expressed high levels of intercellular adhesion molecule-1 (ICAM-1) but did not express CD11a, CD11b, or CD18. Blockage of CD11b and CD18 on PMN and of ICAM-1 on MDA-MB-231 cells significantly attenuated TCM-treated, PMN-mediated tumor cell migration. These tumor cells still possessed the ability to proliferate after PMN-assisted transmigration. These results indicate that TCM-treated PMN may serve as a carrier to assist tumor cell transendothelial migration and suggest that tumor cells can exploit PMN and alter their function to facilitate their extravasation.

  15. Movement ecology of migration in turkey vultures

    Science.gov (United States)

    Mandel, J. T.; Bildstein, K. L.; Bohrer, G.; Winkler, D. W.

    2008-01-01

    We develop individual-based movement ecology models (MEM) to explore turkey vulture (Cathartes aura) migration decisions at both hourly and daily scales. Vulture movements in 10 migration events were recorded with satellite-reporting GPS sensors, and flight behavior was observed visually, aided by on-the-ground VHF radio-tracking. We used the North American Regional Reanalysis dataset to obtain values for wind speed, turbulent kinetic energy (TKE), and cloud height and used a digital elevation model for a measure of terrain ruggedness. A turkey vulture fitted with a heart-rate logger during 124 h of flight during 38 contiguous days showed only a small increase in mean heart rate as distance traveled per day increased, which suggests that, unlike flapping, soaring flight does not lead to greatly increased metabolic costs. Data from 10 migrations for 724 hourly segments and 152 daily segments showed that vultures depended heavily upon high levels of TKE in the atmospheric boundary layer to increase flight distances and maintain preferred bearings at both hourly and daily scales. We suggest how the MEM can be extended to other spatial and temporal scales of avian migration. Our success in relating model-derived atmospheric variables to migration indicates the potential of using regional reanalysis data, as here, and potentially other regional, higher-resolution, atmospheric models in predicting changing movement patterns of soaring birds under various scenarios of climate and land use change. PMID:19060195

  16. A Missing Element in Migration Theories.

    Science.gov (United States)

    Massey, Douglas S

    2015-09-01

    From the mid-1950s through the mid1980s, migration between Mexico and the United States constituted a stable system whose contours were shaped by social and economic conditions well-theorized by prevailing models of migration. It evolved as a mostly circular movement of male workers going to a handful of U.S. states in response to changing conditions of labor supply and demand north and south of the border, relative wages prevailing in each nation, market failures and structural economic changes in Mexico, and the expansion of migrant networks following processes specified by neoclassical economics, segmented labor market theory, the new economics of labor migration, social capital theory, world systems theory, and theoretical models of state behavior. After 1986, however, the migration system was radically transformed, with the net rate of migration increasing sharply as movement shifted from a circular flow of male workers going a limited set of destinations to a nationwide population of settled families. This transformation stemmed from a dynamic process that occurred in the public arena to bring about an unprecedented militarization of the Mexico-U.S. border, and not because of shifts in social, economic, or political factors specified in prevailing theories. In this paper I draw on earlier work to describe that dynamic process and demonstrate its consequences, underscoring the need for greater theoretical attention to the self-interested actions of politicians, pundits, and bureaucrats who benefit from the social construction and political manufacture of immigration crises when none really exist.

  17. Going home: migration as enactment and symbol.

    Science.gov (United States)

    Wright, Susanna

    2009-09-01

    The concepts of home and migration are briefly explored. Reference is made to the reflections of several writers on migration suggesting that migrants may experience alienation, even permanent melancholia. There is discussion of the need to mourn what has been lost and left behind, and of the challenge in analytic work with a migrant to relate to the pain of the individual's core self amid environmental and cultural losses. The paper outlines the history of an individual before her migration from Latin America to London, and tendency to idealize as a new arrival. The symbolization process is discussed and it is suggested that repetitive enactment in the analytic transference may have been needed for her internal reality of estrangement to be confirmed and differentiated from her culturally and socially isolated external life as a migrant. Only then could she mourn losses and symbolize her inner reality. It is suggested that through mourning and symbolization the significance of migration for the patient was worked with and transformed so that, following a second migration, an ordinary, good enough home could be made in a new place.

  18. On the migration rate of tidal meanders

    Science.gov (United States)

    D'Alpaos, A.; Finotello, A.; Ghinassi, M.; Lanzoni, S.; Marani, M.; Rinaldo, A.

    2016-12-01

    Sinuous channels shaped by periodically reversing tidal flows are a ubiquitous feature of tidal landscapes. Despite their fundamental role on the morphology and sedimentary patterns of these landscapes, tidal meanders have received less attention than their fluvial counterparts, particularly as far as migration processes are concerned. We have analyzed the migration of about 300 meander bends in the Northern Venice Lagoon (Italy), from 1968 to nowadays, through observations and modeling interpretation. Similarities with fluvial meanders occur, although important difference also emerge. Meanders cutting through salt-marshes in the Venice Lagoon follow the relationship between Cartesian length and channel width, typical of meanders developed within different settings. We find a mean migration rate of about 0.20 m/year. However, the potential migration rate can reach values of about 0.20 channel widths per year thus suggesting similarities with fluvial meanders. In addition, tidal channel migration dynamics displays features which qualitatively agree with theories developed for the fluvial setting. We deem our results are valuable for the understanding of the morphological evolution and architecture of tidal landscapes, with implications for restoration strategies, also in the face of changes in environmental conditions.

  19. A Missing Element in Migration Theories

    Science.gov (United States)

    Massey, Douglas S.

    2016-01-01

    From the mid-1950s through the mid1980s, migration between Mexico and the United States constituted a stable system whose contours were shaped by social and economic conditions well-theorized by prevailing models of migration. It evolved as a mostly circular movement of male workers going to a handful of U.S. states in response to changing conditions of labor supply and demand north and south of the border, relative wages prevailing in each nation, market failures and structural economic changes in Mexico, and the expansion of migrant networks following processes specified by neoclassical economics, segmented labor market theory, the new economics of labor migration, social capital theory, world systems theory, and theoretical models of state behavior. After 1986, however, the migration system was radically transformed, with the net rate of migration increasing sharply as movement shifted from a circular flow of male workers going a limited set of destinations to a nationwide population of settled families. This transformation stemmed from a dynamic process that occurred in the public arena to bring about an unprecedented militarization of the Mexico-U.S. border, and not because of shifts in social, economic, or political factors specified in prevailing theories. In this paper I draw on earlier work to describe that dynamic process and demonstrate its consequences, underscoring the need for greater theoretical attention to the self-interested actions of politicians, pundits, and bureaucrats who benefit from the social construction and political manufacture of immigration crises when none really exist. PMID:27398085

  20. Managing migration: scaling sovereignty on islands

    Directory of Open Access Journals (Sweden)

    Jenna M. Loyd

    2014-05-01

    Full Text Available Island and maritime spaces between regions have become central places of recurrent crises over human migration and re-articulations of state sovereignty. Islands, the very sites where land meets water, are among the contested sites of struggle over entry and exclusion. In this paper, the Mediterranean is our main area of geographical inquiry. We explore the connections between crises of sovereignty, migration and islands, seeking to enhance connections between scholarship on migration and sovereignty. We argue that migration management and its geographical articulation on islands involve persistent reconfigurations of sovereignty, particularly evident during times of crisis over human migration. Such crises and re-articulations of sovereignty are creative uses of geography that repeatedly lead to a failure to protect human rights. To develop this argument, we bring feminist theorists of state sovereignty into conversation with political geographers. We move across scales of governance and political mobilization to show how a reconfiguration of sovereignty through regional and national management regimes leads to complex legal geographies and sovereign entanglements that migrants and advocates must navigate to claim rights.

  1. Elastic least-squares reverse time migration

    KAUST Repository

    Feng, Zongcai

    2017-03-08

    We use elastic least-squares reverse time migration (LSRTM) to invert for the reflectivity images of P- and S-wave impedances. Elastic LSRTMsolves the linearized elastic-wave equations for forward modeling and the adjoint equations for backpropagating the residual wavefield at each iteration. Numerical tests on synthetic data and field data reveal the advantages of elastic LSRTM over elastic reverse time migration (RTM) and acoustic LSRTM. For our examples, the elastic LSRTM images have better resolution and amplitude balancing, fewer artifacts, and less crosstalk compared with the elastic RTM images. The images are also better focused and have better reflector continuity for steeply dipping events compared to the acoustic LSRTM images. Similar to conventional leastsquares migration, elastic LSRTM also requires an accurate estimation of the P- and S-wave migration velocity models. However, the problem remains that, when there are moderate errors in the velocity model and strong multiples, LSRTMwill produce migration noise stronger than that seen in the RTM images.

  2. Human neutrophils facilitate tumor cell transendothelial migration.

    Science.gov (United States)

    Wu, Q D; Wang, J H; Condron, C; Bouchier-Hayes, D; Redmond, H P

    2001-04-01

    Tumor cell extravasation plays a key role in tumor metastasis. However, the precise mechanisms by which tumor cells migrate through normal vascular endothelium remain unclear. In this study, using an in vitro transendothelial migration model, we show that human polymorphonuclear neutrophils (PMN) assist the human breast tumor cell line MDA-MB-231 to cross the endothelial barrier. We found that tumor-conditioned medium (TCM) downregulated PMN cytocidal function, delayed PMN apoptosis, and concomitantly upregulated PMN adhesion molecule expression. These PMN treated with TCM attached to tumor cells and facilitated tumor cell migration through different endothelial monolayers. In contrast, MDA-MB-231 cells alone did not transmigrate. FACScan analysis revealed that these tumor cells expressed high levels of intercellular adhesion molecule-1 (ICAM-1) but did not express CD11a, CD11b, or CD18. Blockage of CD11b and CD18 on PMN and of ICAM-1 on MDA-MB-231 cells significantly attenuated TCM-treated, PMN-mediated tumor cell migration. These tumor cells still possessed the ability to proliferate after PMN-assisted transmigration. These results indicate that TCM-treated PMN may serve as a carrier to assist tumor cell transendothelial migration and suggest that tumor cells can exploit PMN and alter their function to facilitate their extravasation.

  3. Developing Physician Migration Estimates for Workforce Models.

    Science.gov (United States)

    Holmes, George M; Fraher, Erin P

    2017-02-01

    To understand factors affecting specialty heterogeneity in physician migration. Physicians in the 2009 American Medical Association Masterfile data were matched to those in the 2013 file. Office locations were geocoded in both years to one of 293 areas of the country. Estimated utilization, calculated for each specialty, was used as the primary predictor of migration. Physician characteristics (e.g., specialty, age, sex) were obtained from the 2009 file. Area characteristics and other factors influencing physician migration (e.g., rurality, presence of teaching hospital) were obtained from various sources. We modeled physician location decisions as a two-part process: First, the physician decides whether to move. Second, conditional on moving, a conditional logit model estimates the probability a physician moved to a particular area. Separate models were estimated by specialty and whether the physician was a resident. Results differed between specialties and according to whether the physician was a resident in 2009, indicating heterogeneity in responsiveness to policies. Physician migration was higher between geographically proximate states with higher utilization for that specialty. Models can be used to estimate specialty-specific migration patterns for more accurate workforce modeling, including simulations to model the effect of policy changes. © Health Research and Educational Trust.

  4. Movement ecology of migration in turkey vultures.

    Science.gov (United States)

    Mandel, J T; Bildstein, K L; Bohrer, G; Winkler, D W

    2008-12-09

    We develop individual-based movement ecology models (MEM) to explore turkey vulture (Cathartes aura) migration decisions at both hourly and daily scales. Vulture movements in 10 migration events were recorded with satellite-reporting GPS sensors, and flight behavior was observed visually, aided by on-the-ground VHF radio-tracking. We used the North American Regional Reanalysis dataset to obtain values for wind speed, turbulent kinetic energy (TKE), and cloud height and used a digital elevation model for a measure of terrain ruggedness. A turkey vulture fitted with a heart-rate logger during 124 h of flight during 38 contiguous days showed only a small increase in mean heart rate as distance traveled per day increased, which suggests that, unlike flapping, soaring flight does not lead to greatly increased metabolic costs. Data from 10 migrations for 724 hourly segments and 152 daily segments showed that vultures depended heavily upon high levels of TKE in the atmospheric boundary layer to increase flight distances and maintain preferred bearings at both hourly and daily scales. We suggest how the MEM can be extended to other spatial and temporal scales of avian migration. Our success in relating model-derived atmospheric variables to migration indicates the potential of using regional reanalysis data, as here, and potentially other regional, higher-resolution, atmospheric models in predicting changing movement patterns of soaring birds under various scenarios of climate and land use change.

  5. Migration highways and migration barriers created by host-parasite interactions.

    Science.gov (United States)

    Zhang, Quan-Guo; Buckling, Angus

    2016-12-01

    Co-evolving parasites may play a key role in host migration and population structure. Using co-evolving bacteria and viruses, we test general hypotheses as to how co-evolving parasites affect the success of passive host migration between habitats that can support different intensities of host-parasite interactions. First, we show that parasites aid migration from areas of intense to weak co-evolutionary interactions and impede migration in the opposite direction, as a result of intraspecific apparent competition mediated via parasites. Second, when habitats show qualitative difference such that some environments support parasite persistence while others do not, different population regulation forces (either parasitism or competitive exclusion) will reduce the success of migration in both directions. Our study shows that co-evolution with parasites can predictably homogenises or isolates host populations, depending on heterogeneity of abiotic conditions, with the second scenario constituting a novel type of 'isolation by adaptation'. © 2016 John Wiley & Sons Ltd/CNRS.

  6. Globalization of international migration: Social challenges and policy implication

    Directory of Open Access Journals (Sweden)

    I A Aleshkovski

    2017-12-01

    Full Text Available In the second half of the XX century, the humankind witnessed the insurmountable and irreversible power of globalization processes, which influence all spheres of social life and establish a global system of interdependency between countries and nations. Globalization within impetuous changes in global political, social and economic systems has determined dramatic shifts in the international migration processes that lead to the new stage of migration history. In nowadays globalized world, international migration has become a reality for almost all corners of the globe. The author considers features of the recent trends of international migration: the unprecedented growth of the international migration flows; the widening geography of international migration that involves nearly all countries of the world; qualitative changes in the structure of international migration flows; the key role of economic migration; the permanent growth and structural intricateness of irregular migration; the increasing scale and geographical widening of forced migration; the growing importance of international migration for the demographic development of the world, countries of both origin and destination. All these trends combined prove that the international migration patterns have become more complex. The author analyzes the legal framework of the international migration processes, and gives recommendations on the ways to improve the control and regulation of migration processes. Specific issues related to the social challenges of international migration are also discussed in the article.

  7. Migration Theories and Mental Health in Toni Morrison's Jazz

    Directory of Open Access Journals (Sweden)

    Leila Tafreshi Motalgh

    2015-01-01

    Full Text Available This article aims to elaborate the relationship between migration and mental health problems that are evident in migrant women in Toni Morrison's Jazz (1992. To this end, pre-migration, migration and post-migration stress factors are identified in the novel based on Danish Bhugra's theory of migration. It seems that pre-migration stress factors and traumas are associated with the push theory of migration, while post-migration stresses are associated with the pull theory of migration. Despite post-migration stresses, the main female characters who encounter pre-migration stress factors and traumas are more likely to develop mental health problems like Post-traumatic Stress Disorder (PTSD. Although there is extensive literary criticism of Jazz (1992, no theoretical criticism exists that simultaneously covers migration theories and the mental health problems evident in Toni Morrison's female characters. It is worth highlighting that gender is a variable that correlates positively with migration and mental health. This article attempts to fill a gap in literary criticism and contribute to the body of research on mental health problems associated with gender and migration. Keywords: Push-Pull Theory, Great Migration, Black Studies, Gender, Trauma, PTSD

  8. Rapid chemical separations

    CERN Document Server

    Trautmann, N

    1976-01-01

    A survey is given on the progress of fast chemical separation procedures during the last few years. Fast, discontinuous separation techniques are illustrated by a procedure for niobium. The use of such techniques for the chemical characterization of the heaviest known elements is described. Other rapid separation methods from aqueous solutions are summarized. The application of the high speed liquid chromatography to the separation of chemically similar elements is outlined. The use of the gas jet recoil transport method for nuclear reaction products and its combination with a continuous solvent extraction technique and with a thermochromatographic separation is presented. Different separation methods in the gas phase are briefly discussed and the attachment of a thermochromatographic technique to an on-line mass separator is shown. (45 refs).

  9. From the countryside to the cities: a comparative historical analysis of rural-urban migration in Russia and in the Soviet Union during the industrialization drive.

    Science.gov (United States)

    Sokolov, A K

    1991-01-01

    The author analyzes the rapid process of urbanization (which involved large-scale rural-urban migration) that occurred in the USSR during its industrialization during the 1930s. Data are from official Soviet sources, including the censuses of 1918, 1926, and 1939. The author examines factors that attracted migrants to cities as well as those that drove them from the countryside. The system of internal passports and residence stamps that was developed to control internal migration is described.

  10. Carbon export by vertically migrating zooplankton

    DEFF Research Database (Denmark)

    Hansen, Agnethe Nøhr; Visser, André W.

    2016-01-01

    of the active transport of carbon by different size fractions of the migrating zooplankton population as function of time and space. The approach is motivated by the difficulty in incorporating behavioral aspects of carbon transport into large scale carbon budgets of the world's oceans. The results show......Through diel vertical migration (DVM), zooplankton add an active transport to the otherwise passive sinking of detrital material that constitutes the biological pump. This active transport has proven difficult to quantify. We present a model that estimates both the temporal and depth characteristic...... that despite their lower abundance, large zooplankton (length circa 1–2 mm) migrate deeper and transport approximately twice as much carbon as do the smaller zooplankton (length circa 0.2–0.3 mm). In mid- latitudes (∼30°N to ∼45°N), where pronounced spring blooms are observed, up to 20% more carbon...

  11. Multiples least-squares reverse time migration

    KAUST Repository

    Zhang, Dongliang

    2013-01-01

    To enhance the image quality, we propose multiples least-squares reverse time migration (MLSRTM) that transforms each hydrophone into a virtual point source with a time history equal to that of the recorded data. Since each recorded trace is treated as a virtual source, knowledge of the source wavelet is not required. Numerical tests on synthetic data for the Sigsbee2B model and field data from Gulf of Mexico show that MLSRTM can improve the image quality by removing artifacts, balancing amplitudes, and suppressing crosstalk compared to standard migration of the free-surface multiples. The potential liability of this method is that multiples require several roundtrips between the reflector and the free surface, so that high frequencies in the multiples are attenuated compared to the primary reflections. This can lead to lower resolution in the migration image compared to that computed from primaries.

  12. Boundary migration during recrystallization: experimental observations

    DEFF Research Database (Denmark)

    Zhang, Yubin; Juul Jensen, Dorte

    2015-01-01

    materials. This type of analysis has largely been based on the assumption that all or groups of recrystallizing grains grow in the same uniform manner, therefore the results represent average growth behaviors on a macro scale. Recently, significant efforts have been made to quantify the boundary migration......Quantitative analysis of boundary migration during recrystallization is a key task to understand the recrystallization process and to improve recrystallization models. In the last 25-30 years, quantification of boundary migration has mostly been conducted in term of average growth rates in many...... during recrystallization on local grain scales, using different advanced experimental characterization and computer simulation techniques. This paper aims at summarizing these recent achievements with focus on the potentials of the various advanced experimental characterization techniques. Suggestions...

  13. Psychosis and migration: does a correlation exist?

    Science.gov (United States)

    Mandaglio, Chiara; Maierà, Enza

    2014-11-01

    The mental health of migrants is considered today one of the major problems of individual and public health. Unlike other European countries, such as England and France, where migration is linked to a colonial past, Italy has only recently found itself faced with a tumultuous transformation of identity, becoming from a country of emigration, an immigration country. In light of all this, this work stems from the need to shed light on the relationship between social integration and development of psychiatric disorders in migrants, with particular attention to the correlation between migration and psychotic pathology. Finally, the elaboration of various issues related to the migration process will be dealt with, placing the priority on investigating the greater psychiatric morbidity in migrants compared with natives.

  14. DESIGNING THE RETURN MIGRATION OF ROMANIAN STUDENTS

    Directory of Open Access Journals (Sweden)

    Magdalena VELCIU

    2017-05-01

    Full Text Available Romanian youth migration is an increasing phenomenon, due to subjective and objective factors as economical reasons, professional carrer and increasingly more international competition for talent. In these circumstances, the present article aims to evaluate determinant factors that contribute to the decision of Romanian graduates to return national labour market. We sustain that young Romanians consider carefully and hardly decide their professional future. A particular attention is given to their personal reasons and motivations as well as family and friends network. For designing returning factors we present the results of a questionnaire survey, asking young pupils and students about their future educational way and personal reasons underlying the decision to study in a foreign country and taking into consideration the returning decision. As far international student migration is seen as a first step to migration for work, our work desires to fight for returning home of Romanian well-educated graduates.

  15. On the interrelations between migration and commuting

    Directory of Open Access Journals (Sweden)

    Lukić Vesna

    2013-01-01

    Full Text Available In this paper, we emphasise the significance of studying the interrelations between commuting and migration. The aim of the paper is to point out the factors which affect these interrelations (demographic and socio-economic characteristics of migrants and commuters, labour market, real estate market, information, life style, etc., with the special emphasis on the role of commuting distance onto the chosen mobility type. Besides theorethical frameworks and results of the selected foreign researches up to date, the overview of research of interrelations between migration and commuting in Serbia has also been presented. While earlier studies conducted by Gawryszenski (1978, Termote (1980 and Reitsma&Vergoossen (1987 pointed to the replacement of migration types between each other within country, in recent literature the interaction between migration and commuting has been studied in a trans-boundary context of the contemporary EU. Modern trend of long distance commuting instead of migration and the concept of substitution/replacement regarding migration and commuting have also been discussed. In Serbia, there is a positive correlation between commuting outflows and immigration in rural settlements of Vojvodina province. Namely, commuting and migration are complement, which is the characteristic of both processes sub-urbanisation and ex-urbanisation (Lukić, 2012. In addition to ownership of real estate and previous migration experience, marital status influenced the chosen mobility type in Serbia as well. Adjustment to changes of Serbian labour market is mostly conducted via migration (Miletić, Lukić, Miljanović, 2011. Interrelations between migration and commuting are very significant due to the tendency of transformation of some commuters into migrants. This process has its consequences, both on demographic as well as the overall socio-economic development of the area of commuters’ origin and destination. However, even though the surveys

  16. Engendering climate change-induced migration

    Science.gov (United States)

    Caretta, Martina Angela; Miletto, Michela

    2017-04-01

    Climate change leads to increased climate variability, which is manifest in extreme weather events such as floods and droughts. These put at stake agricultural productivity, forestry, inland fisheries, aquaculture, water supply and sanitation which in turn hamper poorest householdś self-sufficiency and capability to cope with risks. Due to the risk of losing or the actual loss of livelihood, farmers in the Global South must look for alternative strategies to diversify risk. Migration is one of those strategies, which that can be seen either as an adaptive measure or an indicator of limits to adaptation to environmental stress. 60% of young migrants live in the Global South (UN, 2013). Many internally displaced people in the world are under the age of 18, some move with their families, other, mostly in South Asia and West Africa, migrate alone. Youth, as all migrants, are seeking better economic opportunities to support themselves and their families. Migration is a gendered process which plays out differently in diverse societies depending on local cultural norms that do not only affect and are affected by gender roles, but also by age, class and ethnicity. Threats to water availability, access and water hazards have diverse impacts on men and women. The link gender and climate-induced migration is still under investigation and few studies provide concrete country specific examples of this phenomenon. Our paper will present a state of the art literature review around climate-induced migration in the Global South from a gender perspective showing how meńs and womeńs migratory decisions, patterns and outcomes differ at the stage pre-during post migration.

  17. Migration and health: fact, fiction, art, politics

    Directory of Open Access Journals (Sweden)

    Tam Clarence C

    2006-10-01

    Full Text Available Abstract The recent Immigration Bill debate in the United States Congress has again re-ignited the polemic regarding immigration policy. In this essay, I argue that disputes surrounding the legality of migrant workers highlight chronic, underlying problems related to factors that drive migration. The public health field, although concerned primarily with addressing the health needs of migrant populations, cannot remain disengaged from the wider debates about migration. The health needs of migrants, although in themselves important, are merely symptoms of deeper structural process that are intrinsically linked to equity and human rights, and simply focusing on health issues will be insufficient to address these societal pathologies.

  18. SCANDINAVIAN MIGRATION IN THE VIKING AGE

    Directory of Open Access Journals (Sweden)

    Wladyslaw Duczko

    2011-01-01

    Full Text Available Movements of Scandinavians in period between late 8th AD to middle of 11th AD, called Viking Age, were combined military actions-piracy – and migrations with goal to colonize territories in the West Europe – mainly Insular world of Atlantic and British isles, but also in East Europe, among Finno-Ugrians and Slavs. This activity is seen as the recent, and last, of the Migration Period, the time of great movements of Germanic people in the 4th century AD.

  19. Transit Migration in North Cyprus (TRNC

    Directory of Open Access Journals (Sweden)

    Yılmaz Çolak

    2014-12-01

    Full Text Available This study aims at exploring the flows of transit migration to North Cyprus by type: whether or not it is labour, refugee or asylum. To determine that, the question of which push factors lay behind transit migration in the origin country tries to be answered. Also this study seeks to analyze origins, routes and destinations of transit migrants in TRNC from 2004 to 2008. In addition, the paper analyzes what kind of measures TRNC government was taking to deal with illegal transit migrants, human trafficking and smuggling through its borders, and how non-state institutions in TRNC considered and dealt with transit migrants and especially refugees.

  20. Stretch due to Penile Prosthesis Reservoir Migration

    Directory of Open Access Journals (Sweden)

    E. Baten

    2016-03-01

    Full Text Available A 43-year old patient presented to the emergency department with stretch, due to impossible deflation of the penile prosthesis, 4 years after successful implant. A CT-scan showed migration of the reservoir to the left rectus abdominis muscle. Refilling of the reservoir was inhibited by muscular compression, causing stretch. Removal and replacement of the reservoir was performed, after which the prosthesis was well-functioning again. Migration of the penile prosthesis reservoir is extremely rare but can cause several complications, such as stretch.