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Sample records for increased migration rate

  1. Rating Migration and Bond Valuation: Decomposing Rating Migration Matrices from Market Data via Default Probability Term Structures

    Directory of Open Access Journals (Sweden)

    Brian BARNARD

    2017-09-01

    Full Text Available The study builds on previous research that decomposes rating category default probability term structures from rating category interest rate term structures, and proposes a method to decompose rating migration matrices from market data, via decomposed default probability term structures. To investigate the power and accuracy of the proposed method, it was examined to what extent an existing, known rating migration matrix could again be surfaced by the method. Overall, the results are more than satisfactory, and the method promises to be accurate. Although not considered here, the main objective is the application of the method to market data. The outcome should be insightful in itself, and can be used to evaluate historical rating migration matrices commonly devised by rating agencies, and to form a better understanding of the default probability term structures embedded in market data.

  2. Thalidomide increases human keratinocyte migration and proliferation.

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    Nasca, M R; O'Toole, E A; Palicharla, P; West, D P; Woodley, D T

    1999-11-01

    Thalidomide is reported to have therapeutic utility in the treatment of pyoderma gangrenosum, Behçet's disease, aphthous ulcers, and skin wounds. We investigated the effect of thalidomide on human keratinocyte proliferation and migration, two early and critical events in the re-epithelialization of skin wounds. Thalidomide at concentrations less than 1 microM did not affect keratinocyte viability. Using a thymidine incorporation assay, we found that thalidomide, at therapeutic concentrations, induced more than a 2. 5-fold increase in the proliferative potential of the cells. Keratinocyte migration was assessed by two independent motility assays: a colloidal gold assay and an in vitro scratch assay. At optimal concentrations, thalidomide increased keratinocyte migration on a collagen matrix more than 2-fold in the colloidal gold assay and more than 3-fold in the scratch assay over control. Although pro-migratory, thalidomide did not alter the level of metalloproteinase-9 secreted into culture medium. Thalidomide did, however, induce a 2-4-fold increase in keratinocyte-derived interleukin-8, a pro-migratory cellular autocrine factor. Human keratinocyte migration and proliferation are essential for re-epithelialization of skin wounds. Interleukin-8 increases human keratinocyte migration and proliferation and is chemotactic for keratinocytes. Therefore, thalidomide may modulate keratinocyte proliferation and motility by a chemokine-dependent pathway.

  3. Migration Rate Of Tidal Meanders: Inferences From The Venice Lagoon

    Science.gov (United States)

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

    2015-12-01

    Meandering channels are ubiquitous features of tidal landscapes. However, despite their fundamental role on the eco-morphodynamic evolution of these landscapes, tidal meanders have received less attention when compared to their fluvial counterparts. Improving current understanding of tidal meander migration, a largely-examined topic in fluvial landscapes, is a key step to highlight analogies and differences between tidal and fluvial cases. The migration of about 400 meander bends, belonging to 40 salt-marsh channels in the Northern Venice Lagoon (Italy), from 1968 to nowadays, has been investigated by means of both a classical method in fluvial frameworks and new procedure. Similarities with fluvial meanders occur, although important difference also emerge. Meanders cutting through the San Felice marsh follow the relationship between cartesian length and channel width, typical of meanders developed within different settings. However, meander migration rates proved to be smaller than those characterizing fluvial meanders. Indeed, the analysis of meander migration suggests a mean migration rate of about 0.10 m/year, consistent with the few data available in the literature. As for the fluvial case, the maximum-potential migration rate (i.e. the envelope curve of the relationship between migration rate and bend radius, both divided by channel width) reaches a maximum for radius-over-width ratio included between 2 and 3, regardless of the considered method. Nevertheless, the new-proposed method allows us to provide a more objective and continuous characterization. By using this new procedure, the channel curvature has finally been Fourier-analyzed, confirming the importance of even harmonics along the curvature spectrum. A correlation between migration rates and dominant harmonics seems to drive the evolution of tidal meanders and might represent a key-feature to distinguish them from their fluvial counterparts.

  4. Approximate Bayesian computation for modular inference problems with many parameters: the example of migration rates.

    Science.gov (United States)

    Aeschbacher, S; Futschik, A; Beaumont, M A

    2013-02-01

    We propose a two-step procedure for estimating multiple migration rates in an approximate Bayesian computation (ABC) framework, accounting for global nuisance parameters. The approach is not limited to migration, but generally of interest for inference problems with multiple parameters and a modular structure (e.g. independent sets of demes or loci). We condition on a known, but complex demographic model of a spatially subdivided population, motivated by the reintroduction of Alpine ibex (Capra ibex) into Switzerland. In the first step, the global parameters ancestral mutation rate and male mating skew have been estimated for the whole population in Aeschbacher et al. (Genetics 2012; 192: 1027). In the second step, we estimate in this study the migration rates independently for clusters of demes putatively connected by migration. For large clusters (many migration rates), ABC faces the problem of too many summary statistics. We therefore assess by simulation if estimation per pair of demes is a valid alternative. We find that the trade-off between reduced dimensionality for the pairwise estimation on the one hand and lower accuracy due to the assumption of pairwise independence on the other depends on the number of migration rates to be inferred: the accuracy of the pairwise approach increases with the number of parameters, relative to the joint estimation approach. To distinguish between low and zero migration, we perform ABC-type model comparison between a model with migration and one without. Applying the approach to microsatellite data from Alpine ibex, we find no evidence for substantial gene flow via migration, except for one pair of demes in one direction. © 2013 Blackwell Publishing Ltd.

  5. On a Corporate Bond Pricing Model with Credit Rating Migration Risksand Stochastic Interest Rate

    Directory of Open Access Journals (Sweden)

    Jin Liang

    2017-10-01

    Full Text Available In this paper we study a corporate bond-pricing model with credit rating migration and astochastic interest rate. The volatility of bond price in the model strongly depends on potential creditrating migration and stochastic change of the interest rate. This new model improves the previousexisting models in which the interest rate is considered to be a constant. The existence, uniquenessand regularity of the solution for the model are established. Moreover, some properties includingthe smoothness of the free boundary are obtained. Furthermore, some numerical computations arepresented to illustrate the theoretical results.

  6. Estimated migration rates under scenarios of global climate change.

    Science.gov (United States)

    Jay R. Malcolm; Adam Markham; Ronald P. Neilson; Michael. Oaraci

    2002-01-01

    Greefihouse-induced warming and resulting shifts in climatic zones may exceed the migration capabilities of some species. We used fourteen combinations of General Circulation Models (GCMs) and Global Vegetation Models (GVMs) to investigate possible migration rates required under CO2 doubled climatic forcing.

  7. Angiotensin II type 2 receptor stimulation increases the rate of NG108-15 cell migration via actin depolymerization.

    Science.gov (United States)

    Kilian, Peter; Campbell, Shirley; Bilodeau, Lyne; Guimond, Marie-Odile; Roberge, Claude; Gallo-Payet, Nicole; Payet, Marcel Daniel

    2008-06-01

    Angiotensin II (Ang II) has been reported to induce migration in neuronal cell types. Using time-lapse microscopy, we show here that Ang II induces acceleration in NG108-15 cell migration. This effect was antagonized by PD123319, a selective AT2 receptor antagonist, but not by DUP753, a selective AT1 receptor antagonist, and was mimicked by the specific AT2 receptor agonist CGP42112. This Ang II-induced acceleration was not sensitive to the inhibition of previously described signaling pathways of the AT2 receptor, guanylyl cyclase/cyclic GMP or p42/p44 mapk cascades, but was abolished by pertussis toxin treatment and involved PP2A activation. Immunofluorescence studies indicate that Ang II or CGP42112 decreased the amount of filamentous actin at the leading edge of the cells. This decrease was accompanied by a concomitant increase in globular actin levels. Regulation of actin turnover in actin-based motile systems is known to be mainly under the control of the actin depolymerizing factor and cofilin. Basal migration speed decreased by 77.2% in cofilin-1 small interfering RNA-transfected NG108-15 cells, along with suppression of the effect of Ang II. In addition, the Ang II-induced increase in cell velocity was abrogated in serum-free medium as well as by genistein or okadaic acid treatment in a serum-containing medium. Such results indicate that the AT2 receptor increases the migration speed of NG108-15 cells and involves a tyrosine kinase activity, followed by phosphatase activation, which may be of the PP2A type. Therefore, the present study identifies actin depolymerization and cofilin as new targets of AT2 receptor action, in the context of cellular migration.

  8. MIGRATION RATES OF PLANETS DUE TO SCATTERING OF PLANETESIMALS

    International Nuclear Information System (INIS)

    Ormel, C. W.; Ida, S.; Tanaka, H.

    2012-01-01

    Planets migrate due to the recoil they experience from scattering solid (planetesimal) bodies. To first order, the torques exerted by the interior and exterior disks will cancel, analogous to the cancellation of the torques from the gravitational interaction with the gas (Type-I migration). Assuming the dispersion-dominated regime and power laws characterized by indices α and β for the surface density and eccentricity profiles, we calculate the net torque on the planet. We consider both distant encounters and close (orbit-crossing) encounters. We find that the close and distant encounter torques have opposite signs with respect to α and β; and that the torque is especially sensitive to the eccentricity gradient β. Compared to Type-I migration due to excitation of density waves, the planetesimal-driven migration rate is generally lower due to the lower surface density of solids in gas-rich disk, although this may be partially or fully offset when their eccentricity and inclinaton are small. Allowing for the feedback of the planet on the planetesimal disk through viscous stirring, we find that under certain conditions a self-regulated migration scenario emerges, in which the planet migrates at a steady pace that approaches the rate corresponding to the one-sided torque. If the ratio of the local disk mass in planetesimals to planet mass is low, however, migration will stall. We quantify the boundaries separating the three accretion regimes.

  9. Migration rates of brine inclusions in single crystals of NaCl

    International Nuclear Information System (INIS)

    Chou, I.M.

    1982-01-01

    Rock-salt deposits have been considered as a possible medium for the permanent storage of high-level radioactive wastes and spent fuel. Brine inclusions present in natural salt can migrate toward the waste if the temperature and the temperature gradients in the vicinity of the radioactive waste are large enough. This migration is due to the dissolution of salt at the hot side of the salt-brine interface, ion diffusion through the brine droplet, and the precipitation of salt at the cold side of the salt brine interface. In order to quantify the problem, the migration rate of these brine inclusions must be estimated under various repository conditions. This paper estimates migration rates for all-liquid brine inclusions in single crystals of NaCl by utilizing recent data for brines and the model of Anthony and Cline [T.R. Anthony and H.E. Cline, J. Appl. Phys., 42, pp. 3380-387 (1971)]. The predictions are compared with experimentally measured migration rates. 4 figures, 6 tables

  10. Inference of historical changes in migration rate from the lengths of migrant tracts

    DEFF Research Database (Denmark)

    Pool, John E; Nielsen, Rasmus

    2009-01-01

    After migrant chromosomes enter a population, they are progressively sliced into smaller pieces by recombination. Therefore, the length distribution of "migrant tracts" (chromosome segments with recent migrant ancestry) contains information about historical patterns of migration. Here we introduce...... a theoretical framework describing the migrant tract length distribution and propose a likelihood inference method to test demographic hypotheses and estimate parameters related to a historical change in migration rate. Applying this method to data from the hybridizing subspecies Mus musculus domesticus and M....... m. musculus, we find evidence for an increase in the rate of hybridization. Our findings could indicate an evolutionary trajectory toward fusion rather than speciation in these taxa....

  11. Lactobacillus rhamnosus GG Lysate Increases Re-Epithelialization of Keratinocyte Scratch Assays by Promoting Migration.

    Science.gov (United States)

    Mohammedsaeed, Walaa; Cruickshank, Sheena; McBain, Andrew J; O'Neill, Catherine A

    2015-11-05

    A limited number of studies have investigated the potential of probiotics to promote wound healing in the digestive tract. The aim of the current investigation was to determine whether probiotic bacteria or their extracts could be beneficial in cutaneous wound healing. A keratinocyte monolayer scratch assay was used to assess re-epithelialization; which comprises keratinocyte proliferation and migration. Primary human keratinocyte monolayers were scratched then exposed to lysates of Lactobacillus (L) rhamnosus GG, L. reuteri, L. plantarum or L. fermentum. Re-epithelialization of treated monolayers was compared to that of untreated controls. Lysates of L. rhamnosus GG and L. reuteri significantly increased the rate of re-epithelialization, with L. rhamnosus GG being the most efficacious. L. reuteri increased keratinocyte proliferation while L. rhamnosus GG lysate significantly increased proliferation and migration. Microarray analysis of L. rhamnosus GG treated scratches showed increased expression of multiple genes including the chemokine CXCL2 and its receptor CXCR2. These are involved in normal wound healing where they stimulate keratinocyte proliferation and/or migration. Increased protein expression of both CXCL2 and CXCR2 were confirmed by ELISA and immunoblotting. These data demonstrate that L. rhamnosus GG lysate accelerates re-epithelialization of keratinocyte scratch assays, potentially via chemokine receptor pairs that induce keratinocyte migration.

  12. Characterizing and modelling river channel migration rates at a regional scale: Case study of south-east France.

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    Alber, Adrien; Piégay, Hervé

    2017-11-01

    An increased awareness by river managers of the importance of river channel migration to sediment dynamics, habitat complexity and other ecosystem functions has led to an advance in the science and practice of identifying, protecting or restoring specific erodible corridors across which rivers are free to migrate. One current challenge is the application of these watershed-specific goals at the regional planning scales (e.g., the European Water Framework Directive). This study provides a GIS-based spatial analysis of the channel migration rates at the regional-scale. As a case study, 99 reaches were sampled in the French part of the Rhône Basin and nearby tributaries of the Mediterranean Sea (111,300 km 2 ). We explored the spatial correlation between the channel migration rate and a set of simple variables (e.g., watershed area, channel slope, stream power, active channel width). We found that the spatial variability of the channel migration rates was primary explained by the gross stream power (R 2  = 0.48) and more surprisingly by the active channel width scaled by the watershed area. The relationship between the absolute migration rate and the gross stream power is generally consistent with the published empirical models for freely meandering rivers, whereas it is less significant for the multi-thread reaches. The discussion focused on methodological constraints for a regional-scale modelling of the migration rates, and the interpretation of the empirical models. We hypothesize that the active channel width scaled by the watershed area is a surrogate for the sediment supply which may be a more critical factor than the bank resistance for explaining the regional-scale variability of the migration rates. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Epidemic spread in coupled populations with seasonally varying migration rates

    Science.gov (United States)

    Muzyczyn, Adam; Shaw, Leah B.

    2009-03-01

    The H5N1 strain of avian influenza has spread worldwide, and this spread may be due to seasonal migration of birds and mixing of birds from different regions in the wintering grounds. We studied a multipatch model for avian influenza with seasonally varying migration rates. The bird population was divided into two spatially distinct patches, or subpopulations. Within each patch, the disease followed the SIR (susceptible-infected-recovered) model for epidemic spread. Migration rates were varied periodically, with a net flux toward the breeding grounds during the spring and towards the wintering grounds during the fall. The case of two symmetric patches reduced to single-patch SIR dynamics. However, asymmetry in the birth and contact rates in the breeding grounds and wintering grounds led to bifurcations to longer period orbits and chaotic dynamics. We studied the bifurcation structure of the model and the phase relationships between outbreaks in the two patches.

  14. Field migration rates of tidal meanders recapitulate fluvial morphodynamics

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    Finotello, Alvise; Lanzoni, Stefano; Ghinassi, Massimiliano; Marani, Marco; Rinaldo, Andrea; D'Alpaos, Andrea

    2018-02-01

    The majority of tidal channels display marked meandering features. Despite their importance in oil-reservoir formation and tidal landscape morphology, questions remain on whether tidal-meander dynamics could be understood in terms of fluvial processes and theory. Key differences suggest otherwise, like the periodic reversal of landscape-forming tidal flows and the widely accepted empirical notion that tidal meanders are stable landscape features, in stark contrast with their migrating fluvial counterparts. On the contrary, here we show that, once properly normalized, observed migration rates of tidal and fluvial meanders are remarkably similar. Key to normalization is the role of tidal channel width that responds to the strong spatial gradients of landscape-forming flow rates and tidal prisms. We find that migration dynamics of tidal meanders agree with nonlinear theories for river meander evolution. Our results challenge the conventional view of tidal channels as stable landscape features and suggest that meandering tidal channels recapitulate many fluvial counterparts owing to large gradients of tidal prisms across meander wavelengths.

  15. Effect of increasing nitrobenzene loading rates on the performance of anaerobic migrating blanket reactor and sequential anaerobic migrating blanket reactor/completely stirred tank reactor system

    International Nuclear Information System (INIS)

    Kuscu, Ozlem Selcuk; Sponza, Delia Teresa

    2009-01-01

    A laboratory scale anaerobic migrating blanket reactor (AMBR) reactor was operated at nitrobenzene (NB) loading rates increasing from 3.33 to 66.67 g NB/m 3 day and at a constant hydraulic retention time (HRT) of 6 days to observe the effects of increasing NB concentrations on chemical oxygen demand (COD), NB removal efficiencies, bicarbonate alkalinity, volatile fatty acid (VFA) accumulation and methane gas percentage. Moreover, the effect of an aerobic completely stirred tank reactor (CSTR) reactor, following the anaerobic reactor, on treatment efficiencies was also investigated. Approximately 91-94% COD removal efficiencies were observed up to a NB loading rate of 30.00 g/m 3 day in the AMBR reactor. The COD removal efficiencies decreased from 91% to 85% at a NB loading rate of 66.67 g/m 3 day. NB removal efficiencies were approximately 100% at all NB loading rates. The maximum total gas, methane gas productions and methane percentage were found to be 4.1, 2.6 l/day and 59%, respectively, at a NB loading rate of 30.00 g/m 3 day. The optimum pH values were found to be between 7.2 and 8.4 for maximum methanogenesis. The total volatile fatty acid (TVFA) concentrations in the effluent were 110 and 70 mg/l in the first and second compartments at NB loading rates as high as 66.67 and 6.67 g/m 3 day, respectively, while they were measured as zero in the effluent of the AMBR reactor. In this study, from 180 mg/l NB 66 mg/l aniline was produced in the anaerobic reactor while aniline was completely removed and transformed to 2 mg/l of cathechol in the aerobic CSTR reactor. Overall COD removal efficiencies were found to be 95% and 99% for NB loading rates of 3.33 and 66.67 g/m 3 day in the sequential anaerobic AMBR/aerobic CSTR reactor system, respectively. The toxicity tests performed with Photobacterium phosphoreum (LCK 480, LUMIStox) and Daphnia magna showed that the toxicity decreased with anaerobic/aerobic sequential reactor system from the influent, anaerobic and to

  16. Field migration rates of tidal meanders recapitulate fluvial morphodynamics.

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    Finotello, Alvise; Lanzoni, Stefano; Ghinassi, Massimiliano; Marani, Marco; Rinaldo, Andrea; D'Alpaos, Andrea

    2018-02-13

    The majority of tidal channels display marked meandering features. Despite their importance in oil-reservoir formation and tidal landscape morphology, questions remain on whether tidal-meander dynamics could be understood in terms of fluvial processes and theory. Key differences suggest otherwise, like the periodic reversal of landscape-forming tidal flows and the widely accepted empirical notion that tidal meanders are stable landscape features, in stark contrast with their migrating fluvial counterparts. On the contrary, here we show that, once properly normalized, observed migration rates of tidal and fluvial meanders are remarkably similar. Key to normalization is the role of tidal channel width that responds to the strong spatial gradients of landscape-forming flow rates and tidal prisms. We find that migration dynamics of tidal meanders agree with nonlinear theories for river meander evolution. Our results challenge the conventional view of tidal channels as stable landscape features and suggest that meandering tidal channels recapitulate many fluvial counterparts owing to large gradients of tidal prisms across meander wavelengths. Copyright © 2018 the Author(s). Published by PNAS.

  17. Indonesia's migration transition.

    Science.gov (United States)

    Hugo, G

    1995-01-01

    This article describes population movements in Indonesia in the context of rapid and marked social and economic change. Foreign investment in Indonesia is increasing, and global mass media is available to many households. Agriculture is being commercialized, and structural shifts are occurring in the economy. Educational levels are increasing, and women's role and status are shifting. Population migration has increased over the decades, both short and long distance, permanent and temporary, legal and illegal, and migration to and between urban areas. This article focuses specifically on rural-to-urban migration and international migration. Population settlements are dense in the agriculturally rich inner areas of Java, Bali, and Madura. Although the rate of growth of the gross domestic product was 6.8% annually during 1969-94, the World Bank ranked Indonesia as a low-income economy in 1992 because of the large population size. Income per capita is US $670. Indonesia is becoming a large exporter of labor to the Middle East, particularly women. The predominance of women as overseas contract workers is changing women's role and status in the family and is controversial due to the cases of mistreatment. Malaysia's high economic growth rate of over 8% per year means an additional 1.3 million foreign workers and technicians are needed. During the 1980s urban growth increased at a very rapid rate. Urban growth tended to occur along corridors and major transportation routes around urban areas. It is posited that most of the urban growth is due to rural-to-urban migration. Data limitations prevent an exact determination of the extent of rural-to-urban migration. More women are estimated to be involved in movements to cities during the 1980s compared to the 1970s. Recruiters and middlemen have played an important role in rural-to-urban migration and international migration.

  18. GABAergic anxiolytic drug in water increases migration behaviour in salmon

    Science.gov (United States)

    Hellström, Gustav; Klaminder, Jonatan; Finn, Fia; Persson, Lo; Alanärä, Anders; Jonsson, Micael; Fick, Jerker; Brodin, Tomas

    2016-12-01

    Migration is an important life-history event in a wide range of taxa, yet many migrations are influenced by anthropogenic change. Although migration dynamics are extensively studied, the potential effects of environmental contaminants on migratory physiology are poorly understood. In this study we show that an anxiolytic drug in water can promote downward migratory behaviour of Atlantic salmon (Salmo salar) in both laboratory setting and in a natural river tributary. Exposing salmon smolt to a dilute concentration of a GABAA receptor agonist (oxazepam) increased migration intensity compared with untreated smolt. These results implicate that salmon migration may be affected by human-induced changes in water chemical properties, such as acidification and pharmaceutical residues in wastewater effluent, via alterations in the GABAA receptor function.

  19. Determinants of the Egyptian labour migration.

    Science.gov (United States)

    Kandil, M; Metwally, M

    1992-03-01

    The objective is to summarize the pattern of Egyptian migration to Arab oil-producing countries (AOPC), to review some factors that are important determinants of labor movement based on theory, and to empirically model the migration rate to AOPC and to Saudi Arabia. Factors are differentiated as to their relative importance. Push factors are the low wages, high inflation rate, and high population density in Egypt; pull factors are higher wages. It is predicted that an increase in income from destination countries has a significant positive impact on the migration rate. An increase in population density stimulates migration. An increase in inflation acts to increase out-migration with a 2-year lag, which accommodates departure preparation. Egypt's experience with labor migration is described for the pre-oil boom, and the post-oil boom. Several estimates of labor migration are given. Government policy toward migration is positive. Theory postulates migration to be determined by differences in the availability of labor, labor rewards between destination and origin, and the cost of migration. In the empirical model, push factors are population density, the current inflation rate, and the ratio of income/capita in AOPC to Egypt. The results indicate that the ratio of income/capita had a strong pull impact and population density had a strong push impact. The inflation rate has a positive impact with a lag estimated at 2 years. Prior to the Camp David Accord, there was a significant decrease in the number of Egyptian migrants due to political tension. The findings support the classical theory of factor mobility. The consequences of migration on the Egyptian economy have been adverse. Future models should disaggregate data because chronic shortages exist in some parts of the labor market. Manpower needs assessment would be helpful for policy makers.

  20. In vitro human keratinocyte migration rates are associated with SNPs in the KRT1 interval.

    Directory of Open Access Journals (Sweden)

    Heng Tao

    Full Text Available Efforts to develop effective therapeutic treatments for promoting fast wound healing after injury to the epidermis are hindered by a lack of understanding of the factors involved. Re-epithelialization is an essential step of wound healing involving the migration of epidermal keratinocytes over the wound site. Here, we examine genetic variants in the keratin-1 (KRT1 locus for association with migration rates of human epidermal keratinocytes (HEK isolated from different individuals. Although the role of intermediate filament genes, including KRT1, in wound activated keratinocytes is well established, this is the first study to examine if genetic variants in humans contribute to differences in the migration rates of these cells. Using an in vitro scratch wound assay we observe quantifiable variation in HEK migration rates in two independent sets of samples; 24 samples in the first set and 17 samples in the second set. We analyze genetic variants in the KRT1 interval and identify SNPs significantly associated with HEK migration rates in both samples sets. Additionally, we show in the first set of samples that the average migration rate of HEK cells homozygous for one common haplotype pattern in the KRT1 interval is significantly faster than that of HEK cells homozygous for a second common haplotype pattern. Our study demonstrates that genetic variants in the KRT1 interval contribute to quantifiable differences in the migration rates of keratinocytes isolated from different individuals. Furthermore we show that in vitro cell assays can successfully be used to deconstruct complex traits into simple biological model systems for genetic association studies.

  1. Increased migration of monocytes in essential hypertension is associated with increased transient receptor potential channel canonical type 3 channels

    DEFF Research Database (Denmark)

    Zhao, Zhigang; Ni, Yinxing; Chen, Jing

    2012-01-01

    Increased transient receptor potential canonical type 3 (TRPC3) channels have been observed in patients with essential hypertension. In the present study we tested the hypothesis that increased monocyte migration is associated with increased TRPC3 expression. Monocyte migration assay was performe...

  2. SITE-94. Estimated rates of redox-front migration in granitic rocks

    International Nuclear Information System (INIS)

    Arthur, R.C.

    1996-10-01

    Analytical models for the rate of migration of oxidizing groundwaters are derived based on the stationary-state approximation to coupled fluid flow and water-rock interaction, and are constrained by molar concentrations of ferrous silicate, oxide, and sulfide minerals in the granites and associated fractures comprising the host rock beneath Aespoe. Model results indicate that small amounts of ferrous minerals in Aespoe granites and fractures will retard the downward migration of oxidizing conditions that could be generated by infiltration of glacial meltwaters during periods of glacial maxima and retreat. Calculated front velocities are retarded relative to Darcy fluxes observed in conductive fracture zones at Aespoe (0.3 to 3 m/y) by factors ranging from 10 -3 to 10 -4 . Corresponding times for the front to migrate 500 m vary from 5,100 to 4,400,000 years. Retardation efficiency depends on mineralogy and decreases in the order: fractures > altered granites > unaltered granite. The most conductive structures in these rocks are therefore the most efficient in limiting the rate of front migration. Periods of recharge during glaciation are comparable to times required for an oxidizing front to migrate to repository levels. This suggests an oxidizing front could reach repository depths during a single glacial-interglacial event. The persistence of oxidizing conditions could be relatively short lived, however, because reversal of flow conditions driven by the advance and retreat of ice sheets could cause reducing conditions to be restored. 27 refs

  3. Migration and health in an increasingly diverse Europe.

    Science.gov (United States)

    Rechel, Bernd; Mladovsky, Philipa; Ingleby, David; Mackenbach, Johan P; McKee, Martin

    2013-04-06

    The share of migrants in European populations is substantial and growing, despite a slowdown in immigration after the global economic crisis. This paper describes key aspects of migration and health in Europe, including the scale of international migration, available data for migrant health, barriers to accessing health services, ways of improving health service provision to migrants, and migrant health policies that have been adopted across Europe. Improvement of migrant health and provision of access for migrants to appropriate health services is not without challenges, but knowledge about what steps need to be taken to achieve these aims is increasing. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. A floating bridge disrupts seaward migration and increases mortality of steelhead smolts in Hood Canal, Washington state.

    Directory of Open Access Journals (Sweden)

    Megan Moore

    Full Text Available Habitat modifications resulting from human transportation and power-generation infrastructure (e.g., roads, dams, bridges can impede movement and alter natural migration patterns of aquatic animal populations, which may negatively affect survival and population viability. Full or partial barriers are especially problematic for migratory species whose life histories hinge on habitat connectivity.The Hood Canal Bridge, a floating structure spanning the northern outlet of Hood Canal in Puget Sound, Washington, extends 3.6 meters underwater and forms a partial barrier for steelhead migrating from Hood Canal to the Pacific Ocean. We used acoustic telemetry to monitor migration behavior and mortality of steelhead smolts passing four receiver arrays and several single receivers within the Hood Canal, Puget Sound, and Strait of Juan de Fuca. Twenty-seven mortality events were detected within the vicinity of the Hood Canal Bridge, while only one mortality was recorded on the other 325 receivers deployed throughout the study area. Migrating steelhead smolts were detected at the Hood Canal Bridge array with greater frequency, on more receivers, and for longer durations than smolts migrating past three comparably configured arrays. Longer migration times and paths are likely to result in a higher density of smolts near the bridge in relation to other sites along the migration route, possibly inducing an aggregative predator response to steelhead smolts.This study provides strong evidence of substantial migration interference and increased mortality risk associated with the Hood Canal Bridge, and may partially explain low early marine survival rates observed in Hood Canal steelhead populations. Understanding where habitat modifications indirectly increase predation pressures on threatened populations helps inform potential approaches to mitigation.

  5. A floating bridge disrupts seaward migration and increases mortality of steelhead smolts in Hood Canal, Washington state.

    Science.gov (United States)

    Moore, Megan; Berejikian, Barry A; Tezak, Eugene P

    2013-01-01

    Habitat modifications resulting from human transportation and power-generation infrastructure (e.g., roads, dams, bridges) can impede movement and alter natural migration patterns of aquatic animal populations, which may negatively affect survival and population viability. Full or partial barriers are especially problematic for migratory species whose life histories hinge on habitat connectivity. The Hood Canal Bridge, a floating structure spanning the northern outlet of Hood Canal in Puget Sound, Washington, extends 3.6 meters underwater and forms a partial barrier for steelhead migrating from Hood Canal to the Pacific Ocean. We used acoustic telemetry to monitor migration behavior and mortality of steelhead smolts passing four receiver arrays and several single receivers within the Hood Canal, Puget Sound, and Strait of Juan de Fuca. Twenty-seven mortality events were detected within the vicinity of the Hood Canal Bridge, while only one mortality was recorded on the other 325 receivers deployed throughout the study area. Migrating steelhead smolts were detected at the Hood Canal Bridge array with greater frequency, on more receivers, and for longer durations than smolts migrating past three comparably configured arrays. Longer migration times and paths are likely to result in a higher density of smolts near the bridge in relation to other sites along the migration route, possibly inducing an aggregative predator response to steelhead smolts. This study provides strong evidence of substantial migration interference and increased mortality risk associated with the Hood Canal Bridge, and may partially explain low early marine survival rates observed in Hood Canal steelhead populations. Understanding where habitat modifications indirectly increase predation pressures on threatened populations helps inform potential approaches to mitigation.

  6. Migration and opportunistic feeding increase PCB accumulation in Arctic seabirds.

    Science.gov (United States)

    Baert, J M; Janssen, C R; Borgå, K; De Laender, F

    2013-10-15

    It is widely accepted that body concentrations of persistent organic pollutants (POPs) tend to increase with trophic level (TL). Yet, little attention has been paid to the causes in the underlying differences in POP body concentrations between species occupying similar TLs. In this paper we use two modeling approaches to quantify the importance of migration and opportunistic feeding, relative to that of trophic level, in explaining interspecific differences in polychlorinated biphenyl (PCB) body concentrations between 6 Arctic seabird species breeding in the Barents Sea: Little Auk (Alle alle), Black Guillemot (Cepphus grylle), Brünnich's Guillemot (Uria lomvia), Common Eider (Somateria mollissima), Black-legged Kittiwake (Rissa tridactyla), and Glaucous Gull (Larus hyperboreus). As a first approach, we use additive models to analyze two independent data sets (n = 470 and n = 726). We demonstrate that migration, opportunistic feeding, and TL significantly (p < 0.001) increase PCB body concentrations by a factor 3.61-4.10, 2.66-20.95, and 2.38-2.41, respectively. Our second approach, using a mechanistic bioaccumulation model, confirmed these positive effects on the body burdens but suggested lower effects of migration, opportunistic feeding, and TL (1.55, 2.39, and 2.38) than did our statistical analysis. These two independent approaches demonstrate that the effects of migration and opportunistic feeding on seabird body burdens can be similar to that of an increase of one TL and should therefore be accounted for in future analyses.

  7. Constitutively active ezrin increases membrane tension, slows migration, and impedes endothelial transmigration of lymphocytes in vivo in mice.

    Science.gov (United States)

    Liu, Yin; Belkina, Natalya V; Park, Chung; Nambiar, Raj; Loughhead, Scott M; Patino-Lopez, Genaro; Ben-Aissa, Khadija; Hao, Jian-Jiang; Kruhlak, Michael J; Qi, Hai; von Andrian, Ulrich H; Kehrl, John H; Tyska, Matthew J; Shaw, Stephen

    2012-01-12

    ERM (ezrin, radixin moesin) proteins in lymphocytes link cortical actin to plasma membrane, which is regulated in part by ERM protein phosphorylation. To assess whether phosphorylation of ERM proteins regulates lymphocyte migration and membrane tension, we generated transgenic mice whose T-lymphocytes express low levels of ezrin phosphomimetic protein (T567E). In these mice, T-cell number in lymph nodes was reduced by 27%. Lymphocyte migration rate in vitro and in vivo in lymph nodes decreased by 18% to 47%. Lymphocyte membrane tension increased by 71%. Investigations of other possible underlying mechanisms revealed impaired chemokine-induced shape change/lamellipod extension and increased integrin-mediated adhesion. Notably, lymphocyte homing to lymph nodes was decreased by 30%. Unlike most described homing defects, there was not impaired rolling or sticking to lymph node vascular endothelium but rather decreased migration across that endothelium. Moreover, decreased numbers of transgenic T cells in efferent lymph suggested defective egress. These studies confirm the critical role of ERM dephosphorylation in regulating lymphocyte migration and transmigration. Of particular note, they identify phospho-ERM as the first described regulator of lymphocyte membrane tension, whose increase probably contributes to the multiple defects observed in the ezrin T567E transgenic mice.

  8. Population, migration and urbanization.

    Science.gov (United States)

    1982-06-01

    Despite recent estimates that natural increase is becoming a more important component of urban growth than rural urban transfer (excess of inmigrants over outmigrants), the share of migration in the total population growth has been consistently increasing in both developed and developing countries. From a demographic perspective, the migration process involves 3 elements: an area of origin which the mover leaves and where he or she is considered an outmigrant; the destination or place of inmigration; and the period over which migration is measured. The 2 basic types of migration are internal and international. Internal migration consists of rural to urban migration, urban to urban migration, rural to rural migration, and urban to rural migration. Among these 4 types of migration various patterns or processes are followed. Migration may be direct when the migrant moves directly from the village to the city and stays there permanently. It can be circular migration, meaning that the migrant moves to the city when it is not planting season and returns to the village when he is needed on the farm. In stage migration the migrant makes a series of moves, each to a city closer to the largest or fastest growing city. Temporary migration may be 1 time or cyclical. The most dominant pattern of internal migration is rural urban. The contribution of migration to urbanization is evident. For example, the rapid urbanization and increase in urban growth from 1960-70 in the Republic of Korea can be attributed to net migration. In Asia the largest component of the population movement consists of individuals and groups moving from 1 rural location to another. Recently, because urban centers could no longer absorb the growing number of migrants from other places, there has been increased interest in the urban to rural population redistribution. This reverse migration also has come about due to slower rates of employment growth in the urban centers and improved economic opportunities

  9. Chemically-induced liquid film migration with low lattice diffusivity relative to the migration rate in Mo-Ni-(W)

    International Nuclear Information System (INIS)

    Lee, K.R.

    1992-01-01

    This paper reports that when a 90Mo-10Ni alloy (by wt) liquid phase sintered at 1400 degrees C is heat-treated at 1400 degrees C after replacing the matrix with a melt of 44Ni-34Mo-22W (by wt), the liquid films between the grains migrate, leaving behind an Mo alloy enriched with W. The ratio of the lattice diffusivity of W in Mo, D, to the initial migration velocity, v. (D/v) is estimated to be between 0.03 and 0.18 angstrom. Hence it appears that there is no lattice diffusion of W ahead of the migrating liquid film, and is such a case the driving force has been suggested to be the chemical free energy. But the observed v is approximately same as that to be expected if the driving force is assumed to be diffusional coherency strain energy. Likewise, a previous study of den Broeder and Nakahara shows that the rate of chemically-induced grain boundary migration in Cu-Ni shows a smooth variation with temperature as D/v decreases from values much larger than the interatomic spacing to values much smaller with decreasing temperature. The coherency strain energy thus appears to be a general driving force for the migration even when the apparent diffusion length indicated by D/v is smaller than the interatomic spacing

  10. Variation of 137Cs migration parameters in soils

    International Nuclear Information System (INIS)

    Silant'ev, A.N.; Shkuratova, I.G.

    1988-01-01

    Quasidiffusion model accounting the oriented migration is used to describe the observed profiles of 137 Cs distribution in soil. A way of model use in case of real soil, the quasidiffusion migration factor being varied, is suggested. It is shown that in the upper thin soil layer the quasidiffusion migration factor and oriented migration rate values are constant. With further increase of depth the quasidiffusion coefficient grows, the oriented migration rate is unchanged. On the basis of location data characteristic values of migration parameters for different soils of the USSR European territory depending on the soil texture, vegetative cover and moistening are determined

  11. (2008) SWJ:21-25 Comparative Studies On the Dying rate Migration

    African Journals Online (AJOL)

    Dr. Ahmed

    COMPARATIVE STUDIES ON DYEING RATE MIGRATION AND WASH FASTNESS PROPERTIES OF AZO DYES. DERIVED FROM ..... The dyeing of Cellulose Fibres Publication thrust,. London. Standard methods for determination of fastness properties of textiles and leather, 4th Edition. 1978. Soceity of dyers and ...

  12. 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.

  13. TAXATION AND INTERNAL MIGRATION - EVIDENCE FROM THE SWISS CENSUS USING COMMUNITY-LEVEL VARIATION IN INCOME TAX RATES

    OpenAIRE

    Liebig, Thomas; Puhani, Patrick A.; Sousa-Poza, Alfonso

    2006-01-01

    We investigate the relationship between income tax rate variation and internal migration for the unique case of Switzerland, whose system of determining tax rates primarily at the community level results in enough variation to permit analysis of their influence on migration. Specifically, using Swiss census data, we analyze migratory responses to tax rate variations for various groups defined by age, education, and nationality/residence permit. The results suggest that young Swiss college gra...

  14. Migration background and juvenile mental health: a descriptive retrospective analysis of diagnostic rates of psychiatric disorders in young people

    Directory of Open Access Journals (Sweden)

    Tilman Jakob Gaber

    2013-06-01

    Full Text Available Introduction: This article presents diagnostic rates for specific mental disorders in a German pediatric inpatient population over a period of 20 years with respect to migration background and socioeconomic status (SES. Methods: Diagnostic data were obtained over a period of 20 years from 8,904 patients who visited a child and adolescent psychiatry mental health service in Germany. Data from 5,985 diagnosed patients (ICD-9 and ICD-10 criteria were included with respect to gender, migration background, and SES. Results:Migration- and gender-specific effects were found for both periods of assessment. The group of boys with a migration background showed significantly higher rates of reactions to severe stress, adjustment disorders, and posttraumatic stress disorder compared to their male, non-migrant counterparts. Conversely, boys without a migration background showed a significantly higher percentage rate of hyperkinetic disorders than male migrants. Similar results were found for female migrants in the latter assessment period (ICD-10. In addition, female migrants showed lower rates of emotional disorders whose onset occurs in childhood compared to their non-migrant counterparts. Conclusions: Data from this investigation provide preliminary evidence that the prevalence of various psychiatric disorders in children and adolescents is influenced by migration background and SES.

  15. Shear-induced particle migration in suspensions of rods

    Energy Technology Data Exchange (ETDEWEB)

    Mondy, L.A. (Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)); Brenner, H. (Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)); Altobelli, S.A. (The Lovelace Institutes, 2425 Ridgecrest Drive, S. E., Albuquerque, New Mexico 87108 (United States)); Abbott, J.R.; Graham, A.L. (Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States))

    1994-03-01

    Shear-induced migration of particles occurs in suspensions of neutrally buoyant spheres in Newtonian fluids undergoing shear in the annular space between two rotating, coaxial cylinders (a wide-gap Couette), even when the suspension is in creeping flow. Previous studies have shown that the rate of migration of spherical particles from the high-shear-rate region near the inner (rotating) cylinder to the low-shear-rate region near the outer (stationary) cylinder increases rapidly with increasing sphere size. To determine the effect of particle shape, the migration of rods suspended in Newtonian fluids was recently measured. The behavior of several suspensions was studied. Each suspension contained well-characterized, uniform rods with aspect ratios ranging from 2 to 18 at either 0.30 or 0.40 volume fraction. At the same volume fraction of solids, the steady-state, radial concentration profiles for rods were independent of aspect ratio and were indistinguishable from those obtained from suspended spheres. Only minor differences near the walls (attributable to the finite size of the rods relative to the curvature of the walls) appeared to differentiate the profiles. Data taken during the transition from a well-mixed suspension to the final steady state show that the rate of migration increased as the volume of the individual rods increased.

  16. Migration and the Wage Curve:

    DEFF Research Database (Denmark)

    Brücker, Herbert; Jahn, Elke J.

    in a general equilibrium framework. For the empirical analysis we employ the IABS, a two percent sample of the German labor force. We find that the elasticity of the wage curve is particularly high for young workers and workers with a university degree, while it is low for older workers and workers......  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...

  17. Migration processes and self-rated health among marriage migrants in South Korea.

    Science.gov (United States)

    Chang, Hsin-Chieh; Wallace, Steven P

    2016-01-01

    Research on migrant health mostly examines labor migrants, with some attention paid to the trauma faced by refugees. Marriage migrants represent an understudied vulnerable population in the migration and health literature. Drawing on a Social Determinants of Health (SDH) approach, we use a large Korean national survey and stratified multivariate regressions to examine the link between migration processes and the self-rated health of Korea's three largest ethnic groups of marriage migrants: Korean-Chinese, Vietnamese, and Han Chinese. We find that post-migration socioeconomic status and several social integration factors are associated with the health of marriage migrants of all three groups. Specifically, having more social relationships with Koreans is associated with good health among marriage migrants, while having more social relationships with co-ethnics is associated with worse health. Marriage migrants' perceived social status of their natal and marital families is a better predictor of their health than more objective measures such as their education attainment and that of their Korean husbands. The post-migration social gradients among all ethnic groups demonstrate a dose-response effect of marital family's social standing on marriage migrants' health, independent of their own education and the social standing of their natal families. Lastly, we find some ethnicity-specific predictors such as the association between higher educational level and worse health status among the Vietnamese. This variability by group suggests a more complex set of SDH occurred during the marriage migration processes than a basic SDH framework would predict. Using a new immigrant destination, South Korea, as an example, we conclude that migration and health policies that reduce ethnicity-specific barriers and offer integration programs in early post-migration stages may offer a pathway to good health among marriage migrants.

  18. The impact of small irrigation diversion dams on the recent migration rates of steelhead and redband trout (Oncorhynchus mykiss)

    Science.gov (United States)

    Weigel, Dana E.; Connolly, Patrick J.; Powell, Madison S.

    2013-01-01

    Barriers to migration are numerous in stream environments and can occur from anthropogenic activities (such as dams and culverts) or natural processes (such as log jams or dams constructed by beaver (Castor canadensis)). Identification of barriers can be difficult when obstructions are temporary or incomplete providing passage periodically. We examine the effect of several small irrigation diversion dams on the recent migration rates of steelhead (Oncorhynchus mykiss) in three tributaries to the Methow River, Washington. The three basins had different recent migration patterns: Beaver Creek did not have any recent migration between sites, Libby Creek had two-way migration between sites and Gold Creek had downstream migration between sites. Sites with migration were significantly different from sites without migration in distance, number of obstructions, obstruction height to depth ratio and maximum stream gradient. When comparing the sites without migration in Beaver Creek to the sites with migration in Libby and Gold creeks, the number of obstructions was the only significant variable. Multinomial logistic regression identified obstruction height to depth ratio and maximum stream gradient as the best fitting model to predict the level of migration among sites. Small irrigation diversion dams were limiting population interactions in Beaver Creek and collectively blocking steelhead migration into the stream. Variables related to stream resistance (gradient, obstruction number and obstruction height to depth ratio) were better predictors of recent migration rates than distance, and can provide important insight into migration and population demographic processes in lotic species.

  19. Analysis of migration rate and chemotaxis of human adipose-derived mesenchymal stem cells in response to LPS and LTA in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Herzmann, Nicole; Salamon, Achim [Department of Cell Biology, University Medicine Rostock, Schillingallee 69, D-18057 Rostock (Germany); Fiedler, Tomas [Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Schillingallee 70, D-18057 Rostock (Germany); Peters, Kirsten, E-mail: kirsten.peters@med.uni-rostock.de [Department of Cell Biology, University Medicine Rostock, Schillingallee 69, D-18057 Rostock (Germany)

    2016-03-15

    Mesenchymal stem cells (MSC) are able to stimulate the regeneration of injured tissue. Since bacterial infections are common complications in wound healing, bacterial pathogens and their components come into direct contact with MSC. The interaction with bacterial structures influences the proliferation, differentiation and migratory activity of the MSC, which might be of relevance during regeneration. Studies on MSC migration in response to bacterial components have shown different results depending on the cell type. Here, we analyzed the migration rate and chemotaxis of human adipose-derived MSC (adMSC) in response to the basic cell-wall components lipopolysaccharide (LPS) of Gram-negative bacteria and lipoteichoic acid (LTA) of Gram-positive bacteria in vitro. To this end, we used transwell and scratch assays, as well as a specific chemotaxis assay combined with live-cell imaging. We found no significant influence of LPS or LTA on the migration rate of adMSC in transwell or scratch assays. Furthermore, in the µ-slide chemotaxis assay, the stimulation with LPS did not exert any chemotactic effect on adMSC. - Highlights: • LPS increased the release of IL-6 and IL-8 in adMSC significantly. • The migration rate of adMSC was not influenced by LPS or LTA. • LPS or LTA did not exert a chemotactic effect on adMSC.

  20. Analysis of migration rate and chemotaxis of human adipose-derived mesenchymal stem cells in response to LPS and LTA in vitro

    International Nuclear Information System (INIS)

    Herzmann, Nicole; Salamon, Achim; Fiedler, Tomas; Peters, Kirsten

    2016-01-01

    Mesenchymal stem cells (MSC) are able to stimulate the regeneration of injured tissue. Since bacterial infections are common complications in wound healing, bacterial pathogens and their components come into direct contact with MSC. The interaction with bacterial structures influences the proliferation, differentiation and migratory activity of the MSC, which might be of relevance during regeneration. Studies on MSC migration in response to bacterial components have shown different results depending on the cell type. Here, we analyzed the migration rate and chemotaxis of human adipose-derived MSC (adMSC) in response to the basic cell-wall components lipopolysaccharide (LPS) of Gram-negative bacteria and lipoteichoic acid (LTA) of Gram-positive bacteria in vitro. To this end, we used transwell and scratch assays, as well as a specific chemotaxis assay combined with live-cell imaging. We found no significant influence of LPS or LTA on the migration rate of adMSC in transwell or scratch assays. Furthermore, in the µ-slide chemotaxis assay, the stimulation with LPS did not exert any chemotactic effect on adMSC. - Highlights: • LPS increased the release of IL-6 and IL-8 in adMSC significantly. • The migration rate of adMSC was not influenced by LPS or LTA. • LPS or LTA did not exert a chemotactic effect on adMSC.

  1. Migration and health in an increasingly diverse Europe

    NARCIS (Netherlands)

    Rechel, B.; Mladovsky, P.; Ingleby, D.; Mackenbach, J.P.; McKee, M.

    2013-01-01

    The share of migrants in European populations is substantial and growing, despite a slowdown in immigration after the global economic crisis. This paper describes key aspects of migration and health in Europe, including the scale of international migration, available data for migrant health,

  2. Phosphorus vertical migration in aquic brown soil and light chernozem under different phosphorous application rate: a soil column leaching experiment.

    Science.gov (United States)

    Zhao, Muqiu; Chen, Xin; Shi, Yi; Zhou, Quanlai; Lu, Caiyan

    2009-01-01

    A soil column leaching experiment was conducted to study the vertical migration of phosphorus in aquic brown soil and light chernozem under different phosphorus fertilization rates. The results showed that total dissolved phosphorus concentration in the leachates from the two soils was nearly the same, but dissolved inorganic phosphorus concentration was obviously different. In all fertilization treatments, aquic brown soil had a higher content of phosphorus in calcium chloride extracts compared with light chernozem. But Olsen phosphorus content was higher at the soil depth beneath 0-20 cm, and increased with increasing phosphorus application rate.

  3. Credit risk migration rates modeling as open systems: A micro-simulation approach

    Science.gov (United States)

    Landini, S.; Uberti, M.; Casellina, S.

    2018-05-01

    The last financial crisis of 2008 stimulated the development of new Regulatory Criteria (commonly known as Basel III) that pushed the banking activity to become more prudential, either in the short and the long run. As well known, in 2014 the International Accounting Standards Board (IASB) promulgated the new International Financial Reporting Standard 9 (IFRS 9) for financial instruments that will become effective in January 2018. Since the delayed recognition of credit losses on loans was identified as a weakness in existing accounting standards, the IASB has introduced an Expected Loss model that requires more timely recognition of credit losses. Specifically, new standards require entities to account both for expected losses from when the impairments are recognized for the first time and for full loan lifetime; moreover, a clear preference toward forward looking models is expressed. In this new framework, it is necessary a re-thinking of the widespread standard theoretical approach on which the well known prudential model is founded. The aim of this paper is then to define an original methodological approach to migration rates modeling for credit risk which is innovative respect to the standard method from the point of view of a bank as well as in a regulatory perspective. Accordingly, the proposed not-standard approach considers a portfolio as an open sample allowing for entries, migrations of stayers and exits as well. While being consistent with the empirical observations, this open-sample approach contrasts with the standard closed-sample method. In particular, this paper offers a methodology to integrate the outcomes of the standard closed-sample method within the open-sample perspective while removing some of the assumptions of the standard method. Three main conclusions can be drawn in terms of economic capital provision: (a) based on the Markovian hypothesis with a-priori absorbing state at default, the standard closed-sample method is to be abandoned

  4. Exploring the Climate Change, Migration and Conflict Nexus

    Science.gov (United States)

    Burrows, Kate; Kinney, Patrick L.

    2016-01-01

    The potential link between climate change, migration, and conflict has been widely discussed and is increasingly viewed by policy makers as a security issue. However, considerable uncertainty remains regarding the role that climate variability and change play among the many drivers of migration and conflict. The overall objective of this paper is to explore the potential pathways linking climate change, migration and increased risk of conflict. We review the existing literature surrounding this issue and break the problem into two components: the links between climate change and migration, and those between migration and conflict. We found a large range of views regarding the importance of climate change as a driver for increasing rates of migration and subsequently of conflict. We argue that future research should focus not only on the climate-migration-conflict pathway but also work to understand the other pathways by which climate variability and change might exacerbate conflict. We conclude by proposing five questions to help guide future research on the link between climate change, migration, and conflict. PMID:27110806

  5. Exploring the Climate Change, Migration and Conflict Nexus

    Directory of Open Access Journals (Sweden)

    Kate Burrows

    2016-04-01

    Full Text Available The potential link between climate change, migration, and conflict has been widely discussed and is increasingly viewed by policy makers as a security issue. However, considerable uncertainty remains regarding the role that climate variability and change play among the many drivers of migration and conflict. The overall objective of this paper is to explore the potential pathways linking climate change, migration and increased risk of conflict. We review the existing literature surrounding this issue and break the problem into two components: the links between climate change and migration, and those between migration and conflict. We found a large range of views regarding the importance of climate change as a driver for increasing rates of migration and subsequently of conflict. We argue that future research should focus not only on the climate-migration-conflict pathway but also work to understand the other pathways by which climate variability and change might exacerbate conflict. We conclude by proposing five questions to help guide future research on the link between climate change, migration, and conflict.

  6. Exploring the Climate Change, Migration and Conflict Nexus.

    Science.gov (United States)

    Burrows, Kate; Kinney, Patrick L

    2016-04-22

    The potential link between climate change, migration, and conflict has been widely discussed and is increasingly viewed by policy makers as a security issue. However, considerable uncertainty remains regarding the role that climate variability and change play among the many drivers of migration and conflict. The overall objective of this paper is to explore the potential pathways linking climate change, migration and increased risk of conflict. We review the existing literature surrounding this issue and break the problem into two components: the links between climate change and migration, and those between migration and conflict. We found a large range of views regarding the importance of climate change as a driver for increasing rates of migration and subsequently of conflict. We argue that future research should focus not only on the climate-migration-conflict pathway but also work to understand the other pathways by which climate variability and change might exacerbate conflict. We conclude by proposing five questions to help guide future research on the link between climate change, migration, and conflict.

  7. Sedimentation rate and lateral migration of tidal channels in the Lagoon of Venice (Northern Italy)

    Science.gov (United States)

    Donnici, Sandra; Madricardo, Fantina; Serandrei-Barbero, Rossana

    2017-11-01

    Tidal channels are crucial for the functioning of highly valuable coastal environments, such as estuaries and lagoons. Their properties, however, are currently less understood than those of river systems. To elucidate their past behaviour, an extensive geophysical investigation was performed to reconstruct the evolution of channels and tidal surfaces in the central part of the Lagoon of Venice (Italy) over the past 5000 years. Comparing high-spatial-resolution acoustic data and sedimentary facies analyses of 41 cores, 29 of which were radiocarbon dated, revealed the sedimentation rates in different lagoonal environments and allowed the migration of two large meanders to be reconstructed. The average sedimentation rate of the study succession in the different sedimentary environments was 1.27 mm yr-1. The lateral migration rates were 13-23 m/century. This estimate is consistent with the lateral migration rates determined by comparing aerial photographs of recent channels. Comparing the buried channels with historical and current maps showed that, in general, the number of active channels is now reduced. Their morphology was sometimes simplified by artificial interventions. An understanding of the impact of the artificial interventions over time is useful for the management and conservation of tidal environments, particularly for the Lagoon of Venice, where management authorities are currently debating the possible deepening and rectification of large navigation channels.

  8. Advanced autumn migration of sparrowhawk has increased the predation risk of long-distance migrants in Finland.

    Directory of Open Access Journals (Sweden)

    Aleksi Lehikoinen

    Full Text Available Predation affects life history traits of nearly all organisms and the population consequences of predator avoidance are often larger than predation itself. Climate change has been shown to cause phenological changes. These changes are not necessarily similar between species and may cause mismatches between prey and predator. Eurasian sparrowhawk Accipiter nisus, the main predator of passerines, has advanced its autumn phenology by about ten days in 30 years due to climate change. However, we do not know if sparrowhawk migrate earlier in response to earlier migration by its prey or if earlier sparrowhawk migration results in changes to predation risk on its prey. By using the median departure date of 41 passerine species I was able to show that early migrating passerines tend to advance, and late migrating species delay their departure, but none of the species have advanced their departure times as much as the sparrowhawk. This has lead to a situation of increased predation risk on early migrating long-distance migrants (LDM and decreased the overlap of migration season with later departing short-distance migrants (SDM. Findings highlight the growing list of problems of declining LDM populations caused by climate change. On the other hand it seems that the autumn migration may become safer for SDM whose populations are growing. Results demonstrate that passerines show very conservative response in autumn phenology to climate change, and thus phenological mismatches caused by global warming are not necessarily increasing towards the higher trophic levels.

  9. Needle migration and dosimetric impact in high-dose-rate brachytherapy for prostate cancer evaluated by repeated MRI.

    Science.gov (United States)

    Buus, Simon; Lizondo, Maria; Hokland, Steffen; Rylander, Susanne; Pedersen, Erik M; Tanderup, Kari; Bentzen, Lise

    To quantify needle migration and dosimetric impact in high-dose-rate brachytherapy for prostate cancer and propose a threshold for needle migration. Twenty-four high-risk prostate cancer patients treated with an HDR boost of 2 × 8.5 Gy were included. Patients received an MRI for planning (MRI1), before (MRI2), and after treatment (MRI3). Time from needle insertion to MRI3 was ∼3 hours. Needle migration was evaluated from coregistered images: MRI1-MRI2 and MRI1-MRI3. Dose volume histogram parameters from the treatment plan based on MRI1 were related to parameters based on needle positions in MRI2 or MRI3. Regression was used to model the average needle migration per implant and change in D90 clinical target volume, CTV prostate+3mm . The model fit was used for estimating the dosimetric impact in equivalent dose in 2 Gy fractions for dose levels of 6, 8.5, 10, 15, and 19 Gy. Needle migration was on average 2.2 ± 1.8 mm SD from MRI1-MRI2 and 5.0 ± 3.0 mm SD from MRI1-MRI3. D90 CTV prostate+3mm was robust toward average needle migration ≤3 mm, whereas for migration >3 mm D90 decreased by 4.5% per mm. A 3 mm of needle migration resulted in a decrease of 0.9, 1.7, 2.3, 4.8, and 7.6 equivalent dose in 2 Gy fractions for dose levels of 6, 8.5, 10, 15, and 19 Gy, respectively. Substantial needle migration in high-dose-rate brachytherapy occurs frequently in 1-3 hours following needle insertion. A 3-mm threshold of needle migration is proposed, but 2 mm may be considered for dose levels ≥15 Gy. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  10. Effect of impurities on vacancy migration energy in Fe-based alloys

    International Nuclear Information System (INIS)

    Hashimoto, N.; Sakuraya, S.; Tanimoto, J.; Ohnuki, S.

    2014-01-01

    Effects of impurities, such as carbon, nitrogen, helium and hydrogen, on microstructural evolution in pure iron were investigated by means of a multi-beam electron microscope. Growth rate of dislocation loops were measured to calculate vacancy migration energies. In all irradiation temperature conditions, both the size and the number density of dislocation loops were increased as a function of dose. Irradiation with more impurities showed an increase in the temperature dependence of the dislocation loop growth rate compared to irradiation with little impurities. The in situ experiment indicated that the net migration energy of vacancies could be increased due to trapping by impurities, and the effect of C and N on the migration energy of vacancy would be larger than that of W, V, Ta. Furthermore, H and He would increase vacancy migration energy greater than C and N, as well as W, V, Ta. The density functional theory (DFT), applied to the atomic models of BCC iron, indicated an increase in vacancy migration energy by the trapping of impurity atoms, that is a good agreement with this in situ experiment

  11. 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

  12. 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.

  13. Men’s Migration and Women’s Fertility in Rural Mozambique

    OpenAIRE

    Agadjanian, Victor; Yabiku, Scott T.; Cau, Boaventura

    2011-01-01

    Labor migration profoundly affects households throughout rural Africa. This study looks at how men’s labor migration influences marital fertility in a context where such migration has been massive while its economic returns are increasingly uncertain. Using data from a survey of married women in southern Mozambique, we start with an event-history analysis of birth rates among women married to migrants and those married to nonmigrants. The model detects a lower birth rate among migrants’ wives...

  14. Bank Credit Risk Management and Rating Migration Analysis on the Business Cycle

    Directory of Open Access Journals (Sweden)

    Dimitris Gavalas

    2014-03-01

    Full Text Available Credit risk measurement remains a critical field of top priority in banking finance, directly implicated in the recent global financial crisis. This paper examines the dynamic linkages between credit risk migration due to rating shifts and prevailing macroeconomic conditions, reflected in alternative business cycle states. An innovative empirical methodology applies to bank internal rating data, under different economic scenarios and investigates the implications of credit risk quality shifts for risk rating transition matrices. The empirical findings are useful and critical for banks to align to Basel guidelines in relation to core capital requirements and risk-weighted assets in the underlying loan portfolio.

  15. Inhibition of the proliferation and acceleration of migration of vascular endothelial cells by increased cysteine-rich motor neuron 1

    International Nuclear Information System (INIS)

    Nakashima, Yukiko; Morimoto, Mayuka; Toda, Ken-ichi; Shinya, Tomohiro; Sato, Keizo; Takahashi, Satoru

    2015-01-01

    Cysteine-rich motor neuron 1 (CRIM1) is upregulated only in extracellular matrix gels by angiogenic factors such as vascular endothelial growth factor (VEGF). It then plays a critical role in the tube formation of endothelial cells. In the present study, we investigated the effects of increased CRIM1 on other endothelial functions such as proliferation and migration. Knock down of CRIM1 had no effect on VEGF-induced proliferation or migration of human umbilical vein endothelial cells (HUVECs), indicating that basal CRIM1 is not involved in the proliferation or migration of endothelial cells. Stable CRIM1-overexpressing endothelial F-2 cells, termed CR1 and CR2, were constructed, because it was difficult to prepare monolayer HUVECs that expressed high levels of CRIM1. Proliferation was reduced and migration was accelerated in both CR1 and CR2 cells, compared with normal F-2 cells. Furthermore, the transient overexpression of CRIM1 resulted in decreased proliferation and increased migration of bovine aortic endothelial cells. In contrast, neither proliferation nor migration of COS-7 cells were changed by the overexpression of CRIM1. These results demonstrate that increased CRIM1 reduces the proliferation and accelerates the migration of endothelial cells. These CRIM1 effects might contribute to tube formation of endothelial cells. CRIM1 induced by angiogenic factors may serve as a regulator in endothelial cells to switch from proliferating cells to morphological differentiation. - Highlights: • CRIM1 was upregulated only in tubular endothelial cells, but not in monolayers. • Increased CRIM1 reduced the proliferation of endothelial cells. • Increased CRIM1 accelerated the migration of endothelial cells. • Increased CRIM1 had no effect on the proliferation or migration of COS-7 cells

  16. Inhibition of the proliferation and acceleration of migration of vascular endothelial cells by increased cysteine-rich motor neuron 1

    Energy Technology Data Exchange (ETDEWEB)

    Nakashima, Yukiko; Morimoto, Mayuka [Department of Immunobiology, School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women' s University, 11-68 Koshien Kyuban-cho, Nishinomiya, Hyogo 663-8179 (Japan); Toda, Ken-ichi [Department of Dermatology, Kitano Hospital, The Tazuke Kofukai Nedical Institute, 2-4-20 Ohgimachi, Kita-ku, Osaka 530-8480 (Japan); Shinya, Tomohiro; Sato, Keizo [Department of Clinical Biochemistry, School of Pharmaceutical Sciences, Kyushu University of Health and Welfare, Nobeoka, Miyazaki 882-8508 (Japan); Takahashi, Satoru, E-mail: imwalrus@mukogawa-u.ac.jp [Department of Immunobiology, School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women' s University, 11-68 Koshien Kyuban-cho, Nishinomiya, Hyogo 663-8179 (Japan); Institute for Biosciences, Mukogawa Women' s University, 11-68 Koshien Kyuban-cho, Nishinomiya, Hyogo 663-8179 (Japan)

    2015-07-03

    Cysteine-rich motor neuron 1 (CRIM1) is upregulated only in extracellular matrix gels by angiogenic factors such as vascular endothelial growth factor (VEGF). It then plays a critical role in the tube formation of endothelial cells. In the present study, we investigated the effects of increased CRIM1 on other endothelial functions such as proliferation and migration. Knock down of CRIM1 had no effect on VEGF-induced proliferation or migration of human umbilical vein endothelial cells (HUVECs), indicating that basal CRIM1 is not involved in the proliferation or migration of endothelial cells. Stable CRIM1-overexpressing endothelial F-2 cells, termed CR1 and CR2, were constructed, because it was difficult to prepare monolayer HUVECs that expressed high levels of CRIM1. Proliferation was reduced and migration was accelerated in both CR1 and CR2 cells, compared with normal F-2 cells. Furthermore, the transient overexpression of CRIM1 resulted in decreased proliferation and increased migration of bovine aortic endothelial cells. In contrast, neither proliferation nor migration of COS-7 cells were changed by the overexpression of CRIM1. These results demonstrate that increased CRIM1 reduces the proliferation and accelerates the migration of endothelial cells. These CRIM1 effects might contribute to tube formation of endothelial cells. CRIM1 induced by angiogenic factors may serve as a regulator in endothelial cells to switch from proliferating cells to morphological differentiation. - Highlights: • CRIM1 was upregulated only in tubular endothelial cells, but not in monolayers. • Increased CRIM1 reduced the proliferation of endothelial cells. • Increased CRIM1 accelerated the migration of endothelial cells. • Increased CRIM1 had no effect on the proliferation or migration of COS-7 cells.

  17. Influence of infection rate and migration on extinction of disease in spatial epidemics

    NARCIS (Netherlands)

    Sun, G.Q.; Liu, Q.X.; Jin, Z.; Chakraborty, A.; Li, B.L.

    2010-01-01

    Extinction of disease can be explained by the patterns of epidemic spreading, yet the underlying causes of extinction are far from being well understood. To reveal a mechanism of disease extinction, a cellular automata model with both birth, death rate and migration is presented. We find that, in

  18. Rural to urban migration is associated with increased prevalence of childhood wheeze in a Latin-American city.

    Science.gov (United States)

    Rodriguez, Alejandro; Vaca, Maritza G; Chico, Martha E; Rodrigues, Laura C; Barreto, Mauricio L; Cooper, Philip J

    2017-01-01

    The urbanisation process has been associated with increases in asthma prevalence in urban and rural areas of low-income and middle-income countries (LMICs). However, although rural to urban migration and migration between cities are considered important determinants of this process, few studies have evaluated the effects of internal migration on asthma in urban populations of LMICs. The present study evaluated the effects of internal migration on the prevalence of wheeze in an urban area of Latin America. We did a cross-sectional analysis of 2510 schoolchildren living in the city of Esmeraldas, Ecuador. Logistic regression was used to analyse associations between childhood wheeze and different aspects of migration among schoolchildren. 31% of schoolchildren were migrants. Rural to urban migrants had a higher prevalence of wheeze, (adj.OR=2.01,95% CI1.30 to 3.01, p=0.001) compared with non-migrants. Age of migration and time since migration were associated with wheeze only for rural to urban migrants but not for urban to urban migrants. Children who had migrated after 3 years of age had a greater risk of wheeze (OR 2.51, 95% CI 1.56 to 3.97, p=0.001) than non-migrants while migrants with less than 5 years living in the new residence had a higher prevalence of wheeze than non-migrants (Latin-American city. Age of migration and time since migration were important determinants of wheeze only among migrants from rural areas. A better understanding of the social and environmental effects of internal migration could improve our understanding of the causes of the increase in asthma and differences in prevalence between urban and rural populations.

  19. Warming increases plant biomass and reduces diversity across continents, latitudes, and species migration scenarios in experimental wetland communities.

    Science.gov (United States)

    Baldwin, Andrew H; Jensen, Kai; Schönfeldt, Marisa

    2014-03-01

    Atmospheric warming may influence plant productivity and diversity and induce poleward migration of species, altering communities across latitudes. Complicating the picture is that communities from different continents deviate in evolutionary histories, which may modify responses to warming and migration. We used experimental wetland plant communities grown from seed banks as model systems to determine whether effects of warming on biomass production and species richness are consistent across continents, latitudes, and migration scenarios. We collected soil samples from each of three tidal freshwater marshes in estuaries at three latitudes (north, middle, south) on the Atlantic coasts of Europe and North America. In one experiment, we exposed soil seed bank communities from each latitude and continent to ambient and elevated (+2.8 °C) temperatures in the greenhouse. In a second experiment, soil samples were mixed either within each estuary (limited migration) or among estuaries from different latitudes in each continent (complete migration). Seed bank communities of these migration scenarios were also exposed to ambient and elevated temperatures and contrasted with a no-migration treatment. In the first experiment, warming overall increased biomass (+16%) and decreased species richness (-14%) across latitudes in Europe and North America. Species richness and evenness of south-latitude communities were less affected by warming than those of middle and north latitudes. In the second experiment, warming also stimulated biomass and lowered species richness. In addition, complete migration led to increased species richness (+60% in North America, + 100% in Europe), but this higher diversity did not translate into increased biomass. Species responded idiosyncratically to warming, but Lythrum salicaria and Bidens sp. increased significantly in response to warming in both continents. These results reveal for the first time consistent impacts of warming on biomass and

  20. The accretion of migrating giant planets

    Science.gov (United States)

    Dürmann, Christoph; Kley, Wilhelm

    2017-02-01

    Aims: Most studies concerning the growth and evolution of massive planets focus either on their accretion or their migration only. In this work we study both processes concurrently to investigate how they might mutually affect one another. Methods: We modeled a two-dimensional disk with a steady accretion flow onto the central star and embedded a Jupiter mass planet at 5.2 au. The disk is locally isothermal and viscosity is modeled using a constant α. The planet is held on a fixed orbit for a few hundred orbits to allow the disk to adapt and carve a gap. After this period, the planet is released and free to move according to the gravitational interaction with the gas disk. The mass accretion onto the planet is modeled by removing a fraction of gas from the inner Hill sphere, and the removed mass and momentum can be added to the planet. Results: Our results show that a fast migrating planet is able to accrete more gas than a slower migrating planet. Utilizing a tracer fluid we analyzed the origin of the accreted gas originating predominantly from the inner disk for a fast migrating planet. In the case of slower migration, the fraction of gas from the outer disk increases. We also found that even for very high accretion rates, in some cases gas crosses the planetary gap from the inner to the outer disk. Our simulations show that the crossing of gas changes during the migration process as the migration rate slows down. Therefore, classical type II migration where the planet migrates with the viscous drift rate and no gas crosses the gap is no general process but may only occur for special parameters and at a certain time during the orbital evolution of the planet.

  1. Freely-migrating defects: Their production and interaction with cascade remnants

    International Nuclear Information System (INIS)

    Rehn, L.E.; Wiedersich, H.

    1991-05-01

    Many microstructural changes that occur during irradiation are driven primarily by freely-migrating defects, i.e. those defects which escape from nascent cascades to migrate over distances that are large relative to typical cascade dimensions. Several measurements during irradiation at elevated temperatures have shown that the survival rate of freely-migrating defects decreases much more strongly with increasing primary recoil energy than does the survival rate for defects generated at liquid helium temperatures. For typical fission or fusion recoil spectra, and for heavy-ion bombardment, the fraction of defects that migrate long-distances is apparently only ∼1% of the calculated dpa. This small surviving fraction of freely-migrating defects results at least partially from additional intracascade recombination at elevated temperatures. However, cascade remnants, e.g., vacancy and interstitial clusters, also contribute by enhancing intercascade defect annihilation. A recently developed rate-theory approach is used to discuss the relative importance of intra- and intercascade recombination to the survival rate of freely-migrating defects. Within the validity of certain simplifying assumptions, the additional sink density provided by defect clusters produced directly within individual cascades can explain the difference between a defect survival rate of about 30% for low dose, low temperature irradiations with heavy ions, and a survival rate of only ∼1% for freely-migrating defects at elevated temperatures. The status of our current understanding of freely-migrating defects, including remaining unanswered questions, is also discussed. 33 refs., 5 figs

  2. Suppression of thymosin β10 increases cell migration and metastasis of cholangiocarcinoma

    International Nuclear Information System (INIS)

    Sribenja, Sirinapa; Sawanyawisuth, Kanlayanee; Kraiklang, Ratthaphol; Wongkham, Chaisiri; Vaeteewoottacharn, Kulthida; Obchoei, Sumalee; Yao, Qizhi; Wongkham, Sopit; Chen, Changyi

    2013-01-01

    Thymosin β10 (Tβ10) expression is associated with malignant phenotypes in many cancers. However, the role and mechanisms of Tβ10 in liver fluke-associated cholangiocarcinoma (CCA) are not fully understood. In this study, we investigated the expression of Tβ10 in CCA tumor tissues and cell lines as well as molecular mechanisms of Tβ10 in tumor metastasis of CCA cell lines. Tβ10 expression was determined by real time RT-PCR or immunocytochemistry. Tβ10 silence or overexpression in CCA cells was achieved using gene delivery techniques. Cell migration was assessed using modified Boyden chamber and wound healing assay. The effect of silencing Tβ10 on CCA tumor metastasis was determined in nude mice. Phosphorylation of ERK1/2 and the expression of EGR1, Snail and matrix metalloproteinases (MMPs) were studied. Ten pairs of CCA tissues (primary and metastatic tumors) and 5 CCA cell lines were studied. With real time RT-PCR and immunostaining analysis, Tβ10 was highly expressed in primary tumors of CCA; while it was relatively low in the metastatic tumors. Five CCA cell lines showed differential expression levels of Tβ10. Silence of Tβ10 significantly increased cell migration, invasion and wound healing of CCA cells in vitro; reversely, overexpression of Tβ10 reduced cell migration compared with control cells (P<0.05). In addition, silence of Tβ10 in CCA cells increased liver metastasis in a nude mouse model of CCA implantation into the spleen. Furthermore, silence of Tβ10 activated ERK1/2 and increased the expression of Snail and MMPs in CCA cell lines. Ras-GTPase inhibitor, FPT inhibitor III, effectively blocked Tβ10 silence-associated ERK1/2 activation, Snail expression and cell migration. Low expression of Tβ10 is associated with metastatic phenotype of CCA in vitro and in vivo, which may be mediated by the activation of Ras, ERK1/2 and upregulation of Snail and MMPs. This study suggests a new molecular pathway of CCA pathogenesis and a novel strategy to

  3. Simulation of vacancy migration energy in Cu under high strain

    International Nuclear Information System (INIS)

    Sato, K.; Yoshiie, T.; Satoh, Y.; Xu, Q.; Kiritani, M.

    2003-01-01

    The activation energy for the migration of vacancies in Cu under high strain was calculated by computer simulation using static methods. The migration energy of vacancies was 0.98 eV in the absence of deformation. It varied with the migration direction and stress direction because the distance between a vacancy and its neighboring atoms changes by deformation. For example, the migration energy for the shortest migration distance was reduced to 9.6 and 39.4% of its initial value by 10% compression and 20% elongation, respectively, while that for the longest migration distance was raised to 171.7 by 20% elongation. If many vacancies are created during high-speed deformation, the lowering of migration energy enables vacancies to escape to sinks such as surfaces, even during the shorter deformation period. The critical strain rate above which the strain rate dependence of vacancy accumulation ceases to exist increases with the lowering of vacancy migration energy

  4. Migration and Deforestation in Indonesia

    OpenAIRE

    Rivayani Darmawan; Stephan Klasen; Nunung Nuryartono

    2015-01-01

    Indonesia now has the highest deforestation rate in the world, with an average increase of about 47,600 ha per year. As a result, the nation is one of the largest emitters of greenhouse gases in the world and is putting its rich biodiversity at risk. Although the literature discussing the political economy of Indonesia commercial's logging is growing, only a small amount focuses on the relation-ship between migration and deforestation. Migration may contribute to the forest cover change, as m...

  5. The European Crisis and Migration to Germany: Expectations and the Diversion of Migration Flows

    OpenAIRE

    Brücker, Herbert; Bertoli, Simone; Fernández-Huertas Moraga, Jesús

    2013-01-01

    The European crisis has diverted migration flows away from countries affected by the recession towards Germany. The diversion process creates a challenge for traditional discrete-choice models that assume that only bilateral factors account for dyadic migration rates. This paper shows how taking into account the sequential nature of migration decisions leads to write the bilateral migration rate as a function of expectations about the evolution of economic conditions in alternative destinatio...

  6. Social integration prospectively predicts changes in heart rate variability among individuals undergoing migration stress.

    Science.gov (United States)

    Gouin, Jean-Philippe; Zhou, Biru; Fitzpatrick, Stephanie

    2015-04-01

    Poor social integration increases risk for poor health. The psychobiological pathways underlying this effect are not well-understood. This study utilized a migration stress model to prospectively investigate the impact of social integration on change in high-frequency heart rate variability (HF-HRV), a marker of autonomic functioning. Sixty new international students were recruited shortly after their arrival in the host country and assessed 2 and 5 months later. At each assessment period, participants provided information on social integration and loneliness and had their resting HF-HRV evaluated. There was an overall decrease in HF-HRV over time. The magnitude of the within-person and between-person effects of social integration on HRV increased over time, such that greater social integration was associated with higher HF-HRV at later follow-ups. These results suggest that altered autonomic functioning might represent a key pathway linking social integration to health outcomes.

  7. Migration, cultural bereavement and cultural identity

    OpenAIRE

    BHUGRA, DINESH; BECKER, MATTHEW A

    2005-01-01

    Migration has contributed to the richness in diversity of cultures, ethnicities and races in developed countries. Individuals who migrate experience multiple stresses that can impact their mental well being, including the loss of cultural norms, religious customs, and social support systems, adjustment to a new culture and changes in identity and concept of self. Indeed, the rates of mental illness are increased in some migrant groups. Mental health practitioners need to be ...

  8. Na+, HCO3--cotransporter NBCn1 increases pHi gradients, filopodia, and migration of smooth muscle cells and promotes arterial remodelling.

    Science.gov (United States)

    Boedtkjer, Ebbe; Bentzon, Jacob F; Dam, Vibeke S; Aalkjaer, Christian

    2016-08-01

    Arterial remodelling can cause luminal narrowing and obstruct blood flow. We tested the hypothesis that cellular acid-base transport facilitates proliferation and migration of vascular smooth muscle cells (VSMCs) and enhances remodelling of conduit arteries. [Formula: see text]-cotransport via NBCn1 (Slc4a7) mediates net acid extrusion and controls steady-state intracellular pH (pHi) in VSMCs of mouse carotid arteries and primary aortic explants. Carotid arteries undergo hypertrophic inward remodelling in response to partial or complete ligation in vivo, but the increase in media area and thickness and reduction in lumen diameter are attenuated in arteries from NBCn1 knock-out compared with wild-type mice. With [Formula: see text] present, gradients for pHi (∼0.2 units magnitude) exist along the axis of VSMC migration in primary explants from wild-type but not NBCn1 knock-out mice. Knock-out or pharmacological inhibition of NBCn1 also reduces filopodia and lowers initial rates of VSMC migration after scratch-wound infliction. Interventions to reduce H(+)-buffer mobility (omission of [Formula: see text] or inhibition of carbonic anhydrases) re-establish axial pHi gradients, filopodia, and migration rates in explants from NBCn1 knock-out mice. The omission of [Formula: see text] also lowers global pHi and inhibits proliferation in primary explants. Under physiological conditions (i.e. with [Formula: see text] present), NBCn1-mediated [Formula: see text] uptake raises VSMC pHi and promotes filopodia, VSMC migration, and hypertrophic inward remodelling. We propose that axial pHi gradients enhance VSMC migration whereas global acidification inhibits VSMC proliferation and media hypertrophy after carotid artery ligation. These findings support a key role of acid-base transport, particularly via NBCn1, for development of occlusive artery disease. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please

  9. The migration function and the Todaro paradox.

    Science.gov (United States)

    Takagi, Y

    1984-05-01

    "The purpose of this paper is to present a microeconomic foundation of the migration function and to discuss the impact of an increase in the job creation rate on migration and urban unemployment. Each rural worker must estimate his expected urban income on the basis of his own expected numbers of both newly created jobs and migrants during the coming period. Workers whose expected urban income is greater than the rural one decide to migrate, while those who estimate smaller urban income stay on." The geographical focus is on developing countries. excerpt

  10. The influence of the sorptive properties of organic soils on the migration rate of 137Cs

    International Nuclear Information System (INIS)

    Chibowski, S.; Zygmunt, J.

    2002-01-01

    Using a compartment model, the migration rates of 137 Cs were calculated for two types of organic soils: a low peat-muck soil and a black earth. The migration rates of 137 Cs in the tested soils turned out to be significantly higher than in mineral types examined earlier and ranged from 0.6 to 12.3 cm/year. The partition coefficients (K d ) were also determined for samples with varying organic matter content (OM) that were taken from different layers of the studied soils. The experimental results indicate that there is a clear relationship between K d values and OM. The investigation was widened by microcalorimetric measurements which confirmed that the adsorption of 137 Cs on the organic soils is low

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

    African Journals Online (AJOL)

    Ret:ieved 6 Octoher 1991; ut:cepted I8 Mur- 1995. 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 ...

  12. Is spatial mobility on the rise or in decline? An order-specific analysis of the migration of young adults in Sweden.

    Science.gov (United States)

    Kulu, Hill; Lundholm, Emma; Malmberg, Gunnar

    2018-04-17

    The aim of this study is to investigate spatial mobility over time. Research on 'new mobilities' suggests increasing movement of individuals, technology, and information. By contrast, studies of internal migration report declining spatial mobility in recent decades. Using longitudinal register data from Sweden, we calculate annual order-specific migration rates to investigate the spatial mobility of young adults over the last three decades. We standardize mobility rates for educational enrolment, educational level, family status, and place of residence to determine how much changes in individuals' life domains explain changes in mobility. Young adults' migration rates increased significantly in the 1990s; although all order-specific migration rates increased, first migration rates increased the most. Changes in population composition, particularly increased enrolment in higher education, accounted for much of the elevated spatial mobility in the 1990s. The analysis supports neither ever increasing mobility nor a long-term rise in rootedness among young adults in Sweden.

  13. Do Social Casino Gamers Migrate to Online Gambling? An Assessment of Migration Rate and Potential Predictors.

    Science.gov (United States)

    Kim, Hyoun S; Wohl, Michael J A; Salmon, Melissa M; Gupta, Rina; Derevensky, Jeffrey

    2015-12-01

    Social casino games (i.e., free-to-play online gambling games) are enjoyed by millions of players worldwide on a daily basis. Despite being free to play, social casino games share many similarities to traditional casino games. As such, concerns have been raised as to whether social casino games influences the migration to online gambling among people who have not engaged in such activity (see Griffiths in World Online Gambl 9:12-13, 2010). To date, however, no empirical research has assessed this possibility. Thus, the purpose of the present research was to assess the extent to which social casino gamers migrate to online gambling and potential predictors (time spent on social casino games, skill building, enhancement and micro-transactions) of such migration. To this end, social casino gamers who never gambled online (N = 409) completed a questionnaire battery assessing our variables of interest and were re-contacted 6-months later to see if they had engaged in online gambling during the intervening months. Approximately 26% of social casino gamers reported having migrated to online gambling. Importantly, engagement in micro-transactions was the only unique predictor of migration from social casino gaming to online gambling. The implications for the potential harms associated with social casino gaming are discussed.

  14. Urban bound migration and rural investment: the case of Mexico.

    Science.gov (United States)

    Silvers, A L; Crosson, P

    1983-02-01

    The authors investigate an agriculturally based policy for improving rural incomes and for retarding the rural-urban migration flow. The production of agricultural goods is characterized by a production function in which output increases with increases in agricultural labor inputs, capital, public infrastructure, land, and technology. Differences among regions in agricultural technology will reflect regional differences in education, the institutionalized form of productive organization, and differences in access to technological information channeled through more technically advanced cities. To pick up the effect of out-migration changes in state agricultural labor supply and upon agricultural output, the state's agricultural out-migration rate is included together with the agricultural labor force. The gross migrant flow between 2 locations is hypothesized to depend upon a set of variables influencing the individual's perception of the economic rate of return to be gained by moving, a set of variables reflecting the individual's propensity to relocate, the labor displacement effects of investments, and the at risk population at 1 location available to migrate. It is also taken into account that individuals differ in their response to information about origin and destination wage differentials and that individuals may or may not perceive a new ecnomic gain from migration but may base the decision on other considerations. Results of a statistical analysis using data from the Mexican census of population for 1960 and 1970 are: 1) size of the rural labor force was negatively associated with agricultural wages, contrary to expectations; 2) small farmers have benefited from the expansion of irrigation in Mexico; and 3) higher urban wages attract migration, and higher growth rate of agricultural income retards rural-urban migration. With respect to the 1950-60 decade both agricultural income and rural out-migration impacts could have been substantial but both the impact

  15. Shale gas activity and increased rates of sexually transmitted infections in Ohio, 2000-2016.

    Directory of Open Access Journals (Sweden)

    Nicole C Deziel

    Full Text Available The growing shale gas ("fracking" industry depends on a mobile workforce, whose influx could have social impacts on host communities. Sexually transmitted infections (STIs can increase through sexual mixing patterns associated with labor migration. No prior studies have quantified the relationship between shale gas activity and rates of three reportable STIs: chlamydia, gonorrhea, and syphilis.We conducted a longitudinal, ecologic study from 2000-2016 in Ohio, situated in a prolific shale gas region in the United States (US. Data on reported cases of chlamydia, gonorrhea, and syphilis by county and year were obtained from the Ohio Department of Health. All 88 counties were classified as none, low, and high shale gas activity in each year, using data from the Ohio Department of Natural Resources. Annual rate ratios (RR and 95% confidence intervals (95% CIs were calculated from mixed-effects Poisson regression models evaluating the relationship between shale gas activity and reported annual STI rates while adjusting for secular trends and potential confounders obtained from the US Census.Compared to counties with no shale gas activity, counties with high activity had 21% (RR = 1.21; 95%CI = 1.08-1.36 increased rates of chlamydia and 19% (RR = 1.27; 95%CI 0.98-1.44 increased rates of gonorrhea, respectively. No association was observed for syphilis.This first report of a link between shale gas activity and increased rates of both chlamydia and gonorrhea may inform local policies and community health efforts.

  16. High population increase rates.

    Science.gov (United States)

    1991-09-01

    In addition to its economic and ethnic difficulties, the USSR faces several pressing demographic problems, including high population increase rates in several of its constituent republics. It has now become clear that although the country's rigid centralized planning succeeded in covering the basic needs of people, it did not lead to welfare growth. Since the 1970s, the Soviet economy has remained sluggish, which as led to increase in the death and birth rates. Furthermore, the ideology that held that demography could be entirely controlled by the country's political and economic system is contradicted by current Soviet reality, which shows that religion and ethnicity also play a significant role in demographic dynamics. Currently, Soviet republics fall under 2 categories--areas with high or low natural population increase rates. Republics with low rates consist of Christian populations (Armenia, Moldavia, Georgia, Byelorussia, Russia, Lithuania, Estonia, Latvia, Ukraine), while republics with high rates are Muslim (Tadzhikistan, Uzbekistan, Turkmenistan, Kirgizia, Azerbaijan Kazakhstan). The later group has natural increase rates as high as 3.3%. Although the USSR as a whole is not considered a developing country, the later group of republics fit the description of the UNFPA's priority list. Another serious demographic issue facing the USSR is its extremely high rate of abortion. This is especially true in the republics of low birth rates, where up to 60% of all pregnancies are terminated by induced abortions. Up to 1/5 of the USSR's annual health care budget is spent on clinical abortions -- money which could be better spent on the production of contraceptives. Along with the recent political and economic changes, the USSR is now eager to deal with its demographic problems.

  17. Ecological advantages of partial migration as a conditional strategy.

    Science.gov (United States)

    Vélez-Espino, Luis A; McLaughlin, Robert L; Robillard, Melissa

    2013-05-01

    Partial migration is a widespread phenomenon characterized by migrant and resident forms from the same population. In phenotypically plastic taxa with indeterminate growth, resident and migrant ecophenotypes can differ in size and life history traits in ways expected to maximize fitness in the different habitats they exploit. Studies of partial migration in different taxa have advocated either density-dependence or environmental stochasticity as explanations for partial migration. We used a demographic approach for a virtual Brook Trout population to demonstrate the ecological consequences of partial migration under interacting density dependence and environmental stochasticity. The maintenance of partial migration as a conditional strategy in species/populations where resident and migrant forms exhibit life history asymmetries provides ecological advantages. We show that density-dependent migration is expected to increase population fitness under constant environmental conditions or low environmental variation, but decreases population fitness under high environmental variation. These conditions favor intermediate levels of migration as an advantageous tactic. However, there are threshold rates of return migration below which partial migration is no longer a viable tactic. Our modeling approach also allowed the exploration of the distribution of the population by life stage and habitat in response to the strength of density dependence, costs of migration, and return rates, and demonstrated the importance of the conservation of ecophenotypes in partially migratory populations. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Survival and progression rates of anadromous brown trout kelts Salmo trutta during downstream migration in freshwater and at sea

    DEFF Research Database (Denmark)

    Aarestrup, Kim; Baktoft, Henrik; Thorstad, EB

    2015-01-01

    The marine migration of post-spawning anadromous fish remains poorly understood. The present study examined survival and progression rates of anadromous brown trout Salmo trutta L. after spawning (kelts) during downriver, fjord, and sea migration. Kelts (n = 49) were captured in the Danish River...... completing the reach within 4 d, suggesting that the kelts spent limited time foraging after returning to the fjord. The total survival during the entire marine migration, including the fjord, was a minimum of 29%. Our study provides data that are important for management of anadromous brown trout...

  19. Migration decisions, agrarian structure, and gender: the case of Ecuador.

    Science.gov (United States)

    Bravo-ureta, B E; Quiroga, R E; Brea, J A

    1996-07-01

    This article briefly reviews the literature on migration in Latin America and examines migration decision making in Ecuador. Aggregate data are obtained from the 1974 census of agriculture and population for cantones. Individual level data are obtained from the 1982 census of population. Migration refers to all census persons who recorded differences in their present and previous place of residence during 1974-82. Migration is modeled as dependent upon gender, age, education, marital status, income at origin and at destination, and population pressure or agrarian reform. Logistic model findings indicate that migration decisions are influenced by individual characteristics of migrants and contextual variables. Migration varied by gender. The results confirm Todaro's hypothesis that the probability of migrating is related to income differences between place of destination and origin, but only for males. Findings suggest that females migrate for primary reasons other than economic ones. The probability of migration was greater with increased levels of education. The decision to migrate was affected by quality of life differences, such as literacy rates and levels of urbanization. The probability of migration was reduced by the effects of land reform. Population pressure had a significant effect in increasing migration. The effects of land reform differ from findings in Mexico by William E. Cole and Richard D. Sanders. Land reforms were initiated in 1964 in Ecuador, but by 1974 there was still considerable inequality in land distribution and increased population pressure. Traditional haciendas were modernized, and peasants increased their dependency on non-farm income.

  20. Silk Film Topography Directs Collective Epithelial Cell Migration

    Science.gov (United States)

    Rosenblatt, Mark I.

    2012-01-01

    The following study provides new insight into how surface topography dictates directed collective epithelial cell sheet growth through the guidance of individual cell movement. Collective cell behavior of migrating human corneal limbal-epithelial cell sheets were studied on highly biocompatible flat and micro-patterned silk film surfaces. The silk film edge topography guided the migratory direction of individual cells making up the collective epithelial sheet, which resulted in a 75% increase in total culture elongation. This was due to a 3-fold decrease in cell sheet migration rate efficiency for movement perpendicular to the topography edge. Individual cell migration direction is preferred in the parallel approach to the edge topography where localization of cytoskeletal proteins to the topography’s edge region is reduced, which results in the directed growth of the collective epithelial sheet. Findings indicate customized biomaterial surfaces may be created to direct both the migration rate and direction of tissue epithelialization. PMID:23185573

  1. Colloid migration in groundwaters: Geochemical interactions of radionuclides with natural colloids. Appendix III

    International Nuclear Information System (INIS)

    Wolf, M.; Geyer, S.; Fritz, P.; Klotz, D.; Lazik, D.

    1994-01-01

    The results obtained from the 152 Eu migration experiment in various columns packed with fine grained sand and equilibrated with a humic substance rich groundwater are: The retardation of mobile Eu-pseudocolloids (Eu-humate) is negligible, since the recovery is 152 Eu concentration is irreversible sorbed on the column, the degree of filtration expressed by the recovery is strongly dependant on the filtration velocity (flow rate): The recovery increases with increasing flow rates, indicating decreasing filtration, since the humic substances are negatively charged, the migration of the Eu pseudocolloids (humic colloids) is slightly accelerated relative to the migration of the 3 HHO tracer, due to anion repulsion. (orig.)

  2. Magnetic Field Fluctuations Due to Diel Vertical Migrations of Zooplankton

    Science.gov (United States)

    Dean, C.; Soloviev, A.

    2016-12-01

    Dean et al. (2016) have indicated that at high zooplankton concentrations, diel vertical migrations (DVM) cause velocity fluctuations and a respective increase of the dissipation rate of turbulent kinetic energy (TKE). In this work, we used a 3D non-hydrostatic computational fluid dynamics model with Lagrangian particle injections (a proxy for migrating organisms) via a discrete phase model to simulate the effect of turbulence generation by DVM. We tested a range of organism concentrations from 1000 to 10,000 organisms/m3. The simulation at an extreme concentration of zooplankton showed an increase in dissipation rate of TKE by two to three orders of magnitude during DVM over background turbulence, 10-8 W kg-1. At lower concentrations (Frank, J. Wood, 2016: Biomixing due to diel vertical migrations of zooplankton. Ocean Modelling 98, 51-64.

  3. Aryl hydrocarbon receptor–ligand axis mediates pulmonary fibroblast migration and differentiation through increased arachidonic acid metabolism

    International Nuclear Information System (INIS)

    Su, Hsiang-Han; Lin, Hsin-Ting; Suen, Jau-Ling; Sheu, Chau Chyun; Yokoyama, Kazunari K.; Huang, Shau-Ku; Cheng, Chih Mei

    2016-01-01

    Pulmonary fibroblast migration and differentiation are critical events in fibrogenesis; meanwhile, fibrosis characterizes the pathology of many respiratory diseases. The role of aryl hydrocarbon receptor (AhR), a unique cellular chemical sensor, has been suggested in tissue fibrosis, but the mechanisms through which the AhR-ligand axis influences the fibrotic process remain undefined. In this study, the potential impact of the AhR-ligand axis on pulmonary fibroblast migration and differentiation was analyzed using human primary lung fibroblasts HFL-1 and CCL-202 cells. Boyden chamber-based cell migration assay showed that activated AhR in HFL-1cells significantly enhanced cell migration in response to 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD), and a known AhR antagonist, CH223191, inhibited its migratory activity. Furthermore, the calcium mobilization and subsequent upregulated expression of arachidonic acid metabolizing enzymes, including cyclooxygenase2 (COX-2) and 5-lipoxygenase (5-LOX), were observed in TCDD-treated HFL-1 cells, concomitant with elevated levels of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) secretion. Also, significantly increased expression of α-smooth muscle actin α-SMA), a fibroblast differentiation marker, was also noted in TCDD-treated HFL-1 cells (p < 0.05), resulting in a dynamic change in cytoskeleton protein levels and an increase in the nuclear translocation of the myocardin-related transcription factor. Moreover, the enhanced levels of α-SMA expression and fibroblast migration induced by TCDD, PGE2 and LTB4 were abrogated by selective inhibitors for COX-2 and 5-LOX. Knockdown of AhR by siRNA Completely diminished intracellular calcium uptake and reduced α-SMA protein verified by promoter-reporter assays and chromatin immunoprecipitation. Taken together, our results suggested the importance of the AhR-ligand axis in fibroblast migration and differentiation through its capacity in enhancing arachidonic acid metabolism.

  4. International Migration, Management of Natural Resources and ...

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

    ... of Natural Resources and Division of Labour along Gender Lines in Veracruz, Mexico ... Mexico, are experiencing an increased rate of migration to Mexico City and the ... Linking research to urban planning at the ICLEI World Congress 2018.

  5. Effect of migration in a diffusion model for template coexistence in protocells.

    Science.gov (United States)

    Fontanari, José F; Serva, Maurizio

    2014-03-01

    The compartmentalization of distinct templates in protocells and the exchange of templates between them (migration) are key elements of a modern scenario for prebiotic evolution. Here we use the diffusion approximation of population genetics to study analytically the steady-state properties of such a prebiotic scenario. The coexistence of distinct template types inside a protocell is achieved by a selective pressure at the protocell level (group selection) favoring protocells with a mixed template composition. In the degenerate case, where the templates have the same replication rate, we find that a vanishingly small migration rate suffices to eliminate the segregation effect of random drift and so to promote coexistence. In the nondegenerate case, a small migration rate greatly boosts coexistence as compared with the situation where there is no migration. However, increase of the migration rate beyond a critical value leads to the complete dominance of the more efficient template type (homogeneous regime). In this case, we find a continuous phase transition separating the homogeneous and the coexistence regimes, with the order parameter vanishing linearly with the distance to the transition point.

  6. A preliminary assessment of gas diffusion and migration

    Energy Technology Data Exchange (ETDEWEB)

    Tanai, Kenji; Sato, Haruo [Waste Isolation Research Division, Tokai Works, Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan); Murakami, Tomohiro [Toyo Engineering Corp., Tokyo (Japan); Inoue, Masahiro [Kyushu Univ., Fukuoka (Japan)

    1999-11-01

    In the anaerobic environment in the deep underground water, carbon-steel overpack corrodes and generates molecular hydrogen. It is conceivable that this hydrogen either dissolves into the porewater of the buffer and migrates through the buffer. If the rate of aqueous diffusion of hydrogen is too low compared to the rate of hydrogen generation, the concentration of hydrogen at the overpack surface will increase until a solubility limit is attained and a free hydrogen gas phase forms. It is possible that the pressure in this accumulating gas phase will increase, affecting the stability of the buffer or the surrounding rock mass. There is also a concern of possible effects on nuclide migration, as it is also conceivable that the flow of gas could push out radionuclide-bearing porewater in the buffer when it floes through the buffer. As such, experimental and analytical study must be carried out on such phenomenon to evaluate such potential phenomena. (1) Diffusion experiment of dissolved hydrogen. (2) Gas permeability. (3) Evaluation of diffusion of dissolved hydrogen and hydrogen gas migration. (J.P.N.)

  7. Eliciting illegal migration rates through list randomization

    NARCIS (Netherlands)

    McKenzie, D.; Siegel, M.

    2013-01-01

    Most migration surveys do not ask about the legal status of migrants due to concerns about the sensitivity of this question. List randomization is a technique that has been used in a number of other social science applications to elicit sensitive information. We trial this technique by adding it to

  8. Modification of meander migration by bank failures

    Science.gov (United States)

    Motta, D.; Langendoen, E. J.; Abad, J. D.; García, M. H.

    2014-05-01

    Meander migration and planform evolution depend on the resistance to erosion of the floodplain materials. To date, research to quantify meandering river adjustment has largely focused on resistance to erosion properties that vary horizontally. This paper evaluates the combined effect of horizontal and vertical floodplain material heterogeneity on meander migration by simulating fluvial erosion and cantilever and planar bank mass failure processes responsible for bank retreat. The impact of stream bank failures on meander migration is conceptualized in our RVR Meander model through a bank armoring factor associated with the dynamics of slump blocks produced by cantilever and planar failures. Simulation periods smaller than the time to cutoff are considered, such that all planform complexity is caused by bank erosion processes and floodplain heterogeneity and not by cutoff dynamics. Cantilever failure continuously affects meander migration, because it is primarily controlled by the fluvial erosion at the bank toe. Hence, it impacts migration rates and meander shapes through the horizontal and vertical distribution of erodibility of floodplain materials. Planar failures are more episodic. However, in floodplain areas characterized by less cohesive materials, they can affect meander evolution in a sustained way and produce preferential migration patterns. Model results show that besides the hydrodynamics, bed morphology and horizontal floodplain heterogeneity, floodplain stratigraphy can significantly affect meander evolution, both in terms of migration rates and planform shapes. Specifically, downstream meander migration can either increase or decrease with respect to the case of a homogeneous floodplain; lateral migration generally decreases as result of bank protection due to slump blocks; and the effect on bend skewness depends on the location and volumes of failed bank material caused by cantilever and planar failures along the bends, with possible achievement of

  9. Migration of ThO2 kernels under the influence of a temperature gradient

    International Nuclear Information System (INIS)

    Smith, C.L.

    1976-11-01

    BISO coated ThO 2 fertile fuel kernels will migrate up the thermal gradients imposed across coated particles during HTGR operation. Thorium dioxide kernel migration has been studied as a function of temperature (1300 to 1700 0 C) and ThO 2 kernel burnup (0.9 to 5.8 percent FIMA) in out-of-pile, postirradiation thermal gradient heating experiments. The studies were conducted to obtain descriptions of migration rates that will be used in core design studies to evaluate the impact of ThO 2 migration on fertile fuel performance in an operating HTGR and to define characteristics needed by any comprehensive model describing ThO 2 kernel migration. The kinetics data generated in these postirradiation studies are consistent with in-pile data collected by investigators at Oak Ridge National Laboratory, which supports use of the more precise postirradiation heating results in HTGR core design studies. Observations of intergranular carbon deposits on the cool side of migrating kernels support the assumption that the kinetics of kernel migration are controlled by solid state diffusion within irradiated ThO 2 kernels. The migration is characterized by a period of no migration (incubation period) followed by migration at the equilibrium rate for ThO 2 . The incubation period decreases with increasing temperature and kernel burnup. The improved understanding of the kinetics of ThO 2 kernel migration provided by this work will contribute to an optimization of HTGR core design and an increased confidence in fuel performance predictions

  10. Effect of Ingredient Loading on Surface Migration Kinetics of Additives in Vulcanized Natural Rubber Compounds

    Directory of Open Access Journals (Sweden)

    Bryan B. Pajarito

    2014-12-01

    Full Text Available Surface migration kinetics of chemical additives in vulcanized natural rubber compounds were studied as function of ingredient loading. Rubber sheets were compounded according to a 212-8 fractional factorial design of experiment, where ingredients were treated as factors varied at two levels of loading. Amount of migrated additives in surface of rubber sheets was monitored through time at ambient conditions. The maximum amount and estimated rate of additive migration were determined from weight loss kinetic curves. Attenuated total reflection–Fourier transform infrared (ATR-FTIR spectroscopy and optical microscopy were used to characterize the chemical structure and surface morphology of sheet specimens during additive migration. ANOVA results showed that increased loading of reclaimed rubber, CaCO3, and paraffin wax signif icantly decreased the maximum amount of additive migration; by contrast, increased loading of used oil, asphalt, and mercaptobenzothiazole disulphide (MBTS increased the maximum amount. Increased loading of sulfur, diphenylguanidine (DPG, and paraffin wax significantly decreased the additive migration rate; increased loading of used oil, asphalt, and stearic acid elicited an opposite effect. Comparison of ATRFTIR spectra of migrated and cleaned rubber surfaces showed signif icant variation in intensity of specif ic absorbance bands that are also present in infrared spectra of migrating chemicals. Paraffin wax, used oil, stearic acid, MBTS, asphalt, and zinc stearate were identified to bloom and bleed in the rubber sheets. Optical micrographs of migrated rubber surfaces revealed formation of white precipitates due to blooming and of semi-transparent wet patches due to bleeding.

  11. MIGRATION OF PLANETS EMBEDDED IN A CIRCUMSTELLAR DISK

    International Nuclear Information System (INIS)

    Bromley, Benjamin C.; Kenyon, Scott J.

    2011-01-01

    Planetary migration poses a serious challenge to theories of planet formation. In gaseous and planetesimal disks, migration can remove planets as quickly as they form. To explore migration in a planetesimal disk, we combine analytic and numerical approaches. After deriving general analytic migration rates for isolated planets, we use N-body simulations to confirm these results for fast and slow migration modes. Migration rates scale as m -1 (for massive planets) and (1 + (e H /3) 3 ) -1 , where m is the mass of a planet and e H is the eccentricity of the background planetesimals in Hill units. When multiple planets stir the disk, our simulations yield the new result that large-scale migration ceases. Thus, growing planets do not migrate through planetesimal disks. To extend these results to migration in gaseous disks, we compare physical interactions and rates. Although migration through a gaseous disk is an important issue for the formation of gas giants, we conclude that migration has little impact on the formation of terrestrial planets.

  12. Luminal and basal-like breast cancer cells show increased migration induced by hypoxia, mediated by an autocrine mechanism

    International Nuclear Information System (INIS)

    Voss, Melanie J; Möller, Mischa F; Powe, Desmond G; Niggemann, Bernd; Zänker, Kurt S; Entschladen, Frank

    2011-01-01

    Some breast cancer patients receiving anti-angiogenic treatment show increased metastases, possibly as a result of induced hypoxia. The effect of hypoxia on tumor cell migration was assessed in selected luminal, post-EMT and basal-like breast carcinoma cell lines. Migration was assessed in luminal (MCF-7), post-EMT (MDA-MB-231, MDA-MB-435S), and basal-like (MDA-MB-468) human breast carcinoma cell lines under normal and oxygen-deprived conditions, using a collagen-based assay. Cell proliferation was determined, secreted cytokine and chemokine levels were measured using flow-cytometry and a bead-based immunoassay, and the hypoxic genes HIF-1α and CA IX were assessed using PCR. The functional effect of tumor-cell conditioned medium on the migration of neutrophil granulocytes (NG) was tested. Hypoxia caused increased migratory activity but not proliferation in all tumor cell lines, involving the release and autocrine action of soluble mediators. Conditioned medium (CM) from hypoxic cells induced migration in normoxic cells. Hypoxia changed the profile of released inflammatory mediators according to cell type. Interleukin-8 was produced only by post-EMT and basal-like cell lines, regardless of hypoxia. MCP-1 was produced by MDA-MB-435 and -468 cells, whereas IL-6 was present only in MDA-MB-231. IL-2, TNF-α, and NGF production was stimulated by hypoxia in MCF-7 cells. CM from normoxic and hypoxic MDA-MB-231 and MDA-MB-435S cells and hypoxic MCF-7 cells, but not MDA-MB-468, induced NG migration. Hypoxia increases migration by the autocrine action of released signal substances in selected luminal and basal-like breast carcinoma cell lines which might explain why anti-angiogenic treatment can worsen clinical outcome in some patients

  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. Moving across boundaries: migration in South Africa, 1950-2000.

    Science.gov (United States)

    Reed, Holly E

    2013-02-01

    Existing knowledge about historical patterns of black internal migration in South Africa is incomplete, primarily because of the lack of good life course studies as well as the apartheid government's suppression and censoring of data. This article provides a comprehensive picture of historical internal migration patterns with an analysis of a unique individual retrospective life history data set. This sample of the black population, collected in 2000, is the only known nationally representative life history data for South Africa; it includes all residential moves for each individual during his/her lifetime. Various mobility outcomes are analyzed: moves within/across provinces, moves within/across rural and urban areas, forced moves, moves with a nuclear family, and individual moves. The results indicate that migration significantly increased among black South Africans during the last half of the twentieth century, and that this increase began before the Pass Laws were repealed in 1986 and well before the official end of apartheid in 1991 or the first free election in 1994. The timing of this increase in migration rates suggests that migration in defiance of the Pass Laws (albeit a dangerous and desperate proposition) was a way of life for many black South Africans.

  15. Migration-driven aggregation behaviors in job markets with direct foreign immigration

    International Nuclear Information System (INIS)

    Sun, Ruoyan

    2014-01-01

    This Letter introduces a new set of rate equations describing migration-driven aggregation behaviors in job markets with direct foreign immigration. We divide the job market into two groups: native and immigrant. A reversible migration of jobs exists in both groups. The interaction between two groups creates a birth and death rate for the native job market. We find out that regardless of initial conditions or the rates, the total number of cities with either job markets decreases. This indicates a more concentrated job markets for both groups in the future. On the other hand, jobs available for immigrants increase over time but the ones for natives are uncertain. The native job markets can either expand or shrink or remain constant due to combined effects of birth and death rates. Finally, we test our analytical results with the population data of all counties in the US from 2000 to 2011. - Highlights: • A rate equation model describing the migration of job market is proposed. • We study the migration-driven aggregation behaviors over the longer term. • An illustrative example is given to check the effectiveness of the model

  16. Migration-driven aggregation behaviors in job markets with direct foreign immigration

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Ruoyan

    2014-09-05

    This Letter introduces a new set of rate equations describing migration-driven aggregation behaviors in job markets with direct foreign immigration. We divide the job market into two groups: native and immigrant. A reversible migration of jobs exists in both groups. The interaction between two groups creates a birth and death rate for the native job market. We find out that regardless of initial conditions or the rates, the total number of cities with either job markets decreases. This indicates a more concentrated job markets for both groups in the future. On the other hand, jobs available for immigrants increase over time but the ones for natives are uncertain. The native job markets can either expand or shrink or remain constant due to combined effects of birth and death rates. Finally, we test our analytical results with the population data of all counties in the US from 2000 to 2011. - Highlights: • A rate equation model describing the migration of job market is proposed. • We study the migration-driven aggregation behaviors over the longer term. • An illustrative example is given to check the effectiveness of the model.

  17. Production of freely-migrating defects during irradiation

    International Nuclear Information System (INIS)

    Rehn, L.E.; Okamoto, P.R.

    1986-09-01

    During irradiation at elevated temperatures, vacancy and interstitial defects that escape can produce several different types of microstructural changes. Hence the production rate of freely-migrating defects must be known as a function of irradiating particle species and energy before quantitative correlations can be made between microstructural changes. Our fundamental knowledge of freely-migrating defect production has increased substantially in recent years. Critical experimental findings that led to the improved understanding are reviewed in this paper. A strong similarity is found for the dependence of freely-migrating defect production on primary recoil energy as measured in a variety of metals and alloys by different authors. The efficiency for producing freely-migrating defects decreases much more strongly with increasing primary recoil energy than does the efficiency for creating stable defects at liquid helium temperatures. The stronger decrease can be understood in terms of additional intracascade recombination that results from the nonrandom distribution of defects existing in the primary damage state for high primary recoil energies. Although the existing data base is limited to fcc materials, the strong similarity in the reported investigations suggests that the same dependence of freely-migrating defect production on primary recoil energy may be characteristic of a wide variety of other alloy systems as well. 52 refs., 4 figs

  18. Correlation of rates of tritium migration through porous concrete

    Energy Technology Data Exchange (ETDEWEB)

    Fukada, S.; Katayama, K.; Takeishi, T. [Kyushu University, Fukuoka (Japan); Edao, Y.; Kawamura, Y.; Hayashi, T.; Yamanishi, T. [JAEA-TPL, Muramatsu, Tokai-mura (Japan)

    2015-03-15

    In a nuclear facility when tritium leaks from a glovebox to room accidentally, an atmosphere detritiation system (ADS) starts operating, and HTO released is recovered by ADS. ADS starts when tritium activity in air becomes higher than its controlled level. Before ADS operates, the laboratory walls are the final enclosure facing tritium and are usually made of porous concrete coated with a hydrophobic paint. In the present study, previous data on the diffusivity and adsorption coefficient of concrete and paints are reviewed. Tritium penetrates and migrates into concrete by following 3 ways. First, gaseous HT or T{sub 2} easily penetrates into porous concrete. Its diffusivity is almost equal to that of H{sub 2}. When a gaseous molecule diffuses through pores with a smaller diameter than a mean free path, its migration rate is described by the Knudsen diffusion formula. The second mechanism is H{sub 2}O vapor diffusion in pores. Concrete holds a lot of structural water. Therefore, H{sub 2}O or HTO vapor can diffuse inside concrete pores along with adsorption-desorption and isotopic exchange with structural water, which is the third mechanism. Literature shows that the diffusivity of HTO through the epoxy-resin paint is determined as D(HTO)=1.0*10{sup -16} m{sup 2}/s. We have used this data to set a model and we have applied it to estimate residual tritium in laboratory walls. We have considered 2 accidental cases and a normal case: first, ADS starts operating 1 hour after 100 Ci HTO is released in the room, secondly, ADS starts 24 hours after 100 Ci HTO release and thirdly, when the walls are exposed to HTO for 10 years of normal operation. It appears that the immediate start up of ADS is indispensable for safety.

  19. The Stent Patency and Migration Rate of Different Shaped Plastic Stents in Bile Flow Phantom Model and In Vivo Animal Bile Duct Dilation Model.

    Science.gov (United States)

    Kwon, Chang-Il; Kim, Gwangil; Jeong, Seok; Lee, Don Haeng; Kim, Kyoung Ah; Ko, Kwang Hyun; Cho, Joo Young; Hong, Sung Pyo

    2017-05-01

    In research and development of biliary plastic stents (PS), continuous efforts have been made to overcome short patency time and high rate of migration. The aim of this study was to evaluate the patency and migration rate of different PS shapes for a given period of time. Using an in vitro bile phantom model, we compared the patency among different shapes of PS (three straight PS, four double-pigtail PS, and a new screw-shaped PS). We performed an analysis of the degree of luminal narrowing by light microscopic examination. Using an in vivo swine model, we compared the patency and migration rate among the three different types of PS. Eight weeks after the bile exposure in the bile flow phantom model, 80 PS were retrieved and analyzed. The straight PS showed less biofilm formation and luminal narrowing than other types of PS (p stent migration occurred less frequently in the double-pigtail PS and the screw-shaped PS than it did in the straight PS (11.1, 10, and 27.3%, respectively). However, there was no statistical difference in stent patency among the different shapes. Stent patency may not be significantly different depending on the shape of PS for 8 weeks. The screw-shaped PS showed similar patency and migration rate to the double-pigtail PS. These results may help guiding future PS development and clinical decisions.

  20. Shale gas activity and increased rates of sexually transmitted infections in Ohio, 2000–2016

    Science.gov (United States)

    Humeau, Zoe; Elliott, Elise G.; Warren, Joshua L.; Niccolai, Linda M.

    2018-01-01

    Background The growing shale gas (“fracking”) industry depends on a mobile workforce, whose influx could have social impacts on host communities. Sexually transmitted infections (STIs) can increase through sexual mixing patterns associated with labor migration. No prior studies have quantified the relationship between shale gas activity and rates of three reportable STIs: chlamydia, gonorrhea, and syphilis. Methods We conducted a longitudinal, ecologic study from 2000–2016 in Ohio, situated in a prolific shale gas region in the United States (US). Data on reported cases of chlamydia, gonorrhea, and syphilis by county and year were obtained from the Ohio Department of Health. All 88 counties were classified as none, low, and high shale gas activity in each year, using data from the Ohio Department of Natural Resources. Annual rate ratios (RR) and 95% confidence intervals (95% CIs) were calculated from mixed-effects Poisson regression models evaluating the relationship between shale gas activity and reported annual STI rates while adjusting for secular trends and potential confounders obtained from the US Census. Results Compared to counties with no shale gas activity, counties with high activity had 21% (RR = 1.21; 95%CI = 1.08–1.36) increased rates of chlamydia and 19% (RR = 1.27; 95%CI 0.98–1.44) increased rates of gonorrhea, respectively. No association was observed for syphilis. Conclusion This first report of a link between shale gas activity and increased rates of both chlamydia and gonorrhea may inform local policies and community health efforts. PMID:29570712

  1. A personality theory of U.S. migration geography.

    Science.gov (United States)

    Stetzer, F C

    1985-01-01

    "Neoclassical models of migration fail to account adequately for individual differences in propensity to migrate, rates of emigration from states and cities, and the generally high rates of population circulation common in the United States. This article proposes that migration propensity is related to an individual's personality. Using the facts that personality traits are generationally regenerative, both through inheritance and culture, and that the United States was settled in a series of migration waves from east to west, this theory predicts a spatial structuring of emigration rates which closely correspond to actual rates for states and major cities." excerpt

  2. Y-27632 Increases Sensitivity of PANC-1 Cells to EGCG in Regulating Cell Proliferation and Migration.

    Science.gov (United States)

    Liu, Xing; Bi, Yongyi

    2016-10-03

    BACKGROUND The study aimed to investigate the inhibitory effect of (1R,4r)-4-((R)-1-aminoethyl)-N-(pyridin-4-yl) cyclohexanecarboxamide (Y-27632) and (-)-epigallocatechin-3-gallate (EGCG) on the proliferation and migration of PANC-1 cells. EGCG, found in green tea, has been previously shown to be one of the most abundant and powerful catechins in cancer prevention and treatment. Y-27632, a selective inhibitor of rho-associated protein kinase 1, is widely used in treating cardiovascular disease, inflammation, and cancer. MATERIAL AND METHODS PANC-1 cells, maintained in Dulbecco's Modified Eagle's Medium, were treated with dimethyl sulfoxide (control) as well as different concentrations (20, 40, 60, and 80 μg/mL) of EGCG for 48 h. In addition, PANC-1 cells were treated separately with 60 μg/mL EGCG, 20 μM Y-27632, and EGCG combined with Y-27632 (60 μg/mL EGCG + 20 μM Y-27632) for 48 h. The effect of EGCG and Y-27632 on the proliferation and migration of PANC-1 cells was evaluated using Cell Counting Kit-8 and transwell migration assays. The expression of peroxisome proliferator-activated receptor alpha (PPARα) and Caspase-3 mRNA was determined by Quantitative real-time polymerase chain reaction (RT-qPCR). RESULTS EGCG (20-80 μg/mL) inhibited cell viability in a dose-dependent manner. Y-27632 enhanced the sensitivity of PANC-1 cells to EGCG (by increasing the expression of PPARa and Caspase-3 mRNA) and suppressed cell proliferation. PANC-1 cell migration was inhibited by treatment with a combination of EGCG and Y-27632. CONCLUSIONS Y-27632 increases the sensitivity of PANC-1 cells to EGCG in regulating cell proliferation and migration, which is likely to be related to the expression of PPARa mRNA and Caspase-3 mRNA.

  3. Effects of growth rate on structural property and adatom migration behaviors for growth of GaInNAs/GaAs (001) by molecular beam epitaxy

    Science.gov (United States)

    Li, Jingling; Gao, Peng; Zhang, Shuguang; Wen, Lei; Gao, Fangliang; Li, Guoqiang

    2018-03-01

    We have investigated the structural properties and the growth mode of GaInNAs films prepared at different growth rates (Rg) by molecular beam epitaxy. The crystalline structure is studied by high resolution X-ray diffraction, and the evolution of GaInNAs film surface morphologies is studied by atomic force microscopy. It is found that both the crystallinity and the surface roughness are improved by increasing Rg, and the change in the growth mode is attributed to the adatom migration behaviors particularly for In atoms, which is verified by elemental analysis. In addition, we have presented some theoretical calculation results related to the N adsorption energy to show the unique N migration behavior, which is instructive to interpret the growth mechanism of GaInNAs films.

  4. Compulsory Schooling Laws and Migration Across European Countries.

    Science.gov (United States)

    Aparicio Fenoll, Ainhoa; Kuehn, Zoë

    2017-12-01

    Educational attainment is a key factor for understanding why some individuals migrate and others do not. Compulsory schooling laws, which determine an individual's minimum level of education, can potentially affect migration. We test whether and how increasing the length of compulsory schooling influences migration of affected cohorts across European countries, a context where labor mobility is essentially free. We construct a novel database that includes information for 31 European countries on compulsory education reforms passed between 1950 and 1990. Combining this data with information on recent migration flows by cohorts, we find that an additional year of compulsory education reduces the number of individuals from affected cohorts who migrate in a given year by 9 %. Our results rely on the exogeneity of compulsory schooling laws. A variety of empirical tests indicate that European legislators did not pass compulsory education reforms as a reaction to changes in emigration rates or educational attainment.

  5. Regulators of Intestinal Epithelial Migration in Sepsis.

    Science.gov (United States)

    Meng, Mei; Klingensmith, Nathan J; Liang, Zhe; Lyons, John D; Fay, Katherine T; Chen, Ching-Wen; Ford, Mandy L; Coopersmith, Craig M

    2018-02-08

    The gut is a continuously renewing organ, with cell proliferation, migration and death occurring rapidly under basal conditions. Since the impact of critical illness on cell movement from crypt base to villus tip is poorly understood, the purpose of this study was to determine how sepsis alters enterocyte migration. Wild type, transgenic and knockout mice were injected with 5-bromo-2'deoxyuridine (BrdU) to label cells in S phase before and after the onset of cecal ligation and puncture and were sacrificed at pre-determined endpoints to determine distance proliferating cells migrated up the crypt-villus unit. Enterocyte migration rate was decreased from 24-96 hours following sepsis. BrdU was not detectable on villi 6 days after sham laparotomy, meaning all cells had migrated the length of the gut and been exfoliated into its lumen. However, BrdU positive cells were detectable on villi 10 days after sepsis. Multiple components of gut integrity altered enterocyte migration. Sepsis decreased crypt proliferation, which further slowed enterocyte transit as mice injected with BrdU after the onset of sepsis (decreased proliferation) had slower migration than mice injected with BrdU prior to the onset of sepsis (normal proliferation). Decreasing intestinal apoptosis via gut-specific overexpression of Bcl-2 prevented sepsis-induced slowing of enterocyte migration. In contrast, worsened intestinal hyperpermeability by genetic deletion of JAM-A increased enterocyte migration. Sepsis therefore significantly slows enterocyte migration, and intestinal proliferation, apoptosis and permeability all affect migration time, which can potentially be targeted both genetically and pharmacologically.

  6. Labour migration from Turkey.

    Science.gov (United States)

    Uner, S

    1988-01-01

    This study is concerned with Turkish labor migration to Western Europe. Earlier and recent patterns of labor migration, characteristics of migrants by occupation, area of destination, and by geographical origins are discussed. Economic and demographic consequences of labor migration are also analyzed. It is estimated that Turkey's population will reach 73 million at the year 2000 with the present growth rate of 2.48% annually. Considering the efforts made to slow down the present high fertility rates and assuming that the decrease in labor force participation during 1970-1980 continues, the author concludes that the labor supply will increase with a growth rate of 2% annually for the next 13-15 years. Thus, the labor supply will reach 26.6 million people in the year 2000 from the 1980 level of 17.8 million. Assuming also that the income/employment elasticity of .25 which was observed throughout the period of 1960-1980 will not change until 2000, the annual growth rate of employment may be estimated as 1.5%. Thus, the number of people employed will reach 20 million in the year 1990 and 23.2 million in the year 2000. 8.8 million people will join the labor market as new entrants between 1980 and 2000. Only 6 million people out of 8.8 million will be employed. Thus, in the year 2000, it is estimated that 2.8 million new unemployed people will be added to the already open unemployment figure 1980 census data give the number of unemployed as .6 million people. Adding the 2.8 million new unemployed to this figure totals 3.4 million unemployed in 2000. The State Planning Organization's estimate of labor surplus for 1980 was 2.5 million people. When 2.8 million unemployed people are added to this figure, the labor surplus for the year 2000 reaches 5.3 million people.

  7. Does Access to Foreign Markets shape Internal Migration? Evidence from Brazil

    OpenAIRE

    Laura Hering; Rodrigo Paillacar

    2014-01-01

    This paper investigates how internal migration is affected by Brazil’s increased integration into the world economy. It analyzes the impact of regional differences in access to foreign demand on sector-specific bilateral migration rates between the Brazilian states for the years 1995 to 2003. Using international trade data, a foreign market access measure is computed at the sectoral level,...

  8. The paradox of Spoonbill migration : Most birds travel to where survival rates are lowest

    NARCIS (Netherlands)

    Lok, Tamar; Overdijk, Otto; Tinbergen, Joost M.; Piersma, Theunis

    2011-01-01

    Migrant birds face a choice where to spend the winter. Presumably there is a trade-off between migration distance (costs) and the quality of the wintering site (benefits). Wintering site fidelity is often high and increases with age. Hypotheses to explain such a pattern assume that wintering site

  9. Migration of the ThO2 kernels under the influence of a temperature gradient

    International Nuclear Information System (INIS)

    Smith, C.L.

    1977-01-01

    Biso-coated ThO 2 fertile fuel kernels will migrate up the thermal gradients imposed across coated particles during high-temperature gas-cooled reactor (HTGR) operation. Thorium dioxide kernel migration has been studied as a function of temperature (1290 to 1705 0 C) (1563 to 1978 K) and ThO 2 kernel burnup (0.9 to 5.8 percent FIMA) in out-of-pile postirradiation thermal gradient heating experiments. The studies were conducted to obtain descriptions of migration rates that will be used in core design studies to evaluate the impact of ThO 2 migration on fertile fuel performance in an operating HTGR and to define characteristics needed by any comprehensive model describing ThO 2 kernel migration. The kinetics data generated in these postirradiation studies are consistent with in-pile data collected by investigators at Oak Ridge National Laboratory, which supports use of the more precise postirradiation heating results in HTGR core design studies. Observations of intergranular carbon deposits on the cool side of migrating kernels support the assumption that the kinetics of kernel migration are controlled by solid-state diffusion within irradiated ThO 2 kernels. The migration is characterized by a period of no migration (incubation period), followed by migration at the equilibrium rate for ThO 2 . The incubation period decreases with increasing temperature and kernel burnup. The improved understanding of the kinetics of ThO 2 kernel migration provided by this work will contribute to an optimization of HTGR core design and an increased confidence in fuel performance predictions

  10. A novel, ring-connected stent versus conventional GI stents: comparative study of physical properties and migration rates in a canine colon obstruction model.

    Science.gov (United States)

    Park, Hong Suk; Choo, In Wook; Seo, Soowon; Hyun, Dongho; Lim, Sooyoun; Kim, Jae J; Hong, Saet-Byul; Min, Byung-Hoon; Do, Young Soo; Choo, Sung Wook; Shin, Sung Wook; Park, Kwang Bo; Cho, Sung Ki

    2015-01-01

    Migration of stents is one of the most common adverse events in covered stent placement in GI tract obstruction. To compare physical property and migration rates in a canine colon obstruction model among a novel stent and conventional stents. Comparative physical test and animal study. Medical device testing laboratory and animal laboratory. Mongrel dogs (N=26). Surgical colon obstruction followed by placement of a novel (n=13) or conventional (n=13) stent. Physical properties, migration, and adverse events. The novel stent showed better flexibility, as in a physical test of longitudinal compressibility and axial force, than did conventional stents, and it withstood the fatigue test for 10 days. In terms of radial force and tensile strength, the novel stent showed the same or better results than conventional stents. In a canine colon obstruction model, the migration rate of a novel stent was significantly lower than that of a conventional stent (2/13, 15.4% vs 8/13, 61.5%; P=.008). Animal study of limited size. The novel, ring-connected stent is more flexible and more resistant to migration than the conventional stents. Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

  11. The role of the antioxidant system during intense endurance exercise: lessons from migrating birds.

    Science.gov (United States)

    Cooper-Mullin, Clara; McWilliams, Scott R

    2016-12-01

    During migration, birds substantially increase their metabolic rate and burn fats as fuel and yet somehow avoid succumbing to overwhelming oxidative damage. The physiological means by which vertebrates such as migrating birds can counteract an increased production of reactive species (RS) are rather limited: they can upregulate their endogenous antioxidant system and/or consume dietary antioxidants (prophylactically or therapeutically). Thus, birds can alter different components of their antioxidant system to respond to the demands of long-duration flights, but much remains to be discovered about the complexities of RS production and antioxidant protection throughout migration. Here, we use bird migration as an example to discuss how RS are produced during endurance exercise and how the complex antioxidant system can protect against cellular damage caused by RS. Understanding how a bird's antioxidant system responds during migration can lend insights into how antioxidants protect birds during other life-history stages when metabolic rate may be high, and how antioxidants protect other vertebrates from oxidative damage during endurance exercise. © 2016. Published by The Company of Biologists Ltd.

  12. 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

  13. High migration rates shape the postglacial history of amphi-Atlantic bryophytes.

    Science.gov (United States)

    Désamoré, Aurélie; Patiño, Jairo; Mardulyn, Patrick; Mcdaniel, Stuart F; Zanatta, Florian; Laenen, Benjamin; Vanderpoorten, Alain

    2016-11-01

    Paleontological evidence and current patterns of angiosperm species richness suggest that European biota experienced more severe bottlenecks than North American ones during the last glacial maximum. How well this pattern fits other plant species is less clear. Bryophytes offer a unique opportunity to contrast the impact of the last glacial maximum in North America and Europe because about 60% of the European bryoflora is shared with North America. Here, we use population genetic analyses based on approximate Bayesian computation on eight amphi-Atlantic species to test the hypothesis that North American populations were less impacted by the last glacial maximum, exhibiting higher levels of genetic diversity than European ones and ultimately serving as a refugium for the postglacial recolonization of Europe. In contrast with this hypothesis, the best-fit demographic model involved similar patterns of population size contractions, comparable levels of genetic diversity and balanced migration rates between European and North American populations. Our results thus suggest that bryophytes have experienced comparable demographic glacial histories on both sides of the Atlantic. Although a weak, but significant genetic structure was systematically recovered between European and North American populations, evidence for migration from and towards both continents suggests that amphi-Atlantic bryophyte population may function as a metapopulation network. Reconstructing the biogeographic history of either North American or European bryophyte populations therefore requires a large, trans-Atlantic geographic framework. © 2016 John Wiley & Sons Ltd.

  14. [Migration and urbanization in the Sahel. Consequences of the Sahelian migrations].

    Science.gov (United States)

    Traore, S

    1997-10-01

    The consequences of Sahelian migration are multiple and diverse. In rural areas there may be a loss of income in the short run and a reduced possibility of development in the long run. Apart from its implications for urban growth, Sahelian migration may have four series of consequences in the places of origin. In detaching peasants from their lands, migration may contribute to loss of appreciation and reverence for the lands. Attachment to the lands of the ancestors loses its meaning as soon as questions of survival or economic rationality are raised. Migration contributes to the restructuring of the societies of origin. Increasing monetarization of market relations and introduction of new needs create new norms that favor stronger integration into the world economy. Migration may cause a decline in production because of the loss of the most active population, and it changes the age and sex distribution of households and usually increases their dependency burden. The effects on fertility and mortality are less clear. The effects of migration on the zones of arrival in the Sahel depend on the type of area. Conflicts between natives and in-migrants are common in rural-rural migration. Degradation of land may result from the increased demands placed upon it. Migrants to cities in Africa, and especially in the Sahel, appear to conserve their cultural values and to transplant and reinterpret their village rules of solidarity.

  15. Gas migration characteristics of highly compacted bentonite ore

    International Nuclear Information System (INIS)

    Tanaka, Yukihisa; Hironaga, Michihiko

    2010-01-01

    In the current concept of repository for radioactive waste disposal, compacted bentonite will be used as an engineered barrier mainly for inhibiting migration of radioactive nuclides. Hydrogen gas can be generated inside the engineered barrier by anaerobic corrosion of metals used for containers, etc. If the gas generation rate exceeds the diffusion rate of dissolved gas inside of the engineered barrier, gas will accumulate in the void space inside of the engineered barrier until its pressure becomes large enough for it to enter the bentonite as a discrete gaseous phase. It is expected to be not easy for gas to entering into the bentonite as a discrete gaseous phase because the pore of compacted bentonite is so minute. Gas migration characteristics of highly compacted powdered bentonite are already reported by CRIEPI. In this report, gas migration characteristics of bentonite ore, which is a candidate for construction material of repository for radioactive waste, is investigated. The following conclusions are obtained through the results of the gas migration tests which are conducted in this study: 1) When the total gas pressure exceeds the initial total axial stress, the total axial stress is always equal to the total gas pressure because specimens shrink in the axial direction with causing the clearance between the end of the specimen and porous metal. By increasing the gas pressure more, gas breakthrough, which defined as a sudden and sharp increase in gas flow rate out of the specimen, occurs. Therefore gas migration mechanism of compacted bentonite ore is basically identical to that of compacted powdered bentonite. 2) Hydraulic conductivity measured after the gas breakthrough is somewhat smaller than that measured before the gas migration test. This fact means that it might be possible to neglect decline of the function of bentonite as engineered barrier caused by the gas breakthrough. These characteristics of compacted bentonite ore are identical to those of

  16. Effect of migration based on strategy and cost on the evolution of cooperation

    International Nuclear Information System (INIS)

    Li, Yan; Ye, Hang

    2015-01-01

    Highlights: •Propose a migration based on strategy and cost in the Prisoner’s Dilemma Game. •The level of cooperation without mutation is higher than that with mutation. •Increased costs have no effect on the level of cooperation without mutation. •The level of cooperation decreases with the increase in cost with mutation. •An optimal density value ρ resulting in the maximum level of cooperation exists. -- Abstract: Humans consider not only their own ability but also the environment around them during the process of migration. Based on this fact, we introduce migration based on strategy and cost into the Spatial Prisoner’s Dilemma Game on a two-dimensional grid. The migration means that agents cannot move when all of the neighbors are cooperators; otherwise, agents move with a probability related to payoff and cost. The result obtained by the computer simulation shows that the moving mechanism based on strategy and cost improves the level of cooperation in a wide parameter space. This occurs because movement based on strategy effectively keeps the cooperative clusters and because movement based on cost effectively regulates the rate of movement. Both types of movement provide a favorable guarantee for the evolution of stable cooperation under the mutation rate q = 0.0. In addition, we discuss the effectiveness of the migration mechanism in the evolution of cooperation under the mutation rate q = 0.001. The result indicates that a higher level of cooperation is obtained at a lower migration cost, whereas cooperation is suppressed at a higher migration cost. Our work may provide an effective method for understanding the emergence of cooperation in our society

  17. 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.

  18. Internal migration and unemployment in Germany: an Anglo-Irish perspective.

    Science.gov (United States)

    Keil, M; Newell, A

    1993-01-01

    "The paper analyzes the effect on the migration rate of a number of labour market variables; in particular, relative wage levels and growth rates, and the relative unemployment rates in the home and foreign country. We study the Ireland-U.K. migration rate and use the estimates to predict migration between the two parts of unified Germany. We conclude that magnitudes of unemployment differences and wage differentials are such that currently observed substantial migration flows will not slow down for the forseeable future." (SUMMARY IN GER) excerpt

  19. 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

  20. Evaluating the rate of migration of an uranium deposition front within the Uitenhage Aquifer

    CSIR Research Space (South Africa)

    Vogel

    1999-07-01

    Full Text Available of Geochemical Exploration 66 (1999) 269?276 www.elsevier.com/locate/jgeoexp Evaluating the rate of migration of an uranium deposition front within the Uitenhage Aquifer J.C. Vogel a,A.S.Talmaa, T.H.E. Heaton b, J. Kronfeld c,* a Quaternary Dating Research Unit... stream_source_info vogel_1999.pdf.txt stream_content_type text/plain stream_size 18078 Content-Encoding ISO-8859-1 stream_name vogel_1999.pdf.txt Content-Type text/plain; charset=ISO-8859-1 ELSEVIER Journal...

  1. Moving Across Boundaries: Migration in South Africa, 1950–2000

    Science.gov (United States)

    2013-01-01

    Existing knowledge about historical patterns of black internal migration in South Africa is incomplete, primarily because of the lack of good life course studies as well as the apartheid government’s suppression and censoring of data. This article provides a comprehensive picture of historical internal migration patterns with an analysis of a unique individual retrospective life history data set. This sample of the black population, collected in 2000, is the only known nationally representative life history data for South Africa; it includes all residential moves for each individual during his/her lifetime. Various mobility outcomes are analyzed: moves within/across provinces, moves within/across rural and urban areas, forced moves, moves with a nuclear family, and individual moves. The results indicate that migration significantly increased among black South Africans during the last half of the twentieth century, and that this increase began before the Pass Laws were repealed in 1986 and well before the official end of apartheid in 1991 or the first free election in 1994. The timing of this increase in migration rates suggests that migration in defiance of the Pass Laws (albeit a dangerous and desperate proposition) was a way of life for many black South Africans. PMID:22956415

  2. Tritium migration studies at the Nevada Test Site

    International Nuclear Information System (INIS)

    Schulz, R.K.; Weaver, M.O.

    1993-05-01

    Emanation of tritium from waste containers is a commonly known phenomenon. Release of tritium from buried waste packages was anticipated; therefore, a research program was developed to study both the rate of tritium release from buried containers and subsequent migration of tritium through soil. Migration of tritium away from low-level radioactive wastes buried in Area 5 of the Nevada Test Site was studied. Four distinct disposal events were investigated. The oldest burial event studied was a 1976 emplacement of 3.5 million curies of tritium in a shallow land burial trench. In another event, 248 thousand curies of tritium was disposed of in an overpack emplaced 6 m below the floor of a low-level waste disposal pit. Measurement of the emanation rate of tritium out of 55 gallon drums to the overpack was studied, and an annual doubling of the emanation rate over a seven year period, ending in 1990, was found. In a third study, upward tritium migration in the soil, resulting in releases in the atmosphere were observed in a greater confinement disposal test. Releases of tritium to the atmosphere were found to be insignificant. The fourth event consisted of burial of 2.2 million curies of tritium in a greater confinement disposal operation. Emanation of tritium from the buried containers has been increasing since disposal, but no significant migration was found four years following backfilling of the disposal hole

  3. Hydrogen migration in Lu at low temperatures

    International Nuclear Information System (INIS)

    Yamakawa, K.

    1997-01-01

    The migration of hydrogen in Lu is determined by electrical resistance measurements in temperature range of 140-170 K. Disordered hydrogen atoms, which are formed by quenching, migrate to order during annealing in the above temperature range. The rate of the resistance decrease depends on the ordering rate of hydrogen. From the resistance decrease during isothermal annealings, the activation energy of hydrogen migration is determined as 0.43 eV (41.5 kJ mol -1 ). (orig.)

  4. Macro patterns of internal migration in Indonesia, 1971-1990.

    Science.gov (United States)

    Alatas, S

    1993-12-01

    Indonesia's population mobility rate is still relatively low. In 1990 only 8.25% of Indonesians lived outside the provinces where they were born. In contrast, according to the US censuses, since the 1870s no fewer than 20% of Americans did. The level of population mobility is even lower for inter-island and interregional migration. In 1990 only 4.29% of Indonesians lived outside their home islands or regions. The level of urbanization has also had an impact, with rural-urban migration increasing from 17.18% in 1971 to 22.38% in 1980, and to 30.93% in 1990. Between 1971 and 1990 the increase amounted to 20.34% in Jakarta, Surbaya, Bandung, Medan, and Semarang. Migration occurs because people want to improve their lives. The reasons for migration include: 1) to continue education, 2) to search for a better job, 3) to obtain better wages or income, 4) to accompany parents or spouse, 5) to secure political support, and 6) to escape from unpleasant conditions. The 1990 census data on migration were derived from 1) province of birth, 2) province of previous residence, 3) duration of residence at the current province, and 4) province of residence 5 years prior to the census. Interprovincial life time migration increased in Indonesia from 5.8 million in 1971 to 10.2 million in 1980 and to 14.8 million in 1990. Most of the provinces of Sumatra and Kalimantan experienced net positive migration in which in-migration exceeded out-migration. On the other hand, migrants from Jakarta to West Java accounted for 75.6% or 794,987 out of the 1,052,234 people who moved out of the capital city. In 1971 as much as 31.18% of migration across provincial borders headed for DKI Jakarta. In 1990 DKI Jakarta and West Java accommodated 37.75% of the interprovincial migrants. Recent in, out, and net migration declined 2.8 million between 1980 and 1985, but it went up to 5.3 million between 1985 and 1990. Between 1985 and 1990 interprovincial migration towards urban areas amounted to 3.2 million

  5. 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...

  6. Gas migration mechanism of saturated dense bentonite and its modeling

    International Nuclear Information System (INIS)

    Tanaka, Yukihisa; Hironaga, Michihiko; Kudo, Koji

    2007-01-01

    In the current concept of repository for nuclear waste disposal, compacted bentonite will be used as an engineered barrier mainly for inhibiting migration of radioactive nuclides. Hydrogen gas can be generated inside the engineered barrier by anaerobic corrosion of metals used for containers, etc. If the gas generation rate exceeds the diffusion rate of gas molecules inside of the engineered barrier, gas will accumulate in the void space inside of the engineered barrier until its pressure becomes large enough for it to enter the bentonite as a discrete gaseous phase. It is expected to be not easy for gas to entering into the bentonite as a discrete gaseous phase because the pore of compacted bentonite is so minute. Therefore it is necessary to investigate the following subjects: a) Effect of the accumulated gas pressure on surrounding objects such as concrete lining, rock mass. b) Effect of gas breakthrough on the barrier function of bentonite. c) Revealing and modeling gas migration mechanism for overcoming the scale effects in laboratory specimen test. Therefore in this study, gas migration tests for compacted and saturated bentonite to investigate and to model the mechanism of gas migration phenomenon. Firstly, the following conclusions were obtained through by the results of the gas migration tests which are conducted in this study: 1) Bubbles appear in the semitransparent drainage tube at first when the total gas is equal to the initial total axial stress or somewhat smaller. By increasing the gas pressure more, breakthrough of gas migration, which is defined as a sudden increase of amount of emission gas, occurred. When the total gas pressure exceeds the initial total axial stress, the total axial stress is always equal to the total gas pressure because specimens shrink in the axial direction with causing the clearance between the end of the specimen and porous metal. 2) Effective gas conductivity after breakthrough of gas migration is times larger than that

  7. Extremely low frequency electromagnetic fields promote mesenchymal stem cell migration by increasing intracellular Ca2+ and activating the FAK/Rho GTPases signaling pathways in vitro.

    Science.gov (United States)

    Zhang, Yingchi; Yan, Jiyuan; Xu, Haoran; Yang, Yong; Li, Wenkai; Wu, Hua; Liu, Chaoxu

    2018-05-21

    The ability of mesenchymal stem cells (MSCs) to migrate to the desired tissues or lesions is crucial for stem cell-based regenerative medicine and tissue engineering. Optimal therapeutics for promoting MSC migration are expected to become an effective means for tissue regeneration. Electromagnetic fields (EMF), as a noninvasive therapy, can cause a lot of biological changes in MSCs. However, whether EMF can promote MSC migration has not yet been reported. We evaluated the effects of EMF on cell migration in human bone marrow-derived MSCs. With the use of Helmholtz coils and an EMF stimulator, 7.5, 15, 30, 50, and 70 Hz/1 mT EMF was generated. Additionally, we employed the L-type calcium channel blocker verapamil and the focal adhesion kinase (FAK) inhibitor PF-573228 to investigate the role of intracellular calcium content, cell adhesion proteins, and the Rho GTPase protein family (RhoA, Rac1, and Cdc42) in EMF-mediated MSC migration. Cell adhesion proteins (FAK, talin, and vinculin) were detected by Western blot analysis. The Rho GTPase protein family activities were assessed by G-LISA, and F-actin levels, which reflect actin cytoskeletal organization, were detected using immunofluorescence. All the 7.5, 15, 30, 50, and 70 Hz/1 mT EMF promoted MSC migration. EMF increased MSC migration in an intracellular calcium-dependent manner. Notably, EMF-enhanced migration was mediated by FAK activation, which was critical for the formation of focal contacts, as evidenced by increased talin and vinculin expression. Moreover, RhoA, Rac1, and Cdc42 were activated by FAK to increase cytoskeletal organization, thus promoting cell contraction. EMF promoted MSC migration by increasing intracellular calcium and activating the FAK/Rho GTPase signaling pathways. This study provides insights into the mechanisms of MSC migration and will enable the rational design of targeted therapies to improve MSC engraftment.

  8. Reduced Dietary Sodium Intake Increases Heart Rate

    DEFF Research Database (Denmark)

    Graudal, Niels A; Hubeck-Graudal, Thorbjørn; Jürgens, Gesche

    2016-01-01

    Reduced dietary sodium intake (sodium reduction) increases heart rate in some studies of animals and humans. As heart rate is independently associated with the development of heart failure and increased risk of premature death a potential increase in heart rate could be a harmful side......-effect of sodium reduction. The purpose of the present meta-analysis was to investigate the effect of sodium reduction on heart rate. Relevant studies were retrieved from an updated pool of 176 randomized controlled trials (RCTs) published in the period 1973-2014. Sixty-three of the RCTs including 72 study...... populations reported data on heart rate. In a meta-analysis of these data sodium reduction increased heart rate with 1.65 beats per minute [95% CI: 1.19, 2.11], p heart rate. This effect was independent of baseline blood pressure. In conclusion sodium reduction...

  9. The Demographic Crisis and Global Migration - Selected Issues

    Science.gov (United States)

    Frątczak, Ewa Zofia

    2016-01-01

    Currently the world is undergoing a serious demographic shift, characterised by slowing population growth in developed countries. However, the population in certain less-developed regions of the world is still increasing. According to UN data, as of 2015, (World...2015), 244 million people (or 3.3% of the global population) lived outside their country of birth. While most of these migrants travel abroad looking for better economic and social conditions, there are also those forced to move by political crises, revolutions and war. Such migration is being experienced currently in Europe, a continent which is thus going through both a demographic crisis related to the low fertility rate and population ageing, and a migration crisis. Global migrations link up inseparably with demographic transformation processes taking place globally and resulting in the changing tempo of population growth. Attracting and discouraging migration factors are changing at the same time, as is the scale and range of global migration, and with these also the global consequences. The focus of work addressed in this paper is on global population, the demographic transformation and the role of global migrations, as well as the range and scale of international migration, and selected aspects of global migrations including participation in the global labour market, the scale of monetary transfers (remittances) and the place of global migration in the UN 2030 Agenda for Sustainable Development (Transforming...2015) and the Europe of two crises (Domeny 2016).

  10. Predicting Agency Rating Migrations with Spread Implied Ratings

    OpenAIRE

    Jianming Kou; Dr Simone Varotto

    2005-01-01

    Investors traditionally rely on credit ratings to price debt instruments. However, rating agencies are known to be prudent in their approach to rating revisions, which results in delayed ratings adjustments to mutating credit conditions. For a large set of eurobonds we derive credit spread implied ratings and compare them with the ratings issued by rating agencies. Our results indicate that spread implied ratings often anticipate future movement of agency ratings and hence could help track cr...

  11. Gas generation and migration analysis for TRU waste disposal system

    International Nuclear Information System (INIS)

    Ando, Kenichi; Noda, Masaru; Yamamoto, Mikihiko; Mihara, Morihiro

    2005-09-01

    In TRU waste disposal system, significant quantities of gases may be generated due to metal corrosion, radiolysis effect and microorganism activities. It is therefore recommended that the potential impact of gas generation and migration on TRU waste repository should be evaluated. In this study, gas generation rates were calculated in the repository and gas migration analysis in the disposal system were carried out using two phase flow model with results of gas generation rates. First, the time dependencies of gas generation rate in each TRU waste repositories were evaluated based on amounts of metal, organic matter and radioactivity. Next, the accumulation pressure of gases and expelled pore water volume nuclides in the repository were calculated by TOUGH2 code. After that, the results showed that the increase of gas pressure was the range of 1.3 to 1.4 MPa. In the repository with and without buffer, the rate of expelled pore water was 0.006 - 0.009 m 3 /y and 0.018 - 0.24m 3 /y, respectively. In addition, the radioactive gas migration through the repository and geosphere are evaluated. And re-saturation analysis is also performed to evaluate the initial condition of the system. (author)

  12. Recovery Migration to the City of New Orleans after Hurricane Katrina: A Migration Systems Approach.

    Science.gov (United States)

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

    2014-03-01

    Hurricane Katrina's effect on the population of the City of New Orleans provides a model of how severe weather events, which are likely to increase in frequency and strength as the climate warms, might affect other large coastal cities. Our research focuses on changes in the migration system - defined as the system of ties between Orleans Parish and all other U.S. counties - between the pre-disaster (1999-2004) and recovery (2007-2009) periods. Using Internal Revenue Service county-to-county migration flow data, we find that in the recovery period Orleans Parish increased the number of migration ties with and received larger migration flows from nearby counties in the Gulf of Mexico coastal region, thereby spatially concentrating and intensifying the in-migration dimension of this predominantly urban system, while the out-migration dimension contracted and had smaller flows. We interpret these changes as the migration system relying on its strongest ties to nearby and less damaged counties to generate recovery in-migration.

  13. Population growth and rural-urban migration, with special reference to Ghana.

    Science.gov (United States)

    De Graft-johnson, K T

    1974-01-01

    While the population of Ghana is expected to double in 25 years at the current rate of increase (approximately 2.5% per annum), the population of urban centers is increasing even faster. The 1970 census shows the urban population growing by 4.8% per annum. This is mainly the result of rural to urban migration and, to a smaller extent, the increase in the number of urban centers from 39 in 1948 to 98 in 1960 to 135 in 1970. In the 1970 census only 57.1% of the population were enumerated in their locality of birth and only 20.9% in a locality other than their place of birth but in the same region. 4.1% were born outside Ghana, mostly in another West African country. 1 striking difference between urban and rural areas is the differing sex ratio of the working population. In rural areas there are 91.0 males aged 15-64 years for every 100 females while in urban areas there are 107.1. Most migration in Africa is for employment and those most likely to migrate are working-age males. Because secondary schools are scarce in rural areas, urban dwellers generally have a higher education level. There are no significant differences between overall labor force participation rates for females. The nationwide participation rate was 38.9% for both males and females (males 43.8%, females 34.1%); in urban areas the total was 40.0% (males 46.3%, females 33.7%) and in rural areas 38.5% (males 42.7%, females 34.3%). Ghanaian women have traditionally occupied a prominent place in the labor force. The theory that urban migration is due to urban-rural income disparities is not confirmed by figures. Considering the high amount of unemployment in urban areas, a rural dweller can average as much as a city dweller. In fact, poorly educated migrants are the ones most affected by urban unemployment. A recent study by Kodwo Ewusi considered the impact of many variables on migration; he found depressed social conditions at the place of origin are more compelling motivations than economic factors

  14. [Contribution of migrations to the process of urbanization].

    Science.gov (United States)

    Bocquier, P

    1997-10-01

    An average of 22% of the populations of the Sahel countries resided in urban areas in the mid-1970s, a lower level than in the rest of sub-Saharan Africa. The proportion urban has increased by about 5.5% annually over the past 2 decades. By 1993, four Sahel countries had over 30% of their populations in urban areas, and only Burkina Faso had less than 20% urban. The landlocked Sahel countries of Burkina Faso, Mali, Niger, and Chad have maintained rates of urbanization comparable to those of the coastal countries (Cape Verde, Gambia, Mauritania, and Senegal), which had more significant levels of urbanization in the past. The rate of growth of the urban population of all of sub-Saharan Africa was around 5.0% during the past 20 years. Only Dakar among the Sahel capitals has a population of over 1 million. Cities are small, and the urban environment is usually limited to the capital. In Guinea-Bissau, for example, the capital concentrates nearly 85% of the urban population. The increased rates of urbanization are due mainly to migration. In the landlocked countries covered by surveys of the Migration and Urbanization Networks in Western Africa (Burkina Faso, Mali, and Niger), the rural exodus was directed primarily to other countries. In Senegal and Mauritania, on the other hand, around two-thirds of migrations were internal. Women contribute more than men to urban growth in the Sahel. Returning migrants also show a strong preference for capital cities. Labor markets are international for men but national for women. Urban unemployment rates in the Sahel countries studied were lower for migrants than nonmigrants.

  15. The influence of weather on Golden Eagle migration in northwestern Montana

    Science.gov (United States)

    Yates, R.E.; McClelland, B.R.; Mcclelland, P.T.; Key, C.H.; Bennetts, R.E.

    2001-01-01

    We analyzed the influence of 17 weather factors on migrating Golden Eagles (Aquila chrysaetos) near the Continental Divide in Glacier National Park, Montana, U.S.A. Local weather measurements were recorded at automated stations on the flanks of two peaks within the migration path. During a total of 506 hr of observation, the yearly number of Golden Eagles in autumn counts (1994-96) averaged 1973; spring counts (1995 and 1996) averaged 605 eagles. Mean passage rates (eagles/hr) were 16.5 in autumn and 8.2 in spring. Maximum rates were 137 in autumn and 67 in spring. Using generalized linear modeling, we tested for the effects of weather factors on the number of eagles counted. In the autumn model, the number of eagles increased with increasing air temperature, rising barometric pressure, decreasing relative humidity, and interactions among those factors. In the spring model, the number of eagles increased with increasing wind speed, barometric pressure, and the interaction between these factors. Our data suggest that a complex interaction among weather factors influenced the number of eagles passing on a given day. We hypothesize that in complex landscapes with high topographic relief, such as Glacier National Park, numerous weather factors produce different daily combinations to which migrating eagles respond opportunistically. ?? 2001 The Raptor Research Foundation, Inc.

  16. Migration and common mental disorder: an improvement in mental health over time?

    Science.gov (United States)

    Butler, Margaret; Warfa, Nasir; Khatib, Yasmin; Bhui, Kamaldeep

    2015-02-01

    Global migration is reaching record high levels and UK migrant groups comprise an increasing proportion of the total population. The migratory process causes stress that can affect mental health. There is limited consistent empirical evidence of a longitudinal nature to explain the association between migration and mental health. This review aims to examine the evidence of a relationship between migration and common mental disorder (CMD) amongst migrants over time. A comprehensive search of medical and psychiatric databases for global quantitative empirical studies investigating incidence of CMD amongst adult migrants from 1975 to July 2012 was conducted. Declines in rates of CMD amongst migrants over time were reported by two thirds of the 18 studies reviewed, less than one third of which were statistically significant. On the contrary, three studies showed an increased rate of CMD, one statistically significant. Individual psychological resources, social support, the acculturation process, cultural variations and time since relocation are identified as statistically significant protective factors against the development of CMD amongst migrants. New enlightening points include the significant impact of varying patterns of psychological distress, of which negative is the most adverse for CMD. Migration is an extremely complex process. Further clarification is needed to gain deeper understanding of the relationship between migration and CMD to address contradictions in the literature and health inequalities amongst migrants.

  17. MIGRATION AND REGIONAL DEVELOPMENT IN ROMANIA

    Directory of Open Access Journals (Sweden)

    CAMELIA ANGHEL

    2017-12-01

    Full Text Available Economic implications of demographic decline and the changing age structure will be more visible in Romania after 2020, when the working population will decrease gradually and "mature" groups will come in the elderly population. Diminishing populations will cause a change in the economic dependency ratio and total economic burden of the working population will increase. The changes known in activity rates in the future are hard to predict, especially in the current context of labor migration in Europe. In this context, a realistic vision of economic and social development in the coming decades is a necessity for Romania. Where the countries of origin of migrants fail to implement clear and efficient social and economic general reforms, migration and remittances get involved whose fundamental purpose is although they do not contribute to the sustainable development at the national level. Population migration has now become a global issue important to the development and welfare societies. Remittances are the main concern in studies of migration and development, migration transnational model several years as part of concerns about the economic future of many countries. Focus as well can be seen throughout this paper falls on cash remittances and consumer goods, on issues related to sustainable development, social development, human development. Many experts consider impossible the debate on economic development without taking into account human and social development, even sustainable development.

  18. North-South Migration and Remittances in Ghana

    African Journals Online (AJOL)

    mobility and high rates of rural-urban migration and in recent times child migration .... after the migrant settles at the place of destination and his income profile starts rising .... the rural areas of Northern Ghana had little or no education. ... The poor educational infrastructure, lack of schools and teachers, high dropout rates.

  19. Pre-migration persecution, post-migration stressors and resources, and post-migration mental health: A study of severely traumatized U.S. Arab immigrant women

    Science.gov (United States)

    Norris, Anne E.; Aroian, Karen J.; Nickerson, David

    2015-01-01

    Background Competing theories exist regarding the importance of pre-migration trauma as compared to post-migration stressors and resources with respect to the risk to immigrant mental health. Objective To examine how type of pre-migration trauma, post-migration stressors, and post-migration resources differentially predict PTSD and MDD symptomatology in Arab immigrant women who have been exposed to pre-migration trauma. Design Descriptive; using multinomial logistic regression to explain membership in one of four groups: (a) PTSD only (n = 14); (b) major depressive disorder (MDD) (n = 162), (c) Co-Morbid PTSD-MDD (n = 148), (d) Subclinical Symptoms (n = 209). Results Post-immigration related stressors (as measured by the Demands of Immigration (DI)) had the strongest effect: Parameter estimates indicated that a unit increase in DI scores was associated with a nearly 17 fold increase in the likelihood of being in the Co-morbid relative to the Subclinical group, and a nearly 2.5 increase in the likelihood of being in the Co-Morbid relative to the MDD only group (p Arab immigrant women for depression and PTSD is important given high levels observed in this community based sample. PMID:21835819

  20. Kinetic evolutionary behavior of catalysis-select migration

    International Nuclear Information System (INIS)

    Wu Yuan-Gang; Lin Zhen-Quan; Ke Jian-Hong

    2012-01-01

    We propose a catalysis-select migration driven evolution model of two-species (A- and B-species) aggregates, where one unit of species A migrates to species B under the catalysts of species C, while under the catalysts of species D the reaction will become one unit of species B migrating to species A. Meanwhile the catalyst aggregates of species C perform self-coagulation, as do the species D aggregates. We study this catalysis-select migration driven kinetic aggregation phenomena using the generalized Smoluchowski rate equation approach with C species catalysis-select migration rate kernel K(k;i,j) = Kkij and D species catalysis-select migration rate kernel J(k;i,j)= Jkij. The kinetic evolution behaviour is found to be dominated by the competition between the catalysis-select immigration and emigration, in which the competition is between JD 0 and KC 0 (D 0 and C 0 are the initial numbers of the monomers of species D and C, respectively). When JD 0 −KC 0 > 0, the aggregate size distribution of species A satisfies the conventional scaling form and that of species B satisfies a modified scaling form. And in the case of JD 0 −KC 0 0 −KC 0 > 0 case. (interdisciplinary physics and related areas of science and technology)

  1. 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.

  2. International migration and educational assortative mating in Mexico and the United States.

    Science.gov (United States)

    Choi, Kate H; Mare, Robert D

    2012-05-01

    This paper examines the relationship between migration and marriage by describing how the distributions of marital statuses and assortative mating patterns vary by individual and community experiences of migration. In Mexico, migrants and those living in areas with high levels of out-migration are more likely to be in heterogamous unions. This is because migration increases the relative attractiveness of single return migrants while disproportionately reducing the number of marriageable men in local marriage markets. In the United States, the odds of homogamy are lower for migrants compared with nonmigrants; however, they do not vary depending on the volume of migration in communities. Migrants are more likely than nonmigrants to "marry up" educationally because the relatively small size of this group compels them to expand their pool of potential spouses to include nonmigrants, who tend to be better educated than they are. Among migrants, the odds of marrying outside of one's education group increase the most among the least educated. In Mexican communities with high rates of out-migration, the odds of marrying outside of one's education group are highest among those with the highest level of education. These findings suggest that migration disrupts preferences and opportunities for homogamy by changing social arrangements and normative climates.

  3. α and β deuterium isotope effects in the hydrolysis of naphthalene tetrahydro epoxides: rate-limiting hydrogen migration in the spontaneous hydrolysis of 6-methoxy-1,2,3,4-tetrahydronaphthalene oxide

    International Nuclear Information System (INIS)

    Gillilan, R.E.; Pohl, T.M.; Whalen, D.L.

    1982-01-01

    Data are reported that indicate that 6-methoxy-1,2,3-tetrahydronaphthalene oxide undergoes a spontaneous reaction to yield mostly 6-methyoxy-2-tetralone. Hydrogen-migration is reported to be the rate determining step in the reaction. Reaction mechanisms involving a one-step reaction with a concurrent C-O bond cleavage and hydrogen migration or reversible C-O bond cleavage followed by the rate-limiting hydrogen migration are proposed, but no clear distinction between the schemes is made

  4. Migration of accreting giant planets

    Science.gov (United States)

    Crida, A.; Bitsch, B.; Raibaldi, A.

    2016-12-01

    We present the results of 2D hydro simulations of giant planets in proto-planetary discs, which accrete gas at a more or less high rate. First, starting from a solid core of 20 Earth masses, we show that as soon as the runaway accretion of gas turns on, the planet is saved from type I migration : the gap opening mass is reached before the planet is lost into its host star. Furthermore, gas accretion helps opening the gap in low mass discs. Consequently, if the accretion rate is limited to the disc supply, then the planet is already inside a gap and in type II migration. We further show that the type II migration of a Jupiter mass planet actually depends on its accretion rate. Only when the accretion is high do we retrieve the classical picture where no gas crosses the gap and the planet follows the disc spreading. These results impact our understanding of planet migration and planet population synthesis models. The e-poster presenting these results in French can be found here: L'e-poster présentant ces résultats en français est disponible à cette adresse: http://sf2a.eu/semaine-sf2a/2016/posterpdfs/156_179_49.pdf.

  5. Can migration mitigate the effects of ecosystem change? Patterns of dispersal, energy acquisition and allocation in Great Lakes lake whitefish (Coregonus clupeaformis)

    Science.gov (United States)

    Rennie, Michael D.; Ebener, Mark P.; Wagner, Tyler

    2012-01-01

    Migration can be a behavioural response to poor or declining home range habitat quality and can occur when the costs of migration are overcome by the benefi ts of encountering higher-quality resources elsewhere. Despite dramatic ecosystem-level changes in the benthic food web of the Laurentian Great Lakes since the colonization of dreissenid mussels, coincident changes in condition and growth rates among benthivorous lake whitefi sh populations have been variable. We hypothesized that this variation could be in part mitigated by differences in migratory habits among populations, where increased migration distance can result in an increased probability of encountering high-quality habitat (relative to the home range). Results from four Great Lakes populations support this hypothesis; relative growth rates increased regularly with migration distance. The population with the largest average migration distance also had the least reduction in size-at-age during a period of signifi cant ecosystem change and among the highest estimated consumption and activity rates. In comparison, the population with the greatest declines in size-at-age was among the least mobile, demonstrating only moderate rates of consumption and activity. The least mobile population of lake whitefi sh was supported by a remnant Diporeia population and has experienced only moderate temporal growth declines. Our study provides evidence for the potential role of migration in mitigating the effects of ecosystem change on lake whitefi sh populations.

  6. 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...

  7. Ang II-AT2R increases mesenchymal stem cell migration by signaling through the FAK and RhoA/Cdc42 pathways in vitro.

    Science.gov (United States)

    Xu, Xiu-Ping; He, Hong-Li; Hu, Shu-Ling; Han, Ji-Bin; Huang, Li-Li; Xu, Jing-Yuan; Xie, Jian-Feng; Liu, Ai-Ran; Yang, Yi; Qiu, Hai-Bo

    2017-07-12

    Mesenchymal stem cells (MSCs) migrate via the bloodstream to sites of injury and are possibly attracted by inflammatory factors. As a proinflammatory mediator, angiotensin II (Ang II) reportedly enhances the migration of various cell types by signaling via the Ang II receptor in vitro. However, few studies have focused on the effects of Ang II on MSC migration and the underlying mechanisms. Human bone marrow MSCs migration was measured using wound healing and Boyden chamber migration assays after treatments with different concentrations of Ang II, an AT1R antagonist (Losartan), and/or an AT2R antagonist (PD-123319). To exclude the effect of proliferation on MSC migration, we measured MSC proliferation after stimulation with the same concentration of Ang II. Additionally, we employed the focal adhesion kinase (FAK) inhibitor PF-573228, RhoA inhibitor C3 transferase, Rac1 inhibitor NSC23766, or Cdc42 inhibitor ML141 to investigate the role of cell adhesion proteins and the Rho-GTPase protein family (RhoA, Rac1, and Cdc42) in Ang II-mediated MSC migration. Cell adhesion proteins (FAK, Talin, and Vinculin) were detected by western blot analysis. The Rho-GTPase family protein activities were assessed by G-LISA and F-actin levels, which reflect actin cytoskeletal organization, were detected by using immunofluorescence. Human bone marrow MSCs constitutively expressed AT1R and AT2R. Additionally, Ang II increased MSC migration in an AT2R-dependent manner. Notably, Ang II-enhanced migration was not mediated by Ang II-mediated cell proliferation. Interestingly, Ang II-enhanced migration was mediated by FAK activation, which was critical for the formation of focal contacts, as evidenced by increased Talin and Vinculin expression. Moreover, RhoA and Cdc42 were activated by FAK to increase cytoskeletal organization, thus promoting cell contraction. Furthermore, FAK, Talin, and Vinculin activation and F-actin reorganization in response to Ang II were prevented by PD-123319 but

  8. Migration, Multiple Sexual Partnerships, and Sexual Concurrency in the Garífuna Population of Honduras.

    Science.gov (United States)

    Gandhi, Anisha D; Pettifor, Audrey; Barrington, Clare; Marshall, Stephen W; Behets, Frieda; Guardado, Maria Elena; Farach, Nasim; Ardón, Elvia; Paz-Bailey, Gabriela

    2015-09-01

    The Garífuna, an ethnic minority group in Honduras, have been disproportionately affected by HIV. Previous research suggests that migration and high rates of multiple sexual partnerships are major drivers of the epidemic. Using data from a 2012 population-based survey, we assessed whether temporary migration was associated with (1) multiple sexual partnerships and (2) sexual concurrency among Garífuna men and women in Honduras. Among both men and women, temporary migration in the last year was associated with an increased likelihood of multiple sexual partnerships and with concurrency, though only the association between migration and multiple sexual partnerships among men was statistically significant (Adjusted Prevalence Ratio 1.7, 95 % CI 1.2-2.4). Migration may contribute to HIV/STI vulnerability among Garífuna men and women via increases in these sexual risk behaviors. Research conducted among men and women at elevated risk of HIV should continue to incorporate measures of mobility, including history of internal migration.

  9. Increased gastrointestinal blood flow: An essential circulatory modification for euryhaline rainbow trout (Oncorhynchus mykiss) migrating to sea

    Science.gov (United States)

    Brijs, Jeroen; Axelsson, Michael; Gräns, Albin; Pichaud, Nicolas; Olsson, Catharina; Sandblom, Erik

    2015-01-01

    The large-scale migrations of anadromous fish species from freshwater to seawater have long been considered particularly enigmatic, as this life history necessitates potentially energetically costly changes in behaviour and physiology. A significant knowledge gap concerns the integral role of cardiovascular responses, which directly link many of the well-documented adaptations (i.e. through oxygen delivery, water and ion transport) allowing fish to maintain osmotic homeostasis in the sea. Using long-term recordings of cardiorespiratory variables and a novel method for examining drinking dynamics, we show that euryhaline rainbow trout (Oncorhynchus mykiss) initiate drinking long before the surrounding environment reaches full seawater salinity (30–33 ppt), suggesting the presence of an external osmo-sensing mechanism. Onset of drinking was followed by a delayed, yet substantial increase in gastrointestinal blood flow through increased pulse volume exclusively, as heart rate remained unchanged. While seawater entry did not affect whole animal energy expenditure, enhanced gastrointestinal perfusion represents a mechanism crucial for ion and water absorption, as well as possibly increasing local gastrointestinal oxygen supply. Collectively, these modifications are essential for anadromous fish to maintain homeostasis at sea, whilst conserving cardiac and metabolic scope for activities directly contributing to fitness and reproductive success. PMID:26000616

  10. Lesion-induced increase in survival and migration of human neural progenitor cells releasing GDNF

    Science.gov (United States)

    Behrstock, Soshana; Ebert, Allison D.; Klein, Sandra; Schmitt, Melanie; Moore, Jeannette M.; Svendsen, Clive N.

    2009-01-01

    The use of human neural progenitor cells (hNPC) has been proposed to provide neuronal replacement or astrocytes delivering growth factors for brain disorders such as Parkinson’s and Huntington’s disease. Success in such studies likely requires migration from the site of transplantation and integration into host tissue in the face of ongoing damage. In the current study, hNPC modified to release glial cell line derived neurotrophic factor (hNPCGDNF) were transplanted into either intact or lesioned animals. GDNF release itself had no effect on the survival, migration or differentiation of the cells. The most robust migration and survival was found using a direct lesion of striatum (Huntington’s model) with indirect lesions of the dopamine system (Parkinson’s model) or intact animals showing successively less migration and survival. No lesion affected differentiation patterns. We conclude that the type of brain injury dictates migration and integration of hNPC which has important consequences when considering transplantation of these cells as a therapy for neurodegenerative diseases. PMID:19044202

  11. Individual Decisions to Migrate During Civil Conflict

    Science.gov (United States)

    Bohra-Mishra, Pratikshya; Massey, Douglas S.

    2012-01-01

    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. PMID:21541805

  12. Potential directions of the 'town-to-town' migration in Vojvodina

    Directory of Open Access Journals (Sweden)

    Savić Mirko

    2008-01-01

    Full Text Available Population of Vojvodina is showing the characteristics of late demographic transition. The main characteristics of that phase are low mortality rate, slow decrease of fertility rate, increased number of older people etc. This phase is connected to fourth development phase of migrations with significant migrations from one city to another and inside the city area. The purpose of this paper is to define the basic characteristics of potential internal migrations in the region of Vojvodina between cities, most of all towards Novi Sad as economic, political and cultural center. The sample of 2.000 respondents was formed and survey was conducted in the 15 largest cities in the region. The data were analyzed with methods of descriptive and multivariate statistical analysis (rank correlation and MDS analysis. Basic conclusions are that theory of transitional migration is confirmed in Vojvodina, the size of the city is not the only factor for potential migration movements and Novi Sad is by far the most desired destination for significant portion of population in the region, especially of population aged between 20 and 40 years because around 40% of that cohort wish to move to Novi Sad. That will cause significant urban, economic and social problems, not only in the city of Novi Sad but also in the cities where immigrants are coming from. .

  13. Plectin deficiency in liver cancer cells promotes cell migration and sensitivity to sorafenib treatment.

    Science.gov (United States)

    Cheng, Chiung-Chi; Chao, Wei-Ting; Liao, Chen-Chun; Tseng, Yu-Hui; Lai, Yen-Chang Clark; Lai, Yih-Shyong; Hsu, Yung-Hsiang; Liu, Yi-Hsiang

    2018-01-02

    Plectin involved in activation of kinases in cell signaling pathway and plays important role in cell morphology and migration. Plectin knockdown promotes cell migration by activating focal adhesion kinase and Rac1-GTPase activity in liver cells. Sorafenib is a multi-targeting tyrosine kinase inhibitor that improves patient survival on hepatocellular carcinoma. The aim of this study is to investigate the correlation between the expression of plectin and cell migration as well as the sensitivity of hepatoma cell lines exposing to sorafenib. Hepatoma cell lines PLC/PRF/5 and HepG2 were used to examine the level of plectin expression and cell migration in comparison with Chang liver cell line. In addition, sensitivity of the 3 cell lines to sorafenib treatment was also measured. Expression of plectin was lower in PLC/PRF/5 and HepG2 hepatoma cells than that of Chang liver cells whereas HepG2 and PLC/PRF/5 cells exhibit higher rate of cell migration in trans-well migration assay. Immunohistofluorecent staining on E-cadherin revealed the highest rate of collective cell migration in HepG2 cells and the lowest was found in Chang liver cells. Likewise, HepG2 cell line was most sensitive to sorafenib treatment and Chang liver cells exhibited the least sensitivity. The drug sensitivity to sorafenib treatment showed inverse correlation with the expression of plectin. We suggest that plectin deficiency and increased E-cadherin in hepatoma cells were associated with higher rates of cell motility, collective cell migration as well as higher drug sensitivity to sorafenib treatment.

  14. Effects of labour migration on economic development during economic downturn and recovery

    Directory of Open Access Journals (Sweden)

    Milan Palát

    2012-01-01

    Full Text Available International labour migration is mainly promoted by economic interests. This paper focuses on the period before and after the economic crisis and puts together important facts regarding motivation to labour migration and provides explanations of its causes and impacts on the macroeconomic level. The economic explanation why is migration so severely restricted is that migration policies are essentially distributive tools, aiming at reducing negative effects of migration on wages and unemployment among natives and moreover, we may stress out the gradualist tendencies of migration and such migration restrictions can mitigate supply-side shocks that may negatively affect incomes or jobs of some specific groups. A partial objective of the practical part of the paper is to evaluate relationships between the rate of migration and selected economic indicators using adequate quantitative methods. While the correlation between the crude rate of net migration and the GDP per capita is very low, the existence of correlation between the crude rate of net migration and the unemployment rate is evident in the most of analysed countries. Statistical insignificance of correlation indices in some countries can be then attributed to structural problems of those economies.

  15. Why Did People Move During the Great Recession? The Role of Economics in Migration Decisions

    Directory of Open Access Journals (Sweden)

    Brian L. Levy

    2017-04-01

    Full Text Available Labor migration offers an important mechanism to reallocate workers when there are regional differences in employment conditions. Whereas conventional wisdom suggests migration rates should increase during recessions as workers move out of areas that are hit hardest, initial evidence suggested that overall migration rates declined during the Great Recession, despite large regional differences in unemployment and growth rates. In this paper we use data from the American Community Survey to analyze internal migration trends before and during the economic downturn. First, we find only a modest decline in the odds of adults leaving distressed labor market areas during the Great Recession, which may result in part from challenges related to the housing price crash. Second, we estimate conditional logit models of destination choice for individuals who migrate across labor market areas; we find a substantial effect of economic factors such as labor demand, unemployment, and housing values. We also estimate latent class conditional logit models that test whether there is heterogeneity in preferences for destination characteristics among migrants. Over all, the latent class models suggest that roughly equal percentages of migrants were motivated by economic factors before and during the Great Recession. We conclude that fears of dramatic declines in labor migration seem to be unsubstantiated.

  16. Why Did People Move During the Great Recession?: The Role of Economics in Migration Decisions.

    Science.gov (United States)

    Levy, Brian L; Mouw, Ted; Daniel Perez, Anthony

    2017-04-01

    Labor migration offers an important mechanism to reallocate workers when there are regional differences in employment conditions. Whereas conventional wisdom suggests migration rates should increase during recessions as workers move out of areas that are hit hardest, initial evidence suggested that overall migration rates declined during the Great Recession, despite large regional differences in unemployment and growth rates. In this paper, we use data from the American Community Survey to analyze internal migration trends before and during the economic downturn. First, we find only a modest decline in the odds of adults leaving distressed labor market areas during the recession, which may result in part from challenges related to the housing price crash. Second, we estimate conditional logit models of destination choice for individuals who migrate across labor market areas and find a substantial effect of economic factors such as labor demand, unemployment, and housing values. We also estimate latent class conditional logit models that test whether there is heterogeneity in preferences for destination characteristics among migrants. Over all, the latent class models suggest that roughly equal percentages of migrants were motivated by economic factors before and during the recession. We conclude that fears of dramatic declines in labor migration seem to be unsubstantiated.

  17. Comparative studies on dyeing rate migration and wash fastness ...

    African Journals Online (AJOL)

    Migration and diffusion properties of synthesized azo dyes from 2-aminothiazole derivatives applied on commercial grade undyed cellulose acetate (CA) and cellulose triacetate (CTA) were investigated using dyeing conditions of 2% on weight of fabric (owf), 50:1 liquor ratio and subjected to ISO3 and ISO4 standard wash ...

  18. The health impacts of climate-related migration.

    Science.gov (United States)

    Schwerdtle, Patricia; Bowen, Kathryn; McMichael, Celia

    2017-12-11

    Changes in climate, in conjunction with other drivers of mobility, shape human migration. While there is an increasing focus on the adaptive potential of migration, the health impacts of climate-related migration, including planned relocation and forced displacement, have not been thoroughly examined. The Intergovernmental Panel on Climate Change stated that migration is currently, and will increasingly be, influenced by environmental degradation and climate change, and that it needs to be addressed in a focused and coordinated manner. This paper examines the links between climate change, migration, and health, considering diverse migration responses, including immobility, forced displacement and planned migration, as well as the associated health risks and opportunities in different contexts. Using case studies, the paper illustrates strategies to reduce the health risks associated with climate change-related migration. While there is an increasing body of research examining the climate change-migration nexus, a dual approach is now required. This approach must include debate and further research regarding the health consequences and responses associated with climate migration as well as immediate strengthening of health systems to make them both climate resilient and migrant inclusive.

  19. Income Inequality and Migration in Vietnam

    OpenAIRE

    NGUYEN, Tien Dung

    2012-01-01

    In this paper, we have analyzed the recent trends in income inequality, internal and international migrations and investigated the impact of migration on income distribution in Vietnam. Our analysis shows that the effects of migration on income inequality vary with different types of migration, depending on who migrate and where they migrate. Foreign remittances tend to flow toward more affluent households, and they increase income inequality. By contrast, domestic remittances accrue more to ...

  20. Pre- and post-displacement stressors and time of migration as related to self-rated health among Iraqi immigrants and refugees in Southeast Michigan.

    Science.gov (United States)

    Jamil, Hikmet; Nassar-McMillanb, Sylvia; Lambert, Richard; Wangd, Yun; Ager, Joel; Arnetz, Bengt

    2010-01-01

    The objective of this study was to determine whether perceived health status of Iraqi immigrants and refugees residing in the United States was related to pre-migration environmental stress, current unemployment, and if they had emigrated before or after the 1991 Gulf War. A random sample of Iraqis residing in Southeast Michigan, US, was interviewed using an Arab language structured survey. The main outcome measure was self-rated health (SRH). Major predictors included socioeconomics, employment status, pre-migration environmental stress, and health disorders. Path analysis was used to look at mediating effects between predictors and SRH. We found that SRH was significantly worse among participants that had left Iraq after the 1991 Gulf War. Unemployment and environmental stress exposure were inversely related to SRH. There was a direct path between Gulf War exposure and poor health. In addition, there were indirect paths mediated through psychosomatic and psychiatric disorders to SRH. Another path went from Gulf War exposure, via environmental stress and somatic health to poor health. Unemployment had a direct path, as well as indirect paths mediated through psychiatric and psychosomatic disorders, to poor self-rated health. In conclusion, these results suggest that pre- as well as post-migration factors, and period of migration, affect health.

  1. 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.

  2. 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

  3. Y-27632 Increases Sensitivity of PANC-1 Cells to Epigallocatechin Gallate (EGCG) in Regulating Cell Proliferation and Migration

    Science.gov (United States)

    Liu, Xing; Bi, Yongyi

    2016-01-01

    Background The study aimed to investigate the inhibitory effect of (1R,4r)-4-((R)-1-aminoethyl)-N-(pyridin-4-yl) cyclohexanecarboxamide (Y-27632) and (−)-epigallocatechin-3-gallate (EGCG) on the proliferation and migration of PANC-1 cells. EGCG, found in green tea, has been previously shown to be one of the most abundant and powerful catechins in cancer prevention and treatment. Y-27632, a selective inhibitor of rho-associated protein kinase 1, is widely used in treating cardiovascular disease, inflammation, and cancer. Material/Methods PANC-1 cells, maintained in Dulbecco’s Modified Eagle’s Medium, were treated with dimethyl sulfoxide (control) as well as different concentrations (20, 40, 60, and 80 μg/mL) of EGCG for 48 h. In addition, PANC-1 cells were treated separately with 60 μg/mL EGCG, 20 μM Y-27632, and EGCG combined with Y-27632 (60 μg/mL EGCG + 20 μM Y-27632) for 48 h. The effect of EGCG and Y-27632 on the proliferation and migration of PANC-1 cells was evaluated using Cell Counting Kit-8 and transwell migration assays. The expression of peroxisome proliferator–activated receptor alpha (PPARα) and Caspase-3 mRNA was determined by Quantitative real-time polymerase chain reaction (RT-qPCR). Results EGCG (20–80 μg/mL) inhibited cell viability in a dose-dependent manner. Y-27632 enhanced the sensitivity of PANC-1 cells to EGCG (by increasing the expression of PPARα and Caspase-3 mRNA) and suppressed cell proliferation. PANC-1 cell migration was inhibited by treatment with a combination of EGCG and Y-27632. Conclusions Y-27632 increases the sensitivity of PANC-1 cells to EGCG in regulating cell proliferation and migration, which is likely to be related to the expression of PPARα mRNA and Caspase-3 mRNA. PMID:27694793

  4. Patterns of gravity induced aggregate migration during casting of fluid concretes

    Energy Technology Data Exchange (ETDEWEB)

    Spangenberg, J. [Department of Mechanical Engineering, Technical University of Denmark (DTU) (Denmark); Roussel, N., E-mail: Nicolas.roussel@lcpc.fr [Universite Paris Est, Laboratoire Central des Ponts et Chaussees (LCPC) (France); Hattel, J.H. [Department of Mechanical Engineering, Technical University of Denmark (DTU) (Denmark); Sarmiento, E.V.; Zirgulis, G. [Department of Structural Engineering, Norwegian University of Science and Technology (NTNU) (Norway); Geiker, M.R. [Department of Structural Engineering, Norwegian University of Science and Technology (NTNU) (Norway); Department of Civil Engineering, Technical University of Denmark (DTU) (Denmark)

    2012-12-15

    In this paper, aggregate migration patterns during fluid concrete castings are studied through experiments, dimensionless approach and numerical modeling. The experimental results obtained on two beams show that gravity induced migration is primarily affecting the coarsest aggregates resulting in a decrease of coarse aggregates volume fraction with the horizontal distance from the pouring point and in a puzzling vertical multi-layer structure. The origin of this multi layer structure is discussed and analyzed with the help of numerical simulations of free surface flow. Our results suggest that it finds its origin in the non Newtonian nature of fresh concrete and that increasing casting rate shall decrease the magnitude of gravity induced particle migration.

  5. Patterns of gravity induced aggregate migration during casting of fluid concretes

    International Nuclear Information System (INIS)

    Spangenberg, J.; Roussel, N.; Hattel, J.H.; Sarmiento, E.V.; Zirgulis, G.; Geiker, M.R.

    2012-01-01

    In this paper, aggregate migration patterns during fluid concrete castings are studied through experiments, dimensionless approach and numerical modeling. The experimental results obtained on two beams show that gravity induced migration is primarily affecting the coarsest aggregates resulting in a decrease of coarse aggregates volume fraction with the horizontal distance from the pouring point and in a puzzling vertical multi-layer structure. The origin of this multi layer structure is discussed and analyzed with the help of numerical simulations of free surface flow. Our results suggest that it finds its origin in the non Newtonian nature of fresh concrete and that increasing casting rate shall decrease the magnitude of gravity induced particle migration.

  6. International migration patterns of physicians to the United States: a cross-national panel analysis.

    Science.gov (United States)

    Hussey, Peter S

    2007-12-01

    To analyze the dynamics of physician international migration patterns and identify the countries deviating most from expected migration rates. A negative binomial log-linear model of physician migration to the United States from every other country was constructed using a panel of country-level data for years 1994-2000. The model was used to identify factors associated with physician migration and to identify countries with higher or lower rates of physician migration than expected. Physician migration varied with a country's GDP per capita in an inverse-U pattern, with highest migration rates from middle-income countries. The absence of medical schools, immigrant networks in the United States, medical instruction in English, proximity to the United States, and the lack of political and civil liberties were also associated with higher migration rates. Countries with higher-than-predicted migration rates included Iceland, Albania, Armenia, Dominica, Lebanon, Syria, the United Arab Emirates, and Bulgaria. Countries with lower-than-predicted migration rates included Mexico, Japan, Brazil, Zimbabwe, Mauritania, Portugal, Senegal, and France. This analysis shows that many of the most powerful factors associated with physician migration are difficult or impossible for countries to change through public policy. GDP per capita and proximity to the U.S. are two of the most powerful predictors of physician migration. Networks of immigrants in the U.S. and fewer political and civil liberties also put countries at higher risk for physician emigration. Several other factors that were associated with physician migration might be more easily amenable to policy intervention. These factors include the absence of a medical school and medical instruction in English. Policies addressing these factors would involve making several difficult tradeoffs, however. Other examples of policies that are effective in minimizing physician migration might be found by examining countries with lower

  7. Testing thermal gradient driving force for grain boundary migration using molecular dynamics simulations

    International Nuclear Information System (INIS)

    Bai, Xian-Ming; Zhang, Yongfeng; Tonks, Michael R.

    2015-01-01

    Strong thermal gradients in low-thermal-conductivity ceramics may drive extended defects, such as grain boundaries and voids, to migrate in preferential directions. In this work, molecular dynamics simulations are conducted to study thermal gradient driven grain boundary migration and to verify a previously proposed thermal gradient driving force equation, using uranium dioxide as a model system. It is found that a thermal gradient drives grain boundaries to migrate up the gradient and the migration velocity increases under a constant gradient owing to the increase in mobility with temperature. Different grain boundaries migrate at very different rates due to their different intrinsic mobilities. The extracted mobilities from the thermal gradient driven simulations are compared with those calculated from two other well-established methods and good agreement between the three different methods is found, demonstrating that the theoretical equation of the thermal gradient driving force is valid, although a correction of one input parameter should be made. The discrepancy in the grain boundary mobilities between modeling and experiments is also discussed.

  8. 76 FR 29963 - Rate Increase Disclosure and Review

    Science.gov (United States)

    2011-05-23

    ... for the product associated with the rate increase; and (8) employee and executive compensation data... 154 Rate Increase Disclosure and Review; Final Rule #0;#0;Federal Register / Vol. 76 , No. 99 / Monday... CFR Part 154 [CMS-9999-FC] RIN 0938-AQ68 Rate Increase Disclosure and Review AGENCY: Center for...

  9. 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.

  10. SATB2 expression increased anchorage-independent growth and cell migration in human bronchial epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Feng; Jordan, Ashley; Kluz, Thomas [Department of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, NY 10987 (United States); Shen, Steven [Center for Health Informatics and Bioinformatics, New York University Langone Medical Center, New York, NY 10016 (United States); Sun, Hong; Cartularo, Laura A. [Department of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, NY 10987 (United States); Costa, Max, E-mail: Max.Costa@nyumc.org [Department of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, NY 10987 (United States)

    2016-02-15

    The special AT-rich sequence-binding protein 2 (SATB2) is a protein that binds to the nuclear matrix attachment region of the cell and regulates gene expression by altering chromatin structure. In our previous study, we reported that SATB2 gene expression was induced in human bronchial epithelial BEAS-2B cells transformed by arsenic, chromium, nickel and vanadium. In this study, we show that ectopic expression of SATB2 in the normal human bronchial epithelial cell-line BEAS-2B increased anchorage-independent growth and cell migration, meanwhile, shRNA-mediated knockdown of SATB2 significantly decreased anchorage-independent growth in Ni transformed BEAS-2B cells. RNA sequencing analyses of SATB2 regulated genes revealed the enrichment of those involved in cytoskeleton, cell adhesion and cell-movement pathways. Our evidence supports the hypothesis that SATB2 plays an important role in BEAS-2B cell transformation. - Highlights: • We performed SATB2 overexpression in the BEAS-2B cell line. • We performed SATB2 knockdown in a Ni transformed BEAS-2B cell line. • SATB2 induced anchorage-independent growth and increased cell migration. • SATB2 knockdown significantly decreased anchorage-independent growth. • We identified alterations in gene involved in cytoskeleton, cell adhesion.

  11. SATB2 expression increased anchorage-independent growth and cell migration in human bronchial epithelial cells

    International Nuclear Information System (INIS)

    Wu, Feng; Jordan, Ashley; Kluz, Thomas; Shen, Steven; Sun, Hong; Cartularo, Laura A.; Costa, Max

    2016-01-01

    The special AT-rich sequence-binding protein 2 (SATB2) is a protein that binds to the nuclear matrix attachment region of the cell and regulates gene expression by altering chromatin structure. In our previous study, we reported that SATB2 gene expression was induced in human bronchial epithelial BEAS-2B cells transformed by arsenic, chromium, nickel and vanadium. In this study, we show that ectopic expression of SATB2 in the normal human bronchial epithelial cell-line BEAS-2B increased anchorage-independent growth and cell migration, meanwhile, shRNA-mediated knockdown of SATB2 significantly decreased anchorage-independent growth in Ni transformed BEAS-2B cells. RNA sequencing analyses of SATB2 regulated genes revealed the enrichment of those involved in cytoskeleton, cell adhesion and cell-movement pathways. Our evidence supports the hypothesis that SATB2 plays an important role in BEAS-2B cell transformation. - Highlights: • We performed SATB2 overexpression in the BEAS-2B cell line. • We performed SATB2 knockdown in a Ni transformed BEAS-2B cell line. • SATB2 induced anchorage-independent growth and increased cell migration. • SATB2 knockdown significantly decreased anchorage-independent growth. • We identified alterations in gene involved in cytoskeleton, cell adhesion.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

    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. (letter)

  13. Migration, pastoralists, HIV infection and access to care: the ...

    African Journals Online (AJOL)

    The burden of HIV infection among the nomadic Fulani of northern Nigeria is unknown. Migration — a way of life for this population — is known to increase the rate of HIV transmission and may limit individuals' access to treatment and care. Many of Africa's other traditional, pastoral societies are similarly affected. This paper ...

  14. Antioxidant migration resistance of SiOx layer 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.

  15. Increased asthma and adipose tissue inflammatory gene expression with obesity and Inuit migration to a western country

    DEFF Research Database (Denmark)

    Backer, Vibeke; Baines, Katherine J; Powell, Heather

    2016-01-01

    inflammation can be modified by migration and diet. OBJECTIVE: To examine mast cell and inflammatory markers in adipose tissue and the association with asthma. METHODS: Two Inuit populations were recruited, one living in Greenland and another in Denmark. All underwent adipose subcutaneous biopsy, followed...... of mast cell markers in adipose tissue and asthma. Among Greenlandic Inuit, adipose tissue inflammation is also increased in those who migrate to Denmark, possibly as a result of dietary changes....... by clinical assessment of asthma, and measurement of AHR. Adipose tissue biopsies were homogenised, RNA extracted, and PCR was performed to determine the relative gene expression of mast cell (tryptase, chymase, CPA3) and inflammatory markers (IL-6, IL-1β, and CD163). RESULTS: Of the 1059 Greenlandic Inuit...

  16. 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

    for the application of migration velocity analysis. We are interested in particular in an important problem: the influence of irregularities in seismic acquisition on the quality of the depth migrated images. Indeed, 3-D seismic acquisitions show irregularities which are characterized by offset variations as well as a non uniform spatial sampling of the data. To overcome the first kind of irregularities, we propose to introduce the concept of migration by offset class in which are migrated all seismic traces that belong to a given offset class, and we show that such a migration relies on a sound theoretical basis whenever the offset varies smoothly with the midpoint coordinate. These theoretical considerations are validated experimentally: offset classes constructed so that the offset varies slowly with the midpoint coordinate allow to obtain the required imaging quality for migration velocity analysis. The influence, on the quality of the migrated images, of a non uniform spatial sampling of the data is, as for it, much more important than the one linked to offset variations: the computation of the superposition of migrated images associated with each midpoint requires the use of a genuine numerical integration formula. We study quadrature formulas based on polynomial interpolation procedures of the function to be integrated. We recommend to use the Hermite interpolation based numerical integration formula if we are primarily interested in amplitude variations in the case of gently dipping layers, and the Lagrange interpolation based numerical integration formula for the imaging of structures involving some complexity. Moreover, the implementation of these schemes of interpolation consists of a preprocessing of the data and does not really increase the CPU time required for running the migration itself. Of course, these approaches require that the distribution of midpoints is dense enough so as to take correctly into account the variations of the function to be

  17. Migration of accreting giant planets

    Science.gov (United States)

    Robert, C.; Crida, A.; Lega, E.; Méheut, H.

    2017-09-01

    Giant planets forming in protoplanetary disks migrate relative to their host star. By repelling the gas in their vicinity, they form gaps in the disk's structure. If they are effectively locked in their gap, it follows that their migration rate is governed by the accretion of the disk itself onto the star, in a so-called type II fashion. Recent results showed however that a locking mechanism was still lacking, and was required to understand how giant planets may survive their disk. We propose that planetary accretion may play this part, and help reach this slow migration regime.

  18. Dependence of EGF-Induced Increases in Corneal Epithelial Proliferation and Migration on GSK-3 Inactivation

    Science.gov (United States)

    2009-10-01

    during epidermal growth factor-stimulated actin nucleation in breast cancer cells. J Biol Chem. 2000;275:3741–3744. 27. Jope RS, Johnson GV. The...injury-induced corneal epi- thelial wound closure.1,2 This cytokine induces increases in cell proliferation and migration through activation of its cog ...occurs between the PI3-K and the ERK pathways in colon cancer cell lines.12 Without a cytokine, GSK-3 is dephosphorylated and constitutively active

  19. 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.

  20. 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.

  1. Migration signatures across the decades: Net migration by age in U.S. counties, 1950-2010

    Directory of Open Access Journals (Sweden)

    Richelle L. Winkler

    2015-05-01

    Full Text Available Background: Migration is the primary population redistribution process in the United States. Selective migration by age, race/ethnic group, and spatial location governs population integration, affects community and economic development, contributes to land use change, and structures service needs. Objective: Delineate historical net migration patterns by age, race/ethnic, and rural-urban dimensions for United States counties. Methods: Net migration rates by age for all US counties are aggregated from 1950−2010, summarized by rural-urban location and compared to explore differential race/ethnic patterns of age-specific net migration over time. Results: We identify distinct age-specific net migration 'signatures' that are consistent over time within county types, but different by rural-urban location and race/ethnic group. There is evidence of moderate population deconcentration and diminished racial segregation between 1990 and 2010. This includes a net outflow of Blacks from large urban core counties to suburban and smaller metropolitan counties, continued Hispanic deconcentration, and a slowdown in White counterurbanization. Conclusions: This paper contributes to a fuller understanding of the complex patterns of migration that have redistributed the U.S. population over the past six decades. It documents the variability in county age-specific net migration patterns both temporally and spatially, as well as the longitudinal consistency in migration signatures among county types and race/ethnic groups.

  2. Protein electrophoretic migration data from custom and commercial gradient gels

    Directory of Open Access Journals (Sweden)

    Andrew J. Miller

    2016-12-01

    Full Text Available This paper presents data related to the article “A method for easily customizable gradient gel electrophoresis” (A.J. Miller, B. Roman, E.M. Norstrom, 2016 [1]. Data is presented on the rate of electrophoretic migration of proteins in both hand-poured and commercially acquired acrylamide gradient gels. For each gel, migration of 9 polypeptides of various masses was measured upon completion of gel electrophoresis. Data are presented on the migration of proteins within separate lanes of the same gel as well as migration rates from multiple gels.

  3. Internal migration in Mexico and its determinants

    Directory of Open Access Journals (Sweden)

    Rogelio Varela Llamas

    2016-12-01

    Full Text Available This paper presents an analysis of internal migration in Mexico. Using micro data from the National Survey on Occupation and Employment (enoe, we estimate a multinomial logit model for the case of intrastate and interstate migration. We also conduct estimations for municipalities of different sizes. The results suggest that the probability of migrating increases with the number of weeks spent searching for a job, regardless of whether the search is conducted while the individual is employed or unemployed. In addition, we find that as the number of hours of work per week increases, the probability of migrating rises. The search process does not increase the probability of migrating in rural communities as it does in urban centers.

  4. Migration of polypotent hemopoietic stem cells from mouse bone marrow shielded during irradiation after hemorrhage and transfusion of syngeneic erythrocytes

    International Nuclear Information System (INIS)

    Kozlov, V.A.; Lozovoj, V.P.; Zhuravkin, I.N.

    1977-01-01

    CBA mice have been X-irradiated with a lethal dose of 850 R. The rate of migration of hemopoietic stem cells has been studied at varying times after hemorrhage and administration of syngeneic erythrocytes. Hemorrhage has been shown to enhance markedly the stem cell migration. Administration of syngeneic erythrocytes decreases considerably the rate of stem cell migaration. It is suggested that the erythropoiesis stimulation is responsible for the increased yield of stem cells from the bone marrow, and that the suppression of erythropoiesis inhibits migration of the stem cells

  5. Increasing Running Step Rate Reduces Patellofemoral Joint Forces

    Science.gov (United States)

    Lenhart, Rachel L.; Thelen, Darryl G.; Wille, Christa M.; Chumanov, Elizabeth S.; Heiderscheit, Bryan C.

    2013-01-01

    Purpose Increasing step rate has been shown to elicit changes in joint kinematics and kinetics during running, and has been suggested as a possible rehabilitation strategy for runners with patellofemoral pain. The purpose of this study was to determine how altering step rate affects internal muscle forces and patellofemoral joint loads, and then to determine what kinematic and kinetic factors best predict changes in joint loading. Methods We recorded whole body kinematics of 30 healthy adults running on an instrumented treadmill at three step rate conditions (90%, 100%, and 110% of preferred step rate). We then used a 3D lower extremity musculoskeletal model to estimate muscle, patellar tendon, and patellofemoral joint forces throughout the running gait cycles. Additionally, linear regression analysis allowed us to ascertain the relative influence of limb posture and external loads on patellofemoral joint force. Results Increasing step rate to 110% of preferred reduced peak patellofemoral joint force by 14%. Peak muscle forces were also altered as a result of the increased step rate with hip, knee and ankle extensor forces, and hip abductor forces all reduced in mid-stance. Compared to the 90% step rate condition, there was a concomitant increase in peak rectus femoris and hamstring loads during early and late swing, respectively, at higher step rates. Peak stance phase knee flexion decreased with increasing step rate, and was found to be the most important predictor of the reduction in patellofemoral joint loading. Conclusion Increasing step rate is an effective strategy to reduce patellofemoral joint forces and could be effective in modulating biomechanical factors that can contribute to patellofemoral pain. PMID:23917470

  6. Gender-specific out-migration, deforestation and urbanization in the Ecuadorian Amazon

    Science.gov (United States)

    Barbieri, Alisson F.; Carr, David L.

    2005-07-01

    The Ecuadorian Amazon, one of the richest reserves of biodiversity in the world, has faced one of the highest rates of deforestation of any Amazonian nation. Most of this forest elimination has been caused by agricultural colonization that followed the discovery of oil fields in 1967. Since the 1990s, an increasing process of urbanization has also engendered new patterns of population mobility within the Amazon, along with traditional ways by which rural settlers make their living. However, while very significant in its effects on deforestation, urbanization and regional development, population mobility within the Amazon has hardly been studied at all, as well as the distinct migration patterns between men and women. This paper uses a longitudinal dataset of 250 farm households in the Northern Ecuadorian Amazon to understand differentials between men and women migrants to urban and rural destinations and between men and women non-migrants. First, we use hazard analysis based on the Kaplan-Meier (KM) estimator to obtain the cumulative probability that an individual living in the study area in 1990 or at time t, will out-migrated at some time, t+ n, before 1999. Results indicate that out-migration to other rural areas in the Amazon, especially pristine areas is considerably greater than out-migration to the growing, but still incipient, Amazonian urban areas. Furthermore, men are more likely to out-migrate to rural areas than women, while the reverse occurs for urban areas. Difference-of-means tests were employed to examine potential factors accounting for differentials between male and female out-migration to urban and rural areas. Among the key results, relative to men younger women are more likely to out-migrate to urban areas; more difficult access from farms to towns and roads constrains women's migration; and access to new lands in the Amazon-an important cause of further deforestation-is more associated with male out-migration. Economic factors such as

  7. Small flow rate can supply inwardly migrating shortest-period planets

    Directory of Open Access Journals (Sweden)

    Taylor S.F.

    2013-04-01

    Full Text Available The number of exoplanets found with periods as short as one day and less was surprising given how fast these planets had been expected to migrate into the star due to the tides raised on the star by planets at such close distances. It has been seen as improbable that we would find planets in such a small final fraction of their lives [1]. The favored solution has been that the tidal dissipation is much weaker than expected, which would mean that the final infall would be a larger fraction of the planets’ life. We find no reason, however, to exclude the explanation that a small number of planets are continuously sent migrating inwards such that these planets indeed are in the last fraction of their lives. Following the observation that the distribution of medium planets disfavors tidal dissipation being significantly weaker than has been found from observations of binary stars [2], we now show that the numbers of planets in such a “flow” of excess planets migrating inwards is low enough that even depletion of the three-day pileup is a plausible source. Then the shortest period occurrence distribution would be shaped by planets continuously being sent into the star, which may explain the depletion of the pileup in the Kepler field relative to the solar neighborhood [3]. Because Kepler observes above the galactic plan, [3] suggested the Kepler field may include an older population of stars. The tidal dissipation strength in stars due to giant planets may be not greatly weaker than it is in binary stars.

  8. Numerical examination of the factors controlling DNAPL migration through a single fracture.

    Science.gov (United States)

    Reynolds, D A; Kueper, B H

    2002-01-01

    The migration of five dense nonaqueous phase liquids (DNAPLs) through a single fracture in a clay aquitard was numerically simulated with the use of a compositional simulator. The effects of fracture aperture, fracture dip, matrix porosity, and matrix organic carbon content on the migration of chlorobenzene, 1,2-dichloroethylene, trichloroethylene, tetra-chloroethylene, and 1,2-dibromoethane were examined. Boundary conditions were chosen such that DNAPL entry into the system was allowed to vary according to the stresses applied. The aperture is the most important factor of those studied controlling the migration rate of DNAPL through a single fracture embedded in a clay matrix. Loss of mass to the matrix through diffusion does not significantly retard the migration rate of the DNAPL, particularly in larger aperture fractures (e.g., 50 microm). With time, the ratio of diffusive loss to the matrix to DNAPL flux into the fracture approaches an asymptotic value lower than unity. The implication is that matrix diffusion cannot arrest the migration of DNAPL in a single fracture. The complex relationships between density, viscosity, and solubility that, to some extent, govern the migration of DNAPL through these systems prevent accurate predictions without the use of numerical models. The contamination potential of the migrating DNAPL is significantly increased through the transfer of mass to the matrix. The occurrence of opposite concentration gradients within the matrix can cause dissolved phase contamination to exist in the system for more than 1000 years after the DNAPL has been completely removed from the fracture.

  9. Networks Versus Need: Drivers of Urban Out-Migration in the Brazilian Amazon.

    Science.gov (United States)

    Randell, Heather F; VanWey, Leah K

    2014-12-01

    As urbanization rates rise globally, it becomes increasingly important to understand the factors associated with urban out-migration. In this paper, we examine the drivers of urban out-migration among young adults in two medium-sized cities in the Brazilian Amazon-Altamira and Santarém-focusing on the roles of social capital, human capital, and socioeconomic deprivation. Using household survey data from 1,293 individuals in the two cities, we employ an event history model to assess factors associated with migration and a binary logit model to understand factors associated with remitting behavior. We find that in Altamira, migration tends to be an individual-level opportunistic strategy fostered by extra-local family networks, while in Santarém, migration tends to be a household-level strategy driven by socioeconomic deprivation and accompanied by remittances. These results indicate that urban out-migration in Brazil is a diverse social process, and that the relative roles of extra-local networks versus economic need can function quite differently between geographically proximate but historically and socioeconomically distinct cities.

  10. GABA regulates the multidirectional tangential migration of GABAergic interneurons in living neonatal mice.

    Directory of Open Access Journals (Sweden)

    Hiroyuki Inada

    Full Text Available Cortical GABAergic interneurons originate from ganglionic eminences and tangentially migrate into the cortical plate at early developmental stages. To elucidate the characteristics of this migration of GABAergic interneurons in living animals, we established an experimental design specialized for in vivo time-lapse imaging of the neocortex of neonate mice with two-photon laser-scanning microscopy. In vesicular GABA/glycine transporter (VGAT-Venus transgenic mice from birth (P0 through P3, we observed multidirectional tangential migration of genetically-defined GABAergic interneurons in the neocortical marginal zone. The properties of this migration, such as the motility rate (distance/hr, the direction moved, and the proportion of migrating neurons to stationary neurons, did not change through P0 to P3, although the density of GABAergic neurons at the marginal zone decreased with age. Thus, the characteristics of the tangential motility of individual GABAergic neurons remained constant in development. Pharmacological block of GABA(A receptors and of the Na⁺-K⁺-Cl⁻ cotransporters, and chelating intracellular Ca²⁺, all significantly reduced the motility rate in vivo. The motility rate and GABA content within the cortex of neonatal VGAT-Venus transgenic mice were significantly greater than those of GAD67-GFP knock-in mice, suggesting that extracellular GABA concentration could facilitate the multidirectional tangential migration. Indeed, diazepam applied to GAD67-GFP mice increased the motility rate substantially. In an in vitro neocortical slice preparation, we confirmed that GABA induced a NKCC sensitive depolarization of GABAergic interneurons in VGAT-Venus mice at P0-P3. Thus, activation of GABA(AR by ambient GABA depolarizes GABAergic interneurons, leading to an acceleration of their multidirectional motility in vivo.

  11. Adjusting the general growth balance method for migration

    OpenAIRE

    Hill, Kenneth; Queiroz, Bernardo

    2010-01-01

    Death distribution methods proposed for death registration coverage by comparison with census age distributions assume no net migration. This assumption makes it problematic to apply these methods to sub-national and national populations affected by substantial net migration. In this paper, we propose and explore a two-step process in which the Growth Balance Equation is first used to estimate net migration rates, using a model of age-specific migration, and then it is used to compare the obs...

  12. Gas Bubble Migration and Trapping in Porous Media: Pore-Scale Simulation

    Science.gov (United States)

    Mahabadi, Nariman; Zheng, Xianglei; Yun, Tae Sup; van Paassen, Leon; Jang, Jaewon

    2018-02-01

    Gas bubbles can be naturally generated or intentionally introduced in sediments. Gas bubble migration and trapping affect the rate of gas emission into the atmosphere or modify the sediment properties such as hydraulic and mechanical properties. In this study, the migration and trapping of gas bubbles are simulated using the pore-network model extracted from the 3D X-ray image of in situ sediment. Two types of bubble size distribution (mono-sized and distributed-sized cases) are used in the simulation. The spatial and statistical bubble size distribution, residual gas saturation, and hydraulic conductivity reduction due to the bubble trapping are investigated. The results show that the bubble size distribution becomes wider during the gas bubble migration due to bubble coalescence for both mono-sized and distributed-sized cases. And the trapped bubble fraction and the residual gas saturation increase as the bubble size increases. The hydraulic conductivity is reduced as a result of the gas bubble trapping. The reduction in hydraulic conductivity is apparently observed as bubble size and the number of nucleation points increase.

  13. Are rates of pediatric bipolar disorder increasing?

    DEFF Research Database (Denmark)

    Kessing, Lars Vedel; Vradi, Eleni; Andersen, Per Kragh

    2014-01-01

    Studies from the USA suggest that rates of pediatric bipolar disorder have increased since the mid-90s, but no study outside the USA has been published on the rates of pediatric bipolar disorder. Further, it is unclear whether an increase in rates reflects a true increase in the illness or more...... diagnostic attention. Using nationwide registers of all inpatients and outpatients contacts to all psychiatric hospitals in Denmark, we investigated (1) gender-specific rates of incident pediatric mania/bipolar disorder during a period from 1995 to 2012, (2) whether age and other characteristics...... for pediatric mania/bipolar disorder changed during the calendar period (1995 to 2003 versus 2004 to 2012), and (3) whether the diagnosis is more often made at first psychiatric contact in recent time compared to earlier according to gender. Totally, 346 patients got a main diagnosis of a manic episode (F30...

  14. THE MIGRATION SITUATION IN THE CAPITAL MEGAPOLIS: PROBLEMS AND PROSPECTS

    Directory of Open Access Journals (Sweden)

    E. N. Novoselova

    2016-01-01

    Full Text Available The article is dedicated to one of the most pressing problems of our time — migration. Depopulation, population ageing, falling birth rate among the indigenous population creates conditions when migration becomes one of the most important sources of population growth in developed countries. Despite the fact that the problems depopulation can’t be solved only through migration, it is impossible to manage the situation without migrants, otherwise population will decline even more rapidly. The article analyzes particularities of migration in Russia, especially focusing on migration in Moscow. The main emphasis is made on the problems of interaction between migrants and the host community, or more precisely on the attitudes towards migrants among Muscovites. There is a high level of anti-immigrant and xenophobic attitudes among Moscow’s residents, which points to the necessity to overcome migrantophobia, promote tolerance, establish cultural dialogue between migrants and the indigenous population of the region. Negative consequences of xenophobia are analyzed, which pose a threat to Russian stability and security. A lot of attention is paid to such feature of contemporary migration as the increasing proportion of women among migrants — the feminization of migration, problems and prospects that follow it. In conclusions, the author relies on the existing statistical data, as well as the results of sociological research, conducted both on the national and regional levels. 

  15. MIGRATION OF EXTRASOLAR PLANETS: EFFECTS FROM X-WIND ACCRETION DISKS

    International Nuclear Information System (INIS)

    Adams, Fred C.; Cai, Mike J.; Lizano, Susana

    2009-01-01

    Magnetic fields are dragged in from the interstellar medium during the gravitational collapse that forms star/disk systems. Consideration of mean field magnetohydrodynamics in these disks shows that magnetic effects produce sub-Keplerian rotation curves and truncate the inner disk. This Letter explores the ramifications of these predicted disk properties for the migration of extrasolar planets. Sub-Keplerian flow in gaseous disks drives a new migration mechanism for embedded planets and modifies the gap-opening processes for larger planets. This sub-Keplerian migration mechanism dominates over Type I migration for sufficiently small planets (m P ∼ + ) and/or close orbits (r ∼< 1 AU). Although the inclusion of sub-Keplerian torques shortens the total migration time by only a moderate amount, the mass accreted by migrating planetary cores is significantly reduced. Truncation of the inner disk edge (for typical system parameters) naturally explains final planetary orbits with periods P ∼ 4 days. Planets with shorter periods, P ∼ 2 days, can be explained by migration during FU-Orionis outbursts, when the mass accretion rate is high and the disk edge moves inward. Finally, the midplane density is greatly increased at the inner truncation point of the disk (the X-point); this enhancement, in conjunction with continuing flow of gas and solids through the region, supports the in situ formation of giant planets.

  16. A note on migration with borrowing constraints.

    Science.gov (United States)

    Ghatak, S; Levine, P

    1994-12-01

    "This note examines an important conflict between the theory and evidence on migration in LDCs. While the Harris-Todaro class of models explain the phenomenon of migration mainly by expected income differential between the economically advanced and the backward regions, the actual evidence in some cases suggests that migration could actually rise following a rise in income in backward areas. We resolve this puzzle by analysing migration in the context of the existence of imperfect credit markets in LDCs. We show that under certain plausible conditions, the rate of migration from the rural to the urban areas may actually rise when rural wages rise, as they ease the constraints on borrowing by potential migrants." excerpt

  17. 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.

  18. Proteolytic Enzymes Clustered in Specialized Plasma-Membrane Domains Drive Endothelial Cells' Migration.

    Directory of Open Access Journals (Sweden)

    Monica Salamone

    Full Text Available In vitro cultured endothelial cells forming a continuous monolayer establish stable cell-cell contacts and acquire a "resting" phenotype; on the other hand, when growing in sparse conditions these cells acquire a migratory phenotype and invade the empty area of the culture. Culturing cells in different conditions, we compared expression and clustering of proteolytic enzymes in cells having migratory versus stationary behavior. In order to observe resting and migrating cells in the same microscopic field, a continuous cell monolayer was wounded. Increased expression of proteolytic enzymes was evident in cell membranes of migrating cells especially at sprouting sites and in shed membrane vesicles. Gelatin zymography and western blotting analyses confirmed that in migrating cells, expression of membrane-bound and of vesicle-associated proteolytic enzymes are increased. The enzymes concerned include MMP-2, MMP-9, MT1-MMP, seprase, DPP4 (DiPeptidyl Peptidase 4 and uPA. Shed membrane vesicles were shown to exert degradative activity on ECM components and produce substrates facilitating cell migration. Vesicles shed by migrating cells degraded ECM components at an increased rate; as a result their effect on cell migration was amplified. Inhibiting either Matrix Metallo Proteases (MMPs or Serine Integral Membrane Peptidases (SIMPs caused a decrease in the stimulatory effect of vesicles, inhibiting the spontaneous migratory activity of cells; a similar result was also obtained when a monoclonal antibody acting on DPP4 was tested. We conclude that proteolytic enzymes have a synergistic stimulatory effect on cell migration and that their clustering probably facilitates the proteolytic activation cascades needed to produce maximal degradative activity on cell substrates during the angiogenic process.

  19. Proteolytic Enzymes Clustered in Specialized Plasma-Membrane Domains Drive Endothelial Cells' Migration.

    Science.gov (United States)

    Salamone, Monica; Carfì Pavia, Francesco; Ghersi, Giulio

    2016-01-01

    In vitro cultured endothelial cells forming a continuous monolayer establish stable cell-cell contacts and acquire a "resting" phenotype; on the other hand, when growing in sparse conditions these cells acquire a migratory phenotype and invade the empty area of the culture. Culturing cells in different conditions, we compared expression and clustering of proteolytic enzymes in cells having migratory versus stationary behavior. In order to observe resting and migrating cells in the same microscopic field, a continuous cell monolayer was wounded. Increased expression of proteolytic enzymes was evident in cell membranes of migrating cells especially at sprouting sites and in shed membrane vesicles. Gelatin zymography and western blotting analyses confirmed that in migrating cells, expression of membrane-bound and of vesicle-associated proteolytic enzymes are increased. The enzymes concerned include MMP-2, MMP-9, MT1-MMP, seprase, DPP4 (DiPeptidyl Peptidase 4) and uPA. Shed membrane vesicles were shown to exert degradative activity on ECM components and produce substrates facilitating cell migration. Vesicles shed by migrating cells degraded ECM components at an increased rate; as a result their effect on cell migration was amplified. Inhibiting either Matrix Metallo Proteases (MMPs) or Serine Integral Membrane Peptidases (SIMPs) caused a decrease in the stimulatory effect of vesicles, inhibiting the spontaneous migratory activity of cells; a similar result was also obtained when a monoclonal antibody acting on DPP4 was tested. We conclude that proteolytic enzymes have a synergistic stimulatory effect on cell migration and that their clustering probably facilitates the proteolytic activation cascades needed to produce maximal degradative activity on cell substrates during the angiogenic process.

  20. Proteolytic Enzymes Clustered in Specialized Plasma-Membrane Domains Drive Endothelial Cells’ Migration

    Science.gov (United States)

    Salamone, Monica; Carfì Pavia, Francesco

    2016-01-01

    In vitro cultured endothelial cells forming a continuous monolayer establish stable cell-cell contacts and acquire a “resting” phenotype; on the other hand, when growing in sparse conditions these cells acquire a migratory phenotype and invade the empty area of the culture. Culturing cells in different conditions, we compared expression and clustering of proteolytic enzymes in cells having migratory versus stationary behavior. In order to observe resting and migrating cells in the same microscopic field, a continuous cell monolayer was wounded. Increased expression of proteolytic enzymes was evident in cell membranes of migrating cells especially at sprouting sites and in shed membrane vesicles. Gelatin zymography and western blotting analyses confirmed that in migrating cells, expression of membrane-bound and of vesicle-associated proteolytic enzymes are increased. The enzymes concerned include MMP-2, MMP-9, MT1-MMP, seprase, DPP4 (DiPeptidyl Peptidase 4) and uPA. Shed membrane vesicles were shown to exert degradative activity on ECM components and produce substrates facilitating cell migration. Vesicles shed by migrating cells degraded ECM components at an increased rate; as a result their effect on cell migration was amplified. Inhibiting either Matrix Metallo Proteases (MMPs) or Serine Integral Membrane Peptidases (SIMPs) caused a decrease in the stimulatory effect of vesicles, inhibiting the spontaneous migratory activity of cells; a similar result was also obtained when a monoclonal antibody acting on DPP4 was tested. We conclude that proteolytic enzymes have a synergistic stimulatory effect on cell migration and that their clustering probably facilitates the proteolytic activation cascades needed to produce maximal degradative activity on cell substrates during the angiogenic process. PMID:27152413

  1. Aging increases microglial proliferation, delays cell migration, and decreases cortical neurogenesis after focal cerebral ischemia.

    Science.gov (United States)

    Moraga, Ana; Pradillo, Jesús M; García-Culebras, Alicia; Palma-Tortosa, Sara; Ballesteros, Ivan; Hernández-Jiménez, Macarena; Moro, María A; Lizasoain, Ignacio

    2015-05-10

    Aging is not just a risk factor of stroke, but it has also been associated with poor recovery. It is known that stroke-induced neurogenesis is reduced but maintained in the aged brain. However, there is no consensus on how neurogenesis is affected after stroke in aged animals. Our objective is to determine the role of aging on the process of neurogenesis after stroke. We have studied neurogenesis by analyzing proliferation, migration, and formation of new neurons, as well as inflammatory parameters, in a model of cerebral ischemia induced by permanent occlusion of the middle cerebral artery in young- (2 to 3 months) and middle-aged mice (13 to 14 months). Aging increased both microglial proliferation, as shown by a higher number of BrdU(+) cells and BrdU/Iba1(+) cells in the ischemic boundary and neutrophil infiltration. Interestingly, aging increased the number of M1 monocytes and N1 neutrophils, consistent with pro-inflammatory phenotypes when compared with the alternative M2 and N2 phenotypes. Aging also inhibited (subventricular zone) SVZ cell proliferation by decreasing both the number of astrocyte-like type-B (prominin-1(+)/epidermal growth factor receptor (EGFR)(+)/nestin(+)/glial fibrillary acidic protein (GFAP)(+) cells) and type-C cells (prominin-1(+)/EGFR(+)/nestin(-)/Mash1(+) cells), and not affecting apoptosis, 1 day after stroke. Aging also inhibited migration of neuroblasts (DCX(+) cells), as indicated by an accumulation of neuroblasts at migratory zones 14 days after injury; consistently, aged mice presented a smaller number of differentiated interneurons (NeuN(+)/BrdU(+) and GAD67(+) cells) in the peri-infarct cortical area 14 days after stroke. Our data confirm that stroke-induced neurogenesis is maintained but reduced in aged animals. Importantly, we now demonstrate that aging not only inhibits proliferation of specific SVZ cell subtypes but also blocks migration of neuroblasts to the damaged area and decreases the number of new interneurons in

  2. 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.

  3. 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

  4. IL-6 is increased in the cerebellum of autistic brain and alters neural cell adhesion, migration and synaptic formation.

    Science.gov (United States)

    Wei, Hongen; Zou, Hua; Sheikh, Ashfaq M; Malik, Mazhar; Dobkin, Carl; Brown, W Ted; Li, Xiaohong

    2011-05-19

    Although the cellular mechanisms responsible for the pathogenesis of autism are not understood, a growing number of studies have suggested that localized inflammation of the central nervous system (CNS) may contribute to the development of autism. Recent evidence shows that IL-6 has a crucial role in the development and plasticity of CNS. Immunohistochemistry studies were employed to detect the IL-6 expression in the cerebellum of study subjects. In vitro adenoviral gene delivery approach was used to over-express IL-6 in cultured cerebellar granule cells. Cell adhesion and migration assays, DiI labeling, TO-PRO-3 staining and immunofluorescence were used to examine cell adhesion and migration, dendritic spine morphology, cell apoptosis and synaptic protein expression respectively. In this study, we found that IL-6 was significantly increased in the cerebellum of autistic subjects. We investigated how IL-6 affects neural cell development and function by transfecting cultured mouse cerebellar granule cells with an IL-6 viral expression vector. We demonstrated that IL-6 over-expression in granule cells caused impairments in granule cell adhesion and migration but had little effect on the formation of dendritic spines or granule cell apoptosis. However, IL-6 over-expression stimulated the formation of granule cell excitatory synapses, without affecting inhibitory synapses. Our results provide further evidence that aberrant IL-6 may be associated with autism. In addition, our results suggest that the elevated IL-6 in the autistic brain could alter neural cell adhesion, migration and also cause an imbalance of excitatory and inhibitory circuits. Thus, increased IL-6 expression may be partially responsible for the pathogenesis of autism.

  5. IL-6 is increased in the cerebellum of autistic brain and alters neural cell adhesion, migration and synaptic formation

    Directory of Open Access Journals (Sweden)

    Dobkin Carl

    2011-05-01

    Full Text Available Abstract Background Although the cellular mechanisms responsible for the pathogenesis of autism are not understood, a growing number of studies have suggested that localized inflammation of the central nervous system (CNS may contribute to the development of autism. Recent evidence shows that IL-6 has a crucial role in the development and plasticity of CNS. Methods Immunohistochemistry studies were employed to detect the IL-6 expression in the cerebellum of study subjects. In vitro adenoviral gene delivery approach was used to over-express IL-6 in cultured cerebellar granule cells. Cell adhesion and migration assays, DiI labeling, TO-PRO-3 staining and immunofluorescence were used to examine cell adhesion and migration, dendritic spine morphology, cell apoptosis and synaptic protein expression respectively. Results In this study, we found that IL-6 was significantly increased in the cerebellum of autistic subjects. We investigated how IL-6 affects neural cell development and function by transfecting cultured mouse cerebellar granule cells with an IL-6 viral expression vector. We demonstrated that IL-6 over-expression in granule cells caused impairments in granule cell adhesion and migration but had little effect on the formation of dendritic spines or granule cell apoptosis. However, IL-6 over-expression stimulated the formation of granule cell excitatory synapses, without affecting inhibitory synapses. Conclusions Our results provide further evidence that aberrant IL-6 may be associated with autism. In addition, our results suggest that the elevated IL-6 in the autistic brain could alter neural cell adhesion, migration and also cause an imbalance of excitatory and inhibitory circuits. Thus, increased IL-6 expression may be partially responsible for the pathogenesis of autism.

  6. Questions of migration and belonging: understandings of migration under neoliberalism in Ecuador.

    Science.gov (United States)

    Lawson, V

    1999-01-01

    This paper explores alternative understandings and experiences of migration under neoliberalism in Ecuador. Through the case study, the study examines migrants' multiple motivations for mobility and their ambivalence toward the process. Insights from the transnational migration literature were drawn in order to think through the implications of an increasingly contradictory context of economic modernization and its impact upon the sense of possibilities and belonging of migrants. In-depth interviews with urban-destined migrants in Ecuador were drawn to argue that mobility produces ambivalent development subjects. This argument is developed in three sections. First, the paper centers on the epistemological and theoretical basis for the relevance of migrant narratives in extending theorizations of migration. Second, in-depth interviews with migrants to Quito are drawn to explore migrants' sense of belonging and regional affiliation, identity formation through migration, and experiences of alienation and disruption in their lives. Lastly, this paper concludes with a retheorization of the role of migration places in the migrant identity construction.

  7. RSA migration of total knee replacements.

    Science.gov (United States)

    Pijls, Bart G; Plevier, José W M; Nelissen, Rob G H H

    2018-06-01

    Purpose - We performed a systematic review and meta-analyses to evaluate the early and long-term migration patterns of tibial components of TKR of all known RSA studies. Methods - Migration pattern was defined as at least 2 postoperative RSA follow-up moments. Maximal total point motion (MTPM) at 6 weeks, 3 months, 6 months, 1 year, 2 years, 5 years, and 10 years were considered. Results - The literature search yielded 1,167 hits of which 53 studies were included, comprising 111 study groups and 2,470 knees. The majority of the early migration occurred in the first 6 months postoperatively followed by a period of stability, i.e., no or very little migration. Cemented and uncemented tibial components had different migration patterns. For cemented tibial components there was no difference in migration between all-poly and metal-backed components, between mobile bearing and fixed bearing, between cruciate retaining and posterior stabilized. Furthermore, no difference existed between TKR measured with model-based RSA or marker-based RSA methods. For uncemented TKR there was some variation in migration with the highest migration for uncoated TKR. Interpretation - The results from this meta-analysis on RSA migration of TKR are in line with both the survival analyses results from joint registries of these TKRs as well as revision rates results from meta-analyses, thus providing further proof for the association between early migration and late revision for loosening. The pooled migration patterns can be used both as benchmarks and for defining migration thresholds for future evaluation of new TKR.

  8. EVALUATION OF MIGRATION INTENTIONS OF THE YOUTH IN REGION (BY THE EXAMPLE OF REPUBLIC OF MORDOVIA

    Directory of Open Access Journals (Sweden)

    Andrey Anatolievich Sychev

    2016-02-01

    Full Text Available The article assesses the migration intentions of young people living in the Republic of Mordovia. The attention is focused on the migration intentions and moods as elements of the migratory behavior which act as an incentive to migrate. The authors analyze the results of the survey of young people and the structured interview and propose the measures aimed at reducing the outbound migration level in the region.In order to study the migration attitudes of the population in 2015 the survey of young people was carried out (quota type of sample, the selection was carried out by sex, age from 18 to 35, area of residence, 383 people were interviewed, with a 5% error supplemented with structured interview (9 persons interviewed, the selection of informants was based on the principle of intensive sampling.The results show that people in the Republic of Mordovia show clear migration intentions, and about half of them are focused on migration in the nearest future. If these intentions are realized, the region will face the increase of the rate of outflow of young working-age population. This phenomenon can entail a number of negative consequences, including shortages on the labor-markets, decline in the birth rate, population aging and others.Based on the results of the study recommendations are made to address the problems of migration in the region.

  9. The Relationship Between Post-Migration Stress and Psychological Disorders in Refugees and Asylum Seekers.

    Science.gov (United States)

    Li, Susan S Y; Liddell, Belinda J; Nickerson, Angela

    2016-09-01

    Refugees demonstrate high rates of post-traumatic stress disorder (PTSD) and other psychological disorders. The recent increase in forcible displacement internationally necessitates the understanding of factors associated with refugee mental health. While pre-migration trauma is recognized as a key predictor of mental health outcomes in refugees and asylum seekers, research has increasingly focused on the psychological effects of post-migration stressors in the settlement environment. This article reviews the research evidence linking post-migration factors and mental health outcomes in refugees and asylum seekers. Findings indicate that socioeconomic, social, and interpersonal factors, as well as factors relating to the asylum process and immigration policy affect the psychological functioning of refugees. Limitations of the existing literature and future directions for research are discussed, along with implications for treatment and policy.

  10. Effects of temperature, temperature gradients, stress, and irradiation on migration of brine inclusions in a salt repository

    International Nuclear Information System (INIS)

    Jenks, G.H.

    1979-07-01

    Available experimental and theoretical information on brine migration in bedded salt are reviewed and analyzed. The effects of temperature, thermal gradients, stress, irradiation, and pressure in a salt repository are among the factors considered. The theoretical and experimental (with KCl) results of Anthony and Cline were used to correlate and explain the available data for rates of brine migration at temperatures up to 250 0 C in naturally occurring crystals of bedded salt from Lyons and Hutchinson, Kansas. Considerations of the effects of stressing crystals of bedded salt on the migratin properties of brine inclusions within the crystals led to the conclusion that the most probable effects are a small fractional increase in the solubility of the salt within the liquid and a concomitant and equal fractional increase in the rate of the thermal gradient-induced migration of the brine. The greatest uncertainty relative to the prediction of rates of migration of brine into a waste emplacement cavity in bedded salt is associated with questions concerning the effects of the grain boundaries (within the aggregates of single crystals which comprise a bedded salt deposit) on brine migration through the deposit. The results of some of the estimates of rates and total amounts of brine inflow to HLW and SURF waste packages emplaced in bedded salt were included to illustrate the inflow volumes which might occur in a repository. The results of the brine inflow estimates for 10-year-old HLW emplaced at 150 kW/acre indicated inflow rates starting at 0.7 liter/year and totaling 12 liters at 30 years after emplacement. The results of the estimates for 10-year-old PWR SURF emplaced at 60 kW/acre indicated a constant inflow of 0.035 liter/year for the first 35 years after emplacement

  11. Labor migration in Asia.

    Science.gov (United States)

    Martin, P L

    1991-01-01

    "A recent conference sponsored by the United Nations Center for Regional Development (UNCRD) in Nagoya, Japan examined the growing importance of labor migration for four major Asian labor importers (Japan, Hong Kong, Malaysia, and Singapore) and five major labor exporters (Bangladesh, Korea, Pakistan, Philippines, and Thailand).... The conference concluded that international labor migration would increase within Asia because the tight labor markets and rising wages which have stimulated Japanese investment in other Asian nations, for example, have not been sufficient to eliminate migration push and pull forces...." excerpt

  12. Migrating mule deer: effects of anthropogenically altered landscapes.

    Directory of Open Access Journals (Sweden)

    Patrick E Lendrum

    Full Text Available Migration is an adaptive strategy that enables animals to enhance resource availability and reduce risk of predation at a broad geographic scale. Ungulate migrations generally occur along traditional routes, many of which have been disrupted by anthropogenic disturbances. Spring migration in ungulates is of particular importance for conservation planning, because it is closely coupled with timing of parturition. The degree to which oil and gas development affects migratory patterns, and whether ungulate migration is sufficiently plastic to compensate for such changes, warrants additional study to better understand this critical conservation issue.We studied timing and synchrony of departure from winter range and arrival to summer range of female mule deer (Odocoileus hemionus in northwestern Colorado, USA, which has one of the largest natural-gas reserves currently under development in North America. We hypothesized that in addition to local weather, plant phenology, and individual life-history characteristics, patterns of spring migration would be modified by disturbances associated with natural-gas extraction. We captured 205 adult female mule deer, equipped them with GPS collars, and observed patterns of spring migration during 2008-2010.Timing of spring migration was related to winter weather (particularly snow depth and access to emerging vegetation, which varied among years, but was highly synchronous across study areas within years. Additionally, timing of migration was influenced by the collective effects of anthropogenic disturbance, rate of travel, distance traveled, and body condition of adult females. Rates of travel were more rapid over shorter migration distances in areas of high natural-gas development resulting in the delayed departure, but early arrival for females migrating in areas with high development compared with less-developed areas. Such shifts in behavior could have consequences for timing of arrival on birthing areas

  13. Collective cell migration during inflammatory response

    Science.gov (United States)

    Wu, Di; Stroka, Kimberly; Aranda-Espinoza, Helim

    2012-02-01

    Wound scratch healing assays of endothelial cell monolayers is a simple model to study collective cell migration as a function of biological signals. A signal of particular interest is the immune response, which after initial wounding in vivo causes the release of various inflammatory factors such as tumor necrosis alpha (TNF-α). TNF-α is an innate inflammatory cytokine that can induce cell growth, cell necrosis, and change cell morphology. We studied the effects of TNF-α on collective cell migration using the wound healing assays and measured several migration metrics, such as rate of scratch closure, velocities of leading edge and bulk cells, closure index, and velocity correlation functions between migrating cells. We observed that TNF-α alters all migratory metrics as a function of the size of the scratch and TNF-α content. The changes observed in migration correlate with actin reorganization upon TNF-α exposure.

  14. Individualisation of Migration from the East? Comparison of Different Socio-Demographic Groups and their Migration Intentions

    Directory of Open Access Journals (Sweden)

    Maarja Saar

    2016-12-01

    Full Text Available Recent studies on Eastern European migration argue that moving for self-development reasons is becoming increasingly common among this group. Furthermore, it is suggested that migration from the East is becoming individualised and less dependent on social surroundings. Nevertheless, most such results rely on interviews conducted among certain social groups, such as the young and highly skilled. Hence, the comparison between different social groups and their motivations is rarely provided and, therefore, the claims about increased individualisation might be premature. This article uses the Estonian Household Module Survey, including responses from 620 Estonians intending to migrate, to evaluate if migration flows are indeed becoming more individualised and less dependent on social surroundings. Using cluster analysis, three different groups — self-development, economic and life quality migrants — are formed, which are then tested using regression analysis to check for the influence of socio-demographic variables. The article concludes that socio-demographic variables such as gender, age, ethnicity, family status and socio-economic status are still relevant for migration intentions. Indeed, a new group of Eastern European migrants, mainly oriented towards self-development, is emerging; however, it is small and consists mostly of young, Estonian-speaking females. The results complicate the notions of free mobility and liquid migration from Eastern Europe and illustrate that there is a need to pay attention to the increasing group differences in these societies

  15. Migration rates of volatile organic compounds in an unconsolidated sand and gravel aquifer system

    International Nuclear Information System (INIS)

    Naidu, J.R.; Paquette, D.E.; Porcelli, D.R.

    1993-01-01

    The movement of volatile organic compounds (VOCs) in an aquifer is dictated by its solubility, attenuation characteristics, recharge volume, and ground-water movement (velocity and direction). At Brookhaven National Laboratory, past handling and disposal practices at the Hazardous Waste Management Facility and current landfill have resulted in the release of VOCs and the radioisotope tritium to the underlying upper glacial aquifer which characterized by unconsolidated sands and gravel. The rate of VOC migration from these source areas was examined using the following parameters: (1) distribution of VOCs and tritium; (2) tritium/helium ratios, which provide an estimate of the age of the water, and hence the rate of ground-water movement; (3) ground-water flow velocities within the upper glacial aquifer utilizing conductivity, porosity, and gradient data. Preliminary results indicate that whereas the comparison of the calculated ground-water flow gradient to tritium/helium age determinations are fairly consistent, application to VOC movement is inconclusive, and will require additional monitoring which would also focus on the vertical component as well

  16. 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.

  17. 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.

  18. Vulnerable to HIV / AIDS. Migration.

    Science.gov (United States)

    Fernandez, I

    1998-01-01

    This special report discusses the impact of globalization, patterns of migration in Southeast Asia, gender issues in migration, the links between migration and HIV/AIDS, and spatial mobility and social networks. Migrants are particularly marginalized in countries that blame migrants for transmission of infectious and communicable diseases and other social ills. Effective control of HIV/AIDS among migrant and native populations requires a multisectoral approach. Programs should critically review the privatization of health care services and challenge economic models that polarize the rich and the poor, men and women, North and South, and migrant and native. Programs should recognize the equality between locals and migrants in receipt of health services. Countermeasures should have input from migrants in order to reduce the conditions that increase vulnerability to HIV/AIDS. Gender-oriented research is needed to understand women's role in migration. Rapid assessment has obscured the human dimension of migrants' vulnerability to HIV. Condom promotion is not enough. Migration is a major consequence of globalization, which holds the promise, real or imagined, of prosperity for all. Mass migration can be fueled by explosive regional developments. In Southeast Asia, migration has been part of the process of economic development. The potential to emigrate increases with greater per capita income. "Tiger" economies have been labor importers. Safe sex is not practiced in many Asian countries because risk is not taken seriously. Migrants tend to be used as economic tools, without consideration of social adjustment and sex behavior among singles.

  19. Suture fixation of migrated septal occluder device to prevent further migration: a simple surgical technique

    Directory of Open Access Journals (Sweden)

    Mohite Prashant N

    2013-01-01

    Full Text Available Abstract As the use of percutaneous intervention is increasing for the closure of the atrial septal defect, the procedure related complications are also on rise, migration of the device being most common. The migrated devices with failed percutaneous retrieval must be removed surgically under cardiopulmonary bypass. During establishment of cardiopulmonary bypass, the handling of heart may cause further migration of the device into other chambers of heart which leads to difficulty in finding and retrieval of the device. The authors propose a simple and unique technique to prevent further migration of the septal occluder device.

  20. Increased asthma and adipose tissue inflammatory gene expression with obesity and Inuit migration to a western country.

    Science.gov (United States)

    Backer, Vibeke; Baines, Katherine J; Powell, Heather; Porsbjerg, Celeste; Gibson, Peter G

    2016-02-01

    An overlap between obesity and asthma exists, and inflammatory cells in adipose tissue could drive the development of asthma. Comparison of adipose tissue gene expression among Inuit living in Greenland to those in Denmark provides an opportunity to assess how changes in adipose tissue inflammation can be modified by migration and diet. To examine mast cell and inflammatory markers in adipose tissue and the association with asthma. Two Inuit populations were recruited, one living in Greenland and another in Denmark. All underwent adipose subcutaneous biopsy, followed by clinical assessment of asthma, and measurement of AHR. Adipose tissue biopsies were homogenised, RNA extracted, and PCR was performed to determine the relative gene expression of mast cell (tryptase, chymase, CPA3) and inflammatory markers (IL-6, IL-1β, and CD163). Of the 1059 Greenlandic Inuit participants, 556 were living in Greenland and 6.4% had asthma. Asthma was increased in Denmark (9%) compared to Greenland (3.6%, p Inuit (p Inuit, adipose tissue inflammation is also increased in those who migrate to Denmark, possibly as a result of dietary changes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Mechanics of arterial subfailure with increasing loading rate.

    Science.gov (United States)

    Stemper, Brian D; Yoganandan, Narayan; Pintar, Frank A

    2007-01-01

    Arterial subfailure leads to delayed symptomatology and high morbidity and mortality rates, particularly for the thoracic aorta and carotid arteries. Although arterial injuries occur during high-velocity automotive collisions, previous studies of arterial subfailure focused on quasi-static loading. This investigation subjected aortic segments to increasing loading rates to quantify effects on elastic, subfailure, and ultimate vessel mechanics. Sixty-two specimens were axially distracted, and 92% demonstrated subfailure before ultimate failure. With increasing loading rate, stress at initial subfailure and ultimate failure significantly increased, and strain at initial subfailure and ultimate failure significantly decreased. Present results indicate increased susceptibility for arterial subfailure and/or dissection under higher-rate extension. According to the present results, automotive occupants are at greater risk of arterial injury under higher velocity impacts due to greater body segment motions in addition to decreased strain tolerance to subfailure and catastrophic failure.

  2. Vertical migration of 85Sr, 137Cs and 131I in various arable and undisturbed soils

    International Nuclear Information System (INIS)

    Palagyi, S.; Palagyiova, J.

    2002-01-01

    Vertical migration of 85 Sr, 137 Cs and 131 I in some arable and undisturbed single-contaminated soils was studied by gamma-spectrometry measurements in lysimetric laboratory conditions applying irrigation of the soil profiles with wet atmospheric precipitation for about one year (except radioiodine). A new simple exponential compartment (box) model was derived, allowing us to calculate the migration rate constants and migration rates in the individual soil layers (vertical sections) as well as the total vertical migration rate constants and total vertical migration rates of radionuclides in the bulk soil horizon. The data from the time dependence of the depth activity distribution (radionuclide concentration along the vertical soil profile) were used to test the model. The migration rate constants and migration rates were found to be affected by the contaminating radionuclides as well as by the site, type and depth of the soil. The relaxation times of the radionuclides in the soil horizons were calculated. The effects on the rate parameters of the permanent grass cover and the zeolite applied onto the arable soil surfaces were also investigated

  3. [Migrations in Latin American countries. Characteristics of the pediatric population].

    Science.gov (United States)

    Vásquez-De Kartzow, Rodrigo; Castillo-Durán, Carlos; Lera M, Lydia

    2015-01-01

    Migration is a growing phenomenon among Latin American countries (LAC) as well as others; however, scarce information is available studying its impact on paediatric groups and its association with socioeconomic variables. To study the association among socioeconomic variables and the immigration rate of paediatric population in LAC. Official rates of migration of LAC were obtained from: International Organization for Migration, Pan American Health Organization, and United Nations Development Programme. Demographic and socioeconomic information was also obtained for: gross domestic product (GDP), human development index (HDI), Gini coefficient of inequality (GC), alphabetization rate for adults (AA), net migration rate (NMR), and immigration of childrenChile and Argentina. No association among NMR and GDP, HDI, GC, AA was found. A correlation of IM15 was found with: GC (r=0.668, P=.01), with GDP (r=-0.720; P=.01), AA (r=-0.755; P=.01) and with HDI (r=-0.799; P=.01). Rate of IM15 was lower in LA countries with advanced/medium development (GDP>median) vs those with low development (Fisher, P<.0001). There is a direct inverse association between GDP per capita, HDI, AA and GC and the proportion of each country IN15. We did not observe an association between NMR and HDI, AA, and GC. The health impact of these migrations should be analysed. Copyright © 2015. Publicado por Elsevier España, S.L.U.

  4. Domestic and International Climate Migration from Rural Mexico

    Science.gov (United States)

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

    2016-01-01

    Evidence is increasing that climate change and variability may influence human migration patterns. However, there is less agreement regarding the type of migration streams most strongly impacted. This study tests whether climate change more strongly impacted international compared to domestic migration from rural Mexico during 1986-99. We employ eight temperature and precipitation-based climate change indices linked to detailed migration histories obtained from the Mexican Migration Project. Results from multilevel discrete-time event-history models challenge the assumption that climate-related migration will be predominantly short distance and domestic, but instead show that climate change more strongly impacted international moves from rural Mexico. The stronger climate impact on international migration may be explained by the self-insurance function of international migration, the presence of strong migrant networks, and climate-related changes in wage difference. While a warming in temperature increased international outmigration, higher levels of precipitation declined the odds of an international move. PMID:28439146

  5. Domestic and International Climate Migration from Rural Mexico.

    Science.gov (United States)

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

    2016-12-01

    Evidence is increasing that climate change and variability may influence human migration patterns. However, there is less agreement regarding the type of migration streams most strongly impacted. This study tests whether climate change more strongly impacted international compared to domestic migration from rural Mexico during 1986-99. We employ eight temperature and precipitation-based climate change indices linked to detailed migration histories obtained from the Mexican Migration Project. Results from multilevel discrete-time event-history models challenge the assumption that climate-related migration will be predominantly short distance and domestic, but instead show that climate change more strongly impacted international moves from rural Mexico. The stronger climate impact on international migration may be explained by the self-insurance function of international migration, the presence of strong migrant networks, and climate-related changes in wage difference. While a warming in temperature increased international outmigration, higher levels of precipitation declined the odds of an international move.

  6. Thermal Stress Limit Rafting Migration of Seahorses: Prediction Based on Physiological and Behavioral Responses to Thermal Stress

    Science.gov (United States)

    Qin, G.; Li, C.; Lin, Q.

    2017-12-01

    Marine fish species escape from harmful environment by migration. Seahorses, with upright posture and low mobility, could migrate from unfavorable environment by rafting with their prehensile tail. The present study was designed to examine the tolerance of lined seahorse Hippocampus erectus to thermal stress and evaluate the effects of temperature on seahorse migration. The results figured that seahorses' tolerance to thermal stress was time dependent. Acute thermal stress (30°C) increased breathing rate and HSP genes expression significantly, but didn't affect seahorse feeding behavior. Chronic thermal treatment lead to persistent high expression of HSP genes, higher breathing rate, and decreasing feeding, and final higher mortality, suggesting that seahorse cannot adapt to thermal stress by acclimation. No significant negative effects were found in seahorse reproduction in response to chronic thermal stress. Given that seahorses make much slower migration by rafting on sea surface compared to other fishes, we suggest that thermal stress might limit seahorse migration range. and the influence might be magnified by global warming in future.

  7. A STUDY ON THE INTERNAL MIGRATION FLOWS IN TURKEY: LOWRY HYPOTHESIS

    Directory of Open Access Journals (Sweden)

    FERHAT TOPBAŞ

    2013-06-01

    Full Text Available The purpose of this study is to re-examine Lowry hypothesis that were examined for Turkey in period of 1965–1980 by Gedik (1992 and period of 1985–1990 by Yamak and Küçükkale (2001 by using The Census of Population 1975, 1980, 1985, 1990 and 2000 in Turkey. For this reason, the relationships between in-migration and out-migration and net migration have investigated with population size, net migration rate and per capita income factors. Analysis that involve in all provinces called general model is not considered in social, economic and urban development factors. In addition, estimated restriction models that are considered urban development are involved population, net migration rate and per capita income factors. In conclusion we have exposed comparatively relationship between internal migration flows and urban development frame of estimated models.

  8. 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...

  9. 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

  10. 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)

  11. Do American dippers obtain a survival benefit from altitudinal migration?

    Science.gov (United States)

    Green, David J; Whitehorne, Ivy B J; Middleton, Holly A; Morrissey, Christy A

    2015-01-01

    Studies of partial migrants provide an opportunity to assess the cost and benefits of migration. Previous work has demonstrated that sedentary American dippers (residents) have higher annual productivity than altitudinal migrants that move to higher elevations to breed. Here we use a ten-year (30 period) mark-recapture dataset to evaluate whether migrants offset their lower productivity with higher survival during the migration-breeding period when they occupy different habitat, or early and late-winter periods when they coexist with residents. Mark-recapture models provide no evidence that apparent monthly survival of migrants is higher than that of residents at any time of the year. The best-supported model suggests that monthly survival is higher in the migration-breeding period than winter periods. Another well-supported model suggested that residency conferred a survival benefit, and annual apparent survival (calculated from model weighted monthly apparent survival estimates using the Delta method) of residents (0.511 ± 0.038SE) was slightly higher than that of migrants (0.487 ± 0.032). Winter survival of American dippers was influenced by environmental conditions; monthly apparent survival increased as maximum daily flow rates increased and declined as winter temperatures became colder. However, we found no evidence that environmental conditions altered differences in winter survival of residents and migrants. Since migratory American dippers have lower productivity and slightly lower survival than residents our data suggests that partial migration is likely an outcome of competition for limited nest sites at low elevations, with less competitive individuals being forced to migrate to higher elevations in order to breed.

  12. 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

  13. Mental health of newly arrived Burmese refugees in Australia: contributions of pre-migration and post-migration experience.

    Science.gov (United States)

    Schweitzer, Robert D; Brough, Mark; Vromans, Lyn; Asic-Kobe, Mary

    2011-04-01

    This study documents the mental health status of people from Burmese refugee backgrounds recently arrived in Australia, then examines the contributions of gender, pre-migration and post-migration factors in predicting mental health. Structured interviews, including a demographic questionnaire, the Harvard Trauma Questionnaire, the Post-migration Living Difficulties Checklist and Hopkins Symptom Checklist assessed pre-migration trauma, post-migration living difficulties, depression, anxiety, somatization and traumatization symptoms in a sample of 70 adults across five Burmese ethnic groups. Substantial proportions of participants reported psychological distress in symptomatic ranges including: post-traumatic stress disorder (9%), anxiety (20%) and depression (36%), as well as significant symptoms of somatization (37%). Participants reported multiple and severe pre-migration traumas. Post-migration living difficulties of greatest concern included communication problems and worry about family not in Australia. Gender did not predict mental health. Level of exposure to traumatic events and post-migration living difficulties each made unique and relatively equal contributions to traumatization symptoms. Post-migration living difficulties made unique contributions to depression, anxiety and somatization symptoms. While exposure to traumatic events impacted on participants' mental well-being, post-migration living difficulties had greater salience in predicting mental health outcomes of people from Burmese refugee backgrounds. Reported rates of post-traumatic stress disorder symptoms were consistent with a large review of adults across seven western countries. High levels of somatization point to a nuanced expression of distress. Findings have implications for service provision in terms of implementing appropriate interventions to effectively meet the needs of this newly arrived group in Australia.

  14. QUALIFIED VERSION OF MIGRATION: BRAIN DRAIN

    OpenAIRE

    Ayhan GENCLER

    2009-01-01

    Though globalization suggests an international exchange of people besides goods and capital, developed countries often tended to put forward some restrictions on the migration of workers from developed countries. However, there has been an increase in skilled international migration especially during the last two decades. Skilled international migration or brain drain points out the emigration of educated and highly skilled workers. It seems tha...

  15. Industrial Based Migration in India. A Case Study of Dumdum "Dunlop Industrial Zone"

    Science.gov (United States)

    Das, Biplab; Bandyopadhyay, Aditya; Sen, Jayashree

    2012-10-01

    Migration is a very important part in our present society. Basically Millions of people moved during the industrial revolution. Some simply moved from a village to a town in the hope of finding work whilst others moved from one country to another in search of a better way of life. The main reason for moving home during the 19th century was to find work. On one hand this involved migration from the countryside to the growing industrial cities, on the other it involved rates of migration, emigration, and the social changes that were drastically affecting factors such as marriage,birth and death rates. These social changes taking place as a result of capitalism had far ranging affects, such as lowering the average age of marriage and increasing the size of the average family.Migration was not just people moving out of the country, it also invloved a lot of people moving into Britain. In the 1840's Ireland suffered a terrible famine. Faced with a massive cost of feeding the starving population many local landowners paid for labourers to emigrate.There was a shift away from agriculturally based rural dwelling towards urban habitation to meet the mass demand for labour that new industry required. There became great regional differences in population levels and in the structure of their demography. This was due to rates of migration, emigration, and the social changes that were drastically affecting factors such as marriage, birth and death rates. These social changes taking place as a result of capitalism had far ranging affects, such as lowering the average age of marriage and increasing the size of the average family. There is n serious disagreement as to the extent of the population changes that occurred but one key question that always arouses debate is that of whether an expanding population resulted in economic growth or vice versa, i.e. was industrialization a catalyst for population growth? A clear answer is difficult to decipher as the two variables are so

  16. The influence of rural-urban migration on migrant's fertility behavior in Cameroon.

    Science.gov (United States)

    Lee, B S

    1992-01-01

    Preliminary analysis of Cameroon fertility data suggests that rural stayers do not have a significantly higher fertility than rural-urban migrants in contrast to hypotheses suggested in the literature. Bongaarts and Caldwell both suggest that modernization plays a role in African fertility and migration patterns by increasing exposure to childbearing. Supply constraints are changed by higher levels of education, short duration of postpartum abstinence, less prevalence of polygamy, and more stable marriages. The influence of relatives may be weaker and the fear of losing a husband greater, which influence earlier returns to sexual relations. Because the levels of fertility of stayers and movers may be equal does not suggest that movers do not adapt fertility to urban norms. Analysis was conducted with d ata from the 1978 Cameroon World Fertility Survey on 8219 women aged 15-54 years for rural nonmigrants, rural-rural migrants, and rural-urban migrants. Rural-urban migrants were found to be better educated, have fewer cases of infertility, and have more stable first marriages. Descriptive statistics are provided for migrants and nonmigrants. Cross classification analysis shows that fertility is not lower for women with higher education, even when migration status is controlled for. Multivariate regression results in an autoregressive model in a first difference form indicated that the fertility rate of rural-urban migrant women was significantly higher than that of rural staryers during the period of 5-9 years after migration. The urban effect acts to reduce migrants' fertility by about .13 births. Comparisons are made with Mexican and Korean migration behavior, which reflect decreased fertility after migration of 1.5 births and 2.6 births, respectively. The suggestion is that the fertility-increasing effect of supply conditions in Cameroon is significantly offset by the fertility-depressing adaptation effect of migration to urban areas. It is expected that

  17. Increasing preferred step rate during running reduces plantar pressures.

    Science.gov (United States)

    Gerrard, James M; Bonanno, Daniel R

    2018-01-01

    Increasing preferred step rate during running is a commonly used strategy in the management of running-related injuries. This study investigated the effect of different step rates on plantar pressures during running. Thirty-two healthy runners ran at a comfortable speed on a treadmill at five step rates (preferred, ±5%, and ±10%). For each step rate, plantar pressure data were collected using the pedar-X in-shoe system. Compared to running with a preferred step rate, a 10% increase in step rate significantly reduced peak pressure (144.5±46.5 vs 129.3±51 kPa; P=.033) and maximum force (382.3±157.6 vs 334.0±159.8 N; P=.021) at the rearfoot, and reduced maximum force (426.4±130.4 vs 400.0±116.6 N; P=.001) at the midfoot. In contrast, a 10% decrease in step rate significantly increased peak pressure (144.5±46.5 vs 161.5±49.3 kPa; P=.011) and maximum force (382.3±157.6 vs 425.4±155.3 N; P=.032) at the rearfoot. Changing step rate by 5% provided no effect on plantar pressures, and no differences in plantar pressures were observed at the medial forefoot, lateral forefoot or hallux between the step rates. This study's findings indicate that increasing preferred step rate by 10% during running will reduce plantar pressures at the rearfoot and midfoot, while decreasing step rate by 10% will increase plantar pressures at the rearfoot. However, changing preferred step rate by 5% will provide no effect on plantar pressures, and forefoot pressures are unaffected by changes in step rate. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Migration Flow and Its Impact on Tuberculosis Notification in Portugal.

    Science.gov (United States)

    Dias, Ana; Gaio, Rita; Sousa, Pedro; Gomes, Marta; Oliveira, Olena; Duarte, Raquel

    2018-01-01

    Tuberculosis notification in Portugal has decreased in the last few years. As a consequence of the economic crisis, emigration has increased and immigration has decreased. Immigrants are a risk group for tuberculosis. Most emigrants are 20-44 years old and belong to the age group most affected by tuberculosis. To describe the decrease in tuberculosis notification in Portugal over the last years from a demographical point of view. Mathematical analysis was performed to quantify the effect of the migration movements (separately and simultaneously) on tuberculosis notification in Portugal from 2008 to 2014. We calculated the estimated tuberculosis notification for each year during the period of study: 1) fixing immigration rate and tuberculosis rate in immigrants at 2008 values; 2) fixing emigration rate and tuberculosis rate in emigrants at 2008 values; 3) fixing both phenomenons at 2008 values. The differences between the observed and the estimated numbers were small (≤0.5 cases/100000 inhabitants). Impact of the migration movements on tuberculosis notification rate does not seem to be significant when analyzed for each phenomenon individually and simultaneously, by our model. This might mean that we have to concentrate our efforts in other risk factors for tuberculosis. Copyright © 2017 SEPAR. Publicado por Elsevier España, S.L.U. All rights reserved.

  19. Vertical migration of 85Sr, 137Cs and 131I in various arable and undisturbed soils

    International Nuclear Information System (INIS)

    Palagyi, S.; Palagyiova, J.

    2003-01-01

    The vertical migration of 85 Sr, 137 Cs and 131 I in some arable and undisturbed single-contaminated soils was studied by gamma-spectrometry measurements under lysimetric laboratory conditions during irrigation of the soil profiles with wet atmospheric precipitation for about one year, except 131 I. A new simple exponential compartment (box) model was derived, which makes it possible to calculate the migration rate constants and migration rates in the individual soil layers (vertical sections) as well as the total vertical migration rate constants and total vertical migration rates of radionuclides in the bulk soil horizon. The relaxation times of radionuclides in respective soil horizons can also be evaluated. (author)

  20. Intake rates, stochasticity, or onset of spring – what aspects of food availability affect spring migration patterns in Pink-footed Geese Anser brachyrhynchus?

    NARCIS (Netherlands)

    Bauer, S.; Madsen, J.; Klaassen, M.R.J.

    2006-01-01

    Long-distance bird migration consists of several flight episodes interrupted by a series of resting and refuelling periods on stopover sites. We assessed the role of food availability as the determinant of staging decisions focusing on the following three aspects of food availability: intake rates,

  1. Evaluation of gas migration characteristics of compacted and saturated Ca-bentonite mixture

    International Nuclear Information System (INIS)

    Tanaka, Yukihisa; Hironaga, Michihiko

    2014-01-01

    In the current concept of near-surface pit disposal for low level radioactive waste, compacted bentonite mixture will be used as an engineered barrier mainly for inhibiting migration of radioactive nuclides. Hydrogen gas can be generated inside the engineered barrier mainly by the chemical interaction between aluminum and the alkaline component of cement, or water. If the gas generation rate exceeds the diffusion rate of gas molecules inside of the compacted bentonite mixture, gas will accumulate in the void space inside of the compacted bentonite mixture until its pressure becomes large enough for it to enter the compacted bentonite mixture as a discrete gaseous phase. It is expected to be not easy for gas to entering into the compacted bentonite mixture as a discrete gaseous phase because the pore of the compacted bentonite mixture is so minute. Therefore in this study, the gas migration characteristics and the effect of gas migration on the hydraulic conductivity of the compacted Ca-bentonite mixture are investigated by the gas migration tests. The effect of stress state on the migration characteristics is also investigated by the gas migration tests and by parametric study using the model of two phase flow through deformable porous media, which was originally developed by CRIEPI. Results of this study imply that : (1) Large gas breakthrough pressure, which is defined as a rapid increase of amount of discharged gas, is affected by initial stress conditions as well as Ca-bentonite content of the mixture. (2) Hydraulic conductivity measured after the large gas breakthrough is substantially the same that measured before the gas migration test. (3) Axial stress change and volume change of the specimen during the gas migration test can be reproduced by the numerical simulation using the model of two-phase flow through deformable porous media, which was originally developed by CRIEPI. (4) Gas migration of a small scale model is numerically simulated to investigate the

  2. Electrochemical migration technique to accelerate ageing of cementitious materials

    Directory of Open Access Journals (Sweden)

    Abbas Z.

    2013-07-01

    Full Text Available Durability assessment of concrete structures for constructions in nuclear waste repositories requires long term service life predictions. As deposition of low and intermediate level radioactive waste (LILW takes up to 100 000 years, it is necessary to analyze the service life of cementitious materials in this time perspective. Using acceleration methods producing aged specimens would decrease the need of extrapolating short term data sets. Laboratory methods are therefore, needed for accelerating the ageing process without making any influencing distortion in the properties of the materials. This paper presents an electro-chemical migration method to increase the rate of calcium leaching from cementitious specimens. This method is developed based on the fact that major long term deterioration process of hardened cement paste in concrete structures for deposition of LILW is due to slow diffusion of calcium ions. In this method the cementitious specimen is placed in an electrochemical cell as a porous path way through which ions can migrate at a rate far higher than diffusion process. The electrical field is applied to the cell in a way to accelerate the ion migration without making destructions in the specimen’s micro and macroscopic properties. The anolyte and catholyte solutions are designed favoring dissolution of calcium hydroxide and compensating for the leached calcium ions with another ion like lithium.

  3. Electrochemical migration technique to accelerate ageing of cementitious materials

    Science.gov (United States)

    Babaahmadi, A.; Tang, L.; Abbas, Z.

    2013-07-01

    Durability assessment of concrete structures for constructions in nuclear waste repositories requires long term service life predictions. As deposition of low and intermediate level radioactive waste (LILW) takes up to 100 000 years, it is necessary to analyze the service life of cementitious materials in this time perspective. Using acceleration methods producing aged specimens would decrease the need of extrapolating short term data sets. Laboratory methods are therefore, needed for accelerating the ageing process without making any influencing distortion in the properties of the materials. This paper presents an electro-chemical migration method to increase the rate of calcium leaching from cementitious specimens. This method is developed based on the fact that major long term deterioration process of hardened cement paste in concrete structures for deposition of LILW is due to slow diffusion of calcium ions. In this method the cementitious specimen is placed in an electrochemical cell as a porous path way through which ions can migrate at a rate far higher than diffusion process. The electrical field is applied to the cell in a way to accelerate the ion migration without making destructions in the specimen's micro and macroscopic properties. The anolyte and catholyte solutions are designed favoring dissolution of calcium hydroxide and compensating for the leached calcium ions with another ion like lithium.

  4. QUALIFIED VERSION OF MIGRATION: BRAIN DRAIN

    OpenAIRE

    Gencler, Ayhan

    2009-01-01

    Though globalization suggests an international exchange of people besides goods and capital, developed countries often tended to put forward some restrictions on the migration of workers from developed countries. However, there has been an increase in skilled international migration especially during the last two decades. Skilled international migration or brain drain points out the emigration of educated and highly skilled workers. It seems that, in general, developing or underdeveloped...

  5. 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.

  6. Business cycles, migration and health.

    Science.gov (United States)

    Halliday, Timothy J

    2007-04-01

    We investigate the proposition that illness poses as an obstacle to one's ability to use migration to hedge the business cycle. We employ data on migration, regional unemployment rates and health status from 10 years (1984-1993) of the US Panel Study of Income Dynamics. Our results provide considerable for support this proposition. The evidence is the strongest for men, but we also find weaker evidence for married women. These results suggest that--ceterus paribus--aggregate health outcomes in an area should improve when the regional economy expands.

  7. Migration of radionuclides in fissured rock

    International Nuclear Information System (INIS)

    Neretnieks, I.

    1982-01-01

    Some computed results of radionuclide migration in fissured rock are presented. The computations are based on a model which describes flow as occurring in a multitude of independent fissures (stratified flow). This gives rise to strong dispersion of channeling. The radionuclide migration in the individual fissures is modelled by the advection equation on a parallel walled channel with porous walls. The nuclides may diffuse into the pores and sorb reversibly on the pore surfaces. The effluent rates of 23 important nuclides are presented as functions of distance and time for various of important parameters such as rock permeability, diffusion coefficients, release rates, time of first release, fissure spacing and fissure width distribution. (Author)

  8. MIGRATE: A FOSS WEB MAPPING APPLICATION FOR EDUCATING AND RAISING AWARENESS ABOUT MIGRATION FLOWS IN EUROPE

    Directory of Open Access Journals (Sweden)

    M. A. Brovelli

    2017-07-01

    Full Text Available Recent years have seen a noticeable growth in migration flows from Africa and Middle East to Southern Europe, thus generating a remarkable increase of attention on media and public opinion, sometimes resulting in stereotypes and prejudices. Funded by the European Commission – Joint Research Centre through the MYGEOSS program, MIGRation pATtterns in Europe (MIGRATE aims at educating the citizens about migration fluxes in Europe using a gamification approach based on a trivia game. MIGRATE is completely developed with Free and Open Source Software. On the server-side Django is used to define the models that handle all the required data and tables are created in a PostgreSQL database. Questions and answers are sent in JSON format to the client, while the geospatial layers in GeoJSON format are rendered on the map interface using OpenLayers 3. Bootstrap, HTML5 and CSS3 are used for responsive design, while the jQuery library is used to ease the JavaScript programming. All the data sources used within MIGRATE are available as full and open access with no restrictions for reuse, except for the obligation to mention the source of the input data. Exploited data sources include OpenStreetMap for geospatial information, and UNHCR, IOM, Eurostat and The Migrant’s Files project for non-geospatial information. Overall, data shows how the users’ perceptions change while playing and that players’ awareness of migration-related problems increases with the number of games played. The source code of MIGRATE and the collected data are available respectively under the EU Public License (EUPL and the CC BY 4.0 license.

  9. Multiscale Cues Drive Collective Cell Migration

    Science.gov (United States)

    Nam, Ki-Hwan; Kim, Peter; Wood, David K.; Kwon, Sunghoon; Provenzano, Paolo P.; Kim, Deok-Ho

    2016-07-01

    To investigate complex biophysical relationships driving directed cell migration, we developed a biomimetic platform that allows perturbation of microscale geometric constraints with concomitant nanoscale contact guidance architectures. This permits us to elucidate the influence, and parse out the relative contribution, of multiscale features, and define how these physical inputs are jointly processed with oncogenic signaling. We demonstrate that collective cell migration is profoundly enhanced by the addition of contract guidance cues when not otherwise constrained. However, while nanoscale cues promoted migration in all cases, microscale directed migration cues are dominant as the geometric constraint narrows, a behavior that is well explained by stochastic diffusion anisotropy modeling. Further, oncogene activation (i.e. mutant PIK3CA) resulted in profoundly increased migration where extracellular multiscale directed migration cues and intrinsic signaling synergistically conspire to greatly outperform normal cells or any extracellular guidance cues in isolation.

  10. The Last Adventure: Retirement Migration, Climate and "Amenities"

    Directory of Open Access Journals (Sweden)

    Saša Božić

    2001-12-01

    Full Text Available The rising number of European retirement migrants on the Mediterranean coasts, especially in the EU countries shows that the practical and scientific relevance of the new forms of migration in Europe is on the rise. "Retirement migration" evolved from a descriptive term to a candidate for a scientific or a research concept, at least if the use of the term IRM (international retirement migration is considered. However, it is necessary to solve several problems before this term can really become a coherent concept, useful for the research and explanation of the "new" migration phenomena. The author claims that the studies usually do not distinguish clearly between the migration of the elderly and retirement migration. The naming of the concept in this case mixes the characteristics of the migrants with the reasons for migration. The author shows that the usually mentioned reasons for retirement migration cannot be clearly formulated as factors which explain retirement migration. Further on, retirement as such is not a pull, push or staying put factor. Migration rates of retired, although rising, are still lower than the migration rates of the working age population and the Mediterranean coasts are also a destination for professionals who have the means to detach the job from the working place. Only a combination of conditions that enable migration and migration decisions, as well as a combination of motives and perceptions of reasons for migration, can partially "explain" retirement migration. One of the problems that has to be solved before retirement migration is affirmed as a concept is the treatment of the temporal and spatial dimension of the mobility of the retirement migrants. The author shows that a clear positioning of retirement migration on the temporal scale of mobility is hardly possible. Retirement migration is too wide and too complex a phenomenon to be easily localised in the temporal continuum. A similar problem emerges when the

  11. Spatial and temporal migration of a landfill leachate plume in alluvium

    Science.gov (United States)

    Masoner, Jason R.; Cozzarelli, Isabelle M.

    2015-01-01

    Leachate from unlined or leaky landfills can create groundwater contaminant plumes that last decades to centuries. Understanding the dynamics of leachate movement in space and time is essential for monitoring, planning and management, and assessment of risk to groundwater and surface-water resources. Over a 23.4-year period (1986–2010), the spatial extent of the Norman Landfill leachate plume increased at a rate of 7800 m2/year and expanded by 878 %, from an area of 20,800 m2 in 1986 to 203,400 m2 in 2010. A linear plume velocity of 40.2 m/year was calculated that compared favorably to a groundwater-seepage velocity of 55.2 m/year. Plume-scale hydraulic conductivity values representative of actual hydrogeological conditions in the alluvium ranged from 7.0 × 10−5 to 7.5 × 10−4 m/s, with a median of 2.0 × 10−4 m/s. Analyses of field-measured and calculated plume-scale hydraulic conductivity distributions indicate that the upper percentiles of field-measured values should be considered to assess rates of plume-scale migration, spreading, and biodegradation. A pattern of increasing Cl− concentrations during dry periods and decreasing Cl− concentrations during wet periods was observed in groundwater beneath the landfill. The opposite occurred in groundwater downgradient from the landfill; that is, Cl− concentrations in groundwater downgradient from the landfill decreased during dry periods and increased during wet periods. This pattern of changing Cl−concentrations in response to wet and dry periods indicates that the landfill retains or absorbs leachate during dry periods and produces lower concentrated leachate downgradient. During wet periods, the landfill receives more recharge which dilutes leachate in the landfill but increases leachate migration from the landfill and produces a more concentrated contaminant plume. This approach of quantifying plume expansion, migration, and concentration during variable hydrologic

  12. A lean and mean strategy: a data migration industrial study

    NARCIS (Netherlands)

    Razavian, M.; Lago, P.

    2014-01-01

    Many companies have legacy assets to be integrated or modernized. Like today's software developments, migration projects are faced with steadily increasing demands for efficiency: migration has to be carried out faster, better, and cheaper. At the same time, migration complexity increases, and

  13. Amplification or suppression: Social networks and the climate change-migration association in rural Mexico.

    Science.gov (United States)

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

    2015-11-01

    Increasing rates of climate migration may be of economic and national concern to sending and destination countries. It has been argued that social networks - the ties connecting an origin and destination - may operate as "migration corridors" with the potential to strongly facilitate climate change-related migration. This study investigates whether social networks at the household and community levels amplify or suppress the impact of climate change on international migration from rural Mexico. A novel set of 15 climate change indices was generated based on daily temperature and precipitation data for 214 weather stations across Mexico. Employing geostatistical interpolation techniques, the climate change values were linked to 68 rural municipalities for which sociodemographic data and detailed migration histories were available from the Mexican Migration Project. Multi-level discrete-time event-history models were used to investigate the effect of climate change on international migration between 1986 and 1999. At the household level, the effect of social networks was approximated by comparing the first to the last move, assuming that through the first move a household establishes internal social capital. At the community level, the impact of social capital was explored through interactions with a measure of the proportion of adults with migration experience. The results show that rather than amplifying , social capital may suppress the sensitivity of migration to climate triggers, suggesting that social networks could facilitate climate change adaptation in place.

  14. Demographic situation and population migration problems

    International Nuclear Information System (INIS)

    1993-01-01

    Problem of the Chernobyl accident effect on the population migration in controlled areas of the Ukraine, Belarus and in Russian Federation. Comparison of the data on migration for 1990 and for 1995 has shown considerable growth of the intensity of efflux of rural population at most Ukrainian areas affected due to the Chernobyl accident. Negative migration growth in urban settlements of these regions is marked. Decrease in rural resident migration is observed. Migrant current in Russia is twice increased. Main regions of North-West, Central, North-Caucasus ones in Russia and Donetsk-Dnieper river in the Ukraine. 6 tabs

  15. [Women in labor and migration. The female labor market between 1950 and 1990 and migration of women to Santiago, Chile].

    Science.gov (United States)

    Szasz, I

    1994-06-01

    Changes in the volume of female migration to Santiago and in the employment patterns of migrant women are analyzed in relationship to changes in the female labor market from 1950 onward, with special emphasis on the years 1970-90. Data sources include published works, the censuses of 1952 to 1982, a 1962 survey on in-migration to Santiago, employment surveys conducted by the University of Chile and the National Institute of Statistics, special tabulations for subsamples of the 1970 and 1982 censuses, and household employment survey information from the fourth quarter of 1993. In 1973 Chile embarked on a process of structural adjustments that affected social expenditures and employment, profoundly modifying urban labor markets. The Chilean economy is currently in a phase of consolidating its productive transformation, with positive results for economic growth and recuperation of employment, but with no reduction of poverty. The explanation of the growth in poverty should be sought in modifications in the conditions of employment of the Chilean population during the productive transformation. Modernization processes such as increased education and access to fertility control contributed to an increase in the number of highly educated women in nonmanual occupations in Santiago, but have not significantly influenced the volume or direction of female migration or modified the disadvantageous occupational profile of migrant women. Gender considerations including cultural norms governing female sexual behavior and nuptiality appear to exercise a decisive influence on the occupational status of migrant women in Santiago. Low status, single women migrating to Santiago have been concentrated in domestic service in part because of their need to find work providing safe living quarters. After 1975, migrant women encountered an increasing proportion of urban women working and looking for work and a structural transformation of domestic service marked by massive absorption of

  16. 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.

  17. Economic Effects of Migration from Poland to the UK

    Directory of Open Access Journals (Sweden)

    Mihaela Simionescu

    2017-08-01

    Full Text Available Considering that large numbers of the EU-8 immigrants was a strong argument for the Brexit, the objective of this paper is to assess some economic effects of migration from Poland to the UK for both countries. Intensive emigration of the Poles to the UK since 2004 negatively affected Poland’s economic growth in the long run, but it also reduced tensions at the labour market by decreasing the unemployment rate. On the other hand, the increase in Polish immigrants in the UK did not significantly affect economic growth and unemployment rate in the destination country in the short run in the period 2004-2015. A significance influence was observed only in the long run, when the UK economic growth decreased, but the pressures on the labour market significantly reduced. From these empirical findings, some policy recommendations are required for both countries: for Poland, migration policies to promote the return of migrants and more efficient utilization of labour force, while for the UK – shaping a more flexible labour market.

  18. Do American dippers obtain a survival benefit from altitudinal migration?

    Directory of Open Access Journals (Sweden)

    David J Green

    Full Text Available Studies of partial migrants provide an opportunity to assess the cost and benefits of migration. Previous work has demonstrated that sedentary American dippers (residents have higher annual productivity than altitudinal migrants that move to higher elevations to breed. Here we use a ten-year (30 period mark-recapture dataset to evaluate whether migrants offset their lower productivity with higher survival during the migration-breeding period when they occupy different habitat, or early and late-winter periods when they coexist with residents. Mark-recapture models provide no evidence that apparent monthly survival of migrants is higher than that of residents at any time of the year. The best-supported model suggests that monthly survival is higher in the migration-breeding period than winter periods. Another well-supported model suggested that residency conferred a survival benefit, and annual apparent survival (calculated from model weighted monthly apparent survival estimates using the Delta method of residents (0.511 ± 0.038SE was slightly higher than that of migrants (0.487 ± 0.032. Winter survival of American dippers was influenced by environmental conditions; monthly apparent survival increased as maximum daily flow rates increased and declined as winter temperatures became colder. However, we found no evidence that environmental conditions altered differences in winter survival of residents and migrants. Since migratory American dippers have lower productivity and slightly lower survival than residents our data suggests that partial migration is likely an outcome of competition for limited nest sites at low elevations, with less competitive individuals being forced to migrate to higher elevations in order to breed.

  19. Lipogems Product Treatment Increases the Proliferation Rate of Human Tendon Stem Cells without Affecting Their Stemness and Differentiation Capability.

    Science.gov (United States)

    Randelli, Pietro; Menon, Alessandra; Ragone, Vincenza; Creo, Pasquale; Bergante, Sonia; Randelli, Filippo; De Girolamo, Laura; Alfieri Montrasio, Umberto; Banfi, Giuseppe; Cabitza, Paolo; Tettamanti, Guido; Anastasia, Luigi

    2016-01-01

    Increasing the success rate of rotator cuff healing remains tremendous challenge. Among many approaches, the possibility of activating resident stem cells in situ, without the need to isolate them from biopsies, could represent valuable therapeutic strategy. Along this line, it has been recently demonstrated that lipoaspirate product, Lipogems, contains and produces growth-factors that may activate resident stem cells. In this study, human tendon stem cells (hTSCs) from the rotator cuff were cocultured in a transwell system with the Lipogems lipoaspirate product and compared to control untreated cells in terms of cell proliferation, morphology, stem cell marker and VEGF expression, and differentiation and migration capabilities. Results showed that the Lipogems product significantly increases the proliferation rate of hTSCs without altering their stemness and differentiation capability. Moreover, treated cells increase the expression of VEGF, which is crucial for the neovascularization of the tissue during the healing process. Overall, this study supports that directly activating hTSCs with the Lipogems lipoaspirate could represent a new practical therapeutic approach. In fact, obtaining a lipoaspirate is easier, safer, and more cost-effective than harvesting cells from tendon or bone marrow biopsies, expanding them in GMP facility and then reinjecting them in the patient.

  20. Lipogems Product Treatment Increases the Proliferation Rate of Human Tendon Stem Cells without Affecting Their Stemness and Differentiation Capability

    Directory of Open Access Journals (Sweden)

    Pietro Randelli

    2016-01-01

    Full Text Available Increasing the success rate of rotator cuff healing remains tremendous challenge. Among many approaches, the possibility of activating resident stem cells in situ, without the need to isolate them from biopsies, could represent valuable therapeutic strategy. Along this line, it has been recently demonstrated that lipoaspirate product, Lipogems, contains and produces growth-factors that may activate resident stem cells. In this study, human tendon stem cells (hTSCs from the rotator cuff were cocultured in a transwell system with the Lipogems lipoaspirate product and compared to control untreated cells in terms of cell proliferation, morphology, stem cell marker and VEGF expression, and differentiation and migration capabilities. Results showed that the Lipogems product significantly increases the proliferation rate of hTSCs without altering their stemness and differentiation capability. Moreover, treated cells increase the expression of VEGF, which is crucial for the neovascularization of the tissue during the healing process. Overall, this study supports that directly activating hTSCs with the Lipogems lipoaspirate could represent a new practical therapeutic approach. In fact, obtaining a lipoaspirate is easier, safer, and more cost-effective than harvesting cells from tendon or bone marrow biopsies, expanding them in GMP facility and then reinjecting them in the patient.

  1. Social, economic and demographic factors relating to interregional migration in the Philippines: 1970-1980.

    Science.gov (United States)

    Llasa, R N

    1982-10-01

    The study attempts to identify the different social, economic, and demographic factors relating to interregional migration in the Philippines for the decade 1970-1980. The dependent variable used is the regional net migration rate estimated through the national growth rate method. Using the rank order correlation technique, the relationship between the dependent variable and the different independent variables were determined. It is found that the following variables were positively related to interregional migration: percentage of 20-29 year old population, previous in-migrants, median family income, land area, primacy index, level of urbanization, level of education, and percentage of never married population. However, the first 3 variables mentioned seem to be the most significant determinants of regional net migration rates, which indicates that net migration in the Philippines during the last decade tends to be more dependent upon previous migration patterns and less dependent upon current socioeconomic development.

  2. Fertility and migration in the heart of the industrial revolution.

    Science.gov (United States)

    Oris, M

    1996-01-01

    This study examines demographic growth and change in Tilleur in the valley of Meuse in Belgium during 1807-80 during the process of industrialization and urbanization. The proportion of immigrants (foreigners and Flemings) increased from 15% in 1807 to 65% in 1856. After 1856, population and industrial growth stabilized. During 1856-66 the proportion of natives stabilized, and the proportion of Flemings increased. It is argued that in Tilleur there were two phases: a foundation phase of industrial and population growth and a phase of maturation with decreased non-native population and greater similarity between groups. Immigrants contributed to the birth rate in greater proportions than their proportion in the population of Tilleur. During 1847-66 native population increased annually from 2.4% to 3.8%. Migrants' annual increases were diminished by the effects of mortality but expanded by the influence of in-migration. During 1857-66 the proportion of foreigners declined and marked the transition to a new phase. During 1830-66 the sex ratio grew from 93 to 119. During the Industrial Revolution in Tilleur, women shifted from outnumbering to undernumbering men. The iron and coal in the region attracted men. The sex ratio among the Flemish was 214 in 1866. In 1830 the proportion of fertile women was higher among immigrants and declined thereafter. Age at marriage rose for natives and declined for immigrants. The native population structure by sex, age, and marriage did not favor the birth rate. During 1866-80 the birth rate of foreign immigrants and rural natives declined, the birth rate of natives doubled, and the gap between these two groups narrowed. The changes among immigrants during the foundation phase led to fertility decline in the maturation phase. Marriage and migration interactions linked the industrial revolution with the demographic transition.

  3. Probabilistic income-maximizing behavior in regional migration: an empirical test.

    Science.gov (United States)

    Weinstein, R I; Evans, R D

    1980-01-01

    "This paper provides an empirical test of the hypothesis that migrants consider income risk in their evaluation of the returns to migration in that higher levels of income risk for a given region reduce the rate of net migration into that region." Theoretical approaches to the incorporation of income risk in migration models are first considered, and alternative approaches are then tested using data on white and nonwhite net migration in the United States between 1960 and 1970. The results indicate support for the hypothesis that the extent of net migration is inversely affected by income risk. excerpt

  4. Migration of Phthalates from Plastic Containers into Soft Drinks and Mineral Water

    Directory of Open Access Journals (Sweden)

    Jasna Bošnir

    2007-01-01

    Full Text Available The aim of this study was to determine the level of phthalate migration from plastic containers to soft drinks and mineral water and to identify a possible relationship between the amount and type of phthalate migration, type of preservative used, and the pH of the sample. The analysis included 45 samples of products packed in containers made from polyethylene terephthalate. The samples were divided into 5 groups: group 1 (N=9, soft drinks preserved with orthophosphoric acid; group 2 (N=14, soft drinks preserved with Na-benzoate; group 3 (N=5, soft drinks preserved with K-sorbate; group 4 (N=8, soft drinks preserved with a combination of Na-benzoate and K-sorbate; and group 5 (N=9, mineral water without preservatives. The samples were analyzed by the method of gas chromatography, with a detection limit of 0.005 μg/L. The mean pool phthalate level and mean pH value were 91.67 μg/L and 2.82±0.30 in group 1; 116.93 μg/L and 2.75±0.32 in group 2; 819.40 μg/L and 2.88±0.15 in group 3; 542.63 μg/L and 2.82±0.54 in group 4; and 20.22 μg/L and 5.82±1.26 in group 5, respectively. The highest rate of migration to soft drinks was recorded for dimethyl phthalate, ranging from 53.51 to 92.73 %, whereas dibutyl phthalate and diethylhexyl phthalate showed highest rate of migration to the mineral water (56.04 and 43.42 %, respectively. The highest level of phthalate migration from plastic containers to soft drinks was found in the products preserved with K-sorbate. The rate of phthalate migration appears to be influenced also by the drink pH, i.e. the lower the pH value, the greater the phthalate migration. Dimethyl phthalate showed highest migration to preserved drinks as an acidic medium, which might stimulate modification in the composition of plastic containers according to the type and composition of the product. Additional studies in a greater number of samples are needed. Although the phthalate levels measured in these samples pose no risk for

  5. Register study of migrants' hospitalization in Norway: world region origin, reason for migration, and length of stay.

    Science.gov (United States)

    Elstad, Jon Ivar

    2016-07-26

    The proportion of migrants and refugees increase in many populations. Health planners have to consider how migration will influence demand for health care. This study explores how migrants' geographical origin, reason for migration, and duration of residence are associated with admission rates to somatic hospitals in Norway. Sociodemographic information on all individuals residing in Norway at the start of 2008 was linked to data on all admissions to somatic hospitals during 2008-2011. Migrants, age 30-69, who had come to Norway during 1970-2007 (N = 217,907), were classified into seven world region origins and compared with native Norwegians of the same age (N = 2,181,948). Any somatic hospital stay 2008-2011 and number of hospital admissions 2008-2011 per 1000 personyears for a set of somatic diagnoses were analyzed by age and gender standardized rates, linear probability models, and Poisson regression. In the native Norwegian sample, 28.7 % had at least one admission 2008-2011, and there were 116 admissions per 1000 personyears. Corresponding age and gender adjusted figures for the migrant sample were 27.0 % and 103 admissions. Admission rates varied with migrants' geographical origin, with relatively many admissions among migrants from West and South Asia and relatively few admissions among migrants from Western, East European, and Other Asian countries. Hospitalization varied strongly with reason for migration, with low admission rates for recent work migrants and high admission rates for recent refugees. Admission rates tended to move towards the level among native Norwegians with increasing length of stay. Among longstanding migrants (arrival period 1970-1989), admission rates were close to the levels of native Norwegians for most analyzed migrant categories. Both world region origin, reason for migration, and duration of residence are important sources for variations in migrants' utilization of somatic hospitals. Forecasts about migrants' use of

  6. Involvement of PUMA in pericyte migration induced by methamphetamine.

    Science.gov (United States)

    Zhang, Yanhong; Zhang, Yuan; Bai, Ying; Chao, Jie; Hu, Gang; Chen, Xufeng; Yao, Honghong

    2017-07-01

    Mounting evidence indicates that methamphetamine causes blood-brain barrier damage, with emphasis on endothelial cells. The role of pericytes in methamphetamine-induced BBB damage remains unknown. Our study demonstrated that methamphetamine increased the migration of pericytes from the endothelial basement membrane. However, the detailed mechanisms underlying this process remain poorly understood. Thus, we examined the molecular mechanisms involved in methamphetamine-induced pericyte migration. The results showed that exposure of C3H/10T1/2 cells and HBVPs to methamphetamine increased PUMA expression via activation of the sigma-1 receptor, MAPK and Akt/PI3K pathways. Moreover, methamphetamine treatment resulted in the increased migration of C3H/10T1/2 cells and HBVPs. Knockdown of PUMA in pericytes transduced with PUMA siRNA attenuated the methamphetamine-induced increase in cell migration through attenuation of integrin and tyrosine kinase mechanisms, implicating a role of PUMA in the migration of C3H/10T1/2 cells and HBVPs. This study has demonstrated that methamphetamine-mediated pericytes migration involves PUMA up-regulation. Thus, targeted studies of PUMA could provide insights to facilitate the development of a potential therapeutic approach for alleviation of methamphetamine-induced pericyte migration. Copyright © 2017. Published by Elsevier Inc.

  7. Risk Factors for Migration, Fracture, and Dislocation of Pancreatic Stents

    Directory of Open Access Journals (Sweden)

    Yoshiaki Kawaguchi

    2015-01-01

    Full Text Available Aim. To analyze the risk factors for pancreatic stent migration, dislocation, and fracture in chronic pancreatitis patients with pancreatic strictures. Materials and Methods. Endoscopic stent placements (total 386 times were performed in 99 chronic pancreatitis patients with pancreatic duct stenosis at our institution between April 2006 and June 2014. We retrospectively examined the frequency of stent migration, dislocation, and fracture and analyzed the patient factors and stent factors. We also investigated the retrieval methods for migrated and fractured stents and their success rates. Results. The frequencies of stent migration, dislocation, and fracture were 1.5% (5/396, 0.8% (3/396, and 1.2% (4/396, respectively. No significant differences in the rates of migration, dislocation, or fracture were noted on the patient factors (etiology, cases undergoing endoscopic pancreatic sphincterotomy, location of pancreatic duct stenosis, existence of pancreatic stone, and approach from the main or minor papilla and stent factors (duration of stent placement, numbers of stent placements, stent shape, diameter, and length. Stent retrieval was successful in all cases of migration. In cases of fractured stents, retrieval was successful in 2 of 4 cases. Conclusion. Stent migration, fracture, and dislocation are relatively rare, but possible complications. A good understanding of retrieval techniques is necessary.

  8. The effect of agricultural price-support policies on interregional and rural-to-urban migration in Korea: 1976-1980.

    Science.gov (United States)

    Shefer, D

    1987-08-01

    The impact of rice price-support policies, designed to increase farmers' income and reduce rural-urban migration in the Republic of Korea, is examined for the period 1976-1980 using a polytomous logistic model. "Our findings revealed that the elasticity of migration with respect to rice yield per origin farm household is positive and is significantly different from zero. The elasticities of migration with respect to rate of urbanization, particularly urban concentration-agglomeration, and population size of the destination are also positive and are significantly different from zero.... Our findings questioned the wisdom of employing rice price price-support programs as a viable policy for reducing interregional and rural-to-urban migration in Korea." excerpt

  9. Outward migration may alter population dynamics and income inequality

    Science.gov (United States)

    Shayegh, Soheil

    2017-11-01

    Climate change impacts may drive affected populations to migrate. However, migration decisions in response to climate change could have broader effects on population dynamics in affected regions. Here, I model the effect of climate change on fertility rates, income inequality, and human capital accumulation in developing countries, focusing on the instrumental role of migration as a key adaptation mechanism. In particular, I investigate how climate-induced migration in developing countries will affect those who do not migrate. I find that holding all else constant, climate change raises the return on acquiring skills, because skilled individuals have greater migration opportunities than unskilled individuals. In response to this change in incentives, parents may choose to invest more in education and have fewer children. This may ultimately reduce local income inequality, partially offsetting some of the damages of climate change for low-income individuals who do not migrate.

  10. Quantifying the population effects of vaccination and migration on hepatitis A seroepidemiology in Australia.

    Science.gov (United States)

    Jayasundara, Duleepa; Hui, Ben B; Regan, David G; Heywood, Anita E; MacIntyre, C Raina; Wood, James G

    2017-09-18

    Since licensure of hepatitis A vaccine in Australia in 1994, infection rates have declined to record lows. Cross-sectional serosurveys conducted over this period meanwhile have shown rising population immunity, particularly in young to middle-aged Australians. In this study, we performed a retrospective birth cohort analysis to estimate the contributions of infection, migration and vaccination towards increased levels of age specific hepatitis A seroprevalence in Australia. When aggregated across age, we find that two-thirds of the increase in population seropositivity (67.04%) between 1994 and 2008 was due to vaccination, just under one-third due to migration, with a negligible contribution from infection (hepatitis A vaccine recommendations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Inter-communal migrations in Switzerland: a "mountain factor"?

    Directory of Open Access Journals (Sweden)

    Martin Camenisch

    2011-05-01

    Full Text Available To go beyond existing publications on inter-communal migrations in Switzerland, this paper focuses on a comparison of behaviours between communes of different types: rural, urban, mountain, tourist, etc. It is based on two sets of data: the Swiss Population Census (1999-2008 and the Swiss Household Panel. This paper has two main conclusions of this paper: first, contrary to the dominant practice which compares communes according to their respective difference between in-migration and out-migration rate, this paper highlights the contrast between “warm” and “cold” communes (comparing the migration rate itself; there is a "mountain factor" which means that most inter-communal migrations occur within the mountain zone, or within the Swiss Plateau.Prolongeant les publications existantes sur les migrations intercommunales en Suisse, l'article focalise son attention sur les comportements différenciés des communes selon les types dont elles relèvent: urbaines, montagnardes, touristiques, rurales, etc. Il repose sur l'utilisation des données du recensement fédéral de la population (1999-2008 et sur celles du Panel Suisse des Ménages. Il parvient à deux conclusions principales: les communes que l'on compare le plus souvent en fonction de leur bilan migratoire, peuvent aussi être utilement différenciées selon qu'elles sont « chaudes » ou « froides » (avec un taux de migration fort ou faible, quelque soit le solde; il existe un "effet montagne" qui signifie ici la propension des migrations à se faire principalement à l'intérieur de la zone de montagne suisse ou à l'intérieur du Plateau suisse.

  12. Effects of moisture migration on shrinkage, pore pressure and other concrete properties

    International Nuclear Information System (INIS)

    Chapman, D.A.; England, G.L.

    1977-01-01

    This work investigates the uniaxial migration of moisture in long, upright, limestone concrete cylinders, sealed at the base and sides, and open at the top. The design represents a section through a concrete pressure vessel wall. The cylinders are subjected to a sustained temperature difference between their ends, with maximum temperatures between 105 0 C and 200 0 C. Readings of pore pressure, water content and temperature are taken at various positions along the axis of the cylinders. In one cylinder, transverse and longitudinal shrinkage readings are also recorded. The results for the cylinders show that moisture migration is away from the hot face of the specimens causing reduction in both pore pressure and water content values in this region. The moisture migration creates a drying front which moves slowly up the specimens. The rate at which this drying front, moves is influenced by the base temperature, the magnitude of temperature and pressure gradients and the coefficient of permeability of the concrete. Samples taken from the hot side of the drying front show a considerable increase in the coefficient of permeability, and Scanning Electron Microscope photographs of the microstructure show both a break-up and reduction in size of the hydration products. The experiments reported indicate that when the hot inner face temperature of a concrete pressure vessel is increased above 100 0 C, the drying rate inside the wall increases considerably, However, it is unlikely pressure vessels of the size currently in use will ever completely dry out. (Auth.)

  13. Gas migration through cement slurries analysis: A comparative laboratory study

    Directory of Open Access Journals (Sweden)

    Arian Velayati

    2015-12-01

    Full Text Available Cementing is an essential part of every drilling operation. Protection of the wellbore from formation fluid invasion is one of the primary tasks of a cement job. Failure in this task results in catastrophic events, such as blow outs. Hence, in order to save the well and avoid risky and operationally difficult remedial cementing, slurry must be optimized to be resistant against gas migration phenomenon. In this paper, performances of the conventional slurries facing gas invasion were reviewed and compared with modified slurry containing special gas migration additive by using fluid migration analyzer device. The results of this study reveal the importance of proper additive utilization in slurry formulations. The rate of gas flow through the slurry in neat cement is very high; by using different types of additives, we observe obvious changes in the performance of the cement system. The rate of gas flow in neat class H cement was reported as 36000 ml/hr while the optimized cement formulation with anti-gas migration and thixotropic agents showed a gas flow rate of 13.8 ml/hr.

  14. SHARPIN Regulates Uropod Detachment in Migrating Lymphocytes

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    Jeroen Pouwels

    2013-11-01

    Full Text Available SHARPIN-deficient mice display a multiorgan chronic inflammatory phenotype suggestive of altered leukocyte migration. We therefore studied the role of SHARPIN in lymphocyte adhesion, polarization, and migration. We found that SHARPIN localizes to the trailing edges (uropods of both mouse and human chemokine-activated lymphocytes migrating on intercellular adhesion molecule-1 (ICAM-1, which is one of the major endothelial ligands for migrating leukocytes. SHARPIN-deficient cells adhere better to ICAM-1 and show highly elongated tails when migrating. The increased tail lifetime in SHARPIN-deficient lymphocytes decreases the migration velocity. The adhesion, migration, and uropod defects in SHARPIN-deficient lymphocytes were rescued by reintroducing SHARPIN into the cells. Mechanistically, we show that SHARPIN interacts directly with lymphocyte-function-associated antigen-1 (LFA-1, a leukocyte counterreceptor for ICAM-1, and inhibits the expression of intermediate and high-affinity forms of LFA-1. Thus, SHARPIN controls lymphocyte migration by endogenously maintaining LFA-1 inactive to allow adjustable detachment of the uropods in polarized cells.

  15. The mitochondrial uniporter controls fight or flight heart rate increases.

    Science.gov (United States)

    Wu, Yuejin; Rasmussen, Tyler P; Koval, Olha M; Joiner, Mei-Ling A; Hall, Duane D; Chen, Biyi; Luczak, Elizabeth D; Wang, Qiongling; Rokita, Adam G; Wehrens, Xander H T; Song, Long-Sheng; Anderson, Mark E

    2015-01-20

    Heart rate increases are a fundamental adaptation to physiological stress, while inappropriate heart rate increases are resistant to current therapies. However, the metabolic mechanisms driving heart rate acceleration in cardiac pacemaker cells remain incompletely understood. The mitochondrial calcium uniporter (MCU) facilitates calcium entry into the mitochondrial matrix to stimulate metabolism. We developed mice with myocardial MCU inhibition by transgenic expression of a dominant-negative (DN) MCU. Here, we show that DN-MCU mice had normal resting heart rates but were incapable of physiological fight or flight heart rate acceleration. We found that MCU function was essential for rapidly increasing mitochondrial calcium in pacemaker cells and that MCU-enhanced oxidative phoshorylation was required to accelerate reloading of an intracellular calcium compartment before each heartbeat. Our findings show that MCU is necessary for complete physiological heart rate acceleration and suggest that MCU inhibition could reduce inappropriate heart rate increases without affecting resting heart rate.

  16. QUALIFIED VERSION OF MIGRATION: BRAIN DRAIN

    Directory of Open Access Journals (Sweden)

    Ayhan GENCLER

    2009-07-01

    Full Text Available Though globalization suggests an international exchange of people besides goods and capital, developed countries often tended to put forward some restrictions on the migration of workers from developed countries. However, there has been an increase in skilled international migration especially during the last two decades. Skilled international migration or brain drain points out the emigration of educated and highly skilled workers. It seems that, in general, developing or underdeveloped countries experience the negative consequences of the brain drain and suffer from the decreases in their human capital. The paper explains the phenomenon of skilled international migration, or brain drain, and summarizes the main global trends in this area.

  17. Kinetics of a Migration-Driven Aggregation-Fragmentation Process

    Institute of Scientific and Technical Information of China (English)

    ZHUANG You-Yi; LIN Zhen-Quan; KE Jian-Hong

    2003-01-01

    We propose a reversible model of the migration-driven aggregation-fragmentation process with the sym-metric migration rate kernels K(k;j) = K'(k;j) = λkjv and the constant aggregation rates I1, I2 and fragmentationrates J1, J2. Based on the mean-field theory, we investigate the evolution behavior of the aggregate size distributions inseveral cases with different values of index v. We find that the fragmentation reaction plays a more important role in the kinetic behaviors of the system than the aggregation and migration. When J1 = 0 and J2 = 0, the aggregate sizedistributions ak(t) and bk(t) obey the conventional scaling law, while when J1 > 0 and J2 > 0, they obey the modifiedscaling law with an exponential scaling function. The total mass of either species remains conserved.

  18. On the migration of uranium isotopes in sandstone aquifers

    International Nuclear Information System (INIS)

    Froehlich, K.; Gellermann, R.

    1982-01-01

    Measurements of natural 238 U and 234 U activity in groundwater of sandstone aquifers have been used to study the migration of these uranium isotopes. Regarding the uranium exchange between liquid phase and rock surface during migration, two different models were applied for evaluating the experimental results. Values of corresponding parameters (retardation factor K, removal rate R) reflecting different behaviour concerning this exchange were determined. For example, the values obtained for 238 U in a Triassic sandstone aquifer of the GDR are K = 8.6 x 10 6 and R = 1.3 x 10 -3 a -1 , respectively. It was found that, under the conditions of the sandstone aquifer concerned, the removal rate model is better suited for calculating uranium-isotope migration in groundwater. (author)

  19. Overexpression of CXCR4 on human CD34+ progenitors increases their proliferation, migration, and NOD/SCID repopulation.

    Science.gov (United States)

    Kahn, Joy; Byk, Tamara; Jansson-Sjostrand, Lottie; Petit, Isabelle; Shivtiel, Shoham; Nagler, Arnon; Hardan, Izhar; Deutsch, Varda; Gazit, Zulma; Gazit, Dan; Karlsson, Stefan; Lapidot, Tsvee

    2004-04-15

    A major limitation to clinical stem cell-mediated gene therapy protocols is the low levels of engraftment by transduced progenitors. We report that CXCR4 overexpression on human CD34+ progenitors using a lentiviral gene transfer technique helped navigate these cells to the murine bone marrow and spleen in response to stromal-derived factor 1 (SDF-1) signaling. Cells overexpressing CXCR4 exhibited significant increases in SDF-1-mediated chemotaxis and actin polymerization compared with control cells. A major advantage of CXCR4 overexpression was demonstrated by the ability of transduced CD34+ cells to respond to lower, physiologic levels of SDF-1 when compared to control cells, leading to improved SDF-1-induced migration and proliferation/survival, and finally resulting in significantly higher levels of in vivo repopulation of nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice including primitive CD34+/CD38(-/low) cells. Importantly, no cellular transformation was observed following transduction with the CXCR4 vector. Unexpectedly, we documented lack of receptor internalization in response to high levels of SDF-1, which can also contribute to increased migration and proliferation by the transduced CD34+ cells. Our results suggest CXCR4 overexpression for improved definitive human stem cell motility, retention, and multilineage repopulation, which could be beneficial for in vivo navigation and expansion of hematopoietic progenitors.

  20. Pre-migration trauma and HIV-risk behavior.

    Science.gov (United States)

    Steel, Jennifer; Herlitz, Claes; Matthews, Jesse; Snyder, Wendy; Mazzaferro, Kathryn; Baum, Andy; Theorell, Töres

    2003-03-01

    This study examined the relationship between pre-migration trauma and HIV-risk behavior in refugees from sub-Saharan Africa. The sample comprised 122 persons who had emigrated from sub-Saharan Africa and were currently residing in Sweden. Qualitative methods including individual interviews, focus groups, and interviews with key informants addressed questions regarding trauma experience and HIV-risk behavior. A history of pre-migration trauma was found to be associated with HIV-risk behavior. According to the participants, symptoms associated with post-traumatic stress disorder, depression, adjustment disorder, and substance use mediated the relationship between pre-migration trauma and sexual risk behavior. In contrast, a minority of the participants who reported pre-migration trauma but not psychological sequelae, or experienced post-traumatic growth, reported safer sexual practices. It appears that for some individuals, pre-migration trauma resulted in psychiatric sequelae, which may increase an individual's risk to be infected with HIV. Interventions targeted at individuals at increased risk (i.e. pre-migration trauma with unresolved psychiatric symptomatology) may facilitate the prevention of HIV and other sexually transmitted diseases in this population. Integration of multiple psychosocial and health issues is recommended for comprehensive treatment and prevention programs.

  1. An analysis of interprovincial migration in Vietnam from 1989 to 2009

    Directory of Open Access Journals (Sweden)

    Le Thi Kim Anh

    2012-12-01

    Full Text Available Background: In Vietnam, reports either present general patterns of internal migration or the migration characteristics of specific subgroups. Reports are often based on small numbers and do not examine the relationships between socioeconomic factors and migration. Different reports classify migrant populations differently, presenting difficulties for researchers and policymakers to gain a consistent picture of migration (particularly of interprovincial migration and limiting the ability of policymakers to plan services appropriately. This study describes the characteristics of all migrants in Vietnam, focusing on interprovincial migrants, and examines age and sex trends and correlations among in-migration, urbanization, and individual income. Methods: We analyzed data from the 15% sample survey in the 2009 Population and Housing Census, the 3% sample in the 1999 national census, the 5% sample in the 1989 national census, and selected data from the 2008 Vietnam Household Living Standards Survey. Logistic regression was used to identify socioeconomic factors related to migration. Results: In 2009, of 6.7 million internal migrants (approximately 6.5% of the total population, 3.4 million were interprovincial migrants. Three notable trends were observed between 1989 and 2009: (i the total population is characterized by increasing proportions of migrants; (ii the proportion of female migrants is growing; and (iii the average age of migrants is decreasing. Socioeconomic factors related to interprovincial migration include provincial economic status (monthly income per capita: OR = 4.62, p = 0.005 and urbanization (proportion of urban population: OR = 3.47, p = 0.019, suggesting that provinces with high monthly income per capita and urbanization are more likely to have higher rates of in-migration. Conclusion: These findings reflect the effects of unequally growing labor markets in Vietnamese provinces on migration, and are suggestive of infrastructure

  2. An analysis of interprovincial migration in Vietnam from 1989 to 2009.

    Science.gov (United States)

    Anh, Le Thi Kim; Hoang Vu, Lan; Bonfoh, Bassirou; Schelling, Esther

    2012-12-31

    Background: In Vietnam, reports either present general patterns of internal migration or the migration characteristics of specific subgroups. Reports are often based on small numbers and do not examine the relationships between socioeconomic factors and migration. Different reports classify migrant populations differently, presenting difficulties for researchers and policymakers to gain a consistent picture of migration (particularly of interprovincial migration) and limiting the ability of policymakers to plan services appropriately. This study describes the characteristics of all migrants in Vietnam, focusing on interprovincial migrants, and examines age and sex trends and correlations among in-migration, urbanization, and individual income.Methods: We analyzed data from the 15% sample survey in the 2009 Population and Housing Census, the 3% sample in the 1999 national census, the 5% sample in the 1989 national census, and selected data from the 2008 Vietnam Household Living Standards Survey. Logistic regression was used to identify socioeconomic factors related to migration.Results: In 2009, of 6.7 million internal migrants (approximately 6.5% of the total population), 3.4 million were interprovincial migrants. Three notable trends were observed between 1989 and 2009: (i) the total population is characterized by increasing proportions of migrants; (ii) the proportion of female migrants is growing; and (iii) the average age of migrants is decreasing. Socioeconomic factors related to interprovincial migration include provincial economic status (monthly income per capita: OR = 4.62, p = 0.005) and urbanization (proportion of urban population: OR = 3.47, p = 0.019), suggesting that provinces with high monthly income per capita and urbanization are more likely to have higher rates of in-migration.Conclusion: These findings reflect the effects of unequally growing labor markets in Vietnamese provinces on migration, and are suggestive of infrastructure improvements and

  3. Cs-137 migration in soil near NPPs

    International Nuclear Information System (INIS)

    Silant'ev, A.N.; Shkuratova, I.G.; Khatskevich, R.N.

    1984-01-01

    A convective-diffusion model has been employed for describing Cs-137 migration in soil. The migration parameters were determined by comparing the calculated vertical distribution profiles with the experimental ones. The migration parameters dependence on the soil state has been studied. Cs-137 penetration rate was found to be function of the soil type, surface state, soil wetness and orography. The obtained values are presented. A method is suggested for revealing the soil surface contamination by Cs-137 produced during NPP operation with distinguishing it from the global contamination background. For this purpose Cs-137 content in the upper 5 mm soil layer is estimated [ru

  4. Dynamics of urban population growth in Nigeria: The role of repeated migration.

    Science.gov (United States)

    Adepoju, A

    1976-02-01

    The paper examines the direct contribution of migration to the growth of the urban population both in terms of its mobility and stability components with special reference to Western Nigeria. The basis of the paper is a survey of urban migration conducted by the author in 1971-1972; the findings are supplemented where necessary by the 1952-1953 and 1963 census figures. Migration is a major factor in the growth of the urban population. The direct contribution by migrants to such growth can be traced to the following groups: the initial streams of migrants, the follow-up migrants and the potentially mobile migrants attracted from the migrants' communities of origin to the towns. Repeated migration by some migrants, particularly the young, the educated and the white collar-workers, are also major factors in the urban population growth. Such repeated migrations are predominantly urban to urban or turnover moves. The high mobility rate among a group of migrants tends to conceal the relative stability among the migrant population as a whole. Repeated migrants usually stay between 3 and 5 years at each destination, before moving on. A substantial proportion of migrants, mainly farmers, the less educated and the old, are relatively stable in the survey towns (Ife and Oshogho). The urban residence ration indices also indicate an increase in the rate of immigration, mainly of young persons, to the towns. The youthful age structure, the age selectivity in migration and the marital status of the young migrants tend to exacerbate the masculinity in the form of unbalanced sex ratio prevailing in most urban centers. The urban population is unlikely to be stable. The tendency for old migrants of rural origin to return to their villages at the end of their migration career and for contemporary migrants to consist predominantly of youths, will for the next generation or 2 lead to a young and unstable urban population.

  5. Rural Education and Out-Migration: The Case of a Coastal Community

    Science.gov (United States)

    Corbett, Michael

    2005-01-01

    In this article, I report on findings from a case study examining the relationship between formal education and out-migration in a Canadian coastal community from the early 1960s to the late 1990s. Although high rates of village-level out-migration were chronic, most migration trajectories were short-range. Contrary to large-scale quantitative…

  6. Theories of international labor migration: an overview.

    Science.gov (United States)

    Stahl, C W

    1995-01-01

    "Emigration pressures are primarily the result of increasing inequalities between countries which, in turn, are the result of factors internal to less developed countries and their relations with developed countries. Both micro (neoclassical) and macrostructural theories of migration are reviewed. It is argued that the neoclassical theory of migration is often unjustly criticized and is sufficiently robust to incorporate those structural considerations which are at the core of macrostructural theories. Moreover, the neoclassical theory, with slight modification, can incorporate the ¿new economics of migration.' The major empirical problem confronting models of international labor migration is that migration flows are constrained by immigration policy. This policy, in turn, is influenced by various special interest groups. The direction and form of migration flows is conditioned by contemporary and historical relationships between source and destination countries." excerpt

  7. Amplification or suppression: Social networks and the climate change—migration association in rural Mexico

    Science.gov (United States)

    Riosmena, Fernando; Hunter, Lori M.; Runfola, Daniel M.

    2015-01-01

    Increasing rates of climate migration may be of economic and national concern to sending and destination countries. It has been argued that social networks – the ties connecting an origin and destination – may operate as “migration corridors” with the potential to strongly facilitate climate change-related migration. This study investigates whether social networks at the household and community levels amplify or suppress the impact of climate change on international migration from rural Mexico. A novel set of 15 climate change indices was generated based on daily temperature and precipitation data for 214 weather stations across Mexico. Employing geostatistical interpolation techniques, the climate change values were linked to 68 rural municipalities for which sociodemographic data and detailed migration histories were available from the Mexican Migration Project. Multi-level discrete-time event-history models were used to investigate the effect of climate change on international migration between 1986 and 1999. At the household level, the effect of social networks was approximated by comparing the first to the last move, assuming that through the first move a household establishes internal social capital. At the community level, the impact of social capital was explored through interactions with a measure of the proportion of adults with migration experience. The results show that rather than amplifying, social capital may suppress the sensitivity of migration to climate triggers, suggesting that social networks could facilitate climate change adaptation in place. PMID:26692656

  8. Migration between the United States and Canada: a study of labour market adjustment.

    Science.gov (United States)

    Brox, J A

    1983-01-01

    "... The main purpose of this study is to examine population flows between Canada and the United States [from mid-1947 to mid-1972] in order to investigate the degree to which labour market adjustment is aided by such movements. [The author considers] several functional forms of the migration relationship in an attempt to empirically determine how the decision to migrate is formed. [He also compares the] results with those obtained by Courchene...for Canadian interprovincial migration in an effort to compare the effects of international and internal migration on labour market adjustment." It is found that "migration between the United States and Canada over the post-war period is an economic variable. In fact, [a] simple model employing differences in income levels and unemployment rates has been able to explain nearly ninety-five per cent of the variation in the migration rate." The author also notes that "although migration between Canada and the United States does occur in such a way as to aid labour market adjustment, it is not as efficient as internal migration." (summary in FRE, SPA) excerpt

  9. Q-Least Squares Reverse Time Migration with Viscoacoustic Deblurring Filters

    KAUST Repository

    Chen, Yuqing; Dutta, Gaurav; Dai, Wei; Schuster, Gerard T.

    2017-01-01

    Viscoacoustic least-squares reverse time migration (Q-LSRTM) linearly inverts for the subsurface reflectivity model from lossy data. Compared to the conventional migration methods, it can compensate for the amplitude loss in the migrated images because of the strong subsurface attenuation and can produce reflectors that are accurately positioned in depth. However, the adjoint Q propagators used for backward propagating the residual data are also attenuative. Thus, the inverted images from Q-LSRTM are often observed to have lower resolution when compared to the benchmark acoustic LSRTM images from acoustic data. To increase the resolution and accelerate the convergence of Q-LSRTM, we propose using viscoacoustic deblurring filters as a preconditioner for Q-LSRTM. These filters can be estimated by matching a simulated migration image to its reference reflectivity model. Numerical tests on synthetic and field data demonstrate that Q-LSRTM combined with viscoacoustic deblurring filters can produce images with higher resolution and more balanced amplitudes than images from acoustic RTM, acoustic LSRTM and Q-LSRTM when there is strong attenuation in the background medium. The proposed preconditioning method is also shown to improve the convergence rate of Q-LSRTM by more than 30 percent in some cases and significantly compensate for the lossy artifacts in RTM images.

  10. Q-Least Squares Reverse Time Migration with Viscoacoustic Deblurring Filters

    KAUST Repository

    Chen, Yuqing

    2017-08-02

    Viscoacoustic least-squares reverse time migration (Q-LSRTM) linearly inverts for the subsurface reflectivity model from lossy data. Compared to the conventional migration methods, it can compensate for the amplitude loss in the migrated images because of the strong subsurface attenuation and can produce reflectors that are accurately positioned in depth. However, the adjoint Q propagators used for backward propagating the residual data are also attenuative. Thus, the inverted images from Q-LSRTM are often observed to have lower resolution when compared to the benchmark acoustic LSRTM images from acoustic data. To increase the resolution and accelerate the convergence of Q-LSRTM, we propose using viscoacoustic deblurring filters as a preconditioner for Q-LSRTM. These filters can be estimated by matching a simulated migration image to its reference reflectivity model. Numerical tests on synthetic and field data demonstrate that Q-LSRTM combined with viscoacoustic deblurring filters can produce images with higher resolution and more balanced amplitudes than images from acoustic RTM, acoustic LSRTM and Q-LSRTM when there is strong attenuation in the background medium. The proposed preconditioning method is also shown to improve the convergence rate of Q-LSRTM by more than 30 percent in some cases and significantly compensate for the lossy artifacts in RTM images.

  11. Temperature-influenced energetics model for migrating waterfowl

    Science.gov (United States)

    Aagaard, Kevin; Thogmartin, Wayne E.; Lonsdorg, Eric V.

    2018-01-01

    Climate and weather affect avian migration by influencing when and where birds fly, the energy costs and risks of flight, and the ability to sense cues necessary for proper navigation. We review the literature of the physiology of avian migration and the influence of climate, specifically temperature, on avian migration dynamics. We use waterfowl as a model guild because of the ready availability of empirical physiological data and their enormous economic value, but our discussion and expectations are broadly generalizable to migratory birds in general. We detail potential consequences of an increasingly warm climate on avian migration, including the possibility of the cessation of migration by some populations and species. Our intent is to lay the groundwork for including temperature effects on energetic gains and losses of migratory birds with the expected consequences of increasing temperatures into a predictive modeling framework. To this end, we provide a simulation of migration progression exclusively focused on the influence of temperature on the physiological determinants of migration. This simulation produced comparable results to empirically derived and observed values for different migratory factors (e.g., body fat content, flight range, departure date). By merging knowledge from the arenas of avian physiology and migratory theory we have identified a clear need for research and have developed hypotheses for a path forward.

  12. The effect of migration on family structures in sub-Saharan Africa.

    Science.gov (United States)

    Okoth-ogendo, H W

    1989-06-01

    This paper assesses the effect of migration or family structures in sub-Saharan Africa, especially the effect of emigration on the reproduction, production, and social stability of the family in areas of origin in the predominantly agrarian communities of East and Southern Africa. Migration in precolonial Africa usually occurred for 1 of the following reasons: 1) the search by communities for new habitats and opportunities; 2) as a community response to droughts, floods, environmental degradation, and similar disasters; and 3) as a result of internecine wars, civil strife, and general hostilities. Thus, because of the collective nature of early migrations, the family unit maintained a much greater degree of social cohesion. The effects of the rise of the modern state in Africa on migration include 1) spatial limits of collective migration were frozen, 2) the colonial boundaries did not always correspond to cultural divisions, 3) both migration within colonial boundaries and individual migration became dominant, and 4) cyclical migration began. The end of colonialism resulted in 1) difficulties in creating strong and internally coherent nation states because of the uncertainty of national borders and 2) more cyclical migrants. The effects of migration on reproduction in the family during the colonial period include 17 extremely low fertility rates, 2) widespread domestic instability, and 3) exacerbation of moral decadence. Contemporary patterns of emigration have been far less disruptive, due in part to increased personal mobility and migration of the complete reproductive unit. The effects of migration on production include 1) depletion of labor for production; 2) women had to assume production functions, together with all their other responsibilities; and 3) very little cash or goods were available for remittance to areas of origin. Production and productivity among rural African families will continue to suffer as long as plantations, mines, and urban centers

  13. Decreased stage migration rate of early gastric cancer with a new reconstruction algorithm using dual-energy CT images: a preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Cen [Shanghai Jiao Tong University School of Medicine, Department of Radiology, Ruijin Hospital, Shanghai (China); First Affiliated Hospital of Soochow University, Department of Radiology, Suzhou (China); Zhang, Huan; Du, Lianjun; Pan, Zilai; Yan, Fuhua [Shanghai Jiao Tong University School of Medicine, Department of Radiology, Ruijin Hospital, Shanghai (China); Yan, Jing [Siemens Medical System, Shanghai (China); Wang, Baisong [Shanghai Jiao Tong University School of Medicine, Department of Biological Statistics, Shanghai (China)

    2017-02-15

    To evaluate the potential value of advanced monoenergetic images (AMEIs) on early gastric cancer (EGC) using dual-energy CT (DECT). 31 EGC patients (19 men, 12 women; age range, 38-81 years; mean age, 57.19 years) were retrospectively enrolled in this study. Conventionally reconstructed polyenergetic images (PEIs) at 120 kV and virtual monoenergetic images (MEIs) and AMEIs at six different kiloelectron volt (keV) levels (from 40 to 90 keV) were evaluated from the 100 and Sn 140 kV dual energy image data, respectively. The visibility and stage migration of EGC for all three image data sets were evaluated and statistically analyzed. The objective and subjective image qualities were also evaluated. AMEIs at 40 keV showed the best visibility (80.7 %) and the lowest stage migration (35.5 %) for EGC. The stage migration for AMEIs at 40 keV was significantly lower than that for PEIs (p = 0.026). AMEIs at 40 keV had statistically higher CNR in the arterial and portal phases, gastric-specific diagnostic performance and visual sharpness compared with other AMEIs, MEIs and PEIs (all p < 0.05). AMEIs at 40 keV with MPR increase the CNR of EGC and thus potentially lower the stage migration of EGC. (orig.)

  14. Regularized plane-wave least-squares Kirchhoff migration

    KAUST Repository

    Wang, Xin; Dai, Wei; Schuster, Gerard T.

    2013-01-01

    A Kirchhoff least-squares migration (LSM) is developed in the prestack plane-wave domain to increase the quality of migration images. A regularization term is included that accounts for mispositioning of reflectors due to errors in the velocity

  15. Recent migration developments in the European perspective

    Directory of Open Access Journals (Sweden)

    Milan Palát

    2012-01-01

    Full Text Available The aim of the paper is to evaluate the development of international migration in relationship to the recent economic situation in member countries of the European Union using quantitative methods including cluster analysis. The number of immigration in Europe has declined since the start of the global recession. The main reason was the decrease of demand in many sectors of the national economy, for instance the demand for retail and construction workers. Despite the drop in new immigration, labour markets of the EU countries were hit very severely. Unemployment rates in the most of European countries increased much more in the category of migrants than among natives. Despite the general decline in immigration in Europe during the economic crisis, the number of immigrants employed in educational sector and health care has increased. Also the number of female immigrants has been growing. The cluster analysis uses a multidimensional variable that includes GDP, unemployment, inflation rate and also net migration. We can distinguish two main clusters in 2010. The majority of highly developed West European countries are a part of the first cluster; the second cluster includes the group of post-communist countries. The latter countries form two sub-groups. A relatively independent sub-cluster is formed by some of the EU15 countries that were hit by the financial crisis the most. In general, the main two clusters illustrate that the economic division of established and new member countries of the European Union is still present.

  16. Directional migration in the Hindu castes: inferences from mitochondrial, autosomal and Y-chromosomal data.

    Science.gov (United States)

    Wooding, Stephen; Ostler, Christopher; Prasad, B V Ravi; Watkins, W Scott; Sung, Sandy; Bamshad, Mike; Jorde, Lynn B

    2004-08-01

    Genetic, ethnographic, and historical evidence suggests that the Hindu castes have been highly endogamous for several thousand years and that, when movement between castes does occur, it typically consists of females joining castes of higher social status. However, little is known about migration rates in these populations or the extent to which migration occurs between caste groups of low, middle, and high social status. To investigate these aspects of migration, we analyzed the largest collection of genetic markers collected to date in Hindu caste populations. These data included 45 newly typed autosomal short tandem repeat polymorphisms (STRPs), 411 bp of mitochondrial DNA sequence, and 43 Y-chromosomal single-nucleotide polymorphisms that were assayed in more than 200 individuals of known caste status sampled in Andrah Pradesh, in South India. Application of recently developed likelihood-based analyses to this dataset enabled us to obtain genetically derived estimates of intercaste migration rates. STRPs indicated migration rates of 1-2% per generation between high-, middle-, and low-status caste groups. We also found support for the hypothesis that rates of gene flow differ between maternally and paternally inherited genes. Migration rates were substantially higher in maternally than in paternally inherited markers. In addition, while prevailing patterns of migration involved movement between castes of similar rank, paternally inherited markers in the low-status castes were most likely to move into high-status castes. Our findings support earlier evidence that the caste system has been a significant, long-term source of population structuring in South Indian Hindu populations, and that patterns of migration differ between males and females. Copyright 2004 Springer-Verlag

  17. SiMA: A simplified migration assay for analyzing neutrophil migration.

    Science.gov (United States)

    Weckmann, Markus; Becker, Tim; Nissen, Gyde; Pech, Martin; Kopp, Matthias V

    2017-07-01

    three non-asthmatic patients gives a first hint to the capability of SiMA assay in the context of migration based diagnostics. Using SiMA we were able to identify typical migration profiles of the chemoattractants IL-8, fMLP, and LTB 4 , the effect of the matrices FN versus HEM as well as the response to different medications, that is, Prednisolone induced a change of direction of migrating neutrophils in FN but no such effect was observed in human placental matrix. In addition, neutrophils of asthmatic individuals showed an increased proportion of cells migrating toward the vehicle. With the SiMA platform we presented a simplified but yet flexible platform for cost-effective tracking and quantification of neutrophil migration. The introduced method is based on a simple microscopic video stage, standardized, commercially available, µ-fluidic migration chambers and automated image analysis, and track validation software. © 2017 International Society for Advancement of Cytometry. © 2017 International Society for Advancement of Cytometry.

  18. Bending the urban flow: a construction-migration strategy.

    Science.gov (United States)

    Shaw, R P

    1980-01-01

    The excess rate of migration to urban centers is a problem affecting over 50 developing countries and 18 developed ones (68% of the world's population). Policies that rely on compulsion or disincentives have mostly failed because they do not deal with the cause of the problem. This paper proposes a strategy of increasing or decreasing the rate of housing construction in different urban areas as a means of stimulating or reducing migration to those areas; in most developing areas priority is given to residential construction in already congested metropolitan areas. 5 assumptions are the basis for this approach: 1) migrants tend to gravitate to the most powerful growth poles; 2) residential construction is a leading sector of regional and urban economies; 3) the encouragement of construction activity will make itself felt indirectly via its effect on construction-related employment; 4) rates of residential construction may be manipulated through government policy affecting the cost of materials, availability of loans, level of unionization, and price of housing; and 5) residential construction is amenable to quick policy action. The central idea of the strategy is that an increase in residential construction will exercise a pull on migrants, increasing job opportunities, raising incomes, lowering housing costs, and improving the chances of home ownership. This idea has been verified by various projects in Hong Kong, Ghana, Venezuela, Brazil, Bahrain, Mexico, Colombia, Poland, USSR, and the UK. In Bahrain low-income housing programs have been used to relocate Bahraini nationals in new outlying suburbs and to promote population growth in rural villages. In Mexico self-help and low-income housing programs have helped to redirect migrants headed for small towns toward smaller communities. There is also evidence to show that building construction has the potential to expand and contribute to economic growth. Some problems of implementation might be finding an adequate

  19. A theoretical contribution to the contemporary migration: a socio-philosophical reflection

    Directory of Open Access Journals (Sweden)

    Ana PASCARU

    2016-07-01

    Full Text Available Nowadays we witness an increased use of information & communication technologies (ICT which contributed to important changes in the world due to the Globalization process. Additionally, Globalization and ICT increased the movement of people or the so called migration. The migratory flows have increased considerably in the last decades. Due to this, there is a need to review the migration theories through the lens of the ICT. The analyses of migration and ICT lay the premises for a knowledge-based society. This paper focuses on the migration theories, starting from the dominant and oldest theory explaining the causes of migration. Hereinafter, it discusses the neoclassical theory and the human capital approach, the new economics of migration, network and institutional theory. Thus, there have been many attempts to explain migration from different perspectives but what becomes clear nowadays is that there is still request for more analyses considering updated perspectives.

  20. [Identification and sampling of people with migration background for epidemiological studies in Germany].

    Science.gov (United States)

    Reiss, K; Makarova, N; Spallek, J; Zeeb, H; Razum, O

    2013-06-01

    In 2009, 19.6% of the population of Germany either had migrated themselves or were the offspring of people with migration experience. Migrants differ from the autochthonous German population in terms of health status, health awareness and health behaviour. To further investigate the health situation of migrants in Germany, epidemiological studies are needed. Such studies can employ existing databases which provide detailed information on migration status. Otherwise, onomastic or toponomastic procedures can be applied to identify people with migration background. If migrants have to be recruited into an epidemiological study, this can be done register-based (e. g., data from registration offices or telephone lists), based on residential location (random-route or random-walk procedure), via snowball sampling (e. g., through key persons) or via settings (e. g., school entry examination). An oversampling of people with migration background is not sufficient to avoid systematic bias in the sample due to non-participation. Additional measures have to be taken to increase access and raise participation rates. Personal contacting, multilingual instruments, multilingual interviewers and extensive public relations increase access and willingness to participate. Empirical evidence on 'successful' recruitment strategies for studies with migrants is still lacking in epidemiology and health sciences in Germany. The choice of the recruitment strategy as well as the measures to raise accessibility and willingness to participate depend on the available resources, the research question and the specific migrant target group. © Georg Thieme Verlag KG Stuttgart · New York.

  1. Climate Shocks and Migration: An Agent-Based Modeling Approach

    Science.gov (United States)

    Entwisle, Barbara; Williams, Nathalie E.; Verdery, Ashton M.; Rindfuss, Ronald R.; Walsh, Stephen J.; Malanson, George P.; Mucha, Peter J.; Frizzelle, Brian G.; McDaniel, Philip M.; Yao, Xiaozheng; Heumann, Benjamin W.; Prasartkul, Pramote; Sawangdee, Yothin; Jampaklay, Aree

    2016-01-01

    This is a study of migration responses to climate shocks. We construct an agent-based model that incorporates dynamic linkages between demographic behaviors, such as migration, marriage, and births, and agriculture and land use, which depend on rainfall patterns. The rules and parameterization of our model are empirically derived from qualitative and quantitative analyses of a well-studied demographic field site, Nang Rong district, Northeast Thailand. With this model, we simulate patterns of migration under four weather regimes in a rice economy: 1) a reference, ‘normal’ scenario; 2) seven years of unusually wet weather; 3) seven years of unusually dry weather; and 4) seven years of extremely variable weather. Results show relatively small impacts on migration. Experiments with the model show that existing high migration rates and strong selection factors, which are unaffected by climate change, are likely responsible for the weak migration response. PMID:27594725

  2. Periodic sediment shift in migrating ripples influences benthic microbial activity

    Science.gov (United States)

    Zlatanović, Sanja; Fabian, Jenny; Mendoza-Lera, Clara; Woodward, K. Benjamin; Premke, Katrin; Mutz, Michael

    2017-06-01

    Migrating bedforms have high levels of particulate organic matter and high rates of pore water exchange, causing them to be proposed as hot spots of carbon turnover in rivers. Yet, the shifting of sediments and associated mechanical disturbance within migrating bedforms, such as ripples, may stress and abrade microbial communities, reducing their activity. In a microcosm experiment, we replicated the mechanical disturbances caused by the periodic sediment shift within ripples under oligotrophic conditions. We assessed the effects on fungal and bacterial biomass ratio (F:B), microbial community respiration (CR), and bacterial production (BCP) and compared with stable undisturbed sediments. Interactions between periodic mechanical disturbance and sediment-associated particulate organic matter (POM) were tested by enriching sediments collected from migrating ripples with different qualities of POM (fish feces, leaf litter fragments and no addition treatments). F:B and BCP were affected by an interaction between mechanical disturbance and POM quality. Fish feces enriched sediments showed increased F:B and BCP compared to sediments with lower POM quality and responded with a decrease of F:B and BCP to sediment disturbance. In the other POM treatments F:B and BCP were not affected by disturbance. Microbial respiration was however reduced by mechanical disturbance to similar low activity levels regardless of POM qualities added, whereas fish feces enriched sediment showed short temporary boost of CR. With the worldwide proliferation of migrating sand ripples due to massive catchment erosion, suppressed mineralization of POM will increasingly affect stream metabolism, downstream transport of POM and carbon cycling from reach to catchment scale.

  3. 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.

  4. Overexpression of human sperm protein 17 increases migration and decreases the chemosensitivity of human epithelial ovarian cancer cells

    International Nuclear Information System (INIS)

    Li, Fang-qiu; Han, Yan-ling; Liu, Qun; Wu, Bo; Huang, Wen-bin; Zeng, Su-yun

    2009-01-01

    Most deaths from ovarian cancer are due to metastases that are resistant to conventional therapies. But the factors that regulate the metastatic process and chemoresistance of ovarian cancer are poorly understood. In the current study, we investigated the aberrant expression of human sperm protein 17 (HSp17) in human epithelial ovarian cancer cells and tried to analyze its influences on the cell behaviors like migration and chemoresistance. Immunohistochemistry and immunocytochemistry were used to identify HSp17 in paraffin embedded ovarian malignant tumor specimens and peritoneal metastatic malignant cells. Then we examined the effect of HSp17 overexpression on the proliferation, migration, and chemoresistance of ovarian cancer cells to carboplatin and cisplatin in a human ovarian carcinoma cell line, HO8910. We found that HSp17 was aberrantly expressed in 43% (30/70) of the patients with primary epithelial ovarian carcinomas, and in all of the metastatic cancer cells of ascites from 8 patients. The Sp17 expression was also detected in the metastatic lesions the same as in ovarian lesions. None of the 7 non-epithelial tumors primarily developed in the ovaries was immunopositive for HSp17. Overexpression of HSp17 increased the migration but decreased the chemosensitivity of ovarian carcinoma cells to carboplatin and cisplatin. HSp17 is aberrantly expressed in a significant proportion of epithelial ovarian carcinomas. Our results strongly suggest that HSp17 plays a role in metastatic disease and resistance of epithelial ovarian carcinoma to chemotherapy

  5. The planetesimal-driven migration of planets: Observational consequences

    International Nuclear Information System (INIS)

    Panichi, F.

    2014-01-01

    The role of planetary migration in a non–self-gravity planetesimals disk is analyzed in this paper. I calculate the migration rate exerted on a planet due to the gravitational interaction with a planetesimals disk both numerically and analytically. I use two different configurations for the disk-planet interaction: corotating (with an inclination of 0◦ with respect to the plane of motion of the disk) and counter-rotating (with an inclination of 180◦) planet. I perform 2D numerical simulations of disks with 104 planetesimals with or without a Rayleigh distribution in eccentricity. I show that counter- and co-rotating planets have different migration rates: retrograde planets migrate faster than the prograde ones. The migration rate depends on the ratio between the planet to planetesimal mass and on the initial mean eccentricity of planetesimals. I compare numerical simulations with analytical theories of dynamical friction and linear theory of density waves. In both cases each theory can explain only parts of the simulation results. A more general and powerful analytical theory of planet migration must be realized. Finally I simulate the observation of co- and counter-rotating massless disks of planetesimals with the interferometer ALMA. With the high resolution of ALMA it is possible to characterize the gap created by the resonances overlap. I show that in the two cases different resonance conditions create gaps with different extensions which can be observed with ALMA for a distance of 100 parsec and a disk size of 100 A.U., and for disks of 20 A.U. and a distance of 50 parsec. With this simple method it is possible to calculate the planet’s mass in both cases studying the indirect presence of the planet. The case of massive disks are also investigated. In this case planet migration creates a large modification of the planetesimals density profile that can be studied observing the brightness surface profile of the disk. Conversely to other detection

  6. Mexican experience on migration and development 1990-2013

    Directory of Open Access Journals (Sweden)

    Rodolfo García Zamora

    Full Text Available After 40 years of a long rising emigration from Mexico to the United States, the number of Mexicans increased to 12 million in 2006, while the increased input of remittances reached $26 million dollars in 2007. Yet, the increasing migration and remittances mainly in Zacatecas and Michoacan states do not achieve economic and social development because of the persistent backwardness, unemployment and marginalization. It demands the need for new Policies of Development, Migration and Human Rights that allow exercising the right to not emigrate in a medium term. Positive products of this long migration are the Mexican Migrant Clubs and their Federations that elaborated the concrete development proposals. Whereas, the possibility that these proposals can become a Development, Migration and Human Rights, Comprehensive and Long Term State Policy will depend on the capacity and participation of Mexican Civil Society and the Transnational Communities in both countries.

  7. Modeling of brine migration in halite

    International Nuclear Information System (INIS)

    Cheung, H.; Fuller, M.E.; Gaffney, E.S.

    1979-01-01

    When canisters containing radwastes are emplaced in a repository the heat produced by the decaying radwaste will cause moderate thermal gradients to develop which will cause the brine present in a halite medium (salt deposits) to accumulate around the canister. Four different models of the migration process have been reviewed to determine their suitability as a working model. One model predicts that inclusions smaller than 0.1 mm dimension probably will not migrate. The other models do not consider size as a factor. Thermal diffusion (Soret effect) is considered insignificant in three models, while in the fourth model it is added to the concentration diffusion term. The following conclusions can be made: Temperature is the most significant parameter in all models and must be known as a function of time, and distance from the canister. All four models predict about the same migration velocity for it is a given set of conditions; for 100 0 C and 1 0 C/cm thermal gradient, it is 3.0, 4.8, 5.6 and 6.4 mm/y. Diffusion of ions through the brine inclusions is the rate controlling mechanism. The difference between the thermal gradients in the liquid and in the solid should always be considered and is a function of droplet shape. The model based upon work by Nernst is easiest to use, but it predicts the lowest migration rate. The maximum volume of pure brine accumulated at the canister surface would be less than 20-40 liters in 50 years, for a canister initial thermal power of 3.5 kW.Bitterns would migrate proportionately less volume. A computer code, BRINE, was developed to make these calculations by means of any of the four models

  8. TNFα-mediated loss of β-catenin/E-cadherin association and subsequent increase in cell migration is partially restored by NKX3.1 expression in prostate cells.

    Directory of Open Access Journals (Sweden)

    Bilge Debelec-Butuner

    Full Text Available Inflammation-induced carcinogenesis is associated with increased proliferation and migration/invasion of various types of tumor cells. In this study, altered β-catenin signaling upon TNFα exposure, and relation to loss of function of the tumor suppressor NKX3.1 was examined in prostate cancer cells. We used an in vitro prostate inflammation model to demonstrate altered sub-cellular localization of β-catenin following increased phosphorylation of Akt(S473 and GSK3β(S9. Consistently, we observed that subsequent increase in β-catenin transactivation enhanced c-myc, cyclin D1 and MMP2 expressions. Consequently, it was also observed that the β-catenin-E-cadherin association at the plasma membrane was disrupted during acute cytokine exposure. Additionally, it was demonstrated that disrupting cell-cell interactions led to increased migration of LNCaP cells in real-time migration assay. Nevertheless, ectopic expression of NKX3.1, which is degraded upon proinflammatory cytokine exposure in inflammation, was found to induce the degradation of β-catenin by inhibiting Akt(S473 phosphorylation, therefore, partially rescued the disrupted β-catenin-E-cadherin interaction as well as the cell migration in LNCaP cells upon cytokine exposure. As, the disrupted localization of β-catenin at the cell membrane as well as increased Akt(S308 priming phosphorylation was observed in human prostate tissues with prostatic inflammatory atrophy (PIA, high-grade prostatic intraepithelial neoplasia (H-PIN and carcinoma lesions correlated with loss of NKX3.1 expression. Thus, the data indicate that the β-catenin signaling; consequently sub-cellular localization is deregulated in inflammation, associates with prostatic atrophy and PIN pathology.

  9. Lines of evidence for environmentally driven human migration

    Science.gov (United States)

    Davis, K. F.; D'Odorico, P.

    2012-12-01

    International human migration is an important mechanism that affects, and is affected by, various human and natural systems. With the number of people living outside their countries of origin currently estimated at 214 million people and projected to potentially reach more than 400 million people by mid-century, the topic of international human movements presents possible advantages and pitfalls for both sending and receiving countries on multiple fronts (e.g. economic, environmental, political and cultural). Understanding how human migration interacts with human and natural systems is therefore essential in realizing a sustainable and balanced future. While the study of international migration has historically been motivated largely by economic and political interests, the issue of environmentally induced migration has become increasingly important in light of a rapidly changing climate in conjunction with increasing population pressure on many important resources. Particularly in terms of theoretical and conceptual discussions, environmentally induced human migration has been receiving increased attention in the literature. To date, few studies - many of which focus on internal (intra-national) or regional migration - have attempted to quantify the interactions of human migration and the environment, with little attention paid to the global scale as a result of varying regional factors and lack of sufficient data. Recently available global bilateral migration datasets have been developed that allow for a more comprehensive understanding of human movements between all countries. With these datasets, we seek to elucidate environmental drivers of human migration over the past half-century using a multi-pronged approach. First, using a recently developed universal radiation model, we examine human movements based solely on global population distribution. Next, by comparison of migration movements with selected economic, environmental and human welfare indicators, we

  10. Field-scale colloid migration experiments in a granite fracture

    International Nuclear Information System (INIS)

    Vilks, P.; Frost, L.H.; Bachinski, D.B.

    1997-01-01

    An understanding of particle migration in fractured rock, required to assess the potential for colloid-facilitated transport of radionuclides, can best be evaluated when the results of laboratory experiments are demonstrated in the field. Field-scale migration experiments with silica colloids were carried out at AECL's Underground Research Laboratory (URL), located in southern Manitoba, to develop the methodology for large-scale migration experiments and to determine whether colloid transport is possible over distances up to 17 m. In addition, these experiments were designed to evaluate the effects of flow rate and flow path geometry, and to determine whether colloid tracers could be used to provide additional information on subsurface transport to that provided by conservative tracers alone. The colloid migration studies were carried out as part of AECL's Transport Properties in Highly Fractured Rock Experiment, the objective of which was to develop and demonstrate methods for evaluating the solute transport characteristics of zones of highly fractured rock. The experiments were carried out within fracture zone 2 as two-well recirculating, two-well non-recirculating, and convergent flow tests, using injection rates of 5 and 101 min -1 . Silica colloids with a 20 nm size were used because they are potentially mobile due to their stability, small size and negative surface charge. The shapes of elution profiles for colloids and conservative tracers were similar, demonstrating that colloids can migrate over distances of 17 m. The local region of drawdown towards the URL shaft affected colloid migration and, to a lesser extent, conservative tracer migration within the flow field established by the two-well tracer tests. These results indicate that stable colloids, with sizes as small as 20 nm, have different migration properties from dissolved conservative tracers. (author)

  11. Small flow rate can supply inwardly migrating shortest-period planets

    OpenAIRE

    Taylor, Stuart F.

    2013-01-01

    The number of exoplanets found with periods as short as one day and less was surprising given how fast these planets had been expected to migrate into the star due to the tides raised on the star by planets at such close distances. It has been seen as improbable that we would find planets in such a small final fraction of their lives. The favored solution has been that the tidal dissipation is much weaker than expected, which would mean that the final infall would be a larger fraction of the ...

  12. Determinants of Romanians' Migration within the European Union: Static and Dynamic Panel Gravity Approaches

    Directory of Open Access Journals (Sweden)

    Adriana Ana Maria Davidescu

    2017-08-01

    Full Text Available The 1st of January 2007 marked Romania’s accession to the European Union (EU and represented its 'ticket' to a free access to the common market. This soon evolved into an important trigger for the increased migration flows from Romania towards the more developed western countries, members of the EU. Not only the opportunity of a free movement of persons – emerged with the integration - but also the existing socio-economic disparities between Romania and the more developed western countries in the EU, led to unidirectional migration flows. Using both static and dynamic panel gravity models, we aim to identify the main determinants of Romanians' migration towards 10 EU member states – Czech Republic, Denmark, Italy, Netherlands, Finland, Germany, Norway, Poland, Spain, and Sweden – for the period 2007-2014. Our empirical findings support the results of other studies performed on different economies. The most important pull factor for Romanians' migration is represented by the economic conditions in the destination countries, proxied by the GDP/capita. Other important pull factors fuelling Romanians' migration refer to the unemployment rate, life expectancy, education spending, and population density. A key role is also played by the existing social networks in the destination countries which are proxied in our model by the lagged migration flows

  13. Dispersal and migration

    Directory of Open Access Journals (Sweden)

    Schwarz, C.

    2004-06-01

    philopatric movement of geese using a classic multi–state design. Previous studies of philopaty often rely upon simple return rates —however, good mark–recapture studies do not need to assume equal detection probabilities in space and time. This is likely the most important contribution of multi–state modelling to the study of movement. As with many of these studies, the most pressing problem in the analysis is the explosion in the number of parameters and the need to choose parsimonious modelss to get good precision. Drake and Alisauska demonstrate that model choice still remains an art with a great deal of biological insight being very helpful in the task. There is still plenty of scope for novel methods to study migration. Traditionally, there has been a clear cut distinction between birds being labelled as “migrant” or “resident” on the basis of field observations and qualitative interpretations of patterns of ring–recoveries. However, there are intermediate species where only part of the population migrates (partial migrants or where different components of the population migrate to different extents (differential migrants. Siriwardena, Wernham and Baillie (Siriwardena et al., 2004 develop a novel method that produces a quantitative index of migratory tendency. The method uses distributions of ringing–to–recovery distances to classify individual species’ patterns of movement relative to those of other species. The areas between species’ cumulative distance distributions are used with multi–dimensional scaling to produce a similarity map among species. This map can be used to investigate the factors that affect the migratory strategies that species adopt, such as body size, territoriality and distribution, and in studies of their consequences for demographic parameters such as annual survival and the timing of breeding. The key assumption of the method is the similar recovery effort of species over space and time. It would be interesting to

  14. HPLC detection of loss rate and cell migration of HUVECs in a proanthocyanidin cross-linked recombinant human collagen-peptide (RHC)–chitosan scaffold

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jing; Deng, Aipeng [School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Yang, Yang [Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Gao, Lihu; Xu, Na; Liu, Xin; Hu, Lunxiang; Chen, Junhua [School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Yang, Shulin, E-mail: yshulin@njust.edu.cn [School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China)

    2015-11-01

    Porous scaffolds with appropriate pore structure, biocompatibility, mechanical property and processability play an important role in tissue engineering. In this paper, we fabricated a recombinant human collagen-peptide (RHC)–chitosan scaffold cross-linked by premixing 30% proanthocyanidin (PA) in one-step freeze-drying. To remove the residual acetic acid, optimized 0.2 M phosphate buffer of pH 6.24 with 30% ethanol (PBSE) was selected to neutralize the lyophilized scaffold followed by three times deionized water rinse. Ninhydrin assay was used to characterize the components loss during the fabrication process. To detect the exact RHC loss under optimized neutralization condition, high performance liquid chromatography (HPLC) equipped size exclusion chromatography column was used and the total RHC loss rate through PBSE rinse was 19.5 ± 5.08%. Fourier transform infrared spectroscopy (FT-IR) indicated hydrogen bonding among RHC, chitosan and PA, it also presented a probative but not strong hydrophobic interaction between phenyl rings of polyphenols and pyrrolidine rings of proline in RHC. Further, human umbilical vein endothelial cell (HUVEC) viability analyzed by a scanning electron microscope (SEM) and acridine orange/ethidium bromide (AO/EB) fluorescence staining exhibited that this scaffold could not only promote cell proliferation on scaffold surface but also permit cells migration into the scaffold. qRT-PCR exhibited that the optimized scaffold could stimulate angiogenesis associated genes VEGF and CD31 expression. These characterizations indicated that this scaffold can be considered as an ideal candidate for tissue engineering. - Highlights: • PA cross-linked recombinant human collagen–chitosan scaffold. • Fabrication in one-step lyophilization with neutralization. • HPLC detection of RHC loss rate • HUVEC proliferation and migration in scaffold • Angiogenesis associated gene expressions were increased in scaffold cell culturing.

  15. Migration through soil of organic solutes in an oil-shale process water

    Science.gov (United States)

    Leenheer, J.A.; Stuber, H.A.

    1981-01-01

    The migration through soil of organic solutes in an oil-shale process water (retort water) was studied by using soil columns and analyzing leachates for various organic constituents. Retort water extracted significant quantities of organic anions leached from ammonium-saturated-soil organic matter, and a distilled-water rinse, which followed retort-water leaching, released additional organic acids from the soil. After being corrected for organic constitutents extracted from soil by retort water, dissolved-organic-carbon fractionation analyses of effluent fractions showed that the order of increasing affinity of six organic compound classes for the soil was as follows: hydrophilic neutrals nearly equal to hydrophilic acids, followed by the sequence of hydrophobic acids, hydrophilic bases, hydrophobic bases, and hydrophobic neutrals. Liquid-chromatographic analysis of the aromatic amines in the hydrophobic- and hydrophilic-base fractions showed that the relative order of the rates of migration through the soil column was the same as the order of migration on a reversed-phase, octadecylsilica liquid-chromatographic column.

  16. Decoupled deblurring filter and its application to elastic migration and inversion

    KAUST Repository

    Feng, Zongcai

    2017-08-17

    We present a decoupled deblurring filter that approximates the multiparameter Hessian inverse by using local filters to approximate its submatrices for the same and different parameter classes. Numerical tests show that the filter not only reduces the footprint noise, balances the amplitudes and increases the resolution of the elastic migration images, but also mitigates the crosstalk artifacts. When used as a preconditioner, it accelerates the convergence rate for elastic inversion.

  17. Families, children, migration and AIDS.

    Science.gov (United States)

    Haour-Knipe, Mary

    2009-01-01

    Migration is very often a family affair, and often involves children, directly or indirectly. It may give rise to better quality of life for an entire family, or to bitter disappointment, and may also increase vulnerability to HIV and AIDS. This review, carried out for the Joint Learning Initiative on Children and AIDS, links the literature on "migration", on "HIV and AIDS" and on "families". Three themes are sketched: (1) As both HIV prevalence and circular migration increase, former migrant workers affected by AIDS may return to their families for care and support, especially at the end of life, often under crisis conditions. Families thus lose promising members, as well as sources of support. However, very little is known about the children of such migrants. (2) Following patterns of migration established for far different reasons, children may have to relocate to different places, sometimes over long distances, if their AIDS-affected parents can no longer care for them. They face the same adaptation challenges as other children who move, but complicated by loss of parent(s), AIDS stigma, and often poverty. (3) The issue of migrant families living with HIV has been studied to some extent, but mainly in developed countries with a long history of migration, and with little attention paid to the children in such families. Difficulties include involuntary separation from family members, isolation and lack of support, disclosure and planning for children's care should the parent(s) die and differences in treatment access within the same family. Numerous research and policy gaps are defined regarding the three themes, and a call is made for thinking about migration, families and AIDS to go beyond description to include resilience theory, and to go beyond prevention to include care.

  18. 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...

  19. Quantifying stretching and rearrangement in epithelial sheet migration

    International Nuclear Information System (INIS)

    Lee, Rachel M; Nordstrom, Kerstin N; Losert, Wolfgang; Kelley, Douglas H; Ouellette, Nicholas T

    2013-01-01

    Although understanding the collective migration of cells, such as that seen in epithelial sheets, is essential for understanding diseases such as metastatic cancer, this motion is not yet as well characterized as individual cell migration. Here we adapt quantitative metrics used to characterize the flow and deformation of soft matter to contrast different types of motion within a migrating sheet of cells. Using a finite-time Lyapunov exponent (FTLE) analysis, we find that—in spite of large fluctuations—the flow field of an epithelial cell sheet is not chaotic. Stretching of a sheet of cells (i.e. positive FTLE) is localized at the leading edge of migration and increases when the cells are more highly stimulated. By decomposing the motion of the cells into affine and non-affine components using the metric D m in 2 , we quantify local plastic rearrangements and describe the motion of a group of cells in a novel way. We find an increase in plastic rearrangements with increasing cell densities, whereas inanimate systems tend to exhibit less non-affine rearrangements with increasing density. (paper)

  20. Migration of liquid film and grain boundary in Mo-Ni induced by W diffusion

    International Nuclear Information System (INIS)

    Kang, H.K.; Hackney, S.; Yoon, D.N.

    1988-01-01

    The liquid films and grain boundaries in liquid phase sintered Mo-Ni alloy are observed to migrate during heat-treatment after adding W to the liquid matrix. Behind the migrating boundaries forms Mo-Ni-W solid solution with the W concentration decreasing with the migration distance because of W depletion in the liquid matrix. The migration rate during the heat-treatment at 1540 0 C after adding W decreases with the decreasing pretreatment sintering temperature. When the sintering temperature is 1420 0 C, the migration rate is almost reduced to O. Under this condition, the coherency strain due to the simultaneous diffusion of W and Ni into the grain surfaces is estimated to be almost O. The results thus show that the coherency strain due to lattice diffusion is the driving force for the liquid film and grain boundary migration

  1. Waste migration in shallow burial sites under unsaturated flow conditions

    International Nuclear Information System (INIS)

    Eicholz, G.G.; Whang, J.

    1987-01-01

    Unsaturated conditions prevail in many shallow-land burial sites, both in arid and humid regions. Unless a burial site is allowed to flood and possibly overflow, a realistic assessment of any migration scenario must take into account the conditions of unsaturated flow. These are more difficult to observe and to model, but introduce significant changes into projected rates of waste leaching and waste migration. Column tests have been performed using soils from the Southeastern coastal plain to observe the effects of varying degrees of ''unsaturation'' on the movement of radioactive tracers. The moisture content in the columns was controlled by maintaining various levels of hydrostatic suction on soil columns whose hydrodynamic characteristics had been determined carefully. Tracer tests, employing Cs-137, I-131 and Ba-133 were used to determine migration profiles and to follow their movement down the column for different suction values. A calculational model has been developed for unsaturated flow and seems to match the observations fairly well. It is evident that a full description of migration processes must take into account the reduced migration rates under unsaturated conditions and the hysteresis effects associated with wetting-drying cycles

  2. Animal migration amid shifting patterns of phenology and predation: Lessons from a Yellowstone elk herd

    Science.gov (United States)

    Middleton, Arthur D.; Kauffman, Matthew J.; McWhirter, Douglas E.; Cook, John G.; Cook, Rachel C.; Nelson, Abigail A.; Jimenez, Michael D.; Klaver, Robert W.

    2013-01-01

    Migration is a striking behavioral strategy by which many animals enhance resource acquisition while reducing predation risk. Historically, the demographic benefits of such movements made migration common, but in many taxa the phenomenon is considered globally threatened. Here we describe a long-term decline in the productivity of elk (Cervus elaphus) that migrate through intact wilderness areas to protected summer ranges inside Yellowstone National Park, USA. We attribute this decline to a long-term reduction in the demographic benefits that ungulates typically gain from migration. Among migratory elk, we observed a 21-year, 70% reduction in recruitment and a 4-year, 19% depression in their pregnancy rate largely caused by infrequent reproduction of females that were young or lactating. In contrast, among resident elk, we have recently observed increasing recruitment and a high rate of pregnancy. Landscape-level changes in habitat quality and predation appear to be responsible for the declining productivity of Yellowstone migrants. From 1989 to 2009, migratory elk experienced an increasing rate and shorter duration of green-up coincident with warmer spring–summer temperatures and reduced spring precipitation, also consistent with observations of an unusually severe drought in the region. Migrants are also now exposed to four times as many grizzly bears (Ursus arctos) and wolves (Canis lupus) as resident elk. Both of these restored predators consume migratory elk calves at high rates in the Yellowstone wilderness but are maintained at low densities via lethal management and human disturbance in the year-round habitats of resident elk. Our findings suggest that large-carnivore recovery and drought, operating simultaneously along an elevation gradient, have disproportionately influenced the demography of migratory elk. Many migratory animals travel large geographic distances between their seasonal ranges. Changes in land use and climate that disparately influence

  3. Animal migration amid shifting patterns of phenology and predation: lessons from a Yellowstone elk herd.

    Science.gov (United States)

    Middleton, Arthur D; Kauffman, Matthew J; McWhirter, Douglas E; Cook, John G; Cook, Rachel C; Nelson, Abigail A; Jimenez, Michael D; Klaver, Robert W

    2013-06-01

    Migration is a striking behavioral strategy by which many animals enhance resource acquisition while reducing predation risk. Historically, the demographic benefits of such movements made migration common, but in many taxa the phenomenon is considered globally threatened. Here we describe a long-term decline in the productivity of elk (Cervus elaphus) that migrate through intact wilderness areas to protected summer ranges inside Yellowstone National Park, USA. We attribute this decline to a long-term reduction in the demographic benefits that ungulates typically gain from migration. Among migratory elk, we observed a 21-year, 70% reduction in recruitment and a 4-year, 19% depression in their pregnancy rate largely caused by infrequent reproduction of females that were young or lactating. In contrast, among resident elk, we have recently observed increasing recruitment and a high rate of pregnancy. Landscape-level changes in habitat quality and predation appear to be responsible for the declining productivity of Yellowstone migrants. From 1989 to 2009, migratory elk experienced an increasing rate and shorter duration of green-up coincident with warmer spring-summer temperatures and reduced spring precipitation, also consistent with observations of an unusually severe drought in the region. Migrants are also now exposed to four times as many grizzly bears (Ursus arctos) and wolves (Canis lupus) as resident elk. Both of these restored predators consume migratory elk calves at high rates in the Yellowstone wilderness but are maintained at low densities via lethal management and human disturbance in the year-round habitats of resident elk. Our findings suggest that large-carnivore recovery and drought, operating simultaneously along an elevation gradient, have disproportionately influenced the demography of migratory elk. Many migratory animals travel large geographic distances between their seasonal ranges. Changes in land use and climate that disparately influence

  4. EMMPRIN overexpression in SVZ neural progenitor cells increases their migration towards ischemic cortex.

    Science.gov (United States)

    Kanemitsu, Michiko; Tsupykov, Oleg; Potter, Gaël; Boitard, Michael; Salmon, Patrick; Zgraggen, Eloisa; Gascon, Eduardo; Skibo, Galina; Dayer, Alexandre G; Kiss, Jozsef Z

    2017-11-01

    Stimulation of endogenous neurogenesis and recruitment of neural progenitors from the subventricular zone (SVZ) neurogenic site may represent a useful strategy to improve regeneration in the ischemic cortex. Here, we tested whether transgenic overexpression of extracellular matrix metalloproteinase inducer (EMMPRIN), the regulator of matrix metalloproteinases (MMPs) expression, in endogenous neural progenitor cells (NPCs) in the subventricular zone (SVZ) could increase migration towards ischemic injury. For this purpose, we applied a lentivector-mediated gene transfer system. We found that EMMPRIN-transduced progenitors exhibited enhanced MMP-2 activity in vitro and showed improved motility in 3D collagen gel as well as in cortical slices. Using a rat model of neonatal ischemia, we showed that EMMPRIN overexpressing SVZ cells invade the injured cortical tissue more efficiently than controls. Our results suggest that EMMPRIN overexpression could be suitable approach to improve capacities of endogenous or transplanted progenitors to invade the injured cortex. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Increased strength of concrete subject to high loading rates

    International Nuclear Information System (INIS)

    Curbach, M.

    1987-01-01

    Within the scope of this work various problems are discussed which occur in connection with concrete under high tensile loading rates (e.g. when a plane crashes on a nuclear power plant very high loads occur which act only for a very short time). Particularly the causes for the already frequently noticed increases in strength with increasing loading rates are investigated and also the question whether this increased strength can be taken into account when dimensioning a construction. (MM) [de

  6. Reduced rearing density increases postrelease migration success of Atlantic salmon (Salmo salar) smolts

    DEFF Research Database (Denmark)

    Larsen, Martin Hage; Johnsson, Jörgen I; Näslund, Joacim

    2016-01-01

    during rearing in the hatchery. However, individuals reared at reduced density had less eroded dorsal fins and opercula relative to those from the high-density treatment. In the stream, the downstream migration success was 16% higher for fish reared at reduced density than for conspecifics kept at high-density......The overall aim of this study was to investigate the effect of rearing density on the post-release survival of Atlantic salmon (Salmo salar) smolts during seaward migration. Fish were either reared at conventional hatchery density or at one-third of conventional density. Three hundred one-year old...... smolts from each density treatment were individually tagged with passive integrated transponder (PIT) tags and released 3.2 km upstream of a stationary antenna array in a natural stream. There were no significant differences in length, body mass, or condition between fish from the two density treatments...

  7. The benefits and caveats of international nurse migration

    Directory of Open Access Journals (Sweden)

    Hongyan Li

    2014-09-01

    Full Text Available Worldwide, there is a dramatic shortage of nurses. An increase in the migration of nurses from their home countries to recipient countries is having a global effect on the healthcare system. This global phenomenon stems from historical, economical, social, and political factors. Migration has a significant impact on both the individual and national level. This article summarizes the factors that contribute to nurse migration form the perspective of the source and recipient countries. Additionally, the impacts and issues surrounding nurse migration were also analyzed.

  8. The Spatial Structure of Planform Migration - Curvature Relation of Meandering Rivers

    Science.gov (United States)

    Guneralp, I.; Rhoads, B. L.

    2005-12-01

    Planform dynamics of meandering rivers have been of fundamental interest to fluvial geomorphologists and engineers because of the intriguing complexity of these dynamics, the role of planform change in floodplain development and landscape evolution, and the economic and social consequences of bank erosion and channel migration. Improved understanding of the complex spatial structure of planform change and capacity to predict these changes are important for effective stream management, engineering and restoration. The planform characteristics of a meandering river channel are integral to its planform dynamics. Active meandering rivers continually change their positions and shapes as a consequence of hydraulic forces exerted on the channel banks and bed, but as the banks and bed change through sediment transport, so do the hydraulic forces. Thus far, this complex feedback between form and process is incompletely understood, despite the fact that the characteristics and the dynamics of meandering rivers have been studied extensively. Current theoretical models aimed at predicting planform dynamics relate rates of meander migration to local and upstream planform curvature where weighting of the influence of curvature on migration rate decays exponentially over distance. This theoretical relation, however, has not been rigorously evaluated empirically. Furthermore, although models based on exponential-weighting of curvature effects yield fairly realistic predictions of meander migration, such models are incapable of reproducing complex forms of bend development, such as double heading or compound looping. This study presents the development of a new methodology based on parametric cubic spline interpolation for the characterization of channel planform and the planform curvature of meandering rivers. The use of continuous mathematical functions overcomes the reliance on bend-averaged values or piece-wise discrete approximations of planform curvature - a major limitation

  9. Climate Variability and Migration: Evidence from Tanzania

    OpenAIRE

    Mathilde MAUREL; Zaneta KUBIK

    2014-01-01

    We analyze whether Tanzanian households engage in internal migration as a response to weather-related shocks. Our findings confirm that climate shocks lead to a higher probability of migration by reducing agricultural yields, which in turn induces households to send their members away in order to spatially diversify their income. This effect is, however, low, since a 1% reduction in agricultural income induced by weather shock increases the probability of migration by 3% for an average househ...

  10. Intrauterine Devices Penetrated and Migrated: CT Findings

    International Nuclear Information System (INIS)

    Mejia Restrepo, Jorge; Lopez, Juan Esteban; Aldana Sepulveda, Natalia; Ruiz Zabaleta, Tania; Mazzaro Mauricio

    2011-01-01

    Intrauterine devices have been used for over 40 years, and they constitute the most widely accepted method of contraception among women because of the low rates of complications and low cost. Although uncommon, with the growing use of multidetector CT penetrated and migrated intrauterine devices have become a more common incidental finding. In some cases, intrauterine devices migrate to adjacent viscera, in particular the bladder and bowel and may give rise to symptoms. Consequently tomographic localization and characterization are essential for treatment planning.

  11. DRG migration: A novel measure of inefficient surgical care in a value-based world.

    Science.gov (United States)

    Hughes, Byron D; Mehta, Hemalkumar B; Sieloff, Eric; Shan, Yong; Senagore, Anthony J

    2018-03-01

    Diagnosis-Related Group (DRG) migration, DRG 331 to 330, is defined by the assignment to a higher cost DRG due only to post admission comorbidity or complications (CC). We assessed the 5% national Medicare data set (2011-2014) for colectomy (DRG's 331/330), excluding present on admission CC's and selecting patients with one or more CC's post-admission to define the impact on payments, cost, and length of stay (LOS). The incidence of DRG migration was 14.2%. This was associated with statistically significant increases in payments, hospital cost, and LOS compared to DRG 331 patients. When DRG migration rate was extrapolated to the entire at risk population, the results were an increase of Centers for Medicare and Medicaid Services (CMS) cost by $98 million, hospital cost by $418 million, and excess hospital days equaling 68,669 days. These negative outcomes represent potentially unnecessary variations in the processes of care, and therefore a unique economic concept defining inefficient surgical care. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. [Characteristics of migration in the population of Yevpatoria (Crimea)].

    Science.gov (United States)

    Atramentova, L A; Meshcheriakova, I P; Filiptsova, O V

    2014-09-01

    Indicators characterizing population migration were calculated according to the marriage records of Yevpatoria (Crimea) of 1960/1961, 1985, and 1994/1995. The marital migration coefficient m in those years was 0.80, 0.75, and 0.66, the endogamy index was 0.04, 0.08, and 0.15, and the rate of marriage contingency by birthplace was 0.15, 0.16, and 0.19, respectively. The highest values of the positive mating assortative index were recorded for people from the Caucasus, Central, Central Black Earth Oblast, and Northwest regions of Russia in 1960/1961 and for migrants from Moldavia, the republics of Central Asia and Caucasus, Western Siberia, and Ukraine in 1985. In 1994/1995, natives of Yevpatoria were also included in this group. The average distance of migration by year was 909, 1280, and 1314 km, and the marital distance was 960, 1397, and 1171 km. The "radius" of the Yevpatoria population, in accordance with the Maleco model in the years under study, was 98, 134, and 137 km. The distance isolation indicator b was decreasing and amounted to 0.00049, 0.00043, and 0.00038. Inthe migration flow in all of the periods, the majority of immigrants came from different regions of Ukraine outside Crimea (27-31%), followed by natives of various places in Crimea (21-24%.), Central (3.6-8.5%), and Central Black Earth (1.8-6.1%) regions of Russia, and the South Caucasus (4.0-5.7%). The proportion of Russians and Jews decreased in the migration flow, while the proportion of Ukrainians and representatives of non-Slavic nationalities increased.

  13. Bedform migration in steep channels: from local avalanches to large scale changes

    Science.gov (United States)

    Mettra, F.; Heyman, J.; Ancey, C.

    2013-12-01

    Many studies have emphasized the strength of bedload transport fluctuations in steep streams, especially at low and intermediate transport conditions (relative to the threshold of incipient motion). The origins of these fluctuations, which appear on a wide range of time scales, are still not well understood. In this study, we present the data obtained from a 2D idealized laboratory experiment with the objective of simultaneously recording the channel bed evolution and bedload transport rate at a high temporal resolution. A 3-m long by 8-cm wide transparent flume filled with well-sorted natural gravel (d50=6.5 mm) was used. An efficient technique using accelerometers has been developed to record the arrival time of every particle at the outlet of the flume for long experimental durations (up to a few days). In addition, bed elevation was monitored using cameras filming from the side of the channel, allowing the observation of global aggradation/degradation as well as bedform migration. The experimental parameters were the water discharge, the flume inclination (from 2° to 5°) and the constant feeding rate of sediments. Large-scale bed evolution showed successive aggradation and rapid degradation periods. Indeed, the measured global channel slope, i.e. mean slope over the flume length, fluctuated continuously within a range sometimes wider than 1° (experimental parameters were constant over the entire run). The analysis of these fluctuations provides evidence that steep channels behave like metastable systems, similarly to grain piles. The metastable effects increased for steeper channels and lower transport conditions. In this measurement campaign, we mainly observed upstream-migrating antidunes. For each run, various antidune heights and celerities were measured. On average, the mean antidune migration rate increased with decreasing channel slope and increasing sediment feeding rate. Relatively rare tall and fast-moving antidunes appeared more frequently at high

  14. Widespread increase of tree mortality rates in the Western United States

    Science.gov (United States)

    van Mantgem, P.J.; Stephenson, N.L.; Byrne, J.C.; Daniels, L.D.; Franklin, J.F.; Fule, P.Z.; Harmon, M.E.; Larson, A.J.; Smith, Joseph M.; Taylor, A.H.; Veblen, T.T.

    2009-01-01

    Persistent changes in tree mortality rates can alter forest structure, composition, and ecosystem services such as carbon sequestration. Our analyses of longitudinal data from unmanaged old forests in the western United States showed that background (noncatastrophic) mortality rates have increased rapidly in recent decades, with doubling periods ranging from 17 to 29 years among regions. Increases were also pervasive across elevations, tree sizes, dominant genera, and past fire histories. Forest density and basal area declined slightly, which suggests that increasing mortality was not caused by endogenous increases in competition. Because mortality increased in small trees, the overall increase in mortality rates cannot be attributed solely to aging of large trees. Regional warming and consequent increases in water deficits are likely contributors to the increases in tree mortality rates.

  15. Male out-migration: a factor for the spread of HIV infection among married men and women in rural India.

    Directory of Open Access Journals (Sweden)

    Niranjan Saggurti

    Full Text Available INTRODUCTION: Thus far, the reasons for increasing HIV prevalence in northern and eastern Indian states are unknown. We investigated the role of male out-migration in the spread of human immunodeficiency virus (HIV infection through a case-control study in rural India. METHODS: Currently married men and women were recruited from HIV testing and treatment centers across seven selected districts with high rates of male out-migration in eastern and northern India in 2010 using a case-control study design. Case subjects (men: 595, women: 609 were people who tested HIV seropositive and control subjects (men: 611, women: 600 were those tested HIV seronegative. For each gender, we obtained adjusted odds ratios (AORs and population attributable risks (PARs for migration, and behavioral factors. RESULTS: For men, the prevalence of HIV was significantly higher among those with a migration history (AOR, 4.4; for women, the prevalence of HIV was higher among those with migrant husbands (AOR, 2·3. For both genders, the returned male migration (men: AOR, 3·7; women: AOR, 28 was significantly associated with higher prevalence of HIV infection. The PAR associated with male migration was higher for men (54.5%-68.6% than for women (32·7%-56·9% across the study areas. DISCUSSION: Male out-migration is the most important risk factor influencing the spread of HIV infection in rural areas with high out-migration rates, thereby emphasizing the need for interventions, particularly, for returned migrants and spouses of those migrants.

  16. 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

  17. Lutein Inhibits the Migration of Retinal Pigment Epithelial Cells via Cytosolic and Mitochondrial Akt Pathways (Lutein Inhibits RPE Cells Migration

    Directory of Open Access Journals (Sweden)

    Ching-Chieh Su

    2014-08-01

    Full Text Available During the course of proliferative vitreoretinopathy (PVR, the retinal pigment epithelium (RPE cells will de-differentiate, proliferate, and migrate onto the surfaces of the sensory retina. Several studies have shown that platelet-derived growth factor (PDGF can induce migration of RPE cells via an Akt-related pathway. In this study, the effect of lutein on PDGF-BB-induced RPE cells migration was examined using transwell migration assays and Western blot analyses. We found that both phosphorylation of Akt and mitochondrial translocation of Akt in RPE cells induced by PDGF-BB stimulation were suppressed by lutein. Furthermore, the increased migration observed in RPE cells with overexpressed mitochondrial Akt could also be suppressed by lutein. Our results demonstrate that lutein can inhibit PDGF-BB induced RPE cells migration through the inhibition of both cytoplasmic and mitochondrial Akt activation.

  18. 137Cs content in the ration of rural population of regions with increased nuclide migration

    International Nuclear Information System (INIS)

    Marej, A.N.

    1980-01-01

    Considered is the ration of rural population of arctic regions and Byelorussian-Ukrainian woodlands. The peculiarity of the nitrition structure of the population in the North is a relatively large contribution of deer meat in the ration. The main amount of 137 Cs contribution with other food stuffs and drinking water in the ration of population of this area does not exceed 10 %. The main supplier of 137 Cs in the ration of population of woodlands is milk which constitutes 70 %. The second place is taken by potatoes. The role and significance of separate food stuffs as 137 Cs suppliers in the ration in the zones with increased migration can be different; the leading role in this process is played by natural factors

  19. Couple Relationship Standards and Migration: Comparing Hong Kong Chinese with Australian Chinese.

    Science.gov (United States)

    Halford, W Kim; Leung, Patrick; Hung-Cheung, Chan; Chau-Wan, Lau; Hiew, Danika; van de Vijver, Fons J R

    2017-12-14

    Rates of international migration are increasing, which raises the question of how migration might influence couple relationship standards and impact on the standards of migrants forming intercultural relationships. We compared relationship standards in n = 286 Chinese living in Hong Kong, China, with standards in n = 401 Chinese migrants to a Western country (Australia) by administering the Chinese-Western Intercultural Couple Standards Scale (CWICSS). We also compared these two groups to n = 312 Westerners living in Australia. We first tested the structural invariance of the CWICSS across the three samples with a multigroup confirmatory factor analysis. There was marginal but acceptable fit of a model of two positively correlated latent factors: Couple Bond (with four indicators, such as demonstration of love and caring) and Family Responsibility (also with four indicators, such as extended family relations and preserving face). Within the limitations of the study, results suggest migration is associated predominantly with differences in women's, but not men's, relationship standards. Migrant Chinese women show alignment of Couple Bond standards with Western standards, and divergence of Family Responsibility standards from Western standards. Discussion focused on how migration and intercultural relationship experiences might differentially influence various domains of relationship standards, gender differences in migration effects on standards, and the implications for working with culturally diverse couples. © 2017 Family Process Institute.

  20. 3D plane-wave least-squares Kirchhoff migration

    KAUST Repository

    Wang, Xin; Dai, Wei; Huang, Yunsong; Schuster, Gerard T.

    2014-01-01

    A three dimensional least-squares Kirchhoff migration (LSM) is developed in the prestack plane-wave domain to increase the quality of migration images and the computational efficiency. Due to the limitation of current 3D marine acquisition

  1. Light pollution is greatest within migration passage areas for nocturnally-migrating birds around the world.

    Science.gov (United States)

    Cabrera-Cruz, Sergio A; Smolinsky, Jaclyn A; Buler, Jeffrey J

    2018-02-19

    Excessive or misdirected artificial light at night (ALAN) produces light pollution that influences several aspects of the biology and ecology of birds, including disruption of circadian rhythms and disorientation during flight. Many migrating birds traverse large expanses of land twice every year at night when ALAN illuminates the sky. Considering the extensive and increasing encroachment of light pollution around the world, we evaluated the association of the annual mean ALAN intensity over land within the geographic ranges of 298 nocturnally migrating bird species with five factors: phase of annual cycle, mean distance between breeding and non-breeding ranges, range size, global hemisphere of range, and IUCN category of conservation concern. Light pollution within geographic ranges was relatively greater during the migration season, for shorter-distance migrants, for species with smaller ranges, and for species in the western hemisphere. Our results suggest that migratory birds may be subject to the effects of light pollution particularly during migration, the most critical stage in their annual cycle. We hope these results will spur further research on how light pollution affects not only migrating birds, but also other highly mobile animals throughout their annual cycle.

  2. Nogo-B regulates migration and contraction of airway smooth muscle cells by decreasing ARPC 2/3 and increasing MYL-9 expression

    Directory of Open Access Journals (Sweden)

    Cai Zailong

    2011-01-01

    Full Text Available Abstract Background Abnormal proliferation, apoptosis, migration and contraction of airway smooth muscle (ASM cells in airway remodeling in asthma are basically excessive repair responses to a network of inflammatory mediators such as PDGF, but the mechanisms of such responses remain unclear. Nogo-B, a member of the reticulum family 4(RTN4, is known to play a key role in arteriogenesis and tissue repair. Further studies are needed to elucidate the role of Nogo-B in airway smooth muscle abnormalities. Methods A mouse model of chronic asthma was established by repeated OVA inhalation and subjected to Nogo-B expression analysis using immunohistochemistry and Western Blotting. Then, primary human bronchial smooth muscle cells (HBSMCs were cultured in vitro and a siRNA interference was performed to knockdown the expression of Nogo-B in the cells. The effects of Nogo-B inhibition on PDGF-induced HBSMCs proliferation, migration and contraction were evaluated. Finally, a proteomic analysis was conducted to unveil the underlying mechanisms responsible for the function of Nogo-B. Results Total Nogo-B expression was approximately 3.08-fold lower in chronic asthmatic mice compared to naïve mice, which was obvious in the smooth muscle layer of the airways. Interference of Nogo-B expression by siRNA resulted nearly 96% reduction in mRNA in cultured HBSMCs. In addition, knockdown of Nogo-B using specific siRNA significantly decreased PDGF-induced migration of HBSMCs by 2.3-fold, and increased the cellular contraction by 16% compared to negative controls, but had limited effects on PDGF-induced proliferation. Furthermore, using proteomic analysis, we demonstrate that the expression of actin related protein 2/3 complex subunit 5 (ARPC 2/3 decreased and, myosin regulatory light chain 9 isoform a (MYL-9 increased after Nogo-B knockdown. Conclusions These data define a novel role for Nogo-B in airway remodeling in chronic asthma. Endogenous Nogo-B, which may exert

  3. Hydrology/Radionuclide Migration Program and related research activities

    International Nuclear Information System (INIS)

    Jones, M.A.

    1992-02-01

    This report presents the results of technical studies conducted under the Hydrology/Radionuclide Migration Program (HRMP) at the Nevada Test Site (NTS) for the period of October 1, 1985 through September 30, 1986. The HRMP was initiated in 1973 as the Radionuclide Migration Program to study and better understand the hydrologic systems of the NTS and potential movement and rates of movement of radionuclides and other contaminants injected into these systems by underground nuclear testing

  4. MIGRATIONS OF RELEASED SEISMIC ENERGY IN VARIOUS GEODYNAMIC CONDITIONS

    Directory of Open Access Journals (Sweden)

    A. V. Novopashina

    2018-01-01

    Full Text Available The properties of slow seismic activity migration have been revealed by the space-time analysis of the total earthquake energy (LgEsum. Our study of seismic activity covers the fragments of  the Central Asian, Pacific and Alpine seismic belts: the Baikal rift system (BRS, Russia, the San Andreas fault zone (California, USA, the Christchurch fault (New Zealand, the North and East Anatolian faults (Turkey, the Philippine subduction zone, and the central fragment of the Mid-Atlantic oceanic ridge. The chains of LgEsum clusters mark the propagation of the maximum stresses front in the weaker crust areas, the zones of fault dynamic influence, and the regions of conjugated tectonic structures. The migration process is characterized by a periodicity, changes in direction, and similar modular values of the migration rates within a single fault segment (or a fault zone, which is probably related to the mechanical and rheological crust and upper mantle properties. The data analysis shows that a strong earthquake source may occur at a location wherein the front of seismic activity propagates with periodical changes in direction, and such a source can develop within a period that is multiple of the migration fluctuations, probably associated with the influence of external periodic factors. The main periods of migration fluctuations (2–4 years, and 9–13 years, in different ratios are present in the seismic regimes of different seismic belts. The migration rate, as well as the propagation velocity of the maximum stresses front, directly depends on the velocity of movements between the plates in the region.

  5. Spontaneous neutrophil migration patterns during sepsis after major burns.

    Science.gov (United States)

    Jones, Caroline N; Moore, Molly; Dimisko, Laurie; Alexander, Andrew; Ibrahim, Amir; Hassell, Bryan A; Warren, H Shaw; Tompkins, Ronald G; Fagan, Shawn P; Irimia, Daniel

    2014-01-01

    Finely tuned to respond quickly to infections, neutrophils have amazing abilities to migrate fast and efficiently towards sites of infection and inflammation. Although neutrophils ability to migrate is perturbed in patients after major burns, no correlations have yet been demonstrated between altered migration and higher rate of infections and sepsis in these patients when compared to healthy individuals. To probe if such correlations exist, we designed microfluidic devices to quantify the neutrophil migration phenotype with high precision. Inside these devices, moving neutrophils are confined in channels smaller than the neutrophils and forced to make directional decisions at bifurcations and around posts. We employed these devices to quantify neutrophil migration across 18 independent parameters in 74 blood samples from 13 patients with major burns and 3 healthy subjects. Blinded, retrospective analysis of clinical data and neutrophil migration parameters revealed that neutrophils isolated from blood samples collected during sepsis migrate spontaneously inside the microfluidic channels. The spontaneous neutrophil migration is a unique phenotype, typical for patients with major burns during sepsis and often observed one or two days before the diagnosis of sepsis is confirmed. The spontaneous neutrophil migration phenotype is rare in patients with major burns in the absence of sepsis, and is not encountered in healthy individuals. Our findings warrant further studies of neutrophils and their utility for early diagnosing and monitoring sepsis in patients after major burns.

  6. Migration of northern yellowstone elk: Implications of spatial structuring

    Science.gov (United States)

    White, P.J.; Proffitt, K.M.; Mech, L.D.; Evans, S.B.; Cunningham, J.A.; Hamlin, K.L.

    2010-01-01

    Migration can enhance survival and recruitment of mammals by increasing access to higher-quality forage or reducing predation risk, or both. We used telemetry locations collected from 140 adult female elk during 20002003 and 20072008 to identify factors influencing the migration of northern Yellowstone elk. Elk wintered in 2 semidistinct herd segments and migrated 10140 km to at least 12 summer areas in Yellowstone National Park (YNP) and nearby areas of Montana. Spring migrations were delayed after winters with increased snow pack, with earlier migration in years with earlier vegetation green-up. Elk wintering at lower elevations outside YNP migrated an average of 13 days earlier than elk at higher elevations. The timing of autumn migrations varied annually, but elk left their summer ranges at about the same time regardless of elevation, wolf numbers, or distance to their wintering areas. Elk monitored for multiple years typically returned to the same summer (96 fidelity, n 52) and winter (61 fidelity, n 41) ranges. Elk that wintered at lower elevations in or near the northwestern portion of the park tended to summer in the western part of YNP (56), and elk that wintered at higher elevations spent summer primarily in the eastern and northern parts of the park (82). Elk did not grossly modify their migration timing, routes, or use areas after wolf restoration. Elk mortality was low during summer and migration (8 of 225 elk-summers). However, spatial segregation and differential mortality and recruitment between herd segments on the northern winter range apparently contributed to a higher proportion of the elk population wintering outside the northwestern portion of YNP and summering in the western portion of the park. This change could shift wolf spatial dynamics more outside YNP and increase the risk of transmission of brucellosis from elk to cattle north of the park. ?? 2010 American Society of Mammalogists.

  7. Photon-induced cell migration and integrin expression promoted by DNA integration of HPV16 genome

    International Nuclear Information System (INIS)

    Rieken, Stefan; Simon, Florian; Habermehl, Daniel; Dittmar, Jan Oliver; Combs, Stephanie E.; Weber, Klaus; Debus, Juergen; Lindel, Katja

    2014-01-01

    Persistent human papilloma virus 16 (HPV16) infections are a major cause of cervical cancer. The integration of the viral DNA into the host genome causes E2 gene disruption which prevents apoptosis and increases host cell motility. In cervical cancer patients, survival is limited by local infiltration and systemic dissemination. Surgical control rates are poor in cases of parametrial infiltration. In these patients, radiotherapy (RT) is administered to enhance local control. However, photon irradiation itself has been reported to increase cell motility. In cases of E2-disrupted cervical cancers, this phenomenon would impose an additional risk of enhanced tumor cell motility. Here, we analyze mechanisms underlying photon-increased migration in keratinocytes with differential E2 gene status. Isogenic W12 (intact E2 gene status) and S12 (disrupted E2 gene status) keratinocytes were analyzed in fibronectin-based and serum-stimulated migration experiments following single photon doses of 0, 2, and 10 Gy. Quantitative FACS analyses of integrin expression were performed. Migration and adhesion are increased in E2 gene-disrupted keratinocytes. E2 gene disruption promotes attractability by serum components, therefore, effectuating the risk of local infiltration and systemic dissemination. In S12 cells, migration is further increased by photon RT which leads to enhanced expression of fibronectin receptor integrins. HPV16-associated E2 gene disruption is a main predictor of treatment-refractory cancer virulence. E2 gene disruption promotes cell motility. Following photon RT, E2-disrupted tumors bear the risk of integrin-related infiltration and dissemination. (orig.) [de

  8. Multi-source least-squares reverse time migration

    KAUST Repository

    Dai, Wei

    2012-06-15

    Least-squares migration has been shown to improve image quality compared to the conventional migration method, but its computational cost is often too high to be practical. In this paper, we develop two numerical schemes to implement least-squares migration with the reverse time migration method and the blended source processing technique to increase computation efficiency. By iterative migration of supergathers, which consist in a sum of many phase-encoded shots, the image quality is enhanced and the crosstalk noise associated with the encoded shots is reduced. Numerical tests on 2D HESS VTI data show that the multisource least-squares reverse time migration (LSRTM) algorithm suppresses migration artefacts, balances the amplitudes, improves image resolution and reduces crosstalk noise associated with the blended shot gathers. For this example, the multisource LSRTM is about three times faster than the conventional RTM method. For the 3D example of the SEG/EAGE salt model, with a comparable computational cost, multisource LSRTM produces images with more accurate amplitudes, better spatial resolution and fewer migration artefacts compared to conventional RTM. The empirical results suggest that multisource LSRTM can produce more accurate reflectivity images than conventional RTM does with a similar or less computational cost. The caveat is that the LSRTM image is sensitive to large errors in the migration velocity model. © 2012 European Association of Geoscientists & Engineers.

  9. Multi-source least-squares reverse time migration

    KAUST Repository

    Dai, Wei; Fowler, Paul J.; Schuster, Gerard T.

    2012-01-01

    Least-squares migration has been shown to improve image quality compared to the conventional migration method, but its computational cost is often too high to be practical. In this paper, we develop two numerical schemes to implement least-squares migration with the reverse time migration method and the blended source processing technique to increase computation efficiency. By iterative migration of supergathers, which consist in a sum of many phase-encoded shots, the image quality is enhanced and the crosstalk noise associated with the encoded shots is reduced. Numerical tests on 2D HESS VTI data show that the multisource least-squares reverse time migration (LSRTM) algorithm suppresses migration artefacts, balances the amplitudes, improves image resolution and reduces crosstalk noise associated with the blended shot gathers. For this example, the multisource LSRTM is about three times faster than the conventional RTM method. For the 3D example of the SEG/EAGE salt model, with a comparable computational cost, multisource LSRTM produces images with more accurate amplitudes, better spatial resolution and fewer migration artefacts compared to conventional RTM. The empirical results suggest that multisource LSRTM can produce more accurate reflectivity images than conventional RTM does with a similar or less computational cost. The caveat is that the LSRTM image is sensitive to large errors in the migration velocity model. © 2012 European Association of Geoscientists & Engineers.

  10. Genetic modification of mesenchymal stem cells overexpressing CCR1 increases cell viability, migration, engraftment, and capillary density in the injured myocardium.

    Science.gov (United States)

    Huang, Jing; Zhang, Zhiping; Guo, Jian; Ni, Aiguo; Deb, Arjun; Zhang, Lunan; Mirotsou, Maria; Pratt, Richard E; Dzau, Victor J

    2010-06-11

    Although mesenchymal stem cell (MSC) transplantation has been shown to promote cardiac repair in acute myocardial injury in vivo, its overall restorative capacity appears to be restricted mainly because of poor cell viability and low engraftment in the ischemic myocardium. Specific chemokines are upregulated in the infarcted myocardium. However the expression levels of the corresponding chemokine receptors (eg, CCR1, CXCR2) in MSCs are very low. We hypothesized that this discordance may account for the poor MSC engraftment and survival. To determine whether overexpression of CCR1 or CXCR2 chemokine receptors in MSCs augments their cell survival, migration and engraftment after injection in the infarcted myocardium. Overexpression of CCR1, but not CXCR2, dramatically increased chemokine-induced murine MSC migration and protected MSC from apoptosis in vitro. Moreover, when MSCs were injected intramyocardially one hour after coronary artery ligation, CCR1-MSCs accumulated in the infarcted myocardium at significantly higher levels than control-MSCs or CXCR2-MSCs 3 days postmyocardial infarction (MI). CCR1-MSC-injected hearts exhibited a significant reduction in infarct size, reduced cardiomyocytes apoptosis and increased capillary density in injured myocardium 3 days after MI. Furthermore, intramyocardial injection of CCR1-MSCs prevented cardiac remodeling and restored cardiac function 4 weeks after MI. Our results demonstrate the in vitro and in vivo salutary effects of genetic modification of stem cells. Specifically, overexpression of chemokine receptor enhances the migration, survival and engraftment of MSCs, and may provide a new therapeutic strategy for the injured myocardium.

  11. Human migration, protected areas, and conservation outreach in Tanzania.

    Science.gov (United States)

    Salerno, Jonathan D; Borgerhoff Mulder, Monique; Kefauver, Shawn C

    2014-06-01

    A recent discussion debates the extent of human in-migration around protected areas (PAs) in the tropics. One proposed argument is that rural migrants move to bordering areas to access conservation outreach benefits. A counter proposal maintains that PAs have largely negative effects on local populations and that outreach initiatives even if successful present insufficient benefits to drive in-migration. Using data from Tanzania, we examined merits of statistical tests and spatial methods used previously to evaluate migration near PAs and applied hierarchical modeling with appropriate controls for demographic and geographic factors to advance the debate. Areas bordering national parks in Tanzania did not have elevated rates of in-migration. Low baseline population density and high vegetation productivity with low interannual variation rather than conservation outreach explained observed migration patterns. More generally we argue that to produce results of conservation policy significance, analyses must be conducted at appropriate scales, and we caution against use of demographic data without appropriate controls when drawing conclusions about migration dynamics. © 2014 Society for Conservation Biology.

  12. Cancer Stem-Like Cells Enriched in Panc-1 Spheres Possess Increased Migration Ability and Resistance to Gemcitabine

    Science.gov (United States)

    Yin, Tao; Wei, Hongji; Gou, Shanmiao; Shi, Pengfei; Yang, Zhiyong; Zhao, Gang; Wang, Chunyou

    2011-01-01

    Pancreatic cancer is one of the most lethal malignancies with poor prognosis. Previously, we found that a subpopulation of cancer stem cells (CSCs) in the Panc-1 pancreatic cancer cell line could propagate to form spheres. Here we characterized the malignant phenotypes of the pancreatic cancer stem CD44+/CD24+ cells, which were enriched under sphere forming conditions as analyzed by flow cytometry. These cells demonstrated increased resistance to gemcitabine and increased migration ability. Moreover, these cells exhibited epithelial to mesenchymal transition characterized by a decreased level of the epithelial marker E-cadherin and an increased level of the mesenchymal marker vimentin. Notably, abnormal expression of Bmi-1, ABCG2, Cyclin D1 and p16 were found in Panc-1 CSCs. Our results suggest that targeted inhibition of CSCs represents a novel therapeutic approach to overcome chemoresistance and metastasis of pancreatic cancer. PMID:21673909

  13. COMP-angiopoietin 1 increases proliferation, differentiation, and migration of stem-like cells through Tie-2-mediated activation of p38 MAPK and PI3K/Akt signal transduction pathways

    Energy Technology Data Exchange (ETDEWEB)

    Kook, Sung-Ho [Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences and School of Dentistry, Chonbuk National University, Jeonju (Korea, Republic of); Lim, Shin-Saeng [School of Dentistry and Dental Research Institute, Seoul National University, Seoul (Korea, Republic of); Cho, Eui-Sic; Lee, Young-Hoon; Han, Seong-Kyu; Lee, Kyung-Yeol [Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences and School of Dentistry, Chonbuk National University, Jeonju (Korea, Republic of); Kwon, Jungkee [College of Veterinary Medicine, Chonbuk National University, Jeonju (Korea, Republic of); Hwang, Jae-Won; Bae, Cheol-Hyeon [Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences and School of Dentistry, Chonbuk National University, Jeonju (Korea, Republic of); Seo, Young-Kwon [Research Institute of Biotechnology, Dongguk University, Seoul (Korea, Republic of); Lee, Jeong-Chae, E-mail: leejc88@jbnu.ac.kr [Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences and School of Dentistry, Chonbuk National University, Jeonju (Korea, Republic of)

    2014-12-12

    Highlights: • COMP-Ang1 induces Tie-2 activation in BMMSCs, but not in primary osteoblasts. • Tie-2 knockdown inhibits COMP-Ang1-stimulated proliferation and osteoblastogenesis. • Tie-2 knockdown prevents COMP-Ang1-induced activation of PI3K/Akt and p38 MAPK. • COMP-Ang1 induces migration of cells via activation of PI3K/Akt and CXCR4 pathways. • COMP-Ang1 stimulates in vivo migration of PDLSCs into a calvarial defect site of rats. - Abstract: Recombinant COMP-Ang1, a chimera of angiopoietin-1 (Ang1) and a short coiled-coil domain of cartilage oligomeric matrix protein (COMP), is under consideration as a therapeutic agent capable of inducing the homing of cells with increased angiogenesis. However, the potentials of COMP-Ang1 to stimulate migration of mesenchymal stem cells (MSCs) and the associated mechanisms are not completely understood. We examined the potential of COMP-Ang1 on bone marrow (BM)-MSCs, human periodontal ligament stem cells (PDLSCs), and calvarial osteoblasts. COMP-Ang1 augmented Tie-2 induction at protein and mRNA levels and increased proliferation and expression of runt-related transcription factor 2 (Runx2), osterix, and CXCR4 in BMMSCs, but not in osteoblasts. The COMP-Ang1-mediated increases were inhibited by Tie-2 knockdown and by treating inhibitors of phosphoinositide 3-kinase (PI3K), LY294002, or p38 mitogen-activated protein kinase (MAPK), SB203580. Phosphorylation of p38 MAPK and Akt was prevented by siRNA-mediated silencing of Tie-2. COMP-Ang1 also induced in vitro migration of BMMSCs and PDLSCs. The induced migration was suppressed by Tie-2 knockdown and by CXCR4-specific peptide antagonist or LY294002, but not by SB203580. Furthermore, COMP-Ang1 stimulated the migration of PDLSCs into calvarial defect site of rats. Collectively, our results demonstrate that COMP-Ang1-stimulated proliferation, differentiation, and migration of progenitor cells may involve the Tie-2-mediated activation of p38 MAPK and PI3K/Akt pathways.

  14. COMP-angiopoietin 1 increases proliferation, differentiation, and migration of stem-like cells through Tie-2-mediated activation of p38 MAPK and PI3K/Akt signal transduction pathways

    International Nuclear Information System (INIS)

    Kook, Sung-Ho; Lim, Shin-Saeng; Cho, Eui-Sic; Lee, Young-Hoon; Han, Seong-Kyu; Lee, Kyung-Yeol; Kwon, Jungkee; Hwang, Jae-Won; Bae, Cheol-Hyeon; Seo, Young-Kwon; Lee, Jeong-Chae

    2014-01-01

    Highlights: • COMP-Ang1 induces Tie-2 activation in BMMSCs, but not in primary osteoblasts. • Tie-2 knockdown inhibits COMP-Ang1-stimulated proliferation and osteoblastogenesis. • Tie-2 knockdown prevents COMP-Ang1-induced activation of PI3K/Akt and p38 MAPK. • COMP-Ang1 induces migration of cells via activation of PI3K/Akt and CXCR4 pathways. • COMP-Ang1 stimulates in vivo migration of PDLSCs into a calvarial defect site of rats. - Abstract: Recombinant COMP-Ang1, a chimera of angiopoietin-1 (Ang1) and a short coiled-coil domain of cartilage oligomeric matrix protein (COMP), is under consideration as a therapeutic agent capable of inducing the homing of cells with increased angiogenesis. However, the potentials of COMP-Ang1 to stimulate migration of mesenchymal stem cells (MSCs) and the associated mechanisms are not completely understood. We examined the potential of COMP-Ang1 on bone marrow (BM)-MSCs, human periodontal ligament stem cells (PDLSCs), and calvarial osteoblasts. COMP-Ang1 augmented Tie-2 induction at protein and mRNA levels and increased proliferation and expression of runt-related transcription factor 2 (Runx2), osterix, and CXCR4 in BMMSCs, but not in osteoblasts. The COMP-Ang1-mediated increases were inhibited by Tie-2 knockdown and by treating inhibitors of phosphoinositide 3-kinase (PI3K), LY294002, or p38 mitogen-activated protein kinase (MAPK), SB203580. Phosphorylation of p38 MAPK and Akt was prevented by siRNA-mediated silencing of Tie-2. COMP-Ang1 also induced in vitro migration of BMMSCs and PDLSCs. The induced migration was suppressed by Tie-2 knockdown and by CXCR4-specific peptide antagonist or LY294002, but not by SB203580. Furthermore, COMP-Ang1 stimulated the migration of PDLSCs into calvarial defect site of rats. Collectively, our results demonstrate that COMP-Ang1-stimulated proliferation, differentiation, and migration of progenitor cells may involve the Tie-2-mediated activation of p38 MAPK and PI3K/Akt pathways

  15. Nurse migration from India: a literature review.

    Science.gov (United States)

    Garner, Shelby L; Conroy, Shelley F; Bader, Susan Gerding

    2015-12-01

    A profound nursing shortage exists in India where nurses are increasingly outmigrating to practice nursing in surrounding countries and abroad. This is important globally because countries with the lowest nursing and healthcare workforce capacities have the poorest health outcomes. This review sought to synthesize and unify the evidence about nurse migration from India and includes a look at nurse retention within India. A comprehensive literature review was performed to synthesize and unify both qualitative and quantitative research. Bibliographic databases searched included CINAHL, MEDLINE, PsycINFO, and EconLit using associated keywords for empirical and descriptive literature published between January 2004 and May 2014. Hand searches of the Nursing Journal of India from 2004 to February 2014 and the Journal of Nursing Research Society of India from its inception in 2007-February 2014 were also completed. 29 studies were selected and analyzed for the review. Data were appraised for quality; reduced through sub-categorization; extracted; and coded into a framework. Thematic interpretation occurred through comparing and contrasting performed by multiple reviewers. Findings included an exponential growth in nurse recruitment efforts, nurse migration, and a concomitant growth in educational institutions within India with regional variations in nurse migration patterns. Decision-making factors for migration were based on working conditions, salience of family, and the desire for knowledge, skill, technology, adventure and personal enrichment. Challenges associated with migration included questionable recruiting practices, differing scopes of practice encountered after migration and experiences of racism and cultural differences. A shift toward a positive transformation of nursing status in India has resulted in an increased respect for individual nurses and the profession of nursing. This was attributed to the increased globalization of nursing. Results from this

  16. T-plastin expression downstream to the calcineurin/NFAT pathway is involved in keratinocyte migration.

    Directory of Open Access Journals (Sweden)

    Cécilia Brun

    Full Text Available Cutaneous wound healing requires keratinocyte proliferation, migration and differentiation to restore the barrier function of the skin. The calcineurin/nuclear factor of activated-T-cell (NFAT signaling pathway has been recently shown to be involved in keratinocyte growth, differentiation and migration. It is induced by an increased intracellular calcium rate and its inhibition results in decreased capacities of keratinocytes to migrate. Nevertheless, the link between calcineurin activation and keratinocyte migration remains unknown. Recently, Orai1, a pore subunit of a store-operated calcium channel that favors calcium influx, was shown to play a critical role to control proliferation and migration of basal keratinocytes. Of interest, the actin-bundling T-plastin is crucial in cell motility through cross-linking to actin filament and its synthesis was shown to be induced by calcium influx and regulated by the calcineurin/NFAT pathway in tumor Sezary cells. We investigated herein the role of the calcineurin/NFAT pathway-dependent T-plastin in keratinocyte migration, by quantifying T-plastin expression in keratinocytes and by analyzing their migration under calcineurin inhibition or knockdown of NFAT2 or T-plastin. We did confirm the role of the calcineurin/NFAT pathway in keratinocyte migration as shown by their decreased capacities to migrate after FK506 treatment or siNFAT2 transfection in both scratching and Boyden assays. The expression of NFAT2 and T-plastin in keratinocytes was decreased under FK506 treatment, suggesting that T-plastin plays a role in keratinocyte migration downstream to the calcineurin/NFAT pathway. Accordingly, siRNA knockdown of T-plastin expression also decreased their migration capacities. Actin lamellipodia formation as well as FAK and β6-integrin expression were also significantly decreased after treatment with FK506 or siRNA, reinforcing that NFAT2-dependent T-plastin expression plays a role in keratinocyte

  17. Environmental drivers of human migration in drylands - A spatial picture

    NARCIS (Netherlands)

    Neumann, K.; Sietz, D.; Hilderink, H.; Janssen, P.; Kok, M.; Dijk, van H.

    2015-01-01

    It is widely accepted that environmental change can influence human migration. In particular, the environment plays a role in migration processes in drylands, in which environmental change—including increasing variability of rainfall, increasing frequency of droughts, chronic water shortage, and

  18. Migration of the Duraloc cup after 5 years.

    Science.gov (United States)

    Stihsen, Christoph; Pabinger, Christof; Radl, Roman; Rehak, Peter; Windhager, Reinhard

    2008-12-01

    The Duraloc cup is a frequently used metal-backed, porous-coated, hemispherical, press-fit acetabular component. Published data on loosening rates are contradictory. In this study we investigated migration patterns with computer-assisted Einzel-Bild-Roentgen-Analyse (EBRA) of 67 Duraloc 100 cups. Cup migration and clinical scores were analysed over a 5-year follow-up period. Median total migration of the Duraloc 100 cup was 1.21 mm at 5 years. Seventy-five percent of implants were radiologically stable at 2 years and 90% at 4 years. One cup loosened aseptically at 60 months, requiring revision. Cup diameters > or = 54 mm migrated significantly more than cups < 54 mm in diameter (p = 0.029 at 4 years). There was a significant correlation between high polyethylene wear and further migrating cups within the first post-operative year (p = 0.035 at 12 months). Our analysis revealed significantly higher wear in males (p = 0.029 at 4 years). Radiological loosening at two years could be calculated using receiver-operating characteristic curve analysis, and 1.2 mm as an adequate threshold value (sensitivity = 100%, specificity = 89%).

  19. Evaluation of gas migration characteristics of compacted bentonite and Ca-bentonite mixture

    International Nuclear Information System (INIS)

    Tanaka, Yukihisa; Hironaga, Michihiko

    2014-01-01

    In the current concept of subsurface disposal and near-surface pit disposal for low level radioactive waste, compacted bentonite and Ca-bentonite mixture will be used as an engineered barrier mainly for inhibiting migration of radioactive nuclides, respectively. Hydrogen gas can be generated inside the engineered barrier of subsurface disposal facilities mainly by anaerobic corrosion of metals used for containers, etc. Hydrogen gas can be also generated inside the engineered barrier of near-surface pit disposal facilities mainly by the chemical interaction between aluminum and the alkaline component of cement, or water. If the gas generation rate exceeds the diffusion rate of gas molecules inside of the compacted bentonite and Ca-bentonite mixture, gas will accumulate in the void space inside of the compacted bentonite and Ca-bentonite mixture until breakthrough occurs. It is expected to be not easy for gas to entering into the compacted bentonite mixture as a discrete gaseous phase because the pore of the compacted bentonite and Ca-bentonite mixture is so minute. Therefore in this study, the gas migration characteristics and the effect of gas migration on the hydraulic conductivity of the compacted bentonite and Ca-bentonite mixture are investigated by the gas migration tests. The applicability of the two phase flow model without considering deformability of the specimen is investigated. The applicability of the model of two phase flow through deformable porous media, which was originally developed by CRIEPI, is also investigated. Results of this study imply that : (1) Gas migration mechanism of the compacted bentonite and Ca-bentonite mixture is revealed through gas migration test. (2) Hydraulic conductivity measured after the large gas breakthrough is substantially the same that measured before the gas migration test. (3) Stress change, pore-water pressure change and volume change of the specimen during the gas migration test can be reproduced by the numerical

  20. 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.

  1. HIV Prevention among Mexican Migrants at Different Migration Phases: Exposure to Prevention Messages and Association With Testing Behaviors

    Science.gov (United States)

    Martinez-Donate, Ana P.; Rangel, M. Gudelia; Zhang, Xiao; Simon, Norma-Jean; Rhoads, Natalie; Gonzalez-Fagoaga, J. Eduardo; Gonzalez, Ahmed Asadi

    2016-01-01

    Mobile populations are at increased risk for HIV infection. Exposure to HIV prevention messages at all phases of the migration process may help decrease im/migrants’ HIV risk. We investigated levels of exposure to HIV prevention messages, factors associated with message exposure, and the association between exposure to prevention messages and HIV testing behavior among Mexican im/migrants at different phases of the migration process. We conducted a cross-sectional, probability survey of Mexican im/migrants (N=3,149) traveling through the border city of Tijuana, Mexico. The results indicate limited exposure to prevention messages (57%–75%) and suboptimal last 12-month HIV testing rates (14%–25%) across five migration phases. Compared to pre-departure levels (75%), exposure to messages decreases at all post-departure migration phases (57%–63%, pmigration continuum. PMID:26595267

  2. Family migration and employment: the importance of migration history and gender.

    Science.gov (United States)

    Bailey, A J; Cooke, T J

    1998-01-01

    "This article uses event history data to specify a model of employment returns to initial migration, onward migration, and return migration among newly married persons in the U.S. Husbands are more likely to be full-time employed than wives, and being a parent reduces the employment odds among married women. Employment returns to repeated migration differ by gender, with more husbands full-time employed after onward migration and more wives full-time employed after return migration events. We interpret these empirical findings in the context of family migration theory, segmented labor market theory, and gender-based responsibilities." Data are from the National Longitudinal Survey of Youth from 1979 to 1991. excerpt

  3. Increasing the graduation rates of minority medical students.

    Science.gov (United States)

    Payne, J L; Nowacki, C M; Girotti, J A; Townsel, J; Plagge, J C; Beckham, T W

    1986-05-01

    The University of Illinois College of Medicine has operated a program since 1969 to recruit minority students into the college and to increase the graduation rates of these students once they enroll. Known as the Medical Opportunities Program (MOP) until 1978, the program was expanded in 1978 and renamed the Urban Health Program (UHP). The authors of the present paper discuss the results of these programs, particularly the effect of granting minority students delays in completing graduation requirements. The MOP (1969 through 1978) increased graduation rates for minority students from 55 percent for those who graduated on time to 81 percent for both on-time and delayed graduates. Under the first seven years of the UHP (1979 through 1985), more minority students have been offered places, and more have enrolled than in the 10 years of the MOP. The retention rate under the UHP, if it holds, will be higher than that under the MOP. For the combined MOP-UHP period, the retention rate for minority students was 88 percent; 69.8 percent of the graduates were on time, and 30.2 were delayed.

  4. 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...

  5. 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…

  6. DEFINING HUMAN MIGRATION – A POLICY MAKERS PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Paul-Panfil IVAN

    2015-06-01

    Full Text Available Migration is a global phenomenon gradually increased in scope, impact and complexity. Practically all countries are simultaneously countries of destination, origin and transit for migrants. Traditionally migration flows are complemented by new changes generated by economic, demographic, political or social conditions, and these trends affect both the size and structure of the migrant population and also economies and societies. Of course this has sparked international interest from various NGOs and by the European Union and the United Nations. This paper aims to present the vision of international organizations concerned with migration and how they define migration and its typologies.

  7. Migration: a concept analysis from a nursing perspective.

    Science.gov (United States)

    Freeman, Michelle; Baumann, Andrea; Blythe, Jennifer; Fisher, Anita; Akhtar-Danesh, Noori

    2012-05-01

      This article is a report of a concept analysis of nurse migration.   International migration is increasing and nurse migrants are active participants in this movement. Migration is a complex term and can be examined from a range of perspectives. Analysis of nurse migration is needed to guide policy, practice and research.   A literature search was undertaken using electronic literature indexes, specific journals and websites, internet search engines and hand searches. No timeframe was placed on the search. Most literature found was published between 2001 and 2009. A sample of 80 documents met the inclusion criteria.   Walker and Avant's approach guided the analysis.   Nurse migration can be defined by five attributes: the motivation and decisions of individuals; external barriers and facilitators; freedom of choice to migrate; freedom to migrate as a human right, and dynamic movement. Antecedents of migration include the political, social, economic, legal, historical and educational forces that comprise the push and pull framework. The consequences of migration are positive or negative depending on the viewpoint and its affect on the individual and other stakeholders such as the source country, destination country, healthcare systems and the nursing profession.   This concept analysis clarified the complexities surrounding nurse migration. A nursing-specific middle-range theory was proposed to guide the understanding and study of nurse migration. © 2011 Blackwell Publishing Ltd.

  8. Procedure for determining the optimum rate of increasing shaft depth

    Energy Technology Data Exchange (ETDEWEB)

    Durov, E.M.

    1983-03-01

    Presented is an economic analysis of increasing shaft depth during mine modernization. Investigations carried out by the Yuzhgiproshakht Institute are analyzed. The investigations are aimed at determining the optimum shaft sinking rate (the rate which reduces investment to the minimum). The following factors are considered: coal output of a mine (0.9, 1.2, 1.5 and 1.8 Mt/year), depth at which the new mining level is situated (600, 800, 1200, 1400 and 1600 m), four schemes of increasing depth of 2 central shafts (rock hoisting to ground surface, rock hoisting to the existing level, rock haulage to the developed level, rock haulage to the level being developed using a large diameter borehole drilled from the new level to the shaft bottom and enlarged from shaft bottom to the new level), shaft sinking rate (10, 20, 30, 40, 50 and 60 m/month), range of increasing shaft depth (the difference between depth of the shaft before and after increasing its depth by 100, 200, 300 and 400 m). Comparative evaluations show that the optimum shaft sinking rate depends on the scheme for rock hoisting (one of 4 analyzed), range of increasing shaft depth and gas content in coal seams. The optimum shaft sinking rate ranges from 20 to 40 m/month in coal mines with low methane content and from 20 to 30 m/month in gassy coal mines. The planned coal output of a mine does not influence the optimum shaft sinking rate.

  9. An Empirical Study on the Migration Among Young Skilled and Creative People

    Directory of Open Access Journals (Sweden)

    Marta-Christina Suciu

    2017-08-01

    Full Text Available In the context of a knowledge and innovative-based society and economy, smart and creative cities are attracting an increasing number of young people, most of them being gifted, very talented students and high-skilled workforce, with multiple competences. These young people are pro-active and they involve themselves on enhancing the progress of the community in which they are living. Many cities are facing a higher rate of brain drain, as a consequence of the quality of life and the low level of wages considering also a reduce level of acceptance and implementation of innovative solutions. In the last decades migration phenomenon had been amplified and there is an increased young people migration from emergent countries to the innovation driven countries, witch assure more financial stability and favourable conditions to contribute to both personal and professional development for its residents. Through an empiric research, we have identified the most important factors which contribute to the amplified migration among youths. We have also highlighted the motivational elements for returning to homeland, when the socio-economic situation is favourable. The paper includes also a set of recommendations that could create a proper framework to attract talented, skilled and creative youth, regardless their origin country.

  10. Risk factors for venous port migration in a single institute in Taiwan.

    Science.gov (United States)

    Fan, Wen-Chieh; Wu, Cheng-Han; Tsai, Ming-Ju; Tsai, Ying-Ming; Chang, Hsu-Liang; Hung, Jen-Yu; Chen, Pei-Huan; Yang, Chih-Jen

    2014-01-14

    An implantable port device provides an easily accessible central route for long-term chemotherapy. Venous catheter migration is one of the rare complications of venous port implantation. It can lead to side effects such as pain in the neck, shoulder, or ear, venous thrombosis, and even life-threatening neurologic problems. To date, there are few published studies that discuss such complications. This retrospective study of venous port implantation in a single center, a Taiwan hospital, was conducted from January 2011 to March 2013. Venous port migration was recorded along with demographic and characteristics of the patients. Of 298 patients with an implantable import device, venous port migration had occurred in seven, an incidence rate of 2.3%. All seven were male and had received the Bard port Fr 6.6 which had smaller size than TYCO port Fr 7.5 and is made of silicon. Significantly, migration occurred in male patients (P = 0.0006) and in those with lung cancer (P = 0.004). Multivariable logistic regression analysis revealed that lung cancer was a significant risk factor for port migration (odds ratio: 11.59; P = 0.0059). The migration rate of the Bard port Fr 6.6 was 6.7%. The median time between initial venous port implantation and port migration was 35.4 days (range, 7 to 135 days) and 71.4% (5/7) of patients had port migration within 30 days after initial port implantation. Male sex and lung cancer are risk factors for venous port migration. The type of venous port is also an important risk factor.

  11. Rural-urban migration in a developing country: Botswana, Africa.

    Science.gov (United States)

    Tarver, J D; Miller, H M

    1987-01-01

    Trends in internal migration in Botswana are analyzed, with a focus on rural-urban migration. Data are from the 1981 census and from a survey carried out in 1979. The authors note that even though the predominance of subsistence agriculture acts as a deterrent to rural-urban migration, it is probable that the total and percentage of people living in urban areas will increase. However, the magnitude and pattern of future migration will fluctuate over time as social and economic conditions change.

  12. Differential migration and proliferation of geometrical ensembles of cell clusters

    International Nuclear Information System (INIS)

    Kumar, Girish; Chen, Bo; Co, Carlos C.; Ho, Chia-Chi

    2011-01-01

    Differential cell migration and growth drives the organization of specific tissue forms and plays a critical role in embryonic development, tissue morphogenesis, and tumor invasion. Localized gradients of soluble factors and extracellular matrix have been shown to modulate cell migration and proliferation. Here we show that in addition to these factors, initial tissue geometry can feedback to generate differential proliferation, cell polarity, and migration patterns. We apply layer by layer polyelectrolyte assembly to confine multicellular organization and subsequently release cells to demonstrate the spatial patterns of cell migration and growth. The cell shapes, spreading areas, and cell-cell contacts are influenced strongly by the confining geometry. Cells within geometric ensembles are morphologically polarized. Symmetry breaking was observed for cells on the circular pattern and cells migrate toward the corners and in the direction parallel to the longest dimension of the geometric shapes. This migration pattern is disrupted when actomyosin based tension was inhibited. Cells near the edge or corner of geometric shapes proliferate while cells within do not. Regions of higher rate of cell migration corresponded to regions of concentrated growth. These findings demonstrate that multicellular organization can result in spatial patterns of migration and proliferation.

  13. The migration game in habitat network: the case of tuna

    DEFF Research Database (Denmark)

    Mariani, Patrizio; Krivan, Vlastimil; MacKenzie, Brian

    2016-01-01

    migration in direction of increasing fitness should lead to the ideal free distribution (IFD) which is the evolutionary stable strategy of the habitat selection game. We introduce a migration game which focuses on migrating dynamics leading to the IFD for age-structured populations and in time varying...

  14. Data and methods in the environment-migration nexus

    DEFF Research Database (Denmark)

    Eklund, Lina; Romankiewicz, Clemens; Brandt, Martin Stefan

    2016-01-01

    The relationship between environment and migration has gained increased attention since the 1990s when the Intergovernmental Panel on Climate Change projected climate change to become a major driver of human migration. Evaluations of this relationship include both quantitative and qualitative ass....... Several case studies base their results on data at very coarse resolutions that have undergone strong modifications and generalizations. We argue that scale-related shortcomings must be considered in all stages of environment-migration research....... assessments. This review article introduces the concept of scale to environment-migration research as an important methodological issue for the reliability of conclusions drawn. The review of case studies shows that scale issues are highly present in environment-migration research but rarely discussed...

  15. Convergence and migration among provinces.

    Science.gov (United States)

    Helliwell, J F

    1996-04-01

    "Have regional disparities in Canada changed over the past thirty years? This paper assesses the robustness of earlier findings of convergence in the levels and growth rates of provincial per capita GDP, and then estimates the extent to which interprovincial and international migration is being influenced by regional differences in incomes and employment." excerpt

  16. Melt migration modeling in partially molten upper mantle

    Science.gov (United States)

    Ghods, Abdolreza

    The objective of this thesis is to investigate the importance of melt migration in shaping major characteristics of geological features associated with the partial melting of the upper mantle, such as sea-floor spreading, continental flood basalts and rifting. The partial melting produces permeable partially molten rocks and a buoyant low viscosity melt. Melt migrates through the partially molten rocks, and transfers mass and heat. Due to its much faster velocity and appreciable buoyancy, melt migration has the potential to modify dynamics of the upwelling partially molten plumes. I develop a 2-D, two-phase flow model and apply it to investigate effects of melt migration on the dynamics and melt generation of upwelling mantle plumes and focusing of melt migration beneath mid-ocean ridges. Melt migration changes distribution of the melt-retention buoyancy force and therefore affects the dynamics of the upwelling plume. This is investigated by modeling a plume with a constant initial melt of 10% where no further melting is considered. Melt migration polarizes melt-retention buoyancy force into high and low melt fraction regions at the top and bottom portions of the plume and therefore results in formation of a more slender and faster upwelling plume. Allowing the plume to melt as it ascends through the upper mantle also produces a slender and faster plume. It is shown that melt produced by decompressional melting of the plume migrates to the upper horizons of the plume, increases the upwelling velocity and thus, the volume of melt generated by the plume. Melt migration produces a plume which lacks the mushroom shape observed for the plume models without melt migration. Melt migration forms a high melt fraction layer beneath the sloping base of the impermeable oceanic lithosphere. Using realistic conditions of melting, freezing and melt extraction, I examine whether the high melt fraction layer is able to focus melt from a wide partial melting zone to a narrow region

  17. Increased heart rate variability during nondirective meditation.

    Science.gov (United States)

    Nesvold, Anders; Fagerland, Morten W; Davanger, Svend; Ellingsen, Øyvind; Solberg, Erik E; Holen, Are; Sevre, Knut; Atar, Dan

    2012-08-01

    Meditation practices are in use for relaxation and stress reduction. Some studies indicate beneficial cardiovascular health effects of meditation. The effects on the autonomous nervous system seem to vary among techniques. The purpose of the present study was to identify autonomic nerve activity changes during nondirective meditation. Heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS) were monitored in 27 middle-aged healthy participants of both genders, first during 20 min regular rest with eyes closed, thereafter practising Acem meditation for 20 min. Haemodynamic and autonomic data were collected continuously (beat-to-beat) and non-invasively. HRV and BPV parameters were estimated by power spectral analyses, computed by an autoregressive model. Spontaneous activity of baroreceptors were determined by the sequence method. Primary outcomes were changes in HRV, BPV, and BRS between rest and meditation. HRV increased in the low-frequency (LF) and high-frequency (HF) bands during meditation, compared with rest (p = 0.014, 0.013, respectively). Power spectral density of the RR-intervals increased as well (p = 0.012). LF/HF ratio decreased non-significantly, and a reduction of LF-BPV power was observed during meditation (p < 0.001). There was no significant difference in BRS. Respiration and heart rates remained unchanged. Blood pressure increased slightly during meditation. There is an increased parasympathetic and reduced sympathetic nerve activity and increased overall HRV, while practising the technique. Hence, nondirective meditation by the middle aged may contribute towards a reduction of cardiovascular risk.

  18. Methods of quantitative and qualitative analysis of bird migration with a tracking radar

    Science.gov (United States)

    Bruderer, B.; Steidinger, P.

    1972-01-01

    Methods of analyzing bird migration by using tracking radar are discussed. The procedure for assessing the rate of bird passage is described. Three topics are presented concerning the grouping of nocturnal migrants, the velocity of migratory flight, and identification of species by radar echoes. The height and volume of migration under different weather conditions are examined. The methods for studying the directions of migration and the correlation between winds and the height and direction of migrating birds are presented.

  19. Low- and high-dose laser irradiation effects on cell migration and destruction

    Science.gov (United States)

    Layton, Elivia; Gallagher, Kyra A.; Zukerman, Sara; Stevens, Brianna; Zhou, Feifan; Liu, Hong; Chen, Wei R.

    2018-02-01

    Metastases are the cause of more than 90 percent of cancer-related deaths. Current treatment methods, including chemotherapy, radiation, and surgery, fail to target the metastases effectively. One potential treatment for metastatic cancer is laser immunotherapy (LIT). LIT combines the use of a photothermal laser with an immunoadjuvant, Glycated Chitosan (GC). GC combined with single-walled carbon nanotubes (SWNTs) has proven to be a viable alternative to traditional cancer treatment methods, when under irradiation of laser with appropriate wavelength. In this study, the effects of low dose and high dose laser irradiation on metastatic pancreatic cancer cell migration were observed. It was found that low dose irradiation increased the migration rate, but the high dose irradiation significantly decreased the migration rate of the cancer cells. When using LIT, the goal is to kill tumor cells and to prompt the correct immune response. If the tumor were irradiated with a low dose, it would promote metastasis. If the dose of irradiation were too high, it would destroy the entire tumor and the immune response would not recognize the tumor. Therefore, the laser dose plays an important role in LIT, particularly when using SWNT as light absorbing agent. Our results from this study will delineate the optimal laser irradiation dose for destroying tumor cells and at the same time preserve and release tumor antigens as a precursor of antitumor immune response.

  20. Determinants of labour migration of elite sport coaches.

    Science.gov (United States)

    Orlowski, Johannes; Wicker, Pamela; Breuer, Christoph

    2016-09-01

    Previous research examining labour migration in sport focused on athletes in professional team sports. The purpose of this study is to analyse the factors influencing the migration probability of elite sport coaches in Germany (i.e. national coaches, state coaches, and coaches at Olympic training bases). From a theoretical perspective, labour migration of athletes is affected by economic, social, political, competitive, geographic and cultural factors. This study examines whether these factors can be applied to coaches. Primary data were collected using an online survey of elite sport coaches in Germany. Applying a conjoint design, respondents were presented with 10 migration scenarios leading to a sample size of n = 1860 for the empirical analysis. In the scenarios, the coaching position openings abroad differed in terms of income level, contract length, weekly workload, responsibility for personnel, reputation of coaching job, career perspectives, sporting performance of athletes, distance from Germany, and predominant job language. Coaches were asked for their migration probability contingent on the specific scenario. On average, migration probability was 24.2%. The results of regression analysis showed that higher income, contracts of longer duration, responsibility for personnel and speaking the respective language significantly increased the migration probability, while distances of nine flight hours and more, lower reputation and career perspectives reduced it. The findings have implications for policy-makers: they indicate in what areas the situation of coaches needs improvement to increase the likelihood of retaining elite sport coaches in the German sport system.

  1. Undocumented migration in response to climate change

    Science.gov (United States)

    Riosmena, Fernando; Hunter, Lori M.; Runfola, Daniel M.

    2016-01-01

    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. PMID:27570840

  2. 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.

  3. Further evidence for increased macrophage migration inhibitory factor expression in prostate cancer

    Directory of Open Access Journals (Sweden)

    Iczkowski Kenneth A

    2005-07-01

    Full Text Available Abstract Background Macrophage migration inhibitory factor (MIF is a cytokine associated with prostate cancer, based on histologic evidence and circulating (serum levels. Recent studies from another laboratory failed to document these results. This study's aims were to extend and confirm our previous data, as well as to define possible mechanisms for the discrepant results. Additional aims were to examine MIF expression, as well as the location of MIF's receptor, CD74, in human prostatic adenocarcinoma compared to matched benign prostate. Methods MIF amounts were determined in random serum samples remaining following routine PSA screening by ELISA. Native, denaturing and reducing polyacrylamide gels and Western blot analyses determined the MIF form in serum. Prostate tissue arrays were processed for MIF in situ hybridization and immunohistochemistry for MIF and CD74. MIF released into culture medium from normal epithelial, LNCaP and PC-3 cells was detected by Western blot analysis. Results Median serum MIF amounts were significantly elevated in prostate cancer patients (5.87 ± 3.91 ng/ml; ± interquartile range; n = 115 compared with patients with no documented diagnosis of prostate cancer (2.19 ± 2.65 ng/ml; n = 158. ELISA diluent reagents that included bovine serum albumin (BSA significantly reduced MIF serum detection (p Conclusion Increased serum MIF was associated with prostate cancer. Diluent reagents that included BSA resulted in MIF serum immunoassay interference. In addition, significant amounts of complexed MIF (180 kDa under denaturing conditions by Western blot found in the serum do not bind to the MIF capture antibody. Increased MIF mRNA expression was observed in prostatic adenocarcinoma compared to benign tissue from matched samples, supporting our earlier finding of increased MIF gene expression in prostate cancer.

  4. Migration and Well-being: Beyond the Macrosystem

    Directory of Open Access Journals (Sweden)

    Dina Birman

    2011-11-01

    Full Text Available This commentary reviews the contributions of the 6 papers to the emerging focus on migration within community psychology. This collection of articles on migration and community represents a growing interest in the field in immigration issues in general, and a community psychology focus on these issues in particular. The papers span a range of issues raised by migration in a variety of different contexts. The papers reflect principles of community psychology by articulating a perspective on migration and its outcomes within national and global contexts. Taken together, these articles demonstrate the increasing mutual enrichment of immigration and community research. The articles suggest the need to continue to articulate psychological constructs as transactional and contextual across multiple levels of analysis.

  5. Does sex speed up evolutionary rate and increase biodiversity?

    NARCIS (Netherlands)

    Melian, Carlos J.; Alonso, David; Allesina, Stefano; Condit, Richard S.; Etienne, Rampal S.

    Most empirical and theoretical studies have shown that sex increases the rate of evolution, although evidence of sex constraining genomic and epigenetic variation and slowing down evolution also exists. Faster rates with sex have been attributed to new gene combinations, removal of deleterious

  6. Further evidence for increased macrophage migration inhibitory factor expression in prostate cancer

    International Nuclear Information System (INIS)

    Meyer-Siegler, Katherine L; Iczkowski, Kenneth A; Vera, Pedro L

    2005-01-01

    Macrophage migration inhibitory factor (MIF) is a cytokine associated with prostate cancer, based on histologic evidence and circulating (serum) levels. Recent studies from another laboratory failed to document these results. This study's aims were to extend and confirm our previous data, as well as to define possible mechanisms for the discrepant results. Additional aims were to examine MIF expression, as well as the location of MIF's receptor, CD74, in human prostatic adenocarcinoma compared to matched benign prostate. MIF amounts were determined in random serum samples remaining following routine PSA screening by ELISA. Native, denaturing and reducing polyacrylamide gels and Western blot analyses determined the MIF form in serum. Prostate tissue arrays were processed for MIF in situ hybridization and immunohistochemistry for MIF and CD74. MIF released into culture medium from normal epithelial, LNCaP and PC-3 cells was detected by Western blot analysis. Median serum MIF amounts were significantly elevated in prostate cancer patients (5.87 ± 3.91 ng/ml; ± interquartile range; n = 115) compared with patients with no documented diagnosis of prostate cancer (2.19 ± 2.65 ng/ml; n = 158). ELISA diluent reagents that included bovine serum albumin (BSA) significantly reduced MIF serum detection (p < 0.01). MIF mRNA was localized to prostatic epithelium in all samples, but cancer showed statistically greater MIF expression. MIF and its receptor (CD74) were localized to prostatic epithelium. Increased secreted MIF was detected in culture medium from prostate cancer cell lines (LNCaP and PC-3). Increased serum MIF was associated with prostate cancer. Diluent reagents that included BSA resulted in MIF serum immunoassay interference. In addition, significant amounts of complexed MIF (180 kDa under denaturing conditions by Western blot) found in the serum do not bind to the MIF capture antibody. Increased MIF mRNA expression was observed in prostatic

  7. Migration and the Wage-Settings Curve

    DEFF Research Database (Denmark)

    Brücker, Herbert; Jahn, Elke

    Germany on basis of a wage-setting curve. The wage-setting curve relies on the assumption that wages respond to a hange in the unemployment rate, albeit imperfectly. This allows one to derive the wage and employment effects of migration simultaneously in a general equilibrium framework. Using...

  8. Humic colloid-borne migration of uranium in sand columns

    International Nuclear Information System (INIS)

    Artinger, R.; Rabung, T.; Kim, J.I.; Sachs, S.; Schmeide, K.; Heise, K.H.; Bernhard, G.; Nitsche, H.

    2002-09-01

    Column experiments were carried out to investigate the influence of humic colloids on subsurface uranium migration. The columns were packed with well-characterized aeolian quartz sand and equilibrated with groundwater rich in humic colloids (dissolved organic carbon (DOC): 30 mg dm -3 ). U migration was studied under an Ar/1% CO 2 gas atmosphere as a function of the migration time, which was controlled by the flow velocity or the column length. In addition, the contact time of U with groundwater prior to introduction into a column was varied. U(VI) was found to be the dominant oxidation state in the spiked groundwater. The breakthrough curves indicate that U was transported as a humic colloid-borne species with a velocity up to 5% faster than the mean groundwater flow. The fraction of humic colloid-borne species increases with increasing prior contact time and also with decreasing migration time. The migration behavior was attributed to a kinetically controlled association/dissociation of U onto and from humic colloids and also a subsequent sorption of U onto the sediment surface. The column experiments provide an insight into humic colloid-mediated U migration in subsurface aquifers

  9. Gremlin-1 induces BMP-independent tumor cell proliferation, migration, and invasion.

    Directory of Open Access Journals (Sweden)

    Minsoo Kim

    Full Text Available Gremlin-1, a bone morphogenetic protein (BMP antagonist, is overexpressed in various cancerous tissues but its role in carcinogenesis has not been established. Here, we report that gremlin-1 binds various cancer cell lines and this interaction is inhibited by our newly developed gremlin-1 antibody, GRE1. Gremlin-1 binding to cancer cells was unaffected by the presence of BMP-2, BMP-4, and BMP-7. In addition, the binding was independent of vascular endothelial growth factor receptor-2 (VEGFR2 expression on the cell surface. Addition of gremlin-1 to A549 cells induced a fibroblast-like morphology and decreased E-cadherin expression. In a scratch wound healing assay, A549 cells incubated with gremlin-1 or transfected with gremlin-1 showed increased migration, which was inhibited in the presence of the GRE1 antibody. Gremlin-1 transfected A549 cells also exhibited increased invasiveness as well as an increased growth rate. These effects were also inhibited by the addition of the GRE1 antibody. In conclusion, this study demonstrates that gremlin-1 directly interacts with cancer cells in a BMP- and VEGFR2-independent manner and can induce cell migration, invasion, and proliferation.

  10. Japanese migration in contemporary Japan: economic segmentation and interprefectural migration.

    Science.gov (United States)

    Fukurai, H

    1991-01-01

    This paper examines the economic segmentation model in explaining 1985-86 Japanese interregional migration. The analysis takes advantage of statistical graphic techniques to illustrate the following substantive issues of interregional migration: (1) to examine whether economic segmentation significantly influences Japanese regional migration and (2) to explain socioeconomic characteristics of prefectures for both in- and out-migration. Analytic techniques include a latent structural equation (LISREL) methodology and statistical residual mapping. The residual dispersion patterns, for instance, suggest the extent to which socioeconomic and geopolitical variables explain migration differences by showing unique clusters of unexplained residuals. The analysis further points out that extraneous factors such as high residential land values, significant commuting populations, and regional-specific cultures and traditions need to be incorporated in the economic segmentation model in order to assess the extent of the model's reliability in explaining the pattern of interprefectural migration.

  11. 75 FR 81003 - Rate Increase Disclosure and Review

    Science.gov (United States)

    2010-12-23

    ... choice of any threshold makes it inevitable that unreasonable rate increases below the threshold will not... in the preliminary justification supplements, and does not conflict with, State laws specifying what...

  12. Rural-urban migration in Zambia and migrant ties to home villages.

    Science.gov (United States)

    Ogura, M

    1991-06-01

    Rural to urban migration patterns in Zambia and migrant ties to home villages are discussed 1st in terms of a statistical overview of migration and urbanization, and followed by an examination of lengthening stays in towns and ties to the home village based on other studies and the author's field research and random sampling in 6 urban areas of Zambia. The primary population centers are the copperbelt which comprises 45% of the total urban population, and Lusaka which is 24% of the total urban population. 31% of the total population reside in Lusaka, 7 mining towns, Kabwe, and Livingstone. Migration and a high rate of natural population growth are responsible for the urban growth. Recent economic difficulties have reduced the flow of migration to urban areas and lead to the out migration in copper towns. independence also has had an effect on migration, such that female migration increased along with male migration. Female migration reflects female educational advances and the changing practice of housewives accompanying husbands. The informal sector absorbs a great number of the migrant labor force. Income gaps between urban and rural areas also contribute to migration flows. Other magnets in urban areas are better educational opportunities, a water supply, and the lure of city lights. Since independence, migrants have increased their length of stay in towns but continue to maintain links with their home villages. 87.5% of mine workers are estimated as intending to go back to their villages. Before the mid-1970s it is estimated in a Ngombe squatter camp that 65% of employed male household heads had sent money home the prior year, 58% had visited home within the past 5 years, but 25% had never visited in 10 years. 58% intended to return home and 36% intended to stay permanently. The author's research between 1987-89 found 3 types of squatter villages: those retired and not returning to home villages such as Kansusuwa, those workers living in compounds where farm

  13. Increasing Nucleosome Occupancy Is Correlated with an Increasing Mutation Rate so Long as DNA Repair Machinery Is Intact

    Science.gov (United States)

    Taylor, Jared F.; Khattab, Omar S.; Chen, Yu-Han; Chen, Yumay; Jacobsen, Steven E.; Wang, Ping H.

    2015-01-01

    Deciphering the multitude of epigenomic and genomic factors that influence the mutation rate is an area of great interest in modern biology. Recently, chromatin has been shown to play a part in this process. To elucidate this relationship further, we integrated our own ultra-deep sequenced human nucleosomal DNA data set with a host of published human genomic and cancer genomic data sets. Our results revealed, that differences in nucleosome occupancy are associated with changes in base-specific mutation rates. Increasing nucleosome occupancy is associated with an increasing transition to transversion ratio and an increased germline mutation rate within the human genome. Additionally, cancer single nucleotide variants and microindels are enriched within nucleosomes and both the coding and non-coding cancer mutation rate increases with increasing nucleosome occupancy. There is an enrichment of cancer indels at the theoretical start (74 bp) and end (115 bp) of linker DNA between two nucleosomes. We then hypothesized that increasing nucleosome occupancy decreases access to DNA by DNA repair machinery and could account for the increasing mutation rate. Such a relationship should not exist in DNA repair knockouts, and we thus repeated our analysis in DNA repair machinery knockouts to test our hypothesis. Indeed, our results revealed no correlation between increasing nucleosome occupancy and increasing mutation rate in DNA repair knockouts. Our findings emphasize the linkage of the genome and epigenome through the nucleosome whose properties can affect genome evolution and genetic aberrations such as cancer. PMID:26308346

  14. Increasing Nucleosome Occupancy Is Correlated with an Increasing Mutation Rate so Long as DNA Repair Machinery Is Intact.

    Directory of Open Access Journals (Sweden)

    Puya G Yazdi

    Full Text Available Deciphering the multitude of epigenomic and genomic factors that influence the mutation rate is an area of great interest in modern biology. Recently, chromatin has been shown to play a part in this process. To elucidate this relationship further, we integrated our own ultra-deep sequenced human nucleosomal DNA data set with a host of published human genomic and cancer genomic data sets. Our results revealed, that differences in nucleosome occupancy are associated with changes in base-specific mutation rates. Increasing nucleosome occupancy is associated with an increasing transition to transversion ratio and an increased germline mutation rate within the human genome. Additionally, cancer single nucleotide variants and microindels are enriched within nucleosomes and both the coding and non-coding cancer mutation rate increases with increasing nucleosome occupancy. There is an enrichment of cancer indels at the theoretical start (74 bp and end (115 bp of linker DNA between two nucleosomes. We then hypothesized that increasing nucleosome occupancy decreases access to DNA by DNA repair machinery and could account for the increasing mutation rate. Such a relationship should not exist in DNA repair knockouts, and we thus repeated our analysis in DNA repair machinery knockouts to test our hypothesis. Indeed, our results revealed no correlation between increasing nucleosome occupancy and increasing mutation rate in DNA repair knockouts. Our findings emphasize the linkage of the genome and epigenome through the nucleosome whose properties can affect genome evolution and genetic aberrations such as cancer.

  15. Increasing inhibitory input increases neuronal firing rate: why and when? Diffusion process cases

    Energy Technology Data Exchange (ETDEWEB)

    Feng Jianfeng [COGS, Sussex University (United Kingdom)]. E-mail: jf218@cam.ac.uk; Wei Gang [Department of Mathematics, Hong Kong Baptist University, Hong Kong (China)]. E-mail gwei@math.hkbu.edu.hk

    2001-09-21

    Increasing inhibitory input to single neuronal models, such as the FitzHugh-Nagumo model and the Hodgkin-Huxley model, can sometimes increase their firing rates, a phenomenon which we term inhibition-boosted firing (IBF). Here we consider neuronal models with diffusion approximation inputs, i.e. they share the identical first- and second-order statistics of the corresponding Poisson process inputs. Using the integrate-and-fire model and the IF-FHN model, we explore theoretically how and when IBF can happen. For both models, it is shown that there is a critical input frequency at which the efferent firing rate is identical when the neuron receives purely excitatory inputs or exactly balanced inhibitory and excitatory inputs. When the input frequency is lower than the critical frequency, IBF occurs. (author)

  16. Gas evolution and migration in repositories: current status

    International Nuclear Information System (INIS)

    Rees, J.H.; Rodwell, W.R.

    1988-04-01

    Considerable volumes of gas may be formed in a repository due to corrosion of metallic wastes and microbial degradation of certain organic wastes. The requirements for data and models to help understand the rate of formation of gases and their migration are described. The Nirex research programme in the area complements existing knowledge and takes additional priorities from the outcome of site assessments. Key areas currently being studied include: the rate of evolution of hydrogen from steel under anaerobic conditions; and of carbon dioxide and methane from cellulosic materials; characterisation of near- and far-field materials with respect to gas transport (permeabilities, capillary pressures, etc); and development of a comprehensive series of models covering gas evolution and migration in the near and far fields. (author)

  17. Modelling internal migration in Kenya: an econometric analysis with limited data.

    Science.gov (United States)

    Barber, G M; Milne, W J

    1988-09-01

    "In this paper the determinants of internal migration in Kenya are analyzed on the basis of a human capital model. Explanatory variables included in the specification are both economic (wage rates and employment rates) and noneconomic (for example, population density and educational attainment). Also incorporated are variables which reflect intervening opportunities.... The econometric results show that destination variables are important determinants of internal migration, as is distance between the districts. Further, the variables for the intervening opportunities add significantly to the explanatory power of the model." excerpt

  18. Sovereignty, human rights, and international migrations

    Directory of Open Access Journals (Sweden)

    Rossana Rocha Reis

    2006-01-01

    Full Text Available This article discusses the relationship between sovereignty and human rights concerning the elaboration of immigration policies. It deals with the role of the State in international migrations, the effects of the development of an international human rights legislation over the immigration question, and finally discusses the idea that the increasing international migration is leading the State to lose control over its population and territory, two central features of the sovereignty concept.

  19. The Globalisation of migration

    OpenAIRE

    Milan Mesić

    2002-01-01

    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 ...

  20. Linking behavior, physiology, and survival of Atlantic Salmon smolts during estuary migration

    Science.gov (United States)

    Stich, Daniel S.; Zydlewski, Gayle B.; Kocik, John F.; Zydlewski, Joseph D.

    2015-01-01

    Decreased marine survival is identified as a component driver of continued declines of Atlantic Salmon Salmo salar. However, estimates of marine mortality often incorporate loss incurred during estuary migration that may be mechanistically distinct from factors affecting marine mortality. We examined movements and survival of 941 smolts (141 wild and 800 hatchery-reared fish) released in freshwater during passage through the Penobscot River estuary, Maine, from 2005 to 2013. We related trends in estuary arrival date, movement rate, and survival to fish characteristics, migratory history, and environmental conditions in the estuary. Fish that experienced the warmest thermal history arrived in the estuary 8 d earlier than those experiencing the coolest thermal history during development. Estuary arrival date was 10 d later for fish experiencing high flow than for fish experiencing low flow. Fish released furthest upstream arrived in the estuary 3 d later than those stocked further downstream but moved 0.5 km/h faster through the estuary. Temporally, movement rate and survival in the estuary both peaked in mid-May. Spatially, movement rate and survival both decreased from freshwater to the ocean. Wild smolts arrived in the estuary later than hatchery fish, but we observed no change in movement rate or survival attributable to rearing history. Fish with the highest gill Na+, K+-ATPase activity incurred 25% lower mortality through the estuary than fish with the lowest gill Na+, K+-ATPase activity. Smolt survival decreased (by up to 40%) with the increasing number of dams passed (ranging from two to nine) during freshwater migration. These results underscore the importance of physiological preparedness on performance and the delayed, indirect effects of dams on survival of Atlantic Salmon smolts during estuary migration, ultimately affecting marine survival estimates.

  1. Glucagon infusion increases rate of purine synthesis de novo in rat liver

    International Nuclear Information System (INIS)

    Itakura, Mitsuo; Maeda, Noriaki; Tsuchiya, Masami; Yamashita, Kamejiro

    1987-01-01

    Based on the parallel increases of glucagon, the second peak of hepatic cAMP, and the rate of purine synthesis de novo in the prereplicative period in regenerating rate liver after a 70% hepatectomy, it was hypothesized that glucagon is responsible for the increased rate of purine synthesis de novo. To test this hypothesis, the effect of glucagon or dibutyryl cAMP infusion on the rate of purine synthesis de novo in rat liver was studied. Glucagon infusion but not insulin or glucose infusion increased the rate of purine synthesis de novo, which was assayed by [ 14 C]glycine or [ 14 C]formate incorporation, by 2.7- to 4.3-fold. Glucagon infusion increased cAMP concentrations by 4.9-fold and 5-phosphoribosyl-1-pyrophosphate concentrations by 1.5-fold in liver but did not change the specific activity of amidophosphoribosyltransferase or purine ribonucleotide concentrations. Dibutyryl cAMP infusion also increased the rate of purine synthesis de novo by 2.2- to 4.0-fold. Because glucagon infusion increased the rate of purine synthesis de novo in the presence of unchanged purine ribonucleotide concentrations, it is concluded that glucagon after infusion or in animals after a 70% hepatectomy is playing an anabolic role to increase the rate of purine synthesis de novo by increasing cAMP and 5-phosphoribosyl-1-pyrophosphate concentrations

  2. Dopamine Increases CD14+CD16+ Monocyte Migration and Adhesion in the Context of Substance Abuse and HIV Neuropathogenesis

    Science.gov (United States)

    Coley, Jacqueline S.; Calderon, Tina M.; Gaskill, Peter J.; Eugenin, Eliseo A.; Berman, Joan W.

    2015-01-01

    Drug abuse is a major comorbidity of HIV infection and cognitive disorders are often more severe in the drug abusing HIV infected population. CD14+CD16+ monocytes, a mature subpopulation of peripheral blood monocytes, are key mediators of HIV neuropathogenesis. Infected CD14+CD16+ monocyte transmigration across the blood brain barrier mediates HIV entry into the brain and establishes a viral reservoir within the CNS. Despite successful antiretroviral therapy, continued influx of CD14+CD16+ monocytes, both infected and uninfected, contributes to chronic neuroinflammation and the development of HIV associated neurocognitive disorders (HAND). Drug abuse increases extracellular dopamine in the CNS. Once in the brain, CD14+CD16+ monocytes can be exposed to extracellular dopamine due to drug abuse. The direct effects of dopamine on CD14+CD16+ monocytes and their contribution to HIV neuropathogenesis are not known. In this study, we showed that CD14+CD16+ monocytes express mRNA for all five dopamine receptors by qRT-PCR and D1R, D5R and D4R surface protein by flow cytometry. Dopamine and the D1-like dopamine receptor agonist, SKF38393, increased CD14+CD16+ monocyte migration that was characterized as chemokinesis. To determine whether dopamine affected cell motility and adhesion, live cell imaging was used to monitor the accumulation of CD14+CD16+ monocytes on the surface of a tissue culture dish. Dopamine increased the number and the rate at which CD14+CD16+ monocytes in suspension settled to the dish surface. In a spreading assay, dopamine increased the area of CD14+CD16+ monocytes during the early stages of cell adhesion. In addition, adhesion assays showed that the overall total number of adherent CD14+CD16+ monocytes increased in the presence of dopamine. These data suggest that elevated extracellular dopamine in the CNS of HIV infected drug abusers contributes to HIV neuropathogenesis by increasing the accumulation of CD14+CD16+ monocytes in dopamine rich brain

  3. Preliminary study of depleted uranium aerosol migration in soils

    International Nuclear Information System (INIS)

    Guo Zhiying; Yu Shui; Zheng Yonghong; Liang Yueqin; Liu Liping; Song Zhanjun; Zhao Fa

    2007-01-01

    Objective: To explore the depth of depleted uranium (DU) migration in six main kinds of Chinese soils and the pollution of the groundwater made by DU migration. Methods: With the circulating column model and the inductively coupled plasma-mass spectrometry (ICP-MS), concentration of uranium and the ratio of 235 U/ 238 U in different depth soils and in the corresponding filter liquids had been determined. Results: In the acid rain of pH 3.0, the migration depth of DU in the washed soil and brown soil were 6-8 cm and 4-6 cm, respectively. And with the increment of the acidity of the acid rain, the migration depth of DU in the soils was increased. The migration depth of DU in the 6 types soils was 0-4 cm. The distributed factor between the liquids and soils was lower than 0.004, and the concentration of uranium in the filter liquids was 0.05-10.33 μg/L. Conclusions: The migration depth of DU in soils can be increased by the acid rain, and the majority of DU was stayed in the upper soils and DU pollution might exist for long time, but the probability of groundwater pollution was low. The migration capability of DU was interrelated with the concentration of organic compound in the soils. (authors)

  4. Migration and Remittances : Recent Developments and Outlook - Transit Migration

    OpenAIRE

    World Bank Group

    2018-01-01

    This Migration and Development Brief reports global trends in migration and remittance flows, as well as developments related to the Global Compact on Migration (GCM), and the Sustainable Development Goal (SDG) indicators for volume of remittances as percentage of gross domestic product (GDP) (SDG indicator 17.3.2), reducing remittance costs (SDG indicator 10.c.1) and recruitment costs (SD...

  5. Structural-equation models of migration: an example from the Upper Midwest USA.

    Science.gov (United States)

    Cadwallader, M

    1985-01-01

    "To date, most migration models have been specified in terms of a single equation, whereby a set of regional characteristics are used to predict migration rates for various kinds of spatial units. These models are inadequate in at least two respects. First, they omit any causal links between the explanatory variables, thus ignoring indirect effects between these variables and migration. Second, they ignore the possibility of reciprocal causation, or feedback effects, between migration and the explanatory variables...." The author uses data for State Economic Areas to construct a path model and simultaneous-equation model to identify both indirect and feedback effects on migration in the Upper Midwestern United States. "On the basis of the path model, it is suggested that the direct effects of many variables on migration are at least partially offset by the indirect effects, whereas the simultaneous-equation model emphasizes the reciprocal relationship between income and migration." excerpt

  6. The effect of stratigraphic dip on brine inflow and gas migration at the Waste Isolation Pilot Plant

    International Nuclear Information System (INIS)

    Webb, S.W.; Larson, K.W.

    1996-02-01

    The natural dip of the Salado Formation at the Waste Isolation Pilot Plant (WIPP), although regionally only about 111, has the potential to affect brine inflow and gas-migration distances due to buoyancy forces. Current models, including those in WIPP Performance Assessment calculations, assume a perfectly horizontal repository and stratigraphy. With the addition of buoyancy forces due to the dip, brine and gas flow patterns can be affected. Brine inflow may increase due to countercurrent flow, and gas may preferentially migrate up dip. This scoping study has used analytical and numerical modeling to evaluate the impact of the dip on brine inflow and gas-migration distances at the WIPP in one, two, and three dimensions. Sensitivities to interbed permeabilities, two-phase curves, gas-generation rates, and interbed fracturing were studied

  7. The effect of stratigraphic dip on brine inflow and gas migration at the Waste Isolation Pilot Plant

    Energy Technology Data Exchange (ETDEWEB)

    Webb, S.W. [Sandia National Labs., Albuquerque, NM (United States); Larson, K.W. [INTERA, Inc., Albuquerque, NM (United States)

    1996-02-01

    The natural dip of the Salado Formation at the Waste Isolation Pilot Plant (WIPP), although regionally only about 111, has the potential to affect brine inflow and gas-migration distances due to buoyancy forces. Current models, including those in WIPP Performance Assessment calculations, assume a perfectly horizontal repository and stratigraphy. With the addition of buoyancy forces due to the dip, brine and gas flow patterns can be affected. Brine inflow may increase due to countercurrent flow, and gas may preferentially migrate up dip. This scoping study has used analytical and numerical modeling to evaluate the impact of the dip on brine inflow and gas-migration distances at the WIPP in one, two, and three dimensions. Sensitivities to interbed permeabilities, two-phase curves, gas-generation rates, and interbed fracturing were studied.

  8. A computer model for DNAPL potential migration study

    International Nuclear Information System (INIS)

    Yan, S.; Landry, G.R.; Tate, T.

    1994-01-01

    A computer model, named DNAPMIG (DNAPL Potential Migration), was developed to calculate the dense nonaqueous phase liquid (DNAPL) critical length required to initiate movement and direction of potential migration at locations within an area of interest. The model takes into consideration the potentiometric gradient, bottom structure elevation, DNAPL density, interfacial tension, contact angle, soil grain size, partitioning coefficient, effective solubility, and water saturation. The model is interfaced with SURFER graphics software to use vectors to indicate the DNAPL critical length and the potential migration direction. The potential for DNAPL existence and migration at a specific site can be estimated by relating chemical concentration in the ground water to its solubility limit and the DNAPL critical length. The possibility of vertical migration can also be determined. This model can be used to determine and compare the effectiveness of existing or alternative recovery well systems to capture a DNAPL plume or arrest its movement; to help determine optimum locations and pumping rates of recovery wells; and to help determine the optimum location of environmental borings to locate DNAPL. This paper presents two hypothetical examples and two site applications in south Louisiana

  9. Regime shifts in shallow lakes: the importance of seasonal fish migration

    DEFF Research Database (Denmark)

    Brönmark, Christer; Brodersen, Jakob; Chapman, Ben B.

    2010-01-01

    . Our earlier research shows that a large proportion of zooplanktivorous fish populations in shallow lakes undertake seasonal migrations where they leave the lake during winter and migrate back to the lake in spring. Based on our past research, we propose a number of scenarios of how feedback processes...... properties, including piscivore abundance and zooplankton productivity, affect the individual state of zooplanktivorous fish, such as growth rate or condition. Individual state, in turn, affects the relative proportion and timing of migrating zooplanktivorous fish. This change, in turn, may stabilize states...... between the individual and ecosystem levels may affect stability of alternative stable states in shallow lakes when mediated by fish migration. Migration effects on shallow lakes result from processes at different scales, from the individual to the ecosystem. Our earlier research has shown that ecosystem...

  10. Is the poleward migration of tropical cyclone maximum intensity associated with a poleward migration of tropical cyclone genesis?

    Science.gov (United States)

    Daloz, Anne Sophie; Camargo, Suzana J.

    2018-01-01

    A recent study showed that the global average latitude where tropical cyclones achieve their lifetime-maximum intensity has been migrating poleward at a rate of about one-half degree of latitude per decade over the last 30 years in each hemisphere. However, it does not answer a critical question: is the poleward migration of tropical cyclone lifetime-maximum intensity associated with a poleward migration of tropical cyclone genesis? In this study we will examine this question. First we analyze changes in the environmental variables associated with tropical cyclone genesis, namely entropy deficit, potential intensity, vertical wind shear, vorticity, skin temperature and specific humidity at 500 hPa in reanalysis datasets between 1980 and 2013. Then, a selection of these variables is combined into two tropical cyclone genesis indices that empirically relate tropical cyclone genesis to large-scale variables. We find a shift toward greater (smaller) average potential number of genesis at higher (lower) latitudes over most regions of the Pacific Ocean, which is consistent with a migration of tropical cyclone genesis towards higher latitudes. We then examine the global best track archive and find coherent and significant poleward shifts in mean genesis position over the Pacific Ocean basins.

  11. Upstream migration of Pacific lampreys in the John Day River, Oregon: Behavior, timing, and habitat use

    Science.gov (United States)

    Robinson, T. Craig; Bayer, J.M.

    2005-01-01

    Adult Pacific lamprey migration and habitat preferences for over-winter holding and spawning, and larval rearing in tributaries to the Columbia River are not well understood. The John Day River is one such tributary where larval and adult stages of this species have been documented, and its free-flowing character provided the opportunity to study migration of Pacific lampreys unimpeded by passage constraints. Forty-two adult Pacific lampreys were captured in the John Day River near its mouth during their upstream migration. Pacific lampreys were surgically implanted with radio transmitters and released onsite, and tracked by fixed-site, aerial, and terrestrial telemetry methods for nearly one year. Adults moved upstream exclusively at night, with a mean rate of 11.1 ?? 6.3 km/day. They halted upstream migration by September, and held a single position for approximately six months in the lateral margins of riffles and glides, using boulders for cover. More than half of Pacific lampreys resumed migration in March before ending movement in early May. Pacific lampreys that resumed migration in spring completed a median of 87% of their upstream migration before over-winter holding. Upon completing migration. Pacific lampreys briefly held position before beginning downstream movement at the end of May. Though not directly observed, halting migration and movement downstream were likely the result of spawning and death. Gains in adult Pacific lamprey passage through the Columbia River hydrosystem and tributaries may be made by improvements that would expedite migration during spring and summer and increase the quantity and variety of cover and refuge opportunities. ?? 2005 by the Northwest Scientific Association. All rights reserved.

  12. Effects of seed migration on post-implant dosimetry of prostate brachytherapy

    International Nuclear Information System (INIS)

    Gao, M.; Wang, J. Z.; Nag, S.; Gupta, N.

    2007-01-01

    Brachytherapy using permanent seed implants has been an effective treatment for prostate cancer. However, seeds will migrate after implant, thus making the evaluation of post-implant dosimetry difficult. In this study, we developed a computer program to simulate seed migration and analyzed dosimetric changes due to seed migration at various migration amounts. The study was based on 14 patients treated with Pd-103 at the James Cancer Hospital. Modeling of seed migration, including direction, distance as well as day of migration, was based on clinical observations. Changes of commonly used dosimetric parameters as a function of migration amount (2, 4, 6 mm respectively), prostate size (from 20 to 90 cc), and prostate region (central vs peripheral) were studied. Change of biological outcome (tumor control probability) due to migration was also estimated. Migration reduced prostate D90 to 99±2% of original value in 2 mm migration, and the reduction increased to 94±6% in 6 mm migration. The reduction of prostate dose led to a 14% (40%) drop in the tumor control probability for 2 mm (6 mm) migration, assuming radiosensitive tumors. However, migration has less effect on a prostate implanted with a larger number of seeds. Prostate V100 was less sensitive to migration than D90 since its mean value was still 99% of original value even in 6 mm migration. Migration also showed a different effect in the peripheral region vs the central region of the prostate, where the peripheral mean dose tended to drop more significantly. Therefore, extra activity implanted in the peripheral region during pre-plan can be considered. The detrimental effects of migration were more severe in terms of increasing the dose to normal structures, as rectum V50 may be 70% higher and urethra V100 may be 50% higher in the case of 6 mm migration. Quantitative knowledge of these effects is helpful in treatment planning and post-implant evaluation

  13. Fitness consequences of timing of migration and breeding in cormorants.

    Directory of Open Access Journals (Sweden)

    Phillip Gienapp

    Full Text Available In most bird species timing of breeding affects reproductive success whereby early breeding is favoured. In migratory species migration time, especially arrival at the breeding grounds, and breeding time are expected to be correlated. Consequently, migration time should also have fitness consequences. However, in contrast to breeding time, evidence for fitness consequences of migration time is much more limited. Climate change has been shown to negatively affect the synchrony between trophic levels thereby leading to directional selection on timing but again direct evidence in avian migration time is scarce. We here analysed fitness consequences of migration and breeding time in great cormorants and tested whether climate change has led to increased selection on timing using a long-term data set from a breeding colony on the island of Vorsø (Denmark. Reproductive success, measured as number of fledglings, correlated with breeding time and arrival time at the colony and declined during the season. This seasonal decline became steeper during the study period for both migration and breeding time and was positively correlated to winter/spring climate, i.e. selection was stronger after warmer winters/springs. However, the increasing selection pressure on timing seems to be unrelated to climate change as the climatic variables that were related to selection strength did not increase during the study period. There is indirect evidence that phenology or abundances of preferred prey species have changed which could have altered selection on timing of migration and breeding.

  14. Nesting Bird “Host Funnel” Increases Mosquito-Bird Contact Rate

    OpenAIRE

    CAILLOUËT, KEVIN A.; RIGGAN, ANNA E.; BULLUCK, LESLEY P.; CARLSON, JOHN C.; SABO, ROY T.

    2013-01-01

    Increases in vector-host contact rates can enhance arbovirus transmission intensity. We investigated weekly fluctuations in contact rates between mosquitoes and nesting birds using the recently described Nest Mosquito Trap (NMT). The number of mosquitoes per nestling increased from < 1 mosquito per trap night to 36.2 in the final 2 wk of the nesting season. Our evidence suggests the coincidence of the end of the avian nesting season and increasing mosquito abundances may have caused a “host f...

  15. Rural-urban migration and urban unemployment in Nigeria.

    Science.gov (United States)

    Aigbokhan, B E

    1988-01-01

    This paper argues that urban unemployment in Nigeria has been due largely to a failure on the part of the government to pursue policies that reflect commitment on its part to its stated objectives, particularly with regard to employment opportunities. Rural-urban migration has been taking place in the country since the 1960s and at an increasing rate since the 1970s. Economic policies have contributed to this, notably the rural-urban imbalance resulting from the pattern of allocation of public investment expenditures and the wages determination process which tends to concentrate more on the urban sector. These have contributed to the widening urban-rural income differentials. In the face of such migration, the urban industrial sector has been able to absorb only a negligible proportion of migrants. A major factor that has contributed to this is the increased capital-intensity of the sector. Some laudable measures have been introduced this year, notably the establishment of the Directorate of Employment and the Directorate of Food, Road, and Rural infrastructure. The latter, if effectively implemented, should enhance rural income and thereby reduce the rural-urban income gap. The former should reduce the problem of open unemployment. While it is too early to assess the effects of these 2 measures on urban unemployment, they may not improve urban unemployment significantly. There is still the need to design policies to increase labor absorption in general.

  16. How Has Elderly Migration Changed in the Twenty-First Century? What the Data Can-and Cannot-Tell Us.

    Science.gov (United States)

    Conway, Karen Smith; Rork, Jonathan C

    2016-08-01

    Interstate elderly migration has strong implications for state tax policies and health care systems, yet little is known about how it has changed in the twenty-first century. Its relative rarity requires a large data set with which to construct reliable measures, and the replacement of the U.S. Census long form (CLF) with the American Community Survey (ACS) has made such updates difficult. Two commonly used alternative migration data sources-the Current Population Survey (CPS) and the Statistics of Income (SOI) program of the Internal Revenue Service (IRS)-suffer serious limitations in studying the migration of any subpopulation, including the elderly. Our study informs migration research in the post-2000 era by identifying methodological differences between data sources and devising strategies for reconciling the CLF and ACS. Our investigation focusing on the elderly suggests that the ACS can generate comparable migration data that reveal a continuation of previously identified geographic patterns as well as changes unique to the 2000s. However, its changed definition of residence and survey timing leaves us unable to construct a comparable national migration rate, suggesting that one must use national trends in the smaller CPS to investigate whether elderly migration has increased or decreased in the twenty-first century.

  17. Increased degradation rate of nitrososureas in media containing carbonate.

    Science.gov (United States)

    Seidegård, Janeric; Grönquist, Lena; Tuvesson, Helen; Gunnarsson, Per-Olov

    2009-01-01

    The stability of two nitrosoureas, tauromustine and lomustine, has been investigated in different media and buffers. All media tested, except Leibovitz's L-15 medium, significantly increased the degradation rate of the investigated nitrosoureas at pH 7.4. Sodium bicarbonate seems to be the cause of the observed increase of the degradation rate, since it provides the main buffering capacity of all the media except for Leibovitz's L-15 medium, which is based on phosphate buffer. Other ingredients in the media, such as amino acids, vitamins, and inorganic salts, or the ionic strength of a buffer, did not have any major effect on the degradation rate of the nitrosoureas. These results suggest that media containing carbonated buffer should be avoided when the anti-tumor effect of nitrosoureas is to be investigated in different cell cultures.

  18. Holocene depocenter migration and sediment accumulation in Delaware Bay: A submerging marginal marine sedimentary basin

    Science.gov (United States)

    Fletcher, C. H.; Knebel, H.J.; Kraft, J.C.

    1992-01-01

    The Holocene transgression of the Delaware Bay estuary and adjacent Atlantic coast results from the combined effect of regional crustal subsidence and eustasy. Together, the estuary and ocean coast constitute a small sedimentary basin whose principal depocenter has migrated with the transgression. A millenial time series of isopach and paleogeographic reconstructions for the migrating depocenter outlines the basin-wide pattern of sediment distribution and accumulation. Upland sediments entering the basin through the estuarine turbidity maximum accumulate in tidal wetland or open water sedimentary environments. Wind-wave activity at the edge of the tidal wetlands erodes the aggraded Holocene section and builds migrating washover barriers. Along the Atlantic and estuary coasts of Delaware, the area of the upland environment decreases from 2.0 billion m2 to 730 million m2 during the transgression. The area of the tidal wetland environment increases from 140 million to 270 million m2, and due to the widening of the estuary the area of open water increases from 190 million to 1.21 billion m2. Gross uncorrected rates of sediment accumulation for the tidal wetlands decrease from 0.64 mm/yr at 6 ka to 0.48 mm/yr at 1 ka. In the open water environments uncorrected rates decrease from 0.50 mm/yr to 0.04 mm/yr over the same period. We also present data on total sediment volumes within the tidal wetland and open water environments at specific intervals during the Holocene. 

  19. Cohort Measures of Internal Migration: Understanding Long-Term Trends.

    Science.gov (United States)

    Bernard, Aude

    2017-12-01

    Internal migration intensities fluctuate over time, but both migration levels and trends show great diversity. The dynamics underpinning these trends remain poorly understood because they are analyzed almost exclusively by applying period measures to cross-sectional data. This article proposes 10 cohort measures that can be applied to both prospective and retrospective data to systematically examine long-term trends. To demonstrate their benefits, the proposed measures are applied to retrospective survey data for England that provide residential histories from birth to age 50 for cohorts born between 1918 and 1957. The analysis reveals stable lifetime migration for men but increased lifetime migration for women associated with earlier ages at moving in adulthood and a compression of intervals between consecutive moves. The proposed cohort measures provide a more comprehensive picture of migration behavior and should be used to complement period measures in exploring long-term trends. Increasing availability of retrospective and longitudinal survey data means that researchers can now apply the proposed measures to a wide range of countries.

  20. Migration, Development and Poverty Reduction in the Southern ...

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

    Since 1990, the number of people in the Southern African Development Community (SADC) crossing borders has increased dramatically. While people migrate for a variety of reasons, most do so as a livelihood strategy. Prior to the 1990s, labour migration was confined primarily to the mining sector. Today, commercial ...

  1. Bats on a Budget: Torpor-Assisted Migration Saves Time and Energy

    Science.gov (United States)

    McGuire, Liam P.; Jonasson, Kristin A.; Guglielmo, Christopher G.

    2014-01-01

    Bats and birds must balance time and energy budgets during migration. Migrating bats face similar physiological challenges to birds, but nocturnality creates special challenges for bats, such as a conflict between travelling and refueling, which many birds avoid by feeding in daylight and flying at night. As endothermic animals, bats and birds alike must expend substantial amounts of energy to maintain high body temperatures. For migratory birds refueling at stopovers, remaining euthermic during inactive periods reduces the net refuelling rate, thereby prolonging stopover duration and delaying subsequent movement. We hypothesized that bats could mitigate similar ambient-temperature dependent costs by using a torpor-assisted migration strategy. We studied silver-haired bats Lasionycteris noctivagans during autumn migration using a combination of respirometry and temperature-sensitive radiotelemetry to estimate energy costs incurred under ambient temperature conditions, and the energy that bats saved by using torpor during daytime roosting periods. All bats, regardless of sex, age, or body condition used torpor at stopover and saved up to 91% of the energy they would have expended to remain euthermic. Furthermore, bats modulated use of torpor depending on ambient temperature. By adjusting the time spent torpid, bats achieved a rate of energy expenditure independent of the ambient temperature encountered at stopover. By lowering body temperature during inactive periods, fuel stores are spared, reducing the need for refuelling. Optimal migration models consider trade-offs between time and energy. Heterothermy provides a physiological strategy that allows bats to conserve energy without paying a time penalty as they migrate. Although uncommon, some avian lineages are known to use heterothermy, and current theoretical models of migration may not be appropriate for these groups. We propose that thermoregulatory strategies should be an important consideration of future

  2. HGF and c-Met Interaction Promotes Migration in Human Chondrosarcoma Cells

    Science.gov (United States)

    Tsou, Hsi-Kai; Chen, Hsien-Te; Hung, Ya-Huey; Chang, Chia-Hao; Li, Te-Mao; Fong, Yi-Chin; Tang, Chih-Hsin

    2013-01-01

    Chondrosarcoma is a type of highly malignant tumor with a potent capacity for local invasion and causing distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. Hepatocyte growth factor (HGF) has been demonstrated to stimulate cancer proliferation, migration, and metastasis. However, the effect of HGF on migration activity of human chondrosarcoma cells is not well known. Here, we found that human chondrosarcoma tissues demonstrated significant expression of HGF, which was higher than that in normal cartilage. We also found that HGF increased the migration and expression of matrix metalloproteinase (MMP)-2 in human chondrosarcoma cells. c-Met inhibitor and siRNA reduced HGF-increased cell migration and MMP-2 expression. HGF treatment resulted in activation of the phosphatidylinositol 3′-kinase (PI3K)/Akt/PKCδ/NF-κB pathway, and HGF-induced expression of MMP-2 and cell migration was inhibited by specific inhibitors or siRNA-knockdown of PI3K, Akt, PKCδ, and NF-κB cascades. Taken together, our results indicated that HGF enhances migration of chondrosarcoma cells by increasing MMP-2 expression through the c-Met receptor/PI3K/Akt/PKCδ/NF-κB signal transduction pathway. PMID:23320110

  3. HGF and c-Met interaction promotes migration in human chondrosarcoma cells.

    Directory of Open Access Journals (Sweden)

    Hsi-Kai Tsou

    Full Text Available Chondrosarcoma is a type of highly malignant tumor with a potent capacity for local invasion and causing distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. Hepatocyte growth factor (HGF has been demonstrated to stimulate cancer proliferation, migration, and metastasis. However, the effect of HGF on migration activity of human chondrosarcoma cells is not well known. Here, we found that human chondrosarcoma tissues demonstrated significant expression of HGF, which was higher than that in normal cartilage. We also found that HGF increased the migration and expression of matrix metalloproteinase (MMP-2 in human chondrosarcoma cells. c-Met inhibitor and siRNA reduced HGF-increased cell migration and MMP-2 expression. HGF treatment resulted in activation of the phosphatidylinositol 3'-kinase (PI3K/Akt/PKCδ/NF-κB pathway, and HGF-induced expression of MMP-2 and cell migration was inhibited by specific inhibitors or siRNA-knockdown of PI3K, Akt, PKCδ, and NF-κB cascades. Taken together, our results indicated that HGF enhances migration of chondrosarcoma cells by increasing MMP-2 expression through the c-Met receptor/PI3K/Akt/PKCδ/NF-κB signal transduction pathway.

  4. Landbird migration in the American West: Recent progress and future research directions

    Science.gov (United States)

    Carlisle, J.D.; Skagen, S.K.; Kus, B.E.; van Riper, Charles; Paxton, K.L.; Kelly, J.F.

    2009-01-01

    Our knowledge of avian behaviors during the nonbreeding period still lags behind that of the breeding season, but the last decade has witnessed a proliferation in research that has yielded significant progress in understanding migration patterns of North American birds. And, although historically the great majority of migration research has been conducted in the eastern half of the continent, there has been much recent progress on aspects of avian migration in the West. In particular, expanded use of techniques such as radar, plasma metabolites, mist-netting, count surveys, stable isotopes, genetic data, and animal tracking, coupled with an increase in multi-investigator collaborations, have all contributed to this growth of knowledge. There is increasing recognition that migration is likely the most limiting time of year for migratory birds, increasing the importance of continuing to decipher patterns of stopover ecology, identifying critical stopover habitats, and documenting migration routes in the diverse and changing landscapes of the American West. Here, we review and briefly synthesize the latest findings and advances in avian migration and consider research needs to guide future research on migration in the West. ?? 2009 by The Cooper Ornithological Society. All rights reserved.

  5. Outward Migration of Giant Planets in Orbital Resonance

    Science.gov (United States)

    D'Angelo, G.; Marzari, F.

    2013-05-01

    A pair of giant planets interacting with a gaseous disk may be subject to convergent orbital migration and become locked into a mean motion resonance. If the orbits are close enough, the tidal gaps produced by the planets in the disk may overlap. This represents a necessary condition to activate the outward migration of the pair. However, a number of other conditions must also be realized in order for this mechanism to operate. We have studied how disk properties, such as turbulence viscosity, temperature, surface density gradient, mass, and age, may affect the outcome of the outward migration process. We have also investigated the implications on this mechanism of the planets' gas accretion. If the pair resembles Jupiter and Saturn, the 3:2 orbital resonance may drive them outward until they reach stalling radii for migration, which are within ~10 AU of the star for disks representative of the early proto-solar nebula. However, planet post-formation conditions in the disk indicate that such planets become typically locked in the 1:2 orbital resonance, which does not lead to outward migration. Planet growth via gas accretion tends to alter the planets' mass-ratio and/or the disk accretion rate toward the star, reducing or inhibiting outward migration. Support from NASA Outer Planets Research Program and NASA Origins of Solar Systems Program is gratefully acknowledged.

  6. Environmental risk, resilience and migration: implications for natural resource management and agriculture

    International Nuclear Information System (INIS)

    Deshingkar, Priya

    2012-01-01

    This letter probes the causal links between migration, remittances and resilience to environmental change. Three case studies have been chosen, Western Mexico, the Central Plateau of Burkina Faso and Eastern India, where satellite imagery shows recent regeneration of vegetative cover and where there is evidence of high rates of migration. The findings are analysed through a framework that draws on concepts of ecological anthropology, new economics of labour theories and livelihood analyses of migration drivers and impacts. (letter)

  7. Evaluation of radionuclide migration in the homogeneous system of a geological repository

    International Nuclear Information System (INIS)

    Prvakova, S.; Duran, J.; Necas, V.

    2005-01-01

    The aim of this paper is to study radionuclide migration and release from a deep underground repository situated in a clay formation. An insight into the processes influencing the radionuclide transport in the near field and far field will be presented. For the calculation, a set of radionuclides has been chosen, considering the half-life, decay chains, capacity of the sorption, solubility limits and diffusion coefficients. The migration of radionuclides is dependent on transport properties of the particular nuclide. Due to the low hydraulic conductivity of the backfill material and clay geological formation, the transport in the repository occurs mainly by diffusion. The migration rate will be influenced by the water chemistry, solubility, retardation and diffusive properties of the nuclides, and the water flow rate in the clay. The release rates of radionuclides from the geosphere to the biosphere will be converted into the indicative dose rates using dose conversion factors for ingestion. The impact of the critical group is considered via consumption of meat, root vegetables and drinking water from wells. (author)

  8. Radon depth migration

    International Nuclear Information System (INIS)

    Hildebrand, S.T.; Carroll, R.J.

    1993-01-01

    A depth migration method is presented that used Radon-transformed common-source seismograms as input. It is shown that the Radon depth migration method can be extended to spatially varying velocity depth models by using asymptotic ray theory (ART) to construct wavefield continuation operators. These operators downward continue an incident receiver-array plane wave and an assumed point-source wavefield into the subsurface. The migration velocity model is constrain to have longer characteristic wavelengths than the dominant source wavelength such that the ART approximations for the continuation operators are valid. This method is used successfully to migrate two synthetic data examples: (1) a point diffractor, and (2) a dipping layer and syncline interface model. It is shown that the Radon migration method has a computational advantage over the standard Kirchhoff migration method in that fewer rays are computed in a main memory implementation

  9. Chemical speciation of radionuclides migrating in groundwaters

    International Nuclear Information System (INIS)

    Robertson, D.; Schilk, A.; Abel, K.; Lepel, E.; Thomas, C.; Pratt, S.; Cooper, E.; Hartwig, P.; Killey, R.

    1994-04-01

    In order to more accurately predict the rates and mechanisms of radionuclide migration from low-level waste disposal facilities via groundwater transport, ongoing studies are being conducted at field sites at Chalk River Laboratories to identify and characterize the chemical speciation of mobile, long-lived radionuclides migrating in groundwaters. Large-volume water sampling techniques are being utilized to separate and concentrate radionuclides into particular, cationic, anionic, and nonionic chemical forms. Most radionuclides are migrating as soluble, anionic species that appear to be predominantly organoradionuclide complexes. Laboratory studies utilizing anion exchange chromatography have separated several anionically complexed radionuclides, e.g., 60 Co and 106 Ru, into a number of specific compounds or groups of compounds. Further identification of the anionic organoradionuclide complexes is planned utilizing high resolution mass spectrometry. Large-volume ultra-filtration experiments are characterizing the particulate forms of radionuclides being transported in these groundwaters

  10. [International migration and income redistribution: a trade-theoretic analysis].

    Science.gov (United States)

    Leiner, N; Meckl, J

    1995-05-01

    "We analyze the income-redistribution effects of international migration in the host and source country in a general equilibrium framework. The well-known result that marginal migration leaves the welfare of nonmigrants unaffected is discussed in more detail with regard to shifts in national income distributions. With endogenous goods' prices the consequences for the income distribution are in general ambiguous--we show possibilities for an estimation of their magnitude. As long as wage disparities determine the direction of migration it increases world efficiency. However, redistributive policies may generate migration towards the low-wage country." (SUMMARY IN ENG) excerpt

  11. ASIC proteins regulate smooth muscle cell migration.

    Science.gov (United States)

    Grifoni, Samira C; Jernigan, Nikki L; Hamilton, Gina; Drummond, Heather A

    2008-03-01

    The purpose of the present study was to investigate Acid Sensing Ion Channel (ASIC) protein expression and importance in cellular migration. We recently demonstrated that Epithelial Na(+)Channel (ENaC) proteins are required for vascular smooth muscle cell (VSMC) migration; however, the role of the closely related ASIC proteins has not been addressed. We used RT-PCR and immunolabeling to determine expression of ASIC1, ASIC2, ASIC3 and ASIC4 in A10 cells. We used small interference RNA to silence individual ASIC expression and determine the importance of ASIC proteins in wound healing and chemotaxis (PDGF-bb)-initiated migration. We found ASIC1, ASIC2, and ASIC3, but not ASIC4, expression in A10 cells. ASIC1, ASIC2, and ASIC3 siRNA molecules significantly suppressed expression of their respective proteins compared to non-targeting siRNA (RISC) transfected controls by 63%, 44%, and 55%, respectively. Wound healing was inhibited by 10, 20, and 26% compared to RISC controls following suppression of ASIC1, ASIC2, and ASIC3, respectively. Chemotactic migration was inhibited by 30% and 45%, respectively, following suppression of ASIC1 and ASIC3. ASIC2 suppression produced a small, but significant, increase in chemotactic migration (4%). Our data indicate that ASIC expression is required for normal migration and may suggest a novel role for ASIC proteins in cellular migration.

  12. Internal migration, regional labor markets and the role of agglomeration economies

    DEFF Research Database (Denmark)

    Mitze, Timo Friedel; Schmidt, Torben Dall

    2015-01-01

    are indeed key drivers of internal migration flows in Denmark. That is, while we obtain mixed evidence with regard to the role of traditional labor and housing market variables, most of the included proxies for agglomeration economies such as the region’s population density, patent intensity, endowment......We analyze the determinants and regional implications of internal migration flows across Danish municipalities in 2006–2012. Besides assessing the role of labor market and housing market factors in driving a region’s net migration rate, we particularly focus on agglomeration factors identified...... for the role of space–time dynamic adjustment processes and simultaneity among migration and labor market variables and finally test for heterogeneity in the migration response to regional labor market disparities among low- and high-skilled migrants. Our results support the view that agglomeration economies...

  13. 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.

  14. THE IMPACT OF AGRICULTURAL PRODUCTIVITY ON RURAL TO URBAN MIGRATION IN JAVA, INDONESIA

    Directory of Open Access Journals (Sweden)

    Renata Fauzia

    2013-11-01

    Full Text Available This paper investigates if the improvement of agricultural productivity will decrease rural to urban migration. Since rural to urban migration occurs due mainly to disparity between urban and agricultural wage, we assume that boosting agricultural income will reduce migration to urban areas. It is hypothesized that increase in agricultural productivity would result in a rise in agricultural wage, and hence income, ceteris paribus, reduces rural-urban migration. The data used in this study is the 2010 provincial statistics in West Java, Central Java, and East Java, Indonesia. The agricultural productivity and migration equations were estimated by using Ordinary Least Squares (OLS. The research findings may offer the suggestion to reduce rural to urban migration by boosting rural income through focusing the policy on agricultural productivity. Enhancing investment in agricultural sector such as increasing the number of subsidized fertilizer, adding agricultural labor and livestock, increasing education of rural people, and utilizing agricultural land resource are expected to increase agricultural output.Thus, it would also minimize the wage differential between urban and rural area.

  15. Gender, migration, risky sex, and HIV infection in China.

    Science.gov (United States)

    Yang, Xiushi; Xia, Guomei

    2006-12-01

    Gender differences in sexual behavior as a consequence of migration have been ignored in both the migration and the HIV literature in China. This study examines differences among temporary migrants in terms of sexual behavior and factors that make female migrants more vulnerable to the risk of acquiring HIV infection. Results suggest that the interplay of migration and gender renders female temporary migrants particularly vulnerable to engaging in casual and commercial sex. Although male temporary migrants do not differ from male nonmigrants in prevalence of casual and commercial sex, the prevalence rates of casual and commercial sex for female temporary migrants are found to be 14 and 80 times those for female nonmigrants, respectively. Female temporary migrants' higher unemployment rate and concentration in the service and entertainment sectors are keys to understanding differences in the prevalence of casual and commercial sex among temporary migrants according to sex. Policy measures to promote female temporary migrants' equal access to employment are urgently needed to improve their economic well-being and to reduce their risky sexual behavior.

  16. Does migration matter? Job search outcomes for the unemployed.

    Science.gov (United States)

    Boehm, T P; Herzog, H W; Schlottmann, A M

    1998-01-01

    The US has long been characterized by its geographically mobile population, with workers historically seeking new or better jobs in different locales as dictated by either opportunity or necessity. It is now generally accepted that the main determinants of interregional labor force migration are differential employment growth and amenity-adjusted earnings. The authors investigate migration's effect upon labor market transitions. Specifically, transition rates out of unemployment to employment, and from nonparticipation to active job search are examined. A multistate model of the hazard rate is developed and estimated to facilitate this process. Study results strongly suggest that migration is both directly and indirectly associated with a successful transition to re-employment. Findings are based upon the analysis of longitudinal microdata drawn from the corrected 1987 panel of the Survey of Income and Program Participation. Monthly labor market histories used covered the period from January 1987 to March 1989, for a research population of 3814 heads of households involved in 6096 total months of employment, job searching, and nonparticipation over the 26-month study period.

  17. 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.

  18. Parenting from Abroad: Migration, Nonresident Father Involvement, and Children's Education in Mexico

    Science.gov (United States)

    Nobles, Jenna

    2011-01-01

    In Mexico, a country with high emigration rates, parental migration matches divorce as a contributor to child-father separation. Yet little has been written about children's relationships with migrating parents. In this study, I use nationally representative data from the 2005 Mexican Family Life Survey to model variation in the interaction…

  19. Neuronal Migration and Neuronal Migration Disorder in Cerebral Cortex

    OpenAIRE

    SUN, Xue-Zhi; TAKAHASHI, Sentaro; GUI, Chun; ZHANG, Rui; KOGA, Kazuo; NOUYE, Minoru; MURATA, Yoshiharu

    2002-01-01

    Neuronal cell migration is one of the most significant features during cortical development. After final mitosis, neurons migrate from the ventricular zone into the cortical plate, and then establish neuronal lamina and settle onto the outermost layer, forming an "inside-out" gradient of maturation. Neuronal migration is guided by radial glial fibers and also needs proper receptors, ligands, and other unknown extracellular factors, requests local signaling (e.g. some emitted by the Cajal-Retz...

  20. 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…

  1. 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.

  2. IDENTIFICATION OF MAIN ECONOMIC AND SOCIAL CAUSES OF ROMANIAN MIGRATION

    Directory of Open Access Journals (Sweden)

    Elena Raluca CRISTIAN

    2015-07-01

    Full Text Available The main worldwide determinants influencing in time the migration phenomenon are: external environment (international political situation, economy, population growth in the migrant’s country, armed conflicts, religious persecution and xenophobic attacks. The migration of manpower from Romania is based on a number of psychological, social, financial reasons of migrants to increase their income and improve their living conditions in another country. The main cause of migration in developed countries is the migration flows originating mainly from poor or very poor countries considered disadvantaged.

  3. Migration of rice planthoppers and their vectored re-emerging and novel rice viruses in East Asia.

    Science.gov (United States)

    Otuka, Akira

    2013-10-28

    This review examines recent studies of the migration of three rice planthoppers, Laodelphax striatellus, Sogatella furcifera, and Nilaparvata lugens, in East Asia. Laodelphax striatellus has recently broken out in Jiangsu province, eastern China. The population density in the province started to increase in the early 2000s and peaked in 2004. In 2005, Rice stripe virus (RSV) viruliferous rate of L. striatellus peaked at 31.3%. Since then, rice stripe disease spread severely across the whole province. Due to the migration of the RSV vectors, the rice stripe disease spread to neighboring countries Japan and Korea. An overseas migration of L. striatellus that occurred in 2008 was analyzed, when a slow-moving cold vortex, a type of low pressure system, reached western Japan from Jiangsu, carrying the insects into Japan. Subsequently the rice stripe diseases struck these areas in Japan severely. In Korea, similar situations occurred in 2009, 2011, and 2012. Their migration sources were also estimated to be in Jiangsu by backward trajectory analysis. Rice black-streaked dwarf virus, whose vector is L. striatellus, has recently re-emerged in eastern China, and the evidence for overseas migrations of the virus, just like the RSV's migrations, has been given. A method of predicting the overseas migration of L. striatellus has been developed by Japanese, Chinese, and Korean institutes. An evaluation of the prediction showed that this method properly predicted migration events that occurred in East Asia from 2008 to 2011. Southern rice black-streaked dwarf virus (SRBSDV) was first found in Guangdong province. Its vector is S. furcifera. An outbreak of SRBSDV occurred in southern China in 2009 and spread to Vietnam the same year. This disease and virus were also found in Japan in 2010. The epidemic triggered many migration studies to investigate concrete spring-summer migration routes in China, and the addition of migration sources for early arrivals in Guangdong and Guangxi

  4. [Internal migration studies].

    Science.gov (United States)

    Stpiczynski, T

    1986-10-01

    Recent research on internal migration in Poland is reviewed. The basic sources of data, consisting of censuses or surveys, are first described. The author discusses the relationship between migration studies and other sectors of the national economy, and particularly the relationship between migration and income.

  5. The apparent and effective chloride migration coefficients obtained in migration tests

    NARCIS (Netherlands)

    Spiesz, P.R.; Brouwers, H.J.H.

    2013-01-01

    The apparent (Dapp) and effective (Deff) migration coefficients obtained in chloride migration tests are investigated in this study. The presented Dapp profiles in concrete show that the apparent migration coefficient is strongly concentration-dependent. As demonstrated, the binding of chlorides is

  6. Determinants of spring migration departure decision in a bat.

    Science.gov (United States)

    Dechmann, Dina K N; Wikelski, M; Ellis-Soto, D; Safi, K; O'Mara, M Teague

    2017-09-01

    Migratory decisions in birds are closely tied to environmental cues and fat stores, but it remains unknown if the same variables trigger bat migration. To learn more about the rare phenomenon of bat migration, we studied departure decisions of female common noctules ( Nyctalus noctula ) in southern Germany. We did not find the fattening period that modulates departure decisions in birds. Female noctules departed after a regular evening foraging session, uniformly heading northeast. As the day of year increased, migratory decisions were based on the interactions among wind speed, wind direction and air pressure. As the migration season progressed, bats were likely to migrate on nights with higher air pressure and faster tail winds in the direction of travel, and also show high probability of migration on low-pressure nights with slow head winds. Common noctules thus monitor complex environmental conditions to find the optimal migration night. © 2017 The Authors.

  7. Effect of solute concentration on grain boundary migration with segregation in stainless steel and model alloys

    Science.gov (United States)

    Kanda, H.; Hashimoto, N.; Takahashi, H.

    The phenomenon of grain boundary migration due to boundary diffusion via vacancies is a well-known process for recrystallization and grain growth during annealing. This phenomenon is known as diffusion-induced grain boundary migration (DIGM) and has been recognized in various binary systems. On the other hand, grain boundary migration often occurs under irradiation. Furthermore, such radiation-induced grain boundary migration (RIGM) gives rise to solute segregation. In order to investigate the RIGM mechanism and the interaction between solutes and point defects during the migration, stainless steel and Ni-Si model alloys were electron-irradiated using a HVEM. RIGM was often observed in stainless steels during irradiation. The migration rate of boundary varied, and three stages of the migration were recognized. At lower temperatures, incubation periods up to the occurrence of the boundary migration were observed prior to first stage. These behaviors were recognized particularly for lower solute containing alloys. From the relation between the migration rates at stage I and inverse temperatures, activation energies for the boundary migration were estimated. In comparison to the activation energy without irradiation, these values were very low. This suggests that the RIGM is caused by the flow of mixed-dumbbells toward the grain boundary. The interaction between solute and point defects and the effective defect concentration generating segregation will be discussed.

  8. Dunes on planet Tatooine: Observation of barchan migration at the Star Wars film set in Tunisia

    Science.gov (United States)

    Lorenz, Ralph D.; Gasmi, Nabil; Radebaugh, Jani; Barnes, Jason W.; Ori, Gian G.

    2013-11-01

    Sand dune migration is documented with a readily-available tool (Google Earth) near Chott El Gharsa, just north-west of Tozeur, Tunisia. As fiducial markers we employ a set of buildings used to portray the fictional city Mos Espa. This set of ~ 20 buildings over roughly a hectare was constructed in 1997 for the movie Star Wars Episode 1 - The Phantom Menace. The site now lies between the arms of a large “pudgy” barchan dune, which has been documented via satellite imaging in 2002, 2004, 2008 and 2009 to have moved from ~ 140 m away to only ~ 10 m away. Visits by the authors to the site in 2009 and 2011 confirm the barchan to be in a threatening position: a smaller set nearby was substantially damaged by being overrun by dunes circa 2004. The migration rate of ~ 15 m/yr decreases over the observation period, possibly as a result of increased local rainfall, and is consistent with barchan migration rates observed at other locations worldwide. The migration rate of this and two other barchans suggests sand transport of ~ 50 m3/m/yr, somewhat higher than would be suggested by traditional wind rose calculations: we explore possible reasons for this discrepancy. Because of the link to popular science fiction, the site may be of pedagogical interest in teaching remote sensing and geomorphic change. We also note that nearby playa surfaces and agricultural areas have a time-variable appearance. The site's popularity as a destination for Star Wars enthusiasts results in many photographs being posted on the internet, providing a rich set of in-situ imagery for continued monitoring in the absence of dedicated field visits.

  9. Multistate modelling extended by behavioural rules: An application to migration.

    Science.gov (United States)

    Klabunde, Anna; Zinn, Sabine; Willekens, Frans; Leuchter, Matthias

    2017-10-01

    We propose to extend demographic multistate models by adding a behavioural element: behavioural rules explain intentions and thus transitions. Our framework is inspired by the Theory of Planned Behaviour. We exemplify our approach with a model of migration from Senegal to France. Model parameters are determined using empirical data where available. Parameters for which no empirical correspondence exists are determined by calibration. Age- and period-specific migration rates are used for model validation. Our approach adds to the toolkit of demographic projection by allowing for shocks and social influence, which alter behaviour in non-linear ways, while sticking to the general framework of multistate modelling. Our simulations yield that higher income growth in Senegal leads to higher emigration rates in the medium term, while a decrease in fertility yields lower emigration rates.

  10. Examining the physical meaning of the bank erosion coefficient used in meander migration modeling

    Science.gov (United States)

    Constantine, Candice R.; Dunne, Thomas; Hanson, Gregory J.

    2009-05-01

    Widely used models of meander evolution relate migration rate to vertically averaged near-bank velocity through the use of a coefficient of bank erosion ( E). In applications to floodplain management problems, E is typically determined through calibration to historical planform changes, and thus its physical meaning remains unclear. This study attempts to clarify the extent to which E depends on measurable physical characteristics of the channel boundary materials using data from the Sacramento River, California, USA. Bend-average values of E were calculated from measured long-term migration rates and computed near-bank velocities. In the field, unvegetated bank material resistance to fluvial shear ( k) was measured for four cohesive and noncohesive bank types using a jet-test device. At a small set of bends for which both E and k were obtained, we discovered that variability in k explains much of the variability in E. The form of this relationship suggests that when modeling long-term meander migration of large rivers, E depends largely on bank material properties. This finding opens up the possibility that E may be estimated directly from field data, enabling prediction of meander migration rates for systems where historical data are unavailable or controlling conditions have changed. Another implication is that vegetation plays a limited role in affecting long-term meander migration rates of large rivers like the Sacramento River. These hypotheses require further testing with data sets from other large rivers.

  11. PVC cling film in contact with cheese: health aspects related to global migration and specific migration of DEHA

    DEFF Research Database (Denmark)

    Petersen, Jens Højslev; Naamansen, Ebbe Tubæk; Nielsen, Preben Aagård

    1995-01-01

    experiment samples of cheese of the types most commonly consumed in Denmark were wrapped in this 'low migration' PVC film using a procedure simulating the actual pattern of use in retail shops. After a storage time of 2 h at 5 degrees C the level of DEHA was 45 mg/kg of cheese, which after 10 days increased...... of DEHA close to or above the tolerable daily intake of 0.3 mg/kg body weight as defined by the EEC Scientific Committee for Food. Furthermore, it is stressed that measurements of global migration followed by uncritical use of reduction factors may result in erroneous evaluation of the suitability of DEHA-plasticized......Following exposure to the food simulant olive oil for 10 days at 5, 20 or 40 degrees C a global migration ranging from 20 to 30 mg/dm(2) was detected from a common 'low migration' PVC film plasticized with a mixture of di-(ethylhexyl)adipate (DEHA) and a polymeric plasticizer. In a laboratory...

  12. Stable and efficient Q-compensated least-squares migration with compressive sensing, sparsity-promoting, and preconditioning

    Science.gov (United States)

    Chai, Xintao; Wang, Shangxu; Tang, Genyang; Meng, Xiangcui

    2017-10-01

    The anelastic effects of subsurface media decrease the amplitude and distort the phase of propagating wave. These effects, also referred to as the earth's Q filtering effects, diminish seismic resolution. Ignoring anelastic effects during seismic imaging process generates an image with reduced amplitude and incorrect position of reflectors, especially for highly absorptive media. The numerical instability and the expensive computational cost are major concerns when compensating for anelastic effects during migration. We propose a stable and efficient Q-compensated imaging methodology with compressive sensing, sparsity-promoting, and preconditioning. The stability is achieved by using the Born operator for forward modeling and the adjoint operator for back propagating the residual wavefields. Constructing the attenuation-compensated operators by reversing the sign of attenuation operator is avoided. The method proposed is always stable. To reduce the computational cost that is proportional to the number of wave-equation to be solved (thereby the number of frequencies, source experiments, and iterations), we first subsample over both frequencies and source experiments. We mitigate the artifacts caused by the dimensionality reduction via promoting sparsity of the imaging solutions. We further employ depth- and Q-preconditioning operators to accelerate the convergence rate of iterative migration. We adopt a relatively simple linearized Bregman method to solve the sparsity-promoting imaging problem. Singular value decomposition analysis of the forward operator reveals that attenuation increases the condition number of migration operator, making the imaging problem more ill-conditioned. The visco-acoustic imaging problem converges slower than the acoustic case. The stronger the attenuation, the slower the convergence rate. The preconditioning strategy evidently decreases the condition number of migration operator, which makes the imaging problem less ill-conditioned and

  13. 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

  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. Reinventing US Internal Migration Studies in the Age of International Migration.

    Science.gov (United States)

    Ellis, Mark

    2012-03-01

    I argue that researchers have sidelined attention to issues raised by US internal migration as they shifted focus to the questions posed by the post-1960s rise in US immigration. In this paper, I offer some reasons about why immigration has garnered more attention and why there needs to be greater consideration of US internal migration and its significant and myriad social, economic, political, and cultural impacts. I offer three ideas for motivating more research into US internal geographic mobility that would foreground its empirical and conceptual connections to international migration. First, there should be more work on linked migration systems investigating the connections between internal and international flows. Second, the questions asked about immigrant social, cultural, and economic impacts and adaptations in host societies should also be asked about internal migrants. Third, and more generally, migration researchers should jettison the assumption that the national scale is the pre-eminent delimiter of migration types and processes. Some groups can move easily across borders; others are constrained in their moves within countries. These subnational scales and constraints will become more visible if migration research decentres the national from its theory and empirics.

  16. MANAGING MIGRATION: TURKISH PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    İhsan GÜLAY

    2018-04-01

    Full Text Available Conducting migration studies is of vital importance to Turkey, a country which has been experiencing migration throughout history due to its “open doors policy”. The objective of this study is to evaluate the strategic management of migration in Turkey in order to deal with the issue of migration. The main focus of the study is Syrian migrants who sought refuge in Turkey due to the civil war that broke out in their country in April 2011. This study demonstrates the policies and processes followed by Turkey for Syrian migration flow in terms of the social acceptance and harmonisation of the migrants within a democratic environment. The study addresses some statistical facts and issues related to Syrian migration as it has become an integral part of daily life in Turkey. The study also reviews how human rights are protected in the migration process. The study will provide insights for developing sound strategic management policies for the migration issue.

  17. Characteristics of meniscus progenitor cells migrated from injured meniscus.

    Science.gov (United States)

    Seol, Dongrim; Zhou, Cheng; Brouillette, Marc J; Song, Ino; Yu, Yin; Choe, Hyeong Hun; Lehman, Abigail D; Jang, Kee W; Fredericks, Douglas C; Laughlin, Barbara J; Martin, James A

    2017-09-01

    Serious meniscus injuries seldom heal and increase the risk for knee osteoarthritis; thus, there is a need to develop new reparative therapies. In that regard, stimulating tissue regeneration by autologous stem/progenitor cells has emerged as a promising new strategy. We showed previously that migratory chondrogenic progenitor cells (CPCs) were recruited to injured cartilage, where they showed a capability in situ tissue repair. Here, we tested the hypothesis that the meniscus contains a similar population of regenerative cells. Explant studies revealed that migrating cells were mainly confined to the red zone in normal menisci: However, these cells were capable of repopulating defects made in the white zone. In vivo, migrating cell numbers increased dramatically in damaged meniscus. Relative to non-migrating meniscus cells, migrating cells were more clonogenic, overexpressed progenitor cell markers, and included a larger side population. Gene expression profiling showed that the migrating population was more similar to CPCs than other meniscus cells. Finally, migrating cells equaled CPCs in chondrogenic potential, indicating a capacity for repair of the cartilaginous white zone of the meniscus. These findings demonstrate that, much as in articular cartilage, injuries to the meniscus mobilize an intrinsic progenitor cell population with strong reparative potential. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1966-1972, 2017. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  18. Satellite tracking of two Montagu's Harriers (Circus pygargus) : Dual pathways during autumn migration

    NARCIS (Netherlands)

    Trierweiler, Christiane; Koks, Ben J.; Drent, Rudi H.; Exo, Klaus-Michael; Komdeur, Jan; Dijkstra, Cor; Bairlein, Franz

    2007-01-01

    Autumn migration routes of two Dutch female Montagu's Harriers (Circus pygargus) were documented for the first time using satellite telemetry. Both migrated to their African wintering area-one via the Straits of Gibraltar through the Mediterranean and the other via Italy/Tunisia. The rate of travel

  19. The Implication Of Mens Rural-Urban Migration On Household Decision Making In Soy Sub-County Kenya

    Directory of Open Access Journals (Sweden)

    Lumayo Mildred Fedha

    2015-06-01

    Full Text Available Abstract While most regions in the world have been experiencing an increase in rural-urban migration some have experienced excessive rates. As mens rural-urban migration occurs one of the sectors that is mostly affected is the family institution where women take up the role of decision making in the household in their absence. This study is an outcome of the study conducted on the impact of rural-urban migration on household decision making in Soy sub-county. The study found that mens absence in the household affects different aspects within the family context. Mens rural-urban migration has led to an increase in the number of women-headed households in the rural areas. Women who are left in charge of households are expected to continue to perform their traditional roles at the same time taking on mens responsibilities within the household. However culture dictates that they consult men even when they are away. From a socio-cultural context mens prolonged absence has many implications on the family and community life and greatly affects institutions such as health education and agriculture. Therefore the presence of men is crucial to household security decision-making and mobility. The study recommends that as much as men are away from home women should be empowered to make household decisions for smooth running of household undertakings.

  20. State policies and internal migration in Asia.

    Science.gov (United States)

    Oberai, A S

    1981-01-01

    The objective of this discussion is to identify policies and programs in Asia that are explicitly or implicitly designed to influence migration, to investigate why they were adopted and how far they have actually been implemented, and to assess their direct and indirect consequences. For study purposes, policies and programs are classified according to whether they prohibit or reverse migration, redirect or channel migration to specific rural or urban locations, reduce the total volume of migration, or encourage or discourage urban in-migration. Discussion of each type of policy is accompanied by a description of its rationale and implementation mechanism, examples of countries in Asia that have recourse to it, and its intended or actual effect on migration. Several countries in Asia have taken direct measures to reverse the flow of migration and to stop or discourage migration to urban areas. These measures have included administrative and legal controls, police registration, and direct "rustication" programs to remove urban inhabitants to the countryside. The availability of public land has prompted many Asian countries to adopt schemes that have been labeled resettlement, transmigration, colonization, or land development. These schemes have been designed to realize 1 or more of the following objectives: to provide land and income to the landless; increase agricultural production; correct spatial imbalances in the distribution of population; or exploit frontier lands for reasons of national security. 1 of the basic goals of decentralized industrialization and regional development policies has been the reduction of interregional disparities and the redirection of migrations from large metropolitan areas to smaller and medium sized towns. To encourage industry to move to small urban locations initial infrastructure investments, tax benefits, and other incentives have been offered. Policies to reduce the overall volume of migration have frequently included rural

  1. 1,25(OH)2D3 attenuates TGF-β1/β2-induced increased migration and invasion via inhibiting epithelial–mesenchymal transition in colon cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shanwen; Zhu, Jing; Zuo, Shuai; Ma, Ju; Zhang, Junling; Chen, Guowei; Wang, Xin; Pan, Yisheng; Liu, Yucun; Wang, Pengyuan, E-mail: wangpengyuan2014@126.com

    2015-12-04

    1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) has been reported to inhibit proliferation and migration of multiple types of cancer cells. However, the mechanism underlying its anti-metastasis effect is not fully illustrated. In this study, the effect of 1,25(OH)2D3 on TGF-β1/β2-induced epithelial–mesenchymal transition (EMT) is tested in colon cancer cells. The results suggest that 1,25(OH)2D3 inhibited TGF-β1/β2-induced increased invasion and migration of in SW-480 and HT-29 cells. 1,25(OH)2D3 also inhibited the cadherin switch in SW-480 and HT-29 cells. TGF-β1/β2-induced increased expression of EMT-related transcription factors was also inhibited by 1,25(OH)2D3. 1,25(OH)2D3 also inhibited the secretion of MMP-2 and MMP-9 and increased expression of F-actin induced by TGF-β1/β2 in SW-480 cells. Taken together, this study suggests that the suppression of EMT might be one of the mechanisms underlying the anti-metastasis effect of 1,25(OH)2D3 in colon cancer cells. - Highlights: • TGF-β1/β2-induced model of EMT was used in this study to test the effect of 1,25(OH)2D3 on EMT in colon cancer cells. • 1,25(OH)2D3 inhibited TGF-β1/β2-induced increased migration and invasion. • 1,25(OH)2D3 inhibited TGF-β1/β2-induced increased level of EMT-related transcription factors. • 1,25(OH)2D3 inhibited TGF-β1/β2-induced increased expression of F-actin in SW-480 cells.

  2. THE DETERMINANTS OF INTERNAL MIGRATION: THE CASE OFTURKEY

    Directory of Open Access Journals (Sweden)

    Ciler Sigeze

    2016-07-01

    Full Text Available This study investigates the determinants of the net migration statistics at regionallevel-1, consisting 12 regions, according to the Nomenclature of Units forTerritorial Statistics (NUTS of Turkey during the period 2008-2014 utilizingFeasible Generalized Least Squares. The results show that the coefficient ofpoverty variable found negative as consistent with literature. This finding suggeststhat migration movements are still one of the important strategies against poverty.In the study, the amount of exports and electricity per person used as a proxy forthe level of development of the regions foundsignificant and positive on the netmigration rate of the region. This result shows that the level of development of aregion is related to the net migration of that region in the same direction.Therefore, policy makers should implement policies on internal migrationmovements todecrease differences in income inequality and development levelsbetween regions.

  3. Migration of methane into groundwater from leaking production wells near Lloydminster

    International Nuclear Information System (INIS)

    1995-03-01

    The problem of migration of methane from leaking oil and gas wells into aquifers in the Lloydminster area in Saskatchewan, was discussed. A study was conducted to determine if the methane in shallow aquifers near the leaking wells, came from the wells or occurred naturally. Migration rate in aquifers, concentration gradients and approximate flux rates of methane from leaking wells to shallow aquifers, were studied. The methods of investigation included drilling of test holes at selected sites, installation of monitoring wells, purging of wells, pumping tests and water level monitoring, sampling and analyses for dissolved methane. The relatively high methane concentrations in many of the monitoring wells indicated the presence of a methane plume that has migrated from the production well. It was suggested that other leaky well sites in the area should be investigated to determine if similar plumes were present. 18 refs., 5 tabs., 13 figs

  4. Coastal wetland adaptation to sea level rise: Quantifying potential for landward migration and coastal squeeze

    Science.gov (United States)

    Borchert, Sinéad M.; Osland, Michael J.; Enwright, Nicholas M.; Griffith, Kereen

    2018-01-01

    Coastal wetland ecosystems are expected to migrate landwards in response to rising seas. However, due to differences in topography and coastal urbanization, estuaries vary in their ability to accommodate migration. Low‐lying urban areas can constrain migration and lead to wetland loss (i.e. coastal squeeze), especially where existing wetlands cannot keep pace with rising seas via vertical adjustments. In many estuaries, there is a pressing need to identify landward migration corridors and better quantify the potential for landward migration and coastal squeeze.We quantified and compared the area available for landward migration of tidal saline wetlands and the area where urban development is expected to prevent migration for 39 estuaries along the wetland‐rich USA Gulf of Mexico coast. We did so under three sea level rise scenarios (0.5, 1.0, and 1.5 m by 2100).Within the region, the potential for wetland migration is highest within certain estuaries in Louisiana and southern Florida (e.g. Atchafalaya/Vermilion Bays, Mermentau River, Barataria Bay, and the North and South Ten Thousand Islands estuaries).The potential for coastal squeeze is highest in estuaries containing major metropolitan areas that extend into low‐lying lands. The Charlotte Harbor, Tampa Bay, and Crystal‐Pithlachascotee estuaries (Florida) have the highest amounts of urban land expected to constrain wetland migration. Urban barriers to migration are also high in the Galveston Bay (Texas) and Atchafalaya/Vermilion Bays (Louisiana) estuaries.Synthesis and applications. Coastal wetlands provide many ecosystem services that benefit human health and well‐being, including shoreline protection and fish and wildlife habitat. As the rate of sea level rise accelerates in response to climate change, coastal wetland resources could be lost in areas that lack space for landward migration. Migration corridors are particularly important in highly urbanized estuaries where, due to low‐lying coastal

  5. Comments in reply: new directions in migration research.

    Science.gov (United States)

    Shaw, R P

    1986-01-01

    The author comments on a review of his recent book NEW DIRECTIONS IN MIGRATION RESEARCH and reflects on theory and model specification, problems of estimation and statistical inference, realities of temporal and spatial heterogeneity, choices of explanatory variables, and the importance of broader political issues in migration studies. A core hypothesis is that market forces have declined as influences on internal migration in Canada over the last 30 years. Theoretical underpinnings include declining relevance of wage considerations in the decision to migrate on the assumption that marginal utility of money diminishes and marginal utility of leisure increases as society becomes wealthier. The author perceives the human capital model to have limitations and is especially troubled by the "as if" clause--that all migrants behave "as if" they calculate benefits and risks with equal rigor. The author has "shadowed" and not quantified the costs involved. He implies that normative frameworks for future migration research and planning should be established.

  6. Marriage, childbearing, and migration in Kyrgyzstan: Exploring interdependencies

    Directory of Open Access Journals (Sweden)

    Lesia Nedoluzhko

    2010-02-01

    Full Text Available In our study we investigate interdependencies between entry into a marital union, childbearing, and migration. We apply event-history techniques to retrospective data on women aged 18-29 from a survey conducted in northern Kyrgyzstan in 2005 to examine how these events can influence one another, with a special focus on the effects of duration of exposure. In addition we analyze the impact of some individual characteristics on the propensity to get married, to become a mother, and to migrate. In our analysis we account for several duration dependences ('clocks'. The results illustrate that months since marriage formation is the most important duration variable in the first-birth propensities model. Out-of-wedlock conception is associated with increased marriage risks. Migration is often a part of the family building process: high first-birth propensities of recent migrants as well as high migration risks among pregnant women are due to marriage-related migration.

  7. Changes in the specific migration characteristics of packaging-food simulant combinations caused by ionizing radiation: Effect of food simulant

    Science.gov (United States)

    Zygoura, Panagiota D.; Paleologos, Evangelos K.; Kontominas, Michael G.

    2011-08-01

    The primary objective of the present study was to evaluate the extent to which the affinity of the surrounding medium for the migrant, as well as the packaging material, affects the specific migration characteristics of the latter. For this purpose, migration tests were conducted with vinylidene chloride copolymer (PVDC/PVC) in contact with the EU specified solvents simulating all food types: namely, distilled water, 3% w/v acetic acid, 10% v/v ethanol and isooctane. Migration testing was carried out at 40 °C for 10 days for the aqueous simulants, and at 20 °C for 2 days for the fatty food simulant (EC, 1997; EEC, 1993). In addition, food-grade saran film was subjected to ionizing radiation treatment with a [60Co] source at doses equal to 5, 15 and 25 kGy. Acetyl tributyl citrate (ATBC) plasticizer levels were monitored as a function of time for untreated, as well as gamma-irradiated packaging material, with a secondary objective to investigate the effect of ionizing radiation on polymer/migrant/surrounding medium interactions. Depending on the food simulant, determination of the analyte was performed by either direct gas chromatographic analysis, or surfactant (Triton X-114) mediated extraction followed by gas chromatographic-flame ionization detection (GC-FID). ATBC concentrations determined in aqueous and fatty food simulants were 0.216-0.497 and 5.0-5.9 mg/L, respectively. Therefore, the most efficient extracting medium of plasticizers in vinyl chloride copolymers is the non-polar isooctane. Moreover, an extremely high rate of ATBC migration into isooctane during the early stages of contact was observed. The above observation verifies the aggressiveness of isooctane towards plastic packaging materials. Amongst the aqueous food simulants tested, the 10% ethanol solution demonstrated the highest migration levels. Gamma-irradiation enhanced ATBC migration; specific migration levels increased with increasing contact time and radiation dose. This was expected

  8. Changes in the specific migration characteristics of packaging-food simulant combinations caused by ionizing radiation: Effect of food simulant

    International Nuclear Information System (INIS)

    Zygoura, Panagiota D.; Paleologos, Evangelos K.; Kontominas, Michael G.

    2011-01-01

    The primary objective of the present study was to evaluate the extent to which the affinity of the surrounding medium for the migrant, as well as the packaging material, affects the specific migration characteristics of the latter. For this purpose, migration tests were conducted with vinylidene chloride copolymer (PVDC/PVC) in contact with the EU specified solvents simulating all food types: namely, distilled water, 3% w/v acetic acid, 10% v/v ethanol and isooctane. Migration testing was carried out at 40 o C for 10 days for the aqueous simulants, and at 20 o C for 2 days for the fatty food simulant (). In addition, food-grade saran film was subjected to ionizing radiation treatment with a [ 60 Co] source at doses equal to 5, 15 and 25 kGy. Acetyl tributyl citrate (ATBC) plasticizer levels were monitored as a function of time for untreated, as well as gamma-irradiated packaging material, with a secondary objective to investigate the effect of ionizing radiation on polymer/migrant/surrounding medium interactions. Depending on the food simulant, determination of the analyte was performed by either direct gas chromatographic analysis, or surfactant (Triton X-114) mediated extraction followed by gas chromatographic-flame ionization detection (GC-FID). ATBC concentrations determined in aqueous and fatty food simulants were 0.216-0.497 and 5.0-5.9 mg/L, respectively. Therefore, the most efficient extracting medium of plasticizers in vinyl chloride copolymers is the non-polar isooctane. Moreover, an extremely high rate of ATBC migration into isooctane during the early stages of contact was observed. The above observation verifies the aggressiveness of isooctane towards plastic packaging materials. Amongst the aqueous food simulants tested, the 10% ethanol solution demonstrated the highest migration levels. Gamma-irradiation enhanced ATBC migration; specific migration levels increased with increasing contact time and radiation dose. This was expected, since ATBC did not

  9. Changes in the specific migration characteristics of packaging-food simulant combinations caused by ionizing radiation: Effect of food simulant

    Energy Technology Data Exchange (ETDEWEB)

    Zygoura, Panagiota D., E-mail: me00806@cc.uoi.g [Laboratory of Food Chemistry and Technology, Department of Chemistry, University of Ioannina, GR-45110 Ioannina (Greece); Paleologos, Evangelos K.; Kontominas, Michael G. [Laboratory of Food Chemistry and Technology, Department of Chemistry, University of Ioannina, GR-45110 Ioannina (Greece)

    2011-08-15

    The primary objective of the present study was to evaluate the extent to which the affinity of the surrounding medium for the migrant, as well as the packaging material, affects the specific migration characteristics of the latter. For this purpose, migration tests were conducted with vinylidene chloride copolymer (PVDC/PVC) in contact with the EU specified solvents simulating all food types: namely, distilled water, 3% w/v acetic acid, 10% v/v ethanol and isooctane. Migration testing was carried out at 40 {sup o}C for 10 days for the aqueous simulants, and at 20 {sup o}C for 2 days for the fatty food simulant (). In addition, food-grade saran film was subjected to ionizing radiation treatment with a [{sup 60}Co] source at doses equal to 5, 15 and 25 kGy. Acetyl tributyl citrate (ATBC) plasticizer levels were monitored as a function of time for untreated, as well as gamma-irradiated packaging material, with a secondary objective to investigate the effect of ionizing radiation on polymer/migrant/surrounding medium interactions. Depending on the food simulant, determination of the analyte was performed by either direct gas chromatographic analysis, or surfactant (Triton X-114) mediated extraction followed by gas chromatographic-flame ionization detection (GC-FID). ATBC concentrations determined in aqueous and fatty food simulants were 0.216-0.497 and 5.0-5.9 mg/L, respectively. Therefore, the most efficient extracting medium of plasticizers in vinyl chloride copolymers is the non-polar isooctane. Moreover, an extremely high rate of ATBC migration into isooctane during the early stages of contact was observed. The above observation verifies the aggressiveness of isooctane towards plastic packaging materials. Amongst the aqueous food simulants tested, the 10% ethanol solution demonstrated the highest migration levels. Gamma-irradiation enhanced ATBC migration; specific migration levels increased with increasing contact time and radiation dose. This was expected, since

  10. Virtual machine migration in an over-committed cloud

    KAUST Repository

    Zhang, Xiangliang

    2012-04-01

    While early emphasis of Infrastructure as a Service (IaaS) clouds was on providing resource elasticity to end users, providers are increasingly interested in over-committing their resources to maximize the utilization and returns of their capital investments. In principle, over-committing resources hedges that users - on average - only need a small portion of their leased resources. When such hedge fails (i.e., resource demand far exceeds available physical capacity), providers must mitigate this provider-induced overload, typically by migrating virtual machines (VMs) to underutilized physical machines. Recent works on VM placement and migration assume the availability of target physical machines [1], [2]. However, in an over-committed cloud data center, this is not the case. VM migration can even trigger cascading overloads if performed haphazardly. In this paper, we design a new VM migration algorithm (called Scattered) that minimizes VM migrations in over-committed data centers. Compared to a traditional implementation, our algorithm can balance host utilization across all time epochs. Using real-world data traces from an enterprise cloud, we show that our migration algorithm reduces the risk of overload, minimizes the number of needed migrations, and has minimal impact on communication cost between VMs. © 2012 IEEE.

  11. Migration chemistry

    International Nuclear Information System (INIS)

    Carlsen, L.

    1992-05-01

    Migration chemistry, the influence of chemical -, biochemical - and physico-chemical reactions on the migration behaviour of pollutants in the environment, is an interplay between the actual natur of the pollutant and the characteristics of the environment, such as pH, redox conditions and organic matter content. The wide selection of possible pollutants in combination with varying geological media, as well as the operation of different chemical -, biochemical - and physico-chemical reactions compleactes the prediction of the influence of these processes on the mobility of pollutants. The report summarizes a wide range of potential pollutants in the terrestrial environment as well as a variety of chemical -, biochemical - and physico-chemical reactions, which can be expected to influence the migration behaviour, comprising diffusion, dispersion, convection, sorption/desorption, precipitation/dissolution, transformations/degradations, biochemical reactions and complex formation. The latter comprises the complexation of metal ions as well as non-polar organics to naturally occurring organic macromolecules. The influence of the single types of processes on the migration process is elucidated based on theoretical studies. The influence of chemical -, biochemical - and physico-chemical reactions on the migration behaviour is unambiguous, as the processes apparently control the transport of pollutants in the terrestrial environment. As the simple, conventional K D concept breaks down, it is suggested that the migration process should be described in terms of the alternative concepts chemical dispersion, average-elution-time and effective retention. (AB) (134 refs.)

  12. Labour migration and rural development in Egypt. A study of return migration in six villages.

    Science.gov (United States)

    Reichert, C

    1993-01-01

    An analysis of the impact of labor migration on social change in 6 rural villages (Shanawan and Kafr Shanawan north of Cairo, Kafr Yusuf and Tambul el Kubra near Simbalaween, and Abu Girg and Bani Walims in Minya governate) in Egypt was conducted in 1987-88. Since the 1991 Gulf war, the political environment, the labor markets, and the structure of migration opportunities have changed. An estimated 5% of rural households might have been directly affected by migrants' departure from Kuwait and Iraq. Data collection involved a household census survey of 8620 households, of which 2483 were migrants, including 1765 return migrants. A sample of return migrant (639) was interviewed about their migration experiences. Participant observation was also conducted among migrants and nonmigrants, and case studies were developed. Villages were demographically and socioeconomically very different; migration ranged from 18.5-434.2%. Structural change was measured on a scale of 1 to 6 in terms of population size, literacy of household heads, share of agricultural occupations, share of new red brick houses, and availability of infrastructural or institutional facilities. The probability of having a household with a migrant member increased with the rural character of the village. Landholdings or other major household variables were unrelated to migration. Rural outmigration was almost exclusively male, the average age was 29.6 years, and the average stay was 2.6 years. Migration destination was specific to individuals but affected by occupation and family or village resources. Professionals were overrepresented in Saudi Arabia, and farm and unskilled laborers or the unemployed were overrepresented in Iraq. Remittances from international migration have contributed along with the economic reforms of Sadat to new, private initiatives from all strata in rural society. 74.3% of returnees stated that improvement in income and living standards was the motivation for migration; many motives

  13. Basics elements for modelling the dynamics of cell migration in cell culture

    International Nuclear Information System (INIS)

    FarIas, Ro; Vidal, Cs; Rapacioli, M; Flores, V

    2007-01-01

    This paper introduces some basic elements for modelling the dynamics of cell migration activity over a bi-dimensional substratum. A square matrix, representing the substratum, is implemented in order to generate virtual cells with an initial random uniform distribution, with the ability to freely move within the matrix and to interact with each others by mean of adhesive forces. Two different conditions were examined: A) cells can freely move and after contacting with another cell they both completely inhibit their migration; B) cells that come into contact have the ability to rotate respect to each other without losing their contacts and retaining the ability to move together but at a slower rate, being the decrease in the rate of movement proportional to the number of contacting cells. The dynamics of the migration process in these two conditions was evaluated by recording the evolution of several parameters as a function of time. Minor modifications in some parameters (mobility, intensity of cell-cell and cell-substratum adhesiveness) significantly change the dynamics and the final result of the virtual migrating cells

  14. Selection or network effects? Migration flows into 27 OECD countries, 1990-2000

    DEFF Research Database (Denmark)

    Pedersen, Peder J.; Pytlikova, Mariola; Smith, Nina

    Recent migration patterns show growing migration pressure and changing composition of immigrants in many Western countries. During the latest decade, an increasing proportion of the OECD immigrants have been from poor countries, where the educational level of the population is low. The migration ...... evidence that selection effects have had a major influence on the observed migration patterns until now. This may partly be explained by restrictive migration policies in many OECD countries which may have dampened the potential selection effects....

  15. Selection or Network Effects? Migration Flows into 27 OECD Countries, 1990-2000

    DEFF Research Database (Denmark)

    Pedersen, P.J.; Pytlikova, Mariola; Smith, Nina

    Recent migration patterns show growing migration pressure and changing composition of immigrants in many Western countries. During the latest decade, an increasing proportion of the OECD immigrants have been from poor countries, where the educational level of the population is low. The migration ...... evidence that selection effects have had a major influence on the observed migration patterns until now. This may partly be explained by restrictive migration policies in many OECD countries which may have dampened the potential selection effects....

  16. Worker remittances, migration, accumulation and growth in poor developing countries

    OpenAIRE

    Ziesemer, T.H.W.

    2008-01-01

    The impact of migration and worker remittances on literacy, accumulation of capital and growth is analyzed for a panel of countries with per capita income below $1200 (2000). We estimate regressions for dynamic equations of migration, worker remittances, savings, investment, tax revenues, public expenditure on education, interest rates, literacy, labour force growth, development aid and GDP per capita growth, using dynamic panel data methods. The estimated equations are then integrated to a d...

  17. Temperature Changes, Household Consumption and Internal Migration: Evidence from Tanzania

    OpenAIRE

    Kalle Hirvonen

    2015-01-01

    Large rural-urban wage gaps observed in many developing countries are suggestive of barriers to migration that keep potential migrants in the rural areas. Using long panel data spanning nearly two decades, I study the extent to which migration rates are constrained by liquidity constraints in rural Tanzania. The analysis begins by quantifying the impact of weather variation on household welfare. The results show how household consumption co-moves with temperature rendering households vulnerab...

  18. Two types of population migration in China: a comparative study.

    Science.gov (United States)

    Gu, S

    1992-01-01

    The patterns, extent of, and trends in permanent and temporary migration in China are presented. Permanency is determined by a household registration transfer. Floaters are considered temporary migrants. The regulatory history of migration is given: restrictions prior to 1978 on temporary migration and relaxation of restrictions after 1978. Permanent migration was greatest in the 1950s. Between 1949 and 1960, there were 73.37 million permanent migrants to urban areas from rural areas out of an urban population increase of 105.83 million. During the 1960 and 1970s, urban population was lowered. During the Cultural Revolution, emigration surpassed immigration and the nonagricultural population increased in cities and towns. Between 1976 and 1987, the natural growth of the urban population declined, and nonagricultural population increased from 57.65 million to 204.057 million in cities and towns (1949-88). The trends in the floating population show the lowest ratio of temporary migrants to permanent migrants between 1984 and 1987 to be in Shenyang (15:100); the highest was in Guangzhou (33:100) with an average of 23:100. When the ratio is considered as 20:100 in cities, the average floating population is calculated at 52.87 million in 1987 out of 264.354 million total urban population. 70% were from rural areas. In a comparison of six provinces, Hebei had the lowest percentage of floaters (19%) and Shandong the highest (40%). In country-governed towns, and estimated temporary in-migrants numbered 9.48 million; 8/86 million were floaters. During peak migration, temporary migration averages 50 million/day and permanent migration averages 50,000/day. The primary difference between floaters and permanent migrants is that floaters keep their ties to the land. Surplus labor drives temporary migration, and as such is a release valve. Permanent migration, which is government-controlled, does not allow as much flexibility in adapting to socioeconomic conditions. The sectors

  19. MARKETING STRATEGY TO INCREASE BED OCCUPANCY RATE

    Directory of Open Access Journals (Sweden)

    Purwaningsih Purwaningsih

    2017-07-01

    Full Text Available Introduction: A hospital is an institution for health care providing treatment by specialized staff and equipment, more often but not always providing for longer-term patient stays. Today, hospitals are very complex institution, not only survive in dynamic environment but also make a profit based on their services. The aimed of this research was to know marketing mix concept (product, price, place, promotion, people, process and provision of customer service in formulating marketing strategy to increased Bed Occupancy Rate of Obstetric Gynecology Ward 2. Method: The population are health care personnel including midwife, midwife associate, administrator and also client or consumer. The variable were product, price, place, promotion, people, process and provision of customer service. Data were collected by using structured questionnaire. Result: The result showed that product (type of services, infrastructure and facility, relative price, comfortable and safe place, targeted promotion, trained human resources, standard process and provision of customer service are an important aspect to implement strategy marketing to increase Bed Occupancy Rate. Analysis: The result of this study has enlightened the importance of strategy marketing in health care services based on seven principle of marketing mix. Discussion: Implementation of marketing mix in obstetric gynecology ward 2 need to be considered.

  20. Migrant adults with diabetes in France: Influence of family migration

    Directory of Open Access Journals (Sweden)

    C. Chambre

    2017-03-01

    Conclusions: We may fear that migrants share an increased risk of uncontrolled diabetes. Individual migration could be a risk factor of uncontrolled diabetes. Knowing the migration history of migrant patients is fundamental to understand some barriers of care.

  1. Stent migration following endoscopic suture fixation of esophageal self-expandable metal stents: a systematic review and meta-analysis.

    Science.gov (United States)

    Law, Ryan; Prabhu, Anoop; Fujii-Lau, Larissa; Shannon, Carol; Singh, Siddharth

    2018-02-01

    Covered self-expandable metal stents (SEMS) are utilized for the management of benign and malignant esophageal conditions; however, covered SEMS are prone to migration. Endoscopic suture fixation may mitigate the migration risk of covered esophageal SEMS. Hence, we conducted a systematic review and meta-analysis to evaluate the effectiveness and safety of endoscopic suture fixation for covered esophageal SEMS. Following PRISMA guidelines, we performed a systematic review from 2011 to 2016 to identify studies (case control/case series) reporting the technical success and migration rate of covered esophageal SEMS following endoscopic suture fixation. We searched multiple electronic databases and conference proceedings. We calculated pooled rates (and 95% confidence intervals [CI]) of technical success and stent migration using a random effects model. We identified 14 studies (212 patients) describing covered esophageal SEMS placement with endoscopic suture fixation. When reported, SEMS indications included leak/fistula (n = 75), stricture (n = 65), perforation (n = 10), and achalasia (n = 4). The pooled technical success rate was 96.7% (95% CI 92.3-98.6), without heterogeneity (I 2  = 0%). We identified 29 SEMS migrations at rate of 15.9% (95% CI 11.4-21.6), without heterogeneity (I 2  = 0%). Publication bias was observed, and using the trim-and-fill method, a more conservative estimate for stent migration was 17.0%. Suture-related adverse events were estimated to occur in 3.7% (95% CI 1.6-8.2) of cases. Endoscopic suture fixation of covered esophageal SEMS appears to reduce stent migration when compared to published rates of non-anchored SEMS. However, SEMS migration still occurs in approximately 1 out of 6 cases despite excellent immediate technical success and low risk of suture-related adverse events.

  2. Regularized plane-wave least-squares Kirchhoff migration

    KAUST Repository

    Wang, Xin

    2013-09-22

    A Kirchhoff least-squares migration (LSM) is developed in the prestack plane-wave domain to increase the quality of migration images. A regularization term is included that accounts for mispositioning of reflectors due to errors in the velocity model. Both synthetic and field results show that: 1) LSM with a reflectivity model common for all the plane-wave gathers provides the best image when the migration velocity model is accurate, but it is more sensitive to the velocity errors, 2) the regularized plane-wave LSM is more robust in the presence of velocity errors, and 3) LSM achieves both computational and IO saving by plane-wave encoding compared to shot-domain LSM for the models tested.

  3. Human endogenous retrovirus W env increases nitric oxide production and enhances the migration ability of microglia by regulating the expression of inducible nitric oxide synthase.

    Science.gov (United States)

    Xiao, Ran; Li, Shan; Cao, Qian; Wang, Xiuling; Yan, Qiujin; Tu, Xiaoning; Zhu, Ying; Zhu, Fan

    2017-06-01

    Human endogenous retrovirus W env (HERV-W env) plays a critical role in many neuropsychological diseases such as schizophrenia and multiple sclerosis (MS). These diseases are accompanied by immunological reactions in the central nervous system (CNS). Microglia are important immunocytes in brain inflammation that can produce a gasotransmitter-nitric oxide (NO). NO not only plays a role in the function of neuronal cells but also participates in the pathogenesis of various neuropsychological diseases. In this study, we reported increased NO production in CHME-5 microglia cells after they were transfected with HERV-W env. Moreover, HERV-W env increased the expression and function of human inducible nitric oxide synthase (hiNOS) and enhanced the promoter activity of hiNOS. Microglial migration was also enhanced. These data revealed that HERV-W env might contribute to increase NO production and microglial migration ability in neuropsychological disorders by regulating the expression of inducible NOS. Results from this study might lead to the identification of novel targets for the treatment of neuropsychological diseases, including neuroinflammatory diseases, stroke, and neurodegenerative diseases.

  4. Brine migration resulting from pressure increases in a layered subsurface system

    Science.gov (United States)

    Delfs, Jens-Olaf; Nordbeck, Johannes; Bauer, Sebastian

    2016-04-01

    Brine originating from the deep subsurface impairs parts of the freshwater resources in the North German Basin. Some of the deep porous formations (esp. Trias and Jurassic) exhibit considerable storage capacities for waste fluids (CO2, brine from oil production or cavern leaching), raising concerns among water providers that this type of deep subsurface utilization might impair drinking water supplies. On the one hand, overpressures induced by fluid injections and the geothermal gradient support brine migration from deep into shallow formations. On the other hand, the rising brine is denser than the surrounding less-saline formation waters and, therefore, tends to settle down. Aim of this work is to investigate the conditions under which pressurized formation brine from deep formations can reach shallow freshwater resources. Especially, the role of intermediate porous formations between the storage formation and the groundwater is studied. For this, complex thermohaline simulations using a coupled numerical process model are necessary and performed in this study, in which fluid density depends on fluid pressure, temperature and salt content and the governing partial differential equations are coupled. The model setup is 2D and contains a hypothetic series of aquifers and barriers, each with a thickness of 200 m. Formation pressure is increased at depths of about 2000 m in proximity to a salt wall and a permeable fault. The domain size reaches up to tens of kilometers horizontally to the salt wall. The fault connects the injection formation and the freshwater aquifer such that conditions can be considered as extremely favorable for induced brine migration (worst case scenarios). Brine, heat, and salt fluxes are quantified with reference to hydraulic permeabilities, storage capacities (in terms of domain size), initial salt and heat distribution, and operation pressures. The simulations reveal the development of a stagnation point in the fault region in each

  5. The role of natural organic matter in the migration behaviour of americium in the Boom clay - Part II: analysis of migration experiments

    International Nuclear Information System (INIS)

    Hicks, T.; Bennett, D.; Maes, N.; Wang, L.; Warwick, P.; Hall, T.; Walker, G.; Dierckx, A.

    2005-01-01

    Full text of publication follows: In demonstrating the suitability of Boom Clay as a potential site for the disposal of radioactive waste in Belgium, the role of the relatively high amount of Natural Organic Matter (NOM) present in the Boom Clay on the mobility of critical radionuclides needs investigation. Trivalent actinides and lanthanides form strong complexes with humic substances. Complexation of these trivalent radionuclides with NOM present in the Boom Clay may have opposing effects. If complexed by the aqueous phase (mobile) NOM, radionuclide transport will be governed by the mobility of these dissolved radionuclide-NOM species. If complexed by the solid phase (immobile) NOM, migration will be retarded. One of the aims of the EC projects TRANCOM-Clay and TRANCOM-II was to investigate the role of mobile NOM as radionuclide carrier with the objective of deriving conceptual models that can be implemented in repository performance assessment (PA) models. A separate paper describes the results of column migration experiments involving the transport of 241 Am- 14 C-NOM complexes through Boom Clay cores. This paper describes the transport model, POPCORN, that was developed to describe and evaluate the influence of NOM on radionuclide transport in clay, taking into account attachment/detachment rates of NOM to clay surfaces and the kinetics of RN complexation to, and destabilization from, NOM. The POPCORN model was used to evaluate diffusion experiments involving injection of 14 C-labelled NOM in Boom Clay cores. Model fits were obtained by varying the rates of filtration of NOM by attachment to the surface of the clay matrix. POPCORN was then used to analyse the 241 Am- 14 C-NOM migration experiments. The stability properties of the 241 Am-NOM were characterised by kinetic constants, and good matches to the migration data were achieved for the experiments. The findings suggest that a small sub-population of the original 241 Am-OM is the most stable, and that this

  6. Brine migration in salt and its implications in the geologic disposal of nuclear waste

    International Nuclear Information System (INIS)

    Jenks, G.H.; Claiborne, H.C.

    1981-12-01

    This report respresents a comprehensive review and analysis of available information relating to brine migration in salt surrounding radioactive waste in a salt repository. The topics covered relate to (1) the characteristics of salt formations and waste packages pertinent to considerations of rates, amounts, and effects of brine migration, (2) experimental and theoretical information on brine migration, and (3) means of designing to minimize any adverse effects of brine migration. Flooding, brine pockets, and other topics were not considered, since these features will presumably be eliminated by appropriate site selection and repository design. 115 references

  7. Stellar Angular Momentum Distributions and Preferential Radial Migration

    Science.gov (United States)

    Wyse, Rosemary; Daniel, Kathryne J.

    2018-04-01

    I will present some results from our recent investigations into the efficiency of radial migration in stellar disks of differing angular momentum distributions, within a given adopted 2D spiral disk potential. We apply to our models an analytic criterion that determines whether or not individual stars are in orbits that could lead to radial migration around the corotation resonance. We couch our results in terms of the local stellar velocity dispersion and find that the fraction of stars that could migrate radially decreases as the velocity dispersion increases. I will discuss implications and comparisons with the results of other approaches.

  8. Hsc70 regulates cell surface ASIC2 expression and vascular smooth muscle cell migration.

    Science.gov (United States)

    Grifoni, Samira C; McKey, Susan E; Drummond, Heather A

    2008-05-01

    Recent studies suggest members of the degenerin (DEG)/epithelial Na(+) channel (ENaC)/acid-sensing ion channel (ASIC) protein family play an important role in vascular smooth muscle cell (VSMC) migration. In a previous investigation, we found suppression of a certain DEG/ENaC/ASIC member, ASIC2, increased VSMC chemotactic migration, raising the possibility that ASIC2 may play an inhibitory role. Because ASIC2 protein was retained in the cytoplasm, we reasoned increasing surface expression of ASIC2 might unmask the inhibitory role of ASIC2 in VSMC migration so we could test the hypothesis that ASIC2 inhibits VSMC migration. Therefore, we used the chemical chaperone glycerol to enhance ASIC2 expression. Glycerol 1) increased cytoplasm ASIC2 expression, 2) permitted detection of ASIC2 at the cell surface, and 3) inhibited platelet-derived growth factor (PDGF)-bb mediated VSMC migration. Furthermore, ASIC2 silencing completely abolished the inhibitory effect of glycerol on migration, suggesting upregulation of ASIC2 is responsible for glycerol-induced inhibition of VSMC migration. Because other investigators have shown that glycerol regulates ENaC/ASIC via interactions with a certain heat shock protein, heat shock protein 70 (Hsc70), we wanted to determine the importance of Hsc70 on ASIC2 expression in VSMCs. We found that Hsc70 silencing increases ASIC2 cell surface expression and inhibits VSMC migration, which is abolished by cosilencing ASIC2. These data demonstrate that Hsc70 inhibits ASIC2 expression, and, when the inhibitory effect of Hsc70 is removed, ASIC2 expression increases, resulting in reduced VSMC migration. Because VSMC migration contributes to vasculogenesis and remodeling following vascular injury, our findings raise the possibility that ASIC2-Hsc70 interactions may play a role in these processes.

  9. Short-run Distributional Effects of VAT Rate Change: Evidence from a consumption tax rate increase in Japan

    OpenAIRE

    David CASHIN; UNAYAMA Takashi

    2012-01-01

    Households will purchase more items than usual prior to a value added tax (VAT) rate increase in order to avoid taxation. Since this type of arbitrage requires resources such as shopping time and storage space, the impacts of tax increases vary across households, which has brought distributional effects in the short-run. Using the case of a consumption tax rate increase in Japan in 1997, we show that households who are non-working, with non-working spouses and residing in larger houses, benef...

  10. 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.

  11. Migration, settlement change and health in post-apartheid South Africa: triangulating health and demographic surveillance with national census data.

    Science.gov (United States)

    Collinson, Mark A; Tollman, Stephen M; Kahn, Kathleen

    2007-08-01

    World population growth will be increasingly concentrated in the urban areas of the developing world; however, some scholars caution against the oversimplification of African urbanization noting that there may be "counter-urbanization" and a prevailing pattern of circular rural-urban migration. The aim of the paper is to examine the ongoing urban transition in South Africa in the post-apartheid period, and to consider the health and social policy implications of prevailing migration patterns. Two data sets were analysed, namely the South African national census of 2001 and the Agincourt health and demographic surveillance system. A settlement-type transition matrix was constructed on the national data to show how patterns of settlement have changed in a five-year period. Using the sub-district data, permanent and temporary migration was characterized, providing migration rates by age and sex, and showing the distribution of origins and destinations. The comparison of national and sub-district data highlight the following features: urban population growth, particularly in metropolitan areas, resulting from permanent and temporary migration; prevailing patterns of temporary, circular migration, and a changing gender balance in this form of migration; stepwise urbanization; and return migration from urban to rural areas. Policy concerns include: rural poverty exacerbated by labour migration; explosive conditions for the transmission of HIV; labour migrants returning to die in rural areas; and the challenges for health information created by chronically ill migrants returning to rural areas to convalesce. Lastly, suggestions are made on how to address the dearth of relevant population information for policy-making in the fields of migration, settlement change and health.

  12. Normal and abnormal neuronal migration in the developing cerebral cortex.

    Science.gov (United States)

    Sun, Xue-Zhi; Takahashi, Sentaro; Cui, Chun; Zhang, Rui; Sakata-Haga, Hiromi; Sawada, Kazuhiko; Fukui, Yoshihiro

    2002-08-01

    Neuronal migration is the critical cellular process which initiates histogenesis of cerebral cortex. Migration involves a series of complex cell interactions and transformation. After completing their final mitosis, neurons migrate from the ventricular zone into the cortical plate, and then establish neuronal lamina and settle onto the outermost layer, forming an "inside-out" gradient of maturation. This process is guided by radial glial fibers, requires proper receptors, ligands, other unknown extracellular factors, and local signaling to stop neuronal migration. This process is also highly sensitive to various physical, chemical and biological agents as well as to genetic mutations. Any disturbance of the normal process may result in neuronal migration disorder. Such neuronal migration disorder is believed as major cause of both gross brain malformation and more special cerebral structural and functional abnormalities in experimental animals and in humans. An increasing number of instructive studies on experimental models and several genetic model systems of neuronal migration disorder have established the foundation of cortex formation and provided deeper insights into the genetic and molecular mechanisms underlying normal and abnormal neuronal migration.

  13. 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.

  14. On the development of a bedform migration model

    DEFF Research Database (Denmark)

    Bartholdy, Jesper; Ernstsen, V.B.; Flemming, B.W.

    2008-01-01

    A model linking subaqueous dune migration to the effective (grain related) shear stress is calibrated by means of flume data for bedform dimensions and migration rates. The effective shear stress is calculated on the basis of a new method assuming a near-bed layer above the mean bed level in which...... the current velocity accelerates towards the bedform crest. As a consequence, the effective bed shear stress corresponds to the shear stress acting directly on top of the bedform. The model operates with the critical Shields stress as a function of grain size. It predicts the deposition (volume per unit time...

  15. ORBITAL MIGRATION OF LOW-MASS PLANETS IN EVOLUTIONARY RADIATIVE MODELS: AVOIDING CATASTROPHIC INFALL

    International Nuclear Information System (INIS)

    Lyra, Wladimir; Mac Low, Mordecai-Mark; Paardekooper, Sijme-Jan

    2010-01-01

    Outward migration of low-mass planets has recently been shown to be a possibility in non-barotropic disks. We examine the consequences of this result in evolutionary models of protoplanetary disks. Planet migration occurs toward equilibrium radii with zero torque. These radii themselves migrate inwards because of viscous accretion and photoevaporation. We show that as the surface density and temperature fall the planet orbital migration and disk depletion timescales eventually become comparable, with the precise timing depending on the mass of the planet. When this occurs, the planet decouples from the equilibrium radius. At this time, however, the gas surface density is already too low to drive substantial further migration. A higher mass planet, of 10 M + , can open a gap during the late evolution of the disk, and stops migrating. Low-mass planets, with 1 or 0.1 M + , released beyond 1 AU in our models avoid migrating into the star. Our results provide support for the reduced migration rates adopted in recent planet population synthesis models.

  16. Migration and Singapore: implications for the Asia Pacific.

    Science.gov (United States)

    Low, L

    1994-01-01

    Regarding immigration and emigration issues, there is a need for greater and more detailed data collection, an emphasis on data on illegal as well as legal migration, an examination of the impact of direct foreign investment on job creation and new labor market entrants, and a strengthening of international conventions for protection of foreign workers. The Pacific Economic Cooperation Council (PECC), Human Resource Development Task Force, is the source for projections of labor demand and supply for 18 PECC countries in 1993 and 1994. These projections indicate labor shortages in 1993 in Canada, Taiwan, Hong Kong, Malaysia, Singapore, and Thailand. The greatest labor supplier will be China. Japan and Korea are expected to have economic downturns, which will increase excess labor. The extent of excess labor is estimated to be 8.01 million in 1993 and 12.43 in 1994. The nature of the calculations could potentially exaggerate existing demand. A variety of theories are used to determine the direction and flow of migration, capital, goods and services, and technology. Estimates of migration flows indicate an increase to 100 million migrants in 1992, or 1.8% of world population (35 million in Sub-Saharan Africa, 15 million in Asia and the Middle East, and almost 13 million in Western Europe and North America). The value of remittances is estimated at $66 million (US dollars), which is slightly less than the value of oil trade and exceeds the $46 million in foreign aid. It is hypothesized that wider spatial and income inequalities with expanding globalization will increase migration flows. The case of Singapore illustrates how manipulation of the labor market reduces potential problems. Immigration policy historically encouraged migration of skilled and professional workers. In 1990 foreign workers in Singapore constituted 12% of the labor force. Since 1982 a monthly foreign worker levy has been imposed. The levy is increased when needed in order to slow demand. In 1992

  17. Migration of fresh and cryopreserved human spermatozoa in polyacrylamide gel.

    Science.gov (United States)

    Goldstein, M C; Wix, L S; Foote, R H; Feldschuh, R; Feldschuh, J

    1982-05-01

    The ability of freshly collected and frozen human spermatozoa to migrate in round capillary tubes containing specially formulated polyacrylamide gel was investigated, using 33 ejaculates from 27 donors. Each semen sample was divided; one portion was left undiluted, and the other portion was diluted to 50 x 10(6) sperm/ml. Glycerol was used as the cryoprotectant. The percentage of motile sperm cells was determined before and after freezing. Fresh semen contained a higher percentage of motile cells, which migrated farther than those of cryopreserved-thawed semen. Various correlations between the percentage of motile sperm and migration distance ranged from 0.57 to 0.62. There was a low positive correlation of migration distance with sperm cell concentration per milliliter, r = 0.25 to 0.34; and thus adjusting semen samples to a standard sperm concentration improved the accuracy of the test only slightly. The regression coefficient of migration distance on the percentage of motile sperm in fresh semen was 0.65, indicating that for each 10% increase in sperm motility, migration distance is predicted to increase 6.5 mm. Five batches of polyacrylamide gel gave uniform results, and the application of this stable gel to fertility investigations is discussed.

  18. Mir-513a-3p contributes to the controlling of cellular migration processes in the A549 lung tumor cells by modulating integrin β-8 expression.

    Science.gov (United States)

    da Silveira, Marina Bonfogo; Lima, Kelvin Furtado; da Silva, Andrea Renata; Dos Santos, Robson Augusto Souza; Moraes, Karen C M

    2017-12-04

    Lung tumors are a frequent type of cancer in humans and a leading cause of death, and the late diagnostic contributes to high mortality rates. New therapeutic strategies are needed, and the heptapeptide angiotensin-(1-7) [ang-(1-7)] demonstrated the ability to control cancer growth rates and migration in vitro and in vivo. However, the possible use of the heptapeptide in clinical trials demands deeper analyses to elucidate molecular mechanisms of its effect in the target cells. In this study, we investigated relevant elements that control pro-inflammatory environment and cellular migration, focusing in the post-transcription mechanism using lung tumor cell line. In our cellular model, the microRNA-513a-3p was identified as a novel element targeting ITG-β8, thereby controlling the protein level and its molecular function in the controlling of migration and pro-inflammatory environment. These findings provide useful information for future studies, using miR-513a-3p as an innovative molecular tool to control lung tumor cell migration, which will support more effective clinical treatment of the patients with the widely used chemotherapeutic agents, increasing survival rates.

  19. Phase-field simulation study of the migration of recrystallization boundaries

    DEFF Research Database (Denmark)

    Moelans, Nele; Godfrey, Andy; Zhang, Yubin

    2013-01-01

    We present simulation results based on a phase-field model that describes the local migration of recrystallization boundaries into varying deformation energy fields. An important finding from the simulations is that the overall migration rate of the recrystallization front can be considerably...... amplitudes, however, the velocity scales with the maximum of the deformation energy density along the variation, resulting in a considerably larger velocity than that obtained from standard recrystallization models. The shape of the migrating grain boundary greatly depends on the local characteristics...... of the varying stored deformation energy field. For different deformation energy fields, the simulation results are in good qualitative agreement with experiments and add information which cannot be directly derived from experiments....

  20. A generic model of contaminant migration from uranium tailings impoundments

    International Nuclear Information System (INIS)

    Shepherd, T.A.; Brown, S.E.

    1982-01-01

    This paper presents an analytical hydrogeochemical model based upon acid consumption-neutralization front movement. The development of contaminant plumes is discussed and distinct zones within these plumes are identified and characterized. The most important process influencing the rate and extent of contaminant migration at acid-leach uranium tailings impoundments is the neutralization of seepage water by soils along ground water flow paths. The chemical characteristics of the ground water is determined in order to identify and characterize zones within migrating plumes of tailings-derived water. It is concluded that the characterization of specific zones is useful in the interpretation of existing conditions, in the evaluation of future migration, and in the determination of appropriate models for the specific situation