WorldWideScience

Sample records for interkinetic nuclear migration

  1. Interkinetic nuclear migration in the mouse embryonic ureteric epithelium: Possible implication for congenital anomalies of the kidney and urinary tract.

    Science.gov (United States)

    Motoya, Tomoyuki; Ogawa, Noriko; Nitta, Tetsuya; Rafiq, Ashiq Mahmood; Jahan, Esrat; Furuya, Motohide; Matsumoto, Akihiro; Udagawa, Jun; Otani, Hiroki

    2016-05-01

    Interkinetic nuclear migration (INM) is a phenomenon in which progenitor cell nuclei migrate along the apico-basal axis of the pseudostratified epithelium, which is characterized by the presence of apical primary cilia, in synchrony with the cell cycle in a manner of apical mitosis. INM is suggested to regulate not only stem/progenitor cell proliferation/differentiation but also organ size and shape. INM has been reported in epithelia of both ectoderm and endoderm origin. We examined whether INM exists in the mesoderm-derived ureteric epithelium. At embryonic day (E) 11.5, E12.5 and E13.5, C57BL/6J mouse dams were injected with 5-bromo-2'-deoxyuridine (BrdU) and embryos were killed 1, 2, 4, 6, 8, 10 and 12 h later. We immunostained transverse sections of the ureter for BrdU, and measured the position of BrdU (+) nuclei in the ureteric epithelia along the apico-basal axis at each time point. We analyzed the distribution patterns of BrdU (+) nuclei in histograms using the multidimensional scaling. Changes in the nucleus distribution patterns suggested nucleus movement characteristic of INM in the ureteric epithelia, and the mode of INM varied throughout the ureter development. While apical primary cilia are related with INM by providing a centrosome for the apical mitosis, congenital anomalies of the kidney and urinary tract (CAKUT) include syndromes linked to primary ciliary dysfunction affecting epithelial tubular organs such as kidney, ureter, and brain. The present study showed that INM exists in the ureteric epithelium and suggests that INM may be related with the CAKUT etiology via primary ciliary protein function. © 2015 Japanese Teratology Society.

  2. Mesoscale Simulations of Pore Migration in a Nuclear Fuel

    International Nuclear Information System (INIS)

    Radhakrishnan, Balasubramaniam; Gorti, Sarma B.

    2010-01-01

    The evolution of pore and grain structure in a nuclear fuel environment is strongly influenced by the local temperature, and the temperature gradient. The evolution of pore and grain structure in an externally imposed temperature gradient is simulated for a hypothetical material using a Potts model approach that allows for porosity migration by mechanisms similar to surface, grain boundary and volume diffusion, as well as the interaction of migrating pores with stationary grain boundaries. First, the migration of a single pore in a single crystal in the presence of the temperature gradient is simulated. Next, the interaction of a pore moving in a temperature gradient with a grain boundary that is perpendicular to the pore migration direction is simulated in order to capture the force exerted by the pore on the grain boundary. The simulations reproduce the expected variation of pore velocity with pore size as well as the variation of the grain boundary force with pore size.

  3. Tritium migration in nuclear desalination plants

    International Nuclear Information System (INIS)

    Muralev, E.D.

    2003-01-01

    Tritium transport, as one of important items of radiation safety assessment, should be taken into consideration before construction of a Nuclear Desalination Plant (NDP). The influence of tritium internal exposition to the human body is very dangerous because of 3 H associations with water molecules. The problem of tritium in nuclear engineering is connected to its high penetration ability (through fuel element cans and other construction materials of a reactor), with the difficulty of extracting tritium from process liquids and gases. Sources of tritium generation in NDP are: nuclear fuel, boron in control rods, and deuterium in heat carrier. Tritium passes easily through the walls of a reactor vessel, intermediate heat exchangers, steam generators and other technological equipment, through the walls of heat carrier pipelines. The release of tritium and its transport could be assessed, using mathematical models, based on the assumption that steady state equilibrium has been attained between the sources of tritium, produced water and release to the environment. Analysis of the model shows the tritium concentration dependence in potable water on design features of NDP. The calculations obtained and analysis results for NDP with BN-350 reactor give good convergence. According to the available data, tritium concentration in potable water is less than the statutory maximum concentration limit. The design of a NDP requires elaboration of technical solutions, capable of minimising the release of tritium to potable water produced. (author)

  4. Repository-analog experiments of nuclear waste leaching and migration

    International Nuclear Information System (INIS)

    Seitz, M.G.

    1982-01-01

    The potential for radionuclide migration from a breached nuclear-waste repository depends on the leaching and subsequent interaction of the leached radionuclides with materials in the groundwater flow path. An attempt is made to consider all interactions using experiments that integrate repository materials. Results of a repository-analog experiment using borosilicate glass, fissured granite, and flowing water suggest: (1) plutonium was immobile possibly because of its low solubility; (2) caesium migrated down slowly because of sorption; and (3) neptunium remained oxidized even in water of low oxidation potential. By summing the effects of all interactions, not just sorption, the repository-analog experiment produced radionuclide migration that could be expected from a breached repository. (author)

  5. Analytical study in 1D nuclear waste migration

    International Nuclear Information System (INIS)

    Perez Guerrero, Jesus S.; Heilbron Filho, Paulo L.; Romani, Zrinka V.

    1999-01-01

    The simulation of the nuclear waste migration phenomena are governed mainly by diffusive-convective equation that includes the effects of hydrodynamic dispersion (mechanical dispersion and molecular diffusion), radioactive decay and chemical interaction. For some special problems (depending on the boundary conditions and when the domain is considered infinite or semi-infinite) an analytical solution may be obtained using classical analytical methods such as Laplace Transform or variable separation. The hybrid Generalized Integral Transform Technique (GITT) is a powerful tool that can be applied to solve diffusive-convective linear problems to obtain formal analytical solutions. The aim of this work is to illustrate that the GITT may be used to obtain an analytical formal solution for the study of migration of radioactive waste in saturated flow porous media. A case test considering 241 Am radionuclide is presented. (author)

  6. Migration of tritium from a nuclear waste burial site

    International Nuclear Information System (INIS)

    Hawkins, R.H.

    1975-09-01

    The Savannah River Plant (SRP) has routinely and continuously monitored the local environment (land, water, air, flora, and fauna) since 1951. As part of this intensive program, a three-part study was made to assess the tritium migration from an onsite burial ground for solid nuclear wastes and the resulting dose-to-man. A major source of tritium is buried, massive, Li-Al residues (referred to as melts) from the thermal extraction step in the SRP tritium production process. A melt with its extraction crucible and lid were immersed in water to measure the amounts of tritium released as HTO and HT to the water and to air. The result was a rapid release of 23 curies, of which approximately 99 percent was HTO that remained in the immersion water, and 1 percent was HT that passed into the air. (auth)

  7. Spatial pattern analysis of nuclear migration in remodelled muscles during Drosophila metamorphosis.

    Science.gov (United States)

    Kuleesha; Feng, Lin; Wasser, Martin

    2017-07-10

    Many human muscle wasting diseases are associated with abnormal nuclear localization. During metamorphosis in Drosophila melanogaster, multi-nucleated larval dorsal abdominal muscles either undergo cell death or are remodeled to temporary adult muscles. Muscle remodeling is associated with anti-polar nuclear migration and atrophy during early pupation followed by polar migration and muscle growth during late pupation. Muscle remodeling is a useful model to study genes involved in myonuclear migration. Previously, we showed that loss of Cathepsin-L inhibited anti-polar movements, while knockdown of autophagy-related genes affected nuclear positioning along the medial axis in late metamorphosis. To compare the phenotypic effects of gene perturbations on nuclear migration more objectively, we developed new descriptors of myonuclear distribution. To obtain nuclear pattern features, we designed an algorithm to detect and track nuclear regions inside live muscles. Nuclear tracks were used to distinguish between fast moving nuclei associated with fragments of dead muscles (sarcolytes) and slow-moving nuclei inside remodelled muscles. Nuclear spatial pattern features, such as longitudinal (lonNS) and lateral nuclear spread (latNS), allowed us to compare nuclear migration during muscle remodelling in different genetic backgrounds. Anti-polar migration leads to a lonNS decrease. As expected, lack of myonuclear migration caused by the loss of Cp1 was correlated with a significantly lower lonNS decrease. Unexpectedly, the decrease in lonNS was significantly enhanced by Atg9, Atg5 and Atg18 silencing, indicating that the loss of autophagy promotes the migration and clustering of nuclei. Loss of autophagy also caused a scattering of nuclei along the lateral axis, leading to a two-row as opposed to single row distribution in control muscles. Increased latNS resulting from knockdown of Atg9 and Atg18 was correlated with increased muscle diameter, suggesting that the wider muscle

  8. Emerging role for nuclear rotation and orientation in cell migration

    Czech Academy of Sciences Publication Activity Database

    Maninová, Miloslava; Iwanicki, M. P.; Vomastek, Tomáš

    2014-01-01

    Roč. 8, č. 1 (2014), s. 42-48 ISSN 1933-6918 R&D Projects: GA ČR GA204/09/0614 Grant - others:Marie Cúrie EU FP7(BE) 231086 Institutional support: RVO:61388971 Keywords : cell polarity * actin * migration * microtubules Subject RIV: EE - Microbiology, Virology Impact factor: 4.505, year: 2014

  9. Cdk1 Activates Pre-Mitotic Nuclear Envelope Dynein Recruitment and Apical Nuclear Migration in Neural Stem cells

    Science.gov (United States)

    Baffet, Alexandre D.; Hu, Daniel J.; Vallee, Richard B.

    2015-01-01

    Summary Dynein recruitment to the nuclear envelope is required for pre-mitotic nucleus-centrosome interactions in nonneuronal cells, and for apical nuclear migration in neural stem cells. In each case, dynein is recruited to the nuclear envelope (NE) specifically during G2, via two nuclear pore-mediated mechanisms involving RanBP2-BicD2 and Nup133-CENP-F. The mechanisms responsible for cell cycle control of this behavior are unknown. We now find that Cdk1 serves as a direct master controller for NE dynein recruitment in neural stem cells and HeLa cells. Cdk1 phosphorylates conserved sites within RanBP2 and activates BicD2 binding and early dynein recruitment. Late recruitment is triggered by a Cdk1-induced export of CENP-F from the nucleus. Forced NE targeting of BicD2 overrides Cdk1 inhibition, fully rescuing dynein recruitment and nuclear migration in neural stem cells. These results reveal how NE dynein recruitment is cell cycle regulated, and identify the trigger mechanism for apical nuclear migration in the brain. PMID:26051540

  10. Tritium and chlorine-36 migration from a nuclear explosion cavity

    International Nuclear Information System (INIS)

    Burbey, T.J.; Wheatcraft, S.W.

    1986-04-01

    The Radionuclide Migration (RNM) Experiment consists of a 600 gpm pumping well placed approximately 90 m away from the center of the rubble chimney and cavity created by the 1965 Cambric event. The purpose of the experiment is to deliberately draw radionuclides away from the cavity and produce breakthrough curves of the migrating radionuclides at the pumping well. Tritium and chlorine-36 are the most mobile radionuclides and they have produced breakthrough curves that are very amenable to analysis. The other radionuclides that have been observed at the pumping well are ruthenium-106, Kr-85 and I-129, in very small quantities. A conceptual model of the Cambric cavity and surrounding hydrogeologic environment was formulated using available field data such as core samples and the breakthrough curves of tritium and chlorine-36. Results show that the cavity hydraulic conductivity is about one-tenth as large as the average hydraulic conductivity of the surrounding medium. The calibrated model required the addition of retardation of the tritium. The breakthrough curve was relatively insensitive to variations in the other parameters tested in the sensitivity study

  11. EXFOR-CINDA-ENDF: Migration of Databases to Give Higher-Quality Nuclear Data Services

    International Nuclear Information System (INIS)

    Zerkin, V.V.; McLane, V.; Herman, M.W.; Dunford, C.L.

    2005-01-01

    Extensive work began in 1999 to migrate the EXFOR, CINDA, and ENDF nuclear reaction databases, and convert the available nuclear data services from VMS to a modern computing environment. This work has been performed through co-operative efforts between the IAEA Nuclear Data Section (IAEA-NDS) and the National Nuclear Data Center (NNDC), Brookhaven National Laboratory. The project also afforded the opportunity to make general revisions and improvements to the nuclear reaction data services by taking account of past experience with the old system and users' feedback. A main goal of the project was to implement databases in a relational form that provides full functionality for maintenance by data centre staff and improved retrieval capability for external users. As a result, the quality of our nuclear service has significantly improved, with better functionality of the system, accessibility of data, and improved data retrieval functions for users involved in a wide range of applications

  12. MODELLING OF RADIONUCLIDE MIGRATION IN THE SYSTEM OF NUCLEAR POWER PLANT BIOLOGICAL PONDS

    Directory of Open Access Journals (Sweden)

    Ю. Кутлахмедов

    2011-04-01

    Full Text Available Migration of radionuclide coming from nuclear power plant into the system of biological pondsand then into the water reservoir-cooler is considered in the article. The theme of the work ismodeling of radionuclide migration process in the system of biological ponds on the example of thePivdennoukrainska nuclear power plant using chamber models method. Typical water ecosystemconsisting of three chambers (chamber-water, chamber-biota and chamber-bed silt was the basistaken by the authors. Application of chamber models method allowed authors to develop thedynamic chamber model of radionuclide migration in nuclear power plant biological ponds. Thismodel allows to forecast values and dynamics of radioactive water pollution based on limitedecosystem monitoring data. Thus, parameters of radioactive capacity of nuclear power plantbiological ponds system and water reservoir-cooler were modeled by authors, the estimation andprognosis of radionuclide distribution and accumulation in the system of nuclear power plantbiological ponds were done. Authors also explain the roles of basin water, biomass and bed silt inradionuclide deposition

  13. Migration of radionuclides through backfill in a nuclear waste repository

    International Nuclear Information System (INIS)

    Lung, H.

    1986-01-01

    Four models are analyzed to predict the performance of a backfill layer as part of the waste package emplacement in a nuclear waste repository. The corresponding computer code for each model is also developed. The time-dependent mass transfer analysis on a spherical waste-backfill geometry indicates that the radioactive decay effect can enhance the mass transfer rate from the backfill instead of reducing it. The analysis yields the breakthrough time of the backfill layer, which in turn characterizes the backfill performance. A non-linear (Langmuir) sorption isotherm is used to describe the sorption saturation in the backfill. The steady state mass transport analysis through a prolate spheroidal waste-backfill geometry shows that a simple formula can be used to calculate the individual resistances to mass transport in backfill and in host rock. A general, non-recursive analytical solution is derived for a radioactive decay chain of arbitrary length in either a finite or a semi-infinite medium. Numerical examples are given for different boundary conditions and for different decay chains. The results justify that for a backfill layer made of low permeability material, a zero water velocity can be used in the backfill analysis. It is also shown that under normal repository conditions, the mass transfer rate from the backfill is quite small. For the daughter member with a smaller retardation coefficient than that of the mother nuclide, such as 226 Ra in the 234 U → 230 Th → 226 Ra chain, an interior maximum in the concentration profile appears in the backfill. This phenomenon can be seen only in a chain calculation

  14. Migration of nuclear criticality safety software from a mainframe to a workstation environment

    International Nuclear Information System (INIS)

    Bowie, L.J.; Robinson, R.C.; Cain, V.R.

    1993-01-01

    The Nuclear Criticality Safety Department (NCSD), Oak Ridge Y-12 Plant has undergone the transition of executing the Martin Marietta Energy Systems Nuclear Criticality Safety Software (NCSS) on IBM mainframes to a Hewlett-Packard (HP) 9000/730 workstation (NCSSHP). NCSSHP contains the following configuration controlled modules and cross-section libraries: BONAMI, CSAS, GEOMCHY, ICE, KENO IV, KENO Va, MODIIFY, NITAWL SCALE, SLTBLIB, XSDRN, UNIXLIB, albedos library, weights library, 16-Group HANSEN-ROACH master library, 27-Group ENDF/B-IV master library, and standard composition library. This paper will discuss the method used to choose the workstation, the hardware setup of the chosen workstation, an overview of Y-12 software quality assurance and configuration control methodology, code validation, difficulties encountered in migrating the codes, and advantages to migrating to a workstation environment

  15. Accommodating ground water velocity uncertainties in the advection-dispersion approach to geologic nuclear waste migration

    International Nuclear Information System (INIS)

    Thomas, G.F.

    1994-01-01

    This note shows how uncertainties in nearfield and farfield ground water velocities affect the inventory that migrates from a geologic nuclear waste repository within the classical advection-dispersion approach and manifest themselves through both the finite variances and covariances in the activities of transported nuclides and in the apparent scale dependence of the host rock's dispersivity. Included is a demonstration of these effects for an actinide chain released from used CANDU fuel buried in a hypothetical repository. (Author)

  16. Modelling and prediction of radionuclide migration from shallow, subgrade nuclear waste facilities in arid environments

    International Nuclear Information System (INIS)

    Smith, A.; Ward, A.; Geldenhuis, S.

    1986-01-01

    Over the past fifteen years, prodigious efforts and significant advances have been made in methods of prediction of the migration rate of dissolved species in aqueous systems. Despite such work, there remain formidable obstacles in prediction of solute transport in the unsaturated zone over the long time periods necessarily related to the radionuclide bearing wastes. The objective of this paper is to consider the methods, issues and problems with the use of predictive solute transport models for radionuclide migration from nuclear waste disposal in arid environments, if and when engineering containment of the waste fails. Having considered the ability for long term solute prediction for a number of geological environments, the advantages of a disposal environment in which the solute transport process is diffusion controlled will be described

  17. Nuclear waste repository simulation experiments (brine migration), Asse Mine of the Federal Republic of Germany: Quarterly brine migration data report, October--December 1985

    International Nuclear Information System (INIS)

    Eckert, J.L.; Kalia, H.N.; Coyle, A.J.

    1988-03-01

    The tenth brine migration data report describes experiments simulating a nuclear waste repository at the 800-m (2624-ft) level of the Asse Salt Mine in the Federal Republic of Germany from May 1983 through December 1985. This report describes the test equipment, the Asse Salt Mine, and the pretest properties of the salt in the test gallery. This report includes test data for 31 months of operations on brine migration rates, borehole pressure, salt temperatures and thermomechanical behavior of the salt. 3 refs., 118 figs., 93 tabs

  18. Quarterly brine migration data report, May-September 1983: Nuclear Waste Repository simulation experiments (brine migration), Asse Mine of the Federal Republic of Germany

    International Nuclear Information System (INIS)

    Coyle, A.J.; Kalia, H.N.; Eckert, J.L.

    1987-04-01

    The first quarterly brine migration data report describes experiments simulating a nuclear waste repository at the 800-m (2624-ft) level of the Asse Salt Mine in the Federal Republic of Germany from May 1983 through September 1983. This report describes the test equipment, the Asse Salt Mine, and the pretest properties of the salt in the test gallery. This report also includes test data for the first 4 months of operations on brine migration rates, borehole pressure, salt temperatures, and thermomechanical behavior of the salt. The duration of the experiments will be approximately 2 years, ending in December 1985. 83 figs., 55 tabs

  19. Theoretical analysis and numerical modelling of heat transfer and fuel migration in underlying soils and constructive elements of nuclear plants during an accident release from the core

    International Nuclear Information System (INIS)

    Arutunjan, R.V.; Bolshov, L.A.; Vitukov, V.V.; Goloviznin, V.M.; Dykhne, A.M.; Kiselev, V.P.; Klementova, S.V.; Krayushkin, I.E.; Moskovchenko, A.V.; Pismennii, V.D.; Popkov, A.G.; Chernov, S.Y.; Chudanov, V.V.; Khoruzhii, O.V.; Yudin, A.I.

    1990-01-01

    Migration of fuel fragments and core fission products during severe accidents on nuclear plants is studied analytically and numerically. The problems of heat transfer and migration of volume heat sources in construction materials and underlying soils are considered

  20. Migration of Older to New Digital Control Systems in Nuclear Power Plant Main Control Rooms

    Energy Technology Data Exchange (ETDEWEB)

    Kovesdi, Casey Robert [Idaho National Lab. (INL), Idaho Falls, ID (United States); Joe, Jeffrey Clark [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-04-01

    The United States (U.S.) Department of Energy (DOE) Office of Nuclear Energy (NE) has the primary mission to advance nuclear power by resolving socio-technical issues through research and development (R&D). One DOE-NE activity supporting this mission is the Light Water Reactor Sustainability (LWRS) program. LWRS has the overall objective to sustain the operation of existing commercial nuclear power plants (NPPs) through conducting R&D across multiple “pathways,” or R&D focus areas. The Advanced Instrumentation, Information, and Control (II&C) Systems Technologies pathway conducts targeted R&D to address aging and reliability concerns with the legacy instrumentation and control (I&C) and related information systems in operating U.S. NPPs. This work involves (1) ensuring that legacy analog II&C systems are not life-limiting issues for the LWR fleet, and (2) implementing digital II&C technology in a manner that enables broad innovation and business improvement in the NPP operating model. Under the LWRS Advanced II&C pathway, Human Factors experts at Idaho National Laboratory (INL) have been conducting R&D in support of NPP main control room (MCR) modernization activities. Work in prior years has focused on migrating analog I&C systems to new digital I&C systems (). In fiscal year 2016 (FY16), one new focus area for this research is migrating older digital I&C systems to new and advanced digital I&C systems. This report summarizes a plan for conducting a digital-to-digital migration of a legacy digital I&C system to a new digital I&C system in support of control room modernization activities.

  1. Migration of Older to New Digital Control Systems in Nuclear Power Plant Main Control Rooms

    International Nuclear Information System (INIS)

    Kovesdi, Casey Robert; Joe, Jeffrey Clark

    2016-01-01

    The United States (U.S.) Department of Energy (DOE) Office of Nuclear Energy (NE) has the primary mission to advance nuclear power by resolving socio-technical issues through research and development (R&D). One DOE-NE activity supporting this mission is the Light Water Reactor Sustainability (LWRS) program. LWRS has the overall objective to sustain the operation of existing commercial nuclear power plants (NPPs) through conducting R&D across multiple ''pathways,'' or R&D focus areas. The Advanced Instrumentation, Information, and Control (II&C) Systems Technologies pathway conducts targeted R&D to address aging and reliability concerns with the legacy instrumentation and control (I&C) and related information systems in operating U.S. NPPs. This work involves (1) ensuring that legacy analog II&C systems are not life-limiting issues for the LWR fleet, and (2) implementing digital II&C technology in a manner that enables broad innovation and business improvement in the NPP operating model. Under the LWRS Advanced II&C pathway, Human Factors experts at Idaho National Laboratory (INL) have been conducting R&D in support of NPP main control room (MCR) modernization activities. Work in prior years has focused on migrating analog I&C systems to new digital I&C systems (). In fiscal year 2016 (FY16), one new focus area for this research is migrating older digital I&C systems to new and advanced digital I&C systems. This report summarizes a plan for conducting a digital-to-digital migration of a legacy digital I&C system to a new digital I&C system in support of control room modernization activities.

  2. Decreased nuclear stiffness via FAK-ERK1/2 signaling is necessary for osteopontin-promoted migration of bone marrow-derived mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Lingling, E-mail: liulingling2012@163.com [Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Luo, Qing, E-mail: qing.luo@cqu.edu.cn [Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Sun, Jinghui, E-mail: sunjhemail@163.com [Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Wang, Aoli, E-mail: leaf13332@163.com [Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Shi, Yisong, E-mail: shiyis@cqu.edu.cn [Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Ju, Yang, E-mail: ju@mech.nagoya-u.ac.jp [Department of Mechanical Science and Engineering, Nagoya University, Nagoya 464-8603 (Japan); Morita, Yasuyuki, E-mail: morita@mech.nagoya-u.ac.jp [Department of Mechanical Science and Engineering, Nagoya University, Nagoya 464-8603 (Japan); Song, Guanbin, E-mail: song@cqu.edu.cn [Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China)

    2017-06-15

    Migration of bone marrow-derived mesenchymal stem cells (BMSCs) plays an important role in many physiological and pathological settings, including wound healing. During the migration of BMSCs through interstitial tissues, the movement of the nucleus must be coordinated with the cytoskeletal dynamics, which in turn affects the cell migration efficiency. Our previous study indicated that osteopontin (OPN) significantly promotes the migration of rat BMSCs. However, the nuclear behaviors and involved molecular mechanisms in OPN-mediated BMSC migration are largely unclear. In the present study, using an atomic force microscope (AFM), we found that OPN could decrease the nuclear stiffness of BMSCs and reduce the expression of lamin A/C, which is the main determinant of nuclear stiffness. Increased lamin A/C expression attenuates BMSC migration by increasing nuclear stiffness. Decreased lamin A/C expression promotes BMSC migration by decreasing nuclear stiffness. Furthermore, OPN promotes BMSC migration by diminishing lamin A/C expression and decreasing nuclear stiffness via the FAK-ERK1/2 signaling pathway. This study provides strong evidence for the role of nuclear mechanics in BMSC migration as well as new insight into the molecular mechanisms of OPN-promoted BMSC migration. - Highlights: • OPN promotes BMSC migration by decreasing nuclear stiffness. • Lamin A/C knockdown decreases, while its overexpression enhances, the nuclear stiffness of BMSCs. • Lamin A/C overexpression and downregulation affect the migration of BMSCs. • OPN diminishes lamin A/C expression and decreases nuclear stiffness through the activation of the FAK-ERK1/2 signaling pathway. • OPN promotes BMSC migration via the FAK-ERK1/2 signaling pathway.

  3. Decreased nuclear stiffness via FAK-ERK1/2 signaling is necessary for osteopontin-promoted migration of bone marrow-derived mesenchymal stem cells

    International Nuclear Information System (INIS)

    Liu, Lingling; Luo, Qing; Sun, Jinghui; Wang, Aoli; Shi, Yisong; Ju, Yang; Morita, Yasuyuki; Song, Guanbin

    2017-01-01

    Migration of bone marrow-derived mesenchymal stem cells (BMSCs) plays an important role in many physiological and pathological settings, including wound healing. During the migration of BMSCs through interstitial tissues, the movement of the nucleus must be coordinated with the cytoskeletal dynamics, which in turn affects the cell migration efficiency. Our previous study indicated that osteopontin (OPN) significantly promotes the migration of rat BMSCs. However, the nuclear behaviors and involved molecular mechanisms in OPN-mediated BMSC migration are largely unclear. In the present study, using an atomic force microscope (AFM), we found that OPN could decrease the nuclear stiffness of BMSCs and reduce the expression of lamin A/C, which is the main determinant of nuclear stiffness. Increased lamin A/C expression attenuates BMSC migration by increasing nuclear stiffness. Decreased lamin A/C expression promotes BMSC migration by decreasing nuclear stiffness. Furthermore, OPN promotes BMSC migration by diminishing lamin A/C expression and decreasing nuclear stiffness via the FAK-ERK1/2 signaling pathway. This study provides strong evidence for the role of nuclear mechanics in BMSC migration as well as new insight into the molecular mechanisms of OPN-promoted BMSC migration. - Highlights: • OPN promotes BMSC migration by decreasing nuclear stiffness. • Lamin A/C knockdown decreases, while its overexpression enhances, the nuclear stiffness of BMSCs. • Lamin A/C overexpression and downregulation affect the migration of BMSCs. • OPN diminishes lamin A/C expression and decreases nuclear stiffness through the activation of the FAK-ERK1/2 signaling pathway. • OPN promotes BMSC migration via the FAK-ERK1/2 signaling pathway.

  4. Distribution and migration of radiocesium in sloping landscapes three years after the Fukushima-1 nuclear accident

    Science.gov (United States)

    Komissarov, M. A.; Ogura, S.

    2017-07-01

    The results of the study are presented on the distribution and migration of radiocesium in mountainous (580-620 m a.s.l.) landscapes in the northeast of Honshu Island (Tohoku Region, Miyagi Prefecture) subjected to radioactive contamination after the nuclear accident at Fukushima-1 NPP. In July 2014, the average contamination density with radiocesium (134Cs and 137Cs) over the territory (150 km to the northwest from NPP) was equal to 16 kBq/m2. This contamination is estimated at the acceptable level according to both Japanese and Russian standards and legislation. Three years after the accident, radiocesium is found to be unevenly distributed by the biogeocenosis components, i.e. 45% in litter, 40% in plants, 10% in soil, and 5% in roots. As for the distribution of total radiocesium (Cs tot = 134Cs + 137Cs) by the profile of volcanic podzolic-ocherous soil ( Dystric Aluandic Andosols), its maximal content (about 80%) was found in the surface layer (0-2.5 cm), with the specific activity ranging from 250 to 10070 Bq/kg and sharply decreasing with the depth. Radiocesium amount in the soils of forest ecosystems was on average by 20% higher than in meadow ecosystems. Accumulation of radionuclides in soils of lower and middle parts of a slope with an insignificant vertical migration was found to be the most general regularity. The air dose rate did not exceed the maximal permissible level, and the snow cover acted as an absorbing and scattering screen.

  5. Studies of nuclear-waste migration in geologic media. Annual report, November 1976--October 1977

    International Nuclear Information System (INIS)

    Seitz, M.G.; Rickert, P.G.; Fried, S.M.; Friedman, A.M.; Steindler, M.J.

    1978-03-01

    The confinement of nuclear wastes in geologic formations is being considered as a method of permanently disposing of the waste. Laboratory experiments (column infiltration, static absorption, and batch partitioning experiments) were performed with nuclides of Cs, Pu, Np, and Am to examine the migratory characteristics of long-lived radionuclides that could be mobilized by groundwaters infiltrating a nuclear waste repository and the surrounding geologic body. In column infiltration experiments, the positions of peak concentrations of Cs in chalk or shale columns; Pu in limestone; Am in limestone, sandstone, or tuff; and Np in a limestone column did not move when the columns were infiltrated with water. However, fractions of each of the nuclides were seen downstream from the peaks, indicating that there was a large dispersion in the relative migration rates of each of the trace elements in the lithic materials studied. The results of static absorption experiments indicate that Pu and Am are strongly absorbed from solution by the common rocks studied and that their migration relative to ground-water flow is thereby retarded. In addition, the reaction rates of dissolved nuclides with rocks were found to vary considerably in different rock-element systems. Batch partitioning experiments were performed to test whether absorption processes are reversible. After granulated basalt and americium-bearing water were contacted in an absorption step, part of the water was replaced with water free of Am and the Am repartitioned between rock and solution. The distribution of Am after desorption was comparable to its distribution after absorption. In cntrast, when tablets of various rocks were allowed to dry between absorption and desorption tests, Pu and Am were not generally desorbed from the tablets. This suggests that reversible reactions of nuclides, between waters and rocks may be upset by treatments such as drying

  6. Nuclear waste repository simulation experiments (brine migration), Asse Mine of the Federal of Germany: Quarterly brine migration data report, July-September 1984

    International Nuclear Information System (INIS)

    Coyle, A.J.; Kalia, H.N.; Eckert, J.L.

    1986-10-01

    The fifth brine migration data status report describes experiments simulating a nuclear waste repository at the 800-m (2624-ft) level of the Asse Salt Mine in the Federal Republic of Germany from May 1983 through September 1984. This report describes the test equipment, the Asse Salt Mine, and the pretest properties of the salt in the test gallery. This report also includes test data for the first 16 months of operations on brine migration rates, borehole pressure, salt temperatures, and thermomechanical behavior of the salt. Annual reports have been prepared for the years 1983 and 1984, describing the test activities on a yearly basis (Rothfuchs et al., 1984, 1986). The duration of the experiments will be approximately 2 years, ending in December 1985. 2 refs., 118 figs., 91 tabs

  7. Zyxin regulates migration of renal epithelial cells through activation of hepatocyte nuclear factor-1β.

    Science.gov (United States)

    Choi, Yun-Hee; McNally, Brian T; Igarashi, Peter

    2013-07-01

    Hepatocyte nuclear factor-1β (HNF-1β) is an epithelial tissue-specific transcription factor that regulates gene expression in the kidney, liver, pancreas, intestine, and other organs. Mutations of HNF-1β in humans produce renal cysts and congenital kidney anomalies. Here, we identify the LIM-domain protein zyxin as a novel binding partner of HNF-1β in renal epithelial cells. Zyxin shuttles to the nucleus where it colocalizes with HNF-1β. Immunoprecipitation of zyxin in leptomycin B-treated cells results in coprecipitation of HNF-1β. The protein interaction requires the second LIM domain of zyxin and two distinct domains of HNF-1β. Overexpression of zyxin stimulates the transcriptional activity of HNF-1β, whereas small interfering RNA silencing of zyxin inhibits HNF-1β-dependent transcription. Epidermal growth factor (EGF) induces translocation of zyxin into the nucleus and stimulates HNF-1β-dependent promoter activity. The EGF-mediated nuclear translocation of zyxin requires activation of Akt. Expression of dominant-negative mutant HNF-1β, knockdown of zyxin, or inhibition of Akt inhibits EGF-stimulated cell migration. These findings reveal a novel pathway by which extracellular signals are transmitted to the nucleus to regulate the activity of a transcription factor that is essential for renal epithelial differentiation.

  8. Investigation of migration an actinide imitator (Ce) in synthesis glass ceramics with a nuclear microscope

    International Nuclear Information System (INIS)

    Bondarenko, V.N.; Goncharov, A.V.; Odejchuk, M.A.; Pistryak, V.M.; Pilipenko, A.V.; Sank, S.Yu.; Sukhostaeva, V.I.; Shevstiev, A.P.

    2005-01-01

    Full text: The generally accepted conception of radioactive waste (RAW) safe disposal, so-called 'multibarrier strategy', assumes construction of several protective barriers in a geologic burial. One of these barriers is is a durable corrosion-resistant container of RAW. The glass ceramics (syntetic alumina silicate) is considered as promising material for such containers. An important parameter for long term reduction of behavior for such materials is rate of radionuclide emanation from the container. As an element whose migration in solids is analogous as that of actinide, one generally uses Cerium. For investigation of transuranium element migration Ce is used as an analogue. Accordingly, CeO 2 may serve as an imitator of transuranium oxides. In the present work Ce migration in glass ceramics has been investigated with a nuclear microprobe which is more sensitive instrument than an electron microscope. The glass ceramic material was prepared from mixture of materials powders (70 % mas. of red granite and 30% mas. of kaolin) by sintering under pressure. The hot pressing was conducted at 1050 deg. temperature and 40 MPa pressure. The endurance time continued 15 min. Manufactured alumina silicate samples were in the form of a pellet. The material density was 2.5-2.7 g/cm 3 . Pellets of imitator substance were made of CeO 2 powder by the same method. After polishing, aluminosilicate and imitator pellets were pressed together and annealed in the temperature range from 600 to 750 deg. C in vacuum during 10 hours. As a result of annealing, Ce penetration occurred thought the interface into the depth of the alumina silicate pellet. After that the pellets were separated, and the alumina silicate pellet was cleaved in the direction transversal to the former interface. The surface of cleavage of alumina silicate pellet was studied with a nuclear microprobe. For measurement of Ce diffusion distribution in alumina silicate samples we applied a nuclear microprobe on the basis

  9. Strategy for Migration of Traditional to Hybrid Control Boards in a Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Boring, Ronald Laurids [Idaho National Lab. (INL), Idaho Falls, ID (United States); Joe, Jeffrey Clark [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ulrich, Thomas Anthony [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-07-01

    This strategy document describes the NUREG-0711 based human factors engineering (HFE) phases and associated elements required to support design, verification and validation (V&V), and implementation of new digital control room elements in a legacy analog main control room (MCR). Information from previous planning and analysis work serves as the foundation for creating a human-machine interface (HMI) specification for distributed control systems (DCSs) to be implemented as part of nuclear power plant (NPP) modernization. This document reviews ways to take the HMSI specification and use it when migrating legacy displays or designing displays with new functionality. These displays undergo iterative usability testing during the design phase and then an integrated system validation (ISV) in the full-scope control room training simulator. Following successful demonstration of operator performance using the systems during the ISV, the new DCS is implemented at the plant, first in the training simulator and then in the MCR. This document concludes with a sample project plan, including a 15-month timeline from DCS design through implementation. Included is a discussion of how the U.S. Department of Energy’s Human System Simulation Laboratory (HSSL) can be used to support design and V&V activities. This report completes a Level 4 (M4) milestone under the U.S. Department of Energy’s (DOE’s) Light Water Reactor Sustainability (LWRS) Program.

  10. Brine: a computer program to compute brine migration adjacent to a nuclear waste canister in a salt repository

    International Nuclear Information System (INIS)

    Duckworth, G.D.; Fuller, M.E.

    1980-01-01

    This report presents a mathematical model used to predict brine migration toward a nuclear waste canister in a bedded salt repository. The mathematical model is implemented in a computer program called BRINE. The program is written in FORTRAN and executes in the batch mode on a CDC 7600. A description of the program input requirements and output available is included. Samples of input and output are given

  11. 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

  12. 137Cs vertical migration in a deciduous forest soil following the Fukushima Dai-ichi Nuclear Power Plant accident

    International Nuclear Information System (INIS)

    Nakanishi, Takahiro; Matsunaga, Takeshi; Koarashi, Jun; Atarashi-Andoh, Mariko

    2014-01-01

    The large amount of 137 Cs deposited on the forest floor because of the Fukushima Dai-ichi Nuclear Power Plant accident represents a major potential long-term source for mobile 137 Cs. To investigate 137 Cs mobility in forest soils, we investigated the vertical migration of 137 Cs through seepage water, using a lysimetric method. The study was conducted in a deciduous forest soil over a period spanning 2 month to 2 y after the Fukushima nuclear accident. Our observations demonstrated that the major part of 137 Cs in the litter layer moved into the mineral soil within one year after the accident. On the other hand, the topsoil prevented migration of 137 Cs, and only 2% of 137 Cs in the leachate from litter and humus layer penetrated below a 10 cm depth. The annual migration below a 10 cm depth accounted for 0.1% of the total 137 Cs inventory. Therefore, the migration of 137 Cs by seepage water comprised only a very small part of the total 137 Cs inventory in the mineral soil, which was undetectable from the vertical distribution of 137 Cs in the soil profile. In the present and immediate future, most of the 137 Cs deposited on the forest floor will probably remain in the topsoil successively, although a small but certain amount of bioavailable 137 Cs exists in forest surface soil. -- Highlights: • Lysimeter captured 137 Cs mobility in a forest soil after the Fukushima accident. • Major part of 137 Cs in the litter layer moved into the mineral soil within a year. • Litter-leachate 137 Cs was predominantly adsorbed within the topsoil. • The annual migration below a 10 cm depth was 0.1% of the total 137 Cs inventory

  13. Studies of nuclear-waste migration in geologic media. Annual report, October 1977-September 1978

    International Nuclear Information System (INIS)

    Seitz, M.G.; Rickert, P.G.; Fried, S.M.; Friedman, A.M.; Steindler, M.J.

    1979-07-01

    The first phenomenon studied is incomplete water-nuclide-rock reaction because of slow reaction kinetics. A kinetic factor derived from the experimental results for strontium migration through glauconite (a hydrous silicate) was expressed in terms of the linear flow rate of solution and can be used to predict migration due to solution flow at rates of 0 to about 12 cm/min (60 km/y). Continuous-flow infiltration experiments with americium in fissures gave results that are predicted by a migration model that includes kinetic factors measured in experiments with static fluids. The results suggest that kinetic factors are as important as equilibrium adsorption parameters in predicting nuclide migration. The second phenomenon studied was the amount of adsorbed nuclide not being proportional to the nuclide concentration in solution (nonlinear adsorption isotherm). For cesium adsorption on limestone, a nonlinear isotherm was found to occur in the range of initial cesium concentrations from about 10 -3 to 10 -9 M. This adsorption property was confirmed by results of column-infiltration experiments in which cesium migration through oolitic limestone was found to be sensitive to the amount of cesium in solution. The existence of a nonlinear isotherm precludes the use of a single partition value (K/sub D/) to describe cesium migration in limestone at cesium concentrations above about 10 -9 M. Therefore, the effects of nonlinear isotherms are germane to nuclide migration. 24 figures, 6 tables

  14. Subject-3: Study on migration of radionuclides released into terrestrial and aquatic environment after nuclear accident

    International Nuclear Information System (INIS)

    Amano, H.; Matsunaga, T.; Ueno, T.; Nagao, S.; Yanase, N.; Tkachenko, Yu.

    2001-01-01

    Subject-3 has been focused on the migration behavior of long-lived radionuclides in the terrestrial surface environment, especially in connection with their chemical and physical forms. Migration behavior of radionuclides is strongly affected with their chemical and physical forms (for example; Gunten and Benes 1995). One of the two categories in Subject-3 consists of migration from surface soils including aging effects of hot particles, plant uptake from contaminated soils, and resuspension of radionuclides. The other is run off by river system, considering the role of organic materials. (author)

  15. Subject-3: Study on migration of radionuclides released into terrestrial and aquatic environment after nuclear accident

    Energy Technology Data Exchange (ETDEWEB)

    Amano, H.; Matsunaga, T.; Ueno, T.; Nagao, S.; Yanase, N. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Arkhipov, A.N. [Chernobyl Scientific and Technical Center for International Research (Ukraine); Tkachenko, Yu. [The State Enterprise Regional Monitoring and Domestic Control (RADEC) (Unknown)

    2001-03-01

    Subject-3 has been focused on the migration behavior of long-lived radionuclides in the terrestrial surface environment, especially in connection with their chemical and physical forms. Migration behavior of radionuclides is strongly affected with their chemical and physical forms (for example; Gunten and Benes 1995). One of the two categories in Subject-3 consists of migration from surface soils including aging effects of hot particles, plant uptake from contaminated soils, and resuspension of radionuclides. The other is run off by river system, considering the role of organic materials. (author)

  16. Studies of nuclear waste migration in geologic media. Annual report, October 1978-September 1979

    International Nuclear Information System (INIS)

    Seitz, M.G.; Rickert, P.G.; Couture, R.A.; Williams, J.; Meldgin, N.; Fried, S.M.; Friedman, A.M.; Steindler, M.J.

    1980-01-01

    Experimental results obtained this year confirm the results obtained in previous years - that nuclides migrating by fluid flow in rock often exhibit complex behavior not predicted by simple chromatographic-type models. A phenomenon found previously to lead to complex behavior for leached radionuclides is that the amount of adsorbed nuclide was not proportional to the nuclide concentration in solution (nonlinear adsorption isotherm). For cesium adsorption on limestone and on basalt, nonlinear isotherms were found this year to occur in the range of cesium concentrations in the groundwater of about 10 -3 to 10 -9 M. Because cesium concentrations in this range can readily be attained by the leaching of solid waste by groundwater, the effects of nonlinear isotherms are germane to nuclide migration. This dependence of cesium migration on the leached concentration of cesium emphasizes the importance of treating the leaching and migration processes simultaneously such as is done in the leach-migration experiments performed in this work. The existence of nonlinear isotherms precludes the use of a single partition coefficient (K/sub d/) to describe cesium migration at an arbitrary cesium concentration above 10 -9 M. Nonetheless, nonlinear isotherms can be studied experimentally (e.g., to give K/sub d/ as a function of concentration) and effects of nonlinear adsorption can be predicted quantitatively. Comparison of results from column and batch tests indicate that, in addition to nonlinear adsorption, kinetic effects need to be considered in predicting nuclide migration from the partition coefficients measured in batch tests. Results of batch experiments of 2 weeks or longer duration pertained to migration expected only at the very lowest (< 50 m/y) groundwater flow rates of interest

  17. STK35L1 associates with nuclear actin and regulates cell cycle and migration of endothelial cells.

    Directory of Open Access Journals (Sweden)

    Pankaj Goyal

    Full Text Available BACKGROUND: Migration and proliferation of vascular endothelial cells are essential for repair of injured endothelium and angiogenesis. Cyclins, cyclin-dependent kinases (CDKs, and cyclin-dependent kinase inhibitors play an important role in vascular tissue injury and wound healing. Previous studies suggest a link between the cell cycle and cell migration: cells present in the G(1 phase have the highest potential to migrate. The molecular mechanism linking these two processes is not understood. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we explored the function of STK35L1, a novel Ser/Thr kinase, localized in the nucleus and nucleolus of endothelial cells. Molecular biological analysis identified a bipartite nuclear localization signal, and nucleolar localization sequences in the N-terminal part of STK35L1. Nuclear actin was identified as a novel binding partner of STK35L1. A class III PDZ binding domains motif was identified in STK35L1 that mediated its interaction with actin. Depletion of STK35L1 by siRNA lead to an accelerated G(1 to S phase transition after serum-stimulation of endothelial cells indicating an inhibitory role of the kinase in G(1 to S phase progression. Cell cycle specific genes array analysis revealed that one gene was prominently downregulated (8.8 fold in STK35L1 silenced cells: CDKN2A alpha transcript, which codes for p16(INK4a leading to G(1 arrest by inhibition of CDK4/6. Moreover in endothelial cells seeded on Matrigel, STK35L1 expression was rapidly upregulated, and silencing of STK35L1 drastically inhibited endothelial sprouting that is required for angiogenesis. Furthermore, STK35L1 depletion profoundly impaired endothelial cell migration in two wound healing assays. CONCLUSION/SIGNIFICANCE: The results indicate that by regulating CDKN2A and inhibiting G1- to S-phase transition STK35L1 may act as a central kinase linking the cell cycle and migration of endothelial cells. The interaction of STK35L1 with nuclear

  18. Radionuclide migration experiments related to an underground nuclear test: II. modeling studies

    International Nuclear Information System (INIS)

    Tompson, A.; Carle, S.F.; Smith, D.K.; Hudson, G.B.; Bruton, C.J.

    2001-01-01

    Full text: The goal of this project is to improve our understanding of water and radionuclide migration in both saturated and unsaturated geologic media by coupling advanced simulation techniques, available characterization data, and radioanalytical measurements in the context of a remarkable field experiment. Between 1975 and 1991, groundwater was steadily pumped from a well adjacent to a 1965 underground test conducted in alluvium at the Nevada Test Site. The experiment was primarily conducted in order to elicit information on radionuclide migration through the saturated zone between the test and the well. The effluent was monitored. discharged to an unlined ditch, and allowed to infiltrate into the ground during flow towards a dry lake, about a kilometer away. The 16 years of pumping and infiltration created an unexpected second experiment in which the migration of the ditch effluent through the 200 meters of unsaturated media, back to the water table, could be studied. Pumping and effluent data are being utilized in conjunction with chemical measurements made in groundwater and a series of numerical models to better understand the movement of radionuclides in the system, both between the test and the well, and between the ditch and the water table. The release of radionuclides away from a testing area will be controlled by local groundwater flow rates, by their dissolution from solidified melt glass produced by the test, and by chemical sorption processes that retard their migration rates in chemically reactive geologic media. Only the more mobile and less reactive radionuclides (e.g.. tritium, 14 C, 36 Cl, 85 Kr, and 129 I) were measured in the well effluent. The movement of these radionuclides through the unsaturated media beneath the ditch will be affected additionally by the capillary nature of moisture movement under unsaturated conditions and by their interaction with and potential mass exchange with the gas (air) phase. Results of numerical simulations

  19. Study on radionuclide migration through a buffer material of the repository for high level nuclear waste

    International Nuclear Information System (INIS)

    Tsukamoto, Masaki; Ohe, Toshiaki

    1989-01-01

    The present report discusses radionuclide migration through a buffer material from the view point of experimental and data analysis. Na-bentonite loosely compacted with dry density of 0.8 - 1 g/cm 3 was contacted with cesium chloride solution of about 100 ppb containing Cs-134 as a tracer at 40degC and at 70degC. After the experiments, the bentonite cake was sliced and cesium distribution in the cake was measured by gamma-spectrometry. Apparent diffusivities of 2∼5 x 10 -7 cm 2 /sec was determined through the analysis method where pore diffusion and adsorption were involved. Numerical solution well described the observed data. The pore diffusion would be clearfied to be a dominant mechanism of the radionuclide migration in the bentonite, through discussing the pore diffusion mechanism and activation energy of the diffusion. This report also discusses the capability of the chemical transport model CHEMTRN for long-term predictions of the radionuclide migration. (author)

  20. Radionuclide Migration at the Rio Blanco Site, A Nuclear-stimulated Low-permeability Natural Gas Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Clay A. Cooper; Ming Ye; Jenny Chapman; Craig Shirley

    2005-10-01

    The U.S. Department of Energy and its predecessor agencies conducted a program in the 1960s and 1970s that evaluated technology for the nuclear stimulation of low-permeability gas reservoirs. The third and final project in the program, Project Rio Blanco, was conducted in Rio Blanco County, in northwestern Colorado. In this experiment, three 33-kiloton nuclear explosives were simultaneously detonated in a single emplacement well in the Mesaverde Group and Fort Union Formation, at depths of 1,780, 1,899, and 2,039 m below land surface on May 17, 1973. The objective of this work is to estimate lateral distances that tritium released from the detonations may have traveled in the subsurface and evaluate the possible effect of postulated natural-gas development on radionuclide migration. Other radionuclides were considered in the analysis, but the majority occur in relatively immobile forms (such as nuclear melt glass). Of the radionuclides present in the gas phase, tritium dominates in terms of quantity of radioactivity in the long term and contribution to possible whole body exposure. One simulation is performed for {sup 85}Kr, the second most abundant gaseous radionuclide produced after tritium.

  1. Cat-Scan and nuclear magnetic resonance imaging in abnormalities of neuronal migration

    International Nuclear Information System (INIS)

    Wilms, G.; Marchal, G.; Decrop, E.; Van Hecke, P.; Baert, A.L.; Casaer, P.

    1989-01-01

    This is a report of the CAT-scan and MRI characteristics in 14 patients with anomalies of neuronal migration. There were 3 cases of heterotopia of the gray matter, 2 cases of agyria, 3 cases of pachygyria, 2 cases of schizencephaly and 4 cases of hemimegalencephaly. The primary advantages of MRI in comparison with CAT-scanning, are better contrast between the white and gray matter; better delineation of the cerebral cortex and the possibility of direct mutiplanar imaging. NMRI will become the investigation of choice in children with epilepsy or psychomotor retardation [fr

  2. Study on water migration of tunnel surrounding rock in nuclear waste repository based on coupling theory

    International Nuclear Information System (INIS)

    Jiang Zhongming; Zhang Xinmin

    2008-01-01

    Excavation of tunnel changes not only the stresses and deformation of tunnel surrounding rock, but also disturbs the underground water environment in tunnel surrounding rock Water migration happens due to variation of pore water pressure and redistribution. Based on the mechanics of porous media, saturated and unsaturated hydro-mechanical coupling analysis method is employed to study the variation of the stresses, deformation and pore pressure of the surrounding rock. Case study indicates that the excavation of tunnel will induce redistribution of stress and pore water pressure. Redistribution of pore water pressure will seriously affect on evaluation of surrounding rock stability and diffusion of nucleon in the pore water. (authors)

  3. Migrations of 60-Co and 137-Cs in Saturated and unsaturated Soil at Serpong Nuclear Research Center

    International Nuclear Information System (INIS)

    Lubis, E; Untara

    1996-01-01

    The migrations of 60-Co and 137-Cs in saturated and unsaturated soil at Serpong Nuclear Research Center was investigated. The objectives of this investigation are to find the geological and hydrological parameters, especially for estimating the migrations of radionuclides in porous media with advection-dispersion equations. The result showed that the porosity (η) and density (ρ ) of saturated soil are 27.6% and 1.35 g/cm3, and in the unsaturated soil are 18.9% and 1.41 g/cm3. The coefficients distributions (Kd) of 60-Co and 137-Cs in saturated and unsaturated soil are 1.6 - 8.9 and 3.2 - 7.7 respectively. The hydrodinamic coefficients (Dx) and dispersivity (αx) of C0-60 in saturated and unsaturated soil are 0.85 cm2/second and 2.4 x 10-3 cm, and for 137-Cs are 0.91 cm2/second and 2.54 x 10E3 cm

  4. TYBO/BENHAM: Model Analysis of Groundwater Flow and Radionuclide Migration from Underground Nuclear Tests in Southwestern Pahute Mesa, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Andrew Wolfsberg; Lee Glascoe; Guoping Lu; Alyssa Olson; Peter Lichtner; Maureen McGraw; Terry Cherry; Guy Roemer

    2002-09-01

    Recent field studies have led to the discovery of trace quantities of plutonium originating from the BENHAM underground nuclear test in two groundwater observation wells on Pahute Mesa at the Nevada Test Site. These observation wells are located 1.3 km from the BENHAM underground nuclear test and approximately 300 m from the TYBO underground nuclear test. In addition to plutonium, several other conservative (e.g. tritium) and reactive (e.g. cesium) radionuclides were found in both observation wells. The highest radionuclide concentrations were found in a well sampling a welded tuff aquifer more than 500m above the BENHAM emplacement depth. These measurements have prompted additional investigations to ascertain the mechanisms, processes, and conditions affecting subsurface radionuclide transport in Pahute Mesa groundwater. This report describes an integrated modeling approach used to simulate groundwater flow, radionuclide source release, and radionuclide transport near the BENHAM and TYBO underground nuclear tests on Pahute Mesa. The components of the model include a flow model at a scale large enough to encompass many wells for calibration, a source-term model capable of predicting radionuclide releases to aquifers following complex processes associated with nonisothermal flow and glass dissolution, and site-scale transport models that consider migration of solutes and colloids in fractured volcanic rock. Although multiple modeling components contribute to the methodology presented in this report, they are coupled and yield results consistent with laboratory and field observations. Additionally, sensitivity analyses are conducted to provide insight into the relative importance of uncertainty ranges in the transport parameters.

  5. Downward migration of radiocesium in an abandoned paddy soil after the Fukushima Dai-ichi Nuclear Power Plant accident.

    Science.gov (United States)

    Takahashi, Junko; Wakabayashi, Shokichi; Tamura, Kenji; Onda, Yuichi

    2018-02-01

    After the Fukushima Dai-ichi Nuclear Power Plant accident on March 2011, continuous monitoring of the detailed vertical distribution of radiocesium in soil is required to evaluate the fate of radiocesium and establish strategies for remediation and management of the contaminated land. It is especially important to investigate paddy soil because little knowledge has been accumulated for paddy soil and wetland rice is a major staple in Japan. Therefore, we monitored the vertical distribution of 137 Cs in abandoned paddy soil in a planned evacuation zone from June 2011 to March 2016. The decontamination works (i.e., 5 cm of surface soil removal and re-covering with uncontaminated soil) were conducted by the government in 2015. As a result of monitoring, the 137 Cs gradually migrated downward with time and the 137 Cs concentration in the 0-10 cm soil was almost homogenous in October 2014, although it was non-cultivated. The liner relationship was obtained between the median depth, which is the thickness of a soil layer containing half of the total 137 Cs inventory, and the time after the accident, indicating the migration rate was constant (1.3 cm y -1 ) before the decontamination works. After the decontamination works, the 137 Cs concentration in the uppermost surface layer was reduced by 90%, however the total 137 Cs inventory was reduced by only 50-70%. It was shown that the efficiency of 137 Cs removal by the decontamination works decrease linearly over time in fields like the studied paddy, in which the homogenization of 137 Cs concentration occurred. Conversely, the downward migration of 137 Cs to subsurface layers deeper than 10 cm (i.e., plowpan layer) with low permeability rarely occurred. It is expected that these unique trends in distribution and migration of 137 Cs would be found in abandoned paddy soils with properties similar to the studied soil, sandy loam but poorly drained because of the low permeable plowpan layer, although further validation is

  6. Local traction force in the proximal leading process triggers nuclear translocation during neuronal migration.

    Science.gov (United States)

    Umeshima, Hiroki; Nomura, Ken-Ichi; Yoshikawa, Shuhei; Hörning, Marcel; Tanaka, Motomu; Sakuma, Shinya; Arai, Fumihito; Kaneko, Makoto; Kengaku, Mineko

    2018-04-05

    Somal translocation in long bipolar neurons is regulated by actomyosin contractile forces, yet the precise spatiotemporal sites of force generation are unknown. Here we investigate the force dynamics generated during somal translocation using traction force microscopy. Neurons with a short leading process generated a traction force in the growth cone and counteracting forces in the leading and trailing processes. In contrast, neurons with a long leading process generated a force dipole with opposing traction forces in the proximal leading process during nuclear translocation. Transient accumulation of actin filaments was observed at the dipole center of the two opposing forces, which was abolished by inhibition of myosin II activity. A swelling in the leading process emerged and generated a traction force that pulled the nucleus when nuclear translocation was physically hampered. The traction force in the leading process swelling was uncoupled from somal translocation in neurons expressing a dominant negative mutant of the KASH protein, which disrupts the interaction between cytoskeletal components and the nuclear envelope. Our results suggest that the leading process is the site of generation of actomyosin-dependent traction force in long bipolar neurons, and that the traction force is transmitted to the nucleus via KASH proteins. Copyright © 2018 Elsevier B.V. and Japan Neuroscience Society. All rights reserved.

  7. A review of a field study of radionuclide migration from an underground nuclear explosion at the Nevada Test Site

    International Nuclear Information System (INIS)

    Hoffman, D.C.; Daniels, W.R.; Wolfsberg, K.; Thompson, J.L.; Rundberg, R.S.; Fraser, S.L.; Daniels, K.S.

    1984-01-01

    Results from a long-term (9 year) field study of the distribution of radionuclides around an underground nuclear explosion cavity at the Nevada Test Site are reviewed. The goals of this Radionuclide Migration project are to examine the rates of migration underground in various media and to determine the potential for movement, both on and off the Nevada Test Site, of radioactivity from such explosions, with particular interest in possible contamination of water supplies. Initial studies were undertaken near the site of the low-yield test Cambric, which was detonated 73 m beneath the water table in tuffaceous alluvium. Solid samples were obtained from just below ground surface to 50 m below the detonation point, and water was sampled from five different regions in the vicinity of the explosion. Ten years after the test, most of the radioactivity was found to be retained in the fused debris in the cavity region and no activity above background was found 50 m below. Only tritium and 90 Sr were present in water in the cavity at levels greater than recommended concentration guides for water in uncontrolled areas. A satellite well is being used to remove water 91 m from the detonation point. During seven years (7x10 6 m 3 ) of pumping, tritium, 85 Kr, 36 Cl and 129 I have been detected in the water. Approximately 40% of the total tritium from the cavity region has been removed by pumping at the satellite well, and the maximum in the tritium concentration is clearly defined. Use of sensitive analytical techniques has permitted measurement of the very low concentrations of 36 Cl and 129 I present in the water. The 36 Cl peak precedes the tritiated water, possibly as a result of anion exclusion. Additional analyses are in progress to better define the shape of the 129 I concentration curve. (author)

  8. Review of a field study of radionuclide migration from an underground nuclear explosion at the Nevada Test Site

    International Nuclear Information System (INIS)

    Hoffman, D.C.; Daniels, W.R.; Wolfsberg, K.; Thompson, J.L.; Rundberg, R.S.; Fraser, S.L.; Daniels, K.S.

    1983-01-01

    Results from a long-term (9 year) field study of the distribution of radionuclides around an underground nuclear explosion cavity at the Nevada Test Site are reviewed. The goals of this Radionuclide Migration project are to examine the rates of migration underground in various media and to determine the potential for movement, both on and off the Nevada Test Site, of radioactivity from such explosions, with particular interest in possible contamination of water supplies. Initial studies were undertaken near the site of the low-yield test Cambric, which was detonated 73 m beneath the water table in tuffaceous alluvium. Solid samples were obtained from just below ground surface to 50 m below the detonation point, and water was sampled from five different regions in the vicinity of the explosion. Ten years after the test, most of the radioactivity was found to be retained in the fused debris in the cavity region and no activity above background was found 50 m below. Only tritium and 90 Sr were presented in water in the cavity at levels greater than recommended concentration guides for water in uncontrolled areas. A satellite well is being used to remove water 91 m from the detonation point. During seven years (7 x 10 6 m 3 ) of pumping, tritium, 85 Kr, 36 Cl, and 129 I have been detected in the water. Approximately 40% of the total tritium from the cavity region has been removed by pumping at the satellite well, and the maximum in the tritium concentration is clearly defined. Use of sensitive analytical techniques has permitted measurement of the very low concentrations of 36 Cl and 129 I present in the water. The 36 Cl peak precedes the tritiated water, possibly as a result of anion exclusion. Additional analyses are in progress to better define the shape of the 129 I concentration curve

  9. Matrix metalloproteinase 12 is induced by heterogeneous nuclear ribonucleoprotein K and promotes migration and invasion in nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Chung, I-Che; Li, Hsin-Pai; Chang, Yu-Sun; Chen, Lih-Chyang; Chung, An-Ko; Chao, Mei; Huang, Hsin-Yi; Hsueh, Chuen; Tsang, Ngan-Ming; Chang, Kai-Ping; Liang, Ying

    2014-01-01

    Overexpression of heterogeneous nuclear ribonucleoprotein K (hnRNP K), a DNA/RNA binding protein, is associated with metastasis in nasopharyngeal carcinoma (NPC). However, the mechanisms underlying hnRNP K-mediated metastasis is unclear. The aim of the present study was to determine the role of matrix metalloproteinase (MMP) in hnRNP K-mediated metastasis in NPC. We studied hnRNP K-regulated MMPs by analyzing the expression profiles of MMP family genes in NPC tissues and hnRNP K-knockdown NPC cells using Affymetrix microarray analysis and quantitative RT-PCR. The association of hnRNP K and MMP12 expression in 82 clinically proven NPC cases was determined by immunohistochemical analysis. The hnRNP K-mediated MMP12 regulation was determined by zymography and Western blot, as well as by promoter, DNA pull-down and chromatin immunoprecipitation (ChIP) assays. The functional role of MMP12 in cell migration and invasion was demonstrated by MMP12-knockdown and the treatment of MMP12-specific inhibitor, PF-356231. MMP12 was overexpressed in NPC tissues, and this high level of expression was significantly correlated with high-level expression of hnRNP K (P = 0.026). The levels of mRNA, protein and enzyme activity of MMP12 were reduced in hnRNP K-knockdown NPC cells. HnRNP K interacting with the region spanning −42 to −33 bp of the transcription start site triggered transcriptional activation of the MMP12 promoter. Furthermore, inhibiting MMP12 by MMP12 knockdown and MMP12-specific inhibitor, PF-356231, significantly reduced the migration and invasion of NPC cells. Overexpression of MMP12 was significantly correlated with hnRNP K in NPC tissues. HnRNP K can induce MMP12 expression and enzyme activity through activating MMP12 promoter, which promotes cell migration and invasion in NPC cells. In vitro experiments suggest that NPC metastasis with high MMP12 expression may be treated with PF-356231. HnRNP K and MMP12 may be potential therapeutic markers for NPC, but

  10. Migration of the UNIX Application for eFAST CANDU Nuclear Power Plant Analyzer

    International Nuclear Information System (INIS)

    Suh, Jae Seung; Sohn, Dae Seong; Kim, Sang Jae; Jeun, Gyoo Dong

    2006-01-01

    Since the mid 1980s, corporate data centers have been moving away from mainframes running dedicated operating systems to mini-computers, often using one or other of the myriad flavors of UNIX. At the same time, the users' experience of these systems has, in many cases, stayed the same, involving text-based interaction with dumb terminals or a terminal-emulation session on a Personal Computer. More recently, IT managers have questioned this approach, and have been looking at changes in the UNIX marketplace and the increasing expense of being tied in to single-vendor software and hardware solutions. The growth of Linux as a lightweight version of UNIX has fueled this interest, raising the number of organizations that are considering a migration to alternative platforms. The various implementations of the UNIX operating system have served industry well, as witnessed by the very large base both of installed systems and large-scale applications installed on those systems. However, there are increasing signs of dissatisfaction with expensive, often proprietary solutions and a growing sense that perhaps the concept of 'big iron' has had its day in the same way as it has for most of the mainframes of the type portrayed in 1970s science fiction films. One of the most extraordinary and unexpected successes of the Intel PC architecture is the extent to which this basic framework has been extended to encompass very large server and data center environments. Large-scale hosting companies are now offering enterprise level services to multiple client companies at availability levels of over 99.99 percent on what are simply racks of relatively cheap PCs. Technologies such as clustering, Network Load Balancing, and Component Load Balancing enable the personal computer to take on and match the levels of throughput, availability, and reliability of all but the most expensive 'big iron' solutions and the supercomputers

  11. Simulation of Groundwater Flow and Migration of the Radioactive Cobalt-60 from LAMA Nuclear Facility-Iraq

    Directory of Open Access Journals (Sweden)

    Thair Sharif Khayyun

    2018-02-01

    Full Text Available This study provides a simulation of groundwater flow and advective-dispersive migration of radioactive Co-60 through an aquifer with three layers, which release or leak to groundwater from the Active Metallurgy Testing Laboratory (LAMA Nuclear Facility-Iraq due to the nuclear accident scenario. Processing Modflow for windows (PMWIN and Modular Three-Dimensional Multispecies Transport (MT3DMS Models were used for this purpose. The study area and the contaminated area were 12.7 km2 and 0.005625 km2, respectively. Water levels of the groundwater have been measured in six monitoring wells. The simulation time was assumed to have started in 2016. The PMWIN model simulated the flow for two scenarios of water level in Tigris River (average and minimum water levels. The MT3DMS model simulated 10 years of plume travel, beginning in 2016. The simulated Co-60 concentrations after five years of travel were 32.34 and 34.44 μg/m3 for the two scenarios. The maximum predicted Co-60 concentrations at the end of Year 10 were 34.86 and 37.31 μg/m3, respectively. The sensitivity analysis showed that the simulated hydraulic heads in the observation wells and the simulated plume of Co-60 were highly sensitive to changes in the effective porosity but less sensitive to changes in other parameters of the dispersion and chemical reaction processes. The time necessary to reach steady state condition was predicted to be approximately 16 years. The contaminated area was isolated by using remedial process which is represented by three fully penetrating pumping wells with a suitable flow rate (0.045 m3/s for controlling the movement of Co-60 pollutant.

  12. Radiation-Driven Migration: The Case of Minamisoma City, Fukushima, Japan, after the Fukushima Nuclear Accident

    Directory of Open Access Journals (Sweden)

    Hui Zhang

    2014-09-01

    Full Text Available The emigration of residents following the Fukushima nuclear accident has resulted in aging and depopulation problems in radiation-contaminated areas. The recovery of affected areas, and even those areas with low radioactive pollution levels, is still heavily affected by this problem. This slow recovery consequently affects immigration patterns. This review aims to present possible factors that have contributed to this dilemma. We first present an overview of the evacuation protocol that was administered in the study area following the Fukushima accident. We then analyze characteristics of the subsequent exodus by comparing population data for both before and after the accident. Based on the findings of existing literature, we identify three causes of emigration: (1 The health risks of living in a low radiation zone are still unknown; (2 The post-disaster psychological disturbance and distrust of government information promotes the emigration of evacuees; (3 an absence of economic vitality and of a leading industry renders the area less attractive to individuals residing outside of the city. Further research is needed on this issue, especially with respect to countermeasures for addressing this problem.

  13. Hydrogeochemical processes affecting the migration of radionuclides in a fluvial sand aquifer at the Chalk River Nuclear Laboratories

    International Nuclear Information System (INIS)

    Jackson, R.E.; Inch, K.J.

    1980-01-01

    In the mid-1950's two experimental disposals of liquid radioactive waste containing about 700 curries of strontium-90 and cesium-137 were made into pits in sandy ground at one of the disposal areas at Chalk River Nuclear Laboratories. Since then, the wastes have migrated into two nearby aquifers and have chromatographically separated into strontium-90 and cesium-137 plumes moving at velocities less than that of the transporting groundwater. Analysis of radioactively contaminated aquifer sediments showed that most of the strontium-90 is exchangeably adsorbed, primarily to feldspars and layer silicates (mainly biotite); the rest is either specifically adsorbed to iron (III) and perhaps manganese (IV) oxhydroxides or fixed to unknown sinks. Less than one half of adsorbed cesium-137 is exchangeable with 0.5 m calcium chloride; the high levels of cesium-137 adsorption and fixation are probably due to its reaction with micaceous minerals. Complexation of strontium-90 and cesium-137 does not appear to be an important factor affecting their transport or adsorption. In studies of groundwater quality or pollution, dissolved oxygen and sulfide should be measured in addition to the redox potential since it allows independent assessment of the redox levels. The latter were found to affect the mobility of multivalent transition metals and nonmetals. (DN)

  14. The study of the dynamics of migration main radiologically significant isotopes in the near and far field Chernobyl nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Bondarkov, M.; Bondarkov, D.; Maksymenko, A. [Chornobyl Center for Nuclear Safety, Radioactive Waste and Radioecology (Ukraine); Zheltonozhskaya, M.; Zheltonozhsky, V. [Institute for nuclear research (Ukraine)

    2014-07-01

    The study of the migration of {sup 90}Sr, {sup 137}Cs, {sup 241}Am and Pu isotopes in soil near Chernobyl nuclear power plant area, as well as the Chernigov region, Ukraine is described. Experiments were conducted using a semiconductor spectrometry and radiochemical separation of isotopes needed. The experimental data obtained were processed using a mathematical model that takes into account in convective component (fit parameter V-- linear velocity of radionuclide movement dependent upon soil moisture) and diffusive one (fit parameter D- diffusion coefficient) migration of isotopes. The parameter values in V and D of migration, in turn, allow us to estimate halftime of decontamination top five-centimeter layer of soil. The results obtained in this paper halftime of decontamination for the various isotopes and their comparison with those obtained by us and by other authors in the past 10-20 years, confirms the trend previously noticed by a significant speeding migration Radiostrontium compared with Radiocesium. It is shown that for all the types studied soils in the late phase of Chernobyl accident halftime of decontamination of the top 5 - cm soil layer for radiostrontium, and for radioactive cesium in the order of magnitude or more greater than the period of the physical half-life of the radionuclide that is, matching in the late phase of the accident change the exposure dose of radiation is mainly determined by the physical decay of the radionuclide. According to the estimated periods decontamination upper soil horizons of different migration mobility of radionuclides in soils exclusion zone reduced in number: {sup 90}Sr> {sup 137}Cs> {sup 241}Am ≥ {sup 238-240}Pu, migration mobility of isotopes of transuranic elements is very low. Document available in abstract form only. (authors)

  15. A study of uranium and thorium migration at the Koongarra uranium deposit with application to actinide transport from nuclear waste repositories

    International Nuclear Information System (INIS)

    Payne, T.E.

    1991-01-01

    One way to gain confidence in modelling possible radionuclide releases is to study natural systems which are similar to components of the multibarrier waste repository. Several such analogues are currently under study and these provide useful data about radionuclide behaviour in the natural environment. One such system is the Koongarra uranium deposit in the Northern Territory. In this dissertation, the migration of actinides, primarily uranium and thorium, has been studied as an analogue for the behaviour of transuranics in the far-field of a waste repository. The major findings of this study are: 1. the main process retarding uranium migration in the dispersion fan at Koongarra is sorption, which suppresses dissolved uranium concentrations well below solubility limits, with ferrihydrite being a major sorbing phase; 2. thorium is extremely immobile, with very low dissolved concentrations and corresponding high distribution ratios for 230 Th. Overall, it is estimated that colloids are relatively unimportant in Koongarra groundwater. Uranium migrates mostly as dissolved species, whereas thorium and actinium are mostly adsorbed to larger, relatively immobile particles and the stationary phase. However, of the small amount of 230 Th that passes through a 1μm filter, a significant proportion is associated with colloidal particles. Actinium appears to be slightly more mobile than thorium and is associated with colloids to a greater extent, although generally present in low concentrations. These results support the possibility of colloidal transport of trivalent and tetravalent actinides in the vicinity of a nuclear waste repository. 112 refs., 23 tabs., 32 figs

  16. The Migration Behaviour of Cesium-137 on the Soils of Muria Peninsula as the Area of Nuclear Power Plant Site's Candidate

    International Nuclear Information System (INIS)

    Ngasifudin; Herry Purnomo; Endro Kismolo

    2002-01-01

    The research on kinetic and migration of Caesium-137 on the soils of Muria Peninsula as the area of Nuclear Power Plant site's candidate have been done. The migration process of cesium in soil is influenced by physical and chemical properties of soil and environment in which the sorption process is occurred. These physics and chemical properties data and radionuclide retardation factor in such area are needed on the study of mathematic models of radionuclide migration. The experiment results are, porosity : 0.479 - 0.566; the water flowrate average : 5.91 x 10 -4 - 4.48 X 10 -2 cm/second; the longitudinal dispersivity : 0.030 - 0.241 cm; the coefficient of longitudinal dispersivity : 4.96 x 10 -5 - 7.69 X 10 -3 cm 2 /second and retardation factor : 2.30 - 3.39. The result of minerals content of soils for the depth 0-30 cm in average is in the range of : for sand 53.17%, for clay 10.48%, for dust 36.37% and moisture 2.58%. (author)

  17. A REVIEW OF HUMAN-SYSTEM INTERFACE DESIGN ISSUES OBSERVED DURING ANALOG-TO-DIGITAL AND DIGITAL-TO-DIGITAL MIGRATIONS IN U.S. NUCLEAR POWER PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Kovesdi, C.; Joe, J.

    2017-05-01

    The United States (U.S.) Department of Energy (DOE) Light Water Reactor Sustainability (LWRS) program is developing a scientific basis through targeted research and development (R&D) to support the U.S. nuclear power plant (NPP) fleet in extending their existing licensing period and ensuring their long-term reliability, productivity, safety, and security. Over the last several years, human factors engineering (HFE) professionals at the Idaho National Laboratory (INL) have supported the LWRS Advanced Instrumentation, Information, and Control (II&C) System Technologies pathway across several U.S. commercial NPPs in analog-to-digital migrations (i.e., turbine control systems) and digital-to-digital migrations (i.e., Safety Parameter Display System). These efforts have included in-depth human factors evaluation of proposed human-system interface (HSI) design concepts against established U.S. Nuclear Regulatory Commission (NRC) design guidelines from NUREG-0700, Rev 2 to inform subsequent HSI design prior to transitioning into Verification and Validation. This paper discusses some of the overarching design issues observed from these past HFE evaluations. In addition, this work presents some observed challenges such as common tradeoffs utilities are likely to face when introducing new HSI technologies into NPP hybrid control rooms. The primary purpose of this work is to distill these observed design issues into general HSI design guidance that industry can use in early stages of HSI design.

  18. Vertical Migration of Radionuclides in Soils on the Chernobyl Nuclear Power Plant (ChNPP) Exclusion Zone (1987-2007)

    Science.gov (United States)

    Jannik, G. T.; Ivanov, Y. A.; Kashparov, V. A.; Levchuk, S. E.; Bondarkov, M. D.; Maksymenko, A. M.; Farfan, E. B.; Marra, J. C.

    2009-12-01

    In 1986-1987, a set of experimental sites for studies of vertical migration of radionuclides released from the ChNPP was established in the ChNPP Exclusion Zone for various fallout plumes. The sites were selected considering local terrain and geo-chemical conditions, as well as physical and chemical characteristics of the fallout. The experimental sites included grasslands, and pre-Chernobyl cultivated meadows and croplands. Vertical migration of radionuclides in the ChNPP Exclusion Zone grasslands was evaluated. Parameters of 137Cs, 90Sr, and 239,240Pu transfer were calculated and the periods during which these radionuclides reach their ecological half-life in the upper 5 cm soil layer were estimated. Migration capabilities of these radionuclides in the grassland soils tend to decrease as follows: 90Sr >137Cs ≥ 239,240Pu. A significant retardation of the 137Cs vertical migration was shown in the grasslands long after the Chernobyl accident. During the 21st year after the fallout, average Tecol values for 137Cs (the period of time it takes in the environment for 137Cs to reach half the value of its original concentration in the upper 5 cm soil layer, regardless of physical decay) are as follows: 180 - 320 years for grassland containing automorphous mineral soils of a light granulometric composition; and 90 - 100 years for grassland containing hydromorphous organogenic soils. These values are significantly higher than those estimated for the period of 6-9 years after the fallout: 60 - 150 years and 11 - 20 years, respectively. The absolute 137Cs Tecol values are by factors of 3-7 higher than 137Cs radiological decay values long after the accident. Changes in the exposure dose resulting from the soil deposited 137Cs only depend on its radiological decay. This factor should necessarily be considered for development of predictive assessments, including dose exposures for the hypothetical population in case of their re-evacuation to the exclusion areas. The obtained

  19. A Dual-Continuum Model for Brine Migration in Salt Associated with Heat-Generating Nuclear Waste: Fully Coupled Thermal-Hydro-Mechanical Analysis

    Science.gov (United States)

    Hu, M.; Rutqvist, J.

    2017-12-01

    The disposal of heat-generating nuclear waste in salt host rock establishes a thermal gradient around the waste package that may cause brine inclusions in the salt grains to migrate toward the waste package. In this study, a dual-continuum model is developed to analyze such a phenomenon. This model is based on the Finite Volume Method (FVM), and it is fully thermal-hydro-mechanical (THM) coupled. For fluid flow, the dual-continuum model considers flow in the interconnected pore space and also in the salt grains. The mass balance of salt and water in these two continua is separately established, and their coupling is represented by flux associated with brine migration. Together with energy balance, such a system produces a coupled TH model with strongly nonlinear features. For mechanical analysis, a new formulation is developed based on the Voronoi tessellated mesh. By relating each cell to several connected triangles, first-order approximation is constructed. The coupling between thermal and mechanical fields is only considered in terms of thermal expansion. And the coupling between the hydraulic and mechanical fields in terms of pore-volume effects is consistent with Biot's theory. Therefore, a fully coupled THM model is developed. Several demonstration examples are provided to verify the model. Last the new model is applied to analyze coupled THM behavior and the results are compared with experimental data.

  20. The Oklo natural nuclear reactors: neutron parameters, age and duration of the reactions, uranium and fission products migrations

    International Nuclear Information System (INIS)

    Ruffenach, J.-C.

    1979-09-01

    Mass spectrometry and isotopic dilution technique are used in order to carry out, on various samples from the fossil nuclear reactors at Oklo, Gabon, isotopic and chemical analyses of some particular elements involved in the nuclear reactions: uranium, lead, bismuth, thorium, rare gases (krypton, xenon), rare earths (neodymium, samarium, europium, gadolinium, dysprosium), ruthenium and palladium. Interpretations of these analyses lead to the determination of many neutron parameters such as the neutron fluence received by the samples, the spectrum index, the conversion coefficient, and also the percentages of fissions due to uranium-238 and plutonium-239 and the total number of fissions relative to uranium. All these results make it possible to determine the age of the nuclear reactions by measuring the amounts of fission rare earths formed, i.e. 1.97 billion years. This study brings some informations to the general problem of radioactive wastes storage in deep geological formations, the storage of uranium, plutonium and many fission products having been carried out naturally, and for about two billion years [fr

  1. Deuterium migration in nuclear graphite: consequences for the behavior of tritium in Gas Cooled Reactors and for the decontamination of irradiated graphite waste

    International Nuclear Information System (INIS)

    Le-Guillou, Mael

    2014-01-01

    In France, 23 000 t of irradiated graphite that will be generated by the decommissioning of the first generation Uranium Naturel-Graphite-Gaz (UNGG) nuclear reactors are waiting for a long term management solution. This work focuses on the behavior of tritium, which is one of the main contributors to the radiological inventory of graphite waste after reactor shutdown. In order to anticipate tritium release during dismantling or waste management, it is mandatory to collect data on its migration, location and inventory. Our study is based on the simulation of tritium by implantation of approximately 3 at. % of deuterium up to around 3 μm in a virgin nuclear graphite. This material was then annealed up to 300 h and 1300 C in inert atmosphere, UNGG coolant gas and humid gas, aiming to reproduce thermal conditions close to those encountered in reactor and during waste management operations. The deuterium profiles and spatial distribution were analyzed using the nuclear reaction 2 H( 3 He,p) 4 He. The main results evidence a thermal release of implanted deuterium occurring essentially through three regimes controlled by the detrapping of atomic deuterium located in superficial or interstitial sites. The extrapolation of our data to tritium suggests that its purely thermal release during reactor operations may have been lower than 30 % and would be located close to the graphite free surfaces. Consequently, most of the tritium inventory after reactor shutdown could be trapped deeply within the irradiated graphite structure. Decontamination of graphite waste should then require temperatures higher than 1300 C, and would be more efficient in dry inert gas than in humid gas. (author)

  2. Numerical modeling of gas migration at a proposed repository for low and intermediate level nuclear wastes at Oberbauenstock, Switzerland

    International Nuclear Information System (INIS)

    Pruess, K.

    1990-03-01

    Hydrologic impacts of corrosive gas release from a hypothetical L/ILW nuclear waste repository at Oberbauenstock are explored by means of numerical simulation. A schematic two dimensional vertical section through the mountain is modeled with the simulator TOUGH, which describes two-phase flow of water and gas in porous and fractured media. Two reference cases are considered which represent the formations as a porous and as a fractured-porous (dual permeability) medium, respectively. Both cases predict similar and rather modest pressure increases, from ambient 10 bars to near 25 bars at the repository level. These results are to be considered preliminary because important parameters affecting two-phase flow, such as relative permeabilities of a fractured medium, are not well known at present. 24 refs., 15 figs., 5 tabs

  3. Three-Dimensional Modelling of a KBS-3 Canister for Spent Nuclear Fuel - some migration studies - phase II

    International Nuclear Information System (INIS)

    Pereira, Antonio

    2007-08-01

    The resistance approach is nowadays very common in compartment modelling of radionuclide mass transport. In this work we examine with the help of a finite element code a particular application of the resistance approach method as used in modelling the near field of a KBS-3V repository. The motivation behind this work is that, although conceptually simple, the resistance approach to mass transfer, using many compartments linked together by resistances, rises two important issues related to the review process: transparency and quality assurance. Transforming the real geometry of the repository system in a number of 'equivalent compartments' makes for instance the input data used by the software difficult to grasp and the codes hard to read. With our three-dimensional finite element model we simulate the release of radionuclides from a copper canister perforated by a small pinhole through which the radionuclides escape from the canister gap and migrate in the bentonite by means of diffusion until they reach the fractured rock. Release rates are calculated for two radionuclides and the breakthrough curves are compared with SKB results. This direct approach to study the impact of the resistance methodology shows that the results obtained by the 3D-model are relatively close to the predictions of the compartment models of SKB. However, our model has a pinhole with constant cross section, introducing an important conceptual difference between the two models. In the SKB-model that cross section increases suddenly at 20 000 years. This implies that the boundary conditions of the two models are different, which impacts on the breakthrough curves of radionuclides which are not short-lived, even if we only model up to 20 000 years. Therefore the agreement between the two models is better for short-lived radionuclides. It is also shown in this report that the use of a commercial package of finite elements allows build a coupled flow-and mass transport model in 3D, using

  4. A study on migration of contaminants and effect on the groundwater system at the Gemencheh domestic waste disposal site, Negeri Sembilan using integrated nuclear, geophysical and hydrogeochemical methods

    International Nuclear Information System (INIS)

    Mohd Tadza Abdul Rahman

    2001-01-01

    The domestic waste disposal site at Gemencheh, Negeri Sembilan has been in operation since 1981. Integration of three methods namely nuclear, geophysical and hydrogeochemical were used to study the migration and effects of contaminants on the groundwater system at this particular site. Nuclear method was used to determine groundwater system flow velocity that delineates the migration pattern of contaminant species in the groundwater system at the study area. The groundwater flow velocity is found to be heterogeneous and depend on hydraulic conductivity caused by soil permeability except in the low-lying downstream area where the flow velocity is found to be low and constant at 2.0 x 10 -6 ms -1 . However, the flow velocity increases to as high as 17.8 x 10 -5 ms -1 during rainy season due to the influence of weather on hydraulic gradient. Weather condition also influences the flow direction, whereby during draught season, the groundwater flow direction at the middle of the study site moves from an area of high topography to the northeast and southeast of low topography areas. On the other hand, at the downstream the groundwater flows partially towards northeast and southeast whereas flow direction at the upstream is towards the east. A similar pattern was observed during rainy season in both upstream and downstream of the study site but at the middle, the flow is basically towards south-east with a side flow to the north-east and east direction. Geophysical method comprising geo electrical-imaging and electromagnetic transient techniques was used to determine the extent, depth and distribution of contamination in the groundwater system. This method shows that the most seriously contaminated areas at the middle and the downstream regions of the study site within the shallow depth of 3-6 metres. The distribution of the contaminants in groundwater is not widespread but confined within the study site only. Finally, hydrogeochemical method was used to determine the

  5. The solubility of nickel and its migration through the cementitious backfill of a geological disposal facility for nuclear waste.

    Science.gov (United States)

    Felipe-Sotelo, M; Hinchliff, J; Field, L P; Milodowski, A E; Holt, J D; Taylor, S E; Read, D

    2016-08-15

    This work describes the solubility of nickel under the alkaline conditions anticipated in the near field of a cementitious repository for intermediate level nuclear waste. The measured solubility of Ni in 95%-saturated Ca(OH)2 solution is similar to values obtained in water equilibrated with a bespoke cementitious backfill material, on the order of 5×10(-7)M. Solubility in 0.02M NaOH is one order of magnitude lower. For all solutions, the solubility limiting phase is Ni(OH)2; powder X-ray diffraction and scanning transmission electron microscopy indicate that differences in crystallinity are the likely cause of the lower solubility observed in NaOH. The presence of cellulose degradation products causes an increase in the solubility of Ni by approximately one order of magnitude. The organic compounds significantly increase the rate of Ni transport under advective conditions and show measurable diffusive transport through intact monoliths of the cementitious backfill material. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Determination and maintenance of DE minimis risk for migration of residual tritium (3H) from the 1969 Project Rulison nuclear test to nearby hydraulically fractured natural gas wells.

    Science.gov (United States)

    Daniels, Jeffrey I; Chapman, Jenny B

    2013-05-01

    The Project Rulison underground nuclear test was a proof-of-concept experiment that was conducted under the Plowshare Program in 1969 in the Williams Fork Formation of the Piceance Basin in west-central Colorado. Today, commercial production of natural gas is possible from low permeability, natural gas bearing formations like that of the Williams Fork Formation using modern hydraulic fracturing techniques. With natural gas exploration and production active in the Project Rulison area, this human health risk assessment was performed in order to add a human health perspective for site stewardship. Tritium (H) is the radionuclide of concern with respect to potential induced migration from the test cavity leading to subsequent exposure during gas-flaring activities. This analysis assumes gas flaring would occur for up to 30 d and produce atmospheric H activity concentrations either as low as 2.2 × 10 Bq m (6 × 10 pCi m) from the minimum detectable activity concentration in produced water or as high as 20.7 Bq m (560 pCi m), which equals the highest atmospheric measurement reported during gas-flaring operations conducted at the time of Project Rulison. The lifetime morbidity (fatal and nonfatal) cancer risks calculated for adults (residents and workers) and children (residents) from inhalation and dermal exposures to such activity concentrations are all below 1 × 10 and considered de minimis. The implications for monitoring production water for conforming health-protective, risk-based action levels also are examined.

  7. 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.)

  8. Deuterium migration in nuclear graphite: Consequences for the behavior of tritium in CO{sub 2}-cooled reactors and for the decontamination of irradiated graphite waste

    Energy Technology Data Exchange (ETDEWEB)

    Le Guillou, M. [Institut de Physique Nucléaire de Lyon, CNRS/IN2P3 UMR 5822, Université Claude Bernard Lyon 1, Université de Lyon – 4, rue Enrico Fermi, F-69622 Villeurbanne cedex (France); Agence nationale pour la gestion des déchets radioactifs, DRD/CM – 1-7, rue Jean Monnet, Parc de la Croix-Blanche, F-92298 Châtenay-Malabry cedex (France); Toulhoat, N., E-mail: nelly.toulhoat@univ-lyon1.fr [Institut de Physique Nucléaire de Lyon, CNRS/IN2P3 UMR 5822, Université Claude Bernard Lyon 1, Université de Lyon – 4, rue Enrico Fermi, F-69622 Villeurbanne cedex (France); CEA/DEN – Centre de Saclay, F-91191 Gif-sur-Yvette cedex (France); Pipon, Y. [Institut de Physique Nucléaire de Lyon, CNRS/IN2P3 UMR 5822, Université Claude Bernard Lyon 1, Université de Lyon – 4, rue Enrico Fermi, F-69622 Villeurbanne cedex (France); Institut Universitaire Technologique, Université Claude Bernard Lyon 1, Université de Lyon – 43, boulevard du 11 novembre 1918, F-69622 Villeurbanne cedex (France); Moncoffre, N. [Institut de Physique Nucléaire de Lyon, CNRS/IN2P3 UMR 5822, Université Claude Bernard Lyon 1, Université de Lyon – 4, rue Enrico Fermi, F-69622 Villeurbanne cedex (France); Khodja, H. [Laboratoire d’Etude des Eléments Légers, CEA/DSM/IRAMIS/NIMBE, UMR 3299 SIS2M – Centre de Saclay, F-91191 Gif-sur-Yvette cedex (France)

    2015-06-15

    In this paper, we aim at understanding tritium behavior in the graphite moderator of French CO{sub 2}-cooled nuclear fission reactors (called UNGG for “Uranium Naturel-Graphite-Gaz”) to get information on its distribution and inventory in the irradiated graphite waste after their dismantling. These findings should be useful both to improve waste treatment processes and to foresee tritium behavior during reactor decommissioning and waste disposal operations. The purpose of the present work is to elucidate the effects of temperature on the behavior of tritium during reactor operation. Furthermore, it aims at exploring options of thermal decontamination. For both purposes, annealing experiments were carried out in inert atmosphere as well as in thermal conditions as close as possible to those encountered in UNGG reactors and in view of a potential decontamination in humid gas. D{sup +} ions were implanted into virgin nuclear graphite in order to simulate tritium displaced from its original structural site through recoil during reactor operation. The effect of thermal treatments on the mobility of the implanted deuterium was then investigated at temperatures ranging from 200 to 1200 °C, in inert atmosphere (vacuum or argon), in a gas simulating the UNGG coolant gas (mainly CO{sub 2}) or in humid nitrogen. Deuterium was analyzed by Nuclear Reaction Analysis (NRA) both at millimetric and micrometric scales. We have identified three main stages for the deuterium release. The first one corresponds to deuterium permeation through graphite open pores. The second and third ones are controlled by the progressive detrapping of deuterium located at different trapping sites and its successive migration through the crystallites and along crystallites and coke grains edges. Extrapolating the thermal behavior of deuterium to tritium, the results show that the release becomes significant above the maximum UNGG reactor temperature of 500 °C and should be lower than 30% of the

  9. Humic substances in performance assessment of nuclear waste disposal: Actinide and iodine migration in the far-field. First technical progress report

    International Nuclear Information System (INIS)

    Buckau, G.

    2003-04-01

    The present project is one in a series of research activities supported by the European Commission on the role of humic substances for the long-term safety of nuclear waste disposal. These activities started in the mid eighties within the MIRAGE project (MIgration of RAdionuclides in the GEosphere) with the most recent project being ''Effects of humic substances on the migration of radionuclides: Complexation and transport of actinides (HUMICS)'' (FI4W-CT96-0028). The HUMICS project was conducted within the fourths framework of the European Commissions research program. It started January 1997 and had a duration of three years. The results of the HUMICS project can be found in three open technical progress reports and a final report [1-4]. In analogy with the HUMICS project, the present project makes use of annual technical progress reports where individual results are published as papers in the form of annexes. By this approach, results rapidly become available to interested parties in a compact form before their publication in various scientific journals and conference proceedings. Furthermore, some of the more preliminary and/or detailed results are not likely to appear in scientific journals and proceedings. The present project is conducted within the fifths framework of the European Commissions research program. It started November 2001 and has a duration of three years. The present report covers the first project year, i.e. November 2001 to September 2002. The project is divided into eight different work packages. These are (i) ''Critical assessment of experimental methods'', (ii) ''Generation and characterization of humic substances'', (iii) ''Radionuclide humate interaction data by designed system investigations'', (iv) ''Characterization of radionuclide humate complexes'', (v) ''Natural chemical analogue studies'', (vi) ''Radionuclide transport experiments'', (vii) ''Model development'', and (viii) ''Performance assessment''. Division of work into

  10. Long-term Performance of PVC and CSPE Cables used in Nuclear Power Plants: the Effect of Degradation and Plasticizer migration

    International Nuclear Information System (INIS)

    Ekelund, Maria

    2009-10-01

    Enormous amounts of low voltage cables installed in a Swedish nuclear power plant are reaching their expected lifetimes. Since the cables are crucial to operational safety, it is of great importance that the actual condition of the installed cables is determined. In this study, cables based on poly(vinyl chloride) plasticized with di(2-ethylhexyl)phthalate (DEHP) were examined with respect to the degradation mechanisms responsible for the ageing of the insulation. This was achieved by studying samples that underwent accelerated ageing by different analytical methods, such as indenter modulus measurements, tensile testing, infrared spectroscopy, differential scanning calorimetry and liquid chromatography, to assess the condition of the cables. The results were unambiguous; the main deterioration mechanism differed for the jacket and the core insulation. The immediate increase in stiffness of the jacket insulation suggests that loss of plasticizer was the dominant cause for degradation. The core insulation on the other hand showed much smaller changes in the mechanical properties due to thermal ageing with an activation energy of the change in the indenter modulus matching that of the dehydrochlorination process. The electrical functionality during high-energy line break accident was correlated to the mechanical properties of the cable and this correlation was used to establish a lifetime criterion. The mechanical data showed Arrhenius temperature dependence with activation energies of 80 kJ/mol and 100 kJ/mol for the jacketing and 130 kJ/mol for the core insulation. These activation energies were used to extrapolate the lifetimes to service temperatures (20 deg C to 50 deg C). Plasticizer migration was determined as the lifetime controlling mechanism at the service temperatures. Experimental data, obtained by extraction of DEHP followed by liquid chromatography, were analysed by numerical methods to gain a better understanding of the migration. The analysis showed

  11. Long-term Performance of PVC and CSPE Cables used in Nuclear Power Plants: the Effect of Degradation and Plasticizer migration

    Energy Technology Data Exchange (ETDEWEB)

    Ekelund, Maria

    2009-10-15

    Enormous amounts of low voltage cables installed in a Swedish nuclear power plant are reaching their expected lifetimes. Since the cables are crucial to operational safety, it is of great importance that the actual condition of the installed cables is determined. In this study, cables based on poly(vinyl chloride) plasticized with di(2-ethylhexyl)phthalate (DEHP) were examined with respect to the degradation mechanisms responsible for the ageing of the insulation. This was achieved by studying samples that underwent accelerated ageing by different analytical methods, such as indenter modulus measurements, tensile testing, infrared spectroscopy, differential scanning calorimetry and liquid chromatography, to assess the condition of the cables. The results were unambiguous; the main deterioration mechanism differed for the jacket and the core insulation. The immediate increase in stiffness of the jacket insulation suggests that loss of plasticizer was the dominant cause for degradation. The core insulation on the other hand showed much smaller changes in the mechanical properties due to thermal ageing with an activation energy of the change in the indenter modulus matching that of the dehydrochlorination process. The electrical functionality during high-energy line break accident was correlated to the mechanical properties of the cable and this correlation was used to establish a lifetime criterion. The mechanical data showed Arrhenius temperature dependence with activation energies of 80 kJ/mol and 100 kJ/mol for the jacketing and 130 kJ/mol for the core insulation. These activation energies were used to extrapolate the lifetimes to service temperatures (20 deg C to 50 deg C). Plasticizer migration was determined as the lifetime controlling mechanism at the service temperatures. Experimental data, obtained by extraction of DEHP followed by liquid chromatography, were analysed by numerical methods to gain a better understanding of the migration. The analysis showed

  12. Migrating Worker

    DEFF Research Database (Denmark)

    Hansen, Hans

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

  13. Dateline Migration.

    Science.gov (United States)

    Tomasi, Lydio E., Ed.

    1995-01-01

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

  14. Directional Migration in Esophageal Squamous Cell Carcinoma (ESCC) is Epigenetically Regulated by SET Nuclear Oncogene, a Member of the Inhibitor of Histone Acetyltransferase Complex

    OpenAIRE

    Xiang Yuan; Xinshuai Wang; Bianli Gu; Yingjian Ma; Yiwen Liu; Man Sun; Jinyu Kong; Wei Sun; Huizhi Wang; Fuyou Zhou; Shegan Gao

    2017-01-01

    Directional cell migration is of fundamental importance to a variety of biological events, including metastasis of malignant cells. Herein, we specifically investigated SET oncoprotein, a subunit of the recently identified inhibitor of acetyltransferases (INHAT) complex and identified its role in the establishment of front–rear cell polarity and directional migration in Esophageal Squamous Cell Carcinoma (ESCC). We further define the molecular circuits that govern these processes by showing t...

  15. 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...

  16. Fluid migration studies in salt

    International Nuclear Information System (INIS)

    Shefelbine, H.C.; Raines, G.E.

    1980-01-01

    This discussion will be limited to the migration of water trapped in the rock salt under the influence of the heat field produced by nuclear waste. This is of concern because hypotheticl scenarios have been advanced in which this fluid movement allows radionuclides to escape to the biosphere. While portions of these scenarios are supported by observation, none of the complete scenarios has been demonstrated. The objectives of the present fluid migration studies are two-fold: 1. determine the character of the trapped fluid in terms of quantity, habitat and chemical constituents; and 2. define the mechanisms that cause the fluid to migrate toward heat sources. Based on the observations to date, fluid migration will not have a major impact on repository integrity. However, the above objectives will be pursued until the impacts, if any, can be quantified

  17. Oklo natural reactor. Study of uranium and rare earths migration on a core drilled through a reaction zone. Application to determination of the date of the nuclear reaction by measurement of fission products

    International Nuclear Information System (INIS)

    Ruffenach, J.C.

    1977-01-01

    Isotopic and chemical analysis of uranium and five rare earths: neodymium, samarium, europium, gadolinium and dysprosium were effected on fourteen samples taken in the same core drilled through a reaction zone of the Oklo uranium deposit. This study points out the general stability of uranium and fission rare earths; spatial distributions of these elements are quite analogous. Migrations have affected about 5% only of fission neodymium in the core of the reaction zone; corresponding values for samarium and gadolinium are slightly higher. These migration phenomena have carried rare earths to no more than 80 cm out of the core. By study of the europium it is shown that nuclear reactions have stayed in the ground since the time of reactions. On the other hand it is shown by analysis of the dysprosium that rare earths have not undergone an important movement. This study allow also the datation of nuclear reactions from the measurement of the quantity of fission neodymium produced. A value of 1.98x10 9 years is obtained slightly higher than the value obtained by geochronology [fr

  18. Rural migration in southern Nevada

    International Nuclear Information System (INIS)

    Mosser, D.; Soden, D.L.

    1993-01-01

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

  19. Clonorchis sinensis excretory-secretory products regulate migration and invasion in cholangiocarcinoma cells via extracellular signal-regulated kinase 1/2/nuclear factor-κB-dependent matrix metalloproteinase-9 expression.

    Science.gov (United States)

    Pak, Jhang Ho; Shin, Jimin; Song, In-Sung; Shim, Sungbo; Jang, Sung-Wuk

    2017-01-01

    Matrix metalloproteinase-9 plays an important role in the invasion and metastasis of various types of cancer cells. We have previously reported that excretory-secretory products from Clonorchis sinensis increases matrix metalloproteinase-9 expression. However, the regulatory mechanisms through which matrix metalloproteinase-9 expression affects cholangiocarcinoma development remain unclear. In the current study, we examined the potential role of excretory-secretory products in regulating the migration and invasion of various cholangiocarcinoma cell lines. We demonstrated that excretory-secretory products significantly induced matrix metalloproteinase-9 expression and activity in a concentration-dependent manner. Reporter gene and chromatin immunoprecipitation assays showed that excretory-secretory products induced matrix metalloproteinase-9 expression by enhancing the activity of nuclear factor-kappa B. Moreover, excretory-secretory products induced the degradation and phosphorylation of IκBα and stimulated nuclear factor-kappa B p65 nuclear translocation, which was regulated by extracellular signal-regulated kinase 1/2. Taken together, our findings indicated that the excretory-secretory product-dependent enhancement of matrix metalloproteinase-9 activity and subsequent induction of IκBα and nuclear factor-kappa B activities may contribute to the progression of cholangiocarcinoma. Copyright © 2016 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.

  20. Concentration Sensing by the Moving Nucleus in Cell Fate Determination: A Computational Analysis.

    Directory of Open Access Journals (Sweden)

    Varun Aggarwal

    Full Text Available During development of the vertebrate neuroepithelium, the nucleus in neural progenitor cells (NPCs moves from the apex toward the base and returns to the apex (called interkinetic nuclear migration at which point the cell divides. The fate of the resulting daughter cells is thought to depend on the sampling by the moving nucleus of a spatial concentration profile of the cytoplasmic Notch intracellular domain (NICD. However, the nucleus executes complex stochastic motions including random waiting and back and forth motions, which can expose the nucleus to randomly varying levels of cytoplasmic NICD. How nuclear position can determine daughter cell fate despite the stochastic nature of nuclear migration is not clear. Here we derived a mathematical model for reaction, diffusion, and nuclear accumulation of NICD in NPCs during interkinetic nuclear migration (INM. Using experimentally measured trajectory-dependent probabilities of nuclear turning, nuclear waiting times and average nuclear speeds in NPCs in the developing zebrafish retina, we performed stochastic simulations to compute the nuclear trajectory-dependent probabilities of NPC differentiation. Comparison with experimentally measured nuclear NICD concentrations and trajectory-dependent probabilities of differentiation allowed estimation of the NICD cytoplasmic gradient. Spatially polarized production of NICD, rapid NICD cytoplasmic consumption and the time-averaging effect of nuclear import/export kinetics are sufficient to explain the experimentally observed differentiation probabilities. Our computational studies lend quantitative support to the feasibility of the nuclear concentration-sensing mechanism for NPC fate determination in zebrafish retina.

  1. Nuclear

    International Nuclear Information System (INIS)

    2014-01-01

    This document proposes a presentation and discussion of the main notions, issues, principles, or characteristics related to nuclear energy: radioactivity (presence in the environment, explanation, measurement, periods and activities, low doses, applications), fuel cycle (front end, mining and ore concentration, refining and conversion, fuel fabrication, in the reactor, back end with reprocessing and recycling, transport), the future of the thorium-based fuel cycle (motivations, benefits and drawbacks), nuclear reactors (principles of fission reactors, reactor types, PWR reactors, BWR, heavy-water reactor, high temperature reactor of HTR, future reactors), nuclear wastes (classification, packaging and storage, legal aspects, vitrification, choice of a deep storage option, quantities and costs, foreign practices), radioactive releases of nuclear installations (main released radio-elements, radioactive releases by nuclear reactors and by La Hague plant, gaseous and liquid effluents, impact of releases, regulation), the OSPAR Convention, management and safety of nuclear activities (from control to quality insurance, to quality management and to sustainable development), national safety bodies (mission, means, organisation and activities of ASN, IRSN, HCTISN), international bodies, nuclear and medicine (applications of radioactivity, medical imagery, radiotherapy, doses in nuclear medicine, implementation, the accident in Epinal), nuclear and R and D (past R and D programmes and expenses, main actors in France and present funding, main R and D axis, international cooperation)

  2. 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 ...

  3. Problems of radio-nuclear risks and radioecological safety, caused by migration and contamination of seas and Arctic Ocean waters in Northern regions

    International Nuclear Information System (INIS)

    Koupri, K.

    1997-01-01

    Northern Russian radio-ecological and nuclear risks are connected with several objective factors: disposal, exploitation, supplying of the cycle of atomic military and ice-breaking fleets; disposal of enterprises and bases for maintenance of ships with nuclear-power installations (NPI) in Murmansk and Archangel regions; place the State Atomic Shipbuilding Center (RSASBC) enterprises in Archangel and partly in Murmansk regions; exploitation of the Kola Atomic Station (APS); functioning of the Novaya Zemlya archipelago nuclear range; functioning Russian Plesetsk cosmo-drome. Technical proposals and projects for radio-ecology in the North are outlined. (R.P.)

  4. Directional Migration in Esophageal Squamous Cell Carcinoma (ESCC is Epigenetically Regulated by SET Nuclear Oncogene, a Member of the Inhibitor of Histone Acetyltransferase Complex

    Directory of Open Access Journals (Sweden)

    Xiang Yuan

    2017-11-01

    Full Text Available Directional cell migration is of fundamental importance to a variety of biological events, including metastasis of malignant cells. Herein, we specifically investigated SET oncoprotein, a subunit of the recently identified inhibitor of acetyltransferases (INHAT complex and identified its role in the establishment of front–rear cell polarity and directional migration in Esophageal Squamous Cell Carcinoma (ESCC. We further define the molecular circuits that govern these processes by showing that SET modulated DOCK7/RAC1 and cofilin signaling events. Moreover, a detailed analysis of the spatial distribution of RAC1 and cofilin allowed us to decipher the synergistical contributions of the two in coordinating the advancing dynamics by measuring architectures, polarities, and cytoskeletal organizations of the lamellipodia leading edges. In further investigations in vivo, we identified their unique role at multiple levels of the invasive cascade for SET cell and indicate the necessity for their functional balance to enable efficient invasion as well. Additionally, SET epigenetically repressed miR-30c expression by deacetylating histones H2B and H4 on its promoter, which was functionally important for the biological effects of SET in our cell-context. Finally, we corroborated our findings in vivo by evaluating the clinical relevance of SET signaling in the metastatic burden in mice and a large series of patients with ESCC at diagnosis, observing it's significance in predicting metastasis formation. Our findings uncovered a novel signaling network initiated by SET that epigenetically modulated ESCC properties and suggest that targeting the regulatory axis might be a promising strategy to inhibit migration and metastasis.

  5. Rural migration in Nevada: Lincoln County

    International Nuclear Information System (INIS)

    Soden, D.L.; Carns, D.E.; Mosser, D.; Conary, J.S.; Ansell, J.P.

    1993-01-01

    The principal objective of this project was to develop insight into the scope of migration of working age Nevadans out of their county of birth; including the collection of data on their skill levels, desire to out or in-migrate, interactions between families of migratory persons, and the impact that the proposed high-level nuclear waste repository at Yucca mountain might have on their individual, and collective, decisions to migrate and return. The initial phase of this project reported here was conducted in 1992 and 1993 in Lincoln County, Nevada, one of the counties designated as ''affected'' by the proposed repository program. The findings suggest that a serious out-migration problem in Lincoln County, and that the Yucca mountain project will likely affect decisions relating to migration patterns in the future

  6. Surveying for migration pathways in the granitic rock using nuclear track detectors, autoradiography and digital image analysis as an aid to construct the basis for heterogeneous diffusion modeling

    International Nuclear Information System (INIS)

    Kemppainen, M.; Oila, E.; Siitari-Kauppi, M.

    2001-01-01

    Radioelement migration within a rock matrix under natural long-term conditions is a complex process controlled by various parameters. Pure physical parameters such as porosity, hydraulic conductivity and diffusivity are usually sufficient to describe transport in well-defined laboratory systems. In natural rock matrices transport is influenced by physical pore properties such as pore size distribution, connectivity, tortuosity, constrictivity and petrological and chemical nature and charge on the fluid-rock interface. The overall characterization of heterogeneous rock structures is needed for the accurate heterogeneous diffusion modeling. Here we describe a method for the detection of α-particles from uranium in cm-scale rock samples based on the analysis of the tracks formed in organic polymer, CR-39. On the other hand the uranium tracks were compared with the migration pathways and porosity distribution produced with the 14 C-polymethylmethacrylate impregnation method ( 14 C-PMMA). For analyzing mineral specific uranium occurrence and porosities the staining methods were used to produce the mineral map of the rock sample. Digital image analysis techniques were applied to the different cm-scale pictures of rock samples. Scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDS) were performed in order both to study the pore apertures of grain boundaries and fissures in greater detail and to detect the uranium phases. The high uranium content was found to be congruent with the porous mineral phases; altered plagioclase and biotite grains, and the intra- and intergranular fissures detected with the 14 C-PMMA technique. Plenty of microfractures transsecting potassium feldspar and quartz grains were filled with calcite together with precipitated uranium. Copyright (2001) Material Research Society

  7. Nuclear

    International Nuclear Information System (INIS)

    Anon.

    2000-01-01

    The first text deals with a new circular concerning the collect of the medicine radioactive wastes, containing radium. This campaign wants to incite people to let go their radioactive wastes (needles, tubes) in order to suppress any danger. The second text presents a decree of the 31 december 1999, relative to the limitations of noise and external risks resulting from the nuclear facilities exploitation: noise, atmospheric pollution, water pollution, wastes management and fire prevention. (A.L.B.)

  8. 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.

  9. Migration and revolution

    Directory of Open Access Journals (Sweden)

    Nando Sigona

    2012-06-01

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

  10. 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

  11. [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.

  12. Underground radionuclide migration at the Nevada Test Site

    International Nuclear Information System (INIS)

    Nimz, G.J.; Thompson, J.L.

    1992-01-01

    This document reviews results from a number of studies concerning underground migration of radionuclides from nuclear test cavities at the Nevada Test Site (NTS). Discussed are all cases known to the Department of Energy's Hydrology and Radionuclide Migration Program where radionuclides have been detected outside of the immediate vicinity of nuclear test cavities that are identifiable as the-source of the nuclides, as well as cases where radionuclides might have been expected and were intentionally sought but not fixed. There are nine locations where source-identifiable radionuclide migration has been detected, one where migration was purposely induced by pumping, and three where migration might be expected but was not found. In five of the nine cases of non-induced migration, the inferred migration mechanism is prompt fracture injection during detonation. In the other four cases, the inferred migration mechanism is water movement. In only a few of the reviewed cases can the actual migration mechanism be stated with confidence, and the attempt has been made to indicate the level of confidence for each case. References are cited where more information may be obtained. As an aid to future study, this document concludes with a brief discussion of the aspects of radionuclide migration that, as the present review indicates, are not yet understood. A course of action is suggested that would produce a better understanding of the phenomenon of radionuclide migration

  13. Geochemistry and radionuclide migration

    International Nuclear Information System (INIS)

    Isherwood, D.

    1978-01-01

    Theoretically, the geochemical barrier can provide a major line of defense in protecting the biosphere from the hazards of nuclear waste. The most likely processes involved are easily identified. Preliminary investigations using computer modeling techniques suggest that retardation is an effective control on radionuclide concentrations. Ion exchange reactions slow radionuclide migration and allow more time for radioactive decay and dispersion. For some radionuclides, solubility alone may limit concentrations to less than the maximum permissible now considered acceptable by the Federal Government. The effectiveness of the geochemical barrier is ultimately related to the repository site characteristics. Theory alone tells us that geochemical controls will be most efficient in an environment that provides for maximum ion exchange and the precipitation of insoluble compounds. In site selection, consideration should be given to rock barriers with high ion exchange capacity that might also act as semi-permeable membranes. Also important in evaluating the site's potential for effective geochemical controls are the oxidation potentials, pH and salinity of the groundwater

  14. Radionuclide migration in soils

    Energy Technology Data Exchange (ETDEWEB)

    Demir, M [Ingenieurgesellschaft Bonnenberg und Drescher, Juelich (Germany, F.R.)

    1979-01-01

    Unplanned releases from a nuclear installation - e.g., leakage from a storage tank or other incident - can result in the escape of contaminants such as U, Pu, Cs, Sr, T etc. Nuclide transport through the ground is governed by characteristics of the subsurface hydrology and the specific nuclides under consideration. Unsaturated soil layers result in a transport rate so low as to negligible. Radionuclides reaching the ground water are assumed to endanger human life because of potential uncontrolled ingestion. The most dangerous nuclides are long-lived and not absorbed, or very poorly absorbed, in the soil. During migration of nuclides through saturated soil layers, the concentration can be reduced by dilution. Preliminary results indicate that tritium is spread with ground water velocity. Its concentration can be reduced only by diffusion, dispersion and radioactive decay. Alpha-emitters are strongly retained velocities of alpha-emitters are approximately one thousandth (10/sup -3/) that of T. Transport velocities of Cs and Sr are approximately one hundreth (10/sup -2/) and one tenth (10/sup -1/) that of T respectively.

  15. Radionuclide migration in soils

    International Nuclear Information System (INIS)

    Demir, M.

    1979-01-01

    Unplanned releases from a nuclear installation - e.g., leakage from a storage tank or other incident - can result in the escape of contaminants such as U, Pu, Cs, Sr, T etc. Nuclide transport through the ground is governed by characteristics of the subsurface hydrology and the specific nuclides under consideration. Unsaturated soil layers result in a transport rate so low as to negligible. Radionuclides reaching the ground water are assumed to endanger human life because of potential uncontrolled ingestion. The most dangerous nuclides are long-lived and not absorbed, or very poorly absorbed, in the soil. During migration of nuclides through saturated soil layers, the concentration can be reduced by dilution. Preliminary results indicate that tritium is spread with ground water velocity. Its concentration can be reduced only by diffusion, dispersion and radioactive decay. Alpha-emitters are strongly retained velocities of alpha-emitters are approximately one thousandth (10 -3 ) that of T. Transport velocities of Cs and Sr are approximately one hundreth (10 -2 ) and one tenth (10 -1 ) that of T respectively. (orig./HP) [de

  16. Migration of gases through argillaceous rocks

    International Nuclear Information System (INIS)

    Tomlinson, M.J.

    1988-11-01

    Research literature relating to laboratory and field experimentation and numerical modelling of gas transport in argillaceous geological materials has been examined. A data base has been formed to assist simulation of gas migration behaviour from proposed underground nuclear waste repositories. (author)

  17. Deep ground water microbiology in Swedish granite rock and it's relevance for radio-nuclide migration from a Swedish high level nuclear waste repository

    International Nuclear Information System (INIS)

    Pedersen, Karsten

    1989-03-01

    Data on numbers, species and activity of deep ground water microbial populations in Swedish granite rock have been collected. Specific studies are performed on radio-nuclid uptake on bacteria judge to be probable inhabitants in Swedish nuclear waste repositories. An integrated mobile field laboratory was used for water sampling and for the immediate counting and inoculation of the samples from boreholes at levels between 129 and 860 m. A sampler adapted for the collection of undisturbed samples for gas analysis was used to collect samples for bacterial enumerations and enrichments. The sampler can be opened and closed from the surface at the actual sampling depth. The samples can subsequently be brought to the surface without contact with air and with the pressure at the actual sampling depth. The number of bacteria were determined in samples from the gas sampler when this was possible. Else numbers are determined in the water that is pumped up to the field lab. The average total number of bacteria is 3 x 10 5 bacterial ml -1 . The number of bacteria possible to recover with plate count arrays from 0.10 to 21.9%. (author)

  18. Nuclear radiation and agricultural production - the food chain as a pathway for radionuclide (toxic trace elements) migration from the source to the ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Giacintov, P [Statni Veterinarni Ustav, Brno (Czechoslovakia)

    1978-01-01

    The transport of /sup 131/I from the source into the atmosphere, its concentration in the atmosphere above agricultural land, its deposition in the vegetative cover and factors which affect the deposition rate, its retention and the effects of weather conditions are described as an example of the transport of radionuclides from the source to the ecosystem and into the human body. The relation is given for the calculation of the effective half-life of /sup 131/I retention in plants. In steady state during permanent /sup 131/I release the effective life-time is 7.2 days on the average. The transport is described of /sup 131/I from the vegetation into the organism of the cow, into milk and from there into the human body. The intake of /sup 131/I depends on the amount of milk consumed which again depends on age, sex and dietary habits. For children the maximum permissible concentration of /sup 131/I in milk is 15 to 40 pCi/l, based on a dose limit of 90 mrem/y to the thyroid. The knowledge of all factors related to /sup 131/I transport through the food chain to the human body allows determining the permissible level of /sup 131/I release from a nuclear power plant.

  19. Interpreting the deposition and vertical migration characteristics of 137Cs in forest soil after the Fukushima Dai-ichi Nuclear Power Plant accident.

    Science.gov (United States)

    Kang, Seongjoo; Yoneda, Minoru; Shimada, Yoko; Satta, Naoya; Fujita, Yasutaka; Shin, In Hwan

    2017-08-01

    We investigated the deposition and depth distributions of radiocesium in the Takizawa Research Forest, Iwate Prefecture, in order to understand the behavior of radionuclides released from the Fukushima Dai-ichi Nuclear Power Plant. The deposition distribution and vertical depth distribution of radiocesium in the soil were compared between topographically distinct parts of the forest where two different tree species grow. The results for all investigated locations show that almost 85% of the radiocesium has accumulated in the region of soil from the topmost organic layer to a soil depth of 0-4 cm. However, no activity was detected at depths greater than 20 cm. Analysis of the radiocesium deposition patterns in forest locations dominated by either coniferous or deciduous tree species suggests that radiocesium was sequestered and retained in higher concentrations in coniferous areas. The deposition data showed large spatial variability, reflecting the differences in tree species and topography. The variations in the measured 137 Cs concentrations reflected the variability in the characteristics of the forest floor environment and the heterogeneity of the initial ground-deposition of the Fukushima fallout. Sequential extraction experiments showed that most of the 137 Cs was present in an un-exchangeable form with weak mobility. Nevertheless, the post-vertical distribution of 137 Cs is expected to be governed by the percentage of exchangeable 137 Cs in the organic layer and the organic-rich upper soil horizons.

  20. Simulation of bentonite colloid migration through granite

    International Nuclear Information System (INIS)

    Rosicka, Dana; Hokr, Milan

    2012-01-01

    Document available in extended abstract form only. Full text of publication follows: Colloidal bentonite particles generate at the interface of buffer and host rock in spent nuclear fuel repository due to an erosion process and migrate through granite by the water flow. Stability of these colloids and their migration possibilities have been studied on account of radionuclide transport possibility as colloid could carry adsorbed radionuclides in groundwater through granite. That is why a simulation of bentonite colloid migration in the surrounding of a repository might be requested. According to chemical condition as ionic strength and pH, the colloidal particles coagulate into clusters and that influence the migration of particles. The coagulation kinetics of natural bentonite colloids were experimentally studied in many articles, for example by light scattering techniques. We created a model of coagulation of bentonite colloids and simulation of a chosen experiment with use of the multicomponent reactive transport equation. The coagulation model describes clustering of particles due to attractive van der Waals forces as result of collision of particles due to heat fluctuation and different velocity of particles during sedimentation and velocity gradient of water flow. Next, the model includes influence of repulsive electrostatic forces among colloidal particles leading to stability of particles provided high surface charge of colloids. In the model, each group of clusters is transported as one solution component and the kinetics of coagulation are implemented as reactions between the components: a shift of particles among groups of particles with similar migration properties, according to size of the clusters of colloids. The simulation of migration of bentonite colloid through granite using the coagulation model was calibrated according to experiment results. On the basis of the simulation, one can estimate the basic processes that occur during bentonite colloid

  1. 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

  2. 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...

  3. Regional Redistribution and Migration

    DEFF Research Database (Denmark)

    Manasse, Paolo; Schultz, Christian

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

  4. Reconstitution of fluid paleo-circulations and element migrations in the environments of Oklo's natural nuclear reactors (Gabon) and of Tournemire's argillites (France)

    International Nuclear Information System (INIS)

    Mathieu, Regis

    1999-01-01

    To better characterize the mobilization and migration process in rocks, a petrological and geochemical study of fluid paleo-circulation through fractures has been made in two different sites: (1) The environment of natural nuclear reactors from Proterozoic Oklo uranium ores (Gabon). The Archean basement typical of TTG series and the sandstones-pelites series of the Franceville basin are affected by a fracturing mainly filled by quartz-daphnite-calcite-sulfides and barren ou mineralized bitumens. Three paragenetic stages has been correlated to three regional structural phases. During the first extensional phase, a low saline (1.7-6.5 wt% NaCl), heated in the basement (190-210 deg. C) and impoverished in 18 O meteoric recharge is injected into the basin, along major N-S faults. It was responsible of silicification. The circulation of diagenetic brines is able to leach U, Pb, Zr, REEs and P resulting from accessory minerals alteration, at the basin-scale between 2104 Ma and 1719 Ma (Pb/Pb isochrone obtained on galena incorporated in zircons). These brines are responsible of anomalous Th/La ratios (1.8) of FA silicified sandstones higher than those (0.25) of most of Archean and Proterozoic metasediments. They are highly chlorine, calco-sodic ([Cl] > 6 m, from 28 wt% NaCl to 30 wt% CaCl 2 ), equilibrated with carbonate and evaporitic layers of FA sandstones, with low temperatures (130 deg. C) and rich in Ca, Li and Br. They are expulsed laterally due to the compaction of FA sandstones, and upwards along sub-vertical fractures. During the second extensional phase, the mineralization stage, mainly controlled by N-S faults corresponds to a mixing (155-220 deg. C) between the brines, the meteoric recharge and hydrocarbons C 9 and C 10 -rich fluids derived from organic matter maturation in the FB pelites. The interaction of the three fluids is responsible of the mineralization in sandstones and in calcites displaying an organic carbon origin (δ 13 C=-10 to -15 0/00 vs. PDB

  5. In situ migration experiment in argillaceous formation

    International Nuclear Information System (INIS)

    Yoshida, Hidekazu

    1990-01-01

    International cooperative R and D has been performed within the five years framework of the bilateral agreement between PNC (Power Reactor and Nuclear Fuel Development Corporation) and SCK/CEN (Studiecentrum voor Kernergie/Centre D'etude de L'energie Nucleaire, Mol, Belgium) which is focused on 'The Migration Experiment in argillaceous formation.' This Tertiary argillaceous formation, called Boom clay, is located at about 230m depth in Mol-Dessel area, Belgium. The argillaceous rock is considered to have a high capability for retardation to radionuclides when they migrate in geosphere because of a high content of clay minerals and dissolved carbon-rich pore water. The main purpose of this collaboration work is to characterize the migration phenomena in sedimentary rock through understanding of the behaviour of radionuclides migration in the argillaceous formation. The present report describes the preliminary results of in situ one-dimensional migration experiment with labelled clay core emplaced in borehole under advective condition. In the experiment, radioactive tracer Sr-85 and Eu-152+154 have been used in order to determine the apparent dispersion coefficient and retardation factor of Boom clay. Finally, the following conclusions were obtained by in situ measurement and calculation based on a appropriate migration model; a) From the Sr-85 experiment, diffusive behavior is interpreted to be a dominant phenomena on radionuclides transportation. b) From the Eu-152+154 experiment, very small non-retarded fraction is observed. (author)

  6. Samtidskunst og migration

    DEFF Research Database (Denmark)

    Petersen, Anne Ring

    2010-01-01

    "Samtidskunst og migration. En oversigt over faglitteraturen" er en forskningsoversigt der gør status over hvad der hidtil er skrevet inden for det kunsthistoriske område om vor tids billedkunst og migration som politisk, socialt og kulturelt fænomen, primært i forbindelse med immigration til...

  7. The Great Migration.

    Science.gov (United States)

    Trotter, Joe William, Jr.

    2002-01-01

    Describes the migration of African Americans in the United States and the reasons why African Americans migrated from the south. Focuses on issues, such as the effect of World War I, the opportunities offered in the north, and the emergence of a black industrial working class. (CMK)

  8. Migrating Art History

    DEFF Research Database (Denmark)

    Ørum, Tania

    2012-01-01

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

  9. College Student Migration.

    Science.gov (United States)

    Fenske, Robert H.; And Others

    This study examines the background characteristics of two large national samples of first-time enrolled freshmen who (a) attended college within their state of residence but away from their home community, (b) migrated to a college in an adjacent state, (c) migrated to a college in a distant state, and (d) attended college in their home community.…

  10. Migration, klima og sundhed

    DEFF Research Database (Denmark)

    Tellier, Siri; Carballo, Manuel

    2009-01-01

    Many tentative connections have been postulated between migration and climate. This article points to rural-urban migration, particularly into low elevation urban slums prone to flooding as an issue needing urgent attention by health professionals. It also notes the no-man's land in which environ...

  11. Migration in Burkina Faso

    NARCIS (Netherlands)

    Wouterse, F.S.

    2007-01-01

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

  12. Migration, Narration, Identity

    DEFF Research Database (Denmark)

    Leese, Peter

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

  13. 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

  14. Malaysia and forced migration

    Directory of Open Access Journals (Sweden)

    Arzura Idris

    2012-06-01

    Full Text Available This paper analyzes the phenomenon of “forced migration” in Malaysia. It examines the nature of forced migration, the challenges faced by Malaysia, the policy responses and their impact on the country and upon the forced migrants. It considers forced migration as an event hosting multifaceted issues related and relevant to forced migrants and suggests that Malaysia has been preoccupied with the issue of forced migration movements. This is largely seen in various responses invoked from Malaysia due to “south-south forced migration movements.” These responses are, however, inadequate in terms of commitment to the international refugee regime. While Malaysia did respond to economic and migration challenges, the paper asserts that such efforts are futile if she ignores issues critical to forced migrants.

  15. Nuclear fuel waste disposal

    International Nuclear Information System (INIS)

    Merrett, G.J.; Gillespie, P.A.

    1983-07-01

    This report discusses events and processes that could adversely affect the long-term stability of a nuclear fuel waste disposal vault or the regions of the geosphere and the biosphere to which radionuclides might migrate from such a vault

  16. Evidence for tension-based regulation of Drosophila MAL and SRF during invasive cell migration.

    Science.gov (United States)

    Somogyi, Kálmán; Rørth, Pernille

    2004-07-01

    Cells migrating through a tissue exert force via their cytoskeleton and are themselves subject to tension, but the effects of physical forces on cell behavior in vivo are poorly understood. Border cell migration during Drosophila oogenesis is a useful model for invasive cell movement. We report that this migration requires the activity of the transcriptional factor serum response factor (SRF) and its cofactor MAL-D and present evidence that nuclear accumulation of MAL-D is induced by cell stretching. Border cells that cannot migrate lack nuclear MAL-D but can accumulate it if they are pulled by other migrating cells. Like mammalian MAL, MAL-D also responds to activated Diaphanous, which affects actin dynamics. MAL-D/SRF activity is required to build a robust actin cytoskeleton in the migrating cells; mutant cells break apart when initiating migration. Thus, tension-induced MAL-D activity may provide a feedback mechanism for enhancing cytoskeletal strength during invasive migration.

  17. Migration and AIDS.

    Science.gov (United States)

    1998-01-01

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

  18. 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

  19. Neuronal Migration Disorders

    Science.gov (United States)

    ... Understanding Sleep The Life and Death of a Neuron Genes At Work In The Brain Order Publications ... birth defects caused by the abnormal migration of neurons in the developing brain and nervous system. In ...

  20. Migration og etnicitet

    DEFF Research Database (Denmark)

    Christiansen, Connie Carøe

    2004-01-01

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

  1. 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.

  2. Repeat migration and disappointment.

    Science.gov (United States)

    Grant, E K; Vanderkamp, J

    1986-01-01

    This article investigates the determinants of repeat migration among the 44 regions of Canada, using information from a large micro-database which spans the period 1968 to 1971. The explanation of repeat migration probabilities is a difficult task, and this attempt is only partly successful. May of the explanatory variables are not significant, and the overall explanatory power of the equations is not high. In the area of personal characteristics, the variables related to age, sex, and marital status are generally significant and with expected signs. The distance variable has a strongly positive effect on onward move probabilities. Variables related to prior migration experience have an important impact that differs between return and onward probabilities. In particular, the occurrence of prior moves has a striking effect on the probability of onward migration. The variable representing disappointment, or relative success of the initial move, plays a significant role in explaining repeat migration probabilities. The disappointment variable represents the ratio of actural versus expected wage income in the year after the initial move, and its effect on both repeat migration probabilities is always negative and almost always highly significant. The repeat probabilities diminish after a year's stay in the destination region, but disappointment in the most recent year still has a bearing on the delayed repeat probabilities. While the quantitative impact of the disappointment variable is not large, it is difficult to draw comparisons since similar estimates are not available elsewhere.

  3. Environmental concentration and migration of 129I

    International Nuclear Information System (INIS)

    Brauer, F.P.; Strebin, R.S. Jr.

    1982-01-01

    Local sources of 129 I suitable for study of migration in the environment are uranium ore bodies for long periods and nuclear fuel reprocessing operations for recent periods. Uranium ores produce 129 I from spontaneous and neutron-induced fission. Nuclear fuel reprocessing has resulted in releases of 129 I to both the atmosphere and the hydrosphere. The long-term fate of surface-deposited and groundwater 129 I was studied. Neutron activation analysis was used to measure the low levels of 129 I and natural 127 I in samples near and remote from nuclear fuel reprocessing facilities. Measurements were made on air samples, vegetation, soil, surface water, groundwater and uranium ore samples. Samples were collected both during reprocessing operations and after reprocessing activities had been discontinued for several years. The 129 I was found to accumulate in the top soil and litter layer. The surface concentrations of 129 I in forest communities were found to be several times higher than for nearby grass communities. The 129 I levels were found to persist in the environment after reprocessing activities had been discontinued. Measurable 129 I was found to be contained in uranium ore samples from a variety of locations and with a range of uranium concentrations. Thus ore bodies constitute a source of 129 I suitable for study of migration over long periods. Iodine-129 has entered surface and groundwater as the result of liquid and atmospheric discharges from nuclear fuel reprocessing facilities. The iodine in water samples was found to be anionic and travel with the water flow. Thus 129 I was found to provide high sensitivity for hydrology tracer studies and radioactivity migration surveillance. Once 129 I enters the hydrosphere it migrates with the water with little or no hold-up by exchange with cationic exchangers such as soil or silt

  4. Managing migration: the Brazilian case

    OpenAIRE

    Eduardo L. G. Rios-Neto

    2005-01-01

    The objective of this paper is to present the Brazilian migration experience and its relationship with migration management. The article is divided into three parts. First, it reviews some basic facts regarding Brazilian immigration and emigration processes. Second, it focuses on some policy and legal issues related to migration. Finally, it addresses five issues regarding migration management in Brazil.

  5. Prestack depth migration

    International Nuclear Information System (INIS)

    Postma, R.W.

    1991-01-01

    Two lines form the southern North Sea, with known velocity inhomogeneities in the overburden, have been pre-stack depth migrated. The pre-stack depth migrations are compared with conventional processing, one with severe distortions and one with subtle distortions on the conventionally processed sections. The line with subtle distortions is also compared with post-stack depth migration. The results on both lines were very successful. Both have already influenced drilling decisions, and have caused a modification of structural interpretation in the respective areas. Wells have been drilled on each of the lines, and well tops confirm the results. In fact, conventional processing led to incorrect locations for the wells, both of which were dry holes. The depth migrated sections indicate the incorrect placement, and on one line reveals a much better drilling location. This paper reports that even though processing costs are high for pre-stack depth migration, appropriate use can save millions of dollars in dry-hole expense

  6. Migration = cloning; aliasiing

    DEFF Research Database (Denmark)

    Hüttel, Hans; Kleist, Josva; Nestmann, Uwe

    1999-01-01

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

  7. 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

  8. En fornemmelse for migration

    DEFF Research Database (Denmark)

    Schütze, Laura Maria

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

  9. Mechanism for transient migration of xenon in UO2

    International Nuclear Information System (INIS)

    Liu, X.-Y.; Uberuaga, B. P.; Andersson, D. A.; Stanek, C. R.; Sickafus, K. E.

    2011-01-01

    In this letter, we report recent work on atomistic modeling of diffusion migration events of the fission gas product xenon in UO 2 nuclear fuel. Under nonequilibrium conditions, Xe atoms can occupy the octahedral interstitial site, in contrast to the thermodynamically most stable uranium substitutional site. A transient migration mechanism involving Xe and two oxygen atoms is identified using basin constrained molecular dynamics employing a Buckingham type interatomic potential. This mechanism is then validated using density functional theory calculations using the nudged elastic band method. An overall reduction in the migration barrier of 1.6-2.7 eV is obtained compared to vacancy-mediated diffusion on the uranium sublattice.

  10. 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

  11. Unix Application Migration Guide

    CERN Document Server

    Microsoft. Redmond

    2003-01-01

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

  12. Migrating for a Profession

    DEFF Research Database (Denmark)

    Olwig, Karen Fog

    2015-01-01

    a strong sense of agency and self-empowerment. In the post-WWII period, numerous Caribbean women trained in nursing at British hospitals that have been described as marred by race and gender related inequality and associated forms of exploitation. Yet, the nurses interviewed about this training emphasised......Youths from the Global South migrating for further education often face various forms of discrimination. This Caribbean case study discusses how conditions in the home country can provide a foundation for educational migration that helps the migrants overcome such obstacles and even develop...... in which it enabled these Caribbean women to stake out a new life for themselves....

  13. Migrating the Light

    DEFF Research Database (Denmark)

    Sørensen, Bent

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

  14. Describing migration spatial structure

    NARCIS (Netherlands)

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

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

  15. Brain Migration Revisited

    Science.gov (United States)

    Vinokur, Annie

    2006-01-01

    The "brain drain/brain gain" debate has been going on for the past 40 years, with irresolvable theoretical disputes and unenforceable policy recommendations that economists commonly ascribe to the lack of reliable empirical data. The recent report of the World Bank, "International migration, remittances and the brain drain", documents the…

  16. Dispersal and migration

    Directory of Open Access Journals (Sweden)

    Schwarz, C.

    2004-06-01

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

  17. Migration and Africa

    DEFF Research Database (Denmark)

    Zoppi, Marco

    2014-01-01

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

  18. Migration as Adventure

    DEFF Research Database (Denmark)

    Olwig, Karen Fog

    2018-01-01

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

  19. 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...

  20. The politicisation of migration

    NARCIS (Netherlands)

    van der Brug, W.; D' Amato, G.; Berkhout, J.; Ruedin, D.

    2015-01-01

    Why are migration policies sometimes heavily contested and high on the political agenda? And why do they, at other moments and in other countries, hardly lead to much public debate? The entrance and settlement of migrants in Western Europe has prompted various political reactions. In some countries

  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. Migration pathways in soils

    International Nuclear Information System (INIS)

    Gronow, J.R.

    1986-01-01

    This study looked at diffusive migration through three types of deformation; the projectile pathways, hydraulic fractures of the sediments and faults, and was divided into three experimental areas: autoradiography, the determination of diffusion coefficients and electron microscopy of model projectile pathways in clay. For the autoradiography, unstressed samples were exposed to two separate isotopes, Pm-147 (a possible model for Am behaviour) and the poorly sorbed iodide-125. The results indicated that there was no enhanced migration through deformed kaolin samples nor through fractured Great Meteor East (GME) sediment, although some was evident through the projectile pathways in GME and possibly through the GME sheared samples. The scanning electron microscopy of projectile pathways in clay showed that emplacement of a projectile appeared to have no effect on the orientation of particles at distances greater than two projectile radii from the centre of a projectile pathway. It showed that the particles were not simply aligned with the direction of motion of the projectile but that, the closer to the surface of a particular pathway, the closer the particles lay to their original orientation. This finding was of interest from two points of view: i) the ease of migration of a pollutant along the pathway, and ii) possible mechanisms of hole closure. It was concluded that, provided that there is no advective migration, the transport of radionuclides through sediments containing these defects would not be significantly more rapid than in undeformed sediments. (author)

  3. International Migration of Couples

    DEFF Research Database (Denmark)

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

    2018-01-01

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

  4. Mechanisms and models of 137Cs migration in soil

    International Nuclear Information System (INIS)

    Frid, A.S.

    1999-01-01

    The most wide-spread mechanisms and models of the 137 Cs isotope migration in soil are considered because of urgency of this problem conditioned by global fallout during nuclear weapon tests and contamination of territories due to accidents on nuclear objects (including the East Urals and ChNPP accident). It is shown that the 137 Cs migration models with an account of the sorption-desorption kinetics have from the practical adequacy certain advantage in comparison with other models, though they are mathematically more complex and require complex calculations [ru

  5. 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

  6. The CHESHIRE Migration Experiment A Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    David A. Sawyer; Joseph L. Thompson; David K. Smith

    1999-10-01

    The CHESHIRE nuclear weapon test was detonated in 1976 in fractured volcanic rock at the Nevada Test Site (NTS). This testis representative of many other high-yield tests conducted below the water table in the Pahute Mesa area of the NTS. Since 1976 we have been studying the movement of test-related radionuclides within a few hundred meters of the explosion cavity. CHESHIRE is the only nuclear test characterized before, immediately after, and for decades following the detonation and provides data on both the prompt and long-term dispersal of radionuclides after an underground nuclear test. For this reason it is a unique field-scale transport experiment. Solid and fluid samples were collected from a drill back hole extending into and through the cavity in order to measure the initial distributions of radionuclides after the detonation. We subsequently pumped and sampled water from the cavity region and from a hydraulically transmissive zone about 400 m higher in the collapse chimney. A satellite well was also drilled 380 m down gradient from CHESHIRE and intercepted radionuclides (including tritium in high concentration) being transported through transmissive aquifers. Studies of radionuclide migration at CHESHIRE documented for the first time at the NTS the transport of relatively insoluble radionuclides (e.g., europium isotopes) with colloids moving in the groundwater. Water was pumped again from the cavity and chimney horizons in 1998 in order to observe the evolution of the hydrologic source term after several decades. Recent comprehensive studies of the geology and hydrology at the CHESHIRE site have improved predictions of radionuclide migration in the context of a regional groundwater flow model. This report provides unclassified data and describes a conceptual model for radionuclide migration associated with a nuclear test that is applicable to other tests on Pahute Mesa similar in yield, hydrogeologic setting, and age.

  7. 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...

  8. THE ROMANIAN MIGRATIONAL EVOLUTION PHENOMENON

    Directory of Open Access Journals (Sweden)

    Cristian Raluca

    2009-05-01

    Full Text Available In our contemporary democratic society the migration phenomenon meets unknown valences in any previous societies. Free will and right to self-determination, much exploited by the XX century society., raised the possibility of interpretation of migration

  9. International migration and the gender

    OpenAIRE

    Koropecká, Markéta

    2010-01-01

    My bachelor thesis explores the connection between international migration and gender. Gender, defined as a social, not a biological term, has a huge impact on the migration process. Statistics and expert studies that have been gender sensitive since 1970s demonstrate that women form half of the amount of the international migrants depending on the world region and representing a wide range of the kinds of international migration: family formation and reunification, labour migration, illegal ...

  10. The commercialization of migration.

    Science.gov (United States)

    Abrera-mangahas, M A

    1989-01-01

    International migration is not new to the Philippines. In the recent outflow of contract workers to the Middle East, there is a shift from individual and family initiated migrations to the more organized, highly commercial variety. While profit-taking intermediaries have played some role in the past, the increase in the number and influence of these intermediaries has altered the story of migration decision-making. In 1975, the signing of the bilateral labor agreement between the governments of Iran and the Philippines signalled the rising demand for Filipino contract workers. From 1970 to 1975, the number of Asian migrant workers in the Gulf countries rose from about 120,000 to 370,000. These figures rose dramatically to 3.3 million in 1985. The growing share of organized and commercialized migration has altered migration decision making. Primarily, intermediaries are able to broaden access to foreign job and high wage opportunities. Commercialization effectively raises the transaction costs for contract migration. Studies on recruitment costs and fees show that self-solicited foreign employment costs less than employment obtained through recruitment agents and intermediaries. The difference in the 2 prices is due, not only to overhead costs of intermediation, but more importantly to the rent exacted by agents from having job information and placement rights. In the Philippines in October 1987 the average placement fee was P8000, greatly exceeding the mandated maximum fee level of P5000. This average is understated because the computation includes the 17% who do not pay any fees. The widespread and popular view of recruitment intermediaries is negative, dominated by images of abuses and victims. Private intermediaries and the government bureaucracy need each other. Intermediaries need government; their consistent demand for incentives and protection is indicative. On the other hand, government expands its supervision of control of overseas employment via the

  11. Youth Labor Migration in Nepal

    OpenAIRE

    Bossavie, Laurent; Denisova, Anastasiya

    2018-01-01

    This descriptive study investigates internal and external labor migration by Nepalese youth. External labor migration is separated into the flow to India, which is unregulated, and the flow to other countries, which typically takes the form of temporary contract migration to countries with bilateral labor agreements with Nepal (referred to in Nepal as foreign employment). The study finds t...

  12. Musei del migration heritage / Migration heritage museums

    Directory of Open Access Journals (Sweden)

    Patrizia Dragoni

    2015-01-01

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

  13. Religion, migration og integration

    DEFF Research Database (Denmark)

    Borup, Jørn

    2010-01-01

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

  14. Grain boundary migration

    International Nuclear Information System (INIS)

    Dimitrov, O.

    1975-01-01

    Well-established aspects of grain-boundary migration are first briefly reviewed (influences of driving force, temperature, orientation and foreign atoms). Recent developments of the experimental methods and results are then examined, by considering the various driving of resistive forces acting on grain boundaries. Finally, the evolution in the theoretical models of grain-boundary motion is described, on the one hand for ideally pure metals and, on the other hand, in the presence of solute impurity atoms [fr

  15. Ventriculoperitoneal Shunt Migration

    Directory of Open Access Journals (Sweden)

    Justin P Puller

    2017-01-01

    Full Text Available History of present illness: A 40-year-old female presented to our ED with left upper abdominal pain and flank pain. The pain had begun suddenly 2 hours prior when she was reaching into a freezer to get a bag of frozen vegetables. She described the pain as sharp, constant, severe, and worse with movements and breathing. The pain radiated to the left shoulder. On review of systems, the patient had mild dyspnea and nausea. She denied fever, chills, headache, vision changes, vomiting, or urinary symptoms. Her medical history was notable for obstructive sleep apnea, gastroesophageal reflux disease, arthritis, fibromyalgia, depression, obesity, and idiopathic intracranial hypertension. For the latter, she had a VP (ventriculoperitoneal shunt placed 14 years prior to this visit. She had a history of 2 shunt revisions, the most recent 30 days before this ED visit. Significant findings: An immediate post-op abdominal x-ray performed after the patient’s VP shunt revision 30 days prior to this ED visit reveals the VP shunt tip in the mid abdomen. A CT of the abdomen performed on the day of the ED visit reveals the VP shunt tip interposed between the spleen and the diaphragm. Discussion: VP shunts have been reported to migrate to varied locations in the thorax and abdomen. Incidence of abdominal complications of VP shunt placement ranges from 10%-30%, and can include pseudocyst formation, migration, peritonitis, CSF ascites, infection, and viscus perforation. Incidence of distal shunt migration is reported as 10%, and most previously reported cases occurred in pediatric patients.1 A recent retrospective review cited BMI greater than thirty and previous shunt procedure as risk factors for distal shunt migration.2 The patient in the case presented had a BMI of 59 and 3 previous shunt procedures.

  16. 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

  17. Many Faces of Migrations

    Directory of Open Access Journals (Sweden)

    Milica Antić Gaber

    2013-12-01

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

  18. Migration Process Evolution in Europe

    Directory of Open Access Journals (Sweden)

    Carmen Tudorache

    2006-08-01

    Full Text Available The migration phenomenon has always existed, fluctuating by the historic context, the economic, political, social and demographic disparities between the Central and East European countries and the EU Member States, the interdependencies between the origin and receiving countries and the European integration process evolutions. In the European Union, an integrated and inclusive approach of the migration issue is necessary. But a common policy on migration rests an ambitious objective. A common approach of the economic migration management and the harmonization of the migration policies of the Member States represented a challenge for the European Union and will become urgent in the future, especially due to the demographic ageing.

  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. Overview of CEA research in the field of radionuclides migration

    International Nuclear Information System (INIS)

    Poinssot, Ch.; Trotignon, L.; Tevissen, E.

    2006-01-01

    This report presents a synthetic status of the researches conducted within the Nuclear Energy Division (CEA/DEN) in the field of radionuclides migration in three specific areas which have been chosen for their representativeness and potential impact: the migration of RN in PWR reactors, the migration of RN from a deep geological repository and the migration processes in the surface environments. In addition, some status is given about more generic research which is conducted in the field of RN speciation in the aqueous phase and at the interfaces and regarding chemistry / transport couplings. Additional information about the human and technical means involved in these fields of research in CEA/DEN is finally given in the Appendix. (authors)

  1. On the Attosecond charge migration in Cl N, Cl O, Br N and Br O ...

    Indian Academy of Sciences (India)

    Abstract. The electron-electron relaxation and correlation-driven charge migration process, which features pure electronic aspect of ultrafast charge migration phenomenon, occurs on a very short timescale in ionized molecules and molecular clusters, prior to the onset of nuclear motion. In this article, we have presented ...

  2. 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.

  3. 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.

  4. ILO - International Migration Programme.

    Science.gov (United States)

    Boudraa, Miriam

    2011-01-01

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

  5. Urbanization, Migration, Information

    Directory of Open Access Journals (Sweden)

    Konstantin Lidin

    2016-05-01

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

  6. 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...

  7. Network migration for printers

    CERN Multimedia

    2016-01-01

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

  8. MIGRATION AND ITS ENVIROMENTAL EFFECTS

    OpenAIRE

    Rashid SAEED; Rana NADIR IDREES; Humna IJAZ; Marriam FURQANI; Raziya NADEEM

    2012-01-01

    Migration can be ongoing shifting of a particular person from one location to another. The reason of shifting depends on selected thought deficiency, shock, difficulties, hopes, enthusiasm. Case study ended up recognizing the extent to which in turn migration can be relying on the specifics especially natural environment. This particular document expects to research the actual linkages between the atmosphere as well as migration using secondary data. Lots of investigation may be completed wit...

  9. Nordic Migration and Integration Research

    OpenAIRE

    Pyrhönen, Niko; Martikainen, Tuomas; Leinonen, Johanna

    2017-01-01

    EXECUTIVE SUMMARY Migration and integration are currently highly contentious topics in political, public and scientific arenas, and will remain so in the near future. However, many common migration-related prejudices and inefficien¬cies in the integration of the migrant population are due to the lack of sound, tested and accessible scientific research. Therefore, the study of migration – by developing basic research and by properly resourcing novel methodological approaches and interventions ...

  10. The challenges of managing migration

    Energy Technology Data Exchange (ETDEWEB)

    Tacoli, Cecilia

    2005-10-15

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

  11. Characterisation of contamination migration in the workplace

    International Nuclear Information System (INIS)

    Boulaud, D.; Laborde, J.C.; Pourprix, M.

    1994-01-01

    The Institute for Nuclear Safety and Protection (IPSN) has developed a procedure for characterising airborne contamination between processes and the workplace in nuclear facilities. It was initially intended to use this process to validate operator choices concerning the monitoring of indoor air contamination (personnel monitoring, and environmental detection at fixed locations), but also to optimise the fundamental parameters which have a more or less direct influence on potential exposure of staff in the workplace (at the same time optimising the contamination source, close confinement, process ventilation and general ventilation). In practice, the methods used to obtain these expert appraisals were usually based on experiments carried out in situ: (i) characterisation of aerosol contamination by accurate measurement of the nature, concentration and particle size distribution at various locations; (ii) characterisation of the migration of contamination by precise measurement involving gas and/or particle tracing techniques. In parallel with these experiments, a considerable effort was made to develop and qualify computer codes capable of predicting or estimating the migration of contamination through complex ventilated areas, by means of both fluid mechanics and aerosol science. (Author)

  12. 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 ...

  13. Migration and regional inequality

    DEFF Research Database (Denmark)

    Peng, Lianqing; Swider, Sarah

    2017-01-01

    Scholars studying economic inequality in China have maintained that regional inequality and economic divergence across provinces have steadily increased over the past 30 years. New studies have shown that this trend is a statistical aberration; calculations show that instead of quickly and sharply...... rising, regional inequality has actually decreased, and most recently, remained stable. Our study suggests that China’s unique migratory regime is crucial to understanding these findings. We conduct a counterfactual simulation to demonstrate how migration and remittances have mitigated income inequality...... across provinces in order to show that without these processes, we would have seen more of a rise in interprovincial income inequality. We conclude by arguing that inequality in China is still increasing, but it is changing and becoming less place-based. As regional inequality decreases, there are signs...

  14. Tracking migrating birds

    DEFF Research Database (Denmark)

    Willemoes, Mikkel

    habitats with those in rural habitats. Some species have decreased the frequency of migrants and migration distance in urban environments, and others have not. The other manuscript describes the small scale movements of three different Palaearctic migrants during winter in Africa in a farmland habitat....... In another species, environmental conditions are not a good predictor of movements, and possibly effects of timing constraints or food type play a role. Two manuscripts focus on the effects of human-induced habitat alterations on migratory behaviour. One compares the movements of partial migrants in urban...... and a forest reserve. In the degraded habitat all species used more space, although the consequence on bird density is less clear. Two manuscripts relate the migratory movements of a long-distance migrant with models of navigation. One compares model predictions obtained by simulation with actual movements...

  15. Making Migration Meaningful

    DEFF Research Database (Denmark)

    Benwell, Ann Fenger

    2013-01-01

    a way to escape family patriarchy and conformity, and can contribute to loss, hardship, and uncertainty for family members left behind. Further, mobility provides opportunities and a means to escape the stigma of ‘laziness’ culturally associated with poverty and immobility. Postsocialist separation has...... of absence by migrant family members, as both men and women are culturally permitted to be separate from their families. Migration is understood to contribute to prosperity, and separations contribute to generate growth and hishig (good fortune) for the good of the family. However, such mobility is also......Mongolia has experienced two decades since the demise of the Soviet Union and has implemented strategies to strengthen its economy and its democratic practices. Transitions from being a nomadic society to a Soviet satellite state and onwards to liberal democracy have greatly impacted family life...

  16. Nightly Test system migration

    CERN Document Server

    Win-Lime, Kevin

    2013-01-01

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

  17. Migration: the trends converge.

    Science.gov (United States)

    1985-09-01

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

  18. Stochastic analysis of radionuclide migration in saturated-unsaturated soils

    International Nuclear Information System (INIS)

    Kawanishi, Moto

    1988-01-01

    In Japan, LLRW (low level radioactive wastes) generated from nuclear power plants shall be started to store concentrically in the Shimokita site from 1990, and those could be transformed into land disposal if the positive safety is confirmed. Therefore, it is hoped that the safety assessment method shall be successed for the land disposal of LLRW. In this study, a stochastic model to analyze the radionuclide migration in saturated-unsaturated soils was constructed. The principal results are summarized as follows. 1) We presented a generalized idea for the modeling of the radionuclide migration in saturated-unsaturated soils as an advective-dispersion phenomena followed by the decay of radionuclides and those adsorption/desorption in soils. 2) Based on the radionuclide migration model mentioned above, we developed a stochastic analysis model on radionuclide migration in saturated-unsaturated soils. 3) From the comparison between the simulated results and the exact solution on a few simple one-dimensional advective-dispersion problems of radionuclides, the good validity of this model was confirmed. 4) From the comparison between the simulated results by this model and the experimental results of radionuclide migration in a one-dimensional unsaturated soil column with rainfall, the good applicability was shown. 5) As the stochastic model such as this has several advantages that it is easily able to represent the image of physical phenomena and has basically no numerical dissipation, this model should be more applicable to the analysis of the complicated radionuclide migration in saturated-unsaturated soils. (author)

  19. Challenged by migration: Europe's options

    NARCIS (Netherlands)

    Constant, Amelie F.; Zimmermann, Klaus F.

    2017-01-01

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

  20. Radionuclide migration studies in soil

    International Nuclear Information System (INIS)

    Marumo, J.T.

    1989-01-01

    In this work a brief description about retention and migration parameters of radionuclides in soil, including main methods to determine the distribution coefficient (K) are given. Some of several factors that can act on the migration are also mentioned. (author) [pt

  1. South-South Migration and Remittances

    OpenAIRE

    Ratha, Dilip; Shaw, William

    2007-01-01

    South-South Migration and Remittances reports on preliminary results from an ongoing effort to improve data on bilateral migration stocks. It sets out some working hypotheses on the determinants and socioeconomic implications of South-South migration. Contrary to popular perception that migration is mostly a South-North phenomenon, South-South migration is large. Available data from nation...

  2. 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.

  3. Wages, Welfare Benefits and Migration.

    Science.gov (United States)

    Kennan, John; Walker, James R

    2010-05-01

    Differences in economic opportunities give rise to strong migration incentives, across regions within countries, and across countries. In this paper we focus on responses to differences in welfare benefits across States. We apply the model developed in Kennan and Walker (2008), which emphasizes that migration decisions are often reversed, and that many alternative locations must be considered. We model individual decisions to migrate as a job search problem. A worker starts the life-cycle in some home location and must determine the optimal sequence of moves before settling down. The model is sparsely parameterized. We estimate the model using data from the National Longitudinal Survey of Youth (1979). Our main finding is that income differences do help explain the migration decisions of young welfare-eligible women, but large differences in benefit levels provide surprisingly weak migration incentives.

  4. 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

  5. Migrating and herniating hydatid cysts

    International Nuclear Information System (INIS)

    Koc, Zafer; Ezer, Ali

    2008-01-01

    Objective: To present the prevalence and imaging findings of patients with hydatid disease (HD) showing features of migration or herniation of the hydatid cysts (HCs) and underline the clinical significance of this condition. Materials and methods: Between May 2003 and June 2006, 212 patients with HD were diagnosed by abdomen and/or thorax CT, searched for migrating or herniating HC. Imaging findings of 7 patients (5 women, 2 men with an age range of 19-63 years; mean ± S.D., 44 ± 19 years) with HD showing transdiaphragmatic migration (6 subjects) or femoral herniation (1 subject) were evaluated. Diagnosis of all the patients were established by pathologic examination and migration or herniation was confirmed by surgery in all patients. Results: Liver HD were identified in 169 (79.7%) of 212 patients with HD. Transdiaphragmatic migration of HCs were identified in 6 (3.5%) of the 169 patients with liver HD. In one patient, femoral herniation of the retroperitoneal HC into the proximal anterior thigh was identified. All of these seven patients exhibiting migration or herniation of HCs had active HCs including 'daughter cysts'. Two patients had previous surgery because of liver HD and any supradiaphragmatic lesion was not noted before operation. Findings of migration or herniation were confirmed by surgery. Conclusion: Active HCs may show migration or herniation due to pressure difference between the anatomic cavities, and in some of the patients, by contribution of gravity. Previous surgery may be a complementary factor for migration as seen in two of our patients. The possibility of migration or herniation in patients with HD should be considered before surgery

  6. 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.

  7. NNDC database migration project

    Energy Technology Data Exchange (ETDEWEB)

    Burrows, Thomas W; Dunford, Charles L [U.S. Department of Energy, Brookhaven Science Associates (United States)

    2004-03-01

    NNDC Database Migration was necessary to replace obsolete hardware and software, to be compatible with the industry standard in relational databases (mature software, large base of supporting software for administration and dissemination and replication and synchronization tools) and to improve the user access in terms of interface and speed. The Relational Database Management System (RDBMS) consists of a Sybase Adaptive Server Enterprise (ASE), which is relatively easy to move between different RDB systems (e.g., MySQL, MS SQL-Server, or MS Access), the Structured Query Language (SQL) and administrative tools written in Java. Linux or UNIX platforms can be used. The existing ENSDF datasets are often VERY large and will need to be reworked and both the CRP (adopted) and CRP (Budapest) datasets give elemental cross sections (not relative I{gamma}) in the RI field (so it is not immediately obvious which of the old values has been changed). But primary and secondary intensities are now available on the same scale. The intensity normalization has been done for us. We will gain access to a large volume of data from Budapest and some of those gamma-ray intensity and energy data will be superior to what we already have.

  8. Psychosocial Aspects of Migration

    Directory of Open Access Journals (Sweden)

    Ayla Tuzcu

    2014-02-01

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

  9. 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.

  10. 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.

  11. 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 ...

  12. Glycine Receptor α2 Subunit Activation Promotes Cortical Interneuron Migration

    Directory of Open Access Journals (Sweden)

    Ariel Avila

    2013-08-01

    Full Text Available Glycine receptors (GlyRs are detected in the developing CNS before synaptogenesis, but their function remains elusive. This study demonstrates that functional GlyRs are expressed by embryonic cortical interneurons in vivo. Furthermore, genetic disruption of these receptors leads to interneuron migration defects. We discovered that extrasynaptic activation of GlyRs containing the α2 subunit in cortical interneurons by endogenous glycine activates voltage-gated calcium channels and promotes calcium influx, which further modulates actomyosin contractility to fine-tune nuclear translocation during migration. Taken together, our data highlight the molecular events triggered by GlyR α2 activation that control cortical tangential migration during embryogenesis.

  13. [The productive structure and migration].

    Science.gov (United States)

    Fernandez, M

    1980-01-01

    The author discusses the possibility of determining the proper approach to the study of migration, with a focus on the importance of global, structural, and historical analysis of the phenomenon. A general theoretical outline is presented that tends to show migration as an integral part of the process of social change. The sociological focus on modernization as a theoretical guide influencing the study of migration in Latin America is evaluated. The concept of overpopulation is explained in relation to the migratory process, with reference to capitalist and non-capitalist forms of production.

  14. 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.

  15. MIGRATION – EFFECTS AND SOLUTIONS

    Directory of Open Access Journals (Sweden)

    Raluca Cruceru

    2012-12-01

    Full Text Available There are three main flows that influence workforce performance—worker migration, the dissemination of knowledge, and overseas development assistance. For the present paper we decided to deal with the analyses of these three, yet mainly migration. We considered it to be one of the most important phenomenon existent on the market at this hour and with the highest negative impact on the economic and social situation. We presented a case study regarding the situation of migration in Romania and the main candidates to Romanian intelligence imports, the main issues and possible solutions to the problems encountered.

  16. MRI of neuronal migration disorders

    International Nuclear Information System (INIS)

    Engelbrecht, V.

    1996-01-01

    Twenty-one MRI examinations of the brain were performed in 19 children with neuronal migration disorders. Multiplanar oriented spin-echo sequences were on a scanner with 1.5 T. In 8 children we performed an additional turbo-inversion recovery (TIR) sequence. Results of sonography or CT from five children were compared with MRI scans. Using the actual nomenclature, we found the following migration disorders: Lissencephaly (n=6), cobblestone lissencephaly with Walker-Warbung syndrome (WWS) (n=2), polymicrogyria and schizencephaly (n=2), focal heterotopia (n=5), diffuse heterotopie (n=2) and hemimegalencephaly (n=2). MRI was superior to CT and sonography in all children. Except for the two boys with WWS, the TIR sequence was the best to demonstrate the changes in migration disorder because of the high contrast between gray and white matter. We demonstrate the characteristic features of the different migration disorders and compare them with the existing literature. (orig.) [de

  17. The migration challenge for PAYG

    Czech Academy of Sciences Publication Activity Database

    Aslanyan, Gurgen

    2014-01-01

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

  18. The migration challenge for PAYG

    Czech Academy of Sciences Publication Activity Database

    Aslanyan, Gurgen

    2014-01-01

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

  19. Labour market frictions and migration

    NARCIS (Netherlands)

    Cremers, Jan

    2016-01-01

    The 4th contribution to the series INT-AR papers is dedicated to the methods of assessing labour market frictions. The paper provides a (brief) international comparison of the role of labour migration in solving these frictions.

  20. Effort Estimation in BPMS Migration

    Directory of Open Access Journals (Sweden)

    Christopher Drews

    2018-04-01

    Full Text Available Usually Business Process Management Systems (BPMS are highly integrated in the IT of organizations and are at the core of their business. Thus, migrating from one BPMS solution to another is not a common task. However, there are forces that are pushing organizations to perform this step, e.g. maintenance costs of legacy BPMS or the need for additional functionality. Before the actual migration, the risk and the effort must be evaluated. This work provides a framework for effort estimation regarding the technical aspects of BPMS migration. The framework provides questions for BPMS comparison and an effort evaluation schema. The applicability of the framework is evaluated based on a simplified BPMS migration scenario.

  1. Return Migration and Working Choices

    OpenAIRE

    TANI, Massimiliano; MAHUTEAU, Stéphane

    2008-01-01

    Collective Action to Support the Reintegration of Return Migrants in their Country of Origin (MIREM) This paper uses the recent survey carried out in the framework of the MIREM project on returnees to Algeria, Morocco and Tunisia and studies the duration of emigration and the labour force status upon returning. The results suggest that age and the year of emigration play a central role in the migration decision, but they do not support the hypothesis that the duration of migration is deter...

  2. Roosts and migrations of swallows

    OpenAIRE

    Winkler, David W.

    2006-01-01

    Swallows of the north temperate zone display a wide variety of territorial behaviour during the breeding season, but as soon as breeding is over, they all appear to adopt a pattern of independent diurnal foraging interleaved with aggregation every night in dense roosts. Swallows generally migrate during the day, feeding on the wing. On many stretches of their annual journeys, their migrations can thus be seen as the simple spatial translation of nocturnal roost sites with foraging routes stra...

  3. International Student Migration to Germany

    OpenAIRE

    Donata Bessey

    2007-01-01

    This paper presents first empirical evidence on international student migration to Germany. I use a novel approach that analyzes student mobility using an augmented gravity equation and find evidence of strong network effects and of the importance of distance - results familiar from the empirical migration literature. However, the importance of disposable income in the home country does not seem to be too big for students, while the fact of being a politically unfree country decreases migrati...

  4. Effort Estimation in BPMS Migration

    OpenAIRE

    Drews, Christopher; Lantow, Birger

    2018-01-01

    Usually Business Process Management Systems (BPMS) are highly integrated in the IT of organizations and are at the core of their business. Thus, migrating from one BPMS solution to another is not a common task. However, there are forces that are pushing organizations to perform this step, e.g. maintenance costs of legacy BPMS or the need for additional functionality. Before the actual migration, the risk and the effort must be evaluated. This work provides a framework for effort estimation re...

  5. Confinement and migration of radionuclides in deep geological disposal

    International Nuclear Information System (INIS)

    Poinssot, Ch.

    2007-07-01

    Disposing high level nuclear waste in deep disposal repository requires to understand and to model the evolution of the different repository components as well as radionuclides migration on time-frame which are well beyond the time accessible to experiments. In particular, robust and predictive models are a key element to assess the long term safety and their reliability must rely on a accurate description of the actual processes. Within this framework, this report synthesizes the work performed by Ch. Poinssot and has been prepared for the defense of his HDR (French university degree to Manage Research). These works are focused on two main areas which are (i) the long term evolution of spent nuclear fuel and the development of radionuclide source terms models, and (ii) the migration of radionuclides in natural environment. (author)

  6. Palaearctic-African Bird Migration

    DEFF Research Database (Denmark)

    Iwajomo, Soladoye Babatola

    Bird migration has attracted a lot of interests over past centuries and the methods used for studying this phenomenon has greatly improved in terms of availability, dimension, scale and precision. In spite of the advancements, relatively more is known about the spring migration of trans-Saharan m......Bird migration has attracted a lot of interests over past centuries and the methods used for studying this phenomenon has greatly improved in terms of availability, dimension, scale and precision. In spite of the advancements, relatively more is known about the spring migration of trans...... of birds from Europe to Africa and opens up the possibility of studying intra-African migration. I have used long-term, standardized autumn ringing data from southeast Sweden to investigate patterns in biometrics, phenology and population trends as inferred from annual trapping totals. In addition, I...... in the population of the species. The papers show that adult and juvenile birds can use different migration strategies depending on time of season and prevailing conditions. Also, the fuel loads of some individuals were theoretically sufficient for a direct flight to important goal area, but whether they do so...

  7. Investigation on nuclide migration behaviors

    International Nuclear Information System (INIS)

    Baik, Minhoon; Park, Chungkyun; Kim, Seungsoo

    2012-04-01

    In this study, we investigated the properties of geochemical reactions and sorption of high-level radionuclides and highly-mobile radionuclides in deep geological disposal environments. We also analyzed the dissolution properties of pyro wastes and constructed databases for the geochemical reactions and sorption for the safety assessment of HLW disposal. Technologies for measuring diffusion depths of radionuclides through fracture surfaces and rock matrix were developed in KURT conditions and their diffusion properties were analyzed and evaluated. The combined reactions of radionuclide/mineral/microbe in deep disposal environments were investigated and the effects of microbe on the radionuclide migration and disposal system behaviors were evaluated. In-situ solute migration system and on-line monitoring system were installed in KURT and the migration and retardation behaviors of various solutes and their interaction with fracture-filling materials were investigated. Basic properties of KURT groundwater colloids were analyzed using various methods. In addition, in-situ colloid migration experiments through a rock fracture were carried out and the developed migration model was verified. We have participated in Colloid Formation and Migration (CFM) international joint project in GTS and obtained reliability for our research results by comparing research results each other

  8. Migration of radionuclides following shallow land burial

    International Nuclear Information System (INIS)

    Sedlet, J.; Golchert, N.W.

    1980-01-01

    A study of radionuclide migration was conducted at a facility used from 1944 to 1949 for the shallow land burial of radwaste produced during operations with two reactors and related nuclear research. It is situated in glacial drift 45 m thick. Underlying the drift is a generally level Silurian dolomite bedrock 60 m thick. The thickness of the drift decreases as the surface slopes downhill (north) until the dolomite reaches the surface and forms the bed of a river, 700 m to the north. This study was begun after tritiated water was detected in two picnic wells north of the facility, between the burial plot and the river. Surface and subsurface measurements indicate that tritium is migrating out of the burial site, but no other radionuclides have left the plot. The tritium concentrations decrease with distance from the plot. Tritium was found in the subsoil at all depths sampled, so the ground beneath and immediately around the plot contains tritium down to the dolomite aquifer. Time of travel of water from the burial plot to the nearest well is estimated to be 54 months. This would imply the peak concentration would reach the dolomite in about 35 years. By this time, 86% of the tritium would have disappeared by radioactive decay. The cyclical nature of the tritium content in the two wells implies that tritiated water is carried from the burial site by the spring rains when they recharge the groundwater supply

  9. Radionuclide migration in the Chernobyl contamination zone

    International Nuclear Information System (INIS)

    Golosov, V.N.; Panin, A.V.; Ivanova, N.N.

    1998-01-01

    It is well known that fallout of 137 Cs reaching the land soils with precipitation was rapidly and tightly sorbed to the fine fraction of sediment or soils. The majority of the 137 Cs is retained in the top few centimetres of the soil or sediment profiles (Loughran et al, 1993, Owens et al, 1996). In the absence of strong variations in precipitation over a relatively small area the total bomb-derived 137 Cs fallout can assumed to be spatial uniform. The Chernobyl 137 Cs fallout was mostly connected with one or two rains. So the spatial variability of this 137 Cs can be higher. Furthermore because the explosion on the Chernobyl nuclear plant happen together with fire, a lot of ashes particles with radionuclide were distributed within vast areas. So even microvariability of Chernobyl 137 Cs can be very high in some places. The horizontal migration of 137 Cs connects with soil erosion processes that dominate on the agricultural lands of the Central Russia. The main goal of this investigation is to evaluate the caesium-137 horizontal and vertical migration within typical landscape of the Central Russia 11 years after the Chernobyl accident

  10. Migration of ATLAS PanDA to CERN

    International Nuclear Information System (INIS)

    Stewart, Graeme Andrew; Klimentov, Alexei; Maeno, Tadashi; Nevski, Pavel; Nowak, Marcin; De Castro Faria Salgado, Pedro Emanuel; Wenaus, Torre; Koblitz, Birger; Lamanna, Massimo

    2010-01-01

    The ATLAS Production and Distributed Analysis System (PanDA) is a key component of the ATLAS distributed computing infrastructure. All ATLAS production jobs, and a substantial amount of user and group analysis jobs, pass through the PanDA system, which manages their execution on the grid. PanDA also plays a key role in production task definition and the data set replication request system. PanDA has recently been migrated from Brookhaven National Laboratory (BNL) to the European Organization for Nuclear Research (CERN), a process we describe here. We discuss how the new infrastructure for PanDA, which relies heavily on services provided by CERN IT, was introduced in order to make the service as reliable as possible and to allow it to be scaled to ATLAS's increasing need for distributed computing. The migration involved changing the backend database for PanDA from MySQL to Oracle, which impacted upon the database schemas. The process by which the client code was optimised for the new database backend is discussed. We describe the procedure by which the new database infrastructure was tested and commissioned for production use. Operations during the migration had to be planned carefully to minimise disruption to ongoing ATLAS offline computing. All parts of the migration were fully tested before commissioning the new infrastructure and the gradual migration of computing resources to the new system allowed any problems of scaling to be addressed.

  11. 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

  12. 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.

  13. Nuclear Reaction and Structure Databases of the National Nuclear Data Center

    International Nuclear Information System (INIS)

    Pritychenko, B.; Arcilla, R.; Herman, M. W.; Oblozinsky, P.; Rochman, D.; Sonzogni, A. A.; Tuli, J. K.; Winchell, D. F.

    2006-01-01

    The National Nuclear Data Center (NNDC) collects, evaluates, and disseminates nuclear physics data for basic research and applied nuclear technologies. In 2004, the NNDC migrated all databases into modern relational database software, installed new generation of Linux servers and developed new Java-based Web service. This nuclear database development means much faster, more flexible and more convenient service to all users in the United States. These nuclear reaction and structure database developments as well as related Web services are briefly described

  14. Investigation on migration of Uranium in solidified materials

    International Nuclear Information System (INIS)

    Bai Yun; Zhu Xiaohong; Yang Guangwen; Liao Junsheng; Shuai Zhenqing

    2011-01-01

    The sorption and migration behaviors of uranium in soils and cement were studied by column test. The results show that the sorption ratio of soil is bigger than that of cement. Specific radioactivity of 235 U in the soil and cement samples is basically the same as that of environmental soil, and specific radioactivity of 235 U varies little with the sampling depth. The results should provide valuable information to nuclear facility decommissioning. (authors)

  15. The terminal basal mitosis of chicken retinal Lim1 horizontal cells is not sensitive to cisplatin-induced cell cycle arrest.

    Science.gov (United States)

    Shirazi Fard, Shahrzad; Thyselius, Malin; All-Ericsson, Charlotta; Hallböök, Finn

    2014-01-01

    For proper development, cells need to coordinate proliferation and cell cycle-exit. This is mediated by a cascade of proteins making sure that each phase of the cell cycle is controlled before the initiation of the next. Retinal progenitor cells divide during the process of interkinetic nuclear migration, where they undergo S-phase on the basal side, followed by mitoses on the apical side of the neuroepithelium. The final cell cycle of chicken retinal horizontal cells (HCs) is an exception to this general cell cycle behavior. Lim1 expressing (+) horizontal progenitor cells (HPCs) have a heterogenic final cell cycle, with some cells undergoing a terminal mitosis on the basal side of the retina. The results in this study show that this terminal basal mitosis of Lim1+ HPCs is not dependent on Chk1/2 for its regulation compared to retinal cells undergoing interkinetic nuclear migration. Neither activating nor blocking Chk1 had an effect on the basal mitosis of Lim1+ HPCs. Furthermore, the Lim1+ HPCs were not sensitive to cisplatin-induced DNA damage and were able to continue into mitosis in the presence of γ-H2AX without activation of caspase-3. However, Nutlin3a-induced expression of p21 did reduce the mitoses, suggesting the presence of a functional p53/p21 response in HPCs. In contrast, the apical mitoses were blocked upon activation of either Chk1/2 or p21, indicating the importance of these proteins during the process of interkinetic nuclear migration. Inhibiting Cdk1 blocked M-phase transition both for apical and basal mitoses. This confirmed that the cyclin B1-Cdk1 complex was active and functional during the basal mitosis of Lim1+ HPCs. The regulation of the final cell cycle of Lim1+ HPCs is of particular interest since it has been shown that the HCs are able to sustain persistent DNA damage, remain in the cell cycle for an extended period of time and, consequently, survive for months.

  16. NEW WEB-BASED ACCESS TO NUCLEAR STRUCTURE DATASETS.

    Energy Technology Data Exchange (ETDEWEB)

    WINCHELL,D.F.

    2004-09-26

    As part of an effort to migrate the National Nuclear Data Center (NNDC) databases to a relational platform, a new web interface has been developed for the dissemination of the nuclear structure datasets stored in the Evaluated Nuclear Structure Data File and Experimental Unevaluated Nuclear Data List.

  17. Confinement and migration of radionuclides in deep geological disposal; Confinement et migration des radionucleides en stockage geologique profond

    Energy Technology Data Exchange (ETDEWEB)

    Poinssot, Ch

    2007-07-15

    Disposing high level nuclear waste in deep disposal repository requires to understand and to model the evolution of the different repository components as well as radionuclides migration on time-frame which are well beyond the time accessible to experiments. In particular, robust and predictive models are a key element to assess the long term safety and their reliability must rely on a accurate description of the actual processes. Within this framework, this report synthesizes the work performed by Ch. Poinssot and has been prepared for the defense of his HDR (French university degree to Manage Research). These works are focused on two main areas which are (i) the long term evolution of spent nuclear fuel and the development of radionuclide source terms models, and (ii) the migration of radionuclides in natural environment. (author)

  18. Migration of radionuclide chains through an adsorbing medium

    International Nuclear Information System (INIS)

    Lester, D.H.; Jansen, G.; Burkholder, H.C.

    1974-12-01

    The migration of actinides and other radionuclides from an underground geologic nuclear waste disposal site through a soil column to a surface water body was investigated for impulse and band releases. Numerical calculation of the analytical solutions revealed that differences in adsorption characteristics between chain members, axial dispersion, and radioactive decay all act to reduce radionuclide discharge rates at the exit of the soil column. The results of the study may have important implications in the underground storage and disposal of nuclear waste. (U.S.)

  19. Nuclear waste

    International Nuclear Information System (INIS)

    1989-01-01

    This paper reviews the Department of Energy's management of underground single-shell waste storage tanks at its Hanford, Washington, site. The tanks contain highly radioactive and nonradioactive hazardous liquid and solid wastes from nuclear materials production. Hundreds of thousands of gallons of these wastes have leaked, contaminating the soil, and a small amount of leaked waste has reached the groundwater. DOE does not collect sufficient data to adequately trace the migration of the leaks through the soil, and studies predicting the eventual environmental impact of tank leaks do not provide convincing support for DOE's conclusion that the impact will be low or nonexistent. DOE can do more to minimize the environmental risks associated with leaks. To reduce the environmental impact of past leaks, DOE may be able to install better ground covering over the tanks to reduce the volume of precipitation that drains through the soil and carries contaminants toward groundwater

  20. International migration: a global challenge.

    Science.gov (United States)

    Martin, P; Widgren, J

    1996-04-01

    Trends in international migration are presented in this multiregional analysis. Seven of the world's wealthiest countries have about 33% of the world's migrant population, but under 16% of the total world population. Population growth in these countries is substantially affected by the migrant population. The migration challenge is external and internal. The external challenge is to balance the need for foreign labor and the commitment to human rights for those migrants seeking economic opportunity and political freedom. The internal challenge is to assure the social adjustment of immigrants and their children and to integrate them into society as citizens and future leaders. Why people cross national borders and how migration flows are likely to evolve over the next decades are explained. This report also presents some ways that countries can manage migration or reduce the pressures which force people to migrate. It is recommended that receiving nations control immigration by accelerating global economic growth and reducing wars and human rights violations. This report examines the impact of immigration on international trade, aid, and direct intervention policies. Although migration is one of the most important international economic issues, it is not coordinated by an international group. The European experience indicates that it is not easy to secure international cooperation on issues that affect national sovereignty. It is suggested that countries desiring control of their borders should remember that most people never cross national borders to live or work in another country, that 50% of the world's migrants move among developing countries, and that countries can shift from being emigration to immigration countries. The author suggests that sustained reductions in migration pressure are a better alternative than the "quick fixes" that may invite the very much feared mass and unpredictable movements.

  1. Radionuclides migration or isolation?

    International Nuclear Information System (INIS)

    Toulhoat, P.; Grambow, B.; Simoni, E.

    2005-01-01

    After 20 years of research, the chemical behaviour of actinides and fission products in nuclear waste disposal environments is much better understood. Consistent thermodynamic data have been gathered and allow much more accurate previsions. Through the considerable development of analytical spectroscopy, including time resolved laser fluorescence and X ray absorption, a better understanding of the chemical reactivity (complexation, sorption) of actinides and fission products at a molecular scale has been possible. Chemically reducing conditions are found in most selected disposal host rock formations, generally chosen for their high sorption capacity (clays); such conditions favour the chemical confinement of most radionuclides through precipitation or sorption. Low permeability host rocks participate to this confinement, as convective fluxes are lower than diffusive fluxes. The most recent performance assessment exercises have taken into account the recent progress of knowledge in the chemical evolution of the near field. They show that the dose rates at the outlet are far lower than existing recommendations for normal and most altered evolution scenarios. (authors)

  2. Nuclear law - Nuclear safety

    International Nuclear Information System (INIS)

    Pontier, Jean-Marie; Roux, Emmanuel; Leger, Marc; Deguergue, Maryse; Vallar, Christian; Pissaloux, Jean-Luc; Bernie-Boissard, Catherine; Thireau, Veronique; Takahashi, Nobuyuki; Spencer, Mary; Zhang, Li; Park, Kyun Sung; Artus, J.C.

    2012-01-01

    This book contains the contributions presented during a one-day seminar. The authors propose a framework for a legal approach to nuclear safety, a discussion of the 2009/71/EURATOM directive which establishes a European framework for nuclear safety in nuclear installations, a comment on nuclear safety and environmental governance, a discussion of the relationship between citizenship and nuclear, some thoughts about the Nuclear Safety Authority, an overview of the situation regarding the safety in nuclear waste burying, a comment on the Nome law with respect to electricity price and nuclear safety, a comment on the legal consequences of the Fukushima accident on nuclear safety in the Japanese law, a presentation of the USA nuclear regulation, an overview of nuclear safety in China, and a discussion of nuclear safety in the medical sector

  3. International nurse migrations: Global trends

    Directory of Open Access Journals (Sweden)

    Ivković Marija

    2011-01-01

    Full Text Available This paper presents global trends of migration of nurses, as specific qualified personnel in high demand. In the last couple of decades, and especially in the last couple of years, many countries have faced the problem of insufficient healthcare workers, particularly nurses. Reasons for this occurrence might be found in the deficiencies of their education systems, as well as the population aging of northern and western countries. As a response to this deficiency, those countries have begun intensive recruitment of foreign qualified female healthcare workers, which has led to the point that nurse migration today presents a very intense, and by many accounts specific migration flow. Female migrating work force is often in pursuit of low-wage and lowqualified work. Nurse migration is actually an example of motion of qualified female migrants in pursuit for better employment opportunities. While such a way of filling up the vacant positions works for the “importing” countries as a temporary solution, departure of trained female personnel presents a significant loss for the originating countries. In this paper we pay special attention to the countries who are the main “importers”, but also to those who are “exporters” of nursing personnel, and to specific national strategies these countries have applied.

  4. Confocal μ-XRF, μ-XAFS, and μ-XRD Studies of Sediment from a Nuclear Waste Disposal Natural Analogue Site and Fractured Granite Following a Radiotracer Migration Experiment

    International Nuclear Information System (INIS)

    Denecke, Melissa A.; Brendebach, Boris; Rothe, Joerg; Simon, Rolf; Janssens, Koen; Nolf, Wout de; Vekemans, Bart; Falkenberg, Gerald; Somogyi, Andrea; Noseck, Ulrich

    2007-01-01

    Combined μ-XRF, μ-XAFS, and μ-XRD investigations of a uranium-rich tertiary sediment, from a nuclear repository natural analogue site, and a fractured granite bore core section after a column tracer experiment using a Np(V) containing cocktail have been performed. Most μ-XRF/μ-XAFS measurements are recorded in a confocal geometry to provide added depth information. The U-rich sediment results show uranium to be present as a tetravalent phosphate and that U(IV) is associated with As(V). Arsenic present is either As(V) or As(0). The As(0) forms thin coatings on the surface of pyrite nodules. A hypothesis for the mechanism of uranium immobilization is proposed, where arsenopyrite acted as reductant of ground water dissolved U(VI) leading to precipitation of less soluble U(IV) and thereby forming As(V). Results for the granite sample show the immobilized Np to be tetravalent and associated with facture material

  5. Rural migration in Nevada: Lincoln County. Phase 1, 1992--1993

    Energy Technology Data Exchange (ETDEWEB)

    Soden, D.L.; Carns, D.E.; Mosser, D.; Conary, J.S.; Ansell, J.P.

    1993-12-31

    The principal objective of this project was to develop insight into the scope of migration of working age Nevadans out of their county of birth; including the collection of data on their skill levels, desire to out or in-migrate, interactions between families of migratory persons, and the impact that the proposed high-level nuclear waste repository at Yucca mountain might have on their individual, and collective, decisions to migrate and return. The initial phase of this project reported here was conducted in 1992 and 1993 in Lincoln County, Nevada, one of the counties designated as ``affected`` by the proposed repository program. The findings suggest that a serious out-migration problem exists in Lincoln County, and that the Yucca mountain project will likely affect decisions relating to migration patterns in the future.

  6. Recommendations for the determination of migration parameters by field experiments (tracer tests)

    International Nuclear Information System (INIS)

    Adam, C.

    1989-01-01

    The hydrogeologic review and assessment of candidate sites for nuclear power plants includes expertises on the potential subsurface migration of radionuclides in the event of accident conditions. To this end, knowledge of representative migration parameters is required. Detailed recommendations are given for determining such parameters by tracer field tests, for using standardized terminology in their practical conduct as well as for interpreting the data obtained. Also, mention has been made of recent work reported by other authors on this topic. 31 refs. (author)

  7. Thermal-gradient migration of brine inclusions in salt crystals

    International Nuclear Information System (INIS)

    Yagnik, S.K.

    1982-09-01

    It has been proposed that high-level nuclear waste be disposed in a geologic repository. Natural-salt deposits, which are being considered for this purpose, contain a small volume fraction of water in the form of brine inclusions distributed throughout the salt. Radioactive-decay heating of the nuclear wastes will impose a temperature gradient on the surrounding salt which mobilizes the brine inclusions. Inclusions filled completely with brine migrate up the temperature gradient and eventually accumulate brine near the buried waste forms. The brine may slowly corrode or degrade the waste forms which is undesirable. In this work, thermal gradient migration of both all-liquid and gas-liquid inclusions was experimentally studied in synthetic single crystals of NaCl and KCl using a hot-stage attachment to an optical microscope which was capable of imposing temperature gradients and axial compressive loads on the crystals. The migration velocities of the inclusions were found to be dependent on temperature, temperature gradient, and inclusion shape and size. The velocities were also dictated by the interfacial mass transfer resistance at brine/solid interface. This interfacial resistance depends on the dislocation density in the crystal, which in turn, depends on the axial compressive loading of the crystal. At low axial loads, the dependence between the velocity and temperature gradient is non-linear.At high axial loads, however, the interfacial resistance is reduced and the migration velocity depends linearly on the temperature gradient. All-liquid inclusions filled with mixed brines were also studied. For gas-liquid inclusions, three different gas phases (helium, air and argon) were compared. Migration studies were also conducted on single crystallites of natural salt as well as in polycrystalline natural salt samples. The behavior of the inclusions at large angle grain boundaries was observed. 35 figures, 3 tables

  8. Thermal gradient migration of brine inclusions in salt crystals

    International Nuclear Information System (INIS)

    Yagnik, S.K.

    1982-01-01

    Natural salt deposits, which are being considered for high-level nuclear wastes repositories, contain a small volume fraction of water in the form of brine inclusions distributed throughout the salt. Radioactive decay heating of the nuclear wastes will impose a temperature gradient on the surrounding salt which mobilizes the brine inclusions. Inclusions filled completely with brine (the all-liquid inclusions) migrate up the temperature gradient and eventually accumulate brine near the buried waste forms. The brine may slowly corrode or degrade the waste forms which is undesirable. In the present work, thermal gradient migration of both all-liquid and gas-liquid inclusions was experimentally studied in synthetic single crystals of NaCl and KCl using a hot-stage attachment to an optical microscope which was capable of imposing temperature gradients and axial compressive loads on the crystals. The migration velocities of the inclusions were found to be dependent on temperature, temperature gradient, and inclusion shape and size. The velocities were also dictated by the interfacial mass transfer resistance at brine/solid interface. This interfacial resistance depends on the dislocation density in the crystal, which in turn, depends on the axial compressive loading of the crystal. At low axial loads, the dependence between the velocity and temperature gradient is nonlinear. At high axial loads, however, the interfacial resistance is reduced and the migration velocity depends linearly on the temperature gradient. All-liquid inclusions filled with mixed brines were also studied. For gas-liquid inclusions, three different gas phases (helium, air and argon) were compared. Migration studies were also conducted on single crystallites of natural salt as well as in polycrystalline natural salt samples. The behavior of the inclusions at large angle grain boudaries was observed

  9. Rural migration and health care

    DEFF Research Database (Denmark)

    Svendsen, Gunnar Lind Haase; Jensen, Marit Vatn

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

  10. 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...

  11. Focus: Asian migration to Canada.

    Science.gov (United States)

    Kobayashi, A

    1988-01-01

    This collection of 5 short essays on Asian migration to Canada focuses on the relationships between individual migrants and their social contexts, both Asian and Canadian. Papers by Anderson and Kobayashi adopt research perspectives of outsider and insider, respectively. Vibert provides a historical overview against which the substantive issues introduced in the other 3 papers can be understood, and he illustrates the links between circumstances of migration and the larger issues by which the course of Canadian social progress has been steered. Mercer provides an introduction to issues that dominate the agenda of contemporary research, to show that Canadian communities of Asian heritage continue to grow in size, diversity, and complexity, as they become more established on the Canadian landscape. This collection is as much about the geography of racism as it is about migration.

  12. 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.

  13. Adenomatous polyposis coli is required for early events in the normal growth and differentiation of the developing cerebral cortex

    Directory of Open Access Journals (Sweden)

    Price David J

    2009-01-01

    Full Text Available Abstract Background Adenomatous polyposis coli (Apc is a large multifunctional protein known to be important for Wnt/β-catenin signalling, cytoskeletal dynamics, and cell polarity. In the developing cerebral cortex, Apc is expressed in proliferating cells and its expression increases as cells migrate to the cortical plate. We examined the consequences of loss of Apc function for the early development of the cerebral cortex. Results We used Emx1Cre to inactivate Apc specifically in proliferating cerebral cortical cells and their descendents starting from embryonic day 9.5. We observed reduction in the size of the mutant cerebral cortex, disruption to its organisation, and changes in the molecular identity of its cells. Loss of Apc leads to a decrease in the size of the proliferative pool, disrupted interkinetic nuclear migration, and increased apoptosis. β-Catenin, pericentrin, and N-cadherin proteins no longer adopt their normal high concentration at the apical surface of the cerebral cortical ventricular zone, indicating that cell polarity is disrupted. Consistent with enhanced Wnt/β-catenin signalling resulting from loss of Apc we found increased levels of TCF/LEF-dependent transcription and expression of endogenous Wnt/β-catenin target genes (Axin2 (conductin, Lef1, and c-myc in the mutant cerebral cortex. In the Apc mutant cerebral cortex the expression of transcription factors Foxg1, Pax6, Tbr1, and Tbr2 is drastically reduced compared to normal and many cells ectopically express Pax3, Wnt1, and Wt1 (but not Wnt2b, Wnt8b, Ptc, Gli1, Mash1, Olig2, or Islet1. This indicates that loss of Apc function causes cerebral cortical cells to lose their normal identity and redirect to fates normally found in more posterior-dorsal regions of the central nervous system. Conclusion Apc is required for multiple aspects of early cerebral cortical development, including the regulation of cell number, interkinetic nuclear migration, cell polarity, and

  14. Migration of radionuclides through a river system

    Energy Technology Data Exchange (ETDEWEB)

    Matsunaga, Takeshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1999-03-01

    Migration behavior of several atmospherically-derived radionuclides in a river watershed was studied. A main interest was in their relocation from the ground soil of the watershed to a downstream region through a river. Studied radionuclides are: {sup 137}Cs generated by weapon tests in the atmosphere; {sup 210}Pb and {sup 7}Be of naturally occurring radionuclides; {sup 137}Cs, {sup 90}Sr, {sup 239,240}Pu and {sup 241}Am released by the Chernobyl nuclear power plant accident. Dominance of the form in suspended solid in river water (particulate form) was qualified for the radionuclides in the Kuji river watershed. An importance of discharge in flooding was also confirmed. A historical budget analysis for weapon test derived {sup 137}Cs was presented for the Hi-i river watershed and its accompanied lake sediment (Lake Shinji). The work afforded a scheme of a fate of {sup 137}Cs after falling on the ground soil and on the lake surface. Several controlling factors, which can influence on the chemical form of radionuclides discharged to a river, were also investigated in the vicinity of the Chernobyl nuclear power plant. A special attention was paid on the association of the radionuclides with dissolved species in water. Preferential association of Pu and Am isotopes to a large molecular size of dissolved matrices, probably of humic substances, was suggested. (author)

  15. Migration of cochlear lateral wall cells.

    Science.gov (United States)

    Dunaway, George; Mhaskar, Yashanad; Armour, Gary; Whitworth, Craig; Rybak, Leonard

    2003-03-01

    The role of apoptosis and proliferation in maintenance of cochlear lateral wall cells was examined. The methods employed for detection of apoptosis were the Hoechst fluorescence stain and TUNEL (TdT-mediated dUTP-biotin nick-end-labeling) assay, and proliferations were 5-bromo-2'-deoxyuridine (BrdU) incorporation and presence of the proliferating cell nuclear antigen. The incidence of apoptosis in the strial marginal cell was 50% greater (32.9+/-3.7%) than strial intermediate and basal cells but similar to spiral ligament cells. Although division of marginal strial cells was rarely detected, a significant number of proliferating cells in the remaining stria vascularis and spiral ligament were observed. These data implied that replacement of marginal cells arose elsewhere and could be followed by a BrdU-deoxythymidine pulse-chase study. At 2 h post injection, nuclear BrdU in marginal cells was not detected; however, by 24 h post injection, 20-25% of marginal cell nuclei were BrdU-positive. These observations are consistent with the hypothesis that marginal cells were replaced by underlying cells. Cell migration appears to be an important mechanism for preserving the function and structure of the stria vascularis.

  16. 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...

  17. Voluntary income redistribution with migration.

    Science.gov (United States)

    Crane, R

    1992-01-01

    This study is concerned with the welfare magnet problem, in which disparities in transfer policies across states are believed to encourage recipient and possibly resource migration. "This study clarifies the terms of the debate by showing how the value of redistributing local resources depends not only on the value of income to each group, but also on the cost of the transfer in erosion of the resource base through migration and through the general equilibrium effects of such activity on local prices." The geographical focus is on the United States. excerpt

  18. Women’s football migration

    DEFF Research Database (Denmark)

    Agergaard, Sine

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

  19. 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.

  20. Retirement migration and military retirement

    International Nuclear Information System (INIS)

    1988-06-01

    This report addresses questions relevant to a socioeconomic assessment system for southern Nevada. They point to an understanding of the magnitude of impacts which may occur if the Yucca Mountain Project were to affect the decision-making process which leads these groups to migrate to southern Nevada. This is an important but somewhat elusive topic lacking in standard data sources. However, the topic may be addressed and analyzed systematically. This report presents the results of efforts to develop a data base and begin development of a model to address the migration, income and expenditure dimensions of these groups. 1 fig., 62 tabs

  1. Automation of Flexible Migration Workflows

    Directory of Open Access Journals (Sweden)

    Dirk von Suchodoletz

    2011-03-01

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

  2. State-of-the-art review of brine migration studies in salt. Technical memorandum report RSI-0075

    International Nuclear Information System (INIS)

    Gnirk, P.F.; Krause, W.B.; Fossum, A.F.

    1981-09-01

    This report provides a state-of-the-art review of brine migration studies in rock salt. Emphasis is placed on the review of literature relating to brine migration phenomena around nuclear waste canisters. This review includes experimental work which has been conducted in the laboratory and in the field. In addition to the literature review, some additional thoughts on brine migration are given and a series of laboratory experiments is proposed. The proposed laboratory experiments are designed to determine whether or not a relationship exists between brine migration and temperature, temperature gradient and stress in rock salt. 34 references, 9 figures, 3 tables

  3. [International migration in the Middle East].

    Science.gov (United States)

    Beauge, G

    1985-01-01

    This special issue contains a selection of 12 papers by various authors on aspects of international migration to the Middle East. Papers are included on the impact of migration on socioeconomic development, income distribution, and rural capitalization in Egypt; migration from rural Lebanon; the effect of emigration on Pakistan; Indian workers in Oman; inter-Arab migration and development; the role of the state in migration in the Arab peninsula; the dynamics of manpower in Kuwait; the Iraqi model and Arab unity; and the impact of this migration on the concept of the New Economic Order.

  4. Labour Force Migration Effects within European Union

    Directory of Open Access Journals (Sweden)

    Carmen Mihaela Tudorache

    2006-10-01

    Full Text Available Within the EU, there is no common policy on migration; there are common policies on certain aspects of migration. The Member States fear of migration, but their economies and societies will further need migrant workers. Labour force migration have positive, but also negative consequences for all parties involved: receiving countries, origin countries and migrant workers. Within this framework, a common approach of the migration management and the harmonization of the economic migration policies of the Member States represent already one of the most important challenges for the European Union and will be further emphasized.

  5. Overview of CEA research in the field of radionuclides migration; Syntheses des recherches menees par le CEA sur la migration des radionucleides

    Energy Technology Data Exchange (ETDEWEB)

    Poinssot, Ch; Trotignon, L; Tevissen, E

    2006-07-01

    This report presents a synthetic status of the researches conducted within the Nuclear Energy Division (CEA/DEN) in the field of radionuclides migration in three specific areas which have been chosen for their representativeness and potential impact: the migration of RN in PWR reactors, the migration of RN from a deep geological repository and the migration processes in the surface environments. In addition, some status is given about more generic research which is conducted in the field of RN speciation in the aqueous phase and at the interfaces and regarding chemistry / transport couplings. Additional information about the human and technical means involved in these fields of research in CEA/DEN is finally given in the Appendix. (authors)

  6. Measuring attitudes towards unauthorized migration

    NARCIS (Netherlands)

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

    2008-01-01

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

  7. 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

  8. Job Migration: A Collaborative Effort

    Science.gov (United States)

    Wagoner, Cynthia L.

    2012-01-01

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

  9. Migration monitoring with automated technology

    Science.gov (United States)

    Rhonda L. Millikin

    2005-01-01

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

  10. [Migration of dentists within Hungary].

    Science.gov (United States)

    Balázs, Péter

    2010-09-01

    Concerning the human resource management in the health care, Hungarian analysts focus mainly on cross-national migration, which was instigated considerably by joining the European Union in 2004. Contrasted to other health care professionals, dentists emphasized also the importance of in-country migration (mobility) indicating serious dangers of developing inequalities in the dental service. From the point of view of health system planning, the main problem is to balance the needs and the number of professionals in regions and areas with extremely different socio-economic conditions. Under dictatorial governments, this "balancing" (which was experienced also in Hungary) is a forced allocation of young professionals to the target regions. In political freedom and free market economy, these measures are unthinkable. The present domestic area distribution, concerning also the supply through vacancies by old age inactivity and cross-national migration, is ruled by personal decisions of actually graduated and immigrant professionals respectively. Therefore, it is unavoidable to investigate the interrelation of factors (dentists' births place, study migration and decisions for practice allocation) ruling the in-country geographic patterns of dental practices. This evidence-based knowledge can only explain the present situation and provide guidelines for health policy decision makers.

  11. Liquid chromatography in migration studies

    International Nuclear Information System (INIS)

    Carlsen, L.; Batsberg, W.

    1982-01-01

    Liquid chromatography ahs been suggested as a facile experimental technique to determine important physico-chemical properties, as permeability, porosity, dispersion-, diffusion-, and sorption charcteristics for geological material as chalk samples. The feasibility of the trechnique as a rapid method to evaluate the possible influence of changes in ground water composition on the migration behavior of radionuclides has been demonstrated

  12. Marriage migration in the Netherlands

    NARCIS (Netherlands)

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

    2014-01-01

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

  13. 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.

  14. Les questions de migrations internationales

    Science.gov (United States)

    Samman, Mouna Liliane

    1993-03-01

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

  15. [Haitian migration to Santo Domingo].

    Science.gov (United States)

    Latortue, P R

    1985-01-01

    This work examines the history of Haitian migration to the Dominican Republic, the central role of Haitian migration in Dominican society, working conditions of Haitian migrants in the Dominican Republic, and the relationship of the migration to economic development on the island of Hispaniola. Lack of data, the difficulty of measuring illegal movement, and the problem of defining Haitians in Santo Domingo have impeded understanding of migration to the Dominican Republic. It is believed by many authorities that Haitian migration to Santo Domingo is considerable and perhaps exceeds that to the US. Haitian migration to the Dominican Republic began after 1915 with the fall of the Haitian president, a worsening of economic conditions partly caused by stagnation in the agricultural sector, and the newly dominant role of the US in Haitian economic affairs. The Great Depression of the 1930s was a direct antecedent of the massacre of Haitians by Dominican police in which some 30 thousand persons were killed; the economic recession of the early 1980s has also caused an outburst of antiHaitian feeling in the Dominican Republic although 80% of laborers in the sugar industry are Haitians. Sugar is extremely important to the Dominican economy: in 1974, sugar covered 12% of cultivated land, produced 40% of foreign exchange earnings, and was responsable for 21% of taxable income. Dominicans however refuse to work in sugar plantations under the current technological. conditions and wage system. Although the government periodically demands the Dominicanization of the sugar work force, no such changes have been made. Sugar will probably continue to play a decisive role in the generation of foreign exchange despite introduction of more technologically advanced sectors which benefit from better prices in the international market. Possibilities of mechanizing sugar production in the Dominican Republic appear remote, and failure to modernize an important sector of the economy has

  16. Sedimentary record of erg migration

    Science.gov (United States)

    Porter, M. L.

    1986-06-01

    The sedimentary record of erg (eolian sand sea) migration consists of an idealized threefold division of sand-sea facies sequences. The basal division, here termed the fore-erg, is composed of a hierarchy of eolian sand bodies contained within sediments of the flanking depositional environment. These sand bodies consist of eolian strata deposited by small dune complexes, zibars, and sand sheets. The fore-erg represents the downwind, leading edge of the erg and records the onset of eolian sedimentation. Basin subsidence coupled with erg migration places the medial division, termed the central erg, over the fore-erg strata. The central erg, represented by a thick accumulation of large-scale, cross-stratified sandstone, is the product of large draa complexes. Eolian influence on regional sedimentation patterns is greatest in the central erg, and most of the sand transported and deposited in the erg is contained within this region. Reduction in sand supply and continued erg migration will cover the central-erg deposits with a veneer of back-erg deposits. This upper division of the erg facies sequence resembles closely the fore-erg region. Similar types of eolian strata are present and organized in sand bodies encased in sediments of the upwind flanking depositional environment(s). Back-erg deposits may be thin due to limited eolian influence on sedimentation or incomplete erg migration, or they may be completely absent because of great susceptibility to postdepositional erosion. Tectonic, climatic, and eustatic influences on sand-sea deposition will produce distinctive variations or modifications of the idealized erg facies sequence. The resulting variants in the sedimentary record of erg migration are illustrated with ancient examples from western North America, Europe, southern Africa, and South America.

  17. [Migration patterns of health professionals].

    Science.gov (United States)

    Kingma, Mireille

    2005-01-01

    The past three decades have seen the number of international migrants double, to reach the unprecedented total of 175 million people in 2003. National health systems are often the biggest national employer, responsible for an estimated 35 million workers worldwide. Health professionals are part of the expanding global labour market. Today, foreign-educated health professionals represent more than a quarter of the medical and nursing workforces of Australia, Canada, the United Kingdom and the United States. Destination countries, however, are not limited to industrialised nations. For example, 50 per cent of physicians in the Namibia public services are expatriates and South Africa continues to recruit close to 80% of its rural physicians from other countries. International migration often imitates patterns of internal migration. The exodus from rural to urban areas, from lower to higher income urban neighbourhoods and from lower-income to higher-income sectors contributes challenges to the universal coverage of the population. International migration is often blamed for the dramatic health professional shortages witnessed in the developing countries. A recent OECD study, however, concludes that many registered nurses in South Africa (far exceeding the number that emigrate) are either inactive or unemployed. These dire situations constitute a modern paradox which is for the most part ignored. Shared language, promises of a better quality of life and globalization all support the continued existence of health professionals' international migration. The ethical dimension o this mobility is a sensitive issue that needs to be addressed. A major paradigm shift, however, is required in order to lessen the need to migrate rather than artificially curb the flows.

  18. Mediterranean Migrations: Regionalisms Versus Globalisation

    Directory of Open Access Journals (Sweden)

    Martin Baldwin-Eduards

    2004-06-01

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

  19. Migration of plutonium and americium in the lithosphere

    International Nuclear Information System (INIS)

    Fried, S.; Friedman, A.M.; Hines, J.J.; Atcher, R.W.; Quarterman, L.A.; Volesky, A.

    1976-01-01

    When radionuclides are stored as wastes either in permanent repositories or in waste storage areas, the possibility of escape into the environment must be considered. Surface contamination and the transport and migration of radionuclides into the lithosphere through the agency of water are discussed. Water in the form of rain will inevitably wash contaminants into soils and thence into conducting rocks. The migration of radionuclides must follow widely varying paths. In porous rocks, water percolates easily under a slight pressure gradient and rapid movement of large volumes of water can result with concommitant transport of large amounts of contaminating materials. In relatively non-porous rocks such as Niagara limestones the transport meets much more resistance and the volumes of water conducted are correspondingly reduced. In such situations much of the migration of water and its solutes may be through cracks and fissures in the rock. Certain strata of rock or rock products may be almost impervious to flow of water and by this token may be considered to be an especially suitable container for long term safe storage of nuclear wastes, particularly if these strata are quiescent. A series of investigations was undertaken to examine the properties of rocks in acting as a retarding agent in the migration of radionuclides. The rocks that are discussed are Niagara limestone (chosen for its density and fine porosity), basalt from the National Reactor Test site, and Los Alamos tuff

  20. Nucleus and nucleus-cytoskeleton connections in 3D cell migration

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Lingling, E-mail: liulingling2012@163.com; Luo, Qing, E-mail: qing.luo@cqu.edu.cn; Sun, Jinghui, E-mail: sunjhemail@163.com; Song, Guanbin, E-mail: song@cqu.edu.cn

    2016-10-15

    Cell migration plays an important role in many physiological and pathological settings, ranging from embryonic development to cancer metastasis. Currently, accumulating data suggest that cells migrating in three-dimensional (3D) environments show well-defined differences compared to their well-established two-dimensional (2D) counterparts. During 3D migration, the cell body and nucleus must deform to allow cellular passage through the available spaces, and the deformability of the relatively rigid nucleus may constitute a limiting step. Here, we highlight the key evidence regarding the role of the nuclear mechanics in 3D migration, including the molecular components that govern the stiffness of the nucleus and review how the nuclear dynamics are connected to and controlled by cytoskeleton-based migration machinery. Intriguingly, nuclear movement must be coordinated with the cytoskeletal dynamics at the leading and trailing edges, which in turn impact the cytoplasmic dynamics that affect the migration efficiency. Thus, we suggest that alterations in the nuclear structure may facilitate cellular reorganizations that are necessary for efficient migration. - Graphical abstract: Schematic representations of a cell migrating on a 2D substrate and a cell migrating in a 3D extracellular matrix environment. (A) Nucleus-cytoskeleton connections are essential to 3D migration. Mechanical signals are transduced by integrins at the cell surface and channeled to cytoskeletal proteins, which generates prestress. The nucleus-cytoskeleton connections can either act as a stable skeleton to anchor the nuclei or provide active force to move the nuclei. The LINC complex is responsible for the nucleo-cytoskeletal coupling. Nesprins connect the cytoskeletal proteins to the inner nuclear membrane proteins SUN1 and SUN2. The SUN proteins connect to the lamins that form the lamina, which attaches to the chromatin. This physical connectivity transmits the mechanical signals from receptors at

  1. Nucleus and nucleus-cytoskeleton connections in 3D cell migration

    International Nuclear Information System (INIS)

    Liu, Lingling; Luo, Qing; Sun, Jinghui; Song, Guanbin

    2016-01-01

    Cell migration plays an important role in many physiological and pathological settings, ranging from embryonic development to cancer metastasis. Currently, accumulating data suggest that cells migrating in three-dimensional (3D) environments show well-defined differences compared to their well-established two-dimensional (2D) counterparts. During 3D migration, the cell body and nucleus must deform to allow cellular passage through the available spaces, and the deformability of the relatively rigid nucleus may constitute a limiting step. Here, we highlight the key evidence regarding the role of the nuclear mechanics in 3D migration, including the molecular components that govern the stiffness of the nucleus and review how the nuclear dynamics are connected to and controlled by cytoskeleton-based migration machinery. Intriguingly, nuclear movement must be coordinated with the cytoskeletal dynamics at the leading and trailing edges, which in turn impact the cytoplasmic dynamics that affect the migration efficiency. Thus, we suggest that alterations in the nuclear structure may facilitate cellular reorganizations that are necessary for efficient migration. - Graphical abstract: Schematic representations of a cell migrating on a 2D substrate and a cell migrating in a 3D extracellular matrix environment. (A) Nucleus-cytoskeleton connections are essential to 3D migration. Mechanical signals are transduced by integrins at the cell surface and channeled to cytoskeletal proteins, which generates prestress. The nucleus-cytoskeleton connections can either act as a stable skeleton to anchor the nuclei or provide active force to move the nuclei. The LINC complex is responsible for the nucleo-cytoskeletal coupling. Nesprins connect the cytoskeletal proteins to the inner nuclear membrane proteins SUN1 and SUN2. The SUN proteins connect to the lamins that form the lamina, which attaches to the chromatin. This physical connectivity transmits the mechanical signals from receptors at

  2. Nuclear power plant siting

    International Nuclear Information System (INIS)

    Sulkiewicz, M.; Navratil, J.

    The construction of a nuclear power plant is conditioned on territorial requirements and is accompanied by the disturbance of the environment, land occupation, population migration, the emission of radioactive wastes, thermal pollution, etc. On the other hand, a nuclear power plant makes possible the introduction of district heating and increases the economic and civilization activity of the population. Due to the construction of a nuclear power plant the set limits of negative impacts must not be exceeded. The locality should be selected such as to reduce the unfavourable effects of the plant and to fully use its benefits. The decision on the siting of the nuclear power plant is preceded by the processing of a number of surveys and a wide range of documentation to which the given criteria are strictly applied. (B.H.)

  3. Nuclear Mechanics in Disease

    Science.gov (United States)

    Zwerger, Monika; Ho, Chin Yee; Lammerding, Jan

    2015-01-01

    Over the past two decades, the biomechanical properties of cells have emerged as key players in a broad range of cellular functions, including migration, proliferation, and differentiation. Although much of the attention has focused on the cytoskeletal networks and the cell’s microenvironment, relatively little is known about the contribution of the cell nucleus. Here, we present an overview of the structural elements that determine the physical properties of the nucleus and discuss how changes in the expression of nuclear components or mutations in nuclear proteins can affect not only nuclear mechanics but also modulate cytoskeletal organization and diverse cellular functions. These findings illustrate that the nucleus is tightly integrated into the surrounding cellular structure. Consequently, changes in nuclear structure and composition are highly relevant to normal development and physiology and can contribute to many human diseases, such as muscular dystrophy, dilated cardiomyopathy, (premature) aging, and cancer. PMID:21756143

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

    Energy Technology Data Exchange (ETDEWEB)

    Assouline, F.

    2001-07-01

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

  5. X-ray-enhanced cancer cell migration requires the linker of nucleoskeleton and cytoskeleton complex.

    Science.gov (United States)

    Imaizumi, Hiromasa; Sato, Katsutoshi; Nishihara, Asuka; Minami, Kazumasa; Koizumi, Masahiko; Matsuura, Nariaki; Hieda, Miki

    2018-04-01

    The linker of nucleoskeleton and cytoskeleton (LINC) complex is a multifunctional protein complex that is involved in various processes at the nuclear envelope, including nuclear migration, mechanotransduction, chromatin tethering and DNA damage response. We recently showed that a nuclear envelope protein, Sad1 and UNC84 domain protein 1 (SUN1), a component of the LINC complex, has a critical function in cell migration. Although ionizing radiation activates cell migration and invasion in vivo and in vitro, the underlying molecular mechanism remains unknown. Here, we examined the involvement of the LINC complex in radiation-enhanced cell migration and invasion. A sublethal dose of X-ray radiation promoted human breast cancer MDA-MB-231 cell migration and invasion, whereas carbon ion beam radiation suppressed these processes in a dose-dependent manner. Depletion of SUN1 and SUN2 significantly suppressed X-ray-enhanced cell migration and invasion. Moreover, depletion or overexpression of each SUN1 splicing variant revealed that SUN1_888 containing 888 amino acids of SUN1 but not SUN1_916 was required for X-ray-enhanced migration and invasion. In addition, the results suggested that X-ray irradiation affected the expression level of SUN1 splicing variants and a SUN protein binding partner, nesprins. Taken together, our findings supported that the LINC complex contributed to photon-enhanced cell migration and invasion. © 2018 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

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

    African Journals Online (AJOL)

    CIU

    Historically, migration process has been characterized and continues to be .... Mexican migration to the U.S (Massey, Arango, Hugo, Kouaouci, Pellegrino and .... the study destination (Sagbama) according to Independent National Electoral.

  7. Comparative Political Economy and International Migration

    NARCIS (Netherlands)

    Afonso, A.; Devitt, C.

    2016-01-01

    This article provides an overview of the literature connecting comparative political economy and international migration in advanced industrialized countries with a focus on the relationship between labour migration, labour markets and welfare institutions. Immigration flows and policies are

  8. 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

  9. Migration aspirations and migration cultures : A case study of Ukrainian migration towards the European Union

    NARCIS (Netherlands)

    Van Mol, C.; Snel, Erik; Hemmerechts, Kenneth; Timmerman, Christiane

    2018-01-01

    An abundant body of research focused on macrolevel, mesolevel, and microlevel factors explaining why individuals move across international borders. In this paper, we aim to complement the existing literature by exploring how, within a single country, mesolevel factors differently impact migration

  10. Radionuclide migration in crystalline rock fractures

    International Nuclear Information System (INIS)

    Hoelttae, P.

    2002-01-01

    Crystalline rock has been considered as a host medium for the repository of high radioactive spent nuclear fuel in Finland. The geosphere will act as an ultimate barrier retarding the migration of radionuclides to the biosphere if they are released through the technical barriers. Radionuclide transport is assumed to take place along watercarrying fractures, and retardation will occur both in the fracture and within the rock matrix. To be able to predict the transport and retardation of radionuclides in rock fractures and rock matrices, it is essential to understand the different phenomena involved. Matrix diffusion has been indicated to be an important mechanism, which will retard the transport of radionuclides in rock fractures. Both dispersion and matrix diffusion are processes, which can have similar influences on solute breakthrough curves in fractured crystalline rock. In this work, the migration of radionuclides in crystalline rock fractures was studied by means of laboratory scale column methods. The purpose of the research was to gain a better understanding of various phenomena - particularly matrix diffusion - affecting the transport and retardation behaviour of radionuclides in fracture flow. Interaction between radionuclides and the rock matrix was measured in order to test the compatibility of experimental retardation parameters and transport models used in assessing the safety of underground repositories for spent nuclear fuel. Rock samples of mica gneiss and of unaltered, moderately altered and strongly altered tonalite represented different rock features and porosities offering the possibility to determine experimental boundary limit values for parameters describing both the transport and retardation of radionuclides and rock matrix properties. The dominant matrix diffusion behaviour was demonstrated in porous ceramic column and gas diffusion experiments. Demonstration of the effects of matrix diffusion in crystalline rock fracture succeeded for the

  11. The reorientation of cell nucleus promotes the establishment of front-rear polarity in migrating fibroblasts.

    Science.gov (United States)

    Maninová, Miloslava; Klímová, Zuzana; Parsons, J Thomas; Weber, Michael J; Iwanicki, Marcin P; Vomastek, Tomáš

    2013-06-12

    The establishment of cell polarity is an essential step in the process of cell migration. This process requires precise spatiotemporal coordination of signaling pathways that in most cells create the typical asymmetrical profile of a polarized cell with nucleus located at the cell rear and the microtubule organizing center (MTOC) positioned between the nucleus and the leading edge. During cell polarization, nucleus rearward positioning promotes correct microtubule organizing center localization and thus the establishment of front-rear polarity and directional migration. We found that cell polarization and directional migration require also the reorientation of the nucleus. Nuclear reorientation is manifested as temporally restricted nuclear rotation that aligns the nuclear axis with the axis of cell migration. We also found that nuclear reorientation requires physical connection between the nucleus and cytoskeleton mediated by the LINC (linker of nucleoskeleton and cytoskeleton) complex. Nuclear reorientation is controlled by coordinated activity of lysophosphatidic acid (LPA)-mediated activation of GTPase Rho and the activation of integrin, FAK (focal adhesion kinase), Src, and p190RhoGAP signaling pathway. Integrin signaling is spatially induced at the leading edge as FAK and p190RhoGAP are predominantly activated or localized at this location. We suggest that integrin activation within lamellipodia defines cell front, and subsequent FAK, Src, and p190RhoGAP signaling represents the polarity signal that induces reorientation of the nucleus and thus promotes the establishment of front-rear polarity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Nuclear fuels

    International Nuclear Information System (INIS)

    2008-01-01

    The nuclear fuel is one of the key component of a nuclear reactor. Inside it, the fission reactions of heavy atoms, uranium and plutonium, take place. It is located in the core of the reactor, but also in the core of the whole nuclear system. Its design and properties influence the behaviour, the efficiency and the safety of the reactor. Even if it represents a weak share of the generated electricity cost, its proper use represents an important economic stake. Important improvements remain to be made to increase its residence time inside the reactor, to supply more energy, and to improve its robustness. Beyond the economical and safety considerations, strategical questions have to find an answer, like the use of plutonium, the management of resources and the management of nuclear wastes and real technological challenges have to be taken up. This monograph summarizes the existing knowledge about the nuclear fuel, its behaviour inside the reactor, its limits of use, and its R and D tracks. It illustrates also the researches in progress and presents some key results obtained recently. Content: 1 - Introduction; 2 - The fuel of water-cooled reactors: aspect, fabrication, behaviour of UO 2 and MOX fuels inside the reactor, behaviour in loss of tightness situation, microscopic morphology of fuel ceramics and evolution under irradiation - migration and localisation of fission products in UOX and MOX matrices, modeling of fuels behaviour - modeling of defects and fission products in the UO 2 ceramics by ab initio calculations, cladding and assembly materials, pellet-cladding interaction, advanced UO 2 and MOX ceramics, mechanical behaviour of the fuel assembly, fuel during a loss of coolant accident, fuel during a reactivity accident, fuel during a serious accident, fuel management inside reactor cores, fuel cycle materials balance, long-term behaviour of the spent fuel, fuel of boiling water reactors; 3 - the fuel of liquid metal fast reactors: fast neutrons radiation

  13. Nanoparticles migration in fractured rocks and affects on contaminant migration

    Science.gov (United States)

    Missana, Tiziana; Garcia-Gutierrez, Miguel; Alonso, Ursula

    2014-05-01

    In previous studies, the transport behavior of artificial (gold and latex) and natural (smectite clay) colloids, within a planar fracture in crystalline rock, was analyzed. In order to better understand the effects of colloid size, shape and surface charge on nanoparticle migration and especially on filtration processes on natural rock surfaces, different clay colloids and oxide nanoparticles were selected and their transport studied as a function of the residence time. In all the cases, (a fraction of) the nanoparticles travelled in the fracture as fast as or faster than water (with a retardation factor, Rf ≤ 1) and the observed Rf, was related to the Taylor dispersion coefficient, accounting for colloid size, water velocity and fracture width. However, under most of the cases, in contrast to the behavior of a conservative tracer, colloids recovery was much lower than 100 %. Differences in recovery between different nanoparticles, under similar residence times, were analyzed. In order to evaluate the possible consequences, on contaminant migration, of the presence of nanoparticles in the system, transport tests were carried out with both colloids and sorbing radionuclides. The overall capacity for colloids of enhancing radionuclide migration in crystalline rock fractures is discussed. Acknowledgments: The research leading to these results received funding from EU FP7/2007-2011 grant agreement Nº 295487 (BELBAR, Bentonite Erosion: effects on the Long term performance of the engineered Barrier and Radionuclide Transport) and by the Spanish Government under the project NANOBAG (CTM2011-2797).

  14. Migration and Remittances Factbook 2016, Third Edition

    OpenAIRE

    World Bank Group

    2016-01-01

    The Migration and Remittances Factbook 2016 attempts to present numbers and facts behind the stories of international migration and remittances, drawing on authoritative, publicly available data. It provides a snapshot of statistics on immigration, emigration, skilled emigration, and remittance flows for 210 countries and 15 regional and income groups. The Migration and Remittances Factbook 2016 updates the 2011 edition of the Factbook with additional data on bilateral migration and remittanc...

  15. Capitalist development and internal migration in Nigeria.

    Science.gov (United States)

    Akor, R I; Mou, D

    1986-12-01

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

  16. Globalization and formal sector migration in Brazil

    OpenAIRE

    Aguayo-Tellez, Ernesto; Muendler, Marc-Andreas; Poole, Jennifer Pamela

    2008-01-01

    We use novel linked employer–employee data to study the relationship between globalization and formal sector interstate migration for Brazil. We estimate the worker’s multichoice migration problem and document that previously unobserved employer covariates are significant predictors associated with migration flows. Our results provide support for the idea that globalization acts on internal migration through the growth of employment opportunities at locations with a high concentration of fore...

  17. Juridical structures: refugees and migration.

    Science.gov (United States)

    Veiter, T

    1988-01-01

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

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

    Science.gov (United States)

    Cotlear, D

    1984-06-01

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

  19. 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...

  20. Migration Flows: Measurement, Analysis and Modeling

    NARCIS (Netherlands)

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

    2016-01-01

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

  1. Extensions to the coupled chemical equilibria and migration code CHEQMATE

    International Nuclear Information System (INIS)

    Haworth, A.; Sharland, S.M.; Tasker, P.W.; Tweed, C.J.

    1988-08-01

    The CHEQMATE program was developed to model the evolution of spatially inhomogeneous aqueous chemical systems. The original CHEQMATE models one-dimensional diffusion and electromigration of ionic species with chemical equilibration provided by the geochemical program PHREEQE. CHEQMATE has principally been used to study the evolution of the chemical environment in and around a nuclear waste repository. In this paper, we describe extensions to CHEQMATE to increase the range of situations that can be modelled. These extensions are the addition of advection of species in a constant groundwater flow, the facility to model migration of species through a series of media with different transport properties and migration in a spherical geometry which allows investigation of dilution effects. For each extension, we describe the alterations in the transport part of the code and consider how the model is set up. An example of a problem using the different versions is given. (author)

  2. Brine Migration in Heated Salt: Lessons Learned from Field Experiments

    Science.gov (United States)

    Kuhlman, K. L.; Matteo, E. N.; Mills, M.

    2017-12-01

    We summarize several interesting brine migration related phenomena hinted at in field experiments from field testing related to salt radioactive waste repositories in Germany and the US. Past heater tests in salt have shown 1) thermal-hydrological-mechanical coupling is quite strong during both heating and cooling; 2) chemical composition of brine evolves during heating, and comprises a mix of several water sources; and 3) acid gas (HCl) generation has been observed during past heater tests and may have multiple mechanisms for formation. We present a heated brine migration test design, formulated with these complexities in mind. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525.

  3. 'Kozloduy' NPP geological environment as a barrier against radionuclide migration

    International Nuclear Information System (INIS)

    Antonov, D.

    2000-01-01

    The aim of this report is to present an analysis of the geological settings along Kozloduy NPP area from the viewpoint of a natural, protective barrier against unacceptable radionuclides migration in the environment. Possible sources of such migration could be an eventual accident in an active nuclear plant; radioactive releases from decommissioned Power Units or from temporary or permanent radioactive waste repositories. The report is directed mainly to the last case, and especially to the site selection for near surface short lived low and intermediate level (LILW) radioactive repository. The main conclusion of the geological settings assessment and of the many years monitoring is that the Kozloduy NPP area offers good possibilities for site selection of LILW repository. (author)

  4. 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…

  5. Nuclide-migration field experiments

    International Nuclear Information System (INIS)

    Erdal, B.R.; Wolfsberg, K.; Johnstone, J.K.; Erickson, K.L.; Friedman, A.M.; Fried, S.; Hines, J.J.

    1981-03-01

    When considering groundwater flow and radionuclide retention in the complex flow systems that can occur in geologic formations, one has a serious problem in determining if laboratory studies are being performed under conditions appropriate to natural systems. This document is the project plan for a program designed to begin to address these problems. The project is being carried out jointly by the Los Alamos National Laboratory, Sandia National Laboratories, and Argonne National Laboratory. The work has three principal objectives: (1) to develop the experimental, instrumental, and safety techniques necessary to conduct controlled, small-scale radionuclide migration field experiments, including those involving actinides; (2) to use these techniques to define radionuclide migration through rock by performing generic, at-depth experiments under closely monitored conditions; and (3) to determine whether available lithologic, geochemical, and hydrologic properties together with existing or developing transport models are sufficient and appropriate to describe real field conditions

  6. MIGRATION OF ORACLE HR DATABASE

    CERN Multimedia

    ais.support@cern.ch

    2001-01-01

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

  7. Nuclide-migration field experiments

    Energy Technology Data Exchange (ETDEWEB)

    Erdal, B.R.; Wolfsberg, K.; Johnstone, J.K.; Erickson, K.L.; Friedman, A.M.; Fried, S.; Hines, J.J.

    1981-03-01

    When considering groundwater flow and radionuclide retention in the complex flow systems that can occur in geologic formations, one has a serious problem in determining if laboratory studies are being performed under conditions appropriate to natural systems. This document is the project plan for a program designed to begin to address these problems. The project is being carried out jointly by the Los Alamos National Laboratory, Sandia National Laboratories, and Argonne National Laboratory. The work has three principal objectives: (1) to develop the experimental, instrumental, and safety techniques necessary to conduct controlled, small-scale radionuclide migration field experiments, including those involving actinides; (2) to use these techniques to define radionuclide migration through rock by performing generic, at-depth experiments under closely monitored conditions; and (3) to determine whether available lithologic, geochemical, and hydrologic properties together with existing or developing transport models are sufficient and appropriate to describe real field conditions.

  8. Physicists' Forced Migrations under Hitler

    Science.gov (United States)

    Beyerchen, Alan

    2011-03-01

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

  9. Migration from India to Australia.

    Science.gov (United States)

    Awasthi, S P; Chandra, A

    1994-01-01

    "The article examines the contemporary trends and future prospects of migration from India to Australia. The focus is on Indian Settlers and Temporary Entrants admitted to Australia for employment and Indian students admitted to Australia for higher studies. The volume of emigration for permanent residence during the early 1990s has made India one of the leading source countries of migration to Australia. A majority of Indians admitted as Settlers every year join the labor force. Recent data indicate that, among Indian Settlers, there is a preponderance of unsponsored Independent Skilled Migrants. Given the anticipated growth in the number of Indian students, the coming years are likely to witness a spurt in Skilled Temporary Workers from India." excerpt

  10. Migration towards Windows 2000/XP

    International Nuclear Information System (INIS)

    Gal, J.

    2004-01-01

    The article deals with interesting technical solutions used in the project 'Migration towards Windows 2000/XP', which was introduced by the company AITEN, Plc for companies SE Plc, SEPS Plc and TEKO, Plc in the period 2002 and 2003. The contents of the project was migration of about 100 servers and more than 4 000 PC to the Windows 2000 and XP environs. The result of the project is a unified and documented system in the field of file, print and small application servers and PC. It has enabled to increase the system reliability and availability, to decrease the total costs for administration and operation and to establish the steady environs for users of the applications. (author)

  11. Nuclear Medicine

    Science.gov (United States)

    ... Parents/Teachers Resource Links for Students Glossary Nuclear Medicine What is nuclear medicine? What are radioactive tracers? ... funded researchers advancing nuclear medicine? What is nuclear medicine? Nuclear medicine is a medical specialty that uses ...

  12. Tensit - a simulation tool for migration, risk and dose calculations

    International Nuclear Information System (INIS)

    Jones, J.; Kautsky, U.; Vahlund, C.F.

    2004-01-01

    During the next years the Swedish Nuclear Fuel and Waste Management Co (SKB) performs site investigations for a future repository of spent nuclear fuel. The repository will be situated in crystalline rock at a depth of approximately 500 m. Novel methods based on systems and landscape ecology are developed to understand the interacting mechanisms and finally, to model radionuclide migration in the biosphere using site specific data. These models and methods are later used as part of the overall safety assessment for the repository where also migration in the near field and in the bedrock is considered. In the present paper, a newly developed probabilistic simulation package, TENSIT, is presented. The package is based on pre-existing codes (Matlab, Simulink and the probabilistic engine-at-risk) and is capable of performing radionuclide migration calculations both for the repository and the biosphere. Hence, a platform independent, transparent (well documented and intuitive on a model scale), thoroughly supported, efficient and user friendly (graphical interface for the modeler) code can be developed at a fairly low cost. Comparisons with other codes used for compartment based biosphere modelling and the PSACOIN Level 1B exercise shows on a good agreement on the application scale. Moreover, by basing the package on continuously maintained, pre-existing codes, potential risks associated with a less spread software may be avoided. In addition to the compartment based models based on transfer factors, TENSIT is also able to handle the more complex ecosystem models (based on flow of carbon and nutrients) either separately or in combination with the compartment models. Within the project, biosphere migration calculations have been performed using TENSIT for a watershed in the Forsmark area (one of the studied sites). In this simulation, data from the ongoing site investigation program has been used to define the based model. (author)

  13. Incentives and disincentives: international migration.

    Science.gov (United States)

    Bhagwati, J N

    1984-01-01

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

  14. Nuclear safety. Seguranca nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Aveline, A [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica

    1981-01-01

    What is nuclear safety Is there any technical way to reduce risks Is it possible to put them at reasonable levels Are there competitiveness and economic reliability to employ the nuclear energy by means of safety technics Looking for answers to these questions the author describes the sources of potential risks to nuclear reactors and tries to apply the answers to the Brazilian Nuclear Programme. (author).

  15. ILLEGAL MIGRATION-CONCEPTUAL DELIMITATIONS

    Directory of Open Access Journals (Sweden)

    CRISTINA FLORINA POPESCU (PANAIT

    2013-05-01

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

  16. Radionuclide migration studies at the Nevada Test Site

    International Nuclear Information System (INIS)

    Thompson, J.L.

    1989-01-01

    The United States government routinely tests nuclear devices at the Nevada Test Site (NTS) in southern Nevada. A significant amount of radioactive material exists underground at the NTS with no containers or engineered barriers to inhibit its subsequent migration. The Department of Energy has sponsored for many years a research program on radionuclide movement in the geologic media at this location. Goals of this research program are to measure the extent of movement of radionuclides away from underground explosion sites and to determine the mechanisms by which such movement occurs. This program has acquired significance in another aspect of nuclear waste management because of the Yucca Mountain Project. Yucca Mountain at the NTS is being intensively studied as the possible site for a mined repository for high level nuclear waste. The NTS provides a unique setting for field studies concerning radionuclide migration; there is the potential for greatly increasing our knowledge of the behavior of radioactive materials in volcanogenic media. This review summarizes some of the significant findings made under this research program at the NTS and identifies reports in which the details of the research may be found. 36 refs., 4 figs

  17. Water and contaminant movement: migration barriers

    International Nuclear Information System (INIS)

    Lane, L.J.; Nyhan, J.W.

    1984-11-01

    Migration barriers are used in shallow land burial facilities to slow or stop the movement of water and contaminants and are discussed here as a single component embedded in a complex environmental system. Analytical solutions to solute transport equations are used to approximate the behavior of migration barriers and to derive design criteria for control of subsurface water and contaminant migration. Various types of migration barriers are compared and design recommendations are made for shallow land burial trench caps and liners. Needed improvements and suggested field experiments for future designs of migration barriers are then discussed relative to the management of low-level radioactive wastes

  18. National and international graduate migration flows.

    Science.gov (United States)

    Mosca, Irene; Wright, Robert E

    2010-01-01

    This article examines the nature of national and international graduate migration flows in the UK. Migration equations are estimated with microdata from a matched dataset of Students and Destinations of Leavers from Higher Education, information collected by the Higher Education Statistical Agency. The probability of migrating is related to a set of observable characteristics using multinomial logit regression. The analysis suggests that migration is a selective process with graduates with certain characteristics having considerably higher probabilities of migrating, both to other regions of the UK and abroad.

  19. Family migration and relative earnings potentials

    DEFF Research Database (Denmark)

    Foged, Mette

    2016-01-01

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

  20. 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.

  1. 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.

  2. Invisible nuclear; converting nuclear

    International Nuclear Information System (INIS)

    Park, Jongmoon

    1993-03-01

    This book consists of 14 chapters which are CNN era and big science, from East and West to North and South, illusory nuclear strategy, UN and nuclear arms reduction, management of armaments, advent of petroleum period, the track of nuclear power generation, view of energy, internationalization of environment, the war over water in the Middle East, influence of radiation and an isotope technology transfer and transfer armament into civilian industry, the end of nuclear period and the nuclear Nonproliferation, national scientific and technological power and political organ and executive organ.

  3. Radionuclide migration in soil within the estrangement zone of ChNPP

    International Nuclear Information System (INIS)

    Mikhalkin, G.S.; Arkhipov, A.N.; Arkhipov, N.P.; Sukhoruchkin, A.K.

    1992-01-01

    The problems of the radionuclide migration and redistribution in soil within the estrangement zone of ChNPP have been discussed. It has been demonstrated that the surface radioactive contamination of soil that has been represented principally by the particles of the waste nuclear fuel eventually migrates into soil depth. In this case the radionuclides remain principally the fuel matrix components, the fuel matrix decomposing gradually and releasing the radionuclides. The mechanisms of the radionuclide migration can be described with the quasi-diffusion migration model in most cases. On the 5th year since the accident the major portion of the radionuclides (95-99%) is still kept within 0-5 cm layer of soil. 3 figs.; 7 tabs

  4. Delphinidin inhibits BDNF-induced migration and invasion in SKOV3 ovarian cancer cells.

    Science.gov (United States)

    Lim, Won-Chul; Kim, Hyunhee; Kim, Young-Joo; Park, Seung-Ho; Song, Ji-Hye; Lee, Ki Heon; Lee, In Ho; Lee, Yoo-Kyung; So, Kyeong A; Choi, Kyung-Chul; Ko, Hyeonseok

    2017-12-01

    Brain-derived neurotrophic factor (BDNF), the TrkB ligand, is associated with aggressive malignant behavior, including migration and invasion, in tumor cells and a poor prognosis in patients with various types of cancer. Delphinidin is a diphenylpropane-based polyphenolic ring structure-harboring compound, which exhibits a wide range of pharmacological activities, anti-tumor, anti-oxidant, anti-inflammatory, anti-angiogenic and anti-mutagenic activity. However, the possible role of delphinidin in the cancer migration and invasion is unclear. We investigated the suppressive effect of delphinidin on the cancer migration and invasion. Thus, we found that BDNF enhanced cancer migration and invasion in SKOV3 ovarian cancer cell. To exam the inhibitory role of delphinidin in SKOV3 ovarian cancer migration and invasion, we investigated the use of delphinidin as inhibitors of BDNF-induced motility and invasiveness in SKOV3 ovarian cancer cells in vitro. Here, we found that delphinidin prominently inhibited the BDNF-induced increase in cell migration and invasion of SKOV3 ovarian cancer cells. Furthermore, delphinidin remarkably inhibited BDNF-stimulated expression of MMP-2 and MMP-9. Also, delphinidin antagonized the phosphorylation of Akt and nuclear translocation of NF-κB permitted by the BDNF in SKOV3 ovarian cancer cells. Taken together, our findings provide new evidence that delphinidin suppressed the BDNF-induced ovarian cancer migration and invasion through decreasing of Akt activation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Nopal I uranium deposit: A study of radionuclide migration

    International Nuclear Information System (INIS)

    Wong, V.; Anthony, E.; Goodell, P.

    1996-01-01

    This summary reports on activities of naturally-occurring radionuclides for the Nopal I uranium deposit located in the Pena Blanca Uranium District, Chihuahua, Mexico. Activities were determined using gamma-ray spectroscopy. In addition, data reduction procedures and sample preparation (for Rn retention) will be discussed here. Nopal I uranium deposit has been identified as one of the most promising sites for analogue studies to the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. The objective of this research is to study the potential for radionuclide migration by testing whether any portion of the deposit is in secular equilibrium

  6. Nopal I uranium deposit: A study of radionuclide migration

    Energy Technology Data Exchange (ETDEWEB)

    Wong, V.; Anthony, E.; Goodell, P. [Univ. of Texas, El Paso, TX (United States)

    1996-12-01

    This summary reports on activities of naturally-occurring radionuclides for the Nopal I uranium deposit located in the Pena Blanca Uranium District, Chihuahua, Mexico. Activities were determined using gamma-ray spectroscopy. In addition, data reduction procedures and sample preparation (for Rn retention) will be discussed here. Nopal I uranium deposit has been identified as one of the most promising sites for analogue studies to the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. The objective of this research is to study the potential for radionuclide migration by testing whether any portion of the deposit is in secular equilibrium.

  7. Nuclear waste - the unsolved problem

    International Nuclear Information System (INIS)

    Boyle, S.

    1986-01-01

    Nuclear waste is identified and the problems created by reprocessing are mentioned. The disposal option for low, intermediate and high-level radioactive wastes are discussed. Sites where disposal has taken place have been found to be unsatisfactory because of contamination and radionuclide migration. The Nuclear Industry Radioactive Waste Executive (NIREX) is not seen as having any more credibility than the other nuclear authorities involved (BNFL, UKAEA, CEGB). Until an adequate, publically acceptable, method of disposing of the wastes already created has been found the author states that no more should be created. (U.K.)

  8. Nuclear pore complex tethers to the cytoskeleton.

    Science.gov (United States)

    Goldberg, Martin W

    2017-08-01

    The nuclear envelope is tethered to the cytoskeleton. The best known attachments of all elements of the cytoskeleton are via the so-called LINC complex. However, the nuclear pore complexes, which mediate the transport of soluble and membrane bound molecules, are also linked to the microtubule network, primarily via motor proteins (dynein and kinesins) which are linked, most importantly, to the cytoplasmic filament protein of the nuclear pore complex, Nup358, by the adaptor BicD2. The evidence for such linkages and possible roles in nuclear migration, cell cycle control, nuclear transport and cell architecture are discussed. Copyright © 2017. Published by Elsevier Ltd.

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

    NARCIS (Netherlands)

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

    2015-01-01

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

  10. Philippine migration policy: dilemmas of a crisis.

    Science.gov (United States)

    Battistella, G

    1999-04-01

    Philippine migration policy is traced from the early 1970s to the present. The main migration trends in the 1990s are described. An assessment is made of the efficacy and appropriateness of present migration policy in light of the economic crisis. A regional approach to migration policy is necessary in order to encourage placing migration as a greater priority on national agendas and in bilateral agreements. In the Philippines, migrants are considered better paid workers, which diminishes their importance as a legislative or program priority. Santo Tomas (1998) conducted an empirical assessment of migration policies in the Philippines, but refinement is needed. Although migration is a transnational experience, there is little dialogue and cooperation among countries. Philippine migration policy defines its role as an information resource for migrants. Policy shifted from labor export to migrant management in the public and private sectors. Predeparture information program studies are recommending a multi-stage process that would involve all appropriate parties. There is talk of including migration information in the education curriculum. There are a variety of agendas, competing interests, and information resources between migration networks and officiating agencies. The Asian financial crisis may have a mild impact, but there are still issues of reintegration, protection, and employment conditions

  11. Asian student migration to Australia.

    Science.gov (United States)

    Shu, J; Hawthorne, L

    1996-01-01

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

  12. 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

  13. Migrating Applications to IPv6

    CERN Document Server

    York, Dan

    2011-01-01

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

  14. Radionuclide migration in geological formations

    International Nuclear Information System (INIS)

    Barbreau, A.; Heremans, R.; Skytte Jensen, B.

    1980-01-01

    Radioactive waste disposal into geological formation is based on the capacity of rocks to confine radioactivity for a long period of time. Radionuclide migration from the repository to the environment depends on different mechanisms and phenomena whose two main ones are groundwater flow and the retention and ion-exchange property of rocks. Many studies are underway presently in EEC countries concerning hydrodynamic characteristics of deep geological formations as well as in radionuclide retention capacity and modelling. Important results have already been achieved which show the complexity of some phenomena and further studies shall principally be developed taking into account real conditions of the repository and its environment

  15. Migration of cesium-137 through sandy soil layer effect of fine silt on migration

    International Nuclear Information System (INIS)

    Ohnuki, Toshihiko; Wadachi, Yoshiki

    1983-01-01

    The migration of 137 Cs through sandy soil layer was studied with consideration of the migration of fine silt by column method. It was found that a portion of fine silt migrated through the soil layer accompanying with 137 Cs. The mathematical migration model of 137 Cs involved the migration of fine silt through such soil layer was presented. This model gave a good accordance between calculated concentration distribution curve in sandy soil layer and effluent curve and observed those. So, this model seems to be advanced one for evaluating migration of 137 Cs in sandy soil layer with silt. (author)

  16. 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.

  17. Large block migration experiments: INTRAVAL phase 1, Test Case 9

    Energy Technology Data Exchange (ETDEWEB)

    Gureghian, A.B.; Noronha, C.J. (Battelle, Willowbrook, IL (USA). Office of Waste Technology Development); Vandergraaf, T.T. (Atomic Energy of Canada Ltd., Ottawa, ON (Canada))

    1990-08-01

    The development of INTRAVAL Test Case 9, as presented in this report, was made possible by a past subsidiary agreement to the bilateral cooperative agreement between the US Department of Energy (DOE) and Atomic Energy of Canada Limited (AECL) encompassing various aspects of nuclear waste disposal research. The experimental aspect of this test case, which included a series of laboratory experiments designed to quantify the migration of tracers in a single, natural fracture, was undertaken by AECL. The numerical simulation of the results of these experiments was performed by the Battelle Office of Waste Technology Development (OWTD) by calibrating an in-house analytical code, FRACFLO, which is capable of predicting radionuclide transport in an idealized fractured rock. Three tracer migration experiments were performed, using nonsorbing uranine dye for two of them and sorbing Cs-137 for the third. In addition, separate batch experiments were performed to determine the fracture surface and rock matrix sorption coefficients for Cs-137. The two uranine tracer migration experiment were used to calculate the average fracture aperture and to calibrate the model for the fracture dispersivity and matrix diffusion coefficient. The predictive capability of the model was then tested by simulating the third, Cs-137, tracer test without changing the parameter values determined from the other experiments. Breakthrough curves of both the experimental and numerical results obtained at the outlet face of the fracture are presented for each experiment. The reported spatial concentration profiles for the rock matrix are based solely on numerical predictions. 22 refs., 12 figs., 8 tabs.

  18. 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.

  19. Colloid migration in porous media

    International Nuclear Information System (INIS)

    Hunt, J.R.; McDowell-Boyer; Sitar, N.

    1985-01-01

    Retention of radionuclides for long periods near waste repositories depends upon multiple barriers, one of which is adsorption to immobile solid surfaces. Since small particles and colloidal matter have high adsorption capacities per unit mass and can be mobile in subsurface flows, colloidal transport of waste components requires analysis. Theories for predicting colloid migration through porous media have been developed in the filtration literature. The applicability of filtration theories for predicting particle and colloid transport. Emphasis is on suspended matter much smaller than pore sizes, where physical and chemical forces control migration rather than size dependent physical straining. In general, experimentally verifiable theories exist for particle filtration by clean media, and a sensitivity analysis is possible on particle and media properties and fluid flow rate. When particle aggregates accumulate within pores, media permeability decreases, resulting in flow field alteration and possible radionuclide isolation. An analysis of the limited experimental data available indicates that present theories cannot predict long-term colloid transport when permeability reduction occurs. The coupling of colloid attachment processes and the hydrologic flow processes requires more extensive laboratory field research than has currently been carried out. An emphasis on the fundamental mechanisms is necessary to enhance long-term predictability

  20. Modelling collective cell migration of neural crest.

    Science.gov (United States)

    Szabó, András; Mayor, Roberto

    2016-10-01

    Collective cell migration has emerged in the recent decade as an important phenomenon in cell and developmental biology and can be defined as the coordinated and cooperative movement of groups of cells. Most studies concentrate on tightly connected epithelial tissues, even though collective migration does not require a constant physical contact. Movement of mesenchymal cells is more independent, making their emergent collective behaviour less intuitive and therefore lending importance to computational modelling. Here we focus on such modelling efforts that aim to understand the collective migration of neural crest cells, a mesenchymal embryonic population that migrates large distances as a group during early vertebrate development. By comparing different models of neural crest migration, we emphasize the similarity and complementary nature of these approaches and suggest a future direction for the field. The principles derived from neural crest modelling could aid understanding the collective migration of other mesenchymal cell types. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. 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

  2. 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)

  3. Migration in Asia-Europe Relations

    DEFF Research Database (Denmark)

    Juego, Bonn

    2010-01-01

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

  4. Political motivations for intra-European migration.

    Science.gov (United States)

    Bygnes, Susanne; Flipo, Aurore

    2017-08-01

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

  5. 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.

  6. A study on the radiometric method for evaluating element migration from plastic packagings to its contents

    International Nuclear Information System (INIS)

    Soares, Eufemia Paez

    2008-01-01

    Over the past few years, problems related to food contamination by substances or elements that can be a risk to human health have became a concern, not only to government authorities, but to the general population as well. Within this context, plastic packaging can constitute a source of food contamination since plastic manufacturing processes involve the use of catalysts and different types of additives that may contain toxic elements. When food comes into contact with this packaging, components of the package may migrate to the food. In order to control the material used as food packaging, the National Health Surveillance Agency (ANVISA) in Brazil, has established boundary values of migrant substances and procedures to determine migration from plastic packagings to food. In this study the radiometric method was evaluated for element migration determination from plastic packaging to food simulating or to the food itself. This radiometric method consisted in irradiating plastic packaging samples with a thermal neutron flux from the IEA-R1 nuclear research reactor in order to produce radionuclides of elements present in the packagings. The irradiated plastic was then exposed to food simulant or food for element migration. Gamma ray spectrometry was used to measure radioactivity in the simulant or food in order to quantify the migration. The food simulating types and experimental conditions were established according to the ANVISA regulations. Element migration was studied for plastic packaging used for soft drinks, drinking water, milk, dairy products, juices and fatty foods. In the instrumental neutron activation analysis of these packagings the presence of As, Cd, Cr, Co and Sb II was verified. Results obtained from the migration experiments by the radiometric method indicated that Cd, Co, Cr and Sb present in these plastics migrated to the simulant or to the food. In some packagings, the migration of only some of these elements was observed. In these cases the

  7. 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

  8. [Nuclear theory

    International Nuclear Information System (INIS)

    Haxton, W.

    1990-01-01

    This report discusses research in nuclear physics. Topics covered in this paper are: symmetry principles; nuclear astrophysics; nuclear structure; quark-gluon plasma; quantum chromodynamics; symmetry breaking; nuclear deformation; and cold fusion

  9. 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.)

  10. Elastic least-squares reverse time migration

    KAUST Repository

    Feng, Zongcai; Schuster, Gerard T.

    2016-01-01

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

  11. Cesium migration in LMFBR fuel pins

    International Nuclear Information System (INIS)

    Karnesky, R.A.; Jost, J.W.; Stone, I.Z.

    1978-10-01

    The factors affecting the axial migration of cesium in mixed oxide fuel pins and the effects of cesium migration on fuel pin performance are examined. The development and application of a correlated model which will predict the occurrence of cesium migration in a mixed oxide (75 w/o UO 2 + 25 w/o PuO 2 ) fuel pins over a wide range of fabrication and irradiation conditions are described

  12. The mechanism for migration in Poland.

    Science.gov (United States)

    Rykiel, Z

    1988-01-01

    The author reviews neoclassical theories and models of migration. The mobility theory, which concerns the impact of local labor markets on migration, is discussed in the Polish context. A general model of the regional labor market and a multicausal model are developed to explain the patterns of internal migration. The period of a managed economy (1949-1980) is contrasted with the period since the implementation of a new economic system in 1983.

  13. Internal migration and income of immigrant families

    OpenAIRE

    Rashid, Saman

    2004-01-01

    Using a longitudinal dataset from the years 1995 and 2000, respectively, this study examines whether migration within the host country of Sweden generates higher total annual income for (two-earner) immigrant families. The empirical findings indicate that internal migration generates a positive outcome in terms of higher family income for newly arrived refugee-immigrant families. Further, with the length of residence in the host country, the monetary gain accruing from internal migration decr...

  14. 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...

  15. 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.

  16. Elastic least-squares reverse time migration

    KAUST Repository

    Feng, Zongcai

    2016-09-06

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

  17. Navigational Strategies of Migrating Monarch Butterflies

    Science.gov (United States)

    2014-11-10

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

  18. 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...

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

    Directory of Open Access Journals (Sweden)

    D. Chigudu

    2015-12-01

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

  20. 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

  1. [Migration mobility and movement of the population].

    Science.gov (United States)

    Zaslavska, T; Ribakovski, L

    1983-01-01

    "The functions of migration are reviewed from the viewpoint of the demographic situation in the USSR (by regions, sex, age, education, profession, labour and social activity, nationality, rural-urban, etc.). Some effects of migration on fertility are shown. The authors investigate the role of the economic functions of migration for the process of professional mobility. The territorial mobility of the population is analysed on a wider scale as a part of the social mobility in the socialist society. In connection with this, some problems of the migration policy as an element of the demographic policy of the USSR are outlined." (summary in ENG, RUS) excerpt

  2. Nuss bar migrations: occurrence and classification

    International Nuclear Information System (INIS)

    Binkovitz, Lauren E.; Binkovitz, Larry A.; Zendejas, Benjamin; Moir, Christopher R.

    2016-01-01

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

  3. The migration of uranium through sandstone

    International Nuclear Information System (INIS)

    Bennett, D.G.; Read, D.; Lawless, T.A.; Sims, R.J.

    1992-01-01

    Three column experiments are described in which the migration of uranium through Clashach Sandstone was studied. A priori predictions of uranium migration in the experiments were made using an equilibrium chemical transport model. The experimental results showed that, even under oxidising conditions, the migration of uranium is strongly retarded owing to the affinity of uranium for mineral surfaces. For the relatively simple chemical system investigated, the chemical transport model was successful in predicting the migration of uranium and its distribution along the column. (author)

  4. Migration processes in SCO member states

    Directory of Open Access Journals (Sweden)

    Valentina Sergeevna Antonyuk

    2012-12-01

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

  5. Motorized Migrations: the Future or Mere Fantasy?

    Science.gov (United States)

    Ellis, D.H.; Sladen, William J. L.; Lishman, W.A.; Clegg, K.R.; Duff, J.W.; Gee, G.F.; Lewis, J.C.

    2003-01-01

    In 15 experiments from 1993-2002, we led cranes, geese, or swans on their first southward migration with either ultralight aircraft or vehicles on the ground. These experiments reveal that large birds can be readily trained to follow and most will return north (and south) in subsequent migrations unassisted. These techniques can now be used to teach birds new (or forgotten) migration paths. Although we are constantly improving our training techniques, we now have an operational program that can be broadly applied to those species where juveniles learn migration routes from their parents.

  6. Nuss bar migrations: occurrence and classification

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-15

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

  7. 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.

  8. Nuclear topics

    International Nuclear Information System (INIS)

    Lukner, C.

    1982-07-01

    The pamphlet touches on all aspects of nuclear energy, from the world energy demands and consumption, the energy program of the Federal Government, nuclear power plants in the world, nuclear fusion, nuclear liability up to the nuclear fuel cycle and the shutdown of nuclear power plants. (HSCH) [de

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

    Science.gov (United States)

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

    2016-01-01

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

  10. An investigation of tendon sheathing filler migration into concrete

    International Nuclear Information System (INIS)

    Naus, D.J.; Oland, C.B.

    1998-03-01

    During some of the inspections at nuclear power plants with prestressed concrete containments, it was observed that the containments has experienced leakage of the tendon sheathing filler (i.e., streaks). The objective of this activity was to provide an indication of the extent of tendon sheathing filler leakage into the concrete and its affects on concrete properties. Literature was reviewed and concrete core samples were obtained from the Trojan Nuclear Plant and tested. The literature primarily addressed effects of crude or lubricating oils that are known to cause concrete damage. However, these materials have significantly different characteristics relative to the materials used as tendon sheathing fillers. Examination and testing of the concrete cores indicated that the appearance of tendon sheathing filler on the concrete surface was due to leakage from the conduits and its subsequent migration through cracks that were present. Migration of the tendon sheathing filler was confined to the cracks and there was no perceptible movement into the concrete. Results of compressive strength testing indicated that the concrete quality was consistent in the containment and that the strength had increased over 40% in 25.4 years relative to the average compressive strength at 28-days age

  11. Brine migration test - Asse salt mine, Federal Republic of Germany

    International Nuclear Information System (INIS)

    Rothfuchs, T.; Wieczorek, K.; Feddersen, H.K.; Staupendahl, G.; Coyle, A.J.; Kalia, H.; Eckert, J.

    1988-03-01

    This document is the final report on the Cooperative German-American 'Brine Migration Tests' that were performed at the Asse Salt Mine in the Federal Republic of Germany (FRG), the Office of Nuclear Waste Isolation (ONWI), Columbus, Ohio, and the Institut fuer Tieflagerung (IfT), Braunschweig, of the Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen (GSF). Final test and equipment design as well as manufacturing and installation was carried out by Westinghouse Electric Corporation. The tests were designed to simulate a nuclear waste repository to measure the effects of heat and gamma radiation on brine migration, salt decrepitation, disassociation of brine, and gases collected. The thermal mechanical behavior of salt, such as room closure, stresses and changes of the properties of salt are measured and compared with predicted behavior. The performance of an array of candidate waste package materials, test equipment and procedures under repository conditions will be evaluated with a view towards future in-depth testing of potential repository sites. (orig./RB)

  12. Migration studies of fission product nuclides in rocks. Pt.5: Diffusion and permeability of nuclide 125I in marble

    International Nuclear Information System (INIS)

    Wen Ruiyuan; Gao Hongcheng; Wang Xiangyun

    1996-01-01

    The migration behaviour of nuclide 125 I, as a simulation of the long lived fission product 129 I, in marble is studied in self-designed cells. A series of the most important parameters of diffusion and permeability (e.g., intrinsic diffusion coefficient, dispersion coefficient and interstitial flow velocity, etc.) are determined. Based on the differential equation of the nuclide migration, the distribution function and numerical solution of 125 I in marble are presented. The results show that the migration velocity of 125 I in marble is fast, indicating that it is not suitable to dispose nuclear waste in marble

  13. Family characteristics of internal migration in China.

    Science.gov (United States)

    Rowland, D T

    1992-03-01

    Data from the 1986 survey of migration conducted by the Chinese Academy of Social Sciences (CASS) were used to examine family characteristics of internal migrants to urban areas in China. The influence of the family either directly or indirectly is considered as part of life cycle events. .2% of households in 74 cities and towns were surveyed (100,267 persons). Data were analyzed 1) for persons who moved within 10 years of the survey (47%--17,890 out of 38,104 in-migrants), and 2) by last move by age regardless of when (72% between 1966-86). The literature and conditions in China strongly support that family welfare is likely to be a significant underlying influence on patterns and selectivity of migration in China. The CASS survey reveals that the most movers were from nuclear families aged 25-44 years, followed by stem families (a couple plus 1 or more parents). 6 factors are identified for sustaining co-residence within generations. Migrations during 1977-86 showed that 41% of males aged 20-24 years had moved at least once (18% were married), while for females the figure was 25% (50% were married). 56% of males moving at ages 25-29 years were married, and 90% of migrant males aged 30-34 years were married. 78% of married females aged 25-29 years and 94% of those aged 30-34 years moved. 23% of widowed females aged 50-54 years were in-migrants, and 69% were aged 65 years and widowed. The opportunity for 2- and 3- generation households is expected t decline over the next 50 years as the population ages and becomes larger than the supporting population. 44% of young-old women (75-74 years) with no children and 25-33% of young-old women total had moved within the last 10 years. 43% of women aged 75 years or older with 5 or more children moved within 10 years, while only 24% with no children had. Women aged 35-54 years had low rates of movement with high parity, while those aged 25-44 with 1 or no children had higher rates of movement. Parity is increasingly

  14. Nuclear power and nuclear weapons

    International Nuclear Information System (INIS)

    Vaughen, V.C.A.

    1983-01-01

    The proliferation of nuclear weapons and the expanded use of nuclear energy for the production of electricity and other peaceful uses are compared. The difference in technologies associated with nuclear weapons and nuclear power plants are described

  15. Verification and improvement of predictive algorithms for radionuclide migration

    International Nuclear Information System (INIS)

    Carnahan, C.L.; Miller, C.W.; Remer, J.S.

    1984-01-01

    This research addresses issues relevant to numerical simulation and prediction of migration of radionuclides in the environment of nuclear waste repositories. Specific issues investigated are the adequacy of current numerical codes in simulating geochemical interactions affecting radionuclide migration, the level of complexity required in chemical algorithms of transport models, and the validity of the constant-k/sub D/ concept in chemical transport modeling. An initial survey of the literature led to the conclusion that existing numerical codes did not encompass the full range of chemical and physical phenomena influential in radionuclide migration. Studies of chemical algorithms have been conducted within the framework of a one-dimensional numerical code that simulates the transport of chemically reacting solutes in a saturated porous medium. The code treats transport by dispersion/diffusion and advection, and equilibrium-controlled proceses of interphase mass transfer, complexation in the aqueous phase, pH variation, and precipitation/dissolution of secondary solids. Irreversible, time-dependent dissolution of solid phases during transport can be treated. Mass action, transport, and sorptive site constraint equations are expressed in differential/algebraic form and are solved simultaneously. Simulations using the code show that use of the constant-k/sub D/ concept can produce unreliable results in geochemical transport modeling. Applications to a field test and laboratory analogs of a nuclear waste repository indicate that a thermodynamically based simulator of chemical transport can successfully mimic real processes provided that operative chemical mechanisms and associated data have been correctly identified and measured, and have been incorporated in the simulator. 17 references, 10 figures

  16. Pressure-driven brine migration in a salt repository

    International Nuclear Information System (INIS)

    Hwang, Y.; Chambre, P.L.; Pigford, T.H.; Lee, W.W.L.

    1989-01-01

    The traditional view is that salt is the ideal rock for isolation of nuclear waste because it is ''dry'' and probably ''impermeable.'' The existence of salt through geologic time is prima facie evidence of such properties. Experiments and experience at potential salt sites for geologic repositories have indicated that while porosity and permeability of salt are low, the salt may be saturated with brine. If this hypothesis is correct, then it is possible to have brine flow due to pressure differences within the salt. If there is pressure-driven brine migration in salt repositories then it is paramount to know the magnitude of such flow because inward brine flow would affect the corrosion rate of nuclear waste containers and outward brine flow might affect radionuclide transport rates. Brine exists in natural salt as inclusions in salt crystals and in grain boundaries. Brine inclusions in crystals move to nearby grain boundaries when subjected to a temperature gradient, because of temperature-dependent solubility of salt. Brine in grain boundaries moves under the influence of a pressure gradient. When salt is mined to create a waste repository, brine from grain boundaries will migrate into the rooms, tunnels and boreholes because these cavities are at atmospheric pressure. After a heat-emitting waste package is emplaced and backfilled, the heat will impose a temperature gradient in the surrounding salt that will cause inclusions in the nearby salt to migrate to grain boundaries within a few years, adding to the brine that was already present in the grain boundaries. The formulation of brine movement with salt as a thermoelastic porous medium, in the context of the continuum theory of mixtures, has been described. In this report we show the mathematical details and discuss the results predicted by this analysis

  17. Parameters Affecting 137Cs Migration within Soil Profile

    International Nuclear Information System (INIS)

    Sefien, S.M.; Ibrahim, A.S.; Abdelmalik, W.E.Y.

    2013-01-01

    Some studies have been carried out on the adsorption, distribution and migration of 137 Cs within soils of the area in the vicinity of the Nuclear Research Centre, Egypt, and Ismailia Canal. The soil physicochemical and mineralogical characteristics were carried out and indicated that the soil samples consisted mainly of sand fraction (quartz) and silt fractions (semctite minerals). The kinetics of caesium adsorption and its adsorption isotherms for the tested soils were also studied. The sorption of 137 Cs on soil minerals markedly affects its migration rate. The natural background of both locations of study indicated that the amounts of 137 Cs present in the reactor site were found to be originated from the fallout and from the external contamination which affected the background level. The 137 Cs activity at the canal site was found to be 20.01 Bq/m 2 .cm, while that around the reactor site were found to be 231.15 Bq/m2.cm which may be originating from the fallout and from external contamination which affect the background level at that location. The activity in the canal soil which amounted to 20.01 Bq/m2/cm (0.87 Bq/kg) is about that of background.Based on the distribution data, the vertical distribution of 137 Cs has been studied for soil in both locations (the vicinity of the Nuclear Research Centre (NRC) and Ismailia canal). The vertical migration rates of 137 Cs were calculated for soil samples selected from different locations. These rates were found to be 0.056 and 0.031 cm/year for the reactor and canal site respectively.

  18. Migrations of theory, method and practice: a reflection on themes in migration studies (Review article)

    OpenAIRE

    Palmary, Ingrid

    2009-01-01

    In this review article, I offer some reflection on three themes in migration research, namely, the categorisation and quantification of migration, the role of trauma and distress in such categorisation, and the feminisation of migration. I was prompted to explore these three themes after reading a recent publication on migration in southern Africa (edited by Kok, Gelderblom, Oucho and Van Zyl, 2006). In this paper I raise these as three areas that appear to be determining the boundaries of th...

  19. 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...

  20. 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.

  1. Nuclear smuggling in Europe real dangers and enigmatic deceptions

    International Nuclear Information System (INIS)

    Schaper, A.

    1998-01-01

    During the last years, alarming news has accumulated on smuggled nuclear material, migrating experts, stolen bombs and new miracle substances that render obsolete all nonproliferation efforts. Together with a look at the economic difficulties, sinking living standards, and rising unemployment in the CIS countries, a pessimistic impression evolves of how to control the huge Russian nuclear complex and how to stem further proliferation of nuclear weapons. This paper tries to assess the dangers of nuclear smuggling and to discuss some possibilities for remedies

  2. Morphological constraints on changing avian migration phenology.

    Science.gov (United States)

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

    2017-06-01

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

  3. 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.

  4. 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.

  5. Void migration in fusion materials

    International Nuclear Information System (INIS)

    Cottrell, G.A.

    2002-01-01

    Neutron irradiation in a fusion power plant will cause helium bubbles and voids to form in the armour and blanket structural materials. If sufficiently large densities of such defects accumulate on the grain boundaries of the materials, the strength and the lifetimes of the metals will be reduced by helium embrittlement and grain boundary failure. This Letter discusses void migration in metals, both by random Brownian motion and by biassed flow in temperature gradients. In the assumed five-year blanket replacement time of a fusion power plant, approximate calculations show that the metals most resilient to failure are tungsten and molybdenum, and marginally vanadium. Helium embrittlement and grain boundary failure is expected to be more severe in steel and beryllium

  6. Colloid migration in fractured media

    International Nuclear Information System (INIS)

    Hunt, J.R.

    1989-01-01

    Field studies at the Nevada Test Site by researchers at Lawrence Livermore National Laboratory have demonstrated that radionuclides are being transported by colloidal material suspended in groundwater. This observation is counter to most predictions from contaminant transport models because the models assume adsorbed species are immobile. The purpose of this research is to quantify the transport processes for colloidal materials and develop the mechanistic understanding necessary to predict radionuclide transport in fractured media. There were three areas of investigation during this year that have addressed these issues: chemical control of colloid deposition on clean mineral surfaces, colloid accumulation on fracture surfaces, and the influence of deposited colloids on colloid and tracer migration. 7 refs

  7. Seismic migration in generalized coordinates

    Science.gov (United States)

    Arias, C.; Duque, L. F.

    2017-06-01

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

  8. [Migration and oil in Tabasco].

    Science.gov (United States)

    Lezama, J L

    1987-01-01

    "At the beginning of the seventies, important economic investments aimed at developing and commercializing the newly discovered oilwells were made in the state of Tabasco [Mexico]. As a result of this, the distribution and the social growth of the population in this state changed. This paper analyses the general characteristics of these changes, particularly those related to migration.... Generally speaking, the most important migratory movements which took place in this state during the oil boom were from one municipality to another and not from other states to Tabasco, as was thought at first.... This paper also describes the direction of the migratory flows and provides information about the sex of the migrants and about their insertion within the sphere of employment." (SUMMARY IN ENG) excerpt

  9. Void migration in fusion materials

    Science.gov (United States)

    Cottrell, G. A.

    2002-04-01

    Neutron irradiation in a fusion power plant will cause helium bubbles and voids to form in the armour and blanket structural materials. If sufficiently large densities of such defects accumulate on the grain boundaries of the materials, the strength and the lifetimes of the metals will be reduced by helium embrittlement and grain boundary failure. This Letter discusses void migration in metals, both by random Brownian motion and by biassed flow in temperature gradients. In the assumed five-year blanket replacement time of a fusion power plant, approximate calculations show that the metals most resilient to failure are tungsten and molybdenum, and marginally vanadium. Helium embrittlement and grain boundary failure is expected to be more severe in steel and beryllium.

  10. Cultural values and international migration

    Directory of Open Access Journals (Sweden)

    Miryam Rodríguez Monter

    2009-05-01

    Full Text Available Immigration is one of the most controversial social issues debated nowadays. It is an undeniable fact that the phenomenon is lived in Europe with concern because of its consequences. People who live and coexist in Europe represent a huge cultural variety. Therefore, social and cultural gaps that can affect the basic values of the western societies seem to be inevitable due to the dimensions of the current migration phenomenon. The present studies are based on the European Social Survey Questionnaire (2002, and the Portrait Values Questionnaire (Schwartz, 1992, 2001 and focuses on the relevance of cultural values to explain the acceptance or rejection of the immigrant.. Finally, we emphasize the importance of cultural values -like Harmony or Egalitarianism- for any initiative or social policy which aimes at reducing the problems concerning inmigration in the European context.

  11. Seismic migration in generalized coordinates

    International Nuclear Information System (INIS)

    Arias, C.; Duque, L. F.

    2017-01-01

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

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

    DEFF Research Database (Denmark)

    Skov, Christian; Aarestrup, Kim; Baktoft, Henrik

    2010-01-01

    The factors that drive partial migration in organisms are not fully understood. Roach (Rutilus rutilus), a freshwater fish, engage in partial migration where parts of populations switch between summer habitats in lakes and winter habitats in connected streams. To test if the partial migration trait...

  13. 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

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

    Science.gov (United States)

    Fussell, Elizabeth; DeWaard, Jack

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-08-01

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

  16. Thermal-gradient migration of brine inclusions in salt

    International Nuclear Information System (INIS)

    Yagnik, S.K.

    1982-02-01

    It has been proposed that the high level nuclear waste be buried deep underground in a suitable geologic formation. Natural salt deposits have been under active consideration as one of the geologic formations where a nuclear waste repository may be built in future. The salt deposits, however, are known to contain a small amount (about 0.5 vol.%) of water in the form of brine inclusions which are dispersed throughout the medium. The temperature gradients imposed by the heat generating nuclear waste will mobilize these brine inclusions. It is important to know the rate and the amount of brine accumulating at the waste packages to properly evaluate the performance of a nuclear waste repository. An extensive experimental investigation of the migration velocities of brine inclusions in synthetic single crystals of NaCl and in polycrystalline natural salt crystals has been conducted. The results show that in a salt repository the brine inclusions within a grain would move with the diffusion controlled velocities. The brine reaching a grain boundary may be swept across, if the thermal gradient is high enough. Grain boundaries in polycrystalline rock salt are apparently quite weak and open up due to drilling the hole for a waste canister and to the thermal stresses which accompany the thermal gradient produced by the heat generating waste. The enhanced porosity allows the water reaching the grain boundary to escape by a vapor transport process

  17. Evaluation of element migration from food plastic packagings into simulated solutions using radiometric method

    International Nuclear Information System (INIS)

    Soares, Eufemia Paez; Saiki, Mitiko; Wiebeck, Helio

    2005-01-01

    In the present study a radiometric method was established to determine the migration of elements from food plastic packagings to a simulated acetic acid solution. This radiometric method consisted of irradiating plastic samples with neutrons at IEA-R1 nuclear reactor for a period of 16 hours under a neutron flux of 10 12 n cm -2 s -1 and, then to expose them to the element migration into a simulated solution. The radioactivity of the activated elements transferred to the solutions was measured to evaluate the migration. The experimental conditions were: time of exposure of 10 days at 40 deg C and 3% acetic acid solution was used as simulated solution, according to the procedure established by the National Agency of Sanitary Monitoring (ANVISA). The migration study was applied for plastic samples from soft drink and juice packagings. The results obtained indicated the migration of elements Co, Cr and Sb. The advantage of this methodology was no need to analyse the blank of simulantes, as well as the use of high purity simulated solutions. Besides, the method allows to evaluate the migration of the elements into the food content instead of simulated solution. The detention limits indicated high sensitivity of the radiometric method. (author)

  18. Past matrix stiffness primes epithelial cells and regulates their future collective migration through a mechanical memory.

    Science.gov (United States)

    Nasrollahi, Samila; Walter, Christopher; Loza, Andrew J; Schimizzi, Gregory V; Longmore, Gregory D; Pathak, Amit

    2017-11-01

    During morphogenesis and cancer metastasis, grouped cells migrate through tissues of dissimilar stiffness. Although the influence of matrix stiffness on cellular mechanosensitivity and motility are well-recognized, it remains unknown whether these matrix-dependent cellular features persist after cells move to a new microenvironment. Here, we interrogate whether priming of epithelial cells by a given matrix stiffness influences their future collective migration on a different matrix - a property we refer to as the 'mechanical memory' of migratory cells. To prime cells on a defined matrix and track their collective migration onto an adjoining secondary matrix of dissimilar stiffness, we develop a modular polyacrylamide substrate through step-by-step polymerization of different PA compositions. We report that epithelial cells primed on a stiff matrix migrate faster, display higher actomyosin expression, form larger focal adhesions, and retain nuclear YAP even after arriving onto a soft secondary matrix, as compared to their control behavior on a homogeneously soft matrix. Priming on a soft ECM causes a reverse effect. The depletion of YAP dramatically reduces this memory-dependent migration. Our results present a previously unidentified regulation of mechanosensitive collective cell migration by past matrix stiffness, in which mechanical memory depends on YAP activity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Atomistic simulations of void migration under thermal gradient in UO2

    International Nuclear Information System (INIS)

    Desai, Tapan G.; Millett, Paul; Tonks, Michael; Wolf, Dieter

    2010-01-01

    It is well known that within a few hours after startup of a nuclear reactor, the temperature gradient within a fuel element causes migration of voids/bubbles radially inwards to form a central hole. To understand the atomic processes that control this migration of voids, we performed molecular dynamics (MD) simulations on single crystal UO 2 with voids of diameter 2.2 nm. An external temperature gradient was applied across the simulation cell. At the end of the simulation run, it was observed that the voids had moved towards the hot end of the simulation cell. The void migration velocity obtained from the simulations was compared with the available phenomenological equations for void migration due to different transport mechanisms. Surface diffusion of the slowest moving specie, i.e. uranium, was found to be the dominant mechanism for void migration. The contribution from lattice diffusion and the thermal stress gradient to the void migration was analyzed and found to be negligible. By extrapolation, a crossover from the surface-diffusion-controlled mechanism to the lattice-diffusion-controlled mechanism was found to occur for voids with sizes in the μm range.

  20. Contaminants migration in the soil: the influence of transfer between the mobile and stationary phases

    International Nuclear Information System (INIS)

    Moreira, R.M.; Sabino, C.S.V.; Macedo, W.A.

    1996-01-01

    Three transport mechanisms control the contaminant migration in saturated soils: advection, diffusion and interchanges between liquid and solid phases. These interchanges define the retention by the soil and the contaminant delay related to the liquid phase flow. Therefore, the knowledge of the adsorption/desorption characteristics of the solute in solid surfaces is fundamental for the evaluation of toxic agent releases to the compartment soil. This communication reports the study which is being performed by the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN) in this area, particularly with cesium and mercury by using X-ray absorption spectroscopy for contaminants migration

  1. Migration from New EU Member Countries

    DEFF Research Database (Denmark)

    Pytlikova, Mariola

    2007-01-01

    The main purpose of the paper is to give predictions of the migration potential from the 7 new EU member countries to the EEA/EU-13 countries. Being able to analyze 'real' migration behavior from these particular countries over the period 1990-2000 helps me to avoid problems related to (double) o...

  2. Socio-Economic Determinants of International Migration

    Directory of Open Access Journals (Sweden)

    Yaroslav PRYTULA

    2012-05-01

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

  3. The Psychology of Puerto Rican Migration.

    Science.gov (United States)

    Prewitt Diaz, Joseph O.

    The psychology of the Puerto Rican migrant to the United States mainland is explored. Puerto Ricans have been migrating to the U.S. mainland and returning to Puerto Rico for more than 125 years, and, in fact, approximately 57% of all Puerto Ricans have migrated at one time or another. The migrant experience, including the circular migration…

  4. OECD migration, welfare and skill selectivity

    DEFF Research Database (Denmark)

    Pedersen, Peder; Pytlikova, Mariola; Smith, Nina

    into 27 OECD countries over the period of 12 years, 1989-2000. Using a fixed effects panel data model, we analyze the determinants of the migration flows during the latest decade. We study whether there are significant selectivity effects in international migration flows, i.e. whether the countries...

  5. Skeletonized Least Squares Wave Equation Migration

    KAUST Repository

    Zhan, Ge; Schuster, Gerard T.

    2010-01-01

    of the wave equation. Only the early‐arrivals of these Green's functions are saved and skeletonized to form the migration Green's function (MGF) by convolution. Then the migration image is obtained by a dot product between the recorded shot gathers and the MGF

  6. Migration and sorption phenomena in packaged foods.

    Science.gov (United States)

    Gnanasekharan, V; Floros, J D

    1997-10-01

    Rapidly developing analytical capabilities and continuously evolving stringent regulations have made food/package interactions a subject of intense research. This article focuses on: (1) the migration of package components such as oligomers and monomers, processing aids, additives, and residual reactants in to packaged foods, and (2) sorption of food components such as flavors, lipids, and moisture into packages. Principles of diffusion and thermodynamics are utilized to describe the mathematics of migration and sorption. Mathematical models are developed from first principles, and their applicability is illustrated using numerical simulations and published data. Simulations indicate that available models are system (polymer-penetrant) specific. Furthermore, some models best describe the early stages of migration/sorption, whereas others should be used for the late stages of these phenomena. Migration- and/or sorption-related problems with respect to glass, metal, paper-based and polymeric packaging materials are discussed, and their importance is illustrated using published examples. The effects of migrating and absorbed components on food safety, quality, and the environment are presented for various foods and packaging materials. The impact of currently popular packaging techniques such as microwavable, ovenable, and retortable packaging on migration and sorption are discussed with examples. Analytical techniques for investigating migration and sorption phenomena in food packaging are critically reviewed, with special emphasis on the use and characteristics of food-simulating liquids (FSLs). Finally, domestic and international regulations concerning migration in packaged foods, and their impact on food packaging is briefly presented.

  7. Do migrating cells need a nucleus?

    Science.gov (United States)

    Hawkins, Rhoda J

    2018-03-05

    How the nucleus affects cell polarity and migration is unclear. In this issue, Graham et al. (2018. J. Cell Biol. https://doi.org/10.1083/jcb.201706097) show that enucleated cells polarize and migrate in two but not three dimensions and propose that the nucleus is a necessary component of the molecular clutch regulating normal mechanical responses. © 2018 Hawkins.

  8. Service Migration Protocol for NFC Links

    DEFF Research Database (Denmark)

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

    2010-01-01

    of use while preserving state. This paper focuses on the scenario of migration between two devices in which the actual migration procedure is executed over near-field communication (NFC) ad-hoc links. The NFC link is interesting as it gives the user the perception of trust and enables service continuity...

  9. Intraperitoneal stone migration during percutaneos nephrolithotomy

    Directory of Open Access Journals (Sweden)

    Akif Diri

    2014-12-01

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

  10. The External Dimension of EU Migration Policy

    Directory of Open Access Journals (Sweden)

    Dorina Gjipali

    2017-01-01

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

  11. 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...

  12. Elastic kirchhoff migration for vertical seismic profiles

    International Nuclear Information System (INIS)

    Keho, T.H.; Wu, R.S.

    1987-01-01

    Elastic Kirchhoff migration is implemented for the VSP recording geometry. The resulting migration formula requires measurement of the stress as well as the displacement. Since stress is not measured in a VSP, and in many cases the horizontal component of displacement is not measured, approximate migration formulas are given for these cases. The elastic migration formula for the case where only the vertical components are available, is the same as the acoustic migration formula, where the pressure data are replaced by the magnitudes of the elastic data as reconstructed from the vertical components, and the acoustic Green's functions are replaced with either the P or S wave elastic Green's functions. Two expressions for migration of two component displacement data are presented. In the first, the terms involving traction data are simply ignored. In the second, an improved backpropagation operator for the displacement field is obtained by replacing the traction data in the Kirchhoff integral by displacement data using Hooke's law. The migration expressions for the cases where two component data are available produce images which are less contaminated by artifacts than the migration images of one component data

  13. The role of 'conservatism' in herring migrations

    NARCIS (Netherlands)

    Corten, A.

    2002-01-01

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

  14. SHARPIN Regulates Uropod Detachment in Migrating Lymphocytes

    Directory of Open Access Journals (Sweden)

    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. Integrating meteorology into research on migration

    NARCIS (Netherlands)

    Shamoun-Baranes, J.; Bouten, W.; van Loon, E.E.

    2010-01-01

    Atmospheric dynamics strongly influence the migration of flying organisms. They affect, among others, the onset, duration and cost of migration, migratory routes, stop-over decisions, and flight speeds en-route. Animals move through a heterogeneous environment and have to react to atmospheric

  16. Migration control, documentation, and state transformation

    NARCIS (Netherlands)

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

    2011-01-01

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

  17. Ethical issues in irregular migration research

    NARCIS (Netherlands)

    Duvell, F.; Triandafyllidou, A.; Vollmer, B.

    2008-01-01

    This paper is concerned with the ethical issues arising for researchers engaged in the study of irregular migration. Irregular migration is by definition an elusive phenomenon as it takes place in violation of the law and at the margins of society. This very nature of the phenomenon raises important

  18. 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…

  19. Gender and Internal Migration dynamics in Ghana

    African Journals Online (AJOL)

    Agribotix GCS 068

    Internal migration is an inherent part of the processes of development and structural ... to rural-urban migrants by Government policies and strategies to enhance the ... Several studies globally indicate that migration is a driver of growth and an .... More recent approaches of networks theories and transnational approaches to ...

  20. Investigation of acetyl migrations in furanosides

    Directory of Open Access Journals (Sweden)

    Migaud ME

    2006-07-01

    Full Text Available Abstract Standard reaction conditions for the desilylation of acetylated furanoside (riboside, arabinoside and xyloside derivatives facilitate acyl migration. Conditions which favour intramolecular and intermolecular mechanisms have been identified with intermolecular transesterifications taking place under mild basic conditions when intramolecular orthoester formations are disfavoured. In acetyl ribosides, acyl migration could be prevented when desilylation was catalysed by cerium ammonium nitrate.

  1. Husbands' return migration and wives' occupational choices

    NARCIS (Netherlands)

    Mahe, Clotilde

    2017-01-01

    Exploiting the documented effect of migration on occupational choice upon return to their origin country with data from Egypt, we establish a link between return migration of men and their wives' time use through within-couple occupational interdependence. Seemingly Unrelated Regression model

  2. Migration and rural development in the Caribbean.

    Science.gov (United States)

    Momsen, J D

    1986-01-01

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

  3. Nuclear rights - nuclear wrongs

    Energy Technology Data Exchange (ETDEWEB)

    Paul, E.F.; Miller, F.D.; Paul, J.; Ahrens, J.

    1986-01-01

    This book contains 11 selections. The titles are: Three Ways to Kill Innocent Bystanders: Some Conundrums Concerning the Morality of War; The International Defense of Liberty; Two Concepts of Deterrence; Nuclear Deterrence and Arms Control; Ethical Issues for the 1980s; The Moral Status of Nuclear Deterrent Threats; Optimal Deterrence; Morality and Paradoxical Deterrence; Immoral Risks: A Deontological Critique of Nuclear Deterrence; No War Without Dictatorship, No Peace Without Democracy: Foreign Policy as Domestic Politics; Marxism-Leninism and its Strategic Implications for the United States; Tocqueveille War.

  4. Nuclear moments

    CERN Document Server

    Kopferman, H; Massey, H S W

    1958-01-01

    Nuclear Moments focuses on the processes, methodologies, reactions, and transformations of molecules and atoms, including magnetic resonance and nuclear moments. The book first offers information on nuclear moments in free atoms and molecules, including theoretical foundations of hyperfine structure, isotope shift, spectra of diatomic molecules, and vector model of molecules. The manuscript then takes a look at nuclear moments in liquids and crystals. Discussions focus on nuclear paramagnetic and magnetic resonance and nuclear quadrupole resonance. The text discusses nuclear moments and nucl

  5. 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

  6. 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

  7. Effects of particles on macrophage migration

    International Nuclear Information System (INIS)

    Mueller, H.L.; Robinson, B.; Muggenburg, B.A.; Guilmette, R.A.

    1988-01-01

    Random and directed migration of cells lavaged from the lungs of rats and dogs were studied in vitro using formyl-methionyl-leucyl-phenylalanine (FMLP) as a chemo attractant. Rats and dogs were intratracheally instilled with either saline (controls) or about 10 9 fluorescent polystyrene microspheres, and lungs were lavaged after 1 or 7 days. More rat cells than dog cells migrated at 1 day after both particle and saline instillations; at 7 days, only cells lavaged from rats after particle instillations showed enhanced migration abilities. FMLP caused a 1.5 to 2-fold enhancement compared to random migration in cell numbers counted on the lower sides of chemotactic membranes. Cells with low particle numbers were more likely to migrate than those with high numbers of ingested particles. (author)

  8. LHCb migration from Subversion to Git

    Science.gov (United States)

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

    2017-10-01

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

  9. Aspects of general linear modelling of migration.

    Science.gov (United States)

    Congdon, P

    1992-01-01

    "This paper investigates the application of general linear modelling principles to analysing migration flows between areas. Particular attention is paid to specifying the form of the regression and error components, and the nature of departures from Poisson randomness. Extensions to take account of spatial and temporal correlation are discussed as well as constrained estimation. The issue of specification bears on the testing of migration theories, and assessing the role migration plays in job and housing markets: the direction and significance of the effects of economic variates on migration depends on the specification of the statistical model. The application is in the context of migration in London and South East England in the 1970s and 1980s." excerpt

  10. 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.

  11. Undocumented migration in response to climate change.

    Science.gov (United States)

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

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

  12. Radiation-induced electron migration along DNA

    International Nuclear Information System (INIS)

    Fuciarelli, A.F.; Sisk, E.C.; Miller, J.H.; Zimbrick, J.D.

    1994-04-01

    Radiation-induced electron migration along DNA is a mechanism by which randomly produced stochastic energy deposition events can lead to nonrandom types of damage along DNA manifested distal to the sites of the initial energy deposition. Electron migration along DNA is significantly influenced by the DNA base sequence and DNA conformation. Migration along 7 base pairs in oligonucleotides containing guanine bases was observed for oligonucleotides irradiated in solution which compares to average migration distances of 6 to 10 bases for Escherichia coli DNA irradiated in solution and 5.5 base pairs for Escherichia coli DNA irradiated in cells. Evidence also suggests that electron migration can occur preferentially in the 5' to 3' direction along DNA. Our continued efforts will provide information regarding the contribution of electron transfer along DNA to formation of locally multiply damaged sites created in DNA by exposure to ionizing radiation

  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. Hedgehog signaling contributes to basic fibroblast growth factor-regulated fibroblast migration

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Zhong Xin [School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China); Sun, Cong Cong [School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China); Wenzhou People' s Hospital, Wenzhou, Zhejiang (China); Ting Zhu, Yu; Wang, Ying; Wang, Tao; Chi, Li Sha; Cai, Wan Hui [School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China); Zheng, Jia Yong [Wenzhou People' s Hospital, Wenzhou, Zhejiang (China); Zhou, Xuan [Ningbo First Hospital, Ningbo, Zhejiang (China); Cong, Wei Tao [School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China); Li, Xiao Kun, E-mail: proflxk@163.com [School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China); Jin, Li Tai, E-mail: jin_litai@126.com [School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China)

    2017-06-15

    Fibroblast migration is a central process in skin wound healing, which requires the coordination of several types of growth factors. bFGF, a well-known fibroblast growth factor (FGF), is able to accelerate fibroblast migration; however, the underlying mechanism of bFGF regulation fibroblast migration remains unclear. Through the RNA-seq analysis, we had identified that the hedgehog (Hh) canonical pathway genes including Smoothened (Smo) and Gli1, were regulated by bFGF. Further analysis revealed that activation of the Hh pathway via up-regulation of Smo promoted fibroblast migration, invasion, and skin wound healing, but which significantly reduced by GANT61, a selective antagonist of Gli1/Gli2. Western blot analyses and siRNA transfection assays demonstrated that Smo acted upstream of phosphoinositide 3-kinase (PI3K)-c-Jun N-terminal kinase (JNK)-β-catenin to promote cell migration. Moreover, RNA-seq and qRT-PCR analyses revealed that Hh pathway genes including Smo and Gli1 were under control of β-catenin, suggesting that β-catenin turn feedback activates Hh signaling. Taken together, our analyses identified a new bFGF-regulating mechanism by which Hh signaling regulates human fibroblast migration, and the data presented here opens a new avenue for the wound healing therapy. - Highlights: • bFGF regulates Hedgehog (Hh) signaling in fibroblasts. • The Smo and Gli two master regulators of Hh signaling positively regulate fibroblast migration. • Smo facilitates β-catenin nuclear translocation via activation PI3K/JNK/GSK3β. • β-catenin positively regulates fibroblast cell migration and the expression of Hh signaling genes including Smo and Gli.

  15. Hedgehog signaling contributes to basic fibroblast growth factor-regulated fibroblast migration

    International Nuclear Information System (INIS)

    Zhu, Zhong Xin; Sun, Cong Cong; Ting Zhu, Yu; Wang, Ying; Wang, Tao; Chi, Li Sha; Cai, Wan Hui; Zheng, Jia Yong; Zhou, Xuan; Cong, Wei Tao; Li, Xiao Kun; Jin, Li Tai

    2017-01-01

    Fibroblast migration is a central process in skin wound healing, which requires the coordination of several types of growth factors. bFGF, a well-known fibroblast growth factor (FGF), is able to accelerate fibroblast migration; however, the underlying mechanism of bFGF regulation fibroblast migration remains unclear. Through the RNA-seq analysis, we had identified that the hedgehog (Hh) canonical pathway genes including Smoothened (Smo) and Gli1, were regulated by bFGF. Further analysis revealed that activation of the Hh pathway via up-regulation of Smo promoted fibroblast migration, invasion, and skin wound healing, but which significantly reduced by GANT61, a selective antagonist of Gli1/Gli2. Western blot analyses and siRNA transfection assays demonstrated that Smo acted upstream of phosphoinositide 3-kinase (PI3K)-c-Jun N-terminal kinase (JNK)-β-catenin to promote cell migration. Moreover, RNA-seq and qRT-PCR analyses revealed that Hh pathway genes including Smo and Gli1 were under control of β-catenin, suggesting that β-catenin turn feedback activates Hh signaling. Taken together, our analyses identified a new bFGF-regulating mechanism by which Hh signaling regulates human fibroblast migration, and the data presented here opens a new avenue for the wound healing therapy. - Highlights: • bFGF regulates Hedgehog (Hh) signaling in fibroblasts. • The Smo and Gli two master regulators of Hh signaling positively regulate fibroblast migration. • Smo facilitates β-catenin nuclear translocation via activation PI3K/JNK/GSK3β. • β-catenin positively regulates fibroblast cell migration and the expression of Hh signaling genes including Smo and Gli.

  16. 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

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

    NARCIS (Netherlands)

    Kuschminder - de Guerre, Katie; Koser, Khalid

    2017-01-01

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

  18. Nuclear waste repository simulation experiments

    International Nuclear Information System (INIS)

    Rothfuchs, T.; Wieczorek, K.; Feddersen, H.K.; Staupendahl, G.; Coyle, A.J.; Kalia, H.; Eckert, J.

    1986-12-01

    This document is the third joint annual report on the Cooperative German-American 'Brine Migration Tests' that are in progress at the Asse salt mine in the Federal Republic of Germany (FRG). This Government supported mine serves as an underground test facility for research and development (R and D)-work in the field of nuclear waste repository research and simulation experiments. The tests are designed to simulate a nuclear waste repository to measure the effects of heat and gamma radiation on brine migration, salt decrepitation, disassociation of brine, and gases collected. The thermal mechanical behavior of salt, such as room closure, stresses and changes of the properties of salt are measured and compared with predicted behavior. This document covers the following sections: Issues and test objectives: This section presents issues that are investigated by the Brine Migration Test, and the test objectives derived from these issues; test site: This section describes the test site location and geology in the Asse mine; test description: A description of the test configuration, procedures, equipment, and instrumentation is given in this section; actual test chronology: The actual history of the test, in terms of the dates at which major activities occured, is presented in this section. Test results: This section presents the test results observed to data and the planned future work that is needed to complete the test; conclusions and recommendations: This section summarizes the conclusions derived to date regarding the Brine Migration Test. Additional work that would be useful to resolve the issues is discussed. (orig.)

  19. Annual spatiotemporal migration schedules in three larger insectivorous birds

    DEFF Research Database (Denmark)

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

    2017-01-01

    Background: Knowledge of spatiotemporal migration patterns is important for our understanding of migration ecology and ultimately conservation of migratory species. We studied the annual migration schedules of European nightjar, a large nocturnal insectivore and compared it with two other larger ...

  20. Mitigation of artifacts in rtm with migration kernel decomposition

    KAUST Repository

    Zhan, Ge; Schuster, Gerard T.

    2012-01-01

    The migration kernel for reverse-time migration (RTM) can be decomposed into four component kernels using Born scattering and migration theory. Each component kernel has a unique physical interpretation and can be interpreted differently

  1. Prediction and Migration of Surface-related Resonant Multiples

    KAUST Repository

    Guo, Bowen; Schuster, Gerard T.; Huang, Yunsong

    2015-01-01

    Surface-related resonant multiples can be migrated to achieve better resolution than migrating primary reflections. We now derive the formula for migrating surface-related resonant multiples, and show its super-resolution characteristics. Moreover

  2. Nuclear waste vault sealing

    International Nuclear Information System (INIS)

    Gyenge, M.

    1980-01-01

    A nuclear waste vault must be designed and built to ensure adequate isolation of the nuclear wastes from human contact. Consequently, after a vault has been fully loaded, it must be adequately sealed off to prevent radionuclide migration which may be provided by circulating groundwater. Vault sealing entails four major aspects, i.e.: (a) vault grouting; (b) borehole sealing; (c) buffer packing; and (d) backfilling. Of particular concern in vault sealing are the physical and chemical properties of the sealing material, its long-term durability and stability, and the techniques used for its emplacement. Present sealing technology and sealing materials are reviewed in terms of the particular needs of vault sealing. Areas requiring research and development are indicated

  3. Surface migration in sorption processes

    International Nuclear Information System (INIS)

    Rasmuson, A.; Neretnieks, J.

    1983-03-01

    Diffusion rates of sorbing chemical species in granites and clays are in several experiments within the KBS study, higher than can be explained by pore diffusion only. One possible additional transport mechanism is transport of of sorbed molecules/ions along the intrapore surfaces. As a first step a literature investigation on on solid surfaces has been conducted. A lot of experimental evidence of the mobility of the sorbed molecules has been gathered through the years, particulary for metal surfaces and chemical engineering systems. For clays however, there are only a few articles, and for granites none. Two types of surface migration models have been proposed in the litterature: i) Surface flow as a result of a gradient in spreading pressure. ii) Surface diffusion as a result of a gradient in concentration. The surface flow model has only been applied to gaseous systems. However, it should be equally applicable to liquid systems. The models i) and ii) are conceptually very different. However, the resulting expressions for surface flux are complicated and it will not be an easy task to distinguish between them. There seem to be three ways of discriminating between the transport mechanisms: a) Temperature dependence. b) Concentration dependence. c) Order of magnitude. (Forf)

  4. Stem cell migration after irradiation

    International Nuclear Information System (INIS)

    Nothdurft, W.; Fliedner, T.M.

    1979-01-01

    The survival rate of irradiated rodents could be significantly improved by shielding only the small parts of hemopoietic tissues during the course of irradiation. The populations of circulating stem cells in adult organisms are considered to be of some importance for the homeostasis between the many sites of blood cell formation and for the necessary flexibility of hemopoietic response in the face of fluctuating demands. Pluripotent stem cells are migrating through peripheral blood as has been shown for several mammalian species. Under steady state conditions, the exchange of stem cells between the different sites of blood cell formation appears to be restricted. Their presence in blood and the fact that they are in balance with the extravascular stem cell pool may well be of significance for the surveilance of the integrity of local stem cell populations. Any decrease of stem cell population in blood below a critical size results in the rapid immigration of circulating stem cells in order to restore local stem cell pool size. Blood stem cells are involved in the regeneration after whole-body irradiation if the stem cell population in bone marrows is reduced to less than 10% of the normal state. In the animals subjected to partial-body irradiation, the circulating stem cells appear to be the only source for the repopulation of the heavily irradiated, aplastic sites of hemopoietic organs. (Yamashita, S.)

  5. Gas migration in argillaceous rock

    International Nuclear Information System (INIS)

    Alonso, E. E.; Olivella, S.

    2007-01-01

    The intrinsic gas permeability of fractured argillaceous rocks depends on the current structure of micro-cracks and fissures of the rock. They are a consequence of the initial state and the subsequent deformations induced by stress and gas pressure changes. Stresses are also coupled with fluid pressures and, therefore, gas flow and mechanical behaviour are intensely coupled. Laboratory experiments, aimed at determining intrinsic permeability, show the relevant effect of volumetric deformations induced by isotropic, as well as deviatoric stress changes. The relevance, in practice, of the flow-mechanical coupling is illustrated by means of some results obtained during the performance of the drift scale test (DST) in fractured tuff in the Yucca Mountain facility. The technique of embedding discontinuities in continuum thermo-hydro-mechanical elements is capable of reproducing observed features of gas flow migration in clayey rocks. An example is described. It is believed that the developed approach provides a powerful computational procedure to handle complex gas phenomena in clayey rocks. (author)

  6. 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.

  7. Mitigation of artifacts in rtm with migration kernel decomposition

    KAUST Repository

    Zhan, Ge

    2012-01-01

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

  8. International migration desires related to subjective well-being

    OpenAIRE

    Cai, Ruohong; Esipova, Neli; Oppenheimer, Michael; Feng, Shuaizhang

    2014-01-01

    Previous research on the determinants of international migration has largely focused on objective factors, such as income. We instead use subjective well-being (SWB) to explain international migration desires, an expressed willingness to migrate. We find that individuals with higher SWB have lower international migration desires. At the individual level, the SWB-migration relationship appears to be more robust than the income-migration relationship. At the country level, national average SWB ...

  9. 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

  10. DO GIANT PLANETS SURVIVE TYPE II MIGRATION?

    International Nuclear Information System (INIS)

    Hasegawa, Yasuhiro; Ida, Shigeru

    2013-01-01

    Planetary migration is one of the most serious problems to systematically understand the observations of exoplanets. We clarify that the theoretically predicted type II, migration (like type I migration) is too fast, by developing detailed analytical arguments in which the timescale of type II migration is compared with the disk lifetime. In the disk-dominated regime, the type II migration timescale is characterized by a local viscous diffusion timescale, while the disk lifetime is characterized by a global diffusion timescale that is much longer than the local one. Even in the planet-dominated regime where the inertia of the planet mass reduces the migration speed, the timescale is still shorter than the disk lifetime except in the final disk evolution stage where the total disk mass decays below the planet mass. This suggests that most giant planets plunge into the central stars within the disk lifetime, and it contradicts the exoplanet observations that gas giants are piled up at r ∼> 1 AU. We examine additional processes that may arise in protoplanetary disks: dead zones, photoevaporation of gas, and gas flow across a gap formed by a type II migrator. Although they make the type II migration timescale closer to the disk lifetime, we show that none of them can act as an effective barrier for rapid type II migration with the current knowledge of these processes. We point out that gas flow across a gap and the fraction of the flow accreted onto the planets are uncertain and they may have the potential to solve the problem. Much more detailed investigation for each process may be needed to explain the observed distribution of gas giants in extrasolar planetary systems

  11. 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.

  12. Numerical Modeling Tools for the Prediction of Solution Migration Applicable to Mining Site

    International Nuclear Information System (INIS)

    Martell, M.; Vaughn, P.

    1999-01-01

    Mining has always had an important influence on cultures and traditions of communities around the globe and throughout history. Today, because mining legislation places heavy emphasis on environmental protection, there is great interest in having a comprehensive understanding of ancient mining and mining sites. Multi-disciplinary approaches (i.e., Pb isotopes as tracers) are being used to explore the distribution of metals in natural environments. Another successful approach is to model solution migration numerically. A proven method to simulate solution migration in natural rock salt has been applied to project through time for 10,000 years the system performance and solution concentrations surrounding a proposed nuclear waste repository. This capability is readily adaptable to simulate solution migration around mining

  13. Reelin signaling in the migration of ventral brain stem and spinal cord neurons

    Directory of Open Access Journals (Sweden)

    Sandra eBlaess

    2016-03-01

    Full Text Available The extracellular matrix protein Reelin is an important orchestrator of neuronal migration during the development of the central nervous system. While its role and mechanism of action have been extensively studied and reviewed in the formation of dorsal laminar brain structures like the cerebral cortex, hippocampus, and cerebellum, its functions during the neuronal migration events that result in the nuclear organization of the ventral central nervous system are less well understood. In an attempt to delineate an underlying pattern of Reelin action in the formation of neuronal cell clusters, this review highlights the role of Reelin signaling in the migration of neuronal populations that originate in the ventral brain stem and the spinal cord.

  14. Migration of brine inclusions in salt

    International Nuclear Information System (INIS)

    Pigford, T.H.

    1982-01-01

    Theories of the migration of brine inclusions in salt are interpreted as simple physical processes, and theories by Russian and U.S. workers are shown to yield the same results. The migration theory is used to predict threshold temperature gradients below which migration of brine inclusions should not occur. The predicted threshold gradients are compared with the temperature gradients expected at the Waste Isolation Pilot Plant in New Mexico. The theory of a threshold gradient helps explain the existence of brine inclusions in natural salt deposits

  15. Urban squatting and migration in Peninsular Malaysia.

    Science.gov (United States)

    Johnstone, M

    1983-01-01

    "This article examines some of the links between the phenomena of urban migration and squatter settlements in the Third World city. This will be done by demonstrating that both are outcomes of fundamental social and political forces that have operated on these societies. Migration and squatting are placed in a context of the historical processes that led to the uneven development of Malaysia. The article offers some explanation for the origin of the inequalities observed in spatial structures--in this case urban housing--by focusing on one of the contributory factors, namely migration." excerpt

  16. Determinants of internal migration in Kazakhstan

    OpenAIRE

    Aldashev, Alisher; Dietz, Barbara

    2011-01-01

    In this paper we analyze the determinants of interregional migration in Kazakhstan using quarterly panel data on region to region migration in 2008–2010. To the best of our knowledge this is the first study on interregional population flows in Central Asia. We find that migration is determined by economic factors, first of all income: People are more likely to leave regions where incomes are low and more likely to move to regions with a higher income level. Furthermore, mobility is larger bet...

  17. 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

  18. The determinants of internal migration in Turkey

    OpenAIRE

    Gökhan, Ali; Gokhan, Ali; Filiztekin, Alpay

    2008-01-01

    Internal migration has had a great impact on Turkey’s population dynamics for decades. According to the 2000 population census, nearly 28% percent of the population was born in a different province that they now reside in. This ratio goes up to 62% for Istanbul, a major province that has drawn migrants for years. Although, it is claimed in numerous studies that rural-urban migration that centers on a few urban areas seems to be the predominant pattern of internal migration, we aim to investig...

  19. 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

  20. Transverse entanglement migration in Hilbert space

    International Nuclear Information System (INIS)

    Chan, K. W.; Torres, J. P.; Eberly, J. H.

    2007-01-01

    We show that, although the amount of mutual entanglement of photons propagating in free space is fixed, the type of correlations between the photons that determine the entanglement can dramatically change during propagation. We show that this amounts to a migration of entanglement in Hilbert space, rather than real space. For the case of spontaneous parametric down-conversion, the migration of entanglement in transverse coordinates takes place from modulus to phase of the biphoton state and back again. We propose an experiment to observe this migration in Hilbert space and to determine the full entanglement

  1. 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

  2. Migration and Literature

    DEFF Research Database (Denmark)

    Frank, Søren

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

  3. 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.

  4. Nuclear power

    International Nuclear Information System (INIS)

    Abd Khalik Wood

    2005-01-01

    This chapter discussed the following topics related to the nuclear power: nuclear reactions, nuclear reactors and its components - reactor fuel, fuel assembly, moderator, control system, coolants. The topics titled nuclear fuel cycle following subtopics are covered: , mining and milling, tailings, enrichment, fuel fabrication, reactor operations, radioactive waste and fuel reprocessing. Special topic on types of nuclear reactor highlighted the reactors for research, training, production, material testing and quite detail on reactors for electricity generation. Other related topics are also discussed: sustainability of nuclear power, renewable nuclear fuel, human capital, environmental friendly, emission free, impacts on global warming and air pollution, conservation and preservation, and future prospect of nuclear power

  5. Changes in Nuclear Structure During Wheat Endosperm Development

    NARCIS (Netherlands)

    Wegel, E.

    2005-01-01

    This thesis is an investigation into the structure of wheat endosperm nuclei starting with nuclear divisions and migration during syncytium formation followed by the development of nuclear shape and positioning of chromosome territories and ending with changes in subchromosomal structure during the

  6. Hydrology and radionuclide migration program

    International Nuclear Information System (INIS)

    Marsh, K.V.

    1992-02-01

    This report presents results from the Lawrence Livermore National Laboratory's participation in the Hydrology and Radionuclide Migration Program at the Nevada Test Site (NTS) during fiscal year 1988. The report discusses studies at a new well 100 m down the hydrologic gradient from the previous sampling point at the Cheshire site; laboratory investigations of the mineralogical composition of NTS colloids; the strength of colloidal deposits and parameters affecting their formation and release; accelerator mass spectrometric measurements of 129 I in water from the Cheshire stie; 222 Rn concentrations in water from several pumped wells at the NTS; and a description of a new well (PM3) drilled off the NTS near Area 20. Further studies on groundwater sampled show that both technetium and iodine are quite mobile; both closely track the trend of the decreasing tritium concentration with increasing distance. Antimony and cesium concentrations decrease much more rapidly than tritium, and europium was not detected at all in the new well. Colloidal particles found in water collected from the Cheshire cavity are in size range of 0.050 to 0.003 μm and are dominated by quartz and (Ca, K) feldspars. A new well was drilled on US Air Force land adjacent to the NTS Area 20. Static water level measurements and geochemical data from this well will help to determine the extent to which Pahute Mesa base flow infiltrates Oasis Valley. Preliminary results indicate tritium concentrations in water samples from this well to be in the range of 0.1 to 0.4 pCi/ml as measured under field conditions

  7. Total glucosides of paeony inhibits lipopolysaccharide-induced proliferation, migration and invasion in androgen insensitive prostate cancer cells.

    Directory of Open Access Journals (Sweden)

    Zhi-Hui Zhang

    Full Text Available Previous studies demonstrated that inflammatory microenvironment promoted prostate cancer progression. This study investigated whether total glucosides of paeony (TGP, the active constituents extracted from the root of Paeonia Lactiflora Pall, suppressed lipopolysaccharide (LPS-stimulated proliferation, migration and invasion in androgen insensitive prostate cancer cells. PC-3 cells were incubated with LPS (2.0 μg/mL in the absence or presence of TGP (312.5 μg /mL. As expected, cells at S phase and nuclear CyclinD1, the markers of cell proliferation, were increased in LPS-stimulated PC-3 cells. Migration activity, as determined by wound-healing assay and transwell migration assay, and invasion activity, as determined by transwell invasion assay, were elevated in LPS-stimulated PC-3 cells. Interestingly, TGP suppressed LPS-stimulated PC-3 cells proliferation. Moreover, TGP inhibited LPS-stimulated migration and invasion of PC-3 cells. Additional experiment showed that TGP inhibited activation of nuclear factor kappa B (NF-κB and mitogen-activated protein kinase (MAPK/p38 in LPS-stimulated PC-3 cells. Correspondingly, TGP attenuated upregulation of interleukin (IL-6 and IL-8 in LPS-stimulated PC-3 cells. In addition, TGP inhibited nuclear translocation of signal transducer and activator of transcription 3 (STAT3 in LPS-stimulated PC-3 cells. These results suggest that TGP inhibits inflammation-associated STAT3 activation and proliferation, migration and invasion in androgen insensitive prostate cancer cells.

  8. A Chaos Theory Perspective on International Migration

    Directory of Open Access Journals (Sweden)

    Anca Tănasie

    2017-12-01

    Full Text Available This paper aims at providing a different approach to international migration analysis, beyond classical models previously proposed by specialized literature. Chaos theory is getting more and more applied into macroeconomics once traditional linear models or even previous dynamic analysis become less suitable. Modern science sees chaos as unpredictable evolution, maybe even disorder. Still, chaos has got its own rules and can describe many dynamic phenomena within our world. Thus, we test whether international migration data falls under the rules of chaos and whether recent developments within the “European migration crisis” (the total daily migration inflows towards the coasts of Italy, by sea, from January 2014 to April 2017 could be described as chaotic.

  9. Multisource Least-squares Reverse Time Migration

    KAUST Repository

    Dai, Wei

    2012-01-01

    is implemented with random time-shift and random source polarity encoding functions. Numerical tests on the 2D HESS VTI data show that the multisource LSRTM algorithm suppresses migration artifacts, balances the amplitudes, improves image resolution, and reduces

  10. The possibilities of compressed sensing based migration

    KAUST Repository

    Aldawood, Ali; Hoteit, Ibrahim; Alkhalifah, Tariq Ali

    2013-01-01

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

  11. Managing International Labour Migration in ASEAN | IDRC ...

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

    ... of managing labour migration flows are varied, however, and in many cases uncoordinated. ... Indonesia, Malaysia, Singapore and Thailand to undertake joint research on ... IDRC invites applications for the IDRC Research Awards 2019.

  12. The possibilities of compressed sensing based migration

    KAUST Repository

    Aldawood, Ali

    2013-09-22

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

  13. Migration of supervisory machine control architectures

    NARCIS (Netherlands)

    Graaf, B.; Weber, S.; Deursen, van A.; Nord, R.; Medvidovic, N.; Krikhaar, R.; Stafford, J.; Bosch, J.

    2005-01-01

    In this position paper, we discuss a first step towards an approach for the migration of supervisory machine control (SMC) architectures. This approach is based on the identification of SMC concerns and the definition of corresponding transformation rules.

  14. 66 THE CHALLENGES OF MIGRATION AND TECHNOLOGICAL ...

    African Journals Online (AJOL)

    Africa. Migration and African technological development have been two paradoxical or polarized ... slave trade, trafficking in human beings and ethnic cleansing. People .... It is also clear that development does not start with goods and things ...

  15. Mechanism of constitution liquid film migration

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Hongjun [Univ. of Alabama, Birmingham, AL (United States)

    1999-06-01

    Liquid film migration (LFM) in liquid phase sintering classically involves a large metastable liquid volume adjacent to solid, and migration occurs at an isolated solid-liquid (S-L) interface. Constitutional liquid film migration (CLFM), discovered in alloy 718, has major characteristics similar to those of LFM, except that the metastable liquid is from the constitutional liquation of precipitates on the grain boundary. The similarity between LFM and CLFM has led to the theory that coherency lattice strain responsible for LFM is also responsible for CLFM. The coherency strain hypothesis was tested in this study by evaluating whether the Hillert model of LFM would also apply for CLFM. Experimental results of CLFM in alloy 718 showed that migration velocity followed the trend predicted by the Hillert model. This indicates that the coherency strain hypothesis of LFM also applies for CLFM and that the coherency lattice strain responsible for LFM is also the driving force for CLFM.

  16. Reasons for doctor migration from South Africa

    African Journals Online (AJOL)

    Push factors motivating migration most frequently include dissatisfaction with ... The year of graduation ranged from 1964 to 2000 (median 1985), and the year of leaving ... South African doctors working in Canada had increased by more than.

  17. Investigations of pollutant migration using lysimeters

    International Nuclear Information System (INIS)

    Klotz, D.

    2002-01-01

    The third GSF Lysimeter Workshop focused on pollutant migration in underground strata, i.e. the dispersion of water constituents as referred to water transport on the basis of ideal tracer investigations [de

  18. Globalization, migration and underdevelopment in West Africa ...

    African Journals Online (AJOL)

    Globalization, migration and underdevelopment in West Africa. ... PROMOTING ACCESS TO AFRICAN RESEARCH ... However, globalization has put a new spin on igration, which results in greater economic opportunities for the developed ...

  19. Globalization, Migration, and Local Communities, one adverse ...

    African Journals Online (AJOL)

    Globalization, Migration, and Local Communities, one adverse upshot: A Case Review of ... PROMOTING ACCESS TO AFRICAN RESEARCH ... Historically, the lack of highly skilled labour in South Africa has been linked to the legacy of ...

  20. Migration of Cells in a Social Context

    DEFF Research Database (Denmark)

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

    2013-01-01

    In multicellular organisms and complex ecosystems, cells migrate in a social context. While this is essential for the basic processes of life such as embryonic development, wound healing and unregulated migration furthermore is implicated in diseases such as cancer, the influence of neighboring...... cells on the individual remains poorly understood. Previous work on isolated cells has revealed a stereotypical migratory behavior, however many aspects of the migration characteristics of cells in populations remained unknown exactly because of this lack of characterization of neighbour-cell influence....... We quantified1 the migration of thousands of individual cells in their population context using time-lapse microscopy, microfluidic cell culture and automated image analysis, and discovered a much richer dynamics in the social context, with significant variations in directionality, displacement...

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

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

    Migration, Rural Poverty and Community Natural Resource Management in Cambodia. Cambodia has a ... Cambodia, Far East Asia, Central Asia, South Asia ... Call for new OWSD Fellowships for Early Career Women Scientists now open.

  2. Migration from atolls as climate change adaptation

    DEFF Research Database (Denmark)

    Birk, Thomas Ladegaard Kümmel; Rasmussen, Kjeld

    2014-01-01

    to migration that reduce the efficacy of positive outcomes to both migrants and their home communities, including high transport costs and problems in gaining access to housing, employment and government services in urban destination areas. If it is accepted that voluntary migration may play a positive role...... that migration currently improves access to financial and social capital, reduces pressure on natural resources and makes island communities less vulnerable to extreme weather events and other shocks — all factors that contribute positively to adaptive capacity. It also shows that there are major barriers...... in adaptation to climate change in exposed atoll communities, addressing some of the barriers to migration seems logical. This may be done by efforts to stimulate migrant income opportunities, by improving migrant living conditions and by improving the transport services to the islands....

  3. 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.

  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. Urbanism, Migration, and Tolerance: A Reassessment.

    Science.gov (United States)

    Wilson, Thomas C.

    1991-01-01

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

  6. Floods and migration in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Stojanov, R.; Kelman, I.; Duží, Barbora

    -, 49 May 2015 (2015), s. 49-50 ISSN 1460-9819 Institutional support: RVO:68145535 Keywords : migration * flood * household Subject RIV: DJ - Water Pollution ; Quality http://www.fmreview.org/climatechange-disasters/stojanov-kelman-duzi

  7. Informatics for analysis of nuclear experiments: TOUTATIX

    International Nuclear Information System (INIS)

    Rabasse, J.F.; Du, S.; Penillault, G.; Tassan-Got, L.; Givort, M.

    1999-01-01

    For several years in connection with the migration towards UNIX system, software tools have been developed in the laboratory. They allow the nuclear physicist community to achieve the complete analysis of experimental data. They comply with the requirements imposed by the development of multi-detectors. A special attention has been devoted to ergonomic aspects and configuration possibilities. (authors)

  8. 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

  9. 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

  10. Testing the spatial neutrality of the REMI net migration equation

    International Nuclear Information System (INIS)

    Barr, C.F.; Perrigo, T.A.; Daneshvary, N.; Rickman, D.S.

    1994-01-01

    The U.S. Department of Energy (DOE), Yucca Mountain Site Characterization Project Office (YMPO) is conducting socioeconomic studies in the State of Nevada in accordance with the Nuclear Waste Policy Act of 1982, as amended. The main purpose of the socioeconomic program is to avoid or minimize adverse socioeconomic impacts of the Yucca Mountain Site Characterization Project (YMP) on local communities, counties, and the state of Nevada. This objective is being met by collecting data that can be used by the DOE and affected units of local government to monitor economic and demographic variables and forecast changes that may occur as a direct result of the YMP. One of the tools being used to develop population and employment forecasts in Clark, Lincoln, and Nye counties in Nevada is Regional Economic Modeling Inc.'s (REMI) Economic-Demographic Forecasting and Simulation (EDFS) model. The REMI model is widely used in applied economics for: forecasting and planning; economic development; transportation; energy and natural resources; taxation, budget, and welfare; United States policies; and environmental policies. This model was chosen by the DOE because it is a dynamic econometric model based on accepted economic theory and principles, and because of its favorable rating compared to other available models. The dynamic nature of the model offers improvements in forecasting capabilities over input-output models. Because the DOE is making extensive use of the REMI model, it is necessary to evaluate the model's forecasting performance. This study is an empirical test of the restrictions in the REMI model's net migration equation. The REMI model pools the data across regions to estimate net migration into each region. For this study we will examine Clark County net migration. We hypothesize that due to the differences among regions (such as distance, and geographic and cultural features specific to each region), pooling the data across regions may not be appropriate

  11. Angiotensin Converting Enzyme Regulates Cell Proliferation and Migration.

    Directory of Open Access Journals (Sweden)

    Erika Costa de Alvarenga

    Full Text Available The angiotensin-I converting enzyme (ACE plays a central role in the renin-angiotensin system, acting by converting the hormone angiotensin-I to the active peptide angiotensin-II (Ang-II. More recently, ACE was shown to act as a receptor for Ang-II, and its expression level was demonstrated to be higher in melanoma cells compared to their normal counterparts. However, the function that ACE plays as an Ang-II receptor in melanoma cells has not been defined yet.Therefore, our aim was to examine the role of ACE in tumor cell proliferation and migration.We found that upon binding to ACE, Ang-II internalizes with a faster onset compared to the binding of Ang-II to its classical AT1 receptor. We also found that the complex Ang-II/ACE translocates to the nucleus, through a clathrin-mediated process, triggering a transient nuclear Ca2+ signal. In silico studies revealed a possible interaction site between ACE and phospholipase C (PLC, and experimental results in CHO cells, demonstrated that the β3 isoform of PLC is the one involved in the Ca2+ signals induced by Ang-II/ACE interaction. Further studies in melanoma cells (TM-5 showed that Ang-II induced cell proliferation through ACE activation, an event that could be inhibited either by ACE inhibitor (Lisinopril or by the silencing of ACE. In addition, we found that stimulation of ACE by Ang-II caused the melanoma cells to migrate, at least in part due to decreased vinculin expression, a focal adhesion structural protein.ACE activation regulates melanoma cell proliferation and migration.

  12. Visualizing Human Migration Trhough Space and Time

    Science.gov (United States)

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

    2015-07-01

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

  13. Renewable Resources, Environmental Pollution, and International Migration

    OpenAIRE

    KENJI KONDO

    2013-01-01

    We develop a two-country model with two industries: the smokestack manufacturing industry, which generates pollution, and the transboundary renewable resource industry. With no trade, migration occurs from the foreign country, with lower manufacturing productivity, to the home country. If the gap in pollution abatement technology, which is superior in the home country, dominates the productivity gap, both countries gain from migration. Under a free trade equilibrium, we also show that if the ...

  14. Cesium migration experiments in different media

    International Nuclear Information System (INIS)

    Tello, C.C.O. de

    1992-01-01

    The environmental impact caused by the radioactive waste disposal depends on many factors, mainly on the release pathways of the radionuclides from the waste product to the environment. The migration of the radioelements through the different barriers, which compose the disposal system, is considered the main via for this release. This paper describes the experiments carried out to improve the cemented waste quality, as well to assess the cesium migration in different media. (author)

  15. A Customizable Chamber for Measuring Cell Migration.

    Science.gov (United States)

    Chowdhury, Aniqa N; Vo, Huu Tri; Olang, Sharon; Mappus, Elliott; Peterson, Brian; Hlavac, Nora; Harvey, Tyler; Dean, Delphine

    2017-03-12

    Cell migration is a vital part of immune responses, growth, and wound healing. Cell migration is a complex process that involves interactions between cells, the extracellular matrix, and soluble and non-soluble chemical factors (e.g., chemoattractants). Standard methods for measuring the migration of cells, such as the Boyden chamber assay, work by counting cells on either side of a divider. These techniques are easy to use; however, they offer little geometric modification for different applications. In contrast, microfluidic devices can be used to observe cell migration with customizable concentration gradients of soluble factors 1 , 2 . However, methods for making microfluidics based assays can be difficult to learn. Here, we describe an easy method for creating cell culture chambers to measure cell migration in response to chemical concentration gradients. Our cell migration chamber method can create different linear concentration gradients in order to study cell migration for a variety of applications. This method is relatively easy to use and is typically performed by undergraduate students. The microchannel chamber was created by placing an acrylic insert in the shape of the final microchannel chamber well into a Petri dish. After this, poly(dimethylsiloxane) (PDMS) was poured on top of the insert. The PDMS was allowed to harden and then the insert was removed. This allowed for the creation of wells in any desired shape or size. Cells may be subsequently added to the microchannel chamber, and soluble agents can be added to one of the wells by soaking an agarose block in the desired agent. The agarose block is added to one of the wells, and time-lapse images can be taken of the microchannel chamber in order to quantify cell migration. Variations to this method can be made for a given application, making this method highly customizable.

  16. 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.

  17. 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.

  18. Migration, income redistribution, and international capital mobility

    OpenAIRE

    Meckl, Jürgen

    1994-01-01

    This paper studies income-redistribution effects from labor migration in a small open economy under alternative assumptions on the international mobility of capital. Our principal result is that induced international capital flows dampen or may even reverse redistribution effects. However, as long as the location of capital is unaffected by migration redistribntion effects may be greater if some of the capital is foreign owned, depending on whether labor and capital are friends or enemies. On...

  19. Does Migration Influence Regional Growth in Romania?

    OpenAIRE

    Bunea Daniela

    2011-01-01

    In the European framework, regional convergence is crucial in ensuring European integration. “Sigma-convergence” deals with how the distribution of national output across economies evolves over time whereas “beta-convergence” deals with the mobility of this output within the same distribution. Migration is one important mechanism in generating convergence. In Romania, during the last few years, the main results point out at an income divergence trend with no migration influence. This irreleva...

  20. Multicore Considerations for Legacy Flight Software Migration

    Science.gov (United States)

    Vines, Kenneth; Day, Len

    2013-01-01

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

  1. 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 ...

  2. 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.

  3. Student Migration Potential: The Case of Bulgaria

    OpenAIRE

    Valentina Makni

    2011-01-01

    Transnational student mobility is a major factor, which plays an ambiguous role in the dynamic process of international highly skilled migration. In this paper we try to attempt an approximate profile of the potential migrant student in Bulgaria, according to the migration incentives, intentions and expectations of highly educated young people from six reputable universities in the country. For this purpose a sample study is applied based on binary logistic regression analysis. Some of the co...

  4. Irregular Migration in Jordan, 1995-2007

    OpenAIRE

    AROURI, Fathi A.

    2008-01-01

    Euro-Mediterranean Consortium for Applied Research on International Migration (CARIM) This paper tackles the question of irregular migration in Jordan through its four main aspects. The first concerns irregular labour migrants and has been approached by using figures showing the socio-economic profile of non Jordanians working in Jordan and, additionally, unemployment in Jordan. This is done by assuming close similarities between legal and irregular labour migrants. The second is an attemp...

  5. Migration, Immigration, and Community: A Commentary

    OpenAIRE

    Dan Landis

    2011-01-01

    This paper comments on six papers that deal with aspects of migration in different countries. While each of the papers provides important and interesting facets of the issue of migration and are very welcome, they also use different methodologies, sometimes within the same article, as might be expected in a rather new field. Generally, this commentary focuses on methodological issues since those will lie at the heart of any assessment of the credibility and usefulness of the various findings....

  6. Technetium migration in natural clays

    International Nuclear Information System (INIS)

    Luebke, Maria

    2015-01-01

    The present work was performed within the joint research project ''Retention of repository relevant radionuclides in argillaceous rocks and saline systems'' (contract no.: 02E10981), funded by the Federal Ministry for Economic Affairs and Energy (BMWi). The aim was to obtain first insights into the interaction of the long-lived fission product technetium and natural clay with regard to a repository for high-level nuclear waste. For this purpose Opalinus Clay from Mont Terri (northern Switzerland) was used as a reference material. The nuclide technetium-99 will contribute to the radiotoxicity of spent nuclear fuel for more than thousand years due to its long half-live. In case of a leakage of the storage vessels, the geochemistry of technetium is determined by its oxidation state, at which only the oxidation states +IV and +VII are relevant. Because of the high solubility and low affinity to sorption on surfaces of minerals, Tc(VII) is considered to be very mobile and thus the most hazardous species. The focuses of this study therefore are diffusion experiments with this mobile species and investigations of the effect of ferrous iron on the mobility and speciation of technetium.rnThe interaction of technetium and Opalinus Clay was studied in sorption and diffusion experiments varying several parameters (pH value, addition of reducing agents, effect of oxygen, diffusion pathways). In the course of this study spatially resolved investigations of the speciation have been performed on Opalinus Clay thin sections and bore cores for the first time. In addition to the speciation, further information regarding elemental distributions and crystalline phases near technetium enrichments were obtained. Supplementary investigations of powder samples allowed determining the molecular structure of technetium on the clay surface.rnBoth the combination of sorption experiments with spectroscopic investigations and the diffusion experiment exhibit a reduction of Tc

  7. Investigations and technical reviews on the reliability of prediction for migration behavior of radionuclides (H15)

    International Nuclear Information System (INIS)

    Tachikawa, Hirokazu

    2004-02-01

    The research plan of the validation on effects of colloids and organic materials drawn up by the Japan Nuclear Fuel Cycle Development Institute and its' research outcome were reviewed comprehensively by an expert committee established in the Nuclear Safety Research Association. Additionally, experimental investigations for the migration behavior of actinide elements and fission products in engineering barrier and natural barrier medias, and for solution chemistry of them were carried out and discussed by the committee, in order to enhance the reliability of prediction for migration behavior of radionuclides. The subjects investigated by the expert committee are as follows: (1) Research on solubility products of An(III) hydroxide. (2) Diffusion and electromigration behavior of plutonium in buffer material. (3) Analysis of the nuclide solubility in compacted bentonite. (4) Survey of the actual contamination by alpha emitters in steel materials. (author)

  8. Interaction of groundwater and fresh basalt fissure surfaces and its effect on the migration of actinides

    International Nuclear Information System (INIS)

    Vandegrift, G.F.; Bowers, D.L.; Gerding, T.J.; Fried, S.M.; Wilbur, C.K.; Seitz, M.G.

    1983-01-01

    Experiments are being performed at Argonne National Laboratory (ANL): (1) to identify interactions of radionuclides and repository components that effect nuclide migration, and (2) to assess changes in nuclide migration caused by modifications expected upon aging of the waste, clay backfill, and rock. The experiments are conducted with radioactive borosilicate glass, bentonite and mechanically fissured basalt rock in flowing water analogous to their configuration in a breach of a nuclear waste repository. Changes undergone by the groundwater as it passed through the fissure include: (1) drop in pH from 10 to 8, (2) loss of suspended particulate, and (3) loss of dissolved/suspended U, Np, and Pu. These effects, also studied as functions of radiation dose and of laboratory aging of the repository components, are related to the predicted long-term performance of a nuclear waste repository

  9. Migration: a core public health ethics issue.

    Science.gov (United States)

    Wild, V; Dawson, A

    2018-05-01

    In this article, we outline the link between migration, public health and ethics. Discussing relevant arguments about migration from the perspective of public health and public health ethics. Critical review of theories and frameworks, case-based analysis and systematic identification and discussion of challenges. Migration is a core issue of public health ethics and must take a case-based approach: seeking to identify the specific ethical dimensions and vulnerabilities in each particular context. Public health as a practice, built upon the core value of justice, requires the protection and promotion of migrants' well-being (even if this produces tension with immigration services). Ethical analysis should take all phases of migration into account: before, during and after transit. We argue that migration policies, at least as they relate to migrants' well-being, should be founded upon a shared humanity, respect for human rights and on the idea that effective public health cannot and should not be confined within the borders and to the citizens of any host country. We make the case for migration to be seen as a core issue of public health ethics. Copyright © 2018 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  10. Spring Bird Migration Phenology in Eilat, Israel

    Directory of Open Access Journals (Sweden)

    Reuven Yosef

    2009-12-01

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

  11. Entropy measures of collective cell migration

    Science.gov (United States)

    Whitby, Ariadne; Parrinello, Simona; Faisal, Aldo

    2015-03-01

    Collective cell migration is a critical process during tissue formation and repair. To this end there is a need to develop tools to quantitatively measure the dynamics of collective cell migration obtained from microscopy data. Drawing on statistical physics we use entropy of velocity fields derived from dense optic flow to quantitatively measure collective migration. Using peripheral nerve repair after injury as experimental system, we study how Schwann cells, guided by fibroblasts, migrate in cord-like structures across the cut, paving a highway for neurons. This process of emergence of organised behaviour is key for successful repair, yet the emergence of leader cells and transition from a random to ordered state is not understood. We find fibroblasts induce correlated directionality in migrating Schwann cells as measured by a decrease in the entropy of motion vector. We show our method is robust with respect to image resolution in time and space, giving a principled assessment of how various molecular mechanisms affect macroscopic features of collective cell migration. Finally, the generality of our method allows us to process both simulated cell movement and microscopic data, enabling principled fitting and comparison of in silico to in vitro. ICCS, Imperial College London & MRC Clinical Sciences Centre.

  12. 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

  13. The gravity model of labor migration behavior

    Science.gov (United States)

    Alexandr, Tarasyev; Alexandr, Tarasyev

    2017-07-01

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

  14. Physicians' Migration: Perceptions of Pakistani Medical Students.

    Science.gov (United States)

    Hossain, Nazli; Shah, Nusrat; Shah, Tahira; Lateef, Sidra Binte

    2016-08-01

    To study the perceptions of medical students about factors responsible for physicians'migration. Cross-sectional survey. Dow Medical College and Civil Hospital, Karachi, from April to May 2015. Aself-administered structured questionnaire was used including demographic details, attitudes about push and pull factors of migration, and reasons for migrating or not migrating abroad. Final year students and interns were included. Likert scale from 1 to 4 (1=strongly disagree to 4=strongly agree) was used to assess attitudes. Data was analyzed by SPSS version 16. Atotal of 240 medical students, mostly females (n=181, 75%) (60% final year and 40% interns), participated in the study. Majority wished to go abroad (n=127; 54%) with United States being the favourite destination (n=80; 66.1%) and internal medicine fields being the preferred choice for specialization (n=126; 54%). The major pull factors were better quality of postgraduate education abroad (n=110; 48.2%) and economic prospects (80; 35.2%); while the push factors were a weak healthcare system (n=219; 94.3%), inadequate salary structure (n=205; 88.3%), insecurity (n=219; 93.9%) and increasing religious intolerance in Pakistan (n=183; 78.5%). This survey highlights the continuing trend of physician migration from Pakistan owing to an interplay of various push and pull factors. Majority of our medical students wish to migrate, mainly due to low salaries, poor job structure, and insecurity. Urgent interventions are required to reverse this trend of medical brain-drain.

  15. Integrating meteorology into research on migration.

    Science.gov (United States)

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

    2010-09-01

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

  16. People's Republic of China's Contemporary Migration Processes

    Directory of Open Access Journals (Sweden)

    Martina Bofulin

    2014-12-01

    Full Text Available The last three decades of significant political, economic and social transformations in the People’s Republic of China have had a profound impact on the Chinese society. The article addresses selected topics of Chinese migration that give a more nuanced understanding of migration processes and their contextualization within the contemporary Chinese society: the internal migration, emigration from China and international immigration to China. Migration from rural area towards urban eastern coast is one of the largest spatial movements in the human history, as well as a key component of the economic rise and subsequent social change. Emigration from China has, despite its relatively small volume, profoundly transformed local places of origin, a process that is not independent from the current international geopolitical situation. Immigration of international migrants to China is a relatively new phenomenon that puts the country on the map of migration destination countries for the first time in sixty years. The author concludes that the prevalent research perspectives on Chinese migration offer only a limited insight and suggests some possible alternative ways of analyzing this phenomenon.

  17. 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.

  18. Nuclear fuels

    International Nuclear Information System (INIS)

    Beauvy, M.; Berthoud, G.; Defranceschi, M.; Ducros, G.; Guerin, Y.; Limoge, Y.; Madic, Ch.; Santarini, G.; Seiler, J.M.; Sollogoub, P.; Vernaz, E.; Guillet, J.L.; Ballagny, A.; Bechade, J.L.; Bonin, B.; Brachet, J.Ch.; Delpech, M.; Dubois, S.; Ferry, C.; Freyss, M.; Gilbon, D.; Grouiller, J.P.; Iracane, D.; Lansiart, S.; Lemoine, P.; Lenain, R.; Marsault, Ph.; Michel, B.; Noirot, J.; Parrat, D.; Pelletier, M.; Perrais, Ch.; Phelip, M.; Pillon, S.; Poinssot, Ch.; Vallory, J.; Valot, C.; Pradel, Ph.; Bonin, B.; Bouquin, B.; Dozol, M.; Lecomte, M.; Vallee, A.; Bazile, F.; Parisot, J.F.; Finot, P.; Roberts, J.F.

    2009-01-01

    Fuel is one of the essential components in a reactor. It is within that fuel that nuclear reactions take place, i.e. fission of heavy atoms, uranium and plutonium. Fuel is at the core of the reactor, but equally at the core of the nuclear system as a whole. Fuel design and properties influence reactor behavior, performance, and safety. Even though it only accounts for a small part of the cost per kilowatt-hour of power provided by current nuclear power plants, good utilization of fuel is a major economic issue. Major advances have yet to be achieved, to ensure longer in-reactor dwell-time, thus enabling fuel to yield more energy; and improve ruggedness. Aside from economics, and safety, such strategic issues as use of plutonium, conservation of resources, and nuclear waste management have to be addressed, and true technological challenges arise. This Monograph surveys current knowledge regarding in-reactor behavior, operating limits, and avenues for R and D. It also provides illustrations of ongoing research work, setting out a few noteworthy results recently achieved. Content: 1 - Introduction; 2 - Water reactor fuel: What are the features of water reactor fuel? 9 (What is the purpose of a nuclear fuel?, Ceramic fuel, Fuel rods, PWR fuel assemblies, BWR fuel assemblies); Fabrication of water reactor fuels (Fabrication of UO 2 pellets, Fabrication of MOX (mixed uranium-plutonium oxide) pellets, Fabrication of claddings); In-reactor behavior of UO 2 and MOX fuels (Irradiation conditions during nominal operation, Heat generation, and removal, The processes involved at the start of irradiation, Fission gas behavior, Microstructural changes); Water reactor fuel behavior in loss of tightness conditions (Cladding, the first containment barrier, Causes of failure, Consequences of a failure); Microscopic morphology of fuel ceramic and its evolution under irradiation; Migration and localization of fission products in UOX and MOX matrices (The ceramic under irradiation

  19. Nuclear fuels

    Energy Technology Data Exchange (ETDEWEB)

    Beauvy, M.; Berthoud, G.; Defranceschi, M.; Ducros, G.; Guerin, Y.; Limoge, Y.; Madic, Ch.; Santarini, G.; Seiler, J.M.; Sollogoub, P.; Vernaz, E.; Guillet, J.L.; Ballagny, A.; Bechade, J.L.; Bonin, B.; Brachet, J.Ch.; Delpech, M.; Dubois, S.; Ferry, C.; Freyss, M.; Gilbon, D.; Grouiller, J.P.; Iracane, D.; Lansiart, S.; Lemoine, P.; Lenain, R.; Marsault, Ph.; Michel, B.; Noirot, J.; Parrat, D.; Pelletier, M.; Perrais, Ch.; Phelip, M.; Pillon, S.; Poinssot, Ch.; Vallory, J.; Valot, C.; Pradel, Ph.; Bonin, B.; Bouquin, B.; Dozol, M.; Lecomte, M.; Vallee, A.; Bazile, F.; Parisot, J.F.; Finot, P.; Roberts, J.F

    2009-07-01

    Fuel is one of the essential components in a reactor. It is within that fuel that nuclear reactions take place, i.e. fission of heavy atoms, uranium and plutonium. Fuel is at the core of the reactor, but equally at the core of the nuclear system as a whole. Fuel design and properties influence reactor behavior, performance, and safety. Even though it only accounts for a small part of the cost per kilowatt-hour of power provided by current nuclear power plants, good utilization of fuel is a major economic issue. Major advances have yet to be achieved, to ensure longer in-reactor dwell-time, thus enabling fuel to yield more energy; and improve ruggedness. Aside from economics, and safety, such strategic issues as use of plutonium, conservation of resources, and nuclear waste management have to be addressed, and true technological challenges arise. This Monograph surveys current knowledge regarding in-reactor behavior, operating limits, and avenues for R and D. It also provides illustrations of ongoing research work, setting out a few noteworthy results recently achieved. Content: 1 - Introduction; 2 - Water reactor fuel: What are the features of water reactor fuel? 9 (What is the purpose of a nuclear fuel?, Ceramic fuel, Fuel rods, PWR fuel assemblies, BWR fuel assemblies); Fabrication of water reactor fuels (Fabrication of UO{sub 2} pellets, Fabrication of MOX (mixed uranium-plutonium oxide) pellets, Fabrication of claddings); In-reactor behavior of UO{sub 2} and MOX fuels (Irradiation conditions during nominal operation, Heat generation, and removal, The processes involved at the start of irradiation, Fission gas behavior, Microstructural changes); Water reactor fuel behavior in loss of tightness conditions (Cladding, the first containment barrier, Causes of failure, Consequences of a failure); Microscopic morphology of fuel ceramic and its evolution under irradiation; Migration and localization of fission products in UOX and MOX matrices (The ceramic under

  20. Migration of bacteria in compacted clay-based material

    International Nuclear Information System (INIS)

    Stroes-Gascoyne, S.; Lucht, L.M.; Oscarson, D.W.; Dixon, D.A.; Hume, H.B.; Miller, S.H.

    1997-11-01

    Buffer (a mixture of 50 wt.% Na-bentonite and 50 wt.% silica sand compacted to a dry density of about 1.68 g/cm 3 ) would surround waste containers in a Canadian nuclear fuel waste disposal vault. The initial heat and radiation output from these containers would likely prevent significant microbial activity at or near container surfaces for some time after disposal, thereby limiting effects such as microbially-influenced corrosion. Microbial repopulation of buffer as conditions improve with time may not occur because of its small pores. Experiments with irradiated buffer plugs (2.2 cm in diameter and 5-cm long; at dry densities of 1.68 and 1.80 g/cm 3 ) were performed to assess the ability of microbes to migrate in buffer. Viable bacteria (Pseudomonas stutzeri), in a suitable growth medium, were brought in contact with one end of the plugs. After 2, 4, 8, 16 and 20 weeks, the plugs were sectioned and tested for moisture content and viable bacteria. Results showed that the plugs were slowly wetting and that moisture levels were sufficient to sustain microbes. No evidence of P. stutzeri was found, however, in all but the first 0.5 cm of the plugs (smallest distance sampled) over a 20-week period. The results suggest that microbial migration in buffer is limited or even completely prevented because of its relatively small pores. (author)