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Sample records for evaluating element migration

  1. Evaluation of chemical elements migration from food packaging plastics into food

    International Nuclear Information System (INIS)

    Kamiya, Adriana M.; Fulfaro, Roberto; Saiki, Mitiko

    2000-01-01

    This work presents results of As, Cd, Co, Cr, Sb, Se, Sn, and Zn obtained in the analysis of plastics from food packing materials by instrumental neutron activation analysis. The radiometric method was also applied to evaluate the migration of Co and Sb from the plastic into the food simulant. The possible sources of the toxic elements in plastic materials and the advantages of radiometric method in the migration evaluation are discussed. (author)

  2. 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)

  3. 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

  4. A study of elemental migration from poly(ethylene terephthalate) of food packagings to simulated solutions by radiometric method

    International Nuclear Information System (INIS)

    Soares, Eufemia Paez; Saki, Mitiko; Silva, Leonardo G.A.

    2007-01-01

    Brazilian plastic production for food packagings, in recent years, has grown in the same proportion as food consumption. Considering that the plastic manufacturing involves catalytic processes and the use of additives, when the foods are in direct contact with these materials, the components present in plastics may migrate to the food. The Brazilian Health Surveillance Agency (ANVISA) has established boundary-values of migrants as well as procedures to evaluate migration of elements and substances from plastic packaging to food. In this study elemental composition of poly (ethylene terephthalate) - PET - packaging and results of elemental migration were obtained. Instrumental Neutron Activation Analysis (INAA) was used to determine elemental concentrations in PET packagings and the radiometric method was applied for elemental migration determination. This radiometric method consisted of irradiating the PET samples with neutrons, followed by migration exposition and radioactivity measurement in food-simulated solution. Experimental conditions used for migration were 10 days exposure period at 40 deg C. Migration was evaluated for soft drink, juice and water PET packaging. The analytical results indicated that PET packagings contain Co and Sb and those elements are transferred to the simulated solutions. However, these migration results were lower than the maximum tolerance values established by ANVISA. The migration detection limits also indicated high sensitivity of the radiometric method. (author)

  5. Basics elements for modelling the dynamics of cell migration in cell culture

    International Nuclear Information System (INIS)

    FarIas, Ro; Vidal, Cs; Rapacioli, M; Flores, V

    2007-01-01

    This paper introduces some basic elements for modelling the dynamics of cell migration activity over a bi-dimensional substratum. A square matrix, representing the substratum, is implemented in order to generate virtual cells with an initial random uniform distribution, with the ability to freely move within the matrix and to interact with each others by mean of adhesive forces. Two different conditions were examined: A) cells can freely move and after contacting with another cell they both completely inhibit their migration; B) cells that come into contact have the ability to rotate respect to each other without losing their contacts and retaining the ability to move together but at a slower rate, being the decrease in the rate of movement proportional to the number of contacting cells. The dynamics of the migration process in these two conditions was evaluated by recording the evolution of several parameters as a function of time. Minor modifications in some parameters (mobility, intensity of cell-cell and cell-substratum adhesiveness) significantly change the dynamics and the final result of the virtual migrating cells

  6. Radiochemical approaches to the migration of elements from a radwaste repository

    International Nuclear Information System (INIS)

    Guillaumont, R.

    1993-01-01

    Underground high-level or intermediary-level alpha radwaste repositories will contain tons to hundreds of tons of anthropogenic elements. It is predicted that the release of the elements into the far field will be mainly dependent upon the 'solubilities', sums of the concentrations of soluble species and colloidal/pseudo colloidal forms, of expected near field compounds. On the other hand, safety assessments, based on computation models of migration, show that elements in the discharged water into the biosphere will be at tracer level, or at least, at trace levels. Kinetic and thermodynamic aspects of the processes in which elements will be involved during their migration are discussed together with the change in their concentrations, over several orders of magnitude. It is shown that special attention must be given to predict the behaviour of the elements in the far field from what we know from classical chemistry, and that more experimental data must be obtained to improve the models. (author). 31 refs., 5 figs., 4 tabs

  7. Trace elements in migrating high-temperature fluids: Effects of diffusive exchange with the adjoining solid

    Science.gov (United States)

    Kenyon, Patricia M.

    1993-01-01

    Trace element concentrations and isotopic ratios are frequently used to study the behavior of high-temperature fluids in both metamorphic and igneous systems. Many theoretical formulations of the effects of fluid migration on trace elements have assumed instantaneous reequilibration between the migrating fluid and the solid material through which it is passing. This paper investigates the additional effects which arise when equilibration is not instantaneous due to a limited rate of diffusion in the solid, using an analytical steady state solution to a set of partial differential equations describing the exchange of trace elements between the fluid and the solid during the migration of the fluid.

  8. Application of INAA in monitoring vertical migration of elements in weathering zone

    International Nuclear Information System (INIS)

    Frana, J.; Mastalka, A.; Henes, J.

    1983-01-01

    The vertical migration of elements is studied in two types of Czechoslovak soils formed on loess. The INAA method is used to determine the total value of ca 40 elements in soils. Processed are relative errors of determination and the concentrations of elements to depths of 150 cm. Tables show the distribution of elements of rare earths according to genetic horizons, graphically presented is the vertical distribution of elements with concentrations exceeding 0.1 weight %. Soil enrichment or depletion with trace elements as compared with bedrock is shown on the examples of Co, Mn and Zn. (author)

  9. Hepatic element concentrations of lesser scaup (aythya affinis) during spring migration in the upper midwest

    Science.gov (United States)

    Pillatzki, A.E.; Neiger, R.D.; Chipps, S.R.; Higgins, K.F.; Thiex, N.; Afton, A.D.

    2011-01-01

    High concentrations of some hepatic elements might be contributing to the decline of the continental lesser scaup (Aythya affinis) population. We evaluated hepatic element concentrations of male and female lesser scaup collected from the upper Midwest (Iowa, Minnesota, North Dakota, and South Dakota) during the 2003 and 2004 spring migrations. We measured concentrations of 24 elements in livers of 117 lesser scaup. We found that only selenium concentrations were at levels (>3.0 ??g/g wet weight [ww)]) proposed to adversely affect reproduction. Approximately 49% of females (n = 61) had individual hepatic concentrations >3.0 ??g/g ww selenium (Se). Our observed hepatic concentration of Se was similar to that reported in lesser scaup collected from the mid-continental United States but less than Se concentrations reported from the Great Lakes region. We found that the liver cadmium (Cd) concentration for males was significantly higher than that for females. Gender differences in hepatic Cd concentrations have not been previously reported for lesser scaup, but Cd is known to have negative impacts on male reproduction. Our results indicate that lesser scaup migrating through the upper Midwest in spring have elevated Se levels and that males carry a significantly greater Cd burden than females. Moreover, elemental concentrations might be high enough to affect reproduction in both male and female lesser scaup, but controlled laboratory studies are needed to adequately assess the effects of Se and Cd on lesser scaup reproduction. ?? 2010 Springer Science+Business Media, LLC.

  10. Migration of actinide elements in representative US soils

    International Nuclear Information System (INIS)

    Sheppard, J.C.; Campbell, M.J.; Kittrick, J.A.; Hardt, T.L.

    1981-01-01

    Diffusion data indicate the Am, Cm, and Np migrate 1.2, 0.8, and 26 centimeters, respectively, in a thousand years. Thus, excluding mass transport by moving water or wind, actinide elements, such as Cm, Am, and Np that find their way to the soil-squatic environment are relatively immobile. Measured diffusion coefficients, corrected for distribution between the aqueous and soil phases, tortuosity, negative absorption, and relative fluidity are in reasonable agreement with aqueous diffusion coefficients. However, agreement depends strongly on measurement method used to determine distribution ratios

  11. Migration of uranium and associated elements in statigraphic section of the Digomi-Saburtalinsk depression

    International Nuclear Information System (INIS)

    Vardzelashvili, N.S.; Areshidze, G.G.; Khutsaidze, A.L.

    1982-01-01

    Rock samples from different levels of stratigraphic section of the Digomi-Saburtatinsk depresion and underground thermal waters of the well for investigation into reguliarities of distribution, migration and deposition of uranium and associated elements were studied. Absence of correlation between the content elements under investigation and the depth of rock occurrence, their qranulometric and substantial composition was established. Concentration factors for Pb, Co, Cr over the whole section are more than one and for Ni, Mn, 6a, Ti, Zn, U, Th are less than one Th/U ratios enable to propose, that U in the hypergenesis zone is removed simultaneously with hydrophilic elements. Water-bearing complex of thermal waters occurs at 1200-3100 m in depth. Thermal waters are weakly mineralized alkalihydrosulphuric (oxygen-free) with low factor of water migration of U (0.001); uranium associated elements are absent. The present-day chemical conditions point to the fact, that U supply in rocks with thermal waters didn't take place

  12. A study of long-term (103-104Yr) elemental migration in saturated clays and sediments

    International Nuclear Information System (INIS)

    Mac Kenzie, A.B.; Scott, R.D.; Ridgway, I.M.; Mc Kinley, I.G.; West, J.M.

    1986-01-01

    This report presents the results of a project to investigate the use of elemental profiles in Scottisch sediments resulting from the Flandrian marine transgression as a natural analogue of radionuclide migration through argillaceous material. The work was carried out within Research Area no. 5 of the CEC project MIRAGE ''Natural Geological Migration Systems''

  13. Assessment of chemical element migration in soil-plant complex of Urov endemic localities of East Transbaikalia

    Science.gov (United States)

    Vadim V., Ermakov; Valentina, Danilova; Sabsbakhor, Khushvakhtova; Aklexander, Degtyarev; Sergey, Tyutikov; Victor, Berezkin; Elena, Karpova

    2014-05-01

    The comparative evaluation of the levels of biologically active chemical elements and their migration in the soil-plant complex of two Urov endemic locations in East Transbaikalia (Zolinsky and Uryumkansky) and background areas (Western Baikal region and the western area of the Trans-Baikal region) was conducted. The predominant soil-forming rocks in East Transbaikalia are weathering products of Proterozoic carbonated granitoids PR2. The surface rocks consist from granite, granodiorite, diorite quartz diorite, gabbro, norite, gabbro-norite and other. Soils - mountain and cryogenic meadow forests, mountain permafrost taiga podzolised, meadow alluvial, peaty meadow [2]. The paludification of narrow valleys and thermokarst phenomena are typical in Urov endemic localities. It reflects on the spotted of soil and differentiation of chemical composition of soils and plants. Most of the chemical elements in soils were determined by means of X-ray fluorescence, and trace elements in soils and plants - by atomic absorption spectrometry. The selenium content was measured by spectrofluorimetric method [3]. The research processed by methods of variation statistics. It was found that the soils of two locations of the Urov subregion of the biosphere were more enriched with iron, barium, calcium, uranium, thorium, phosphorus, and to a lesser extent strontium compared to background soils. The ratio of Ca: P was significantly higher in the soil of background areas, and Ca: Sr, on the contrary, in endemic soils. In assessing the migration of trace elements in soil-plant complex by means of the total content of trace elements and biological absorption coefficient found a marked accumulation by plants manganese, chromium, arsenic and weak plants accumulation of cobalt and nickel. Soil landscape is not much different in content of selenium, but its migration in plants was reduced in places of spread of Urov disease [1]. The concentrators of cadmium (leaves of different species of willow

  14. The validation of a method for determining the migration of trace elements from food packaging materials into food

    International Nuclear Information System (INIS)

    Thompson, D.; Parry, S.J.; Benzing, R.

    1997-01-01

    A new radiotracer method has been developed to measure the migration of trace elements from food contact packaging into four standard food simulants; acetic acid, ethanol, olive oil, deionised water. A sample of material is irradiated in a thermal neutron flux of 10 16 n x m -2 x s -1 to activate the trace elements and produce a range of radionuclides. The samples is then placed in the food simulant and the migration of the radionuclides is monitored by performing γ-ray spectrometry on a sample of the simulant. Any radionuclides measured must be due entirely to the migration of the elements present in the plastic, since the simulant itself is not radioactive. Preliminary studies have shown that detection limits of around 0.2 μg x dm -2 (0.002 mg/kg) can be achieved for antimony in a sample of polyethylene terephthalate. This method can now been extended to measure migration into real foods. This will highlight any differences between the standard simulants currently used and real foods. Since the method only involves irradiation of the packaging material any food matrix can be studied. (author)

  15. Geological occurrence response to trace elemental migration in coal liquefaction based on SPSS: take no. 11 coalbed in Antaibao mine for example

    Science.gov (United States)

    Xia, Xiaohong; Qin, Yong; Yang, Weifeng

    2013-03-01

    Coal liquefaction is an adoptable method to transfer the solid fossil energy into liquid oil in large scale, but the dirty material in which will migrate to different step of liquefaction. The migration rule of some trace elements is response to the react activity of macerals in coal and the geological occurrence of the element nature of itself. In this paper, from the SPSS data correlation analysis and hierarchical clustering dendrogram about the trace elements with macerals respond to coal liquefaction yield, it shows the trace elements in No.11 Antaibao coal seam originated from some of lithophile and sulphophle elements. Correlation coefficient between liquefaction yield of three organic macerals and migration of the elements in liquefaction residue indicated that the lithophile are easy to transfer to residue, while sulphophle are apt to in the liquid products. The activated macerals are response to sulphophle trace elements. The conclusion is useful to the coal blending and environmental effects on coal direct liquefaction.

  16. Migration of components from cork stoppers to food: challenges in determining inorganic elements in food simulants.

    Science.gov (United States)

    Corona, T; Iglesias, M; Anticó, E

    2014-06-18

    The inorganic elements potentially migrating from cork to a food simulant [a hydroalcoholic solution containing 12 and 20% (v/v) ethanol] have been determined by means of inductively coupled plasma (ICP) with atomic emission and mass spectrometric detection. The experimental instrumental conditions were evaluated in depth, taking into account spectroscopic and nonspectroscopic interference caused by the presence of ethanol and other components in the sample. We report concentrations ranging from 4 μg kg(-1) for Cd to 28000 μg kg(-1) for Al in the food simulant (concentrations given in kilograms of cork). The values found for Ba, Mn, Fe, Cu, and Zn have been compared with the guideline values stated in EU Regulation 10/2011. In all cases, cork met the general safety criteria applicable to food contact material. Finally, we have proposed water as an alternative to the hydroalcoholic solution to simplify quantification of the tested elements using ICP techniques.

  17. A Missing Element in Migration Theories.

    Science.gov (United States)

    Massey, Douglas S

    2015-09-01

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

  18. Data base for site specific migration analysis of radioactive elements in repositories

    Energy Technology Data Exchange (ETDEWEB)

    Hadermann, J

    1982-01-01

    Migration analysis is of considerable importance in long-term safety aspects of radioactive waste repositories. The present work gives the data base for a selected part of a comprehensive geosphere transport calculation. We restrict ourselves to a critical evaluation of parameters pertinent to the migration analysis of the /sup 245/Cm chain. This includes the important nuclide /sup 237/Np. With these we are able to perform a site specific calculation for repositories planned in deep geologic formations in Switzerland. It is shown that the granitic basement induces strong time delays in nuclide migration. In contrast to that, the overlaying sedimentary layers cause primarily a dilution of the radionuclide concentrations.

  19. Study of rare earth elements, uranium and thorium migration in rocks from Espinharas uranium deposit, Paraiba - Brazil

    International Nuclear Information System (INIS)

    Conceicao, Cirilo C.S.

    2009-01-01

    The determination of rare earth elements as natural analogue in patterns geologic has grown as a tool for predicting the long-term safety of nuclear disposal in geological formation. Migration of natural radionuclides is one of the most serious problems in the waste deposit from nuclear fuel cycle. Rare earth elements show the same kinetic behavior in rocks as natural radionuclides. This similar property of the analogues allows perform studies and models on the subject of radionuclides migration. The aim of this study was to determine the distribution of rare earth elements in rocks located at Espinharas - Paraiba - Brazil, uranium deposit. In this work are presented the results from the study above the distribution of rare earth elements in function of the degree of mineralized rocks, composition and the conditions of radioactive equilibrium of the uranium and thorium in some fractures on the rocks from radioactive occurrence of Espinharas-Brazil. The results show that there is a correlation of heavy rare earth elements, uranium and Thorium concentrations to oxidation factor of the rocks. However this correlation was not observed for light rare earth elements. It means that heavy rare earth elements follow the natural radionuclides in oxidation process of rocks. The samples were analyzed by ICP-MS, alpha and gamma spectrometry, X-ray diffraction and fluorimetry. (author)

  20. Simulation study ε-Caprolactam monomer and metallic elements migration from irradiated polymeric packaging into food stimulants

    International Nuclear Information System (INIS)

    Rosa, Faena Machado Leite

    2008-01-01

    For decades migration study of chemical compounds from packaging into food, such as metals, residual monomers and additives, is a very important issue, concerning public health and minimize chemical contamination. In this work, it was done irradiations of packagings taken in contact with food simulant, and it was studied this migration through a mathematical model of the diffusion process, compiled in a computational simulation method in order to study the microscopic behavior of migration of metallic elements cadmium, chromium, antimony and cobalt, present in metallic plastics from dairy product packagings, and also the migration of - caprolactam monomer, present in nylon polymeric plastics used for package meat stuffs, to the food simulant acetic acid 3%. The results from simulations of the migration of -caprolactam monomer were compared with experimental results obtained from high resolution gas chromatography (HRGC) measurements, and the simulation of metallic elements migration were compared with the neutron activation analysis measurements (NAA). These experimental results were performed and kindly informed by another research groups, partners in this project. The food packaging system was discretized in one-dimension space and in time and the partial differential equation that defines the diffusive process, the second 'Fick's law', together with an equation of Arrhenius type dealing with the thermal influence, were solved using finite differences. The final step of the resolution was a tridiagonal linear system, solved using the Thomas algorithm. It was studied, and in some cases even foreseen, experimental quantities, like the diffusion coefficient, activation energy and concentration profile of migrant compounds, allowing the understanding of the diffusion process and the quantitative estimate of the migration of such compounds under ionizing radiation influence. Variation on the initial concentration levels (C 0 ) of the monomer inside the packaging

  1. Kink structures induced in nickel-based single crystal superalloys by high-Z element migration

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Fei; Zhang, Jianxin [Key Laboratory for Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Mao, Shengcheng [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China); Jiang, Ying [Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Feng, Qiang [National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Shen, Zhenju; Li, Jixue; Zhang, Ze [Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Han, Xiaodong [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China)

    2015-01-05

    Highlights: • Innovative kink structures generate at the γ/γ′ interfaces in the crept superalloy. • Clusters of heavy elements congregate at the apex of the kinks. • Dislocation core absorbs hexagonal structural high-Z elements. - Abstract: Here, we investigate a new type of kink structure that is found at γ/γ′ interfaces in nickel-based single crystal superalloys. We studied these structures at the atomic and elemental level using aberration corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The core of the dislocation absorbs high-Z elements (i.e., Co and Re) that adopt hexagonal arrangements, and it extrudes elements (i.e., Ni and Al) that adopt face centered cubic (fcc) structures. High-Z elements (i.e., Ta and W) and Cr, which is a low-Z element, are stabilized in body centered cubic (bcc) arrangements; Cr tends to behave like Re. High-Z elements, which migrate and adopt a hexagonal structure, induce kink formation at γ/γ′ interfaces. This process must be analyzed to fully understand the kinetics and dynamics of creep in nickel-based single crystal superalloys.

  2. Can otolith elemental chemistry retrospectively track migrations in fully marine fishes?

    Science.gov (United States)

    Sturrock, A M; Trueman, C N; Darnaude, A M; Hunter, E

    2012-07-01

    scope of migration studies. Among the otolith elements that routinely occur above instrument detection limits, Ba, Mn and Li were deemed the most likely to prove reliable geographic markers in marine species. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  3. Investigation of Vertical Migration of Pollutants through the Unsaturated Zone Using Stable Isotopes and Trace Elements

    International Nuclear Information System (INIS)

    Ahmed, M.A.

    2012-01-01

    Vertical migration of pollutants through unsaturated zone is a complicated process and is affected by a number of factors like type of soil, its chemical properties, or organic matter content, in addition to climatic conditions and biological activity of microorganisms in soil. Soil properties that influence water movement through unsaturated zone are important for determining flow paths, reactions between soil and pollutants and the ultimate destination of these pollutants, and may improve the diagnosis of the potential pollution risk. Three soil cores were sampled to a depth up to 100 cm from cultivated clayey soil, sewage irrigated sandy soil and fertilized sandy soil. The samples were collected at intervals of 5 or 10 cm. The δ 13 C signature of the soil shifted significantly towards that of C 3 -type vegetation in soil cores. The general trend toward heavier 13 C enrichment with depth could be due to isotopic fractionation occurring during decomposition of soil organic matters. Increased δ 15 N with depth in the soil cores suggests that microbial mineralization, denitrification, or volatilization processes caused the enriched δ 15 N signatures. Decreasing nitrogen percent and nitrate values with depth also help support the idea of microbiological processes. The results indicate that concentrations of major and trace elements varied widely among the different soil types and decreased with depths in the studied soil profile. The accumulation pattern for these elements in the soil profiles follows the order: Co < Ni < Mo < Ag < Sr < V < Cu < Cr < Zn < Mn < B < Mg < Al < Fe. The relationships between element concentrations against ph and organic matter contents show antithetical relationships and suggest evidence that these elements arise from anthropogenic input. The results of this study show that there exists risk for the environment due to notable migration of pollutants through the unsaturated zone and that the migrations were also observed to be highly

  4. Evaluation of aluminum migration into foodstuffs from aluminium cookware

    Directory of Open Access Journals (Sweden)

    M Radi

    2014-05-01

    Full Text Available Nowadays, the existence of aluminum in human diet as a food contaminant has attracted the concerns of many researchers. It seems that the cooking pans are common sources of aluminum exposure through foodstuffs in Iran. The aim of this study was to evaluate the migration of aluminum from cooking containers into foodstuffs. For this purpose, solutions with different concentrations of citric acid, sodium chloride, fat, protein and sugar were prepared and migration of aluminum into these solutions was measured using atomic absorption spectrometry. Results showed that salt and citric acid concentrations could enhance aluminum migration; whereas, acid concentration was more effective than salt due to its corrosive effect. The intensity of heat processing and the duration of heat treatment had direct relation with aluminum migration. The aluminum content of cooked foods in aluminum cooking pans was also significantly more than control samples.

  5. Dynamics of Melting and Melt Migration as Inferred from Incompatible Trace Element Abundance in Abyssal Peridotites

    Science.gov (United States)

    Peng, Q.; Liang, Y.

    2008-12-01

    To better understand the melting processes beneath the mid-ocean ridge, we developed a simple model for trace element fractionation during concurrent melting and melt migration in an upwelling steady-state mantle column. Based on petrologic considerations, we divided the upwelling mantle into two regions: a double- lithology upper region where high permeability dunite channels are embedded in a lherzolite/harzburgite matrix, and a single-lithology lower region that consists of partially molten lherzolite. Melt generated in the single lithology region migrates upward through grain-scale diffuse porous flow, whereas melt in the lherzolite/harzburgite matrix in the double-lithology region is allowed to flow both vertically through the overlying matrix and horizontally into its neighboring dunite channels. There are three key dynamic parameters in our model: degree of melting experienced by the single lithology column (Fd), degree of melting experienced by the double lithology column (F), and a dimensionless melt suction rate (R) that measures the accumulated rate of melt extraction from the matrix to the channel relative to the accumulated rate of matrix melting. In terms of trace element fractionation, upwelling and melting in the single lithology column is equivalent to non-modal batch melting (R = 0), whereas melting and melt migration in the double lithology region is equivalent to a nonlinear combination of non-modal batch and fractional melting (0 abyssal peridotite, we showed, with the help of Monte Carlo simulations, that it is difficult to invert for all three dynamic parameters from a set of incompatible trace element data with confidence. However, given Fd, it is quite possible to constrain F and R from incompatible trace element abundances in residual peridotite. As an illustrative example, we used the simple melting model developed in this study and selected REE and Y abundance in diopside from abyssal peridotites to infer their melting and melt migration

  6. Earthquake Clusters and Spatio-temporal Migration of earthquakes in Northeastern Tibetan Plateau: a Finite Element Modeling

    Science.gov (United States)

    Sun, Y.; Luo, G.

    2017-12-01

    Seismicity in a region is usually characterized by earthquake clusters and earthquake migration along its major fault zones. However, we do not fully understand why and how earthquake clusters and spatio-temporal migration of earthquakes occur. The northeastern Tibetan Plateau is a good example for us to investigate these problems. In this study, we construct and use a three-dimensional viscoelastoplastic finite-element model to simulate earthquake cycles and spatio-temporal migration of earthquakes along major fault zones in northeastern Tibetan Plateau. We calculate stress evolution and fault interactions, and explore effects of topographic loading and viscosity of middle-lower crust and upper mantle on model results. Model results show that earthquakes and fault interactions increase Coulomb stress on the neighboring faults or segments, accelerating the future earthquakes in this region. Thus, earthquakes occur sequentially in a short time, leading to regional earthquake clusters. Through long-term evolution, stresses on some seismogenic faults, which are far apart, may almost simultaneously reach the critical state of fault failure, probably also leading to regional earthquake clusters and earthquake migration. Based on our model synthetic seismic catalog and paleoseismic data, we analyze probability of earthquake migration between major faults in northeastern Tibetan Plateau. We find that following the 1920 M 8.5 Haiyuan earthquake and the 1927 M 8.0 Gulang earthquake, the next big event (M≥7) in northeastern Tibetan Plateau would be most likely to occur on the Haiyuan fault.

  7. Separation by sequential chromatography of americium, plutonium and neptunium elements: application to the study of trans-uranian elements migration in a European lacustrine system

    International Nuclear Information System (INIS)

    Michel, H.

    1999-01-01

    The nuclear tests carried out in the atmosphere in the Sixties, the accidents and in particular that to the power station of Chernobyl in 1986, were at the origin of the dispersion of a significant quantity of transuranic elements and fission products. The study of a lake system, such that of the Blelham Tarn in Great Britain, presented in this memory, can bring interesting answers to the problems of management of the environment. The determination of the radionuclides in sediment cores made it possible not only to establish the history of the depositions and consequently the origin of the radionuclides, but also to evaluate the various transfers which took place according to the parameters of the site and the properties of the elements. The studied transuranic elements are plutonium 238, 239-240, americium 241 and neptunium 237. Alpha emitting radionuclides, their determination requires complex radiochemical separations. A method was worked out to successively separate the three radioelements by using a same chromatographic column. Cesium 137 is the studied fission product, its determination is done by direct Gamma spectrometry. Lead 210, natural radionuclide, whose atmospheric flow can be supposed constant. makes it possible to obtain a chronology of the various events. The detailed vertical study of sediment cores showed that the accumulation mode of the studied elements is the same one and that the methods of dating converge. The cesium, more mobile than transuranic elements in the atmosphere, was detected in the 1963 and 1986 fallout whereas an activity out of transuranic elements appears only for the 1963 fallout. The activity of the 1963 cesium fallout is of the same order of magnitude as that of 1986. The calculation of the diffusion coefficients of the elements in the sediments shows an increased migration of cesium compared to transuranic elements. An inventory on the whole of the lake made it possible to note that the atmospheric fallout constitute the

  8. Fine element (F.E.) modelling of hydrogen migration and blister formation in PHWR coolant channels

    International Nuclear Information System (INIS)

    Prasad, P.S.; Dutta, B.K.; Sinha, R.K.; Kushwaha, H.S.; Mahajan, S.C.; Kakodkar, A.

    1995-01-01

    The formation of a cold spot in pressure tube due to its contact with calandria tube of PHWR coolant results in the migration of Hydrogen in pressure tube towards contact zone from its surrounding material. A 3-D finite element code SPARSH is developed to model the hydrogen redistribution and consequent hydride blister formation due to thermal and Hydrogen concentration gradients. In the present paper, the details and performance of this code are presented. (author). 6 refs., 2 figs

  9. GPU-accelerated element-free reverse-time migration with Gauss points partition

    Science.gov (United States)

    Zhou, Zhen; Jia, Xiaofeng; Qiang, Xiaodong

    2018-06-01

    An element-free method (EFM) has been demonstrated successfully in elasticity, heat conduction and fatigue crack growth problems. We present the theory of EFM and its numerical applications in seismic modelling and reverse time migration (RTM). Compared with the finite difference method and the finite element method, the EFM has unique advantages: (1) independence of grids in computation and (2) lower expense and more flexibility (because only the information of the nodes and the boundary of the concerned area is required). However, in EFM, due to improper computation and storage of some large sparse matrices, such as the mass matrix and the stiffness matrix, the method is difficult to apply to seismic modelling and RTM for a large velocity model. To solve the problem of storage and computation efficiency, we propose a concept of Gauss points partition and utilise the graphics processing unit to improve the computational efficiency. We employ the compressed sparse row format to compress the intermediate large sparse matrices and attempt to simplify the operations by solving the linear equations with CULA solver. To improve the computation efficiency further, we introduce the concept of the lumped mass matrix. Numerical experiments indicate that the proposed method is accurate and more efficient than the regular EFM.

  10. Microfluidic platform to evaluate migration of cells from patients with DYT1 dystonia

    NARCIS (Netherlands)

    Nery, Flavia C.; da Hora, Cintia C.; Atai, Nadia A.; Kim, Edward Y.; Hettich, Jasmin; Mempel, Thorsten R.; Breakefield, Xandra O.; Irimia, Daniel

    2014-01-01

    Microfluidic platforms for quantitative evaluation of cell biologic processes allow low cost and time efficient research studies of biological and pathological events, such as monitoring cell migration by real-time imaging. In healthy and disease states, cell migration is crucial in development and

  11. Origin and migration of trace elements in the surface sediments of Majuro Atoll, Marshall Islands.

    Science.gov (United States)

    Ito, Lisa; Omori, Takayuki; Yoneda, Minoru; Yamaguchi, Toru; Kobayashi, Ryuta; Takahashi, Yoshio

    2018-07-01

    The sediments of Majuro Atoll, Marshall Islands, consist of bioclastic materials, including foraminifera and coral debris. The sedimentary depth profiles of elements showed that various elements including zinc (Zn) and copper (Cu) were enriched in the upper layers of the islands of Majuro Atoll. Carbon-14 dating revealed that the sedimentation of the upper layer was completed before 1670 and 542 cal BP in Laura and Calalen, respectively. The enriched elements could be categorized by their origins: (a) terrestrial elements transported as dust (aluminum (Al) and rare earth elements (REEs)); (b) anthropogenic elements (Zn and Cu); and (c) elements supplied by seabirds (phosphorus (P)). From the results of the total amount of Al supplied to sediments for ca. 2000 years, Al in Majuro Atoll was suggested to be airborne origin. The enrichment factors of the elements normalized to Al concentration of continental crust showed that REEs were also transported as dust, while Zn and Cu were mainly of anthropogenic origin. The speciation analysis by X-ray absorption near-edge structure (XANES) showed the presence of Zn-Cu alloys originated from industrial products. It was also revealed that Zn was enriched in the surface due to anthropogenic emission after urbanization on Majuro Atoll and fixed by carbonate and phosphate at the upper layer, which inhibits migration of Zn into the deeper layer and its release to the groundwater and costal water. Hence, the fixation of heavy metals at the surface prevents their exposure to aquatic organisms and residents via fresh groundwater in the island. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Chemical form of transuranic elements in underground environment and its effect on adsorption

    International Nuclear Information System (INIS)

    Tanaka, Tomo

    1990-01-01

    Many of the transuranic elements such as Np, Pu and Am contained in high-level radioactive wastes are highly dangerous to humans and have extremely long lives. Therefore, safety evaluation of them is highly important after their disposal into the ground. Particularly important processes include the migration of these transuranic elements in near and far fields. The migration of a nuclide depends largely on its chemical form in the underground environment. The present report first describes various chemical forms of transuranic elements in underground environments and outlines their migration behaviors. Techniques that have recently become available for determining their chemical forms include photo-acoustic spectroscopy, thermal lensing spectroscopy, laser induced fluorescence, photo-acoustic detection of light scattering, auto-correlation photon spectroscopy, and laser-induced time-resolved spectrofluorometry. Chemical forms of these elements are then discussed focusing on underground environmental conditions, pH-Eh diagram, deposition/dissolution, formation of complex, formation of colloid, and organic complexes. Migration is discussed in relation to ions, insoluble matters, and colloids. (N.K.)

  13. Use of X-ray fluorescence analysis in studying vertical element migration in weathering zone

    International Nuclear Information System (INIS)

    Houdkova, Z.; Hally, J.

    1980-01-01

    The vertical migration of elements was studied in a model area of the Zelivka river basin. The VRS 2 Zeiss GDR analyzer, connected to automatic processor KSR 4 100, were used for the study of concentration variations. Soil samples were taken from bore holes drilled to a depth of the solid bedrock (0 to 6 m). The contents of SiO 2 , Al 2 O 3 , Fe 2 O 3 , K 2 O, CaO, TiO 2 , P 2 O 5 and MnO were determined in concentration ranges from 10 -2 to 10 1 %. The method was tested in comparative measurements against conventional methods of chemical analysis. (author)

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

    Directory of Open Access Journals (Sweden)

    Andrey Anatolievich Sychev

    2016-02-01

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

  15. Evaluating the impacts of migration in the biofilm anode using the model PCBIOFILM

    International Nuclear Information System (INIS)

    Marcus, Andrew K.; Torres, Cesar I.; Rittmann, Bruce E.

    2010-01-01

    Microbial electrochemical cells depend on the reaction by anode-respiring bacteria (ARB). The ARB reaction generates multiple e - and H + , which take diverging paths, creating a charge imbalance. An electric field must migrate ions to restore electrical neutrality. Here, the model proton condition in bioflim (PCBIOFILM) expands for evaluating the impact of migration on the biofilm anode: the expansion makes the proton condition (PC) work in tandem with the electrical-neutrality condition, which is a novel methodological advancement. The analysis with PCBIOFILM examines relevant scenarios of phosphate- and carbonate-buffered biofilm anodes using established parameters. The analysis demonstrates how: (1) the proton condition (PC) maintains electrical neutrality by achieving charge balance; (2) migration influences the biofilm anode more than non-ARB biofilms; (3) migration increases the overall current density, but by less than 15 percent; and (4) PCBIOFILM without migration accurately captures large-scale trends in biofilm anodes.

  16. Evaluation of in vivo labelled dendritic cell migration in cancer patients.

    Science.gov (United States)

    Ridolfi, Ruggero; Riccobon, Angela; Galassi, Riccardo; Giorgetti, Gianluigi; Petrini, Massimiliano; Fiammenghi, Laura; Stefanelli, Monica; Ridolfi, Laura; Moretti, Andrea; Migliori, Giuseppe; Fiorentini, Giuseppe

    2004-07-30

    BACKGROUND: Dendritic Cell (DC) vaccination is a very promising therapeutic strategy in cancer patients. The immunizing ability of DC is critically influenced by their migration activity to lymphatic tissues, where they have the task of priming naïve T-cells. In the present study in vivo DC migration was investigated within the context of a clinical trial of antitumor vaccination. In particular, we compared the migration activity of mature Dendritic Cells (mDC) with that of immature Dendritic Cells (iDC) and also assessed intradermal versus subcutaneous administration. METHODS: DC were labelled with 99mTc-HMPAO or 111In-Oxine, and the presence of labelled DC in regional lymph nodes was evaluated at pre-set times up to a maximum of 72 h after inoculation. Determinations were carried out in 8 patients (7 melanoma and 1 renal cell carcinoma). RESULTS: It was verified that intradermal administration resulted in about a threefold higher migration to lymph nodes than subcutaneous administration, while mDC showed, on average, a six-to eightfold higher migration than iDC. The first DC were detected in lymph nodes 20-60 min after inoculation and the maximum concentration was reached after 48-72 h. CONCLUSIONS: These data obtained in vivo provide preliminary basic information on DC with respect to their antitumor immunization activity. Further research is needed to optimize the therapeutic potential of vaccination with DC.

  17. The use of a Phosphate-Based Migrating Corrosion Inhibitor to Repair Reinforced Concrete Elements Contaminated by Chlorides

    Science.gov (United States)

    Tittarelli, Francesca; Mobili, Alessandra; Bellezze, Tiziano

    2017-08-01

    The use of sodium monofluorophosphate (MFP) was experimented as migrator inhibiting treatment against corrosion of reinforced concrete elements induced by chlorides. The results show that sodium monofluorophosphate, applied by surface impregnation, is able to slow down reinforcement corrosion only for reinforcing steel bars with concrete cover not thicker than 1 cm. This limitation is most probably due to the difficulty, with the type of application adopted, in making MFP to reach concentrations high enough to inhibit the corrosive process at greater depths from the impregnation surface.

  18. Trace element and isotopic effects arising from magma migration beneath mid-ocean ridges

    International Nuclear Information System (INIS)

    Kenyon, P.M.

    1990-01-01

    The trace element concentrations and isotopic ratios in the magma erupted on mid-ocean ridges may differ from those in the source material due to physical effects such as porous flow dispersion, exchange of trace elements between the fluid and solid phases during magma migration, and convective mixing in magma chambers. These differences are in addition to those produced by better known processes such as fractional crystallization and partial melting. The effects of the three former processes are described. It is predicted that magma typically reaches the sub-ridge magma chambers with a spatial heterogeneity only slightly reduced from that of the source material, but with a subdued variation in time. Convective mixing then further reduces the spatial heterogeneity. Application of the results for convective mixing to a recent Fourier analysis of 87 Sr/ 86 Sr variations along the Mid-Atlantic Ridge suggests that the falloff in amplitude of variation observed with decreasing wavelength in the Mid-Atlantic Ridge data cannot be explained by convective mixing in magma chambers. Instead, it is postulated that this falloff is due to the mechanics of the production and/or the solid-state convective mixing of chemical and isotopic heterogeneities in the solid mantle. (orig.)

  19. 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)

  20. Improving TOGAF ADM 9.1 Migration Planning Phase by ITIL V3 Service Transition

    Science.gov (United States)

    Hanum Harani, Nisa; Akhmad Arman, Arry; Maulana Awangga, Rolly

    2018-04-01

    Modification planning of business transformation involving technological utilization required a system of transition and migration planning process. Planning of system migration activity is the most important. The migration process is including complex elements such as business re-engineering, transition scheme mapping, data transformation, application development, individual involvement by computer and trial interaction. TOGAF ADM is the framework and method of enterprise architecture implementation. TOGAF ADM provides a manual refer to the architecture and migration planning. The planning includes an implementation solution, in this case, IT solution, but when the solution becomes an IT operational planning, TOGAF could not handle it. This paper presents a new model framework detail transitions process of integration between TOGAF and ITIL. We evaluated our models in field study inside a private university.

  1. Trace Elements in Basalts From the Siqueiros Fracture Zone: Implications for Melt Migration Models

    Science.gov (United States)

    Pickle, R. C.; Forsyth, D. W.; Saal, A. E.; Nagle, A. N.; Perfit, M. R.

    2008-12-01

    Incompatible trace element (ITE) ratios in MORB from a variety of locations may provide insights into the melt migration process by constraining aggregated melt compositions predicted by mantle melting and flow models. By using actual plate geometries to create a 3-D thermodynamic mantle model, melt volumes and compositions at all depths and locations may be calculated and binned into cubes using the pHMELTS algorithm [Asimow et al., 2004]. These melts can be traced from each cube to the surface assuming several migration models, including a simplified pressure gradient model and one in which melt is guided upwards by a low permeability compacted layer. The ITE ratios of all melts arriving at the surface are summed, averaged, and compared to those of the actual sample compositions from the various MOR locales. The Siqueiros fracture zone at 8° 20' N on the East Pacific Rise (EPR) comprises 4 intra-transform spreading centers (ITSCs) across 140 km of offset between two longer spreading ridges, and is an excellent study region for several reasons. First, an abundance of MORB data is readily available, and the samples retrieved from ITSCs are unlikely to be aggregated in a long-lived magma chamber or affected by along-axis transport, so they represent melts extracted locally from the mantle. Additionally, samples at Siqueiros span a compositional range from depleted to normal MORB within the fracture zone yet have similar isotopic compositions to samples collected from the 9-10° EPR. This minimizes the effect of assuming a uniform source composition in our melting model despite a heterogeneous mantle, allowing us to consistently compare the actual lava composition with that predicted by our model. Finally, it has been demonstrated with preliminary migration models that incipient melts generated directly below an ITSC may not necessarily erupt at that ITSC but migrate laterally towards a nearby ridge due to enhanced pressure gradients. The close proximity of the

  2. Use of MICRAS code on the evaluation of the maximum radionuclides concentrations due to transport/migration of decay chain in groundwaters

    International Nuclear Information System (INIS)

    Aquino Branco, O.E. de

    1995-01-01

    This paper presents a methodology for the evaluation of the maximum radionuclides concentrations in groundwaters, due to the transport/migration of decay chains. Analytical solution of the equations system is difficult, even if only three elements of the decay chain are considered. Therefore, a numerical solution is most convenient. An application of the MICRAS code, developed to assess maximum concentrations of each radionuclide, starting with the initial concentrations, is presented. The maximum concentration profile for 226 Ra, calculated using MICRAS, is compared with the results obtained through an analytical and a numerical model. The fitness of results is considered good. Simplified models, like the one represented by the application of MICRAS, are largely employed in the section in the selection and characterization of sites for radioactive wastes repositories and in studies of safety evaluation for the same purpose. A detailed analysis of the transport/migration of contaminants in aquifers requires a large quantify of data from the site and from the installation as well, which makes this analysis expensive and inviable during the preliminary phases of the studies. (author). 6 refs, 1 fig, 1 tab

  3. Evaluation of physical-protection elements for interior applications

    International Nuclear Information System (INIS)

    Scott, S.H.

    1983-01-01

    Considerable emphasis has been given in recent years to the threat of sabotage by an insider at nuclear facilities. This threat is inherently different from the outsider threat of theft or sabotage because of the insiders' unique knowledge and access to vital material and equipment. Thus, special safeguards elements are needed in order to counter the insider threat. In addition, insider physical protection system elements must be compatible with the operations, safety, and maintenance programs at the facility. To help identify elements which meet these needs, field evaluations were performed on an interior access control system, piping sensors, interior video motion detectors, and valve monitoring devices. These elements were tested in a realistic operating environment and both technical and operational evaluation data were obtained. Safeguards element descriptions and the results of the operational tests and evaluations are outlined

  4. Evaluation of in vivo labelled dendritic cell migration in cancer patients

    Directory of Open Access Journals (Sweden)

    Ridolfi Laura

    2004-07-01

    Full Text Available Abstract Background Dendritic Cell (DC vaccination is a very promising therapeutic strategy in cancer patients. The immunizing ability of DC is critically influenced by their migration activity to lymphatic tissues, where they have the task of priming naïve T-cells. In the present study in vivo DC migration was investigated within the context of a clinical trial of antitumor vaccination. In particular, we compared the migration activity of mature Dendritic Cells (mDC with that of immature Dendritic Cells (iDC and also assessed intradermal versus subcutaneous administration. Methods DC were labelled with 99mTc-HMPAO or 111In-Oxine, and the presence of labelled DC in regional lymph nodes was evaluated at pre-set times up to a maximum of 72 h after inoculation. Determinations were carried out in 8 patients (7 melanoma and 1 renal cell carcinoma. Results It was verified that intradermal administration resulted in about a threefold higher migration to lymph nodes than subcutaneous administration, while mDC showed, on average, a six-to eightfold higher migration than iDC. The first DC were detected in lymph nodes 20–60 min after inoculation and the maximum concentration was reached after 48–72 h. Conclusions These data obtained in vivo provide preliminary basic information on DC with respect to their antitumor immunization activity. Further research is needed to optimize the therapeutic potential of vaccination with DC.

  5. A study of element migration in the Maqarin site (Jordan) by the means of column experiments: II. trace elements (Cr, Se, Mo, Re)

    International Nuclear Information System (INIS)

    Trotignon, L.; Bienvenu, P.; Provitina, O.; Rose, J.; Khoury, H.; Trocellier, P.; Mercier, F.; Raimbault, L.

    2005-01-01

    Full text of publication follows: The site of Maqarin (Jordan), in which natural cements occur as a result of the combustion metamorphism of a bio-micrite, is studied since 1989 as a natural analogue for the long term evolution of a cementitious repository environment [1]. Several trace elements of interest (Cr, Se, Mo, Re) are mobilized on this site by percolating groundwaters and migrate along high pH plumes. Laboratory scale column experiments were conducted in which crushed materials (cement, bio-micrite) collected on site were submitted to leaching by deionized water or Ca(OH) 2 equilibrated solutions. The evolution of Cr, Mo, Se and Re was monitored in leachates during the experiments. Characterizations of the solid phase using several techniques were also conducted in order to locate these elements in the mineral phases. Comparison of experimental data with records of trace element concentration in Maqarin groundwaters gives some insight on Re, Cr, Se and Mo sources and sinks in this environment. Both the imprint of the past combustion event and present day redox transformations explain several features of the datasets. However, due to the high complexity of the cements, in which trace elements are often distributed among several mineral phases, it is presently not possible to link in a straightforward way individual mineral dissolution processes and trace element signals in waters. [1] Khoury H. N., Salameh E., Clark I. D., Fritz P., Bajjali W., Milodowski A. E., Cave M. R. and Alexander W. R. 1992. A natural analogue of high pH cement pore waters from the Maqarin area of northern Jordan. I: Introduction to the site. J. Geochem. Explor. 46: 117-132. (authors)

  6. Testing nano-silver food packaging to evaluate silver migration and food spoilage bacteria on chicken meat.

    Science.gov (United States)

    Gallocchio, Federica; Cibin, Veronica; Biancotto, Giancarlo; Roccato, Anna; Muzzolon, Orietta; Carmen, Losasso; Simone, Belluco; Manodori, Laura; Fabrizi, Alberto; Patuzzi, Ilaria; Ricci, Antonia

    2016-06-01

    Migration of nanomaterials from food containers into food is a matter of concern because of the potential risk for exposed consumers. The aims of this study were to evaluate silver migration from a commercially available food packaging containing silver nanoparticles into a real food matrix (chicken meat) under plausible domestic storage conditions and to test the contribution of such packaging to limit food spoilage bacteria proliferation. Chemical analysis revealed the absence of silver in chicken meatballs under the experimental conditions in compliance with current European Union legislation, which establishes a maximum level of 0.010 mg kg(-1) for the migration of non-authorised substances through a functional barrier (Commission Regulation (EU) No. 10/2011). On the other hand, microbiological tests (total microbial count, Pseudomonas spp. and Enterobacteriaceae) showed no relevant difference in the tested bacteria levels between meatballs stored in silver-nanoparticle plastic bags or control bags. This study shows the importance of testing food packaging not only to verify potential silver migration as an indicator of potential nanoparticle migration, but also to evaluate the benefits in terms of food preservation so as to avoid unjustified usage of silver nanoparticles and possible negative impacts on the environment.

  7. 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.

  8. Data base for a site-specific migration analysis radioactive elements out of a waste repository

    Energy Technology Data Exchange (ETDEWEB)

    Hadermann, J

    1981-11-01

    Migration analysis is of considerable importance in long-term safety analysis of radioactive waste repositories. In a first step our plans are to calculate transport of radionuclides using data - as far as possible - for an undisturbed hydrogeology. Thereby a reference case is defined. In a later step, possible events and processes can be considered leading to a deviation from the reference case. The present work gives the data base for a selected part of a comprehensive geosphere transport calculation. We restrict ourselves to a critical evaluation of parameters pertinent to the migration analysis of the /sup 245/Cm chain. This includes the important nuclide /sup 237/Np. For the first time we are able to perform a site specific calculation for repositories planned in deep geologic formations in Switzerland. The well-known fact that the data basis is extremely sparse is pointed out once more and concretized in detail.

  9. Evaluation of Endocrine Disrupting Compounds Migration in Household Food Containers under Domestic Use Conditions.

    Science.gov (United States)

    Sáiz, Jorge; Gómara, Belén

    2017-08-09

    Plasticizers and plastic monomers are commonly used in packaging. Most of them act as endocrine disrupters and are susceptible to migrate from the packaging to the food. We evaluated the migration of endocrine disrupting compounds from three different household food containers to four food simulants under different domestic treatments and for different periods of time, with the aim of reproducing real domestic conditions. The results showed that the migration to the simulants increased with the storage time, up to more than 50 times in certain cases. The heating power seemed to increase the migration processes (up to more than 30 times), and reusing containers produced an increase or decrease of the concentrations depending on the container type and the simulant. The concentrations found were lower than other concentrations reported (always less than 4000 pg/mL, down to less than 20 pg/mL), which might be a consequence of the domestic conditions used.

  10. [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

  11. 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)

  12. 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.

  13. Assessing Task Migration Impact on Embedded Soft Real-Time Streaming Multimedia Applications

    Directory of Open Access Journals (Sweden)

    Alimonda Andrea

    2008-01-01

    Full Text Available Abstract Multiprocessor systems on chips (MPSoCs are envisioned as the future of embedded platforms such as game-engines, smart-phones and palmtop computers. One of the main challenge preventing the widespread diffusion of these systems is the efficient mapping of multitask multimedia applications on processing elements. Dynamic solutions based on task migration has been recently explored to perform run-time reallocation of task to maximize performance and optimize energy consumption. Even if task migration can provide high flexibility, its overhead must be carefully evaluated when applied to soft real-time applications. In fact, these applications impose deadlines that may be missed during the migration process. In this paper we first present a middleware infrastructure supporting dynamic task allocation for NUMA architectures. Then we perform an extensive characterization of its impact on multimedia soft real-time applications using a software FM Radio benchmark.

  14. Assessing Task Migration Impact on Embedded Soft Real-Time Streaming Multimedia Applications

    Directory of Open Access Journals (Sweden)

    Andrea Acquaviva

    2008-01-01

    Full Text Available Multiprocessor systems on chips (MPSoCs are envisioned as the future of embedded platforms such as game-engines, smart-phones and palmtop computers. One of the main challenge preventing the widespread diffusion of these systems is the efficient mapping of multitask multimedia applications on processing elements. Dynamic solutions based on task migration has been recently explored to perform run-time reallocation of task to maximize performance and optimize energy consumption. Even if task migration can provide high flexibility, its overhead must be carefully evaluated when applied to soft real-time applications. In fact, these applications impose deadlines that may be missed during the migration process. In this paper we first present a middleware infrastructure supporting dynamic task allocation for NUMA architectures. Then we perform an extensive characterization of its impact on multimedia soft real-time applications using a software FM Radio benchmark.

  15. Evaluation of upward migration around a deep injection well

    International Nuclear Information System (INIS)

    Chia, Yeeping; Chiu, J.

    1994-01-01

    The long-term containment of injected wastes in the deep subsurface is expected to be achieved under suitable geologic and hydrologic conditions and by the use of competent engineering practices. Field experiences, however, indicate that waste containment may be affected by hydrologic conduits around the injection well. To assess the potential effects of these conduits, upward migration of injected waste is examined through the use of numerical models under various conditions. Test results indicate that without any preferential hydrologic conduits, most of the injected waste moves laterally in the injection interval, whereas only a small amount of waste migrates upward into the containment interval. When vertical fractures in the disturbed zone or defects in the cement seal around the wellbore exist, the contaminant can move rapidly upward along these conduits to an overlying aquifer, from which it migrates in the lateral direction. The contamination of the overlying aquifer that results from the upward migration of injected waste through these conduits cannot be impeded by a thick, low-permeability containment interval. However, when permeable interbeds exist within the containment interval, a significant portion of the waste migrating upward can be diverted laterally before reaching the overlying aquifer. The front of built-up pressure can reach the aquifer or permeable interbed immediately overlying the injection interval through the preferential hydrologic conduits shortly after the injection starts, but it cannot move farther upward because of pressure dissipation in the permeable formation. This study suggests that the injected waste has the potential to migrate upward into overlying formations through preferential migration conduits around the wellbore

  16. Elemental composition of otoliths from migrating chum salmon, Oncorhynchus keta, captured at the Kitakami river and Ishinomaki Bay

    International Nuclear Information System (INIS)

    Kakuta, Izuru; Iizuka, Keiki; Sugawara, Yoshio; Tsuchiya, Takeshi; Ishii, Keizo

    2000-01-01

    The elemental composition (Ca, Sr, Zn and Fe) of otoliths from migrating chum salmon, Oncorhynchus keta, captured at the Kitakami river and Ishinomaki Bay was analyzed to understand the migratory history using a particle induced X-ray emission (PIXE) technique. The Sr/Ca ratio of salmon otoliths was lower (less than 1 x 10 -3 ) in the portion formed in a freshwater environment and higher (approximately 4.8 x 10 -3 ) in a sea water environment. When the fish migrated from sea water into a freshwater environment, the otoliths' Sr/Ca ratios significantly increased. The highest values were found in the fish captured at the lower part of the Kitakami river (about 20 km upriver from the mouth). The values from the fish captured at the upper part of the Kitakami river (about 200 km upriver from the mouth) were also not less than those of the fish captured at Ishinomaki Bay. Abnormally high otolith Sr/Ca ratios for these upriver-migrating fish, when compared to the values from non-migrating salmon inhabiting stable environmental (salinity and temperature) conditions, provided evidence that they were stressed. No significant changes in the otoliths' Zn/Ca ratios were found, while these values were inversely proportional to the Sr/Ca ratios. However, a rapid drop in the Zn/Ca ratio and an increase in the Sr/Ca ratio was observed in some individuals in which higher values for the Fe/Ca were found. These results suggest that these otolith parameters don't exactly reflect the salinity and temperature history in upriver-migrating chum salmon because the physiological mechanism of incorporation of Sr, Zn and Ca within the otolith of those fish is abnormal, though for fish in non-stressful conditions the Sr/Ca and the Zn/Ca ratios in otoliths are effective indices for predicting the history of environmental conditions experienced by the fish in the past. Regarding the relationship between the Sr/Ca and the Zn/Ca ratios, and also the Fe/Ca ratio, there is a possibility that they

  17. 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

  18. 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.

  19. Development and evaluation of separation elements

    International Nuclear Information System (INIS)

    Guimaraes, R.R.R.; Rocha, Z.

    1990-01-01

    For industrial testing of the uranium enrichment technology by the jet nozzle process, it is being erected in Resende the 'First Cascade' (FC) and it was built the Separation Element Plant (FES). For the development, optimization and quality control of the separation elements produced by FES, it was set up in CDTN a laboratorial infrastructure. As part of it, it was designed, built and assembled the Separation Slit Testing Equipment (ITRS), with several components developed and constructed in CDTN. The tests are being carried out in ITRS with the objective of adjusting the machine tools of FES used in the line production of the separation elements. From the satisfactory results obtained with these tests, FES will start the production of separation tubes to be installed in FC. The objective of this paper is to describe the operation and evaluation tests in ITRS, as well as to present their contribution to the development and quality control of the separation elements produced in FES. (author) [pt

  20. 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

  1. Tritium migration at the Gasbuggy site: Evaluation of possible hydrologic pathways

    International Nuclear Information System (INIS)

    Chapman, J.; Mihevc, T.; Lyles, B.

    1996-09-01

    An underground nuclear test named Gasbuggy was conducted in northwestern New Mexico in 1967. Subsequent groundwater monitoring in an overlying aquifer by the U.S. Environmental Protection Agency revealed increasing levels of tritium in monitoring well EPNG 10-36, located 132 m from the test, suggesting migration of contaminants from the nuclear cavity. There are three basic scenarios that could explain the occurrence of tritium in well 10-36: (1) introduction of tritium into the well from the land surface, (2) migration of tritium through the Ojo Alamo Formation, and (3) migration through the Pictured Cliffs Formation. The two subsurface transport scenarios were evaluated with a travel time analysis. In one, transport occurs to the Ojo Alamo sandstone either up the emplacement hole or through fractures created by the blast, and then laterally through the aquifer to the monitoring well. In the other, lateral transport occurs through fractures in the underlying Pictured Cliffs detonation horizon and then migrates up the monitoring well through plugged casing connecting the two formations. The travel time analysis indicates that the hydraulic conductivity measured in the Ojo Alamo Formation is too low for lateral transport to account for the observed arrival of tritium at the monitoring well. This suggests transport either through fractures intersecting the Ojo Alamo close to well EPNG 10-36, or through fractures in the Pictured Cliffs and up through the bottom plug in the well. The transport scenarios were investigated using hydrologic logging techniques and sampling at the monitoring well, with the fieldwork conducted after the removal of a string of 0.05-m-diameter tubing that had previously provided the only monitoring access

  2. Evaluation of Tissue Interactions with Mechanical Elements of a Transscleral Drug Delivery Device

    Directory of Open Access Journals (Sweden)

    Jeffrey T. Borenstein

    2012-03-01

    Full Text Available The goal of this work was to evaluate tissue-device interactions due to implantation of a mechanically operated drug delivery system onto the posterior sclera. Two test devices were designed and fabricated to model elements of the drug delivery device—one containing a free-spinning ball bearing and the other encasing two articulating gears. Openings in the base of test devices modeled ports for drug passage from device to sclera. Porous poly(tetrafluoroethylene (PTFE membranes were attached to half of the gear devices to minimize tissue ingrowth through these ports. Test devices were sutured onto rabbit eyes for 10 weeks. Tissue-device interactions were evaluated histologically and mechanically after removal to determine effects on device function and changes in surrounding tissue. Test devices were generally well-tolerated during residence in the animal. All devices encouraged fibrous tissue formation between the sclera and the device, fibrous tissue encapsulation and invasion around the device, and inflammation of the conjunctiva. Gear devices encouraged significantly greater inflammation in all cases and a larger rate of tissue ingrowth. PTFE membranes prevented tissue invasion through the covered drug ports, though tissue migrated in through other smaller openings. The torque required to turn the mechanical elements increased over 1000 times for gear devices, but only on the order of 100 times for membrane-covered gear devices and less than 100 times for ball bearing devices. Maintaining a lower device profile, minimizing microscale motion on the eye surface and covering drug ports with a porous membrane may minimize inflammation, decreasing the risk of damage to surrounding tissues and minimizing disruption of device operation.

  3. The role of organics on the migration of radionuclides in the geosphere

    International Nuclear Information System (INIS)

    Carlsen, L.

    1989-01-01

    The present report summarizes factors of importance concerning the role of organics on the migration of radionuclides in the terrestrial environment. Following some introductory remarks (chapter 1), chapter 2 describes the occurrence of organic compounds in the geosphere, taking both naturally occurring as well as artificially introduced compounds into account. The behaviour of organic compounds in the terrestrial environment is summarized (chapter 3) with special emphasis on sorption and persistence in the environment. Both chemical and microbiological degradation reactions are discussed. Chapter 4 describes the fundamentals of complex formation in relation to migration. Stability constants for the interactions between relevant metal ions and low molecular weight ligands as well as with humic- and fulvic acids are summarized. Chapter 5 is devoted to an evaluation, based on theoretical considerations, of the influence of organics on the migration behaviour of radionuclides in the terrestrial environment. Additionally, the behaviour of two special elements, i.e. technetium and iodine, is discussed

  4. A study of element migration in the Maqarin site (Jordan) by the means of column experiments: I. major elements

    International Nuclear Information System (INIS)

    Trotignon, L.; Bienvenu, P.; Rose, J.; Bulle, C.; Crouzet, N.; Khoury, H.

    2005-01-01

    Full text of publication follows: The site of Maqarin (Jordan), in which natural cements occur as a result of the combustion metamorphism of a bio-micrite, is studied since 1989 as a natural analogue for the long term evolution of a cementitious repository environment [1]. In order to better understand and simulate observed elemental migrations along high pH groundwater plumes, laboratory scale column experiments were conducted in which crushed materials (cement, bio-micrite) collected on site were submitted to leaching by deionized water or Ca(OH) 2 equilibrated solutions. The evolution of pH and major elements was monitored in leachates (Ca, SO 4 , Si, Al) during the experiments. Simulations of the experiments were attempted using the reactive transport code Hytec (Ecole des Mines de Paris and Pole Geochimie Transport). The column experiments presented here contribute to a better understanding of the evolution of hyper-alkaline waters in Maqarin. They suggest several key parameters to be taken into account in the modelling of such systems: - the rate limited precipitation of CSH phases; - the pH dependence of ettringite dissolution (and probably precipitation); - the competition in the availability of Al and Si from the bio-micrite, showing to be a critical issue for modeling the alkaline perturbation Further experiments and modeling of this type is needed to understand how (and how fast) Maqarin groundwaters acquire their high pH. Such information will be useful to better bracket the extent of precipitation of secondary CSH phases in the near field of a repository. [1] Khoury H.N., Salameh E., Clark I.D., Fritz P., Bajjali W., Milodowski A.E., Cave M.R. and Alexander W.R. 1992. A natural analogue of high pH cement pore waters from the Maqarin area of northern Jordan. I: Introduction to the site. J. Geochem. Explor. 46: 117-132. (authors)

  5. Data base for a site specific migration analysis of radioactive elements from a final repository. Datenbasis fuer eine standortspezifische Ausbreitungsanalyse radioaktiver Elemente aus einem Endlager

    Energy Technology Data Exchange (ETDEWEB)

    Hadermann, J

    1981-11-01

    Migration analysis is of considerable importance in long-term safety analysis of radioactive waste repositories. In a first step our plans are to calculate transport of radionuclides using data - as far as possible - for an undisturbed hydrogeology. Thereby a reference case is defined. In a later step, possible events and processes can be considered leading to a deviation from the reference case. The present work gives the data base for a selected part of a comprehensive geosphere transport calculation. We restrict ourselves to a critical evaluation of parameters pertinent to the migration analysis of the /sup 245/Cm chain. This includes the important nuclide /sup 237/Np. For the first time we are able to perform a site specific calculation for repositories planned in deep geologic formations in Switzerland. The well known fact that the data basis is extremely sparse is pointed out once more and concretized in detail.

  6. 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.)

  7. 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.)

  8. 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

  9. 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.

  10. A basic evaluated neutronic data file for elemental scandium

    International Nuclear Information System (INIS)

    Smith, A.B.; Meadows, J.W.; Howerton, R.J.

    1992-01-01

    This report documents an evaluated neutronic data file for elemental scandium, presented in the ENDF/B-VI format. This file should provide basic nuclear data essential for neutronic calculations involving elemental scandium. No equivalent file was previously available

  11. Migration of plasticisers from PVC and other polymers

    DEFF Research Database (Denmark)

    Lundsgaard, Rasmus

    ). In this work it is shown how diffusion coefficients can be obtained by regression of experimental migration data plotted as the square root of time. This was done from plasticiser migration data of GRINDSTEDr SOFT-N-SAFE, GRINDSTEDr ACETEM 95 CO (Acetem) and Epoxidised Soybean Oil (ESBO) migrating from......The main purpose of this thesis is to investigate, from a modeling point of view, the migration of GRINDSTEDr SOFT-N-SAFE (SNS) and other plasticisers from polyvinyl chloride (PVC) and polyolefin food package materials and into foodstuff (specifically the four food simulants set by EU legislation...... coefficients at 20◦C, except at higher temperatures. Using the finite element mesh method in Matlab and COMSOL environments the migration was modeled with a diffusion coefficient able to change with local plasticiser concentration. Three different models for this plasticiser concentration dependence...

  12. Serbian migration policy concerning irregular migration and asylum in the context of the EU integration process

    Directory of Open Access Journals (Sweden)

    Marta Stojić-Mitrović

    2016-02-01

    Full Text Available In this paper I would like to present Serbian migration policy concerning irregular migration and asylum in the context of the attempts of the Serbian state to become a member of the European Union. I would describe the history of the asylum system prior and after the implementation of the independent asylum system in Serbia in 2008. My presentation of the Serbian migration policy would be channelled by the analysis of some particular political issues, such as the externalization of the EU borders’ control, as well as some relevant elements of the European integration process, like visa liberalization. The second, more culturally specific dimension of the issue would be accessed through the demonstration of both legislative and public conceptualizations of the irregular migrants, asylum seekers and refugees in Serbia.

  13. Sr - an element shows the way - Applications of Sr isotopes for provenance, tracing and migration (Invited)

    Science.gov (United States)

    Prohaska, T.; Irrgeher, J.; Zitek, A.; Teschler Nicola, M.

    2010-12-01

    Strontium - named after the small Scottish town Strontian - as such is an element with little popularity. Firstly described by Martin Heinrich Klaproth in 1798, the metal is used in metallurgy to some extent whereas its compounds are interesting in glass industries, electronics and pyrotechnics. The element has chemical similarity to Ca and makes up 1/60 of the earth’s amount of the latter. Nonetheless, it is its isotopic composition which makes Sr so interesting for a large number of scientists. The natural composition of the four naturally occurring isotopes (84Sr, 86Sr 87Sr and 88Sr) varies in nature due to the radioactive decay of 87Rb to 87Sr. Thus, it was early recognized as geochronometer especially in Ca rich matrices. With increasing precision of applied methodology, the natural variation of the 87Sr/86Sr isotope ratio (analyzed at first mainly by thermal ionization mass spectrometry (TIMS)) became more and more popular in provenance studies. The natural variation of the ratio is mainly determined by the geological age and the original composition of the rock and can be used therefore as fingerprint of the local geology. The ratio is transferred with no significant fractionation via the water into plants and finally via the food chain into animal and human tissues (especially bones and teeth). As the element is chemically similar to Ca, it appears in most matrices. The use for provenance studies is supported by the fact that the long half life (4.8 x 1010 years) does not lead to an alteration during the time scales which are investigated (from recent samples to human or animal skeletal remains which date back up to 30.000 BC). The uniqueness of the system besides the natural variation is defined by the ubiquity in nature and the relatively high (and thus measurable) elemental concentration in most tissues. It was finally the advent of multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS) which augmented the number of applications

  14. Comparative test on nuclide migration in aerated zone

    International Nuclear Information System (INIS)

    Li Shushen; Zhao Yingjie; Wu Qinghua; Wang Zhiming; Hao Janzhong; Ji Shaowei; Guo Liangtian; Guo Zhiming

    2002-01-01

    In order to study the influence of different tracer source layer material on nuclide migration behavior, the comparative test on stable elements Sr, Nd and Ce migration in aerated loess zone was carried out using loess and arenaceous quartz as the tracer source layer materials respectively. The test lasted 470 days. During the test, four times of sampling were done. The testing results indicate that under artificial sprinkling of 5 mm/h and 3 h/d, Nd and Ce not only in loess tracer source layer but also in arenaceous quartz tracer source layer did not obviously downwards migrated. Concentration peak of Sr for loess layer migrated down about 15 cm in 470 d (mass center moved down about 10 cm) but for arenaceous quartz layer the concentration peak of Sr did not obviously migrated down (mass center moved down about 2.7 cm). The test results show that very thin arenaceous quartz layer with thickness of 7 mm is also able to shield unsaturated water flow obviously. This is the main reason why the nuclides in arenaceous quartz layer migrate down slowly

  15. Reverse time migration by Krylov subspace reduced order modeling

    Science.gov (United States)

    Basir, Hadi Mahdavi; Javaherian, Abdolrahim; Shomali, Zaher Hossein; Firouz-Abadi, Roohollah Dehghani; Gholamy, Shaban Ali

    2018-04-01

    Imaging is a key step in seismic data processing. To date, a myriad of advanced pre-stack depth migration approaches have been developed; however, reverse time migration (RTM) is still considered as the high-end imaging algorithm. The main limitations associated with the performance cost of reverse time migration are the intensive computation of the forward and backward simulations, time consumption, and memory allocation related to imaging condition. Based on the reduced order modeling, we proposed an algorithm, which can be adapted to all the aforementioned factors. Our proposed method benefit from Krylov subspaces method to compute certain mode shapes of the velocity model computed by as an orthogonal base of reduced order modeling. Reverse time migration by reduced order modeling is helpful concerning the highly parallel computation and strongly reduces the memory requirement of reverse time migration. The synthetic model results showed that suggested method can decrease the computational costs of reverse time migration by several orders of magnitudes, compared with reverse time migration by finite element method.

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

    Science.gov (United States)

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

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

  17. Comparative evaluation of trace elements in blood

    International Nuclear Information System (INIS)

    Goeij, J.J.M. de; Tjioe, P.S.; Pries, C.; Zwiers, J.H.L.

    1976-01-01

    The Interuniversitair Reactor Instituut and the Centraal Laboratorium TNO have carried out a common investigation on neutron-activation-analytical procedures for the determination of trace elements in blood. A comparative evaluation of five methods, destructive as well as non-destructive, is given. The sensitivity and reproducibility of the procedures are discussed. By combining some of the methods it is possible, starting with 1 ml blood, to give quantitative information on 14 important trace elements: antimony, arsenic, bromine, cadmium, cobalt, gold, copper, mercury, molybdenum, nickel, rubidium, selenium, iron and zinc. The methods have also been applied to sodium, chromium and potassium

  18. Media and migration. Layers of knowledge in Romanian written press

    Directory of Open Access Journals (Sweden)

    Ștefania Matei

    2011-11-01

    Full Text Available This paper seeks to discuss the image that the media build around the phenomenon of migration in present-day Romanian society. I rely on a content analysis of newspaper articles on migration in order to explore layers of knowledge (understood as evidence which forms the basis of the representation about an issue by identifying specific elements in each and every piece of news, such as: the current state of migration, the demographic profile of the migrant, geographical location, the orientation of the newspaper, the situation of migrants, the causes and effects of this phenomenon, and the policies implemented in the communities of origin and destination, respectively. All these elements are examined along the lines of emigration and immigration in order to reconstruct strategies of framing external migration within the journalistic discourse, and to identify the information which constitutes a reference point in shaping the attribute agenda on this topic. The discussion relies on the analysis of 473 articles in Romanian newspapers, published between 2007 and 2009, using as a sampling frame the archive of articles available on the website www.ziare.com.

  19. Simplified method of evaluation of radionuclides migration in soil; Methode simplifiee d'evaluation de la migration de radionucleides dans le sol

    Energy Technology Data Exchange (ETDEWEB)

    Rozel, Ch

    1998-06-01

    In the frame of safety studies, it is useful to know the advance of an eventual release of radionuclides in ground water to determine the radiological impact on man by water ingestion, by irrigated plants ingestion and animals production ingestion (such milk or meat). The objectives of this report are to present the different physics phenomenons encountered during the migration, to list the different methods of doing ( to determine the radionuclides migration in soil), to choose one method and to check the results coherence with experience return. (N.C.)

  20. Migration to Alma/Primo: A Case Study of Central Washington University

    Directory of Open Access Journals (Sweden)

    Ping Fu

    2015-12-01

    Full Text Available This paper describes how Central Washington University Libraries (CWUL interacted and collaborated with the Orbis Cascade Alliance (OCA Shared Integrated Library System’s (SILS Implementation Team and Ex Libris to process systems and data migration from Innovative Interfaces Inc.’s Millennium integrated library system to Alma/Primo, Ex Libris’ next-generation library management solution and discovery and delivery solution. A chronological review method was used for this case study to provide an overall picture of key migration events, tasks, and implementation efforts, including pre-migration cleanup, migration forms, integration with external systems, testing, cutover, post-migration cleanup, and reporting and fixing outstanding issues. A three-phase migration model was studied, and a questionnaire was designed to collect data from functional leads to determine staff time spent on the migration tasks. Staff time spent on each phase was analyzed and quantitated, with some top essential elements for the success of the migration identified through the case review and data analysis. An analysis of the Ex Libris’ Salesforce cases created during the migration and post-migration was conducted to be used for identifying roles of key librarians and staff functional leads during the migration.

  1. [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.

  2. Evaluation of host rocks and background lithologies as secondary contributors to the uranium and rare-earth element source-term at the Needle's Eye natural analogue site

    International Nuclear Information System (INIS)

    Hyslop, E.K.

    1993-01-01

    HMIP has a research programme investigating some naturally radioactive sites in the UK as geochemical analogues of radionuclide migration. The objective is to test thermodynamic database and computer codes used for modelling radionuclide migration under environmental conditions. This report describes a study of the distributions of uranium (U) and the rare-earth elements (REE) in the vicinity of pitchblende veins outcropping in the cliff at Needle's Eye on the Solway Coats, SW Scotland. This report improves the information available on the secondary source-terms of U and REE. The minerals in the country rocks are thought to be supplying only minor amounts of these elements to the groundwaters flowing into the Merse silts within the detailed study area close to the mineralisation in the cliff. The pitchblende veins are the principal source-term for U migrating into the Merse silts at the foot of the cliff. (author)

  3. Effect of crystal orientation on grain boundary migration and radiation-induced segregation

    International Nuclear Information System (INIS)

    Hashimoto, N.; Eda, Y.; Takahashi, H.

    1996-01-01

    Fe-Cr-Ni, Ni-Al and Ni-Si alloys were electron-irradiated using a high voltage electron microscope (1 MeV), and in situ observations of the structural evolution and micro-chemical analysis were carried out. During the irradiation, the grain boundaries in the irradiated region migrated, while no grain boundary migration occurred in the unirradiated area. The occurrence of boundary migration depended on the orientation relationship of the boundary interfaces. Grain boundary migration took place in Fe-Cr-Ni and Ni-Si alloys with large crystal orientation difference between the two grains across a grain boundary. In Ni-Al, however, the grain boundary migration did not occur. The solute segregation was caused at grain boundary under irradiation and this segregation behavior was closely related to solute size, namely the concentrations of undersized Ni and oversized Cr elements in Fe-Cr-Ni alloy increased and reduced at grain boundary, respectively. The same dependence of segregation on the solute size was derived in Ni-Si and Ni-Al alloys, in which Si and Al solutes are undersized and oversized elements, respectively. Therefore, Si solute enriched and Al solute depleted at grain boundary. From the present segregation behavior, it is suggested that the flow of point defects into the boundary is the cause of grain boundary migration. (orig.)

  4. Oriental Elements in the Material Culture of Azaq and the Problem of Migrations of the Golden Horde Urban Population

    Directory of Open Access Journals (Sweden)

    Maslovskiy Andrey N.

    2013-12-01

    Full Text Available The data on the emergence of new Oriental material culture elements in the city of Azaq, such as new housing and pottery types, characteristic of the mid-14th-century Golden Horde cities of the Lower Volga region, are provided in the article. Particular attention is paid to the appearance of new types of dwellings with the kang-based system of heating. They make up about 10 per cent of all residential complexes studied in Azaq: mostly ground dwellings, as semi-subterranean dwellings with kangs are rarely met. It has been suggested that in the mid-14th century a considerable group of residents of the Golden Horde Lower Volga towns had migrated to Azaq. The reasons for this relocation can be discussed only hypothetically.

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

    International Nuclear Information System (INIS)

    Tanaka, Yukihisa; Hironaga, Michihiko

    2014-01-01

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

  6. Criticality safety evaluation for the Advanced Test Reactor enhanced low enriched uranium fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Montierth, Leland M. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-07-19

    The Global Threat Reduction Initiative (GTRI) convert program is developing a high uranium density fuel based on a low enriched uranium (LEU) uranium-molybdenum alloy. Testing of prototypic GTRI fuel elements is necessary to demonstrate integrated fuel performance behavior and scale-up of fabrication techniques. GTRI Enhanced LEU Fuel (ELF) elements based on the ATR-Standard Size elements (all plates fueled) are to be fabricated for testing in the Advanced Test Reactor (ATR). While a specific ELF element design will eventually be provided for detailed analyses and in-core testing, this criticality safety evaluation (CSE) is intended to evaluate a hypothetical ELF element design for criticality safety purposes. Existing criticality analyses have analyzed Standard (HEU) ATR elements from which controls have been derived. This CSE documents analysis that determines the reactivity of the hypothetical ELF fuel elements relative to HEU ATR elements and whether the existing HEU ATR element controls bound the ELF element. The initial calculations presented in this CSE analyzed the original ELF design, now referred to as Mod 0.1. In addition, as part of a fuel meat thickness optimization effort for reactor performance, other designs have been evaluated. As of early 2014 the most current conceptual designs are Mk1A and Mk1B, that were previously referred to as conceptual designs Mod 0.10 and Mod 0.11, respectively. Revision 1 evaluates the reactivity of the ATR HEU Mark IV elements for a comparison with the Mark VII elements.

  7. Criticality safety evaluation for the Advanced Test Reactor enhanced low enriched uranium fuel elements

    International Nuclear Information System (INIS)

    Montierth, Leland M.

    2016-01-01

    The Global Threat Reduction Initiative (GTRI) convert program is developing a high uranium density fuel based on a low enriched uranium (LEU) uranium-molybdenum alloy. Testing of prototypic GTRI fuel elements is necessary to demonstrate integrated fuel performance behavior and scale-up of fabrication techniques. GTRI Enhanced LEU Fuel (ELF) elements based on the ATR-Standard Size elements (all plates fueled) are to be fabricated for testing in the Advanced Test Reactor (ATR). While a specific ELF element design will eventually be provided for detailed analyses and in-core testing, this criticality safety evaluation (CSE) is intended to evaluate a hypothetical ELF element design for criticality safety purposes. Existing criticality analyses have analyzed Standard (HEU) ATR elements from which controls have been derived. This CSE documents analysis that determines the reactivity of the hypothetical ELF fuel elements relative to HEU ATR elements and whether the existing HEU ATR element controls bound the ELF element. The initial calculations presented in this CSE analyzed the original ELF design, now referred to as Mod 0.1. In addition, as part of a fuel meat thickness optimization effort for reactor performance, other designs have been evaluated. As of early 2014 the most current conceptual designs are Mk1A and Mk1B, that were previously referred to as conceptual designs Mod 0.10 and Mod 0.11, respectively. Revision 1 evaluates the reactivity of the ATR HEU Mark IV elements for a comparison with the Mark VII elements.

  8. Expectations, gender, and norms in migration decision-making.

    Science.gov (United States)

    DE Jong, Gordon F

    2000-01-01

    This paper argues that expectations - the process of evaluating the chances for future attainment of valued goals in the home community (stay decision) vs. alternative locations (move decision) - along with family norms about migration are major predictors of intention to move, which in turn is a proximate determinant of migration behaviour. Utilizing longitudinal data from the 1992 and 1994 waves of the Thailand National Migration Survey, logistic regression models show that a strikingly different set of expectations, household demographic indicators, and migrant capital factors were significant determinants of migration intentions for men and women; reflecting Thai gender roles. Migration intentions, in turn, predicted more permanent, but not temporary, survival strategy migration behaviour, while low household income predicted temporary but not more permanent migration behaviour. The measure of perceived family migration norms was a powerful determinant of migration behaviour, but the size of migrant networks was not a statistically significant determinant of either migration intentions or behaviour.

  9. Review of investigations on U, Tr, Ra isotopes migration in biosphere

    International Nuclear Information System (INIS)

    Titaeva, N.A.; Taskaev, A.I.

    1983-01-01

    Fragmentary data on uranium, thorium and radium isotope migration in biosphere which have been accumulated by today are generalized. It is shown that isotopes of one element with different degree of intensity migrate by the chain soil-plants. Lack of data on soil and plants is observed alongside with good awareness of U, Th and Ra isotope composition in abiogenic natural formations such as, soils, waters and bottom depositions

  10. Experimental Studies to Evaluate the Role of Colloids on the Radionuclide Migration in a Crystalline Medium

    International Nuclear Information System (INIS)

    Albarran, Nairoby; Missana, Tiziana; Alonso, Ursula; Garcia-Gutierrez, Miguel; Mingarro, Manuel; Lopez, Trinidad

    2008-01-01

    In a deep geological repository (DGR) of high level radioactive waste, all the possible phenomena affecting radionuclide migration have to be studied to assess its security over time. Colloids can play an important role for contaminant transport if the following conditions are fulfilled: colloids exist in a non negligible concentration, they are mobile and stable in the environment of interest, and they are able to adsorb radionuclides irreversibly. In this study, different transport experiments where performed to improve the knowledge on the main mechanisms affecting the radionuclide migration in the presence of colloids in a crystalline medium. Firstly, colloid stability was analysed and then transport experiments in an artificial granite longitudinal fracture were carried out. Synthetic colloids of different size and bentonite clay colloids were used to evaluate the effects of colloid size, charge, and water flow rate on their mobility. Results showed that both major importance of the water flow rate on the mobility of colloids and their recovery and a higher interaction of smaller particles with the surface. Finally, the migration behaviour of Sr, and Sr adsorbed onto bentonite colloids was compared. The elution curves of Sr adsorbed onto colloid were significantly different from the ones of Sr alone, pointing out that sorption/desorption mechanisms must be taken into account to understand the radionuclide migration in the fracture in the presence of colloids. (authors)

  11. The Notion of “Social Networks” in Migration

    Directory of Open Access Journals (Sweden)

    Marie-Antoinette Hily

    2006-12-01

    Full Text Available What it means to focus on the notion of “social network” from a migration point of view? By exploring this question, the authors describe the conceptual framework of this concept. Developed in the field of urban anthropology, with a scientific approach of the social combining “relation” and “situation”, the notion of network continued its career in the field of the sociology of the migrations. By introducing elements of complexity into the analysis, this notion made it possible to break with an approach based on the “communautarist” approach of the migrant groups.

  12. Modelling of migration of radionuclides and trace elements between the components of the Black Sea ecosystems

    International Nuclear Information System (INIS)

    Egorov, V.N.

    1999-01-01

    This report considers peculiarities of the mathematical description of radionuclides migration between water environment and biotic and abiotic components of the Black Sea ecosystems at different periods of averaging, from the time scale of metabolic processes, taking place in hydrobionts, to the large-scale description of radionuclides migration in the Black Sea

  13. International Elderly Migration in Hungary

    Directory of Open Access Journals (Sweden)

    Sándor Illés

    2006-06-01

    Full Text Available The paper examines international elderly migration (IEM related to Hungary. Little effort has been made to investigate this increasingly important element of human migration in Central and Eastern Europe. The general objective of this study is to contribute to filling this gap. IEM is investigated using register-based data on migration flows, stocks and citizenship statistics. The analysis focuses on the time series but the paper also considers the historical context and the recent patterns of IEM. The aim of the research was fourfold. Firstly, we tried to establish when IEM related to Hungary began. Secondly, we detected the accelerating character of this phenomenon. Thirdly, we were able to identify the main macrofactors influencing the level of IEM. Fourthly, the main result of the study was that it allowed exploration of a Hungarian peculiarity. “Pension seeking” is one very distinctive feature of IEM and is in many ways a legacy of the state socialism period. Therefore, its emergence on such a large scale is the result of the transformation period. We suppose that pension-hunting type migration will be temporary in nature. Conclusions about the motivational structure of IEM are discussed with reference to policy implications in the light of the ageing population structure in Hungary.

  14. 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

  15. Field tests on migration of TRU-nuclide, (2). Migration test for engineered barrier materials in aerated soil

    International Nuclear Information System (INIS)

    Maeda, Toshikatsu; Tanaka, Tadao; Mukai, Masayuki

    2003-01-01

    Field tests on migration of radionuclides for engineered barrier materials such as bentonite and cementitious materials were performed. The tests were run under both wet conditions with artificial rainfall and dry conditions with natural rainfall. Laboratory experiments such as batch adsorption tests were also conducted to analyze the result of field test. The results of field tests agreed with the predicted moisture conditions and the migration behaviors observed at the laboratory experiment that is reported so far. For bentonite material, the movements of the tracer were calculated using known information such as the results of batch sorption tests and migration mechanism. Comparing the result of field test and calculations, it is suggested that tracer migration behavior in bentonite material in field can be evaluated quantitatively by the known migration mechanism and the results of laboratory experiments such as batch sorption test. (author)

  16. [The foundation of international migration policies in Latin America].

    Science.gov (United States)

    Marmora, L

    1988-12-01

    A government's international migration policies are intended to influence the size, composition, direction, destination, or integration of international migratory flows. The justification for migratory policies has been based on a series of themes that have had varied weights in different stages of Latin American history. Migrations as population settlement, the desired or undesired characteristics of migrants, the economic impact of migration, the role of migration in relations between countries, and the ethical dimensions of migratory movement have been the major policy issues. The 1st migration policies in Latin America saw international migration as a means of settling the colonies. After independence, migratory policies oriented toward massive settlement became common. Although the stated goals were to settle entire territories with immigrants, the usual result was to absorb immigrants in certain economic sectors with high demand for labor. In the colonial period both Spain and Portugal attempted to restrict immigration to the Catholic segment of their own populations. After independence, the criteria were liberalized somewhat but still reflected prejudices about the racial superiority of certain types of European immigration. The selection principals which appeared most clearly during the 19th century were overwhelmed to the extent that immigration was tranformed into provision of labor to meet unsatisfied needs for workers. Indiscriminate admissions and recourse to nontraditional elements such as Chinese and Japanese was strongest in countries needing labor for tropical agriculture or extractive industries. The economic argument that migration contributed to development was widespread economic argument that migration contributed to development was widespread in the 19th and early 20th centuries, but new rules were made to restrict immigration to protect local labor markets during the worldwide depression of the 1930s. In recent decades, migration policies

  17. Ground test facilities for evaluating nuclear thermal propulsion engines and fuel elements

    International Nuclear Information System (INIS)

    Allen, G.C.; Beck, D.F.; Harmon, C.D.; Shipers, L.R.

    1992-01-01

    Interagency panels evaluating nuclear thermal propulsion development options have consistently recognized the need for constructing a major new ground test facility to support fuel element and engine testing. This paper summarizes the requirements, configuration, and design issues of a proposed ground test complex for evaluating nuclear thermal propulsion engines and fuel elements being developed for the Space Nuclear Thermal Propulsion (SNTP) program. 2 refs

  18. Towards an integrated model of international migration

    Directory of Open Access Journals (Sweden)

    Douglas S. MASSEY

    2012-12-01

    Full Text Available Demographers have yet to develop a suitable integrated model of international migration and consequently have been very poor at forecasting immigration. This paper outlines the basic elements of an integrated model and surveys recent history to suggest the key challenges to model construction. A comprehensive theory must explain the structural forces that create a supply of people prone to migrate internationally, the structural origins of labour demand in receiving countries, the motivations of those who respond to these forces by choosing to migrate internationally, the growth and structure of transnational networks that arise to support international movement, the behaviour states in response to immigrant flows, and the influence of state actions on the behaviour of migrants. Recent history suggests that a good model needs to respect the salience of markets, recognize the circularity of migrant flows, appreciate the power of feedback effects, and be alert unanticipated consequences of policy actions.

  19. Modelling of radionuclide migration and heat transport from an High-Level-Radioactive-Waste-repository (HLW) in Boom clay

    International Nuclear Information System (INIS)

    Put, M.; Henrion, P.

    1992-01-01

    For the modelling of the migration of radionuclides in the Boom clay formation, the analytical code MICOF has been updated with a 3-dimensional analytical solution for discrete sources. the MICOF program is used for the calculation of the release of α and β emitters from the HIGH LEVEL RADIOACTIVE WASTES (HLW). A coherent conceptual model is developed which describes all the major physico-chemical phenomena influencing the migration of radionuclides in the Boom clay. The concept of the diffusion accessible porosity is introduced and included in the MICOF code. Different types of migration experiments are described with their advantages and disadvantages. The thermal impact of the HLW disposal in the stratified Boom clay formation has been evaluated by a finite element simulation of the coupled heat and mass transport equation. The results of the simulations show that under certain conditions thermal convection cells may form, but the convective heat transfer in the clay formation is negligible. 6 refs., 19 figs., 2 tabs., 5 appendices

  20. Evaluating damping elements for two-stage suspension vehicles

    Directory of Open Access Journals (Sweden)

    Ronald M. Martinod R.

    2012-01-01

    Full Text Available The technical state of the damping elements for a vehicle having two-stage suspension was evaluated by using numerical models based on the multi-body system theory; a set of virtual tests used the eigenproblem mathematical method. A test was developed based on experimental modal analysis (EMA applied to a physical system as the basis for validating the numerical models. The study focused on evaluating vehicle dynamics to determine the influence of the dampers’ technical state in each suspension state.

  1. An evaluated neutronic data file for elemental zirconium

    International Nuclear Information System (INIS)

    Smith, A.B.; Chiba, S.

    1994-09-01

    A comprehensive evaluated neutronic data file for elemental zirconium is derived and presented in the ENDF/B-VI formats. The derivation is based upon measured microscopic nuclear data, augmented by model calculations as necessary. The primary objective is a quality contemporary file suitable for fission-reactor development extending from conventional thermal to fast and innovative systems. This new file is a significant improvement over previously available evaluated zirconium files, in part, as a consequence of extensive new experimental measurements reported elsewhere

  2. Modeling potential migration of petroleum hydrocarbons from a mixed-waste disposal site in the vadose zone

    International Nuclear Information System (INIS)

    Rawson, S.A.; Walton, J.C.; Baca, R.G.

    1989-01-01

    Environmental monitoring of a mixed-waste disposal site at the Idaho National Engineering Laboratory has confirmed release and migration into the vadose zone of: (1) chlorinated hydrocarbons in the vapor phase and (2) trace levels of certain transuranic elements. The finding has prompted an evaluation of the potential role of waste petroleum hydrocarbons in mediating or influencing contaminant migration from the disposal site. Disposal records indicate that a large volume of machine oil contaminated with transuranic isotopes was disposed at the site along with the chlorinated solvents and other radioactive wastes. A multiphase flow model was used to assess the possible extent of oil and vapor movement through the 177 m thick vadose zone. One dimensional simulations were performed to estimate the vertical distribution of the vapor phase, the aqueous phase, and immiscible free liquid as a function of time. The simulations indicate that the oil may migrate slowly through the vadose zone, to potentially significant depths. Calculated transport rates support the following ranking with regard to relative mobility: vapor phase > aqueous phase > free liquid. 21 refs., 7 figs., 2 tabs

  3. Java Source Code Analysis for API Migration to Embedded Systems

    Energy Technology Data Exchange (ETDEWEB)

    Winter, Victor [Univ. of Nebraska, Omaha, NE (United States); McCoy, James A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Guerrero, Jonathan [Univ. of Nebraska, Omaha, NE (United States); Reinke, Carl Werner [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Perry, James Thomas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-02-01

    Embedded systems form an integral part of our technological infrastructure and oftentimes play a complex and critical role within larger systems. From the perspective of reliability, security, and safety, strong arguments can be made favoring the use of Java over C in such systems. In part, this argument is based on the assumption that suitable subsets of Java’s APIs and extension libraries are available to embedded software developers. In practice, a number of Java-based embedded processors do not support the full features of the JVM. For such processors, source code migration is a mechanism by which key abstractions offered by APIs and extension libraries can made available to embedded software developers. The analysis required for Java source code-level library migration is based on the ability to correctly resolve element references to their corresponding element declarations. A key challenge in this setting is how to perform analysis for incomplete source-code bases (e.g., subsets of libraries) from which types and packages have been omitted. This article formalizes an approach that can be used to extend code bases targeted for migration in such a manner that the threats associated the analysis of incomplete code bases are eliminated.

  4. Soil type affects migration pattern of airborne Pb and Cd under a spruce-beech forest of the UN-ECE integrated monitoring site Zoebelboden, Austria

    Energy Technology Data Exchange (ETDEWEB)

    Kobler, Johannes, E-mail: johannes.kobler@umweltbundesamt.a [Umweltbundesamt, Spittelauer Laende 5, 1090 Vienna (Austria); Fitz, Walter J.; Dirnboeck, Thomas; Mirtl, Michael [Umweltbundesamt, Spittelauer Laende 5, 1090 Vienna (Austria)

    2010-03-15

    Anthropogenic trace element emissions have declined. However, top soils all over the world remain enriched in trace elements. We investigated Pb and Cd migration in forest soils of a remote monitoring site in the Austrian limestone Alps between 1992 and 2004. Large spatial variability masked temporal changes in the mineral soil of Lithic Leptosols (Skeltic), whereas a significant reduction of Pb concentrations in their forest floors occurred. Reductions of concentrations in the less heterogeneous Cambisols (Chromic) were significant. In contrast, virtually no migration of Pb and Cd were found in Stagnosols due to their impeded drainage. Very low element concentrations (<1 mug l{sup -1}) in field-collected soil solutions using tension lysimeters (0.2 mum nylon filters) imply that migration largely occurred by preferential flow as particulate-bound species during intensive rainfall events. Our results indicate that the extent of Pb and Cd migration in soils is largely influenced by soil type. - Comparison between soil solid phase and soil solution concentrations imply that trace element migration largely occurred by preferential flow as particulate-bound species.

  5. [Strengthening health literacy of people with migration background: results of a qualitative evaluation].

    Science.gov (United States)

    Horn, Annett; Vogt, Dominique; Messer, Melanie; Schaeffer, Doris

    2015-06-01

    The concept of "health literacy", which has gained attention in English-speaking countries during the last decade, is becoming increasingly popular in Germany. While studies on an international level indicate that people with migration background are often limited in their health literacy, there is a lack of empirical data on that topic in Germany. However, it is well known that they are exposed to health-related risks and problems comparatively often whereas they use health care services less frequently. This article focuses on the native speaking counseling services of the Independent Patient Counseling Germany (UPD gGmbH) as an example of good practice and introduces the results of the evaluation of this counseling service. Qualitative interviews were conducted with UPD-consultants as well as with users of the services. It became apparent that Turkish and Russian-speaking immigrants often have limited health-related literacy. Therefore, support and counseling services should focus not only on issues concerning language and cultural aspects. Furthermore, strategies strengthening the health literacy of persons with migration background are required. Therefore, instruments and strategies will be developed in cooperation with the UPD which aim to improve such skills of the UPD-consultants.

  6. Synthetic seismic monitoring using reverse-time migration and Kirchhoff migration for CO2 sequestration in Korea

    Science.gov (United States)

    Kim, W.; Kim, Y.; Min, D.; Oh, J.; Huh, C.; Kang, S.

    2012-12-01

    During last two decades, CO2 sequestration in the subsurface has been extensively studied and progressed as a direct tool to reduce CO2 emission. Commercial projects such as Sleipner, In Salah and Weyburn that inject more than one million tons of CO2 per year are operated actively as well as test projects such as Ketzin to study the behavior of CO2 and the monitoring techniques. Korea also began the CCS (CO2 capture and storage) project. One of the prospects for CO2 sequestration in Korea is the southwestern continental margin of Ulleung basin. To monitor the behavior of CO2 underground for the evaluation of stability and safety, several geophysical monitoring techniques should be applied. Among various geophysical monitoring techniques, seismic survey is considered as the most effective tool. To verify CO2 migration in the subsurface more effectively, seismic numerical simulation is an essential process. Furthermore, the efficiency of the seismic migration techniques should be investigated for various cases because numerical seismic simulation and migration test help us accurately interpret CO2 migration. In this study, we apply the reverse-time migration and Kirchhoff migration to synthetic seismic monitoring data generated for the simplified model based on the geological structures of Ulleung basin in Korea. Synthetic seismic monitoring data are generated for various cases of CO2 migration in the subsurface. From the seismic migration images, we can investigate CO2 diffusion patterns indirectly. From seismic monitoring simulation, it is noted that while the reverse-time migration generates clear subsurface images when subsurface structures are steeply dipping, Kirchhoff migration has an advantage in imaging horizontal-layered structures such as depositional sediments appearing in the continental shelf. The reverse-time migration and Kirchhoff migration present reliable subsurface images for the potential site characterized by stratigraphical traps. In case of

  7. Probabilistic migration modelling focused on functional barrier efficiency and low migration concepts in support of risk assessment.

    Science.gov (United States)

    Brandsch, Rainer

    2017-10-01

    Migration modelling provides reliable migration estimates from food-contact materials (FCM) to food or food simulants based on mass-transfer parameters like diffusion and partition coefficients related to individual materials. In most cases, mass-transfer parameters are not readily available from the literature and for this reason are estimated with a given uncertainty. Historically, uncertainty was accounted for by introducing upper limit concepts first, turning out to be of limited applicability due to highly overestimated migration results. Probabilistic migration modelling gives the possibility to consider uncertainty of the mass-transfer parameters as well as other model inputs. With respect to a functional barrier, the most important parameters among others are the diffusion properties of the functional barrier and its thickness. A software tool that accepts distribution as inputs and is capable of applying Monte Carlo methods, i.e., random sampling from the input distributions of the relevant parameters (i.e., diffusion coefficient and layer thickness), predicts migration results with related uncertainty and confidence intervals. The capabilities of probabilistic migration modelling are presented in the view of three case studies (1) sensitivity analysis, (2) functional barrier efficiency and (3) validation by experimental testing. Based on the predicted migration by probabilistic migration modelling and related exposure estimates, safety evaluation of new materials in the context of existing or new packaging concepts is possible. Identifying associated migration risk and potential safety concerns in the early stage of packaging development is possible. Furthermore, dedicated material selection exhibiting required functional barrier efficiency under application conditions becomes feasible. Validation of the migration risk assessment by probabilistic migration modelling through a minimum of dedicated experimental testing is strongly recommended.

  8. 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...

  9. Cloud Security Audit for Migration and Continuous Monitoring

    OpenAIRE

    Ismail, Umar Mukhtar; Islam, Shareeful; Mouratidis, Haralambos

    2015-01-01

    Security assurance in cloud computing is one of the main barriers for wider cloud adoption. Potential cloud computing consumers like to know whether the controls in cloud environments can adequately protect critical assets migrated into the cloud. We present a cloud security audit approach to enable users' evaluate cloud service provider offerings before migration, as well as monitoring of events after migration. Our approach entails a set of concepts such as actor, goals, monitoring, conditi...

  10. Prestack exploding reflector modeling and migration in TI media

    KAUST Repository

    Wang, H.

    2014-01-01

    Prestack depth migration in anisotropic media, especially those that exhibit tilt, can be costly using reverse time migration (RTM). We present two-way spectral extrapolation of prestack exploding reflector modeling and migration (PERM) in acoustic transversely isotropic (TI) media. We construct systematic ways to evaluate phase angles and phase velocities in dip oriented TI (DTI), vertical TI (VTI) and tilted TI (TTI) media. Migration results from the Marmousi VTI model and the BP2007 TTI model show the feasibility of our approach.

  11. Application of the Poisson-Nernst-Planck equations to the migration test

    DEFF Research Database (Denmark)

    Krabbenhøft, Kristian; Krabbenhøft, Jørgen

    2008-01-01

    The Poisson-Nernst-Planck (PNP) equations are applied to model the migration test. A detailed analysis of the equations is presented and the effects of a number of common, simplifying assumptions are quantified. In addition, closed-form solutions for the effective chloride diffusivity based...... on the full PNP equations are derived, a number of experiments are analyzed in detail, and a new, truly accelerated migration test is proposed. Finally, we present a finite element procedure for numerical solution of the PNP equations....

  12. Iodine and selenium migration through argillaceous rocks

    International Nuclear Information System (INIS)

    Frasca, Benjamin

    2011-01-01

    Deep argillaceous formations are considered as potential host rock for high-level radioactive waste repository. Based on safety assessment calculations, active selenium ( 79 Se) and iodine ( 129 I) from high level radioactive waste might be ones of the major dose contributors due to their longevity and their anionic character. However, because of their high sensitivity to redox condition, a special attention to the oxidation state of these elements is required. A comparative study on the diffusion properties of selenium and iodine through argillaceous rocks was realized with the aim to determine the effects of both the redox conditions and the mineralogy on the migration of these two elements. For these purposes, we have studied two argillaceous rocks: Toarcian argillite from Tournemire (France) and Opalinus clay (OPA) from the Mont-Terri (Switzerland). The study of the iodide migration allowed to confirm the control on the iodide retention of both oxidized pyrite and natural organic matter. A kinetic control of the iodide sorption is also suspected. We focus the selenium study on the more oxidized species, Se(IV) and Se(VI). The Se(IV) migration is strongly dependant from oxido-reduction processes. Indeed, the Se(IV) diffusion experiments through Tournemire argillite and OPA indicated a significant reduction associated to Fe(II). The Se(VI) study evidenced a behavior dependant from the initial concentration: at the highest concentration, no significant retention was observed while the retention is significant at the lowest concentration. Furthermore, spectroscopic analyses tend to show a low Se(VI) reduction at the Fe contact. However, biotic origin cannot be excluded. (author)

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

    Science.gov (United States)

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

    2018-02-19

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

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

    International Nuclear Information System (INIS)

    Tanaka, Yukihisa; Hironaga, Michihiko

    2014-01-01

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

  15. Evaluation of 137 Cs in Chernobyl landscapes: mapping surface migration balance as background for application of rehabilitation technologies

    International Nuclear Information System (INIS)

    Davydchuk, V.; Arapis, G.

    1995-01-01

    This work includes two maps of balance evaluation of 137 Cs horizontal migration in natural landscapes of Chernobyl zone. The first map shows the short-term balance, which reflects the evaluation of 137 Cs migration from present up to 20-30 years in future. the second map refers to the kong-term balance and represents a forecast of the radioecological situation 60-80 years from the accident. On the base of our evaluation the territory of 30-km zone of Chernobyl Nuclear Power Plant can be divided in three parts, approximately equal but slightly differentiated in time. In fact, the landscape of extreme-morainic ridge of Christogalovka presents a clear negative balance of 137 Cs both in short-term and in long-term aspects. Landscapes with negative balance of the 137 Cs occupy for short-term about 37 % and for long-term 41 % of the investigated territory. Neutral balance is expected for short- and long-term to be approximately 39 % and 35 % of the territory respectively. Positive balance is expected for approx. 24 % of the territory in both terms. The proposed evaluations are qualitative and they can be used as background for preparation of any decisions related to the application of decontamination technologies and its ecological consequences

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

    CSIR Research Space (South Africa)

    Vogel

    1999-07-01

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

  17. Value assignment and uncertainty evaluation for single-element reference solutions

    Science.gov (United States)

    Possolo, Antonio; Bodnar, Olha; Butler, Therese A.; Molloy, John L.; Winchester, Michael R.

    2018-06-01

    A Bayesian statistical procedure is proposed for value assignment and uncertainty evaluation for the mass fraction of the elemental analytes in single-element solutions distributed as NIST standard reference materials. The principal novelty that we describe is the use of information about relative differences observed historically between the measured values obtained via gravimetry and via high-performance inductively coupled plasma optical emission spectrometry, to quantify the uncertainty component attributable to between-method differences. This information is encapsulated in a prior probability distribution for the between-method uncertainty component, and it is then used, together with the information provided by current measurement data, to produce a probability distribution for the value of the measurand from which an estimate and evaluation of uncertainty are extracted using established statistical procedures.

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

    International Nuclear Information System (INIS)

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

    1997-01-01

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

  19. Rare earth elements during diagenesis of abyssal sediments: analogies with a transuranic element americium

    International Nuclear Information System (INIS)

    Boust, D.

    1987-03-01

    One of the possibilities for the storage of high-level radioactive wastes consists in burying them into abyssal sediments, the sediments being supposed to barrier out radionuclides migration. The objective of the work was to estimate the efficiency of sediment barrier with respect to americium. As there is no americium in abyssal sediments, an indirect approach was used: the behaviour of the rare earth elements, the best natural analogs of americium. They were analysed in a 15 m long core, from the Cap Verde abyssal plateau. The terrigenous phase derived from the African continent was modified by short-term processes (1-1000 years); the intermediate rare earth elements were dissolved. Mineral coatings, enriched in rare earth appeared. After burial, the evolution continued at a much slower rate (10 5 - 10 6 years). The rare elements of the mineral coatings derived from the dissolution of the terrigenous phase and from an additional source, deeper in the sediment column. The fluxes of rare earth elements from sediment to water column were estimated. In suboxic sediments, the dissolved particulate equilibrium was related to redox conditions. The short-term reactivity of americium was studied in laboratory experiments. Simple americium migration models showed that the sediments barrier was totally efficient with respect to americium. In the conditions, neptunium 237 a daughter product of americium 241 could induce fluxes of 10 16 atoms per year per ton of stored waste (10 -8 Ci y-1), during millions years, towards the water column [fr

  20. The evaluation of the effects of buffer thickness and dry density on radionuclides migration in engineered barrier system

    International Nuclear Information System (INIS)

    Kato, Fujitaka; Ishihara, Yoshinao; Makino, Hitoshi; Ishiguro, Katsuhiko

    2000-01-01

    The evaluation of the effects of buffer thickness and dry density, one of the buffer design, on radionuclides migration behavior is important from the viewpoint of performance assessment since they have relation to radionuclides migration retardation. It is also considered to help investigation of buffer design that satisfy both safety and economy to condition of the disposal site, which may be required with development of disposal project in the future. Therefore we have performed a sensitivity analysis used buffer thickness and dry density as parameter and considered their combination in this report. Based on this, we have evaluated the effects of buffer thickness and dry density on radionuclides migration in engineered barrier system. And, we have considered about radionuclides migration retardation quality of the buffer which is based on the design (relationship between thickness and dry density) set in the second progress report on research and development for the geological disposal of HLW in Japan. In results, the maximum release rates from the engineered barrier system for the nuclides which have high distribution coefficients and short half lives are sensitive to changes in buffer thickness and dry density. And, using dose converted from the nuclide release rates from the engineered barrier system as a convenient index, it is almost shown that the maximum of total dose is less than 10 μ Sv/y in the cases which buffer thickness and dry density are based on the buffer design set in the second progress report on research and development for the geological disposal of HLW in Japan. These can be used as an information when design of buffer thickness and dry density is set by synthetically judgement of balance of safety and economy. (author)

  1. Data and methods in the environment-migration nexus

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  2. 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)

  3. Evaluation of Dark Spots Formated on the High Temperature Metal Filter Elements

    International Nuclear Information System (INIS)

    Park, Seung Chul; Hwang, Tae Won; Moon, Chan Kook

    2008-01-01

    Metal filter elements were newly introduced to the high temperature filter (HTF) system in the low- and intermediate-level radioactive waste vitrification plant. In order to evaluate the performance of various metal materials as filter media, elements made of AISI 316L, AISI 904L, and Inconel 600 were included to the test set of filter elements. At the visual inspection to the elements performed after completion of each test, a few dark spots were observed on the surface of some elements. Especially they were found much more at the AISI 316L elements than others. To check the dark spots are the corrosion phenomena or not, two kinds of analyses were performed to the tested filter elements. Firstly, the surfaces or the cross sections of filter specimens cut out from both normal area and dark spot area of elements were analyzed by SEM/EDS. The results showed that the dark spots were not evidences of corrosion but the deposition of sodium, sulfur and silica compounds volatilized from waste or molten glass. Secondly, the ring tensile strength were analyzed for the ring-shape filter specimens cut out from each kind of element. The result obtained from the strength tested showed no evidence of corrosion as well. Conclusionally, depending on the two kinds of analysis, no evidences of corrosion were found at the tested metal filter elements. But the dark spots formed on the surface could reduce the effective filtering area and increase the overall pressure drop of HTF system. Thus, continuous heating inside filter housing up to dew point will be required normally. And a few long-period test should be followed for the exact evaluation of corrosion of the metal filter elements.

  4. Developments in Education and International Migrations in New Member States of the EU

    OpenAIRE

    Kultalahti, Olli

    2013-01-01

    The paper examines the development of education systems and international migrations in selected new Member States. The countries are Estonia, the Czech Republic and Slovakia. The paper focuses on various elements in the development of education systems making people able to cope with competition on global labour markets. The outcomes of these developments largely regulate the supply of labour and consequently its international demand. Some statistics on international migration and integratio...

  5. 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.

  6. Coherence measures in automatic time-migration velocity analysis

    International Nuclear Information System (INIS)

    Maciel, Jonathas S; Costa, Jessé C; Schleicher, Jörg

    2012-01-01

    Time-migration velocity analysis can be carried out automatically by evaluating the coherence of migrated seismic events in common-image gathers (CIGs). The performance of gradient methods for automatic time-migration velocity analysis depends on the coherence measures used as the objective function. We compare the results of four different coherence measures, being conventional semblance, differential semblance, an extended differential semblance using differences of more distant image traces and the product of the latter with conventional semblance. In our numerical experiments, the objective functions based on conventional semblance and on the product of conventional semblance with extended differential semblance provided the best velocity models, as evaluated by the flatness of the resulting CIGs. The method can be easily extended to anisotropic media. (paper)

  7. Measured and evaluated neutron cross sections of elemental bismuth

    International Nuclear Information System (INIS)

    Smith, A.; Guenther, P.; Smith, D.; Whalen, J.; Howerton, R.

    1980-04-01

    Neutron total cross sections of elemental bismuth are measured with broad resolution from 1.2 to 4.5 MeV to accuracies of approx. = 1%. Neutron-differential-elastic-scattering cross sections of bismuth are measured from 1.5 to 4.0 MeV at incident neutron energy intervals of approx.< 0.2 MeV over the scattered-neutron angular range approx. = 20 to 160 deg. Differential neutron cross sections for the excitation of observed states in bismuth at 895 +- 12, 1606 +- 14, 2590 +- 15, 2762 +- 29, 3022 +- 21, and 3144 +- 15 keV are determined at incident neutron energies up to 4.0 MeV. An optical-statistical model is deduced from the measured values. This model, the present experimental results, and information available elsewhere in the literature are used to construct a comprehensive evaluated nuclear data file for elemental bismuth in the ENDF format. The evaluated file is particularly suited to the neutronic needs of the fusion-fission hybrid designer. 87 references, 10 figures, 6 tables

  8. Evaluating predictors of local dabbling duck abundance during migration: Managing the spectrum of conditions faced by migrants

    Science.gov (United States)

    Aagaard, Kevin; Crimmins, Shawn M.; Thogmartin, Wayne E.; Tavernia, Brian G.; Lyons, James E.

    2015-01-01

    The development of robust modelling techniques to derive inferences from large-scale migratory bird monitoring data at appropriate scales has direct relevance to their management. The Integrated Waterbird Management and Monitoring programme (IWMM) represents one of the few attempts to monitor migrating waterbirds across entire flyways using targeted local surveys. This dataset included 13,208,785 waterfowl (eight Anas species) counted during 28,000 surveys at nearly 1,000 locations across the eastern United States between autumn 2010 and spring 2013 and was used to evaluate potential predictors of waterfowl abundance at the wetland scale. Mixed-effects, log-linear models of local abundance were built for the Atlantic and Mississippi flyways during spring and autumn migration to identify factors relating to habitat structure, forage availability, and migration timing that influence target dabbling duck species abundance. Results indicated that migrating dabbling ducks responded differently to environmental factors. While the factors identified demonstrated a high degree of importance, they were inconsistent across species, flyways and seasons. Furthermore, the direction and magnitude of the importance of each covariate group considered here varied across species. Given our results, actionable policy recommendations are likely to be most effective if they consider species-level variation within targeted taxonomic units and across management areas. The methods implemented here can easily be applied to other contexts, and serve as a novel investigation into local-level population patterns using data from broad-scale monitoring programmes.

  9. Migrating to learn and learning to migrate: a study of the experiences and intentions of international student migrants.

    Science.gov (United States)

    Li, F L; Findlay, A M; Jowett, A J; Skeldon, R

    1996-03-01

    "The research reported here evaluates whether students come to the UK mainly for educational reasons, and therefore perceive their stay as temporary, or whether emigration for study is being used as part of a conscious strategy by people intending to become future labour migrants.... The simplest interpretation of the results appears to be that migration, experienced as a result of international moves for study purposes, does not influence planning of further migration moves. But the research also indicates that migration for education is closely tied to other types of population redistribution and should be treated by population geographers as an integral part of international migration systems." Data were collected by questionnaire survey from 349 engineering students at Hong Kong universities and 82 Hong Kong students studying engineering in the UK. excerpt

  10. Fibroblasts are in a position to provide directional information to migrating neutrophils during pneumonia in rabbit lungs.

    Science.gov (United States)

    Behzad, A R; Chu, F; Walker, D C

    1996-05-01

    Previous findings have shown that pulmonary fibroblasts are associated with preexisting holes in the endothelial and epithelial basal laminae through which neutrophils appear to enter and leave the interstitium as they migrate from capillaries to alveoli. To determine their role in neutrophil migration, fibroblast organization within the interstitium was assessed by transmission electron microscope observations of serial-sectioned rabbit lung tissue. Interstitial fibroblasts were found to physically interconnect the endothelial basal lamina holes to epithelial basal lamina holes. Morphometric assessment of rabbit lung tissue instilled with Streptococcus pneumoniae revealed that approximately 70% of the surface area density of migrating neutrophils is in close contact (15 nm or less) with interstitial fibroblasts and extracellular matrix elements (30 and 40%, respectively). Although migrating neutrophils were close enough to adhere to both fibroblasts and extracellular elements, the interstitial fibroblasts are organized in a manner that would allow them to provide directional information to the neutrophils. A model illustrating this process is proposed.

  11. Evaluation of the fuel-element assembly non-hermeticity at its early stage

    International Nuclear Information System (INIS)

    Bliznyakova, V.A.; Shevel', V.N.; Ostapenko, V.I.

    1983-01-01

    The given paper deals with control of the fuel-element assembly shell state at the early stage of failure development. Technique for the fuel-element assembly shell state evaluation are described. A method for assembly failure detection, used at WWR of the Institute for Nuclear Research is described also

  12. Trace elements partitioning during coal combustion in fluidized bed under O{sub 2}/CO{sub 2} atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Li, Haixin; Zhao, Changsui; Liang, Cai; Duan, Lunbo; Chen, Huichao [Southeast Univ., Nanjing (China). School of Energy and Environment

    2013-07-01

    Experiments were conducted to investigate the effects of temperature and O{sub 2}/CO{sub 2} atmosphere on trace elements (Cr, Mn, Co, Ni, Cd, Pb, Hg, As, Se) partitioning during combustion of Xuzhou bituminous coal in a 6 kWth fluidized bed. Inductively coupled plasma mass spectrometry (ICP-MS) and atomic fluorescence spectrometry (AFS) were used to determine trace elements contents in raw coal, bottom ash, fly ash and flue gas. The results indicate that with bed temperature increase, the relative enrichment of all the trace elements except Cr in bottom ash decreases suggesting that their volatility is enhanced. The relative enrichments of hardly volatile elements, like Cr and Mn in fly ash increase with bed temperature increase while those of partially volatile and highly volatile elements in fly ash are opposite. The relative enrichments of trace elements except Cr and Mn in fly ash are higher than those in bottom ash. Increasing bed temperature promotes elements like As, Se and Hg to migrate to vapor phase, Mn to migrate to fly ash and Cr to migrate to both bottom ash and fly ash. 21%O{sub 2}/79%CO{sub 2} atmosphere improves the volatility of Cr, Mn, Co, Se and their migration to fly ash, while restrains the volatility of As, Ni, Pb. It has little effect on the volatility of Hg but improves its migration to fly ash. Mass balance ratio was also calculated to observe trace elements distribution in bottom ash, fly ash and flue gas. There is no much difference in trace elements distribution between the two atmospheres. It can be seen that the trace elements proportion in fly ash is much greater, and more than 40% of Hg is distributed in the gas phase. Most of Hg and Se volatilize during combustion. The mass balance ratios are 87 {proportional_to} 129% which is considered acceptable.

  13. Supplemental feeding alters migration of a temperate ungulate.

    Science.gov (United States)

    Jones, Jennifer D; Kauffman, Matthew J; Monteith, Kevin L; Scurlock, Brandon M; Albeke, Shannon E; Cross, Paul C

    Conservation of migration requires information on behavior and environmental determinants. The spatial distribution of forage resources, which migration exploits, often are altered and may have subtle, unintended consequences. Supplemental feeding is a common management practice, particularly for ungulates in North America and Europe, and carryover effects on behavior of this anthropogenic manipulation of forage are expected in theory, but have received limited empirical evaluation, particularly regarding effects on migration. We used global positioning system (GPS) data to evaluate the influence of winter feeding on migration behavior of 219 adult female elk (Cervus elaphus) from 18 fed ranges and 4 unfed ranges in western Wyoming. Principal component analysis revealed that the migratory behavior of fed and unfed elk differed in distance migrated, and the timing of arrival to, duration on, and departure from summer range. Fed elk migrated 19.2 km less, spent 11 more days on stopover sites, arrived to summer range 5 days later, resided on summer range 26 fewer days, and departed in the autumn 10 days earlier than unfed elk. Time-to-event models indicated that differences in migratory behavior between fed and unfed elk were caused by altered sensitivity to the environmental drivers of migration. In spring, unfed elk migrated following plant green-up closely, whereas fed elk departed the feedground but lingered on transitional range, thereby delaying their arrival to summer range. In autumn, fed elk were more responsive to low temperatures and precipitation events, causing earlier departure from summer range than unfed elk. Overall, supplemental feeding disconnected migration by fed elk from spring green-up and decreased time spent on summer range, thereby reducing access to quality forage. Our findings suggest that ungulate migration can be substantially altered by changes to the spatial distribution of resources, including those of anthropogenic origin, and that

  14. Supplemental feeding alters migration of a temperate ungulate

    Science.gov (United States)

    Jones, Jennifer D; Kauffman, Matthew J.; Monteith, Kevin L.; Scurlock, Brandon M.; Albeke, Shannon E.; Cross, Paul C.

    2014-01-01

    Conservation of migration requires information on behavior and environmental determinants. The spatial distribution of forage resources, which migration exploits, often are altered and may have subtle, unintended consequences. Supplemental feeding is a common management practice, particularly for ungulates in North America and Europe, and carryover effects on behavior of this anthropogenic manipulation of forage are expected in theory, but have received limited empirical evaluation, particularly regarding effects on migration. We used global positioning system (GPS) data to evaluate the influence of winter feeding on migration behavior of 219 adult female elk (Cervus elaphus) from 18 fed ranges and 4 unfed ranges in western Wyoming. Principal component analysis revealed that the migratory behavior of fed and unfed elk differed in distance migrated, and the timing of arrival to, duration on, and departure from summer range. Fed elk migrated 19.2 km less, spent 11 more days on stopover sites, arrived to summer range 5 days later, resided on summer range 26 fewer days, and departed in the autumn 10 days earlier than unfed elk. Time-to-event models indicated that differences in migratory behavior between fed and unfed elk were caused by altered sensitivity to the environmental drivers of migration. In spring, unfed elk migrated following plant green-up closely, whereas fed elk departed the feedground but lingered on transitional range, thereby delaying their arrival to summer range. In autumn, fed elk were more responsive to low temperatures and precipitation events, causing earlier departure from summer range than unfed elk. Overall, supplemental feeding disconnected migration by fed elk from spring green-up and decreased time spent on summer range, thereby reducing access to quality forage. Our findings suggest that ungulate migration can be substantially altered by changes to the spatial distribution of resources, including those of anthropogenic origin, and that

  15. Deposition of radionuclides and stable elements in Tokai-mura

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Takashi; Amano, Hikaru [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    This report presents the data of deposition of radionuclides (Sep. 1993-March 2001) and stable elements (Sep. 1993-Oct. 1995) in Tokai-mura. To evaluate the migration of radionuclides and stable elements from the atmosphere to the ground surface, atmospheric deposition samples were collected from Sep. 1993 to March 2001 with three basins (distance to grand surface were 1.5 m, 4 m, 10 m) set up in the enclosure of JAERI in Tokai-mura, Ibaraki-ken, Japan. Monthly samples were evaporated to dryness to obtain residual samples and measured with a well type Ge detector for {sup 7}Be, {sup 40}K, {sup 137}Cs and {sup 210}Pb. According to the analysis of radioactivity, clear seasonal variations with spring peaks of deposition weight (dry) and deposition amounts of all objective radionuclides were found. Correlation analysis of deposition data also showed that these radionuclides can be divided into two groups. A part of dried sample was irradiated to reactor neutrons at JRR-4 for determination of stable element's deposition. (author)

  16. The role of family network in circular migration and formation of transnational communities

    DEFF Research Database (Denmark)

    Rezaei, Shahamak; Marques, Denise Helena França

    2016-01-01

    The complexity of family arrangements that constitute the return migration of Brazilians from Paraguay can be identified as an important element in maintaining the circularity between the two countries and the consolidation of transnational space Brasiguaio. This paper describes the changes in vo....... Information from the Brazilian Demographic Censuses of 1991, 2000 and 2010 will be used to do so, and to estimate the direct and indirect effects of international migration return to that country....

  17. Evaluation of some trace elements (zinc, chromium, cadmium and ...

    African Journals Online (AJOL)

    Throughout the world, tuberculosis (TB) infection is on the increase and it has remained one of the most important causes of death among adults in developing countries. This study evaluated the serum concentrations of some trace elements -Zinc (Zn), Manganese (Mn), Chromium (Cr) and Cadmium (Cd), in 100 blood ...

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

    Science.gov (United States)

    Weinstein, R I; Evans, R D

    1980-01-01

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

  19. Introduction of a method for determining uranium isotope ratio by α-spectroscopy and application to study the migration of this element in uranium occurence

    International Nuclear Information System (INIS)

    Bastos, K.F.

    1981-01-01

    A method of U and Th isotope ratio determination by α-spectroscopy to analyse the migration process of these elements at an uranium bearing region in Goias, Brazil, is described. The method consists of simultaneous extraction of U and Th with TOPO/cyclohexane, reextraction of Th with H 2 SO 4 (0.3M) and further purification of both phases. The interferent coextracted ions are eliminated by scrubbing with EDTA/NaNO 3 , and pure U is extracted with (NH 4 ) 2 CO 3 . The counting sources are prepared via extraction with TTA or MIBK, and evaporation of suitable aliquots on stainless steel disks. The recovery of U about 98% is obtained. The energy resolutions of U 238 peak (E α =4.195 MeV) are 52 and 83 KeV. The counting efficiencies are between 11 and 21+. Th is separated from the stripping solution by direct coprecipitation with macro amounts of LaF 3 and subsequent extraction with TTA/benzene for source preparation. Alternatively coprecipitation is proposed with micro quantities of LaF 3 and posterior filtration with membrane filters, where LaF 3 layer was previously deposited. This method allows direct counting of the filters and is superior in relation to energy resolution and counting efficiency. The U 238 /U 234 and U 234 /Th 230 isotope ratios in geological standards and prospecting samples were determined. The U 234 /Th 230 isotope ratio was used for analysing the migration of these elements because the most of analysed samples presented values, for this ratio, greater than unity, indicating that the anomalous concentrations of U are due to secondary enrichment processes. Aditional results of non equilibrium of the radioactivity of samples by γ-spectroscopy, are presented. (author) [pt

  20. Effects of seed migration on post-implant dosimetry of prostate brachytherapy

    International Nuclear Information System (INIS)

    Gao, M.; Wang, J. Z.; Nag, S.; Gupta, N.

    2007-01-01

    Brachytherapy using permanent seed implants has been an effective treatment for prostate cancer. However, seeds will migrate after implant, thus making the evaluation of post-implant dosimetry difficult. In this study, we developed a computer program to simulate seed migration and analyzed dosimetric changes due to seed migration at various migration amounts. The study was based on 14 patients treated with Pd-103 at the James Cancer Hospital. Modeling of seed migration, including direction, distance as well as day of migration, was based on clinical observations. Changes of commonly used dosimetric parameters as a function of migration amount (2, 4, 6 mm respectively), prostate size (from 20 to 90 cc), and prostate region (central vs peripheral) were studied. Change of biological outcome (tumor control probability) due to migration was also estimated. Migration reduced prostate D90 to 99±2% of original value in 2 mm migration, and the reduction increased to 94±6% in 6 mm migration. The reduction of prostate dose led to a 14% (40%) drop in the tumor control probability for 2 mm (6 mm) migration, assuming radiosensitive tumors. However, migration has less effect on a prostate implanted with a larger number of seeds. Prostate V100 was less sensitive to migration than D90 since its mean value was still 99% of original value even in 6 mm migration. Migration also showed a different effect in the peripheral region vs the central region of the prostate, where the peripheral mean dose tended to drop more significantly. Therefore, extra activity implanted in the peripheral region during pre-plan can be considered. The detrimental effects of migration were more severe in terms of increasing the dose to normal structures, as rectum V50 may be 70% higher and urethra V100 may be 50% higher in the case of 6 mm migration. Quantitative knowledge of these effects is helpful in treatment planning and post-implant evaluation

  1. Studies on Horizontal and Vertical Migration of 90Sr in Soil Systems

    International Nuclear Information System (INIS)

    Solecki, J.; Chibowski, S.

    2002-01-01

    Here are presented results of studies on vertical and horizontal migration of strontium 90 Sr isotope in soil systems of Bug river valleys. Mean radioactivity of strontium in these soils was 26.15 ± 22.2 Bq/kg. Atmospheric precipitation of strontium on this area was 0.35 kBq/m2/cm. Radioactivity in soil profiles ranged from 17 to 130 Bq/m2/cm and the isotope was detected even at 30 cm depth. Some tendency to vertical migration of strontium towards the river was noticed. Obtained results were compared with concentrations of calcium and strontium in the soil. Any clear influence of these elements on the migration of strontium 90 Sr was noticed. (author)

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

    Directory of Open Access Journals (Sweden)

    Maarja Saar

    2016-12-01

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

  3. Finite element evaluation of erosion/corrosion affected reducing elbow

    International Nuclear Information System (INIS)

    Basavaraju, C.

    1996-01-01

    Erosion/corrosion is a primary source for wall thinning or degradation of carbon steel piping systems in service. A number of piping failures in the power industry have been attributed to erosion/corrosion. Piping elbow is one of such susceptible components for erosion/corrosion because of increased flow turbulence due to its geometry. In this paper, the acceptability of a 12 in. x 8 in. reducing elbow in RHR service water pump discharge piping, which experienced significant degradation due to wall thinning in localized areas, was evaluated using finite element analysis methodology. Since the simplified methods showed very small margin and recommended replacement of the elbow, a detailed 3-D finite element model was built using shell elements and analyzed for internal pressure and moment loadings. The finite element analysis incorporated the U.T. measured wall thickness data at various spots that experienced wall thinning. The results showed that the elbow is acceptable as-is until the next fuel cycle. FEA, though cumbersome, and time consuming is a valuable analytical tool in making critical decisions with regard to component replacement of border line situation cases, eliminating some conservatism while not compromising the safety

  4. Fuel element tomography by gammametry

    International Nuclear Information System (INIS)

    Simonet, G.; Pineira, T.

    1982-03-01

    As from transversal gamma determinations of a cylindrical fuel element, the TOMOGAM program reconstitutes the distribution of fission products in a section. This direct, fast and non destructive method, makes it possible to have access to the behaviour of the fuel at any time: - the soluble fission products in the matrix represent the fuel itself and the distribution of the fissions, - the migrating elements inform on the temperature reached in accordance with the permitted powers, - the volatile nuclides build up in particular points where physical-chemical phenomena of fuel-cladding interaction are liable to corrode the latter. Hence, gamma spectrometry extends its possibilities of analysis relative to the performance of reactor elements [fr

  5. SL(C) 5 migration at CERN

    International Nuclear Information System (INIS)

    Schwickerath, Ulrich; Silva, Ricardo

    2010-01-01

    Most LCG sites are currently running on SL(C)4. However, this operating system is already rather old, and it is becoming difficult to get the required hardware drivers, to get the best out of recent hardware. A possible way out is the migration to SL(C)5 based systems where possible, in combination with virtualization methods. The former is typically possible for nodes where the software to run the services is available and tested, while the latter offers a possibility to make use of the new hardware platforms whilst maintaining operating system compatibility. Since autumn 2008, CERN has offered public interactive and batch worker nodes for evaluation to the experiments. For the Grid environment, access is granted by a dedicated CEs. The status of the evaluation, feedback received from the experiments and the status of the migration will be reviewed, and the status of virtualization of services at CERN will be reported. Beyond this, the migration to a new operating system also offers an excellent opportunity to upgrade the fabric infrastructure used to manage the servers.

  6. MIGRATION '03: 9th International Conference on Chemistry and Migration Behavior of Actinides and Fission Products in the Geosphere

    International Nuclear Information System (INIS)

    Kim, Geon Young; Hahn, Pil Soo; Kang, Moon Ja; Baik, Min Hoon; Kim, Seung

    2003-12-01

    The objectives of this report are overview of the chemistry and migration behavior of actinide for the HLW disposal safety assessment and to summarise the present status of actinide science and future developments. Actinides in HLW are very toxic and long-life time radionuclides. Therefore, the understanding of their characteristics and reaction behaviors in the deep subsurface environment is necessary for improving the reliability of HLW disposal safety assessment. This report presents an overview of the recent developments in the fundamental chemistry of actinides and fission products in natural aquifer systems, their interactions and migration in the geosphere, and the processes involved in modeling their geochemical behavior for the high level radioactive waste management. In addition, the thesis presented in MIGRATION '03 conference were described briefly. Actinide science in relation to the HLW disposal management can be classified into three main subjects; aquatic chemistry of actinides and fission products, migration behavior of radionuclides and geochemical and transport modeling. The radionuclides leached from waste forms are intruded into human environment along the groundwater flowing in the fracture around the waster disposal facility. To analyze and predict such radionuclide migration phenomena, the data that were obtained from well defined condition are required. Data obtained from studies on the chemical behaviors of actinide elements and fission products in the groundwater are essential in the safety assessment of HLW management. This report is intended to suggest the direction of R and D in actinide chemistry for the national program of HLW management in future

  7. Rules for matrix element evaluations in JWKB approximation

    International Nuclear Information System (INIS)

    Giler, S.

    1990-01-01

    Using the properties of the so-called fundamental solutions to the one-dimensional Schroedinger equation having Froeman and Froeman form the rules are formulated which allow one to evaluate matrix elements in the JWKB approximation and its generalizations. The rules apply to operators M(x, d/dx), M being polynomial functions of their arguments. The applicability of the rules depends on the properties of the so-called canonical indices introduced in this paper. The canonical indices are global characteristics of underlying Stokes graphs. If sufficiently small in comparison with unity they allow one to apply safely the JWKB approximation within the so-called ε-reduced canonical domains of a given Stokes graph. The Oth canonical index for the nth energy level Stokes graph corresponding to the harmonic oscillator potential is found to be ε CAN = 0.678/(2n+1). If the application of the rules is allowed then approximated matrix elements are obtained in an unambiguous way and with an accuracy controlled by corresponding canonical indices. Several examples of matrix elements are considered to illustrate how the rules should be used. Limitations to the rules are also discussed with the aid of suitably chosen examples. (author)

  8. A remark on the effect f organic materials on the migration of {sup 90}Sr in the soil; Une remarque sur l'effet des matieres organiques dans la migration du {sup 90}Sr dans le sol

    Energy Technology Data Exchange (ETDEWEB)

    Gailledreau, C.

    1960-05-05

    After having presented different characteristics of the migration of iron in soils submitted to an intense leaching, and noticed that a similar process could be at the origin of the quick displacement of a radioactive contamination due to wastewater releases or fallouts, the author reports an experimental study performed by using one of the most hazardous radio-element, strontium 90, placed at the top of an earth column in which an anaerobic fermentation occurs. The strontium migration is compared with that in a similar column but without fermentation. Calcium migration and pH are measured. The migration behaviour of strontium appears to be very similar to that of calcium.

  9. 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.

  10. INSTRUMENT FOR EVALUATION OF THE ADAPTED ABILITIES FROM THE ELEMENT OF BASKETBALL TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Goran Šekeljić

    2006-06-01

    Full Text Available The idea of the work is clearly defined, precise and objective instrument for evaluation of the adopted abilities from the elements of basketball technique. The intention is to cut into small fragments the chosen elements of technique which are going to be evaluated with numerical value of every piece itself. The model established in that way is possible to compare with motorical forms acquired by those who are been inquired. Every fragment of motorical form has precise numerical value on which basis is possible to quantify by simple numerical total the obtained level of sports- technical education. We consider possible to diminish the influence of subjectivity such as to form schoolmarks more objectivly by precise and high-quality system of evaluation on the basis of clearly cut into small pieces structures of elements of the complete technique. In that case we could talk about real expert evaluation. The results of the research have shown that the method of evaluation conceived in this way has given excellent metrics characteristics and that, statistically verified, has been more objective than the two other methods predicted in the experiment

  11. GPU-accelerated Modeling and Element-free Reverse-time Migration with Gauss Points Partition

    Science.gov (United States)

    Zhen, Z.; Jia, X.

    2014-12-01

    Element-free method (EFM) has been applied to seismic modeling and migration. Compared with finite element method (FEM) and finite difference method (FDM), it is much cheaper and more flexible because only the information of the nodes and the boundary of the study area are required in computation. In the EFM, the number of Gauss points should be consistent with the number of model nodes; otherwise the accuracy of the intermediate coefficient matrices would be harmed. Thus when we increase the nodes of velocity model in order to obtain higher resolution, we find that the size of the computer's memory will be a bottleneck. The original EFM can deal with at most 81×81 nodes in the case of 2G memory, as tested by Jia and Hu (2006). In order to solve the problem of storage and computation efficiency, we propose a concept of Gauss points partition (GPP), and utilize the GPUs to improve the computation efficiency. Considering the characteristics of the Gaussian points, the GPP method doesn't influence the propagation of seismic wave in the velocity model. To overcome the time-consuming computation of the stiffness matrix (K) and the mass matrix (M), we also use the GPUs in our computation program. We employ the compressed sparse row (CSR) format to compress the intermediate sparse matrices and try to simplify the operations by solving the linear equations with the CULA Sparse's Conjugate Gradient (CG) solver instead of the linear sparse solver 'PARDISO'. It is observed that our strategy can significantly reduce the computational time of K and Mcompared with the algorithm based on CPU. The model tested is Marmousi model. The length of the model is 7425m and the depth is 2990m. We discretize the model with 595x298 nodes, 300x300 Gauss cells and 3x3 Gauss points in each cell. In contrast to the computational time of the conventional EFM, the GPUs-GPP approach can substantially improve the efficiency. The speedup ratio of time consumption of computing K, M is 120 and the

  12. Impact of Enhanced Health Interventions for United States-Bound Refugees: Evaluating Best Practices in Migration Health.

    Science.gov (United States)

    Mitchell, Tarissa; Lee, Deborah; Weinberg, Michelle; Phares, Christina; James, Nicola; Amornpaisarnloet, Kittisak; Aumpipat, Lalita; Cooley, Gretchen; Davies, Anita; Tin Shwe, Valerie Daw; Gajdadziev, Vasil; Gorbacheva, Olga; Khwan-Niam, Chutharat; Klosovsky, Alexander; Madilokkowit, Waritorn; Martin, Diana; Htun Myint, Naing Zaw; Yen Nguyen, Thi Ngoc; Nutman, Thomas B; O'Connell, Elise M; Ortega, Luis; Prayadsab, Sugunya; Srimanee, Chetdanai; Supakunatom, Wasant; Vesessmith, Vattanachai; Stauffer, William M

    2018-03-01

    With an unprecedented number of displaced persons worldwide, strategies for improving the health of migrating populations are critical. United States-bound refugees undergo a required overseas medical examination to identify inadmissible conditions (e.g., tuberculosis) 2-6 months before resettlement, but it is limited in scope and may miss important, preventable infectious, chronic, or nutritional causes of morbidity. We sought to evaluate the feasibility and health impact of diagnosis and management of such conditions before travel. We offered voluntary testing for intestinal parasites, anemia, and hepatitis B virus infection, to U.S.-bound refugees from three Thailand-Burma border camps. Treatment and preventive measures (e.g., anemia and parasite treatment, vaccination) were initiated before resettlement. United States refugee health partners received overseas results and provided post-arrival medical examination findings. During July 9, 2012 to November 29, 2013, 2,004 refugees aged 0.5-89 years enrolled. Among 463 participants screened for seven intestinal parasites overseas and after arrival, helminthic infections decreased from 67% to 12%. Among 118 with positive Strongyloides -specific antibody responses, the median fluorescent intensity decreased by an average of 81% after treatment. The prevalence of moderate-to-severe anemia (hemoglobin migration process to improve the health of refugees before resettlement. With more than 250 million migrants globally, this model may offer insights into healthier migration strategies.

  13. The CT and MR evaluation of migrational disorders of the brain. Pt. 1

    International Nuclear Information System (INIS)

    Byrd, S.E.; Osborn, R.E.; Bohan, T.P.; Texas Univ., Houston; Naidich, T.P.

    1989-01-01

    The migrational disorders are a rare group of congenital malformations of the brain. They consist of the following entities - lissencephaly (agyria-pachygyria), pachygyria, schizencephaly, heterotopia and polymicrogyria. We studied 40 children with migrational disorders radiologically with CT and MR. This article (part I) deals with our patients with lissencephaly and pachygyria. It emphasizes their characteristic CT and MR findings along with their clinical presentation and course. These patients presented with one or a combination of the following symptoms, hypotonia, seizures, failure to thrive, microcephaly and occasionally hydrocephalus. These two groups of migrational disorders have abnormalities affecting the gyral-sulcal pattern of the cortex and gray-white matter distribution of the brain. MR provided better delineation of these disorders than CT. Because some forms of the migrational disorders can be inherited, it is extremely important for the radiologist to understand the characteristic findings for correct diagnosis which is essential for parental counseling. (orig.)

  14. Enhancement of User Quality of Experience (QoE) for Service Migration in Context Aware Environment

    DEFF Research Database (Denmark)

    Saeed, Aamir

    condition, device resources utilization and user mobility may be outdated, and have potential to invoke an unnecessary migration which impacts the satisfaction level of user. Firstly, the work presented in this thesis propose a service migration framework (SMF) for designing application with migration...... decision for massively multiplayer online game server (MMOG) was simulated. Due to communication delay and load transfer delay, the shared context is often outdated, and may trigger unnecessary migration. A prediction based approach was presented, to use estimated future server state as additional context...... individual user responsiveness. In summary, the thesis identified core elements of migration process. The mapping of loss of user experience as QoE loss score value, provides a performance metric for measuring performance of migratory application. Furthermore, the impact of out dated information in dynamic...

  15. Managing International Migration for Development in East Asia

    OpenAIRE

    Adams, Richard H., Jr.; Ahsan, Ahmad

    2014-01-01

    The objective of this book is to analyze the economic and social impact of international migration on labor sending and labor receiving countries in the East Asia region. More specifically, the book seeks: (a) to examine the impact of international migration on key development indicators, including poverty, investment, labor force participation, labor productivity and wages; (b) to evaluate ...

  16. Grading system for migrated lumbar disc herniation on sagittal magnetic resonance imaging. An agreement study

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Y.; Jeong, T.S. [Gachon University Gil Medical Center, Department of Neurosurgery, Incheon (Korea, Republic of); Lim, T.; Jeon, J.Y. [Gachon University Gil Medical Center, Department of Radiology, Incheon (Korea, Republic of)

    2018-01-15

    Migrated lumbar disc herniations (LDHs) in the sagittal plane are common. Disc migration grading can be applied as a useful measurement tool in the diagnosis, treatment, and outcome evaluation of migrated LDH. No study has evaluated the reliability of migrated LDH grading. We evaluated the reliability and functionality of the current magnetic resonance imaging (MRI) grading system for migrated LDH. We assessed a six-level grading system developed based on sagittal MRI and graded according to the direction (rostral and caudal) and degree (low, high, and very high) of disc migration. One-hundred and one migrated LDHs treated with minimally invasive endoscopic discectomy were analyzed independently by two experienced radiologists. Intraobserver and interobserver agreements were assessed by kappa statistics. The most common migrated LDH grade was grade 4 (30.94%; caudal, low-grade migration). Rostral and caudal migrations were more common in the upper and lower lumbar levels, respectively. Interobserver agreement in the grading of migrated LDH was good at both the first (kappa = 0.737) and second assessment (kappa = 0.657). The intraobserver agreement for reader 1 was very good (kappa = 0.827) and for reader 2 was good (kappa = 0.620). The current grading system for migrated LDH was found to be reliable and functional with good interobserver and intraobserver agreement. It may be useful in the interpretation of disc migration patterns and outcomes of various minimally invasive surgical procedures. (orig.)

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

    Science.gov (United States)

    Fontanari, José F; Serva, Maurizio

    2014-03-01

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

  18. MIGRATION '03: 9th International Conference on Chemistry and Migration Behavior of Actinides and Fission Products in the Geosphere

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Geon Young; Hahn, Pil Soo; Kang, Moon Ja; Baik, Min Hoon; Kim, Seung

    2003-12-15

    The objectives of this report are overview of the chemistry and migration behavior of actinide for the HLW disposal safety assessment and to summarise the present status of actinide science and future developments. Actinides in HLW are very toxic and long-life time radionuclides. Therefore, the understanding of their characteristics and reaction behaviors in the deep subsurface environment is necessary for improving the reliability of HLW disposal safety assessment. This report presents an overview of the recent developments in the fundamental chemistry of actinides and fission products in natural aquifer systems, their interactions and migration in the geosphere, and the processes involved in modeling their geochemical behavior for the high level radioactive waste management. In addition, the thesis presented in MIGRATION '03 conference were described briefly. Actinide science in relation to the HLW disposal management can be classified into three main subjects; aquatic chemistry of actinides and fission products, migration behavior of radionuclides and geochemical and transport modeling. The radionuclides leached from waste forms are intruded into human environment along the groundwater flowing in the fracture around the waster disposal facility. To analyze and predict such radionuclide migration phenomena, the data that were obtained from well defined condition are required. Data obtained from studies on the chemical behaviors of actinide elements and fission products in the groundwater are essential in the safety assessment of HLW management. This report is intended to suggest the direction of R and D in actinide chemistry for the national program of HLW management in future.

  19. Eh-pH diagrams for elements from Z = 40 to Z = 52: application to the Oklo natural reactor, Gabon

    Energy Technology Data Exchange (ETDEWEB)

    Brookins, D G [New Mexico Univ., Albuquerque (USA). Dept. of Geology

    1978-11-01

    Eh-pH diagrams for elements from Z = 40 (Zr) to Z = 52 (Te) have been constructed in order to comment on migration/retention of these elements at Oklo. Although data for fissiogenic amounts of some of these elements are lacking, where such data are available to agreement between predicted migration/retention based on the Eh-pH diagrams and actual measurement is excellent. Based on Eh-pH diagrams, migration (to what degree is uncertain) of Mo and Cd is predicted whereas retention of Y, Zr, Tc, Ru, Rh, Pd, Ag and Te is also predicted. An earlier report of Frejacques et al. of Tc migration is in disagreement with Eh-pH prediction, and recent (unpublished) data argue for Tc retention. In view of the agreement between prediction and observation, the possible migration of Sb and retention of In and Sn is proposed. These data again demonstrate the usefulness of Eh-pH diagrams for the Oklo fossil nuclear reactor but, more important, allow constraints to be placed on repositories for nuclear waste now under consideration.

  20. Defect evolution and impurity migration in Na-implanted ZnO

    Science.gov (United States)

    Neuvonen, Pekka T.; Vines, Lasse; Venkatachalapathy, Vishnukanthan; Zubiaga, Asier; Tuomisto, Filip; Hallén, Anders; Svensson, Bengt G.; Kuznetsov, Andrej Yu.

    2011-11-01

    Secondary ion mass spectrometry (SIMS) and positron annihilation spectroscopy (PAS) have been applied to study impurity migration and open volume defect evolution in Na+ implanted hydrothermally grown ZnO samples. In contrast to most other elements, the presence of Na tends to decrease the concentration of open volume defects upon annealing and for temperatures above 600∘C, Na exhibits trap-limited diffusion correlating with the concentration of Li. A dominating trap for the migrating Na atoms is most likely Li residing on Zn site, but a systematic analysis of the data suggests that zinc vacancies also play an important role in the trapping process.

  1. Environmental and biological behaviour of plutonium and some other transuranium elements

    International Nuclear Information System (INIS)

    Richmond, C.R.

    1983-01-01

    The objectives are to summarize our knowledge of the way in which plutonium and some other transuranium elements migrate through ecosystems; to consider how the physiochemical state of these elements and the biological systems through which they pass may influence this movement; and to put into perspective the risks of serious illness in man resulting from his exposure to these elements in the environment

  2. Measured and evaluated fast neutron cross sections of elemental nickel

    International Nuclear Information System (INIS)

    Guenther, P.; Smith, A.; Smith, D.; Whalen, J.; Howerton, R.

    1975-07-01

    Fast neutron total and scattering cross sections of elemental nickel are measured. Differential elastic scattering cross sections are determined from incident energies of 0.3 to 4.0 MeV. The cross sections for the inelastic neutron excitation of states at: 1.156 +- 0.015, 1.324 +- 0.015, 1.443 +- 0.015, 2.136 +- 0.013, 2.255 +- 0.030, 2.449 +- 0.030, 2.614 +- 0.020 and 2.791 +- 0.025 MeV are measured to incident neutron energies of 4.0 MeV. The total neutron cross sections are determined from 0.25 to 5.0 MeV. The experimental results are discussed in the context of optical and statistical models. It is shown that resonance width-fluctuation and correlation effects are significant. The present experimental and theoretical results, together with previously reported values, are used to construct a comprehensive evaluated elemental data file in the ENDF format. Some comparisons are made with previously reported evaluated files. In addition, some selected reactions which are widely used in dosimetry and other applications are presented as supplemental evaluated isotopic-data files. The numerical quantities are presented in tabular form. (3 tables, 29 figures)

  3. A radiotracer technique for the migration of inorganic contaminants into dry food from packaging made from recycled paper and board

    International Nuclear Information System (INIS)

    Aston, D.S.J.; Parry, S.J.

    2005-01-01

    A radiotracer method, initially developed to analyze migration from retail plastic food packaging into food simulants, has been developed to assess the measurement of inorganic contaminants migrating from recycled paper and board into real food. This new radiotracer method has been applied to the study of 10 food samples and their corresponding recycled paper and board packaging. Samples of paper and board were irradiated in a thermal neutron flux of 1.26 x 10 16 n x m -2 x s -1 for 15 hours to activate elements of interest. After a decay period of 10 days the paper and board was placed in contact with the corresponding foodstuff. The food was analyzed for any radioactivity migrating from the packaging by gamma-ray spectrometry. Samples were analyzed regularly during the 90 days contact time. Detection limits for the determination of migration was as low as a few μg/kg in the food. Results from the migration study have shown that, of the 60 elements measured, only Zn and Fe were detected in food, at concentrations of 0.012-0.25, and 0.045-0.11 mg/kg, respectively. This was despite the recycled paper and board samples being highly elevated in many other elements such as Cr (0.9-15.1 mg/kg) and Ba (3.3-75.4 mg/kg). The level of migration of Zn and Fe into food from packaging was insignificant compared to the UK recommended daily allowances of 15 mg, and, therefore, represented no hazard to human health. (author)

  4. Evaluation of gas migration characteristics of compacted bentonite considering in-situ conditions of disposal facility

    International Nuclear Information System (INIS)

    Tanaka, Yukihisa; Hironaga, Michihiko

    2012-01-01

    In the current concept of repository for radioactive waste disposal, compacted bentonite will be used as an engineered barrier mainly for inhibiting migration of radioactive nuclides. Hydrogen gas can be generated inside the engineered barrier by anaerobic corrosion of metals used for containers, etc. If the gas generation rate exceeds the diffusion rate of 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 effect of gas pressure generation and gas migration on the engineered barrier, peripheral facilities and ground. CRIEPI already proposed an analytical method for simulating gas migration through the compacted bentonite using the model of two phase flow through deformable porous media. Though validity of the analytical code of CRIEPI was examined by comparing existing gas migration test results with the calculated results, further validation is needed because in situ conditions, such as stress conditions and boundary condition, are different from conventional laboratory gas migration tent. In this study, gas migration tests whose initial axial stress is larger than initial radial stress and gas migration tests whose gas inlet is small. Simulation of the test results is also conducted. Comparing the test results with the calculated results, it is revealed that the analytical code of CRIEPI can simulate gas migration behavior through compacted bentonite with accuracy. (author)

  5. PVC cling film in contact with cheese: health aspects related to global migration and specific migration of DEHA

    DEFF Research Database (Denmark)

    Petersen, Jens Højslev; Naamansen, Ebbe Tubæk; Nielsen, Preben Aagård

    1995-01-01

    experiment samples of cheese of the types most commonly consumed in Denmark were wrapped in this 'low migration' PVC film using a procedure simulating the actual pattern of use in retail shops. After a storage time of 2 h at 5 degrees C the level of DEHA was 45 mg/kg of cheese, which after 10 days increased...... of DEHA close to or above the tolerable daily intake of 0.3 mg/kg body weight as defined by the EEC Scientific Committee for Food. Furthermore, it is stressed that measurements of global migration followed by uncritical use of reduction factors may result in erroneous evaluation of the suitability of DEHA-plasticized......Following exposure to the food simulant olive oil for 10 days at 5, 20 or 40 degrees C a global migration ranging from 20 to 30 mg/dm(2) was detected from a common 'low migration' PVC film plasticized with a mixture of di-(ethylhexyl)adipate (DEHA) and a polymeric plasticizer. In a laboratory...

  6. ARDISC (Argonne Dispersion Code): computer programs to calculate the distribution of trace element migration in partially equilibrating media

    International Nuclear Information System (INIS)

    Strickert, R.; Friedman, A.M.; Fried, S.

    1979-04-01

    A computer program (ARDISC, the Argonne Dispersion Code) is described which simulates the migration of nuclides in porous media and includes first order kinetic effects on the retention constants. The code allows for different absorption and desorption rates and solves the coupled migration equations by arithmetic reiterations. Input data needed are the absorption and desorption rates, equilibrium surface absorption coefficients, flow rates and volumes, and media porosities

  7. European Integration, Labour Market Dynamics and Migration Flows

    Directory of Open Access Journals (Sweden)

    Martinoia, Michela

    2011-06-01

    Full Text Available The paper has two objectives. Firstly, we wish to evaluate whether a greater economic integration has effects, and of what type, on migration flows from Central and Eastern Europe (New Member States of the EU, NMS towards the fifteen countries of the European Union (EU-15. Secondly, we wish to understand what effect the migration flows from the NMS have on the labour market of the receiving countries in the EU-15. The most suitable theoretical context that seems to summarise European labour market characteristics is that of the insider/outsider model by Layard, Nickell and Jackman (Layard et al., 1991. We have modified the above mentioned model by introducing two innovations. Firstly, we constructed three measures that act as a proxy for economic integration: the Intra Regional Trade Index (IRTI, Global Trade Index (GTI and Financial Market Integration (FMI. Then we placed the three indicators into the insider/outsider model to arrive at a modified version of Layard, Nickell and Jackman (Layard et al., 1991. The second innovative contribution was the introduction of an equation modelling migration flows. The creation of this equation is inspired by the neo-classical approach to migration theory (Harris-Todaro, 1970. The theoretical model, based on rational expectations, has been solved to find the equilibrium solution and the impact multipliers. We then carried out an empirical analysis, which involved estimating a Structural Vector Autoregression Model (SVAR. The aim of this estimation was to evaluate, on the one hand, the effect that greater European integration (a positive shock to the integration indicators has on migration flows, and, on the other, to measure the type of effect that migration flows could have on the labour market of the EU-15 countries, considered as a single entity. The results of our empirical evidence show that economic integration does generate significant effects on migration flows from the enlargement countries

  8. Exploring the Role of Trade and Migrations in Nigeria-Ghana ...

    African Journals Online (AJOL)

    Of these facilitators of inter-group relations, the two most outstanding elements that defined their relations before and during the colonial period were trade and migrations. The basic theme of this paper is therefore to document the nature and form of this trade network facilitated largely by the Hausa's and Yoruba's of Nigeria ...

  9. Annual report for FY 1976 on project AN0115A: the 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.

    1976-12-01

    Studies have been carried out on the migration of plutonium and americium in solutions flowing through porous and crushed rock and through fissures. The migration process can be described in terms of the surface absorption of these elements. In addition, chemical effects on the absorption have been observed. One of these effects is possibly due to the presence of a plutonium polymer that migrates at a more rapid rate than normal plutonium

  10. Elemental composition of Tibetan Plateau top soils and its effect on evaluating atmospheric pollution transport

    International Nuclear Information System (INIS)

    Li Chaoliu; Kang Shichang; Zhang Qianggong

    2009-01-01

    The Tibetan Plateau (TP) is an ideal place for monitoring the atmospheric environment of low to mid latitudes. In total 54 soil samples from the western TP were analyzed for major and trace elements. Results indicate that concentrations of some typical 'pollution' elements (such as As) are naturally high here, which may cause incorrect evaluation for the source region of these elements, especially when upper continental crust values are used to calculate enrichment factors. Because only particles <20 μm are transportable as long distances, elemental concentrations of this fraction of the TP soils are more reliable for the future aerosol related studies over the TP. In addition, REE compositions of the TP soils are unusual, highly characteristic and can be used as an effective index for identifying dust aerosol from the TP. - High concentrations of some elements of the Tibetan soils can cause incorrect evaluation for the source region of these elements during aerosol related study.

  11. 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

  12. Burn up determination of IEAR-1 fuel elements by non destructive gamma ray spectrometry method

    International Nuclear Information System (INIS)

    Soares, A.J.

    1977-01-01

    Measurement of nuclear fuel burn up by non destructive gamma ray spectrometry is discussed, and results of such measurements, made at the Instituto de Energia Atomica (IEA), are given. Specifically, the burn up of an MTR (Material Testing Reactor) fuel element removed from the IEAR-1 swimming pool reactor in 1958 is evaluated from the measured Cs-137 activity, which gives a single 661,6 keV gamma ray. Due to the long decay time of the test element, no other fission decay product activity could be detected. Analysis of measurements, made with a 3'' x 3'' NaI(Tl) detector at 330 distinct points of the element, showed the total burn up to 3.3 +- -+ 0.8 mg. This is in agreement with a calculated value. As the maximum temperature of IEAR-1 fuel elements is of the order of 40 0 C, migration effects of Cs-137 was not considered, this being significant only at fuel temperature in excess of 1000 0 C [pt

  13. Performance evaluation of data center service localization based on virtual resource migration in software defined elastic optical network.

    Science.gov (United States)

    Yang, Hui; Zhang, Jie; Ji, Yuefeng; Tan, Yuanlong; Lin, Yi; Han, Jianrui; Lee, Young

    2015-09-07

    Data center interconnection with elastic optical network is a promising scenario to meet the high burstiness and high-bandwidth requirements of data center services. In our previous work, we implemented cross stratum optimization of optical network and application stratums resources that allows to accommodate data center services. In view of this, this study extends the data center resources to user side to enhance the end-to-end quality of service. We propose a novel data center service localization (DCSL) architecture based on virtual resource migration in software defined elastic data center optical network. A migration evaluation scheme (MES) is introduced for DCSL based on the proposed architecture. The DCSL can enhance the responsiveness to the dynamic end-to-end data center demands, and effectively reduce the blocking probability to globally optimize optical network and application resources. The overall feasibility and efficiency of the proposed architecture are experimentally verified on the control plane of our OpenFlow-based enhanced SDN testbed. The performance of MES scheme under heavy traffic load scenario is also quantitatively evaluated based on DCSL architecture in terms of path blocking probability, provisioning latency and resource utilization, compared with other provisioning scheme.

  14. 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...

  15. An evaluated neutronic data file for elemental cobalt

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, P.; Lawson, R.; Meadows, J.; Sugimoto, M.; Smith, A.; Smith, D.; Howerton, R.

    1988-08-01

    A comprehensive evaluated neutronic data file for elemental cobalt is described. The experimental data base, the calculational methods, the evaluation techniques and judgments, and the physical content are outlined. The file contains: neutron total and scattering cross sections and associated properties, (n,2n) and (n,3n) processes, neutron radiative capture processes, charged-particle-emission processes, and photon-production processes. The file extends from 10/sup /minus/5/ eV to 20 MeV, and is presented in the ENDF/B-VI format. Detailed attention is given to the uncertainties and correlations associated with the prominent neutron-induced processes. The numerical contents of the file have been transmitted to the National Nuclear Data Center, Brookhaven National Laboratory. 143 refs., 16 figs., 5 tabs.

  16. Overall and specific migration from multilayer high barrier food contact materials - kinetic study of cyclic polyester oligomers migration.

    Science.gov (United States)

    Úbeda, Sara; Aznar, Margarita; Vera, Paula; Nerín, Cristina; Henríquez, Luis; Taborda, Laura; Restrepo, Claudia

    2017-10-01

    Most multilayer high barrier materials used in food packaging have a polyurethane adhesive layer in their structures. In order to assess the safety of these materials, it is important to determine the compounds intentionally added to the adhesives (IAS) as well as those non-intentionally added substances (NIAS). During the manufacture of polyurethane adhesives, some by-products can be formed, such as cyclic polyester oligomers coming from the reaction between dicarboxylic acids and glycols. Since these compounds are not listed in the Regulation 10/2011/EU, they should not be found in migration above 0.01 mg/kg of simulant. In this study two flexible multilayer packaging materials were used and migration was evaluated in simulant A (ethanol 10% v/v), simulant B (acetic acid 3% w/v) and simulant ethanol 95% v/v during 10 days at 60ºC. Identification and quantification of non-volatile compounds was carried out by UPLC-MS-QTOF. Most of migrants were oligomers such as cyclic polyesters and caprolactam oligomers. Overall migration and specific migration of adipic acid-diethylene glycol and phthalic acid-diethylene glycol were monitored over time and analysed by UPLC-MS-TQ. In most cases, ethanol 95% v/v was the simulant with the highest concentration values. Overall migration kinetics followed a similar pattern than specific migration kinetics.

  17. A theoretical and empirical evaluation and extension of the Todaro migration model.

    Science.gov (United States)

    Salvatore, D

    1981-11-01

    "This paper postulates that it is theoretically and empirically preferable to base internal labor migration on the relative difference in rural-urban real income streams and rates of unemployment, taken as separate and independent variables, rather than on the difference in the expected real income streams as postulated by the very influential and often quoted Todaro model. The paper goes on to specify several important ways of extending the resulting migration model and improving its empirical performance." The analysis is based on Italian data. excerpt

  18. Trace element evaluation of different varieties of chewing gum by radiochemical neutron activation analysis

    International Nuclear Information System (INIS)

    Zaidi, J.H.; Arif, M.; Fatima, I.; Ahmad, S.; Qureshi, I.H.

    2000-01-01

    Extensive use of chewing gums, by children in particular, entails the evaluation of trace element contents in them. Radiochemical neutron activation analysis (RNAA) was successfully employed to determine the concentration of 35 trace elements (essential, toxic and nonessential) in eight different brands of chewing gum generally consumed in Rawalpindi/Islamabad area. Comparison of trace element data of our work with literature has been presented. None of the elements detected in the brands of chewing gum examined was found to be present at a level representing a substantial contribution to the total dietary intake of the element. (author)

  19. Quantitative and qualitative approaches to identifying migration chronology in a continental migrant.

    Directory of Open Access Journals (Sweden)

    William S Beatty

    Full Text Available The degree to which extrinsic factors influence migration chronology in North American waterfowl has not been quantified, particularly for dabbling ducks. Previous studies have examined waterfowl migration using various methods, however, quantitative approaches to define avian migration chronology over broad spatio-temporal scales are limited, and the implications for using different approaches have not been assessed. We used movement data from 19 female adult mallards (Anas platyrhynchos equipped with solar-powered global positioning system satellite transmitters to evaluate two individual level approaches for quantifying migration chronology. The first approach defined migration based on individual movements among geopolitical boundaries (state, provincial, international, whereas the second method modeled net displacement as a function of time using nonlinear models. Differences in migration chronologies identified by each of the approaches were examined with analysis of variance. The geopolitical method identified mean autumn migration midpoints at 15 November 2010 and 13 November 2011, whereas the net displacement method identified midpoints at 15 November 2010 and 14 November 2011. The mean midpoints for spring migration were 3 April 2011 and 20 March 2012 using the geopolitical method and 31 March 2011 and 22 March 2012 using the net displacement method. The duration, initiation date, midpoint, and termination date for both autumn and spring migration did not differ between the two individual level approaches. Although we did not detect differences in migration parameters between the different approaches, the net displacement metric offers broad potential to address questions in movement ecology for migrating species. Ultimately, an objective definition of migration chronology will allow researchers to obtain a comprehensive understanding of the extrinsic factors that drive migration at the individual and population levels. As a result

  20. Quantitative and qualitative approaches to identifying migration chronology in a continental migrant

    Science.gov (United States)

    Beatty, William S.; Kesler, Dylan C.; Webb, Elisabeth B.; Raedeke, Andrew H.; Naylor, Luke W.; Humburg, Dale D.

    2013-01-01

    The degree to which extrinsic factors influence migration chronology in North American waterfowl has not been quantified, particularly for dabbling ducks. Previous studies have examined waterfowl migration using various methods, however, quantitative approaches to define avian migration chronology over broad spatio-temporal scales are limited, and the implications for using different approaches have not been assessed. We used movement data from 19 female adult mallards (Anas platyrhynchos) equipped with solar-powered global positioning system satellite transmitters to evaluate two individual level approaches for quantifying migration chronology. The first approach defined migration based on individual movements among geopolitical boundaries (state, provincial, international), whereas the second method modeled net displacement as a function of time using nonlinear models. Differences in migration chronologies identified by each of the approaches were examined with analysis of variance. The geopolitical method identified mean autumn migration midpoints at 15 November 2010 and 13 November 2011, whereas the net displacement method identified midpoints at 15 November 2010 and 14 November 2011. The mean midpoints for spring migration were 3 April 2011 and 20 March 2012 using the geopolitical method and 31 March 2011 and 22 March 2012 using the net displacement method. The duration, initiation date, midpoint, and termination date for both autumn and spring migration did not differ between the two individual level approaches. Although we did not detect differences in migration parameters between the different approaches, the net displacement metric offers broad potential to address questions in movement ecology for migrating species. Ultimately, an objective definition of migration chronology will allow researchers to obtain a comprehensive understanding of the extrinsic factors that drive migration at the individual and population levels. As a result, targeted

  1. Evaluation of the finite element software ABAQUS for biomechanical modelling of biphasic tissues.

    Science.gov (United States)

    Wu, J Z; Herzog, W; Epstein, M

    1998-02-01

    The biphasic cartilage model proposed by Mow et al. (1980) has proven successful to capture the essential mechanical features of articular cartilage. In order to analyse the joint contact mechanics in real, anatomical joints, the cartilage model needs to be implemented into a suitable finite element code to approximate the irregular surface geometries of such joints. However, systematic and extensive evaluation of the capacity of commercial software for modelling the contact mechanics with biphasic cartilage layers has not been made. This research was aimed at evaluating the commercial finite element software ABAQUS for analysing biphasic soft tissues. The solutions obtained using ABAQUS were compared with those obtained using other finite element models and analytical solutions for three numerical tests: an unconfined indentation test, a test with the contact of a spherical cartilage surface with a rigid plate, and an axi-symmetric joint contact test. It was concluded that the biphasic cartilage model can be implemented into the commercial finite element software ABAQUS to analyse practical joint contact problems with biphasic articular cartilage layers.

  2. [The migration crisis of the summer of 1994. Balance and perspectives of Cuban emigration flows: 1984-1996].

    Science.gov (United States)

    Rodriguez Chavez, E

    1996-01-01

    "The article argues that the rafters crisis of 1994 and the resulting migration agreements between the United States and Cuba in 1994 and 1995 were a radical turn in policies and migration flows between the two countries. The article also describes the general evolution of Cuban migration flows towards the U.S. from the 1984 bilateral agreement up to 1996. As a context, it describes the structural elements of recent Cuban emigration and the place Cubans occupy in the general immigration from Latin America and the Caribbean." (EXCERPT)

  3. 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

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

    Directory of Open Access Journals (Sweden)

    Brian BARNARD

    2017-09-01

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

  5. 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.

  6. The possibilities of compressed-sensing-based Kirchhoff prestack migration

    KAUST Repository

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

    2014-01-01

    An approximate subsurface reflectivity distribution of the earth is usually obtained through the migration process. However, conventional migration algorithms, including those based on the least-squares approach, yield structure descriptions that are slightly smeared and of low resolution caused by the common migration artifacts due to limited aperture, coarse sampling, band-limited source, and low subsurface illumination. To alleviate this problem, we use the fact that minimizing the L1-norm of a signal promotes its sparsity. Thus, we formulated the Kirchhoff migration problem as a compressed-sensing (CS) basis pursuit denoise problem to solve for highly focused migrated images compared with those obtained by standard and least-squares migration algorithms. The results of various subsurface reflectivity models revealed that solutions computed using the CS based migration provide a more accurate subsurface reflectivity location and amplitude. We applied the CS algorithm to image synthetic data from a fault model using dense and sparse acquisition geometries. Our results suggest that the proposed approach may still provide highly resolved images with a relatively small number of measurements. We also evaluated the robustness of the basis pursuit denoise algorithm in the presence of Gaussian random observational noise and in the case of imaging the recorded data with inaccurate migration velocities.

  7. The possibilities of compressed-sensing-based Kirchhoff prestack migration

    KAUST Repository

    Aldawood, Ali

    2014-05-08

    An approximate subsurface reflectivity distribution of the earth is usually obtained through the migration process. However, conventional migration algorithms, including those based on the least-squares approach, yield structure descriptions that are slightly smeared and of low resolution caused by the common migration artifacts due to limited aperture, coarse sampling, band-limited source, and low subsurface illumination. To alleviate this problem, we use the fact that minimizing the L1-norm of a signal promotes its sparsity. Thus, we formulated the Kirchhoff migration problem as a compressed-sensing (CS) basis pursuit denoise problem to solve for highly focused migrated images compared with those obtained by standard and least-squares migration algorithms. The results of various subsurface reflectivity models revealed that solutions computed using the CS based migration provide a more accurate subsurface reflectivity location and amplitude. We applied the CS algorithm to image synthetic data from a fault model using dense and sparse acquisition geometries. Our results suggest that the proposed approach may still provide highly resolved images with a relatively small number of measurements. We also evaluated the robustness of the basis pursuit denoise algorithm in the presence of Gaussian random observational noise and in the case of imaging the recorded data with inaccurate migration velocities.

  8. Influence of data irregularities on 3-D common offset migration; Influence d'irregularites dans l'echantillonnage des donnees sur la migration 3D par deport

    Energy Technology Data Exchange (ETDEWEB)

    Assouline, F.; Lailly, P. [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France); Assouline, F [Pau Univ., 64 (France)

    2001-07-01

    In 3-D seismic survey, offset is a vector characterized by the source-receiver distance and azimuth. Due to irregularities in the acquisition (for instance streamer feathering in marine acquisition) common offset data are not available and, in turn, 3-D common offset migration does not make sense any longer. We then introduce the concept of migration by offset class: it is a straightforward extension of common offset migration in which we migrate all traces that belong to a given offset class, namely all traces with offset close to a given one. The result of such a migration depends of course on how the offset class is constructed or, in other words, on what is meant with 'close '. The aim of this paper is to investigate by means of a 3-D numerical study how to design offset classes so as to obtain migrated images that can be interpreted without trouble (such an interpretation is a key element for a successful migration velocity analysis). We have to find a trade-off between two extremes: - a too loose offset class that would mix heterogeneous offsets (in particular mixing substantially different azimuths can be dangerous); - a too narrow offset class that would result in sparse seismic traces with, in turn, an inadequate coverage of the reflector. The regularity, within an offset class, of the offset variation as well as the one of the distribution of midpoints are parameters that can have a drastic influence on the quality of the migrated image. It is shown that migration by offset class appears as a robust procedure all the more than the offset varies slowly with the midpoint coordinate within an offset class. Besides, the smaller the mean offset norm, the lower is the contamination of the image due to the mixing of azimuths within an offset class. (authors)

  9. Evaluation of radionuclide migration in the homogeneous system of a geological repository

    International Nuclear Information System (INIS)

    Prvakova, S.; Duran, J.; Necas, V.

    2005-01-01

    The aim of this paper is to study radionuclide migration and release from a deep underground repository situated in a clay formation. An insight into the processes influencing the radionuclide transport in the near field and far field will be presented. For the calculation, a set of radionuclides has been chosen, considering the half-life, decay chains, capacity of the sorption, solubility limits and diffusion coefficients. The migration of radionuclides is dependent on transport properties of the particular nuclide. Due to the low hydraulic conductivity of the backfill material and clay geological formation, the transport in the repository occurs mainly by diffusion. The migration rate will be influenced by the water chemistry, solubility, retardation and diffusive properties of the nuclides, and the water flow rate in the clay. The release rates of radionuclides from the geosphere to the biosphere will be converted into the indicative dose rates using dose conversion factors for ingestion. The impact of the critical group is considered via consumption of meat, root vegetables and drinking water from wells. (author)

  10. Final Report: Migration Mechanisms for Large-scale Parallel Applications

    Energy Technology Data Exchange (ETDEWEB)

    Jason Nieh

    2009-10-30

    Process migration is the ability to transfer a process from one machine to another. It is a useful facility in distributed computing environments, especially as computing devices become more pervasive and Internet access becomes more ubiquitous. The potential benefits of process migration, among others, are fault resilience by migrating processes off of faulty hosts, data access locality by migrating processes closer to the data, better system response time by migrating processes closer to users, dynamic load balancing by migrating processes to less loaded hosts, and improved service availability and administration by migrating processes before host maintenance so that applications can continue to run with minimal downtime. Although process migration provides substantial potential benefits and many approaches have been considered, achieving transparent process migration functionality has been difficult in practice. To address this problem, our work has designed, implemented, and evaluated new and powerful transparent process checkpoint-restart and migration mechanisms for desktop, server, and parallel applications that operate across heterogeneous cluster and mobile computing environments. A key aspect of this work has been to introduce lightweight operating system virtualization to provide processes with private, virtual namespaces that decouple and isolate processes from dependencies on the host operating system instance. This decoupling enables processes to be transparently checkpointed and migrated without modifying, recompiling, or relinking applications or the operating system. Building on this lightweight operating system virtualization approach, we have developed novel technologies that enable (1) coordinated, consistent checkpoint-restart and migration of multiple processes, (2) fast checkpointing of process and file system state to enable restart of multiple parallel execution environments and time travel, (3) process migration across heterogeneous

  11. Automated element identification for EDS spectra evaluation using quantification and integrated spectra simulation approaches

    International Nuclear Information System (INIS)

    Eggert, F

    2010-01-01

    This work describes first real automated solution for qualitative evaluation of EDS spectra in X-ray microanalysis. It uses a combination of integrated standardless quantitative evaluation, computation of analytical errors to a final uncertainty, and parts of recently developed simulation approaches. Multiple spectra reconstruction assessments and peak searches of the residual spectrum are powerful enough to solve the qualitative analytical question automatically for totally unknown specimens. The integrated quantitative assessment is useful to improve the confidence of the qualitative analysis. Therefore, the qualitative element analysis becomes a part of integrated quantitative spectrum evaluation, where the quantitative results are used to iteratively refine element decisions, spectrum deconvolution, and simulation steps.

  12. 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 ...

  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. Crosstalk between intracellular and extracellular signals regulating interneuron production, migration and integration into the cortex.

    Science.gov (United States)

    Peyre, Elise; Silva, Carla G; Nguyen, Laurent

    2015-01-01

    During embryogenesis, cortical interneurons are generated by ventral progenitors located in the ganglionic eminences of the telencephalon. They travel along multiple tangential paths to populate the cortical wall. As they reach this structure they undergo intracortical dispersion to settle in their final destination. At the cellular level, migrating interneurons are highly polarized cells that extend and retract processes using dynamic remodeling of microtubule and actin cytoskeleton. Different levels of molecular regulation contribute to interneuron migration. These include: (1) Extrinsic guidance cues distributed along migratory streams that are sensed and integrated by migrating interneurons; (2) Intrinsic genetic programs driven by specific transcription factors that grant specification and set the timing of migration for different subtypes of interneurons; (3) Adhesion molecules and cytoskeletal elements/regulators that transduce molecular signalings into coherent movement. These levels of molecular regulation must be properly integrated by interneurons to allow their migration in the cortex. The aim of this review is to summarize our current knowledge of the interplay between microenvironmental signals and cell autonomous programs that drive cortical interneuron porduction, tangential migration, and intergration in the developing cerebral cortex.

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

    Science.gov (United States)

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

    2014-06-01

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

  16. Quantitative methods for analysing cumulative effects on fish migration success: a review.

    Science.gov (United States)

    Johnson, J E; Patterson, D A; Martins, E G; Cooke, S J; Hinch, S G

    2012-07-01

    It is often recognized, but seldom addressed, that a quantitative assessment of the cumulative effects, both additive and non-additive, of multiple stressors on fish survival would provide a more realistic representation of the factors that influence fish migration. This review presents a compilation of analytical methods applied to a well-studied fish migration, a more general review of quantitative multivariable methods, and a synthesis on how to apply new analytical techniques in fish migration studies. A compilation of adult migration papers from Fraser River sockeye salmon Oncorhynchus nerka revealed a limited number of multivariable methods being applied and the sub-optimal reliance on univariable methods for multivariable problems. The literature review of fisheries science, general biology and medicine identified a large number of alternative methods for dealing with cumulative effects, with a limited number of techniques being used in fish migration studies. An evaluation of the different methods revealed that certain classes of multivariable analyses will probably prove useful in future assessments of cumulative effects on fish migration. This overview and evaluation of quantitative methods gathered from the disparate fields should serve as a primer for anyone seeking to quantify cumulative effects on fish migration survival. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  17. 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...

  18. Energy Sustainability Evaluation Model Based on the Matter-Element Extension Method: A Case Study of Shandong Province, China

    Directory of Open Access Journals (Sweden)

    Siqi Li

    2017-11-01

    Full Text Available Energy sustainability is of vital importance to regional sustainability, because energy sustainability is closely related to both regional economic growth and social stability. The existing energy sustainability evaluation methods lack a unified system to determine the relevant influencing factors, are relatively weak in quantitative analysis, and do not fully describe the ‘paradoxical’ characteristics of energy sustainability. To solve those problems and to reasonably and objectively evaluate energy sustainability, we propose an energy sustainability evaluation model based on the matter-element extension method. We first select energy sustainability evaluation indexes based on previous research and experience. Then, a variation coefficient method is used to determine the weights of these indexes. Finally, the study establishes the classical domain, joint domain, and the matter-element relationship to evaluate energy sustainability through matter-element extension. Data from Shandong Province is used as a case study to evaluate the region’s energy sustainability. The case study shows that the proposed energy sustainability evaluation model, based on the matter-element extension method, can effectively evaluate regional energy sustainability.

  19. Application of centrifuge modelling and radiotracers to migration studies of buried toxic waste

    International Nuclear Information System (INIS)

    Villar, H.P.

    1995-01-01

    A new technique to study the migration of souble waste components in soils, based on the application of centrifugue modelling and of selected short-lived radiotracers, is presented. The technique is based on the acceleration of the migration proceses of a specific tracer in a soil model, with simple and well-established scaling laws being used to interpret the results. The use of radiotracers allows geat flexibility and the adoption of a wide range of concentrations. Demosntrations of the technique have been carried out with two elements of radically distinct behaviour: iodine noted for its mobility in soils, and thallium, which tends to be strongly sorbed. Two different soil types have been used. The results semed to confirm what is known about the behaviour of both elements, so that the feasibility of the technique for such studies has been concluded. (author). 7 refs, 4 figs, 1 tab

  20. The Trends in International Migration of Human Resources under Conditions of Geo-Economic Transformations

    Directory of Open Access Journals (Sweden)

    Shymanska Kateryna V.

    2017-06-01

    Full Text Available The aim of the article is to reveal the influence of geo-economic transformations on the trends in international migration of human resources as an element of the resource potential of countries and regions. The current state of geo-economic transformations is analyzed, and their influence on the processes of international migration of human resources is revealed. The relevance of analyzing international movement of human resources, not labor ones, in building the geo-economic strategy of a country or a regional grouping is justified. The connection between the international migration of human resources and the trends in development of individual countries and regions (oil exporting countries, newly industrialized countries and least developed agrarian countries is determined, the general patterns of migration flows in these countries are described. Furthermore, the topical issues in studying international migration of human resources in the context of the directions of geo-economics identified by scientists are formulated. It is determined that the regional migration policy should contribute to maximizing the benefits of migration of human resources for the development of the region and the use of immigrants in the countries of the region as an economic resource that becomes strategically important under conditions of geo-economic transformations.

  1. The Social Determinants of Refugee Mental Health in the Post-Migration Context: A Critical Review.

    Science.gov (United States)

    Hynie, Michaela

    2018-05-01

    With the global increase in the number of refugees and asylum seekers, mental health professionals have become more aware of the need to understand and respond to the mental health needs of forced migrants. This critical review summarizes the findings of recent systematic reviews and primary research on the impact of post-migration conditions on mental disorders and PTSD among refugees and asylum seekers. Historically, the focus of mental health research and interventions with these populations has been on the impact of pre-migration trauma. Pre-migration trauma does predict mental disorders and PTSD, but the post-migration context can be an equally powerful determinant of mental health. Moreover, post-migration factors may moderate the ability of refugees to recover from pre-migration trauma. The importance of post-migration stressors to refugee mental health suggests the need for therapeutic interventions with psychosocial elements that address the broader conditions of refugee and asylum seekers' lives. However, there are few studies of multimodal interventions with refugees, and even fewer with control conditions that allow for conclusions about their effectiveness. These findings are interpreted using a social determinants of health framework that connects the risk and protective factors in the material and social conditions of refugees' post-migration lives to broader social, economic and political factors.

  2. 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)

  3. Design evaluation of the HTGR fuel element size reduction system

    International Nuclear Information System (INIS)

    Strand, J.B.

    1978-06-01

    A fuel element size reduction system for the ''cold'' pilot plant of the General Atomic HTGR Reference Recycle Facility has been designed and tested. This report is both an evaluation of the design based on results of initial tests and a description of those designs which require completion or modification for hot cell use. 11 figures

  4. Uncertainty evaluation in correlated quantities: application to elemental analysis of atmospheric aerosols

    International Nuclear Information System (INIS)

    Espinosa, A.; Miranda, J.; Pineda, J. C.

    2010-01-01

    One of the aspects that are frequently overlooked in the evaluation of uncertainty in experimental data is the possibility that the involved quantities are correlated among them, due to different causes. An example in the elemental analysis of atmospheric aerosols using techniques like X-ray Fluorescence (X RF) or Particle Induced X-ray Emission (PIXE). In these cases, the measured elemental concentrations are highly correlated, and then are used to obtain information about other variables, such as the contribution from emitting sources related to soil, sulfate, non-soil potassium or organic matter. This work describes, as an example, the method required to evaluate the uncertainty in variables determined from correlated quantities from a set of atmospheric aerosol samples collected in the Metropolitan Area of the Mexico Valley and analyzed with PIXE. The work is based on the recommendations of the Guide for the Evaluation of Uncertainty published by the International Organization for Standardization. (Author)

  5. The CT and MR evaluation of migrational disorders of the brain. Pt. 2

    International Nuclear Information System (INIS)

    Byrd, S.E.; Osborn, R.E.; Bohan, T.P.; Naidich, T.P.

    1989-01-01

    The migrational disorders are a rare group of congenital malformations of the brain. They consist of the following entities - lissencephaly (agyria - pachygyria), pachygyria, schizencephaly, heterotopia and polymicrogyria. We studied 40 children with migrational disorders radiologically with CT and MR. This article (Part II) deals with our patients with schizencephaly, heterotopia and polymicrogyria. These patients presented clinically with a variety of symptoms. The most common were seizures, delayed development, failure to thrive and hydrocephalus. CT and MR both demonstrated the characteristic findings in all of our patients except the polymicrogyria group. The gray matter and cleft abnormalities seen in these disorders were demonstrated with CT and MR. However, MR provided better delineation of these disorders than CT. Because some forms of migrational disorders can be inherited, it is extremely important for the radiologist to understand the characteristic findings for correct diagnosis which is essential for parental counseling. (orig.)

  6. Migration study of actinides and lanthanides in compacted bentonite

    International Nuclear Information System (INIS)

    Sastrowardoyo, P.B.; Susilowati, D.; Suganda, D.

    1998-01-01

    Migration study of actinide and lanthanide elements in compacted bentonite has been conducted. Data of these elements mobilities have been shown, and it is showed that the diffusion coefficient was varied as the function of solution phase condition as well as the origin/composition of bentonite. It is showed that the diffusion coefficient decreased by the increasing of density, as well as the increasing of montmorillonite content in bentonite. The ratio of bentonite/silica-sand used was related to the increasing of elements mobility. In many case the difference of diffusion coefficient was related to the variation of pH and redox condition, as well as the presence of complexant in solution phase. The Lower diffusion coefficient could give the higher retardation factor, which is a favourable factor to retard the radionuclides release from a disposal facility to geosphere. (author)

  7. Database on gas migration tests through bentonite buffer material

    International Nuclear Information System (INIS)

    Tanai, Kenji

    2009-02-01

    Carbon steel is a candidate material for an overpack for geological disposal of high-level radioactive waste in Japan. The corrosion of the carbon steel overpack in aqueous solution under anoxic conditions will cause the generation of hydrogen gas, which may affect hydrological and mechanical properties of the bentonite buffer. To evaluate such an effect of gas generation, it is necessary to develop a model of gas migration through bentonite buffer material taking account of data obtained from experiments. The gas migration experiments under both unsaturated and saturated conditions have been carried out to clarify the fundamental characteristics of bentonite for gas migration. This report compiles the experimental data obtained from gas migration tests for buffer material which has been conducted by JAEA until December, 2007. A CD-ROM is attached as an appendix. (author)

  8. Radon depth migration

    International Nuclear Information System (INIS)

    Hildebrand, S.T.; Carroll, R.J.

    1993-01-01

    A depth migration method is presented that used Radon-transformed common-source seismograms as input. It is shown that the Radon depth migration method can be extended to spatially varying velocity depth models by using asymptotic ray theory (ART) to construct wavefield continuation operators. These operators downward continue an incident receiver-array plane wave and an assumed point-source wavefield into the subsurface. The migration velocity model is constrain to have longer characteristic wavelengths than the dominant source wavelength such that the ART approximations for the continuation operators are valid. This method is used successfully to migrate two synthetic data examples: (1) a point diffractor, and (2) a dipping layer and syncline interface model. It is shown that the Radon migration method has a computational advantage over the standard Kirchhoff migration method in that fewer rays are computed in a main memory implementation

  9. Radionuclide migration test using undisturbed aerated soil

    International Nuclear Information System (INIS)

    Yamamoto, Tadatoshi; Ohtsuka, Yoshiro; Ogawa, Hiromichi; Wadachi, Yoshiki

    1988-01-01

    As one of the most important part of safety assessment on the shallow land disposal of lowlevel radioactive waste, the radionuclide migration was studied using undisturbed soil samples, in order to evaluate an exact radionuclide migration in an aerated soil layer. Soil samples used in the migration test were coastal sand and loamy soil which form typical surface soil layers in Japan. The aqueous solution containing 60 CoCl 2 , 85 SrCl 2 and 137 CsCl was fed into the soil column and concentration of each radionuclide both in effluent and in soil was measured. Large amount of radionuclides was adsorbed on the surface of soil column and small amount of radionuclides moved deep into the soil column. Difference in the radionuclide profile was observed in the low concentration portion particularly. It is that some fractions of 60 Co and 137 Cs are stable in non-ionic form and move downward through the soil column together with water. The radionuclide distribution in the surface of soil column can be fairly predicted with a conventional migration equation for ionic radionuclides. As a result of radionuclide adsorption, both aerated soil layers of coastal sand and loamy soil have large barrier ability on the radionuclide migration through the ground. (author)

  10. Evaluation of anti-migration properties of biliary covered self-expandable metal stents.

    Science.gov (United States)

    Minaga, Kosuke; Kitano, Masayuki; Imai, Hajime; Harwani, Yogesh; Yamao, Kentaro; Kamata, Ken; Miyata, Takeshi; Omoto, Shunsuke; Kadosaka, Kumpei; Sakurai, Toshiharu; Nishida, Naoshi; Kudo, Masatoshi

    2016-08-14

    To assess anti-migration potential of six biliary covered self-expandable metal stents (C-SEMSs) by using a newly designed phantom model. In the phantom model, the stent was placed in differently sized holes in a silicone wall and retracted with a retraction robot. Resistance force to migration (RFM) was measured by a force gauge on the stent end. Radial force (RF) was measured with a RF measurement machine. Measured flare structure variables were the outer diameter, height, and taper angle of the flare (ODF, HF, and TAF, respectively). Correlations between RFM and RF or flare variables were analyzed using a linear correlated model. Out of the six stents, five stents were braided, the other was laser-cut. The RF and RFM of each stent were expressed as the average of five replicate measurements. For all six stents, RFM and RF decreased as the hole diameter increased. For all six stents, RFM and RF correlated strongly when the stent had not fully expanded. This correlation was not observed in the five braided stents excluding the laser cut stent. For all six stents, there was a strong correlation between RFM and TAF when the stent fully expanded. For the five braided stents, RFM after full stent expansion correlated strongly with all three stent flare structure variables (ODF, HF, and TAF). The laser-cut C-SEMS had higher RFMs than the braided C-SEMSs regardless of expansion state. RF was an important anti-migration property when the C-SEMS did not fully expand. Once fully expanded, stent flare structure variables plays an important role in anti-migration.

  11. A critical survey of live virtual machine migration techniques

    Directory of Open Access Journals (Sweden)

    Anita Choudhary

    2017-11-01

    Full Text Available Abstract Virtualization techniques effectively handle the growing demand for computing, storage, and communication resources in large-scale Cloud Data Centers (CDC. It helps to achieve different resource management objectives like load balancing, online system maintenance, proactive fault tolerance, power management, and resource sharing through Virtual Machine (VM migration. VM migration is a resource-intensive procedure as VM’s continuously demand appropriate CPU cycles, cache memory, memory capacity, and communication bandwidth. Therefore, this process degrades the performance of running applications and adversely affects efficiency of the data centers, particularly when Service Level Agreements (SLA and critical business objectives are to be met. Live VM migration is frequently used because it allows the availability of application service, while migration is performed. In this paper, we make an exhaustive survey of the literature on live VM migration and analyze the various proposed mechanisms. We first classify the types of Live VM migration (single, multiple and hybrid. Next, we categorize VM migration techniques based on duplication mechanisms (replication, de-duplication, redundancy, and compression and awareness of context (dependency, soft page, dirty page, and page fault and evaluate the various Live VM migration techniques. We discuss various performance metrics like application service downtime, total migration time and amount of data transferred. CPU, memory and storage data is transferred during the process of VM migration and we identify the category of data that needs to be transferred in each case. We present a brief discussion on security threats in live VM migration and categories them in three different classes (control plane, data plane, and migration module. We also explain the security requirements and existing solutions to mitigate possible attacks. Specific gaps are identified and the research challenges in improving

  12. Study on the dynamics of halogen elements in the agro-environment and these element`s deficiency, toxicity and environmental hazards by the application of the neutron activation analysis method

    Energy Technology Data Exchange (ETDEWEB)

    Yuita, Kouichi [National Inst. of Agro-Environmental Sciences, Tsukuba, Ibaraki (Japan)

    1998-03-01

    A neutron activation analysis method is an accurate and highly sensitive method for analyzing halogen elements (iodine, bromine and chlorine) except fluorine. It is unsubstitutable and valuable method especially for iodine (including radioactive {sup 129}I) and bromine which are present at lower levels. Halogen elements have high chemical and physiological activities and move widely in the environment. As a result, deficiency and an excess of halogen elements in plants and animals have occurred and artificial halogen compounds have caused environmental pollution in wide areas. We efficiently utilized the neutron activation analysis method and an activable tracer method to obtain valuable findings which contribute to the clarification of and measures against these actual problems and which are also concerned with the occurrence, distribution and migration of halogen elements in the environment, especially agricultural and forestry ecosystems in space and in time. (author)

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

    Directory of Open Access Journals (Sweden)

    Shymanska K.V.

    2017-03-01

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

  14. Work ability of Chinese migrant workers: the influence of migration characteristics

    OpenAIRE

    Han, Lu; Shi, Leiyu; Lu, Liming; Ling, Li

    2014-01-01

    Background Migrant workers have become a vital labor supply to China’s economy. Their migration process and work conditions may influence their health and work ability. The work ability of migrant workers in China and the influence of the migration process on work ability have not been explored extensively in previous studies. The objective of this study is to evaluate the association of migration characteristics and work-related factors with work ability among migrant workers in the Pearl Ri...

  15. Amplitude calculations for 3D Gaussian beam migration using complex-valued traveltimes

    International Nuclear Information System (INIS)

    Bleistein, Norman; Gray, Samuel H

    2010-01-01

    Gaussian beams are often used to represent Green's functions in three-dimensional Kirchhoff-type true-amplitude migrations because such migrations made using Gaussian beams yield superior images to similar migrations using classical ray-theoretic Green's functions. Typically, the integrand of a migration formula consists of two Green's functions—each describing propagation to the image point—one from the source and the other from the receiver position. The use of Gaussian beams to represent each of these Green's functions in 3D introduces two additional double integrals when compared to a Kirchhoff migration using ray-theoretic Green's functions, thereby adding a significant computational burden. Hill (2001 Geophysics 66 1240–50) proposed a method for reducing those four integrals to two, compromising slightly on the full potential quality of the Gaussian beam representations for the sake of more efficient computation. That approach requires a two-dimensional steepest descent analysis for the asymptotic evaluation of a double integral. The method requires evaluation of the complex traveltimes of the Gaussian beams as well as the amplitudes of the integrands at the determined saddle points. In addition, it is necessary to evaluate the determinant of a certain (Hessian) matrix of second derivatives. Hill (2001 Geophysics 66 1240–50) did not report on this last part; thus, his proposed migration formula is kinematically correct but lacks correct amplitude behavior. In this paper, we derive a formula for that Hessian matrix in terms of dynamic ray tracing quantities. We also show in a simple example how the integral that we analyze here arises in a true amplitude migration formula

  16. Evaluation of trace elements in some northern-Nigeria traditional medicinal plants using INAA technique

    International Nuclear Information System (INIS)

    Oladipo, M.O.A.; Njinga, R.L.; Baba, A.; Muhammad, H.L.

    2012-01-01

    Instrumental neutron activation analysis was used for multi-trace elemental determination of six medicinal plants: Boerhavia diffusa, Euphoria hirta, Senna occidentalis, Senna obtusofolia, Cyprus dilatatus and Mitracarpus villosu. These plants were irradiated in the Nigeria Research reactor-1, at flux levels of 2.25E+11 ncm −2 s −1 in the outer channel and 5.0E+11 ncm −2 s −1 in the inner channel. A total of the twenty one elemental concentrations were evaluated highlighted the similarity between the elements obtained for the six plants. It was found that Euphoria hirta and Senna occidentalis have similar concentrations of elements. Boerhavia difusa, Mitracarpus villosus, Cyprus dilatalus and Senna obttusifolia were also similar in elemental content to each other, while Boerhavia difusa was the only exceptional outlier. The accuracy of measurements was evaluated by analyzing IAEA-359 cabbage references standard materials and the results show good agreement with certified or literature values within ±0.01% to ±0.87%. - Highlights: ► Application of neutron activation analysis. ► Multi-trace elemental determination of six medicinal plants in northern Nigeria. ► Accuracy of the measurements was based on analyzing IAEA-359 cabbage, a standard reference material. ► Results showed good agreement with certified values within ±0.01 % to ±0.87%.

  17. Civil migration and risk assessment methodology

    International Nuclear Information System (INIS)

    Onishi, Y.; Brown, S.M.; Olsen, A.R.; Parkhurst, M.A.

    1981-01-01

    To provide a scientific basis for risk assessment and decision making, the Chemical Migration and Risk Assessment (CMRA) Methodology was developed to simulate overland and instream toxic containment migration and fate, and to predict the probability of acute and chronic impacts on aquatic biota. The simulation results indicated that the time between the pesticide application and the subsequent runoff producing event was the most important factor determining the amount of the alachlor. The study also revealed that sediment transport has important effects on contaminant migration when sediment concentrations in receiving streams are high or contaminants are highly susceptible to adsorption by sediment. Although the capabilities of the CMRA methodology were only partially tested in this study, the results demonstrate that methodology can be used as a scientific decision-making tool for toxic chemical regulations, a research tool to evaluate the relative significance of various transport and degradation phenomena, as well as a tool to examine the effectiveness of toxic chemical control practice

  18. MR imaging of neuronal migration anomaly

    International Nuclear Information System (INIS)

    Hong, Hyun Sook; Choi, Eun Wan; Kim, Dae Ho; Chung, Moo Chan; Kwon, Kuy Hyang; Kim, Ki Jung

    1991-01-01

    Abnormalities of neuronal migration are characterized by anectopic location of neurons in the cerebral cortex. This broad group of anomalies includes agyria, pachygyria, schizencephaly, unilateral megalencephaly, and gray matter heterotopia. Patients with this anomaly present clinically with a variety of symptoms which are proportional to the extent of the brain involved. These abnormalities have characterized pathologically in vivo by sonography and CT scan. MR appears to be an imaging technique of choice in evaluating these anomalies because it is capable of exceptionally good differentiation between gray and white matter, high contrast resolution, multiplanar display of the anatomy, and lack of overlying bone artifac. The purpose of this paper is to describe the MR findings of neuronal migration anomaly. The results of our study support that MR appears to be the imaging method of choice for diagnosing migration anomalies and the primary screening method for infants or children who have seisure/and delayed development

  19. [Evaluation of formal elements of Spanish pediatrics journals].

    Science.gov (United States)

    Aleixandre-Benavent, R; González de Dios, J; Valderrama-Zurián, F J; Bolaños Pizarro, M; Valderrama-Zurián, J C

    2007-03-01

    Standardization of scientific journals is indispensable for accurate transmission of knowledge, since it guarantees the universality and reproducibility of research. The objective of this study was to evaluate the formal elements of Spanish pediatrics journals. In 2005, we studied the characteristics of Spanish biomedical journals with special emphasis on Spanish pediatrics journals. The form used for the selection of journals for inclusion in the database Indice Médico Español (IME) was employed to evaluate 65 distinct characteristics in each journal. The parameters were grouped in the following five categores: journal presentation, presentation of the articles, scientific and editorial committees, content characteristics, and dissemination parameters. The journals with the highest overall scores were Anales de Pediatría (63 points out of a maximum of 82), followed by Pediatría de Atención Primaria (53 points), Acta Pediátrica Española and Cirugía Pediátrica (55 points each), Pediatrika (53 points), and Revista Española de Pediatría (48 points). The score obtained by Anales de Pediatría places this journal in the top 10 Spanish journals included in IME. Spanish pediatrics journals meet most of the formal elements required of biomedical journals, although some aspects could be improved, such as deficiencies in the frequency and regularity of publication, mention of the dates of manuscript receipt and acceptance, the lack of a clear description of the editorial process of manuscript selection and peer review, the absence of committee members' institutional affiliations, and the absence of articles by non-Spanish authors.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  1. CT and MR evaluation of migrational disorders of the brain. Pt. 1. Lissencephaly and pachygyria

    Energy Technology Data Exchange (ETDEWEB)

    Byrd, S E; Osborn, R E; Bohan, T P; Naidich, T P

    1989-03-01

    The migrational disorders are a rare group of congenital malformations of the brain. They consist of the following entities - lissencephaly (agyria-pachygyria), pachygyria, schizencephaly, heterotopia and polymicrogyria. We studied 40 children with migrational disorders radiologically with CT and MR. This article (part I) deals with our patients with lissencephaly and pachygyria. It emphasizes their characteristic CT and MR findings along with their clinical presentation and course. These patients presented with one or a combination of the following symptoms, hypotonia, seizures, failure to thrive, microcephaly and occasionally hydrocephalus. These two groups of migrational disorders have abnormalities affecting the gyral-sulcal pattern of the cortex and gray-white matter distribution of the brain. MR provided better delineation of these disorders than CT. Because some forms of the migrational disorders can be inherited, it is extremely important for the radiologist to understand the characteristic findings for correct diagnosis which is essential for parental counseling.

  2. Macrophage migration inhibitory factor as an incriminating agent in vitiligo.

    Science.gov (United States)

    Farag, Azza Gaber Antar; Hammam, Mostafa Ahmed; Habib, Mona SalahEldeen; Elnaidany, Nada Farag; Kamh, Mona Eaid

    2018-03-01

    Vitiligo is an autoimmune skin disorder in which the loss of melanocytes is mainly attributed to defective autoimmune mechanisms and, lately, there has been more emphasis on autoinflammatory mediators. Among these is the macrophage migration inhibitory factor, which is involved in many autoimmune skin diseases. However, little is known about the contribution of this factor to vitiligo vulgaris. To determine the hypothesized role of migration inhibitory factor in vitiligo via estimation of serum migration inhibitory factor levels and migration inhibitory factor mRNA concentrations in patients with vitiligo compared with healthy controls. We also aimed to assess whether there is a relationship between the values of serum migration inhibitory factor and/or migration inhibitory factor mRNA with disease duration, clinical type and severity in vitiligo patients. Evaluation of migration inhibitory factor serum level and migration inhibitory factor mRNA expression by ELISA and real-time PCR, respectively, were performed for 50 patients with different degrees of vitiligo severity and compared to 15 age- and gender-matched healthy volunteers as controls. There was a highly significant increase in serum migration inhibitory factor and migration inhibitory factor mRNA levels in vitiligo cases when compared to controls (pvitiligo patients, and each of them with duration and severity of vitiligo. In addition, patients with generalized vitiligo have significantly elevated serum migration inhibitory factor and mRNA levels than control subjects. Small number of investigated subjects. Migration inhibitory factor may have an active role in the development of vitiligo, and it may also be a useful index of disease severity. Consequently, migration inhibitory factor may be a new treatment target for vitiligo patients.

  3. A preliminary assessment of gas diffusion and migration

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-11-01

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

  4. 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...

  5. 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…

  6. Plan and progress of a cooperative research program on field migration test between CIRP and JAERI

    International Nuclear Information System (INIS)

    Li Shushen; Wang Zhiming; Li Zhentang

    1999-01-01

    As the main parts of a cooperative research project on safety assessment method for shallow land disposal of low level radioactive wastes between the China Institute for radiation Protection (CIRP) and the Japan Atomic Energy Research Institute (JAERI), field migration tests investigating the migration of radionuclides 90 Sr, 237 Np and 238 Pu and stable elements Sr, Ce, and Nd in both aerated zone and aquifer are carried out. 3 H and Br are used as tracers to obtain the water flow velocity in the aquifer and the movement of moisture water in the aerated zone for radioactive and non-radioactive tests, respectively. The aerated zone migration tests are carried out with media including soil, bentonite, cement block and mortar in both natural rainfall condition and artificial rainfall condition. The aquifer migration tests are carried out with assemblies (Type I), experimental frame (Type II) and injection tube (Type III), respectively, in and Underground Research Facility (URF). The aerated zone migration tests were started in May, 1997, while the aquifer migration tests started in August 1997. (author)

  7. [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.

  8. 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

  9. Emergy Evaluations of the Global Biogeochemical Cycles of Six Biologically Active Elements and Two Compounds

    Science.gov (United States)

    Estimates of the emergy carried by the flows of biologically active elements (BAE) and compounds are needed to accurately evaluate the near and far field effects of anthropogenic wastes. The transformities and specific emergies of these elements and of their different chemical sp...

  10. Evolution of cooperation driven by social-welfare-based migration

    Science.gov (United States)

    Li, Yan; Ye, Hang; Zhang, Hong

    2016-03-01

    Individuals' migration behavior may play a significant role in the evolution of cooperation. In reality, individuals' migration behavior may depend on their perceptions of social welfare. To study the relationship between social-welfare-based migration and the evolution of cooperation, we consider an evolutionary prisoner's dilemma game (PDG) in which an individual's migration depends on social welfare but not on the individual's own payoff. By introducing three important social welfare functions (SWFs) that are commonly studied in social science, we find that social-welfare-based migration can promote cooperation under a wide range of parameter values. In addition, these three SWFs have different effects on cooperation, especially through the different spatial patterns formed by migration. Because the relative efficiency of the three SWFs will change if the parameter values are changed, we cannot determine which SWF is optimal for supporting cooperation. We also show that memory capacity, which is needed to evaluate individual welfare, may affect cooperation levels in opposite directions under different SWFs. Our work should be helpful for understanding the evolution of human cooperation and bridging the chasm between studies of social preferences and studies of social cooperation.

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

    International Nuclear Information System (INIS)

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

    2005-09-01

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

  12. Stability and migration of vacancy in V–4Cr–4Ti alloy: Effects of Al, Si, Y trace elements

    International Nuclear Information System (INIS)

    Zhang, Chong; Zhang, Pengbo; Li, Ruihuan; Zhao, Jijun; Dong, Chuang

    2013-01-01

    Addition of trace amounts of Al, Si and Y into V–4Cr–4Ti alloy is beneficial for the mechanical properties under irradiation. It is thus important to investigate the influence of solute/trace elements on stabilities, energetics and diffusion behaviors of vacancy defects. We performed first-principles calculations to evaluate vacancy–solute/trace interaction inside dilute V–X (X = Ti, Cr, Al, Si, Y) and V–4Cr–4Ti–(Al, Si, Y) alloys. With addition of Si and Y, vacancy-based complexes tend to form near Ti–Si and Ti–Y pairs, while the effect of Al is negligible. Moreover, diffusion coefficients of solute/trace element in vanadium were derived using nine-frequency model. With high binding energy and low diffusion coefficient, Si atom is strongly attractive to vacancy in vanadium matrix. Our theoretical results suggest that the interactions between vacancy and solute/trace elements play some role in the evolution of microstructures inside vanadium alloys

  13. Some properties for modeling of fuel elements

    International Nuclear Information System (INIS)

    Nichols, F.A.

    1979-01-01

    Two areas key to the materials modeling of fuel element behavior are discussed. The relative importance of atomic diffusion vs. bubble migration is first surveyed and the interplay of bubble mobility and re-solution parameter is highlighted. It is concluded that biased bubble migration at higher temperatures is required to explain available gas-release data, especially during transients. At intermediate temperatures, random bubble migration is required to explain both gas-release rates and the observation of large (approx. 700A) intragranular bubbles following in-pile and post-irradiation transients. Different fuel models employ different values of re-solution parameter, both below and above an experimentally determined value. Bubble mobilities are deduced to approach theoretical, surface diffusion-controlled values during transients, but they may be somewhat less mobile during steady-state operation. Next, the present understanding of radiation-induced hardening and creep is discussed, highlighting the interplay of these two phenomena. An overall constitutive scheme is presented and predictions of failure limits are deduced therefrom employing instability analysis

  14. 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

  15. Influence of basalt/groundwater interactions on radionuclide migration

    International Nuclear Information System (INIS)

    Vandegrift, G.F.

    1984-01-01

    The work presented here is a partial summary of the experimental results obtained in the Laboratory Analog Program. Two aspects of this effort are (1) the interaction between simulated basaltic groundwater and basalt fissures that were either freshly cleaved or laboratory altered by hydrothermal treatment with the simulated groundwater and (2) the effect of this interaction on radionuclide migration through these basalt fissures. The following conclusions of this study bear heavily on the predicted safety of a basalt repository: Sorption properties of freshly fissured basalt and naturally aged basalt are quite different for different chemical species. Analog experiments predict that aged basalt would be an effective retarder of cesium, but would be much less so for actinide elements. Distribution ratios measured from batch experiments with finely ground rock samples (presenting unaltered rock surfaces) are not a reliable means of predicting radionuclide migration in geological repositories. As the near-repository area is resaturated by groundwater, its ability to retard actinide migration will be degraded with time. Disturbing the natural flow of groundwater through the repository area by constructing and backfilling the repository will modify the composition of groundwater. This modified groundwater is likely to interact with and to modify naturally aged basalt surfaces downstream from the repository

  16. Assessment of pesticide residues and trace element contamination ...

    African Journals Online (AJOL)

    ajl10

    It was based on the chemical analyses of soil, water and vegetable samples. ... of the fine fraction (under 2 mm) were conserved away from light for ... To assess the migration and accumulation of trace elements ..... metals from sewage sludge in an agricultural soil. ... Pesticides and heavy metals in drinking water, soils.

  17. Crosstalk between intracellular and extracellular signals regulating interneuron production migration and integration into the cortex

    Directory of Open Access Journals (Sweden)

    Elise ePeyre

    2015-04-01

    Full Text Available During embryogenesis, cortical interneurons are generated by ventral progenitors located in the ganglionic eminences of the telencephalon. They travel along multiple tangential paths to populate the cortical wall. As they reach this structure they undergo intracortical dispersion to settle in their final destination. At the cellular level, migrating interneurons are highly polarized cells that extend and retract processes using dynamic remodeling of microtubule and actin cytoskeleton. Different levels of molecular regulation contribute to interneuron migration. These include: 1/ Extrinsic guidance cues distributed along migratory streams that are sensed and integrated by migrating interneurons; 2/ Intrinsic genetic programs driven by specific transcription factors that grant specification and set the timing of migration for different subtypes of interneurons; 3/ Adhesion molecules and cytoskeletal elements/regulators that transduce molecular signalings into coherent movement. These levels of molecular regulation must be properly integrated by interneurons to allow their migration in the cortex. The aim of this review is to summarize our current knowledge of the interplay between microenvironmental signals and cell autonomous programs that drive cortical interneuron porduction, tangential migration, and intergration in the developing cerebral cortex.

  18. Reinventing US Internal Migration Studies in the Age of International Migration.

    Science.gov (United States)

    Ellis, Mark

    2012-03-01

    I argue that researchers have sidelined attention to issues raised by US internal migration as they shifted focus to the questions posed by the post-1960s rise in US immigration. In this paper, I offer some reasons about why immigration has garnered more attention and why there needs to be greater consideration of US internal migration and its significant and myriad social, economic, political, and cultural impacts. I offer three ideas for motivating more research into US internal geographic mobility that would foreground its empirical and conceptual connections to international migration. First, there should be more work on linked migration systems investigating the connections between internal and international flows. Second, the questions asked about immigrant social, cultural, and economic impacts and adaptations in host societies should also be asked about internal migrants. Third, and more generally, migration researchers should jettison the assumption that the national scale is the pre-eminent delimiter of migration types and processes. Some groups can move easily across borders; others are constrained in their moves within countries. These subnational scales and constraints will become more visible if migration research decentres the national from its theory and empirics.

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

    Directory of Open Access Journals (Sweden)

    Milan Palát

    2012-01-01

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

  20. Measurements of impurity migration in graphite at high temperatures using a proton microprobe

    International Nuclear Information System (INIS)

    Shroy, R.E.; Soo, P.; Sastre, C.A.; Schweiter, D.G.; Kraner, H.W.; Jones, K.W.

    1978-01-01

    The migration of fission products and other impurities through the graphite core of a High Temperature Gas Cooled Reactor is of prime importance in studies of reactor safety. Work in this area is being carried out in which graphite specimens are heated to temperatures up to 3800 0 C to induce migration of trace elements whose local concentrations are then measured with a proton microprobe. This instrument is a powerful device for such work because of its ability to determine concentrations at a part per million (ppm) level in a circular area as small as 10 μm while operating in an air environment. Studies show that Si, Ca, Cl, and Fe impurities in graphite migrate from hotter to cooler regions. Also Si, S, Cl, Ca, Fe, Mn, and Cr are observed to escape from the graphite and be deposited on cooler surfaces

  1. Statistical evaluation of characteristic SDDLV-induced stress resultants to discriminate between undamaged and damaged elements

    DEFF Research Database (Denmark)

    Hansen, Lasse Majgaard; Johansen, Rasmus Johan; Ulriksen, Martin Dalgaard

    2015-01-01

    of modified characteristic stress resultants, which are compared to a pre-defined tolerance value, without any thorough statistical evaluation. In the present paper, it is tested whether three widely-used statistical pattern-recognition-based damage-detection methods can provide an effective statistical...... evaluation of the characteristic stress resultants, hence facilitating general discrimination between damaged and undamaged elements. The three detection methods in question enable outlier analysis on the basis of, respectively, Euclidian distance, Hotelling’s statistics, and Mahalanobis distance. The study...... alternately to an undamaged reference model with known stiffness matrix, hereby, theoretically, yielding characteristic stress resultants approaching zero in the damaged elements. At present, the discrimination between potentially damaged elements and undamaged ones is typically conducted on the basis...

  2. 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.)

  3. Circumambulatory rearrangements of cyclopolyenes containing element-centred migrants

    International Nuclear Information System (INIS)

    Minkin, Vladimir I; Mikhailov, Igor E; Dushenko, Galina A; Zschunke, Adolf

    2003-01-01

    Data on circumambulatory rearrangements caused by rapid migrations of substituents formed by Group 13-17 elements around three- to nine-membered cyclopolyenes are generalised and systematised. Depending on the ring size, the nature of the migrating group, substituents in the ring and the medium, the rate constants of circumambulatory rearrangements vary over a wide range from 10 6 to 10 -8 s -1 at room temperature. Particular attention is given to analysis of the mechanisms of these rearrangements ([1, j]-, [2,3]- and [3,3]-sigmatropic shifts, haptotropic rearrangements and ionisation-recombination) and to the correlation of these mechanisms with the structural characteristics of the compounds that undergo rearrangements.

  4. Structural evaluation of the John A. Roebling Suspension Bridge : element level analysis.

    Science.gov (United States)

    2008-07-01

    The primary objective of the structural evaluation of the John A. Roebling Bridge is to determine the maximum allowable gross vehicle weight (GVW) that can be carried by the bridge deck structural elements such as the open steel grid deck, channels, ...

  5. Anisotropy signature in extended images from reverse-time migration

    KAUST Repository

    Sava, Paul

    2012-11-04

    Reverse-time migration can accurately image complex geologic structures in anisotropic media. Extended images at selected locations in the earth, i.e. at common-image-point gathers (CIPs), carry enough information to characterize the angle-dependent illumination and to provide measurements for migration velocity analysis. Furthermore, inaccurate anisotropy leaves a distinctive signature in CIPs, which can be used to evaluate anisotropy through techniques similar to the ones used in conventional wavefield tomography.

  6. Anisotropy signature in extended images from reverse-time migration

    KAUST Repository

    Sava, Paul; Alkhalifah, Tariq Ali

    2012-01-01

    Reverse-time migration can accurately image complex geologic structures in anisotropic media. Extended images at selected locations in the earth, i.e. at common-image-point gathers (CIPs), carry enough information to characterize the angle-dependent illumination and to provide measurements for migration velocity analysis. Furthermore, inaccurate anisotropy leaves a distinctive signature in CIPs, which can be used to evaluate anisotropy through techniques similar to the ones used in conventional wavefield tomography.

  7. Multistate modelling extended by behavioural rules: An application to migration.

    Science.gov (United States)

    Klabunde, Anna; Zinn, Sabine; Willekens, Frans; Leuchter, Matthias

    2017-10-01

    We propose to extend demographic multistate models by adding a behavioural element: behavioural rules explain intentions and thus transitions. Our framework is inspired by the Theory of Planned Behaviour. We exemplify our approach with a model of migration from Senegal to France. Model parameters are determined using empirical data where available. Parameters for which no empirical correspondence exists are determined by calibration. Age- and period-specific migration rates are used for model validation. Our approach adds to the toolkit of demographic projection by allowing for shocks and social influence, which alter behaviour in non-linear ways, while sticking to the general framework of multistate modelling. Our simulations yield that higher income growth in Senegal leads to higher emigration rates in the medium term, while a decrease in fertility yields lower emigration rates.

  8. THE IMPACT OF MIGRATION ON ROMANIA'S ECONOMICAL AND SOCIAL DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    DIANA-MIHAELA POCIOVĂLIȘTEANU

    2014-02-01

    Full Text Available Free movement for people is one of the most fundamental freedoms guaranteed by European Union law and it is a necessary precondition for building a single market. Greater adaptability on the part of workers through migration process is also a key element in making Europe Union more competitive at a global level, and at an individual level enabling employees to raise their skills levels and their employability, income and career prospects. In this paper I’m trying to review several aspects regarding the Romanian labour market, the causes that determined the labour force to emigrate in European Union’s member states, as well as migrations’ effects on the supply and demand on the labour market. Migration can have both positive and negative effects on economical and social life from the origin country.

  9. Hydrogeological modelling for migration of radioactivity

    International Nuclear Information System (INIS)

    Sunny, Faby; Chopra, Manish; Oza, R.B.

    2016-01-01

    The hydrogeological modelling for migration of radionuclides basically involves modelling of groundwater flow and contaminant transport through the groundwater. The water that occurs below the land surface or within the lithosphere is called groundwater. The groundwater constitutes about 4 % of the total water on the earth and about 30 % of freshwater on the earth. Groundwater models describe groundwater flow and contaminant transport processes using mathematical equations that are based on certain simplifying assumptions. These assumptions typically involve the direction of flow, geometry of the aquifer, the heterogeneity or anisotropy of sediments or bedrock within the aquifer, the contaminant transport mechanisms and chemical reactions. Because of the simplifying assumptions and the many uncertainties in the values of data, a model must be viewed as an approximation and not an exact duplication of field conditions. However, these models are useful investigation tool for a number of applications such as prediction of the possible fate and migration of contaminants for risk evaluation; tracking the possible pathway of groundwater contamination; evaluation of design of hydraulic containment and pump-and-treat systems; design of groundwater monitoring networks; evaluation of regional groundwater resources and prediction of the effect of future groundwater withdrawals on groundwater levels

  10. Understanding Migration as an Adaptation in Deltas Using a Bayesian Network Model

    Science.gov (United States)

    Lázár, A. N.; Adams, H.; de Campos, R. S.; Mortreux, C. C.; Clarke, D.; Nicholls, R. J.; Amisigo, B. A.

    2016-12-01

    Deltas are hotspots of high population density, fertile lands and dramatic environmental and anthropogenic pressures and changes. Amongst other environmental factors, sea level rise, soil salinization, water shortages and erosion threaten people's livelihoods and wellbeing. As a result, there is a growing concern that significant environmental change induced migration might occur from these areas. Migration, however, is already happening for economic, education and other reasons (e.g. livelihood change, marriage, planned relocation, etc.). Migration hence has multiple, interlinked drivers and depending on the perspective, can be considered as a positive or negative phenomenon. The DECCMA project (Deltas, Vulnerability & Climate Change: Migration & Adaptation) studies migration as part of a suite of adaptation options available to the coastal populations in the Ganges delta in Bangladesh, the Mahanadi delta in India and the Volta delta in Ghana. It aims to develop a holistic framework of analysis that assesses the impact of climate and environmental change on the migration patterns of these areas. This assessment framework will couple environmental, socio-economics and governance dimensions in an attempt to synthesise drivers and barriers and allow testing of plausible future scenarios. One of the integrative methods of DECCMA is a Bayesian Belief Network (BBN) model describing the decision-making of a coastal household. BBN models are built on qualitative and quantitative observations/expert knowledge and describe the probability of different events/responses etc. BBN models are especially useful to capture uncertainties of large systems and engaging with stakeholders. The DECCMA BBN model is based on household survey results from delta migrant sending areas. This presentation will describe model elements (livelihood sensitivity to climate change, local and national adaptation options, household characteristics/attitude, social networks, household decision) and

  11. Accuracy of specimen-specific nonlinear finite element analysis for evaluation of distal radius strength in cadaver material.

    Science.gov (United States)

    Matsuura, Yusuke; Kuniyoshi, Kazuki; Suzuki, Takane; Ogawa, Yasufumi; Sukegawa, Koji; Rokkaku, Tomoyuki; Takahashi, Kazuhisa

    2014-11-01

    Distal radius fracture, which often occurs in the setting of osteoporosis, can lead to permanent deformity and disability. Great effort has been directed toward developing noninvasive methods for evaluating the distal radius strength, with the goal of assessing fracture risk. The aim of this study was to evaluate distal radius strength using a finite element model and to gauge the accuracy of finite element model measurement using cadaver material. Ten wrists were obtained from cadavers with a mean age of 89.5 years at death. CT images of each wrist in an extended position were obtained. CT-based finite element models were prepared with Mechanical Finder software. Fracture on the models was simulated by applying a mechanical load to the palm in a direction parallel to the forearm axis, after which the fracture load and the site at which the fracture began were identified. For comparison, the wrists were fractured using a universal testing machine and the fracture load and the site of fracture were identified. The fracture load was 970.9 N in the finite element model group and 990.0 N in the actual measurement group. The site of the initial fracture was extra-articular to the distal radius in both groups. The finite element model was predictive for distal radius fracture when compared to the actual measurement. In this study, a finite element model for evaluation of distal radius strength was validated and can be used to predict fracture risk. We conclude that a finite element model is useful for the evaluation of distal radius strength. Knowing distal radius strength might avoid distal radius fracture because appropriate antiosteoporotic treatment can be initiated.

  12. Quasi-exact evaluation of time domain MFIE MOT matrix elements

    KAUST Repository

    Shi, Yifei; Bagci, Hakan; Shanker, Balasubramaniam; Lu, Mingyu; Michielssen, Eric

    2013-01-01

    A previously proposed quasi-exact scheme for evaluating matrix elements resulting from the marching-on-in-time (MOT) discretization of the time domain electric field integral equation (EFIE) is extended to matrix entries resulting from the discretization of its magnetic field integral equation (MFIE) counterpart. Numerical results demonstrate the accuracy of the scheme as well as the late-time stability of the resulting MOT-MFIE solver. © 2013 IEEE.

  13. Quasi-exact evaluation of time domain MFIE MOT matrix elements

    KAUST Repository

    Shi, Yifei

    2013-07-01

    A previously proposed quasi-exact scheme for evaluating matrix elements resulting from the marching-on-in-time (MOT) discretization of the time domain electric field integral equation (EFIE) is extended to matrix entries resulting from the discretization of its magnetic field integral equation (MFIE) counterpart. Numerical results demonstrate the accuracy of the scheme as well as the late-time stability of the resulting MOT-MFIE solver. © 2013 IEEE.

  14. 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 ...

  15. 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

  16. Understanding oceanic migrations with intrinsic biogeochemical markers.

    Directory of Open Access Journals (Sweden)

    Raül Ramos

    2009-07-01

    Full Text Available Migratory marine vertebrates move annually across remote oceanic water masses crossing international borders. Many anthropogenic threats such as overfishing, bycatch, pollution or global warming put millions of marine migrants at risk especially during their long-distance movements. Therefore, precise knowledge about these migratory movements to understand where and when these animals are more exposed to human impacts is vital for addressing marine conservation issues. Because electronic tracking devices suffer from several constraints, mainly logistical and financial, there is emerging interest in finding appropriate intrinsic markers, such as the chemical composition of inert tissues, to study long-distance migrations and identify wintering sites. Here, using tracked pelagic seabirds and some of their own feathers which were known to be grown at different places and times within the annual cycle, we proved the value of biogeochemical analyses of inert tissue as tracers of marine movements and habitat use. Analyses of feathers grown in summer showed that both stable isotope signatures and element concentrations can signal the origin of breeding birds feeding in distinct water masses. However, only stable isotopes signalled water masses used during winter because elements mainly accumulated during the long breeding period are incorporated into feathers grown in both summer and winter. Our findings shed new light on the simple and effective assignment of marine organisms to distinct oceanic areas, providing new opportunities to study unknown migration patterns of secretive species, including in relation to human-induced mortality on specific populations in the marine environment.

  17. Lung cells support osteosarcoma cell migration and survival.

    Science.gov (United States)

    Yu, Shibing; Fourman, Mitchell Stephen; Mahjoub, Adel; Mandell, Jonathan Brendan; Crasto, Jared Anthony; Greco, Nicholas Giuseppe; Weiss, Kurt Richard

    2017-01-25

    Osteosarcoma (OS) is the most common primary bone tumor, with a propensity to metastasize to the lungs. Five-year survival for metastatic OS is below 30%, and has not improved for several decades despite the introduction of multi-agent chemotherapy. Understanding OS cell migration to the lungs requires an evaluation of the lung microenvironment. Here we utilized an in vitro lung cell and OS cell co-culture model to explore the interactions between OS and lung cells, hypothesizing that lung cells would promote OS cell migration and survival. The impact of a novel anti-OS chemotherapy on OS migration and survival in the lung microenvironment was also examined. Three human OS cell lines (SJSA-1, Saos-2, U-2) and two human lung cell lines (HULEC-5a, MRC-5) were cultured according to American Type Culture Collection recommendations. Human lung cell lines were cultured in growth medium for 72 h to create conditioned media. OS proliferation was evaluated in lung co-culture and conditioned media microenvironment, with a murine fibroblast cell line (NIH-3 T3) in fresh growth medium as controls. Migration and invasion were measured using a real-time cell analysis system. Real-time PCR was utilized to probe for Aldehyde Dehydrogenase (ALDH1) expression. Osteosarcoma cells were also transduced with a lentivirus encoding for GFP to permit morphologic analysis with fluorescence microscopy. The anti-OS efficacy of Disulfiram, an ALDH-inhibitor previously shown to inhibit OS cell proliferation and metastasis in vitro, was evaluated in each microenvironment. Lung-cell conditioned medium promoted osteosarcoma cell migration, with a significantly higher attractive effect on all three osteosarcoma cell lines compared to basic growth medium, 10% serum containing medium, and NIH-3 T3 conditioned medium (p cell conditioned medium induced cell morphologic changes, as demonstrated with GFP-labeled cells. OS cells cultured in lung cell conditioned medium had increased alkaline

  18. Can finite element models detect clinically inferior cemented hip implants?

    NARCIS (Netherlands)

    Stolk, J.; Maher, S.A.; Verdonschot, N.J.J.; Prendergast, P.J.; Huiskes, R.

    2003-01-01

    Rigorous preclinical testing of cemented hip prostheses against the damage accumulation failure scenario will reduce the incidence of aseptic loosening. For that purpose, a finite element simulation is proposed that predicts damage accumulation in the cement mantle and prosthetic migration. If the

  19. Studying the migration behaviour of radionuclides in boom clay by electromigration

    Energy Technology Data Exchange (ETDEWEB)

    Norbert Maes, H.; Moors, H.; Dierckx, A.; Aertsens, M.; Wang, L.; Canniere, P. de; Put, M. [SCK-CEN, Belgian Nuclear Research Centre, Waste and Disposal - R and D Geological Disposal Mol (Belgium)

    2001-07-01

    Migration studies are an important part in the assessment of the performance of the Boom Clay Formation as a candidate for geological disposal of High-Level radwaste in Belgium. However, classical diffusion experiments take a long time because of the excellent retention characteristics of the Boom Clay. Electrical fields can be used to move ionic species. Especially for low permeability soils/sediments (such as clays), this driving force is far more efficient than a hydraulic gradient. As a consequence, the experimental time can be reduced drastically. This paper gives an overview on the quantitative and qualitative use of electromigration as a powerful technique to study radionuclides migration in clays. The enormous time gain in the determination of migration parameters for strongly retarded radionuclides as {sup 137}Cs{sup +} and {sup 226}Ra{sup 2+} is first demonstrated. Secondly, we want to demonstrate that electromigration has some useful features to study the behaviour of radionuclides with a more complex chemistry like the redox sensitive element uranium and Am-Organic Matter (OM) complexes. In the case of uranium, electromigration provides information on the speciation of the migrating species while for the Am-organic Matter complexes the role of OM as a possible carrier of actinides is investigated. (orig.)

  20. Studying the migration behaviour of radionuclides in boom clay by electromigration

    International Nuclear Information System (INIS)

    Norbert Maes, H.; Moors, H.; Dierckx, A.; Aertsens, M.; Wang, L.; Canniere, P. de; Put, M.

    2001-01-01

    Migration studies are an important part in the assessment of the performance of the Boom Clay Formation as a candidate for geological disposal of High-Level radwaste in Belgium. However, classical diffusion experiments take a long time because of the excellent retention characteristics of the Boom Clay. Electrical fields can be used to move ionic species. Especially for low permeability soils/sediments (such as clays), this driving force is far more efficient than a hydraulic gradient. As a consequence, the experimental time can be reduced drastically. This paper gives an overview on the quantitative and qualitative use of electromigration as a powerful technique to study radionuclides migration in clays. The enormous time gain in the determination of migration parameters for strongly retarded radionuclides as 137 Cs + and 226 Ra 2+ is first demonstrated. Secondly, we want to demonstrate that electromigration has some useful features to study the behaviour of radionuclides with a more complex chemistry like the redox sensitive element uranium and Am-Organic Matter (OM) complexes. In the case of uranium, electromigration provides information on the speciation of the migrating species while for the Am-organic Matter complexes the role of OM as a possible carrier of actinides is investigated. (orig.)

  1. Meisoindigo, but not its core chemical structure indirubin, inhibits zebrafish interstitial leukocyte chemotactic migration.

    Science.gov (United States)

    Ye, Baixin; Xiong, Xiaoxing; Deng, Xu; Gu, Lijuan; Wang, Qiongyu; Zeng, Zhi; Gao, Xiang; Gao, Qingping; Wang, Yueying

    2017-12-01

    Inflammatory disease is a big threat to human health. Leukocyte chemotactic migration is required for efficient inflammatory response. Inhibition of leukocyte chemotactic migration to the inflammatory site has been shown to provide therapeutic targets for treating inflammatory diseases. Our study was designed to discover effective and safe compounds that can inhibit leukocyte chemotactic migration, thus providing possible novel therapeutic strategy for treating inflammatory diseases. In this study, we used transgenic zebrafish model (Tg:zlyz-EGFP line) to visualize the process of leukocyte chemotactic migration. Then, we used this model to screen the hit compound and evaluate its biological activity on leukocyte chemotactic migration. Furthermore, western blot analysis was performed to evaluate the effect of the hit compound on the AKT or ERK-mediated pathway, which plays an important role in leukocyte chemotactic migration. In this study, using zebrafish-based chemical screening, we identified that the hit compound meisoindigo (25 μM, 50 μM, 75 μM) can significantly inhibit zebrafish leukocyte chemotactic migration in a dose-dependent manner (p = 0.01, p = 0.0006, p migration (p = 0.43). Furthermore, our results unexpectedly showed that indirubin, the core structure of meisoindigo, had no significant effect on zebrafish leukocyte chemotactic migration (p = 0.6001). Additionally, our results revealed that meisoindigo exerts no effect on the Akt or Erk-mediated signalling pathway. Our results suggest that meisoindigo, but not indirubin, is effective for inhibiting leukocyte chemotactic migration, thus providing a potential therapeutic agent for treating inflammatory diseases.

  2. 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.

  3. Testing the effects of the numerical implementation of water migration on models of subduction dynamics

    Science.gov (United States)

    Quinquis, M. E. T.; Buiter, S. J. H.

    2013-10-01

    Subduction of oceanic lithosphere brings water into Earth's upper mantle. Previous numerical studies have shown how slab dehydration and mantle hydration can impact the dynamics of a subduction system by allowing a more vigorous mantle flow and promoting localisation of deformation in lithosphere and mantle. The depths at which dehydration reactions occur in the hydrated portions of the slab are well constrained in these models by thermodynamic calculations. However, the mechanism by which free water migrates in the mantle is incompletely known. Therefore, models use different numerical schemes to model the migration of free water. We aim to show the influence of the numerical scheme of free water migration on the dynamics of the upper mantle and more specifically the mantle wedge. We investigate the following three migration schemes with a finite-element model: (1) element-wise vertical migration of free water, occurring independent of the material flow; (2) an imposed vertical free water velocity; and (3) a Darcy velocity, where the free water velocity is calculated as a function of the pressure gradient between water and the surrounding rocks. In addition, the material flow field also moves the free water in the imposed vertical velocity and Darcy schemes. We first test the influence of the water migration scheme using a simple Stokes flow model that simulates the sinking of a cold hydrated cylinder into a hot dry mantle. We find that the free water migration scheme has only a limited impact on the water distribution after 1 Myr in these models. We next investigate slab dehydration and mantle hydration with a thermomechanical subduction model that includes brittle behaviour and viscous water-dependent creep flow laws. Our models show how the bound water distribution is not greatly influenced by the water migration scheme whereas the free water distribution is. We find that a water-dependent creep flow law results in a broader area of hydration in the mantle

  4. Research on the Core Competitive Power Elements Evaluation System of Green Hotel

    OpenAIRE

    Hui LIANG

    2013-01-01

    Green hotel is a new type of hospitality industry development model based on the concept of circular economy and sustainable development. This paper makes an analysis and evaluation of the elements of green hotel core competence, on this basis, constructs the Green Hotel core competitive evaluation index system. The construction of the system is conducive to understand the green hotel’s own competitive advantage objectively, and explore ways to enhance its core competitiveness, providing obje...

  5. Evaluation of the attenuating properties of selected Greek clays for toxic inorganic elements in landfill sites.

    Science.gov (United States)

    Mimides, T; Perraki, T

    2000-05-15

    Heavy metal attenuation properties of selected clay material collected from miscellaneous Greek sites is investigated and tested in the laboratory for their suitability, either as liners in hydrologically unsafe sites or as earth covers for sanitary landfill sites. Eleven potentially hazardous elements (As, Be, Cd, Cr, Cu, Hg, Ni, Pb, Se, V, and Zn) generated by a co-disposal landfill leachate have been considered. Experimental column and static equilibrium methods for the determination of dispersion and adsorption are described. Molecular diffusion dominates the migration phenomena with a velocity range between 1.3 x 10(-5) and 3.5 x 10(-4) cm/s throughout the experiments. A simple way to evaluate dispersion coefficients from breakthrough curves gave values of between 3.90 x 10(-6) and 3.5 x 10(-4) cm2/s, with a mean value of 1.5 x 10(-5). Static adsorption equilibrium studies supported by column runs showed that Freundlich (F = kCn) isotherms express in a better way the assimilative capacities of the tested clays, with k and n values ranging from 0.06 to 1.99 and 0.55 to 1.48 correspondingly. Mathematical models involving non-linear parabolic equations are involved. The experimental data, together with finite difference techniques and some physical clay characteristics, produced trilinear textural diagrams and predictive flow transport convection-dispersion breakthrough curves for a quick estimation of the attenuating properties of clays for heavy metals.

  6. 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,

  7. Calcium-containing scaffolds induce bone regeneration by regulating mesenchymal stem cell differentiation and migration.

    Science.gov (United States)

    Aquino-Martínez, Rubén; Angelo, Alcira P; Pujol, Francesc Ventura

    2017-11-16

    Osteoinduction and subsequent bone formation rely on efficient mesenchymal stem cell (MSC) recruitment. It is also known that migration is induced by gradients of growth factors and cytokines. Degradation of Ca 2+ -containing biomaterials mimics the bone remodeling compartment producing a localized calcium-rich osteoinductive microenvironment. The aim of our study was to determine the effect of calcium sulfate (CaSO 4 ) on MSC migration. In addition, to evaluate the influence of CaSO 4 on MSC differentiation and the potential molecular mechanisms involved. A circular calvarial bone defect (5 mm diameter) was created in the parietal bone of 35 Balb-C mice. We prepared and implanted a cell-free agarose/gelatin scaffold alone or in combination with different CaSO 4 concentrations into the bone defects. After 7 weeks, we determined the new bone regenerated by micro-CT and histological analysis. In vitro, we evaluated the CaSO 4 effects on MSC migration by both wound healing and agarose spot assays. Osteoblastic gene expression after BMP-2 and CaSO 4 treatment was also evaluated by qPCR. CaSO 4 increased MSC migration and bone formation in a concentration-dependent manner. Micro-CT analysis showed that the addition of CaSO 4 significantly enhanced bone regeneration compared to the scaffold alone. The histological evaluation confirmed an increased number of endogenous cells recruited into the cell-free CaSO 4 -containing scaffolds. Furthermore, MSC migration in vitro and active AKT levels were attenuated when CaSO 4 and BMP-2 were in combination. Addition of LY294002 and Wortmannin abrogated the CaSO 4 effects on MSC migration. Specific CaSO 4 concentrations induce bone regeneration of calvarial defects in part by acting on the host's undifferentiated MSCs and promoting their migration. Progenitor cell recruitment is followed by a gradual increment in osteoblast gene expression. Moreover, CaSO 4 regulates BMP-2-induced MSC migration by differentially activating the PI3

  8. Long-time safety aspects of ultimate storage of transuranium elements

    International Nuclear Information System (INIS)

    Storck, R.

    1992-10-01

    Based on the amounts of transuranium elements generated in nuclear reactors, the inventories of these elements in the repository are described for various ultimate disposal strategies. The data are used to give an outline description of accident-induced ingress of brines into the backfilled repository shaft during the post-closure period and the resulting mechanisms of a mobilization of the transuranium elements and their escape from the repository, and to calculate amounts released. The effects of the released transuranium elements on the biosphere and the different contributions of the various isotopes to the calculated radiation exposure are given as an estimate and are described in more detail by means of data determined by parameter variation. The effects of transuranium elements during the entire migration process are restricted to the production of daughter nuclides, especially of the uranium isotopes. They give no particular contribution to environmental radiation exposure because of their low mobility. With the only exception of Np-237 which, due to its long half-time and relatively good migration capacity, can reach the biosphere. The contributions of the transuranium elements to the dose maxima, caused by the daughter products, of the uranium isotopes or the neptunium are calculated to be about 50%. All publications to date presenting a safety analysis of the site of the Gorleben repository assume the dose maxima of all uranium isotopes together to be approx. 10%, and those of the neptunium isotope approx. 20%, referring to the most significant fission products. This indicates that uranium or neptunium are of secondary significance in the process, and the other transuranium elements are only third-rate. (orig./HP) [de

  9. Evaluation of periprosthetic bone mineral density and postoperative migration of humeral head resurfacing implants

    DEFF Research Database (Denmark)

    Mechlenburg, Inger; Klebe, Thomas Martin; Døssing, Kaj Verner

    2014-01-01

    BACKGROUND: Implant migration, bone mineral density (BMD), length of glenohumeral offset (LGHO), and clinical results were compared for the Copeland (Biomet Inc, Warsaw, IN, USA) and the Global C.A.P. (DePuy Int, Warsaw, IN, USA) humeral head resurfacing implants (HHRIs). METHODS: The study...... improved over time for both implant groups (P migration and good clinical results. Periprosthetic BMD and LGHO both increased for the Copeland HHRI more than for the Global C.A.P HHRI....

  10. Pseudomonas aeruginosa ExoU augments neutrophil transepithelial migration.

    Science.gov (United States)

    Pazos, Michael A; Lanter, Bernard B; Yonker, Lael M; Eaton, Alex D; Pirzai, Waheed; Gronert, Karsten; Bonventre, Joseph V; Hurley, Bryan P

    2017-08-01

    Excessive neutrophil infiltration of the lungs is a common contributor to immune-related pathology in many pulmonary disease states. In response to pathogenic infection, airway epithelial cells produce hepoxilin A3 (HXA3), initiating neutrophil transepithelial migration. Migrated neutrophils amplify this recruitment by producing a secondary gradient of leukotriene B4 (LTB4). We sought to determine whether this two-step eicosanoid chemoattractant mechanism could be exploited by the pathogen Pseudomonas aeruginosa. ExoU, a P. aeruginosa cytotoxin, exhibits phospholipase A2 (PLA2) activity in eukaryotic hosts, an enzyme critical for generation of certain eicosanoids. Using in vitro and in vivo models of neutrophil transepithelial migration, we evaluated the impact of ExoU expression on eicosanoid generation and function. We conclude that ExoU, by virtue of its PLA2 activity, augments and compensates for endogenous host neutrophil cPLA2α function, leading to enhanced transepithelial migration. This suggests that ExoU expression in P. aeruginosa can circumvent immune regulation at key signaling checkpoints in the neutrophil, resulting in exacerbated neutrophil recruitment.

  11. Pseudomonas aeruginosa ExoU augments neutrophil transepithelial migration.

    Directory of Open Access Journals (Sweden)

    Michael A Pazos

    2017-08-01

    Full Text Available Excessive neutrophil infiltration of the lungs is a common contributor to immune-related pathology in many pulmonary disease states. In response to pathogenic infection, airway epithelial cells produce hepoxilin A3 (HXA3, initiating neutrophil transepithelial migration. Migrated neutrophils amplify this recruitment by producing a secondary gradient of leukotriene B4 (LTB4. We sought to determine whether this two-step eicosanoid chemoattractant mechanism could be exploited by the pathogen Pseudomonas aeruginosa. ExoU, a P. aeruginosa cytotoxin, exhibits phospholipase A2 (PLA2 activity in eukaryotic hosts, an enzyme critical for generation of certain eicosanoids. Using in vitro and in vivo models of neutrophil transepithelial migration, we evaluated the impact of ExoU expression on eicosanoid generation and function. We conclude that ExoU, by virtue of its PLA2 activity, augments and compensates for endogenous host neutrophil cPLA2α function, leading to enhanced transepithelial migration. This suggests that ExoU expression in P. aeruginosa can circumvent immune regulation at key signaling checkpoints in the neutrophil, resulting in exacerbated neutrophil recruitment.

  12. Characterisation and potential migration of silver nanoparticles from commercially available polymeric food contact materials.

    Science.gov (United States)

    Addo Ntim, Susana; Thomas, Treye A; Begley, Timothy H; Noonan, Gregory O

    2015-01-01

    The potential for consumer exposure to nano-components in food contact materials (FCMs) is dependent on the migration of nanomaterials into food. Therefore, characterising the physico-chemical properties and potential for migration of constituents is an important step in assessing the safety of FCMs. A number of commercially available food storage products, purchased domestically within the United States and internationally, that claim to contain nanosilver were evaluated. The products were made of polyethylene, polypropylene and polyphenylene ether sulfone and all contained silver (0.001-36 mg kg(-1) of polymer). Silver migration was measured under various conditions, including using 3% acetic acid and water as food simulants. Low concentrations (sub-ppb levels) of silver were detected in the migration studies generally following a trend characterised by a surface desorption phenomenon, where the majority of the silver migration occurred in the first of three consecutive exposures. Silver nanoparticles were not detected in food simulants, suggesting that the silver migration may be due solely to ionic silver released into solution from oxidation of the silver nanoparticle surface. The absence of detectable silver nanoparticles was consistent with expectations from a physico-chemical view point. For the products tested, current USFDA guidance for evaluating migration from FCMs was applicable.

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

    Science.gov (United States)

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

    2017-09-01

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

  14. 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...

  15. Effect of shear stress on the migration of hepatic stellate cells.

    Science.gov (United States)

    Sera, Toshihiro; Sumii, Tateki; Fujita, Ryosuke; Kudo, Susumu

    2018-01-01

    When the liver is damaged, hepatic stellate cells (HSCs) can change into an activated, highly migratory state. The migration of HSCs may be affected by shear stress due not only to sinusoidal flow but also by the flow in the space of Disse because this space is filled with blood plasma. In this study, we evaluated the effects of shear stress on HSC migration in a scratch-wound assay with a parallel flow chamber. At regions upstream of the wound area, the migration was inhibited by 0.6 Pa and promoted by 2.0 Pa shear stress, compared to the static condition. The platelet-derived growth factor (PDGF)-BB receptor, PDGFR-β, was expressed in all conditions and the differences were not significant. PDGF increased HSC migration, except at 0.6 Pa shear stress, which was still inhibited. These results indicate that another molecular factor, such as PDGFR-α, may act to inhibit the migration under low shear stress. At regions downstream of the wound area, the migration was smaller under shear stress than under the static condition, although the expression of PDGFR-β was significantly higher. In particular, the migration direction was opposite to the wound area under high shear stress; therefore, migration might be influenced by the intercellular environment. Our results indicate that HSC migration was influenced by shear stress intensity and the intercellular environment.

  16. U.S. Department of Energy approaches to the assessment of radionuclide migration for the geologic repository program

    International Nuclear Information System (INIS)

    Luik, A.E. van; Apted, M.J.

    1988-01-01

    Potential radionuclide migration in geologic repositories is being addressed by the U.S. Department of Energy's Office of Civilian Radioactive Waste Management through its Office of Geologic Repositories (OGR). A diversity of geohydrologic settings is being investigated: unsaturated tuff, saturated basalt, and bedded salt. A number of approaches to assessing potential migration are being considered. Mass transfer is prominent among near-field approaches. For far-field analysis of migration in the geosphere, detailed characterizations of potential repository sites will lead to site-specific models describing radionuclide migration for a variety of postulated release scenarios. Finite-element and finite-difference codes are being used and developed to solve the mathematical equations pertinent to far-field assessments. Computational approaches presently in use generally require distribution coefficients to estimate the retardation of specific radionuclides with respect to the transport rate of water. 26 refs

  17. Conservation physiology of animal migration

    Science.gov (United States)

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

    2016-01-01

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

  18. 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.

  19. DESIGNING THE RETURN MIGRATION OF ROMANIAN STUDENTS

    Directory of Open Access Journals (Sweden)

    Magdalena VELCIU

    2017-05-01

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

  20. 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...

  1. Modeling Studies to Constrain Fluid and Gas Migration Associated with Hydraulic Fracturing Operations

    Science.gov (United States)

    Rajaram, H.; Birdsell, D.; Lackey, G.; Karra, S.; Viswanathan, H. S.; Dempsey, D.

    2015-12-01

    The dramatic increase in the extraction of unconventional oil and gas resources using horizontal wells and hydraulic fracturing (fracking) technologies has raised concerns about potential environmental impacts. Large volumes of hydraulic fracturing fluids are injected during fracking. Incidents of stray gas occurrence in shallow aquifers overlying shale gas reservoirs have been reported; whether these are in any way related to fracking continues to be debated. Computational models serve as useful tools for evaluating potential environmental impacts. We present modeling studies of hydraulic fracturing fluid and gas migration during the various stages of well operation, production, and subsequent plugging. The fluid migration models account for overpressure in the gas reservoir, density contrast between injected fluids and brine, imbibition into partially saturated shale, and well operations. Our results highlight the importance of representing the different stages of well operation consistently. Most importantly, well suction and imbibition both play a significant role in limiting upward migration of injected fluids, even in the presence of permeable connecting pathways. In an overall assessment, our fluid migration simulations suggest very low risk to groundwater aquifers when the vertical separation from a shale gas reservoir is of the order of 1000' or more. Multi-phase models of gas migration were developed to couple flow and transport in compromised wellbores and subsurface formations. These models are useful for evaluating both short-term and long-term scenarios of stray methane release. We present simulation results to evaluate mechanisms controlling stray gas migration, and explore relationships between bradenhead pressures and the likelihood of methane release and transport.

  2. Modelling gas migration in compacted bentonite: GAMBIT Club Phase 2. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Swift, B.T.; Hoch, A.R.; Rodwell, W.R. [AEA Technology (United Kingdom)

    2001-01-01

    This report describes the second phase of a programme of work to develop a computational model of gas migration through highly compacted bentonite. Experimental data that have appeared since the earlier report are reviewed for the additional information they might provide on the mechanism of gas migration in bentonite. Experiments carried out by Horseman and Harrigton (British Geological Survey) continued to provide the main data sets used in model evaluation. The earlier work (POSIVA Report 98-08) had resulted in a preliminary model of gas migration whose main features are gas invasion by microcrack propagation, and dilation of the pathways formed with increasing gas pressure. New work was carried out to further explore the capabilities of this model. In addition, a feature was added to the model to simulate gas pathway creation by water displacement rather than crack propagation. The development of a new alternative gas migration model is described. This is based on a volume-averaged representation of gas migration rather than on a description of flow in discrete pathways. Evaluation of this alternative model showed that it can produce similar agreement with experimental results to the other models examined. The implications of flow geometry, confining conditions and flow boundary conditions on gas migration behaviour in bentonite are reviewed. Proposals are made for the development of the new model into a tool for simulating gas migration through a bentonite buffer around a waste canister, and for possible enhancements to the model that might remove some of its currently perceived deficiencies. (orig.)

  3. Climate of migration? How climate triggered migration from southwest Germany to North America during the 19th century

    Science.gov (United States)

    Glaser, Rüdiger; Himmelsbach, Iso; Bösmeier, Annette

    2017-11-01

    This paper contributes to the ongoing debate on the extent to which climate and climatic change can have a negative impact on societies by triggering migration, or even contribute to conflict. It summarizes results from the transdisciplinary project Climate of migration (funded 2010-2014), whose innovative title was created by Franz Mauelshagen and Uwe Lübken. The overall goal of this project was to analyze the relation between climatic and socioeconomic parameters and major migration waves from southwest Germany to North America during the 19th century. The article assesses the extent to which climatic conditions triggered these migration waves. The century investigated was in general characterized by the Little Ice Age with three distinct cooling periods, causing major glacier advances in the alpine regions and numerous climatic extremes such as major floods, droughts and severe winter. Societal changes were tremendous, marked by the warfare during the Napoleonic era (until 1815), the abolition of serfdom (1817), the bourgeois revolution (1847/48), economic freedom (1862), the beginning of industrialization accompanied by large-scale rural-urban migration resulting in urban poverty, and finally by the foundation of the German Empire in 1871.The presented study is based on quantitative data and a qualitative, information-based discourse analysis. It considers climatic conditions as well as socioeconomic and political issues, leading to the hypothesis of a chain of effects ranging from unfavorable climatic conditions to a decrease in crop yields to rising cereal prices and finally to emigration. These circumstances were investigated extensively for the peak emigration years identified with each migration wave. Furthermore, the long-term relations between emigration and the prevailing climatic conditions, crop yields and cereal prices were statistically evaluated with a sequence of linear models which were significant with explanatory power between 22 and 38 %.

  4. Fundamental aspects of nuclear reactor fuel elements

    International Nuclear Information System (INIS)

    Olander, D.R.

    1976-01-01

    The book presented is designed to function both as a text for first-year graduate courses in nuclear materials and as a reference for workers involved in the materials design and performance aspects of nuclear power plants. The contents are arranged under the following chapter headings: statistical thermodynamics, thermal properties of solids, crystal structures, cohesive energy of solids, chemical equilibrium, point defects in solids, diffusion in solids, dislocations and grain boundaries, equation of state of UO 2 , fuel element thermal performance, fuel chemistry, behavior of solid fission products in oxide fuel elements, swelling due to fission gases, pore migration and fuel restructuring kinetics, fission gas release, mechanical properties of UO 2 , radiation damage, radiation effects in metals, interaction of sodium and stainless steel, modeling of the structural behavior of fuel elements and assemblies

  5. Micromechanical investigation of sand migration in gas hydrate-bearing sediments

    Science.gov (United States)

    Uchida, S.; Klar, A.; Cohen, E.

    2017-12-01

    Past field gas production tests from hydrate bearing sediments have indicated that sand migration is an important phenomenon that needs to be considered for successful long-term gas production. The authors previously developed the continuum based analytical thermo-hydro-mechanical sand migration model that can be applied to predict wellbore responses during gas production. However, the model parameters involved in the model still needs to be calibrated and studied thoroughly and it still remains a challenge to conduct well-defined laboratory experiments of sand migration, especially in hydrate-bearing sediments. Taking the advantage of capability of micromechanical modelling approach through discrete element method (DEM), this work presents a first step towards quantifying one of the model parameters that governs stresses reduction due to grain detachment. Grains represented by DEM particles are randomly removed from an isotropically loaded DEM specimen and statistical analyses reveal that linear proportionality exists between the normalized volume of detached solids and normalized reduced stresses. The DEM specimen with different porosities (different packing densities) are also considered and statistical analyses show that there is a clear transition between loose sand behavior and dense sand behavior, characterized by the relative density.

  6. Computed tomography in the evaluation of migrational disorders of the brain. 1

    International Nuclear Information System (INIS)

    Byrd, S.E.; Bohan, T.P.; Osborn, R.E.

    1988-01-01

    The migrational disorders are a rare group of congenital malformations of the brain which are almost exclusively seen in children. They are comprised of four types, lissencephaly, schizencephaly, heterotopia and polymicrogyria. They have received little attention in the radiology literature because until recently the radiographic modalities to evaluate these disorders (which are primarily abnormalities of the cortex of the brain (gyri and sulci) and gray matter) were not available. Advanced CT scanners have allowed better resolution of the pediatric brain, and in turn better delineation of this group of congenital malformations. The development of the neocortex of the brain is reviewed and the entity of lissencephaly is emphasized. The characteristic CT appearance of lissencephaly is discussed with a delineation of the major findings of (1) agyric-pachygyric cortex (2) shallow sylvian grooves producing a 'figure of eight' appearance and (3) thickened cortical gray matter with loss of the gray-white matter interdigitations. A classification of lissencephaly is proposed, based on the 13 patients of this study and the patients' reviews in the medical literature. 24 refs.; 8 figs.; 3 tabs

  7. The percentage of migration as indicator of femoral head position

    International Nuclear Information System (INIS)

    Ekloef, O.; Ringertz, H.; Samuelsson, L.; Karolinska Sjukhuset, Stockholm; Karolinska Sjukhuset, Stockholm

    1988-01-01

    In childhood subluxation of one or both hips may develop rather insidiously. For lack of generally accepted objective methods of assessment, ambiguous interpretations of findings in serial examinations are common. Many subluxations are overlooked during the early stages. In order to overcome such disadvantages, determination of the percentage of migration seems to be a reasonably easy and reliable technique facilitating evaluation of impending dislocation. This investigation was carried out in order to estabilsh norms applicable to patients in the pediatric age interval. The 98th percentile of migration increases with age from 16% in patients < 4 years of age to 24% in patients ≥ 12 years. Higher figures represent subluxation. If the migration exceeds 80% a manifest luxation is present. A difference in migration between the two hips larger than 12% indicates abnormality calling for clinical and radiologic follow-up. (orig.)

  8. 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

  9. 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.

  10. On the migration of uranium isotopes in sandstone aquifers

    International Nuclear Information System (INIS)

    Froehlich, K.; Gellermann, R.

    1982-01-01

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

  11. A simple gamma spectrometry method for evaluating the burnup of MTR-type HEU fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Makmal, T. [The Unit of Nuclear Engineering, Ben-Gurion University of The Negev, Beer-Sheva 84105 (Israel); Nuclear Physics and Engineering Division, Soreq Nuclear Research Center, Yavne 81800 (Israel); Aviv, O. [Radiation Safety Division, Soreq Nuclear Research Center, Yavne 81800 (Israel); Gilad, E., E-mail: gilade@bgu.ac.il [The Unit of Nuclear Engineering, Ben-Gurion University of The Negev, Beer-Sheva 84105 (Israel)

    2016-10-21

    A simple method for the evaluation of the burnup of a materials testing reactor (MTR) fuel element by gamma spectrometry is presented. The method was applied to a highly enriched uranium MTR nuclear fuel element that was irradiated in a 5 MW pool-type research reactor for a total period of 34 years. The experimental approach is based on in-situ measurements of the MTR fuel element in the reactor pool by a portable high-purity germanium detector located in a gamma cell. To corroborate the method, analytical calculations (based on the irradiation history of the fuel element) and computer simulations using a dedicated fuel cycle burnup code ORIGEN2 were performed. The burnup of the MTR fuel element was found to be 52.4±8.8%, which is in good agreement with the analytical calculations and the computer simulations. The method presented here is suitable for research reactors with either a regular or an irregular irradiation regime and for reactors with limited infrastructure and/or resources. In addition, its simplicity and the enhanced safety it confers may render this method suitable for IAEA inspectors in fuel element burnup assessments during on-site inspections. - Highlights: • Simple, inexpensive, safe and flexible experimental setup that can be quickly deployed. • Experimental results are thoroughly corroborated against ORIGEN2 burnup code. • Experimental uncertainty of 9% and 5% deviation between measurements and simulations. • Very high burnup MTR fuel element is examined, with 60% depletion of {sup 235}U. • Impact of highly irregular irradiation regime on burnup evaluation is studied.

  12. Studies of the physico-chemical properties on the transuranian elements in connection with the migration phenomenon in the geosphere. Task 3 Characterization of radioactive waste forms. A series of final reports (1985-89)

    International Nuclear Information System (INIS)

    Vitorge, P.; Oliver, J.; Mangin, J.P.; Billon, A.

    1991-01-01

    In the first part, the properties of the transuranium elements (TRU) mainly Pu Np Am have been investigated in terms of complexation by OH and CO3 ligands in aqueous solution. The species which are formed in given physicochemical conditions (ionic strength, concentrations...) are studied with no direct reference to well defined ground waters. Equilibrium constants of complexes and redox potential values are useful in the drawing up of Pourbaix's diagrams. Areas of stability of species in function of Eh pH pCO2 are given for the different elements in a few cases. The second part of this report deals with the study of the transfer of tritiated water cesium and strontium through highly compacted clay (diffusion coefficient). In a third part a code for the computation of ion migration and diffusion in areas close to radwaste storage facilities has been developed. This type of application was found to require a mesh pattern and boundary conditions different from the usual, which justifies the writing of a new code called CONDIMENT. (Convection and Diffusion of elements) 49 figs.; 18 tabs.; 21 refs

  13. The Reverse Time Migration technique coupled with Interior Penalty Discontinuous Galerkin method.

    Science.gov (United States)

    Baldassari, C.; Barucq, H.; Calandra, H.; Denel, B.; Diaz, J.

    2009-04-01

    Seismic imaging is based on the seismic reflection method which produces an image of the subsurface from reflected waves recordings by using a tomography process and seismic migration is the industrial standard to improve the quality of the images. The migration process consists in replacing the recorded wavefields at their actual place by using various mathematical and numerical methods but each of them follows the same schedule, according to the pioneering idea of Claerbout: numerical propagation of the source function (propagation) and of the recorded wavefields (retropropagation) and next, construction of the image by applying an imaging condition. The retropropagation step can be realized accouting for the time reversibility of the wave equation and the resulting algorithm is currently called Reverse Time Migration (RTM). To be efficient, especially in three dimensional domain, the RTM requires the solution of the full wave equation by fast numerical methods. Finite element methods are considered as the best discretization method for solving the wave equation, even if they lead to the solution of huge systems with several millions of degrees of freedom, since they use meshes adapted to the domain topography and the boundary conditions are naturally taken into account in the variational formulation. Among the different finite element families, the spectral element one (SEM) is very interesting because it leads to a diagonal mass matrix which dramatically reduces the cost of the numerical computation. Moreover this method is very accurate since it allows the use of high order finite elements. However, SEM uses meshes of the domain made of quadrangles in 2D or hexaedra in 3D which are difficult to compute and not always suitable for complex topographies. Recently, Grote et al. applied the IPDG (Interior Penalty Discontinuous Galerkin) method to the wave equation. This approach is very interesting since it relies on meshes with triangles in 2D or tetrahedra in 3D

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

    Science.gov (United States)

    Traore, S

    1997-10-01

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

  16. A Review on Migration Methods in B-Scan Ground Penetrating Radar Imaging

    Directory of Open Access Journals (Sweden)

    Caner Özdemir

    2014-01-01

    Full Text Available Even though ground penetrating radar has been well studied and applied by many researchers for the last couple of decades, the focusing problem in the measured GPR images is still a challenging task. Although there are many methods offered by different scientists, there is not any complete migration/focusing method that works perfectly for all scenarios. This paper reviews the popular migration methods of the B-scan GPR imaging that have been widely accepted and applied by various researchers. The brief formulation and the algorithm steps for the hyperbolic summation, the Kirchhoff migration, the back-projection focusing, the phase-shift migration, and the ω-k migration are presented. The main aim of the paper is to evaluate and compare the migration algorithms over different focusing methods such that the reader can decide which algorithm to use for a particular application of GPR. Both the simulated and the measured examples that are used for the performance comparison of the presented algorithms are provided. Other emerging migration methods are also pointed out.

  17. Cooperative research at JAERI on the consequences of the Chernobyl accident. 3. Distribution and migration characteristics of long-lived radionuclides in the environment around the damaged Chernobyl reactor

    International Nuclear Information System (INIS)

    Amano, Hikaru

    2001-01-01

    The purpose of this study was to elucidate the actual long-term migration characteristics of radionuclides released and accumulated on the earth surface environment after the reactor accident. The objective areas were mainly in 30 km distant areas from the reactor. The study concerned the distribution of radionuclides on the ground surface, their physical and chemical forms, their migration characteristics, their migration from the ground to aqueous system like river, their physical and chemical forms in that system, their migration into vegetables, and their re-floating and concentration in air. The study involved those methods such as a newly developed liquid scintillation counting of 241 Pu for assessing 241 Am accumulation and the alpha-track method for detection of hot particles. Findings were: Hot particles of small diameters around several microns were still present; Depth distribution of radionuclides was dependent on the soil sort; Chemical forms of 90 Sr, 137 Cs and transuranium elements were different; Depth distribution in the soil depended on chemical forms; Annual change of radionuclides was evident in air; Migration coefficients to vegetables were determined; High molecular weight organic colloid was important in the migration to water system; Amounts of 137 Cs and transuranium elements depended on those of suspended matters in the river water and >90% 90 Sr were in soluble forms; Apparent partition ratios (soluble/suspended) of radionuclides in the river and lake were determined; Soluble transuranium elements were bound to humus materials in the river. (K.H.)

  18. NOTION, ELEMENTS AND EVALUATION OF HUMAN RESOURCES MANAGMENT IN SPORT

    OpenAIRE

    Milorad M. Drobac; Milica Radović

    2009-01-01

    Principal object of the author’s research in work is identification of notion, cru- cial elements and evaluation of human resources management in general and apart in sport. From the beginning of usage of term “human resources management”, we use foretoken “strategic” that has especially signified meaning. Strategic approach to the exploration of this problem points to the fact that human resources are from particularly significance for all forms of human organization (firms, associations, in...

  19. DESIGN AND EVALUATION OF INDIVIDUAL ELEMENTS OF THE INTERFACE FOR AN AGRICULTURAL MACHINE.

    Science.gov (United States)

    Rakhra, Aadesh K; Mann, Danny D

    2018-01-29

    If a user-centered approach is not used to design information displays, the quantity and quality of information presented to the user may not match the needs of the user, or it may exceed the capability of the human operator for processing and using that information. The result may be an excessive mental workload and reduced situation awareness of the operator, which can negatively affect the machine performance and operational outcomes. The increasing use of technology in agricultural machines may expose the human operator to excessive and undesirable information if the operator's information needs and information processing capabilities are ignored. In this study, a user-centered approach was used to design specific interface elements for an agricultural air seeder. Designs of the interface elements were evaluated in a laboratory environment by developing high-fidelity prototypes. Evaluations of the user interface elements yielded significant improvement in situation awareness (up to 11%; overall mean difference = 5.0 (4.8%), 95% CI (6.4728, 3.5939), p 0.0001). Mental workload was reduced by up to 19.7% (overall mean difference = -5.2 (-7.9%), n = 30, a = 0.05). Study participants rated the overall performance of the newly designed user-centered interface elements higher in comparison to the previous designs (overall mean difference = 27.3 (189.8%), 99% CI (35.150, 19.384), p 0.0001. Copyright© by the American Society of Agricultural Engineers.

  20. Bubble dynamics in microchannels: inertial and capillary migration forces

    Science.gov (United States)

    Rivero-Rodriguez, Javier; Scheid, Benoit

    2018-05-01

    This work focuses on the dynamics of a train of unconfined bubbles flowing in microchan- nels. We investigate the transverse position of a train of bubbles, its velocity and the associated pressure drop when flowing in a microchannel depending on the internal forces due to viscosity, inertia and capillarity. Despite the small scales of the system, inertia, referred to as inertial migration force, play a crucial role in determining the transverse equilibrium position of the bubbles. Beside inertia and viscosity, other effects may also affect the transverse migration of bubbles such as the Marangoni surface stresses and the surface deformability. We look at the influence of surfactants in the limit of infinite Marangoni effect which yields rigid bubble interface. The resulting migration force may balance external body forces if present such as buoyancy, Dean or magnetic ones. This balance not only determines the transverse position of the bubbles but, consequently, the surrounding flow structure, which can be determinant for any mass/heat transfer process involved. Finally, we look at the influence of the bubble deformation on the equilibrium position and compare it to the inertial migration force at the centred position, explaining the stable or unstable character of this position accordingly. A systematic study of the influence of the parameters - such as the bubble size, uniform body force, Reynolds and capillary numbers - has been carried out using numerical simulations based on the Finite Element Method, solving the full steady Navier-Stokes equations and its asymptotic counterpart for the limits of small Reynolds and/or capillary numbers.

  1. Clinical evaluation of a membrane-based voice-producing element for female laryngectomized patients

    NARCIS (Netherlands)

    Tack, Johannes W.; Qiu, Qingjun; Schutte, Harm K.; Kooijman, Piet G.C.; Meeuwis, Cees A.; van der Houwen, Eduard B.; Mahieu, Hans F.; Verkerke, Gijsbertus Jacob

    2008-01-01

    Background: A newly developed artificial voice source was clinically evaluated in laryngectomized women for voice quality improvements. The prosthesis was placed in a commercially available, tracheoesophageal shunt valve. - Methods: In 17 subjects, voice-producing element (VPE) prototypes were

  2. Evaluation of the 152Eu migration experiments using a combined reaction model

    International Nuclear Information System (INIS)

    Maloszewski, P.; Klotz, D.

    2001-01-01

    A transport and interaction model is applied to 152 Eu migration experiments which takes account simultaneously of fast (so-called local equilibrium) and slow (kinetic) exchange processes of the migrant between the aqueous and the solid phase [de

  3. The evaluation of multi-element personal dosemeters using the linear programming method

    International Nuclear Information System (INIS)

    Kragh, P.; Ambrosi, P.; Boehm, J.; Hilgers, G.

    1996-01-01

    Multi-element dosemeters are frequently used in individual monitoring. Each element can be regarded as an individual dosemeter with its own individual dose measurement value. In general, the individual dose values of one dosemeter vary according to the exposure conditions, i. e. the energy and angle of incidence of the radiation. The (final) dose measurement value of the personal dosemeter is calculated from the individual dose values by means of an evaluation algorithm. The best possible dose value, i.e. that of the smallest systematic (type B) uncertainty if the exposure conditions are changed in the dosemeter's rated range of use, is obtained by the method of linear programming. (author)

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

    NARCIS (Netherlands)

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

    2015-01-01

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

  5. Evaluated phase diagrams of binary metal-tellurium systems of the D-block transition elements

    International Nuclear Information System (INIS)

    Chattopadhyay, G.; Bharadwaj, S.R.

    1989-01-01

    The binary phase diagrams of metal-tellurium systems for twenty seven d-block transition elements have been critically evaluated. Complete phase diagrams are presented for the elements, chromium, manganese, iron, cobalt, nickel, copper, molybdenum, palladium, silver, lanthanum, platinum and gold, whereas, for scandium, titanium, vanadium, yttrium, zirconium, niobium, technitium, ruthenium, rhodium, hafnium, tantalum, tungsten , rhenium, osmium and iridium, the phase diagrams are incomplete and tentative. (author). 20 refs., 27 tabs., 27 figs

  6. Türkiye’de Kentten - Köye Göç Olgusu = The Phenomenon of the Urban - Rural Migration in Turkey

    Directory of Open Access Journals (Sweden)

    Ertuğrul GÜREŞÇİ

    2010-01-01

    Full Text Available In this study, causes and results of the urban-rural migration phenomena were evaluated. The relationship between urban-rural migration and rural-urban migration were determined taking them simultaneously. The significant result of study was that that the urban-rural migration stemmed from social changes taking part in Turkey.

  7. Testing the effects of basic numerical implementations of water migration on models of subduction dynamics

    Science.gov (United States)

    Quinquis, M. E. T.; Buiter, S. J. H.

    2014-06-01

    Subduction of oceanic lithosphere brings water into the Earth's upper mantle. Previous numerical studies have shown how slab dehydration and mantle hydration can impact the dynamics of a subduction system by allowing a more vigorous mantle flow and promoting localisation of deformation in the lithosphere and mantle. The depths at which dehydration reactions occur in the hydrated portions of the slab are well constrained in these models by thermodynamic calculations. However, computational models use different numerical schemes to simulate the migration of free water. We aim to show the influence of the numerical scheme of free water migration on the dynamics of the upper mantle and more specifically the mantle wedge. We investigate the following three simple migration schemes with a finite-element model: (1) element-wise vertical migration of free water, occurring independent of the flow of the solid phase; (2) an imposed vertical free water velocity; and (3) a Darcy velocity, where the free water velocity is a function of the pressure gradient caused by the difference in density between water and the surrounding rocks. In addition, the flow of the solid material field also moves the free water in the imposed vertical velocity and Darcy schemes. We first test the influence of the water migration scheme using a simple model that simulates the sinking of a cold, hydrated cylinder into a dry, warm mantle. We find that the free water migration scheme has only a limited impact on the water distribution after 1 Myr in these models. We next investigate slab dehydration and mantle hydration with a thermomechanical subduction model that includes brittle behaviour and viscous water-dependent creep flow laws. Our models demonstrate that the bound water distribution is not greatly influenced by the water migration scheme whereas the free water distribution is. We find that a bound water-dependent creep flow law results in a broader area of hydration in the mantle wedge, which

  8. Adsorption and migration of transplutonium elements in environmental systems

    Energy Technology Data Exchange (ETDEWEB)

    Balukova, V.D.; Kaymin, E.P.; Ushakov, S.I.

    Behavior of long decay-time transuranium and transplutonium elements in natural systems was addressed. The most dangerous among them are /sup 238/Np, /sup 241/ /sup 243/Am, /sup 244/ /sup 245/ /sup 246/Cm, and /sup 239/ /sup 240/ /sup 242/ /sup 244/Pu. Their transportation through natural deposits is tightly connected with ground water movements. The principal parameters determining behavior of these radionuclides in ground formations are coefficients of isotope distribution between various phases, adsorption capacities of component minerals, effective porosity, filtration coefficients of the liquid, etc. These data are presented in tabular and graphic forms. In carbonate-bicarbonate ground waters containing silicate minerals, the content of radionuclides could be quickly decreased by hydrolysis and formation of insoluble precipitates. 2 references, 3 figures.

  9. Young People's Migration and its Impact on Preserving Ethnic Features (on the Example of Kalmyks

    Directory of Open Access Journals (Sweden)

    L V Namruyeva

    2011-06-01

    Full Text Available The article views Labor migration as a means to solve unemployment problems in the republic. Migration shows not only the mobility of the population but it also reflects the life standards of the Kalmyk people in the past decade. Every year thousands of qualified specialists leave the region, which requires that they should comply with the new models of behavior and social standards that differ fundamentally from the mode of life in the agrarian Kalmyk republic. The megapolis changes the morals, values and ethnic features of labor migrants, imparting to them new elements of culture different from their ethnic nature. In the course of adaptation of Kalmyk-migrants to the conditions of the modern poly-ethnic city people tend to get estranged from their traditional ethno-environment, which eventually results in their loss of their native language and other elements of ethnic culture, unique traditions and customs gradually disappear, and the problem of preserving ethnicity in the Kalmyk diaspora arises.

  10. Migration of fluorochemical paper additives from food-contact paper into foods and food simulants.

    Science.gov (United States)

    Begley, T H; Hsu, W; Noonan, G; Diachenko, G

    2008-03-01

    Fluorochemical-treated paper was tested to determine the amount of migration that occurs into foods and food-simulating liquids and the characteristics of the migration. Migration characteristics of fluorochemicals from paper were examined in Miglyol, butter, water, vinegar, water-ethanol solutions, emulsions and pure oil containing small amounts of emulsifiers. Additionally, microwave popcorn and chocolate spread were used to investigate migration. Results indicate that fluorochemicals paper additives do migrate to food during actual package use. For example, we found that microwave popcorn contained 3.2 fluorochemical mg kg(-1) popcorn after popping and butter contained 0.1 mg kg(-1) after 40 days at 4 degrees C. Tests also indicate that common food-simulating liquids for migration testing and package material evaluation might not provide an accurate indication of the amount of fluorochemical that actually migrates to food. Tests show that oil containing small amounts of an emulsifier can significantly enhance migration of a fluorochemical from paper.

  11. 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.

  12. Efficient evaluation of the Coulomb force in the Gaussian and finite-element Coulomb method.

    Science.gov (United States)

    Kurashige, Yuki; Nakajima, Takahito; Sato, Takeshi; Hirao, Kimihiko

    2010-06-28

    We propose an efficient method for evaluating the Coulomb force in the Gaussian and finite-element Coulomb (GFC) method, which is a linear-scaling approach for evaluating the Coulomb matrix and energy in large molecular systems. The efficient evaluation of the analytical gradient in the GFC is not straightforward as well as the evaluation of the energy because the SCF procedure with the Coulomb matrix does not give a variational solution for the Coulomb energy. Thus, an efficient approximate method is alternatively proposed, in which the Coulomb potential is expanded in the Gaussian and finite-element auxiliary functions as done in the GFC. To minimize the error in the gradient not just in the energy, the derived functions of the original auxiliary functions of the GFC are used additionally for the evaluation of the Coulomb gradient. In fact, the use of the derived functions significantly improves the accuracy of this approach. Although these additional auxiliary functions enlarge the size of the discretized Poisson equation and thereby increase the computational cost, it maintains the near linear scaling as the GFC and does not affects the overall efficiency of the GFC approach.

  13. Evaluation of the Migration Capacity of Zn in the Soil–Plant System

    Science.gov (United States)

    Anisimov, V. S.; Anisimova, L. N.; Frigidova, L. M.; Dikarev, D. V.; Frigidov, R. A.; Korneev, Yu. N.; Sanzharov, A. I.; Arysheva, S. P.

    2018-04-01

    The mobility and migration capacity of Zn in the soil-plant system were studied in a series of pot experiments with barley as a test plant. The parameters of Zn accumulation depending on the metal concentrations in soils and soil solutions were estimated by soil and water culture methods. Experiments with barley in water culture were performed on a nutrient (soil) solution extracted from soddy-podzolic soil (Albic Retisol (Loamic, Ochric)) to which Zn2+ was added to reach working concentrations increasing from 0.07 to 430 μM. Different responses of barley plants to changes in the concentration of Zn in the studied soil were identified. Ranges of the corresponding concentrations in the soil and aboveground barley biomass were determined. Parameters of Zn accumulation by test plants were determined depending on the metal content in soddypodzolic soil and the soil solution. A new method was proposed for evaluating the buffer capacity of soils with respect to a heavy metal (Zn) using test plants (BCS(P)Zn). The method was used to evaluate the buffering capacity of loamy sandy soddy-podzolic soil. The considered methodological approach offers opportunities for using data obtained during the agroecological monitoring of agricultural lands with heavy metals (HMs), including the contents of exchangeable HMs and macroelements (C and Mg) in soils and concentrations of HMs and (Ca + Mg) in plants, in the calculation of the buffering capacity of the surveyed soils for HMs.

  14. 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....

  15. A generic model of contaminant migration from uranium tailings impoundments

    International Nuclear Information System (INIS)

    Shepherd, T.A.; Brown, S.E.

    1982-01-01

    This paper presents an analytical hydrogeochemical model based upon acid consumption-neutralization front movement. The development of contaminant plumes is discussed and distinct zones within these plumes are identified and characterized. The most important process influencing the rate and extent of contaminant migration at acid-leach uranium tailings impoundments is the neutralization of seepage water by soils along ground water flow paths. The chemical characteristics of the ground water is determined in order to identify and characterize zones within migrating plumes of tailings-derived water. It is concluded that the characterization of specific zones is useful in the interpretation of existing conditions, in the evaluation of future migration, and in the determination of appropriate models for the specific situation

  16. Estimation of percentage body fat by dual-energy x-ray absorptiometry: evaluation by in vivo human elemental composition

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zimian; Pierson, Richard N [Obesity Research Center, St Luke' s-Roosevelt Hospital, Columbia University, College of Physicians and Surgeons, New York, NY (United States); Heymsfield, Steven B [Clinical Research, Metabolism, Merck Research Laboratories, Rahway, NJ (United States); Chen Zhao [Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ (United States); Zhu Shankuan, E-mail: zw28@columbia.ed [Obesity and Body Composition Research Center, Zhejiang University, School of Public Health, Hangzhou (China)

    2010-05-07

    Dual-energy x-ray absorptiometry (DXA) is widely applied for estimating body fat. The percentage of body mass as fat (%fat) is predicted from a DXA-estimated R{sub ST} value defined as the ratio of soft tissue attenuation at two photon energies (e.g., 40 keV and 70 keV). Theoretically, the R{sub ST} concept depends on the mass of each major element in the human body. The DXA R{sub ST} values, however, have never been fully evaluated by measured human elemental composition. The present investigation evaluated the DXA R{sub ST} value by the total body mass of 11 major elements and the DXA %fat by the five-component (5C) model, respectively. Six elements (i.e. C, N, Na, P, Cl and Ca) were measured by in vivo neutron activation analysis, and potassium (i.e. K) by whole-body {sup 40}K counting in 27 healthy adults. Models were developed for predicting the total body mass of four additional elements (i.e. H, O, Mg and S). The elemental content of soft tissue, after correction for bone mineral elements, was used to predict the R{sub ST} values. The DXA R{sub ST} values were strongly associated with the R{sub ST} values predicted from elemental content (r = 0.976, P < 0.001), although there was a tendency for the elemental-predicted R{sub ST} to systematically exceed the DXA-measured R{sub ST} (mean {+-} SD, 1.389 {+-} 0.024 versus 1.341 {+-} 0.024). DXA-estimated %fat was strongly associated with 5C %fat (24.4 {+-} 12.0% versus 24.9 {+-} 11.1%, r = 0.983, P < 0.001). DXA R{sub ST} is evaluated by in vivo elemental composition, and the present study supports the underlying physical concept and accuracy of the DXA method for estimating %fat.

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

    Science.gov (United States)

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

    2017-07-01

    In lung inflammation, neutrophils are the first leukocytes migrating to an inflammatory site, eliminating pathogens by multiple mechanisms. The term "migration" describes several stages of neutrophil movement to reach the site of inflammation, of which the passage of the interstitium and basal membrane of the airway are necessary to reach the site of bronchial inflammation. Currently, several methods exist (e.g., Boyden Chamber, under-agarose assay, or microfluidic systems) to assess neutrophil mobility. However, these methods do not allow for parameterization on single cell level, that is, the individual neutrophil pathway analysis is still considered challenging. This study sought to develop a simplified yet flexible method to monitor and quantify neutrophil chemotaxis by utilizing commercially available tissue culture hardware, simple video microscopic equipment and highly standardized tracking. A chemotaxis 3D µ-slide (IBIDI) was used with different chemoattractants [interleukin-8 (IL-8), fMLP, and Leukotriene B4 (LTB 4 )] to attract neutrophils in different matrices like Fibronectin (FN) or human placental matrix. Migration was recorded for 60 min using phase contrast microscopy with an EVOS ® FL Cell Imaging System. The images were normalized and texture based image segmentation was used to generate neutrophil trajectories. Based on these spatio-temporal information a comprehensive parameter set is extracted from each time series describing the neutrophils motility, including velocity and directness and neutrophil chemotaxis. To characterize the latter one, a sector analysis was employed enabling the quantification of the neutrophils response to the chemoattractant. Using this hard- and software framework we were able to identify typical migration profiles of the chemoattractants IL-8, fMLP, and LTB 4 , the effect of the matrices FN versus HEM as well as the response to different medications (Prednisolone). Additionally, a comparison of four asthmatic and

  18. An evaluation of a translator for finite element data to resistor/capacitor data for the heat diffusion equation

    International Nuclear Information System (INIS)

    Manteufel, R.D.; Klein, D.E.; Yoshimura, H.R.

    1988-01-01

    This paper evaluates a translator for finite element data to resistor/capacitor data (FEM/RC) for the numerical solution of heat diffusion problems. The translator involves the derivation of thermal resistors and capacitors, implicit in the heat balance formulation of the finite difference method. It uses a finite element mesh, which consists of nodes and elements and is implicit in the Galerkin finite element method (GFEM). This hybrid translation method, FEM/RC, has been incorporated in Q/TRAN, a new thermal analysis computer code. This evaluation compares Q/TRAN, HEATING-6, and a research code employing GFEM on a purely mathematical, highly nonlinear steady-state conduction benchmark problem. The evaluation concludes that the FEM/RC technique has numerical characteristics that are consistent with comparable schemes for the benchmark problem. FEM/RC also accurately translates skewed meshes. Because FEM/RC generates resistors and capacitors, it appears to offer a more efficient method than the classical GFEM

  19. Migration abnormalities in cerebral malformations - evaluation of CT and MR examinations

    International Nuclear Information System (INIS)

    Uhlenbrock, D.; Sehlen, S.; Terwey, B.

    1991-01-01

    Twenty-eight patients with abnormalities of migration were examined with CT and MRI. Thirteen patients had heterotopia, ten patients had agyria/pachygyria, two with unilateral schizencephaly and three with hemimegalencephaly. MRI proved markedly superior because of its wider contrast range and its ability to obtain various imaging planes. The various conditions are described in detail. (orig.) [de

  20. Evaluation of trace element status of food articles

    International Nuclear Information System (INIS)

    Qureshi, I.H.; Ahmad, S.; Zaidi, S.J.; Mannan, A.; Waheed, S.; Fatima, I.; Arif, M.; Rahman, A.

    1996-01-01

    Food is the main source of major, minor and micro nutrients required for human beings. Food articles, due to environmental pollution may also contain some toxic elements which would adversely affect their health. In order to assess the adequacy and safety of human diet main food items were analyzed for the measurement of essential and toxic trace elements employing neutron activation analysis and atomic absorption spectrometry. The data so obtained will serve as baseline values and will be helpful to monitor the changes in the trace element contents of these items in future. The dietary intake of essential and toxic trace elements through these items was estimated and compared with the recommended values. This study indicates that the intake of essential elements except for co is fairly adequate and that of toxic elements in well well within the permissible limits. (author)

  1. Finite element modeling of stress corrosion cracking for electromagnetic nondestructive evaluations

    International Nuclear Information System (INIS)

    Wang, J.; Yusa, N.; Hashizume, H.

    2012-01-01

    This paper discusses appropriate numerical model for a stress corrosion crack (SCC) from the viewpoint of anisotropy of their conductivity. Two SCCs, which are introduced into a plate of type 316 stainless steel, are considered. Finite element simulations are carried out to evaluate the conductivity. In the simulations, the cracks are modeled as a region with a constant width on the basis of the destructive tests. The results show the conductivity on direction of width has large effect to the accuracy of numerical modeling of SCC, whereas the conductivities on direction of length and depth almost do not have remarkable effects. The results obtained by this study indicate that distribution of conductivity along the surface of a crack would be more important than the anisotropy in modeling SCCs in finite element simulations

  2. Calcium-containing scaffolds induce bone regeneration by regulating mesenchymal stem cell differentiation and migration

    Directory of Open Access Journals (Sweden)

    Rubén Aquino-Martínez

    2017-11-01

    Full Text Available Abstract Background Osteoinduction and subsequent bone formation rely on efficient mesenchymal stem cell (MSC recruitment. It is also known that migration is induced by gradients of growth factors and cytokines. Degradation of Ca2+-containing biomaterials mimics the bone remodeling compartment producing a localized calcium-rich osteoinductive microenvironment. The aim of our study was to determine the effect of calcium sulfate (CaSO4 on MSC migration. In addition, to evaluate the influence of CaSO4 on MSC differentiation and the potential molecular mechanisms involved. Methods A circular calvarial bone defect (5 mm diameter was created in the parietal bone of 35 Balb-C mice. We prepared and implanted a cell-free agarose/gelatin scaffold alone or in combination with different CaSO4 concentrations into the bone defects. After 7 weeks, we determined the new bone regenerated by micro-CT and histological analysis. In vitro, we evaluated the CaSO4 effects on MSC migration by both wound healing and agarose spot assays. Osteoblastic gene expression after BMP-2 and CaSO4 treatment was also evaluated by qPCR. Results CaSO4 increased MSC migration and bone formation in a concentration-dependent manner. Micro-CT analysis showed that the addition of CaSO4 significantly enhanced bone regeneration compared to the scaffold alone. The histological evaluation confirmed an increased number of endogenous cells recruited into the cell-free CaSO4-containing scaffolds. Furthermore, MSC migration in vitro and active AKT levels were attenuated when CaSO4 and BMP-2 were in combination. Addition of LY294002 and Wortmannin abrogated the CaSO4 effects on MSC migration. Conclusions Specific CaSO4 concentrations induce bone regeneration of calvarial defects in part by acting on the host’s undifferentiated MSCs and promoting their migration. Progenitor cell recruitment is followed by a gradual increment in osteoblast gene expression. Moreover, CaSO4 regulates BMP-2-induced

  3. Study of radionuclide migration in clay formations

    International Nuclear Information System (INIS)

    Antonioli, F.; Bocola, W.

    1985-01-01

    This paper reports the studies on the migration of Cs, Sr and I in clay formations, which are presently considered for the geological disposal of radioactive wastes. The distribution and diffusion coefficients were evaluated by means of experimental techniques and computer procedures, which are presented in this report. The natural clays tested in the laboratory experiments were sampled from the most representative italian basins and from the zone of Mol (Belgium). In addition tests were performed on monomineral clays artificially remade in edometer. The experimental results are in accordance with data found in the literature and show the existence of a good correlation between the observed migration properties and the granulometric and mineralogic characteristics of the natural clays

  4. Research on the Core Competitive Power Elements Evaluation System of Green Hotel

    Directory of Open Access Journals (Sweden)

    Hui Liang

    2013-12-01

    Full Text Available Green hotel is a new type of hospitality industry development model based on the concept of circular economy and sustainable development. This paper makes an analysis and evaluation of the elements of green hotel core competence, on this basis, constructs the Green Hotel core competitive evaluation index system.The construction of the system is conducive to understand the green hotel’s own competitive advantage objectively, and explore ways to enhance its core competitiveness, providing objective basis for sustainable development of China's Hotel industry.

  5. [Trans-uranium elements in food products (review)].

    Science.gov (United States)

    Vasilenko, I Ia

    1994-01-01

    The data of Russian and foreign authors concerning of level environmental contamination and migration of transuranic elements in food chains, metabolism and biological danger of nuclides entering in human body with foods are reviewed. A level of radionuclide load of population and doses of radiation are discussed and the danger is estimated. The doses of radiation from radionuclide ingestion are lower than level of allowed radiation safety standards.

  6. Migration into art

    DEFF Research Database (Denmark)

    Petersen, Anne Ring

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

  7. 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

  8. Understanding gendered aspects of migration aspiration and motives of university students by multivariate statistical methods

    Directory of Open Access Journals (Sweden)

    Đula Borozan

    2014-03-01

    Full Text Available The paper deals with the application of multivariate analysis of variance and logistic regression in measuring, explaining and evaluating (i gender differences in expressing migration aspirations, and (ii a gender effect on migration motivation of university students in Croatia. The results supported the thesis that migration is a complex gendering process that assumes subjective assessment of the whole set of interrelated motives. According to logistic regression, gender is a significant predictor of migration aspirations among the selected demographic and socio-economic variables. A multivariate analysis of variance showed that gender and migration aspirations in interaction matter when it comes to migration motives, particularly related to the perceived importance of social networks. Females, and especially those who aspire to migrate, assessed these motives as more important than males.

  9. Evaluation of Radionuclides Migration from RADON-Type Radioactive Waste Repository in Geosphere and Biosphere

    International Nuclear Information System (INIS)

    Grigaliuniene, D.; Poskas, P.

    2001-01-01

    Migration of radionuclides from hypothetical ISAM RADON-Type repository is analysed there. This is the first comprehensive analysis for such type repository. Generated four different system evolution and radionuclides migration scenarios cover a wide range of possible system states. Off-site scenarios as well as on-site scenarios consider radionuclide release from disposal facility and migration in geosphere and biosphere. Calculations are performed using computer code AMBER. According to the results, the highest dose is from two on-site scenarios (SCE1 erosion scenario and SCE3). The most important radionuclides in this case are 226 Ra with its decay products, 228 Ra, and 239 Pu. The doses from short-lived and mobile radionuclides arc insignificant for all on-site scenarios. The doses for the off-site scenarios are less than 0,1 mSv/y. Radon gases may cause the dose of about 1 mSv/y. The comparison of the results from this study and IAEA report for similar scenarios shows that the differences in most cases are less than one order of magnitude. (author)

  10. A novel method for the determination of migration of contaminants from food contact materials

    International Nuclear Information System (INIS)

    Thompson, D.; Parry, S.J.; Benzing, R.

    1996-01-01

    A neutron activation method has been developed for the analysis of high density polyethylene, low density polyethylene, polypropylene, polyethylene terephthalate and polystyrene food contact plastics. The method provides determination of over 50 elements at concentrations below 1 mg kg -1 . This technique has now been extended to study migration from food contact materials into standard food simulants (olive oil, acetic acid, ethanol and water). Samples of plastic are irradiated in a thermal neutron flux to procedure radionuclides of the elements present in the plastic. (author). 5 refs., 7 tabs

  11. Human migration patterns in Yemen and implications for reconstructing prehistoric population movements.

    Directory of Open Access Journals (Sweden)

    Aida T Miró-Herrans

    Full Text Available Population migration has played an important role in human evolutionary history and in the patterning of human genetic variation. A deeper and empirically-based understanding of human migration dynamics is needed in order to interpret genetic and archaeological evidence and to accurately reconstruct the prehistoric processes that comprise human evolutionary history. Current empirical estimates of migration include either short time frames (i.e. within one generation or partial knowledge about migration, such as proportion of migrants or distance of migration. An analysis of migration that includes both proportion of migrants and distance, and direction over multiple generations would better inform prehistoric reconstructions. To evaluate human migration, we use GPS coordinates from the place of residence of the Yemeni individuals sampled in our study, their birthplaces and their parents' and grandparents' birthplaces to calculate the proportion of migrants, as well as the distance and direction of migration events between each generation. We test for differences in these values between the generations and identify factors that influence the probability of migration. Our results show that the proportion and distance of migration between females and males is similar within generations. In contrast, the proportion and distance of migration is significantly lower in the grandparents' generation, most likely reflecting the decreasing effect of technology. Based on our results, we calculate the proportion of migration events (0.102 and mean and median distances of migration (96 km and 26 km for the grandparent's generation to represent early times in human evolution. These estimates can serve to set parameter values of demographic models in model-based methods of prehistoric reconstruction, such as approximate Bayesian computation. Our study provides the first empirically-based estimates of human migration over multiple generations in a developing

  12. Fundamental aspects of nuclear reactor fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Olander, D.R.

    1976-01-01

    The book presented is designed to function both as a text for first-year graduate courses in nuclear materials and as a reference for workers involved in the materials design and performance aspects of nuclear power plants. The contents are arranged under the following chapter headings: statistical thermodynamics, thermal properties of solids, crystal structures, cohesive energy of solids, chemical equilibrium, point defects in solids, diffusion in solids, dislocations and grain boundaries, equation of state of UO/sub 2/, fuel element thermal performance, fuel chemistry, behavior of solid fission products in oxide fuel elements, swelling due to fission gases, pore migration and fuel restructuring kinetics, fission gas release, mechanical properties of UO/sub 2/, radiation damage, radiation effects in metals, interaction of sodium and stainless steel, modeling of the structural behavior of fuel elements and assemblies. (DG)

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

    Science.gov (United States)

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

    2014-03-01

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

  14. 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

    ). The low to moderately saline (3-18 wt% NaCl) fluids with higher temperatures (200-550 deg. C), containing traces of O 2 , CH 4 and CO 2 are related to the reactors functioning and cooling with local silicification events. During the last compressional phase, the fluid paleo-circulations are mainly responsible of barren calcite crystallization (δ 13 C= 0 to -5 0/00 vs. PDB). (2) The Toarcian shales from experimental IPSN site in the Tournemire tunnel (Aveyron, France). Four mineral parageneses (calcite, calcite and framboidal pyrite, calcite and cubic pyrite, and calcite and barite) have been distinguished in fractures induced by compressional Pyrenean tectonic activities. The major- and trace-element contents, and the 87 Sr/ 86 Sr isotopic ratios (0.70847-0.70852) of the vein calcite are buffered by the surrounding shales, strongly suggesting short-distance migrations of the elements considered. Low uranium and high iron contents of the vein calcite suggest circulation of reducing fluids. However, an external origin for the carbonate fillings of the main fault, obtained with 87 Sr/ 86 Sr isotopic ratios (0.70841 and 0.70858), and of positive Eu anomalies in the REE patterns, cannot be excluded. This study shows that the competition between chemical aggressiveness of diagenetic fluids and buffering from surrounding rocks, with P-T conditions control determine or regulate the scale of element migration which has been important at Oklo and moderate at Tournemire. (author) [fr

  15. Regional Redistribution and Migration

    DEFF Research Database (Denmark)

    Manasse, Paolo; Schultz, Christian

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

  16. Climate services for society: origins, institutional arrangements, and design elements for an evaluation framework

    Science.gov (United States)

    Vaughan, Catherine; Dessai, Suraje

    2014-01-01

    Climate services involve the generation, provision, and contextualization of information and knowledge derived from climate research for decision making at all levels of society. These services are mainly targeted at informing adaptation to climate variability and change, widely recognized as an important challenge for sustainable development. This paper reviews the development of climate services, beginning with a historical overview, a short summary of improvements in climate information, and a description of the recent surge of interest in climate service development including, for example, the Global Framework for Climate Services, implemented by the World Meteorological Organization in October 2012. It also reviews institutional arrangements of selected emerging climate services across local, national, regional, and international scales. By synthesizing existing literature, the paper proposes four design elements of a climate services evaluation framework. These design elements include: problem identification and the decision-making context; the characteristics, tailoring, and dissemination of the climate information; the governance and structure of the service, including the process by which it is developed; and the socioeconomic value of the service. The design elements are intended to serve as a guide to organize future work regarding the evaluation of when and whether climate services are more or less successful. The paper concludes by identifying future research questions regarding the institutional arrangements that support climate services and nascent efforts to evaluate them. PMID:25798197

  17. Automated Tracking of Cell Migration with Rapid Data Analysis.

    Science.gov (United States)

    DuChez, Brian J

    2017-09-01

    Cell migration is essential for many biological processes including development, wound healing, and metastasis. However, studying cell migration often requires the time-consuming and labor-intensive task of manually tracking cells. To accelerate the task of obtaining coordinate positions of migrating cells, we have developed a graphical user interface (GUI) capable of automating the tracking of fluorescently labeled nuclei. This GUI provides an intuitive user interface that makes automated tracking accessible to researchers with no image-processing experience or familiarity with particle-tracking approaches. Using this GUI, users can interactively determine a minimum of four parameters to identify fluorescently labeled cells and automate acquisition of cell trajectories. Additional features allow for batch processing of numerous time-lapse images, curation of unwanted tracks, and subsequent statistical analysis of tracked cells. Statistical outputs allow users to evaluate migratory phenotypes, including cell speed, distance, displacement, and persistence, as well as measures of directional movement, such as forward migration index (FMI) and angular displacement. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  18. Modeling of the Migration of Glycerol Monoester Plasticizers in Highly Plasticized Poly(vinyl chloride)

    DEFF Research Database (Denmark)

    Lundsgaard, Rasmus; Kontogeorgis, Georgios; Kristiansen, Jørgen K.

    2009-01-01

    soybean oil (ESBO) with regard to their migration from three different types of poly(vinyl chloride) into isooctane at 20, 40, and 60 degrees C. Diffusion coefficients derived from the experimental migration data were evaluated against diffusion coefficients estimated from a model based solely...

  19. Reverse migration: Western European Muslim women’s flights to ISIL territory

    OpenAIRE

    DeSitter, Elizabeth A.

    2015-01-01

    Approved for public release; distribution is unlimited Since early 2014, the Islamic State of Iraq and the Levant (ISIL) has increasingly recruited Western Muslim men and women to its radical ideology. This thesis examines why Western European Muslim women—specifically from France and Great Britain—are voluntarily migrating to ISIL territory to support Islamic extremism. It evaluates women’s involvement in previous terrorist movements and proposes five potential motivations for migration: ...

  20. Piracicaba River Basin: evaluation of chemical elements in deep sediment profile by INAA

    Energy Technology Data Exchange (ETDEWEB)

    França, Elvis J. de; Santos, Robson A.; Santos, Katarine M. Barbosa; Silva, Gleyce K. A. [Centro Regional de Ciencias Nucleares do Nordeste (DIAMB/CRCN-NE/CNEN-PE), Recife, PE (Brazil). Div, de Monitoração Ambiental; Fernandes, Elisabete A. de Nadai; Rodrigues, Vanessa S.; Cavalca, Isabel P.O., E-mail: ejfranca@cnen.gov.br, E-mail: lis@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)

    2017-07-01

    Many hydrographic basins have been impacted by anthropogenic sources, the Piracicaba River Basin of the State of São Paulo, is one of that. The total concentrations of chemical elements in deep sediments of basin may be indicate those available in ecosystem. Therefore, in this research concentration of chemical elements on deep sediment profile sampled of Piracicaba River Basin was determined by k0-Instrumental Neutron Activation Analysis. After collecting the 60 cm depth profile, samples were obtained by sectioning the sediment profile in 5 cm layers, totalizing 12 samples. Analytical portions were transferred to polyethylene vials for neutron irradiation at the Nuclear Research Reactor IEA-R1 from the Instituto de Pesquisas Energéticas e Nucleares IPEN/CNEN. After waiting for radiation safe levels, irradiated samples were transported to the Radioisotopes Laboratory from the Centro de Energia Nuclear na Agricultura CENA/USP. High Resolution Gamma-Ray Spectrometry using HPGe detectors was applied to measure the induced radioactivity. The chemical element mass fractions and their respective expanded analytical uncertainties (95% confidence level) were determined by k0-INAA using the in-house software Quantu. Geological reference materials were analyzed with samples to evaluate the quality of the analytical procedure. Results indicated the presence of enriched surface sediments (0-10 cm depth) for As, Ba, Ca, Co, Cs, Fe, Sb, Sc, Sr, Yb and Zn, despite no alteration was observed for Eu, Ta and Tb. Therefore, the evaluation of deep sediment profile afford the chemical element dynamics for the Piracicaba Basin. (author)

  1. Piracicaba River Basin: evaluation of chemical elements in deep sediment profile by INAA

    International Nuclear Information System (INIS)

    França, Elvis J. de; Santos, Robson A.; Santos, Katarine M. Barbosa; Silva, Gleyce K. A.

    2017-01-01

    Many hydrographic basins have been impacted by anthropogenic sources, the Piracicaba River Basin of the State of São Paulo, is one of that. The total concentrations of chemical elements in deep sediments of basin may be indicate those available in ecosystem. Therefore, in this research concentration of chemical elements on deep sediment profile sampled of Piracicaba River Basin was determined by k0-Instrumental Neutron Activation Analysis. After collecting the 60 cm depth profile, samples were obtained by sectioning the sediment profile in 5 cm layers, totalizing 12 samples. Analytical portions were transferred to polyethylene vials for neutron irradiation at the Nuclear Research Reactor IEA-R1 from the Instituto de Pesquisas Energéticas e Nucleares IPEN/CNEN. After waiting for radiation safe levels, irradiated samples were transported to the Radioisotopes Laboratory from the Centro de Energia Nuclear na Agricultura CENA/USP. High Resolution Gamma-Ray Spectrometry using HPGe detectors was applied to measure the induced radioactivity. The chemical element mass fractions and their respective expanded analytical uncertainties (95% confidence level) were determined by k0-INAA using the in-house software Quantu. Geological reference materials were analyzed with samples to evaluate the quality of the analytical procedure. Results indicated the presence of enriched surface sediments (0-10 cm depth) for As, Ba, Ca, Co, Cs, Fe, Sb, Sc, Sr, Yb and Zn, despite no alteration was observed for Eu, Ta and Tb. Therefore, the evaluation of deep sediment profile afford the chemical element dynamics for the Piracicaba Basin. (author)

  2. 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.

  3. Illegal Migration and Human Smuggling in Central and Eastern Europe

    Directory of Open Access Journals (Sweden)

    Peter Futo

    2005-06-01

    Full Text Available The analytical and statistical services of border management organizations in Central and Eastern European countries have registered and accumulated a vast body of knowledge on the demographics and mechanisms of illegal migration over the last one-and-a-half decade. This paper attempts to tap this resource by summarising the results of a yearly survey among border guards of 17 countries. A set of quantitative indicators of illegal migration is developed, presented and interpreted, based on the answers of the border services to a series of quantitative and qualitative questions. This empirical material is used to evaluate the dynamics and pattern of illegal migration in Central and Eastern Europe on the one hand, and to examine the development of border management strategies on the other. The impacts of legal and institutional reforms are investigated in light of the temporal and spatial variations of border apprehension statistics. The interdependence of the two processes is reviewed from the point of view of national border management authorities, perhaps the most authoritative source of information on the issue. The results of the authors’ annual survey indicate that the progressive development of migration control mechanisms at national and international levels seems to have a significant impact on irregular migration flows as most indicators of illegal migration have significantly decreased after the turn of the century. At the same time, the geographical distribution of illegal migration flows in Central and Eastern European countries has become more complex over the years.

  4. Estimation of percentage body fat by dual-energy x-ray absorptiometry: evaluation by in vivo human elemental composition

    International Nuclear Information System (INIS)

    Wang Zimian; Pierson, Richard N; Heymsfield, Steven B; Chen Zhao; Zhu Shankuan

    2010-01-01

    Dual-energy x-ray absorptiometry (DXA) is widely applied for estimating body fat. The percentage of body mass as fat (%fat) is predicted from a DXA-estimated R ST value defined as the ratio of soft tissue attenuation at two photon energies (e.g., 40 keV and 70 keV). Theoretically, the R ST concept depends on the mass of each major element in the human body. The DXA R ST values, however, have never been fully evaluated by measured human elemental composition. The present investigation evaluated the DXA R ST value by the total body mass of 11 major elements and the DXA %fat by the five-component (5C) model, respectively. Six elements (i.e. C, N, Na, P, Cl and Ca) were measured by in vivo neutron activation analysis, and potassium (i.e. K) by whole-body 40 K counting in 27 healthy adults. Models were developed for predicting the total body mass of four additional elements (i.e. H, O, Mg and S). The elemental content of soft tissue, after correction for bone mineral elements, was used to predict the R ST values. The DXA R ST values were strongly associated with the R ST values predicted from elemental content (r = 0.976, P ST to systematically exceed the DXA-measured R ST (mean ± SD, 1.389 ± 0.024 versus 1.341 ± 0.024). DXA-estimated %fat was strongly associated with 5C %fat (24.4 ± 12.0% versus 24.9 ± 11.1%, r = 0.983, P ST is evaluated by in vivo elemental composition, and the present study supports the underlying physical concept and accuracy of the DXA method for estimating %fat.

  5. Sorption and Migration Mechanisms of 237 Np through Sandy Soil

    International Nuclear Information System (INIS)

    Chantaraprachoom, Nanthavan; Tanaka, Tadao

    2003-06-01

    In order to evaluate migration behavior of radioactive nuclides in the disposal of low-level radioactive waste into a shallow land burial, the sorption characteristic and migration behavior of 237 Np through sandy soil was studied. Two experimental methods were performed by using batch and column systems. The distribution coefficients (K d ) obtained from the adsorption and desorption process are rather small about 16 and 21 cm 3 /g respectively. Size distribution of 237 Np species in the influent solution was measured by ultra-filtration technique. Migration mechanism of 237 Np was studied by column experiments. The experimental condition was the influence of volume of eluting solution; 100, 300, 500, 1000 and 2000 ml respectively. The result from five column experiments confirm that the sorption characteristics of 237 Np are mainly controlled by a reversible ion-exchange reaction and the migration of 237 Np in the sandy soil can be estimated by using the K d concept

  6. Migration of perfluoroalkyl acids from food packaging to food simulants.

    Science.gov (United States)

    Xu, Y; Noonan, G O; Begley, T H

    2013-01-01

    A broad range of fluorochemicals is used to impart oil and water barrier properties to paper and paperboard food packaging. Many of the fluorochemicals are applied to paper and paperboard as complex mixtures containing reaction products and by-products and unreacted starting materials. This work primarily focussed on the determination of seven perfluorocarboxylic acids (PFCAs) in two commercially available food contact papers: a di-perfluoro-alkyloxy-amino-acid and a perfluoroalkyl phosphate surfactant. In addition, the migration of the PFCAs into five food simulants from two commercial packages was evaluated. All seven PFCAs were detected in the range of 700-2220 µg kg⁻¹ of paper, while three perfluoroalkyl sulphonates were under the LOD. Results from migration tests showed that migration depends on paper characteristics, time and food simulant. The percentage of migration after 10 days at 40°C ranged from 4.8% to 100% for the two papers and different food simulants.

  7. 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.

  8. 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....

  9. A PDMS Device Coupled with Culture Dish for In Vitro Cell Migration Assay.

    Science.gov (United States)

    Lv, Xiaoqing; Geng, Zhaoxin; Fan, Zhiyuan; Wang, Shicai; Pei, WeiHua; Chen, Hongda

    2018-04-30

    Cell migration and invasion are important factors during tumor progression and metastasis. Wound-healing assay and the Boyden chamber assay are efficient tools to investigate tumor development because both of them could be applied to measure cell migration rate. Therefore, a simple and integrated polydimethylsiloxane (PDMS) device was developed for cell migration assay, which could perform quantitative evaluation of cell migration behaviors, especially for the wound-healing assay. The integrated device was composed of three units, which included cell culture dish, PDMS chamber, and wound generation mold. The PDMS chamber was integrated with cell culture chamber and could perform six experiments under different conditions of stimuli simultaneously. To verify the function of this device, it was utilized to explore the tumor cell migration behaviors under different concentrations of fetal bovine serum (FBS) and transforming growth factor (TGF-β) at different time points. This device has the unique capability to create the "wound" area in parallel during cell migration assay and provides a simple and efficient platform for investigating cell migration assay in biomedical application.

  10. The next waves: migration theory for a changing world.

    Science.gov (United States)

    Zolberg, A R

    1989-01-01

    In the last quarter of a century, migration theory has undergone fundamental change, moving from the classic "individual relocation" genre initiated by Ravenstein a century ago, to a variety of new approaches which nevertheless share important elements: they tend to be historical, structural, globalist, and critical. Historicization implies a constant modification of theoretical concerns and emphases in the light of changing social realities, and a commitment to a critical approach entails a view of research as 1 element in a broader project concerned with the elucidation of social and political conditions. The article uses elements from 2 major theoretical traditions - a modified world-systems approach and state theory - to project current trends. Global inequality is considered as a structural given. The article then reviews major topics, including the persistence of restrictive immigration policies as barriers to movement, changing patterns of exploitation of foreign labor, liberalization of exit from the socialist world, and the refugee crisis in the developing world. It concludes with a brief consideration of the normative implications of these trends.

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

    Science.gov (United States)

    Lawson, V

    1999-01-01

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

  12. Contaminant transport, revegetation, and trace element studies at inactive uranium mill tailings piles

    International Nuclear Information System (INIS)

    Dreesen, D.R.; Marple, M.L.; Kelley, N.E.

    1978-01-01

    The stabilization of inactive uranium mill tailings piles is presently under study. These studies have included investigations of stabilizing tailings by attempting to establish native vegetation without applying irrigation. Examination of processes which transport tailings or associated contaminants into the environment has been undertaken to better understand the containment provided by various stabilization methods. The uptake of toxic trace elements and radionuclides by vegetation has been examined as a mechanism of contaminant transport. The source terms of 222 Rn from inactive piles have been determined as well as the attenuation of radon flux provided by shallow soil covers. The possibility of shallow ground water contamination around an inactive pile has been examined to determine the significance of ground water transport as a mode of contaminant migration. The rationale in support of trace element studies related to uranium milling activities is presented including the enrichment, migration, and toxicities of trace elements often associated with uranium deposits. Some concepts for the stabilization of inactive piles are presented to extrapolate from research findings to practical applications. 25 references, 8 tables

  13. Hydraulic and hydrodynamic tests for design evaluation of research reactors fuel elements

    International Nuclear Information System (INIS)

    Kulichevsky, R.; Martin Ghiselli, A.; Fiori, J.; Yedros, P.

    2002-01-01

    During the design steps of research reactors fuel elements some tests are usually necessary to verify its design, i.e.: its hydraulic characteristics, dynamical response and structural integrity. The hydraulic tests are developed in order to know the pressure drops characteristics of different parts or elements of the prototype and of the whole fuel element. Also, some tests are carried out to obtain the velocity distribution of the coolant water across different prototype's sections. The hydrodynamic tests scopes are the assessment of the dynamical characteristics of the fuel elements and their components and its dynamical response considering the forces generated by the coolant flowing water at different flow rate conditions. Endurance tests are also necessary to qualify the structural design of the FE prototypes and their corresponding clamp tools, verifying the whole system structural integrity and wear processes influences. To carry out these tests a special test facility is needed to obtain a proper representation of the hydraulic and geometric boundary conditions of the fuel element. In some cases changes on the fuel element prototype or dummy are necessary to assure that the data results are representative of the case under study. Different kind of sensors are mounted on the test section and also on the fuel element itself when necessary. Some examples of the instrumentation used are strain gauges, displacement transducers, absolute and differential pressure transducers, pitot tubes, etc. The obtained data are, for example, plates' vibration amplitudes and frequencies, whole bundle displacement characterization, pressure drops and flow velocity measurements. The Experimental Low Pressure Loop is a hydraulic loop located at CNEA's Constituyentes Atomic Center and is the test facility where different kind of tests are performed in order to support and evaluate the design of research reactor fuel elements. A brief description of the facility, and examples of

  14. Migration and speciation of heavy metal in salinized mine tailings affected by iron mining.

    Science.gov (United States)

    Zhang, Xu; Yang, Huanhuan; Cui, Zhaojie

    2017-10-01

    The negative effects of heavy metals have aroused much attention due to their high toxicity to human beings. Migration and transformation trend of heavy metals have a close relationship with soil safety. Researching on migration and transformation of heavy metals in tailings can provide a reliable basis for pollution management and ecosystem restoration. Heavy metal speciation plays an important role in risk assessment. We chose Anshan tailings for our study, including field investigations and laboratory research. Four typical heavy metal elements of mine tailings {Fe (373.89 g/kg), Mn (2,303.80 mg/kg), Pb (40.99 mg/kg) and Cr (199.92 mg/kg)} were studied via Tessier test in vertical and horizontal direction. The main speciation of heavy metals in Anshan tailings was the residual. However, heavy metals have a strong ability for migration and transformation in vertical and horizontal directions. Its tendency to change from stable to unstable speciation results in increasing bioavailability and potential bioavailability. Fe, Mn, Pb and Cr showed different ability in the migration and transformation process (Mn > Pb > Fe > Cr) depending on the characteristics of heavy metals and physicochemical properties of the environment.

  15. 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...

  16. NO-dependent proliferation and migration induced by Vitamin D in HUVEC.

    Science.gov (United States)

    Pittarella, Pamela; Squarzanti, Diletta F; Molinari, Claudio; Invernizzi, Marco; Uberti, Francesca; Renò, Filippo

    2015-05-01

    Recently, Vitamin D (Vit. D) has gained importance in cellular functions of a wide range of extraskeletal organs and target tissues, other than bone. In particular, Vit. D has displayed important beneficial effects in the cardiovascular system. Although little is known about the mechanism by which this response is exerted, a Vit. D-induced eNOS-dependent nitric oxide (NO) production in endothelial cells (EC) has been reported. The aim of this study was to evaluate whether Vit. D administration could affect human EC proliferation and/or migration through NO production. For this purpose, HUVEC (human umbilical vein endothelial cells) were used to evaluate Vit. D effects on cell proliferation and migration in a 3D matrix. Experiments were also performed in the presence of the specific VDR ligand ZK159222 and eNOS inhibitor L-NAME. This study demonstrated that Vit. D can promote both HUVEC proliferation and migration in a 3D matrix. These effects were NO dependent, since HUVEC proliferation and migration were abrogated along with Vit. D induced MMP-2 expression by inhibiting eNOS activity by L-NAME. These findings support the role of Vit. D in the angiogenic process, suggesting new applications for Vit. D in tissue repair and wound healing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. 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 ...

  18. Migration and the Transformation of Multiethnic Population Structure in the Kaliningrad Region of the Post-Soviet Era

    Directory of Open Access Journals (Sweden)

    Zimovina E. P.

    2014-06-01

    Full Text Available This paper analyses the migration processes and their influence on the transformation of multiethnic population structure in the Kaliningrad region. The author uses official statistics (current statistics and census data, as well as interviews with the representatives of ethnic cultural associations as information sources. Special attention is paid to the migration features associated with different ethnic groups. The author identifies major reasons behind the incoming and outgoing movement of population. In the post-Soviet period the Kaliningrad region has experienced positive net migration. This active migration into the region has contributed to the development of “migration networks” and established a new basis for further population increase through migration. The article describes changes in the regional multiethnic population structure and identifies key factors behind them. It is concluded that migration has played the decisive role in the process of multiethnic population structure transformation in the Kaliningrad region in the post-Soviet period. The author views migration as a serious test for both the migrants and the receiving society. On the one hand, migrants have to adapt to a different national, cultural, and linguistic environment and look for the ways of successful integration into the receiving society. On the other hand, the receiving society also faces a serious transformation as a result of the changing population size and structure, the emergence of new elements in culture, rules of behaviour, and the development of new attitudes.

  19. Experiences from the Architectural Migration of a Joint Replacement Surgery Information System

    Directory of Open Access Journals (Sweden)

    Samuli Niiranen

    2008-01-01

    Full Text Available The goal of this study is to present the experiences gathered from the migration of an existing and deployed joint replacement surgery information system from a classical 2-tier architecture to a 4-tier architecture. These include discussion on the motivation for the migration and on the technical benefits of the chosen technical migration path and an evaluation of user experiences. The results from the analysis of clinical end-user and administrator experiences show an increase in the perceived performance and maintainability of the system and a high level of acceptance for the new system version.

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

    International Nuclear Information System (INIS)

    Smith, C.L.

    1976-11-01

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

  1. 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...

  2. Diversity and MIMO Performance Evaluation of Common Phase Center Multi Element Antenna Systems

    Directory of Open Access Journals (Sweden)

    V. Papamichael

    2008-06-01

    Full Text Available The diversity and Multiple Input Multiple Output (MIMO performance provided by common phase center multi element antenna (CPCMEA systems is evaluated using two practical methods which make use of the realized active element antenna patterns. These patterns include both the impact of the mutual coupling and the mismatch power loss at antenna ports. As a case study, two and four printed Inverted F Antenna (IFA systems are evaluated by means of Effective Diversity Gain (EDG and Capacity (C. EDG is measured in terms of the signal-to-noise ratio (SNR enhancement at a specific outage probability and in terms of the SNR reduction for achieving a desired average bit error rate (BER. The concept of receive antenna selection in MIMO systems is also investigated and the simulation results show a 43% improvement in the 1% outage C of a reconfigurable 2x2 MIMO system over a fixed 2x2 one.

  3. 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

  4. Effects of sorption behaviour on contaminant migration

    International Nuclear Information System (INIS)

    Melnyk, T.W.

    1985-11-01

    The effects of sorption behaviour on contaminant migration in groundwater systems are varied. Retardation of migration and dispersive effects can vary widely and contaminant concentration profiles can take a number of different shapes. This report examines the nature of some of these effects, especially those due to sorption behaviours that are dependent on the concentration of the contaminant in the groundwater. The effects are calculated using, in most cases, analytical solutions to the chemical equations imbedded in a simple reaction-cell or box-model transport algorithm. The hydrogeological parameters are held constant, and radioactive decay and hydrodynamic dispersion are excluded. A general discussion of the role of sorption equations in transport modelling is followed by presentation of migration results for a number of models of sorption behaviour varying from linear isotherms, Langmuir, Freundlich and ion-exchange isotherms, to precipitation reactions and multiple-site sorption reactions. The results are compared and general conclusions are drawn about the various migration behaviours calculated. The conclusions are that equilibrium sorption of trace contaminants can be modelled with linear isotherms (constant distribution coefficients or constant retardation factors) but the evaluation and extrapolation of the distribution coefficient are not easy. Nonlinear isotherms lead to unsymmetrical migration fronts. A comparison of Freundlich and linear isotherms is made. Sorption/desorption kinetic factors can be significant on the time scale of laboratory experiments and can cause large dispersive effects. Slow but important reactions can be missed altogether. Precipitation or mineralization behaviour cannot be modelled with constant distribution coefficients. Also, mineralization reactions can be kinetically slow even on the geological time scale. 89 refs

  5. Hydrology of the solid waste burial ground as related to potential migration of radionuclides, Idaho National Engineering Laboratory

    Science.gov (United States)

    Barraclough, Jack T.; Robertson, J.B.; Janzer, V.J.; Saindon, L.G.

    1976-01-01

    A study was made (1970-1974) to evaluate the geohydrologic and geochemical controls on subsurface migration of radionuclides from pits and trenches in the Idaho National Engineering Laboratory (INEL) solid waste burial ground and to determine the existence and extent of radionuclide migration from the burial ground. A total of about 1,700 sediment, rock, and water samples were collected from 10 observation wells drilled in and near the burial ground of Idaho National Engineering Laboratory, formerly the National Reactor Testing Station (NRTS). Within the burial ground area, the subsurface rocks are composed principally of basalt. Wind- and water-deposited sediments occur at the surface and in beds between the thicker basalt zones. Two principal sediment beds occur at about 110 feet and 240 feet below the land surface. The average thickness of the surficial sedimentary layer is about 15 feet while that of the two principal subsurface layers is 13 and 14 feet, respectively. The water table in the aquifer beneath the burial ground is at a depth of about 580 feet. Fission, activation, and transuranic elements were detected in some of the samples from the 110- and 240-foot sedimentary layers. (Woodard-USGS)

  6. 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.

  7. 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...

  8. Internal migration of physicians who graduated in Brazil between 1980 and 2014.

    Science.gov (United States)

    Scheffer, Mario Cesar; Cassenote, Alex Jones Flores; Guilloux, Aline Gil Alves; Dal Poz, Mario Roberto

    2018-05-02

    The internal migration of physicians from one place to another in the same country can unbalance the supply and distribution of these professionals in national health systems. In addition to economic, social and demographic issues, there are individual and professional factors associated with a physician's decision to migrate. In Brazil, there is an ongoing debate as to whether opening medicine programmes in the interior of the country can induce physicians to stay in these locations. This article examines the migration of physicians in Brazil based on the location of the medical schools from which they graduated. A cross-sectional design based on secondary data of 275,801 physicians registered in the Regional Councils of Medicine (Conselhos Regionais de Medicina-CRMs) who graduated between 1980 and 2014. The evaluated outcome was migration, which was defined as moving away from the state where they completed the medicine programme to another state where they currently work or live. 57.3% of the physicians in the study migrated. The probability of migration ratio was greater in small grouped municipalities and lower in state capitals. 93.4% of the physicians who trained in schools located in cities with less than 100,000 inhabitants migrated. Fewer women (54.2%) migrated than men (60.0%). More than half of the physicians who graduated between 1980 and 2014 are in federative units different from the unit in which they graduated. Individual factors, such as age, gender, time of graduation and specialty, vary between the physicians who did or did not migrate. The probability of migration ratio was greater in small municipalities of the Southeast region and strong in the states of Tocantins, Acre and Santa Catarina. New studies are recommended to deepen understanding of the factors related to the internal migration and non-migration of physicians to improve human resource for health policies.

  9. Hydrogeological Properties of Geological Elements in Geological Model around KURT

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kyung Woo; Kim, Kyung Soo; Koh, Yong Kwon; Choi, Jong Won [Korea Atomic Energy Institue, Daejeon (Korea, Republic of)

    2012-09-15

    To develop site characterization technologies for a radioactive waste disposal research in KAERI, the geological and hydrogeological investigations have been carried out since 1997. In 2006, the KURT (KAERI Underground Research Tunnel) was constructed to study a solute migration, a microbiology and an engineered barrier system as well as deeply to understand geological environments in in-situ condition. This study is performed as one of the site characterization works around KURT. Several investigations such as a lineament analysis, a borehole/tunnel survey, a geophyscial survey and logging in borehole, were used to construct the geological model. As a result, the geological model is constructed, which includes the lithological model and geo-structural model in this study. Moreover, from the results of the in-situ hydraulic tests, the hydrogeological properties of elements in geological model were evaluated.

  10. Hydrogeological Properties of Geological Elements in Geological Model around KURT

    International Nuclear Information System (INIS)

    Park, Kyung Woo; Kim, Kyung Soo; Koh, Yong Kwon; Choi, Jong Won

    2012-01-01

    To develop site characterization technologies for a radioactive waste disposal research in KAERI, the geological and hydrogeological investigations have been carried out since 1997. In 2006, the KURT (KAERI Underground Research Tunnel) was constructed to study a solute migration, a microbiology and an engineered barrier system as well as deeply to understand geological environments in in-situ condition. This study is performed as one of the site characterization works around KURT. Several investigations such as a lineament analysis, a borehole/tunnel survey, a geophyscial survey and logging in borehole, were used to construct the geological model. As a result, the geological model is constructed, which includes the lithological model and geo-structural model in this study. Moreover, from the results of the in-situ hydraulic tests, the hydrogeological properties of elements in geological model were evaluated.

  11. Survival of migrating salmon smolts in large rivers with and without dams.

    Directory of Open Access Journals (Sweden)

    David W Welch

    2008-10-01

    Full Text Available The mortality of salmon smolts during their migration out of freshwater and into the ocean has been difficult to measure. In the Columbia River, which has an extensive network of hydroelectric dams, the decline in abundance of adult salmon returning from the ocean since the late 1970s has been ascribed in large measure to the presence of the dams, although the completion of the hydropower system occurred at the same time as large-scale shifts in ocean climate, as measured by climate indices such as the Pacific Decadal Oscillation. We measured the survival of salmon smolts during their migration to sea using elements of the large-scale acoustic telemetry system, the Pacific Ocean Shelf Tracking (POST array. Survival measurements using acoustic tags were comparable to those obtained independently using the Passive Integrated Transponder (PIT tag system, which is operational at Columbia and Snake River dams. Because the technology underlying the POST array works in both freshwater and the ocean, it is therefore possible to extend the measurement of survival to large rivers lacking dams, such as the Fraser, and to also extend the measurement of survival to the lower Columbia River and estuary, where there are no dams. Of particular note, survival during the downstream migration of at least some endangered Columbia and Snake River Chinook and steelhead stocks appears to be as high or higher than that of the same species migrating out of the Fraser River in Canada, which lacks dams. Equally surprising, smolt survival during migration through the hydrosystem, when scaled by either the time or distance migrated, is higher than in the lower Columbia River and estuary where dams are absent. Our results raise important questions regarding the factors that are preventing the recovery of salmon stocks in the Columbia and the future health of stocks in the Fraser River.

  12. Biomechanical Evaluations of Hip Fracture Using Finite Element Model that Models Individual Differences of Femur

    OpenAIRE

    田中, 英一; TANAKA, Eiichi; 山本, 創太; YAMAMOTO, Sota; 坂本, 誠二; SAKAMOTO, Seiji; 中西, 孝文; NAKANISHI, Takafumi; 原田, 敦; HARADA, Atsushi; 水野, 雅士; MIZUNO, Masashi

    2004-01-01

    This paper is concerned with an individual finite element modeling system for femur and biomechanical evaluations of the influences of loading conditions, bone shape and bone density on risks of hip fracture. Firstly, a method to construct an individual finite element model by morphological parameters that represent femoral shapes was developed. Using the models with different shapes constructed by this method, the effects of fall direction, posture of upper body, femur shape and bone density...

  13. Quantitative multi-waves migration in elastic anisotropic media; Migration quantitative multi-ondes en milieu elastique anisotrope

    Energy Technology Data Exchange (ETDEWEB)

    Borgne, H.

    2004-12-01

    modelling of waves propagation in anisotropic media. With the approximations of ray theory, 1 develop an expression of the geometrical spreading, the amplitude, and their reciprocity relations. I set up imaging formulas in order to reconstruct the reflection coefficients of the subsurface in elastic anisotropic media. In a first time, 1 salve the direct problem, by expressing the integral relation between the scattered wave field recorded by the receivers and the subsurface reflection coefficients. In a second time, 1 apply an elastic anisotropic quantitative migration method, based on the properties of the inverse Radon transforms (Beylkin's approach), in order to express the reflection coefficient in 2D, 2.5D and 3D media. 1 implemented these formulas in a new preserved amplitude migration algorithm, where the images are sorted by angle classes. At last, 1 apply these theoretical results to synthetic and real datasets. 1 show that migration is able to reconstruct the correct A V A behavior of anisotropic reflection coefficients if hath. modifications are achieved. Then, 1 degrade the process, by keeping an anisotropic ray tracing but using the classical isotropic imaging formula. F'or this commonly used configuration, 1 evaluate the error that can be expected in the A V A response of the migrated reflection coefficient. Methodological applications show the sensibility of the migration results to the velocity model smoothing and to an error on the anisotropic axis. (author)

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

    Directory of Open Access Journals (Sweden)

    Richelle L. Winkler

    2015-05-01

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

  15. Evaluating rare earth element availability: a case with revolutionary demand from clean technologies.

    Science.gov (United States)

    Alonso, Elisa; Sherman, Andrew M; Wallington, Timothy J; Everson, Mark P; Field, Frank R; Roth, Richard; Kirchain, Randolph E

    2012-03-20

    The future availability of rare earth elements (REEs) is of concern due to monopolistic supply conditions, environmentally unsustainable mining practices, and rapid demand growth. We present an evaluation of potential future demand scenarios for REEs with a focus on the issue of comining. Many assumptions were made to simplify the analysis, but the scenarios identify some key variables that could affect future rare earth markets and market behavior. Increased use of wind energy and electric vehicles are key elements of a more sustainable future. However, since present technologies for electric vehicles and wind turbines rely heavily on dysprosium (Dy) and neodymium (Nd), in rare-earth magnets, future adoption of these technologies may result in large and disproportionate increases in the demand for these two elements. For this study, upper and lower bound usage projections for REE in these applications were developed to evaluate the state of future REE supply availability. In the absence of efficient reuse and recycling or the development of technologies which use lower amounts of Dy and Nd, following a path consistent with stabilization of atmospheric CO(2) at 450 ppm may lead to an increase of more than 700% and 2600% for Nd and Dy, respectively, over the next 25 years if the present REE needs in automotive and wind applications are representative of future needs.

  16. 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)

  17. Postirradiation examinations of the BG-9 element

    International Nuclear Information System (INIS)

    Strain, R.V.; Renfro, C.W.; Neimark, L.A.

    1976-10-01

    Postirradiation examinations were performed on the GB-9 element irradiated in the Oak Ridge Reactor. This vented fuel element was irradiated to a peak burnup of 54,000 MWd/MT at a peak power rating of 14.8 kW/ft and a maximum outside surface temperature of 685 +- 15 0 C. The maximum diametral increase of the element was 0.2% ΔD/D. Volatile fission products migrated to the ends of the fuel column but had not been transported beyond the blanket region of the element. Fission-product attack of the cladding was found to a depth of 4.4 mils adjacent to the mixed-oxide fuel. The maximum fission-product attack (approximately 6.2 mils) was found adjacent to slightly hyperstoichiometric UO 2 pellets at the upper end of the fuel column. The more severe attack in this region has been attributed to the higher oxygen potential adjacent to the hyperstoichiometric UO 2 fuel. A stress-rupture test was performed on a section of the element. The cladding ruptured after 30 min at 700 0 C and approximately 21,500-psi loop stress, resulting in a diametral strain of 1.6%

  18. 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...

  19. 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.

  20. [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.

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

    Directory of Open Access Journals (Sweden)

    Simona BUTA

    2013-12-01

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

  2. 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 ...

  3. Cash seeking behaviour and migration: a place-to-place migration function for Cote d'Ivoire.

    Science.gov (United States)

    Velenchik, A D

    1993-12-01

    "This paper presents estimates of an aggregate place-to-place migration function for Cote d'Ivoire based on the premise that migration is motivated by rural residents' desire for cash income. The results indicate that migration from a region responds differently to changes in cash and food income, which supports the idea that it is the composition of rural income, and not just its level, that determines migration flows." excerpt

  4. Current-induced changes of migration energy barriers in graphene and carbon nanotubes

    Science.gov (United States)

    Obodo, J. T.; Rungger, I.; Sanvito, S.; Schwingenschlögl, U.

    2016-05-01

    An electron current can move atoms in a nanoscale device with important consequences for the device operation and breakdown. We perform first principles calculations aimed at evaluating the possibility of changing the energy barriers for atom migration in carbon-based systems. In particular, we consider the migration of adatoms and defects in graphene and carbon nanotubes. Although the current-induced forces are large for both the systems, in graphene the force component along the migration path is small and therefore the barrier height is little affected by the current flow. In contrast, the same barrier is significantly reduced in carbon nanotubes as the current increases. Our work also provides a real-system numerical demonstration that current-induced forces within density functional theory are non-conservative.An electron current can move atoms in a nanoscale device with important consequences for the device operation and breakdown. We perform first principles calculations aimed at evaluating the possibility of changing the energy barriers for atom migration in carbon-based systems. In particular, we consider the migration of adatoms and defects in graphene and carbon nanotubes. Although the current-induced forces are large for both the systems, in graphene the force component along the migration path is small and therefore the barrier height is little affected by the current flow. In contrast, the same barrier is significantly reduced in carbon nanotubes as the current increases. Our work also provides a real-system numerical demonstration that current-induced forces within density functional theory are non-conservative. Electronic supplementary information (ESI) available. See DOI: 10.1039/C6NR00534A

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

    International Nuclear Information System (INIS)

    Palagyi, S.; Palagyiova, J.

    2003-01-01

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

  6. Review of Andrés Solimano, International Migration in the Age of Crisis and Globalisation. Historical and Recent Experiences, Cambridge University Press, 2010. 223 Pp.

    Directory of Open Access Journals (Sweden)

    Dirina Claudiu – Ciprian

    2015-12-01

    Full Text Available “International Migration in the Age of Crisis and Globalization. Historical and Recent Experiences” represents a work of major interest in the field of migration and globalization. Apparently two concepts that relate one to another, on a background of major population dynamics, the two notions are the two important pillars in what might perfectly be described as a complex analysis of migration, starting from the elements that have initiated it, and culminating with a fine comparison of positive and negative aspects of this phenomenon.

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

    Science.gov (United States)

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

    2017-01-01

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

  8. Migration study of americium in porous medium

    International Nuclear Information System (INIS)

    Tanaka, Tadao; Ogawa, Hiromichi

    1999-01-01

    Migration experiments of 241 Am 3+ had been performed by a column system, to investigate migration behavior of 241 Am through a column packed porous sedimentary materials: a coastal sandy soil and a reddish soil. Most 241 Am loaded into the column packed the reddish soil sorbed on the influent edge of the column. In the case of the sandy soil, however, considerable amount of 241 Am was passed through the column. This shows that there is colloidal 241 Am species which may move without effective interaction with the sandy soil. Such a migration behavior of colloidal 241 Am in the sandy soil column could be evaluated by a sorption model based on filtration theory. Sorption mechanisms of 241 Am on the sedimentary materials were examined by a chemical extraction method, for 241 Am sorbed on the sandy soil and the reddish soil at any sections in the column. The 241 Am sorbed on the reddish soil was mainly controlled by a reversible ion exchange reaction. On the other hand, the 241 Am sorbed on the sandy soil ws controlled by irreversible reactions, such as the selective chemical sorptions onto Fe and Mn oxyhydroxide/oxide. The experimental results support that the migration of 241 Am in the reddish soil layer can be estimated by using the K d , whereas that in the sandy soil can not be explained by the K d concept. (author)

  9. 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...

  10. Diffusion coefficients of alloying elements in dilute Mg alloys: A comprehensive first-principles study

    International Nuclear Information System (INIS)

    Zhou, Bi-Cheng; Shang, Shun-Li; Wang, Yi; Liu, Zi-Kui

    2016-01-01

    First-principles calculations based on density functional theory have been used to calculate the temperature-dependent dilute tracer diffusion coefficients for 47 substitutional alloying elements in hexagonal closed packed (hcp) Mg by combining transition state theory and an 8-frequency model. The minimum energy pathways and the saddle point configurations during solute migration are calculated with the climbing image nudged elastic band method. Vibrational properties are obtained using the quasi-harmonic Debye model with inputs from first-principles calculations. An improved generalized gradient approximation of PBEsol is used in the present first-principles calculations, which is able to well describe both vacancy formation energies and vibrational properties. It is found that the solute diffusion coefficients in hcp Mg are roughly inversely proportional to the bulk modulus of the dilute alloys, which reflects the solutes' bonding to Mg. Transition metal elements with d electrons show strong interactions with Mg and have large diffusion activation energies. Correlation effects are not negligible for solutes Ca, Na, Sr, Se, Te, and Y, in which the direct solute migration barriers are much smaller than the solvent (Mg) migration barriers. Calculated diffusion coefficients are in remarkable agreement with available experimental data in the literature.

  11. 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.

  12. Evaluating indices of lipid and protein content in lesser snow and Ross's geese during spring migration

    Science.gov (United States)

    Webb, Elisabeth B.; Fowler, Drew N.; Woodall, Brendan A.; Vrtiska, Mark P.

    2018-01-01

    Assessing nutrient stores in avian species is important for understanding the extent to which body condition influences success or failure in life‐history events. We evaluated predictive models using morphometric characteristics to estimate total body lipids (TBL) and total body protein (TBP), based on traditional proximate analyses, in spring migrating lesser snow geese (Anser caerulescens caerulescens) and Ross's geese (A. rossii). We also compared performance of our lipid model with a previously derived predictive equation for TBL developed for nesting lesser snow geese. We used external and internal measurements on 612 lesser snow and 125 Ross's geese collected during spring migration in 2015 and 2016 within the Central and Mississippi flyways to derive and evaluate predictive models. Using a validation data set, our best performing lipid model for snow geese better predicted TBL (root mean square error [RMSE] of 23.56) compared with a model derived from nesting individuals (RMSE = 48.60), suggesting the importance of season‐specific models for accurate lipid estimation. Models that included body mass and abdominal fat deposit best predicted TBL determined by proximate analysis in both species (lesser snow goose, R2 = 0.87, RMSE = 23.56: Ross's geese, R2 = 0.89, RMSE = 13.75). Models incorporating a combination of external structural measurements in addition to internal muscle and body mass best predicted protein values (R2 = 0.85, RMSE = 19.39 and R2 = 0.85, RMSE = 7.65, lesser snow and Ross's geese, respectively), but protein models including only body mass and body size were also competitive and provided extended utility to our equations for field applications. Therefore, our models indicated the importance of specimen dissection and measurement of the abdominal fat pad to provide the most accurate lipid estimates and provide alternative dissection‐free methods for estimating protein.

  13. The Transformative Forces of Migration: Refugees and the Re-Configuration of Migration Societies

    Directory of Open Access Journals (Sweden)

    Ulrike Hamann

    2018-03-01

    Full Text Available In this thematic issue, we attempt to show how migrations transform societies at the local and micro level by focusing on how migrants and refugees navigate within different migration regimes. We pay particular attention to the specific formation of the migration regimes that these countries adopt, which structure the conditions of the economic, racialised, gendered, and sexualized violence and exploitation during migration processes. This interactive process of social transformation shapes individual experiences while also being shaped by them. We aim to contribute to the most recent and challenging question of what kind of political and social changes can be observed and how to frame these changes theoretically if we look at local levels while focusing on struggles for recognition, rights, and urban space. We bring in a cross-country comparative perspective, ranging from Canada, Chile, Spain, Sweden, Turkey, and to Germany in order to lay out similarities and differences in each case, within which our authors analyse these transformative forces of migration.

  14. Security Enhancement for Data Migration in the Cloud

    Directory of Open Access Journals (Sweden)

    Jean Raphael Ngnie Sighom

    2017-06-01

    Full Text Available In today’s society, cloud computing has significantly impacted nearly every section of our lives and business structures. Cloud computing is, without any doubt, one of the strategic directions for many companies and the most dominating infrastructure for enterprises as long as end users. Instead of buying IT equipment (hardware and/or software and managing it themselves, many organizations today prefer to buy services from IT service providers. The number of service providers increase dramatically and the cloud is becoming the tools of choice for more cloud storage services. However, as more personal information and data are moved to the cloud, into social media sites, DropBox, Baidu WangPan, etc., data security and privacy issues are questioned. Daily, academia and industry seek to find an efficient way to secure data migration in the cloud. Various solution approaches and encryption techniques have been implemented. In this work, we will discuss some of these approaches and evaluate the popular ones in order to find the elements that affect system performance. Finally, we will propose a model that enhances data security and privacy by combining Advanced Encryption Standard-256, Information Dispersal Algorithms and Secure Hash Algorithm-512. Our protocol achieves provable security assessments and fast execution times for medium thresholds.

  15. Evaluation of maximum radionuclide concentration from decay chains migration in aquifers

    International Nuclear Information System (INIS)

    Aquino Branco, O.E. de.

    1983-01-01

    The mathematical formulation of the mechanisms involved in the transport of contaminants in aquifers is presented. The methodology employed is described. A method of calculation the maximum concentration of radionuclides migrating in the underground water, and resulting from one decay chain, is then proposed. As an example, the methodology is applied to a waste basin, built to receive effluents from a hypothectical uranium ore mining and milling facility. (M.A.C.) [pt

  16. 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

  17. The effect of vadose zone heterogeneities on vapor phase migration and aquifer contamination by volatile organics

    Energy Technology Data Exchange (ETDEWEB)

    Seneviratne, A.; Findikakis, A.N. [Bechtel Corporation, San Francisco, CA (United States)

    1995-03-01

    Organic vapors migrating through the vadose zone and inter-phase transfer can contribute to the contamination of larger portions of aquifers than estimated by accounting only for dissolved phase transport through the saturated zone. Proper understanding of vapor phase migration pathways is important for the characterization of the extent of both vadose zone and the saturated zone contamination. The multiphase simulation code T2VOC is used to numerically investigate the effect of heterogeneties on the vapor phase migration of chlorobenzene at a hypothetical site where a vapor extraction system is used to remove contaminants. Different stratigraphies consisting of alternate layers of high and low permeability materials with soil properties representative of gravel, sandy silt and clays are evaluated. The effect of the extent and continuity of low permeability zones on vapor migration is evaluated. Numerical simulations are carried out for different soil properties and different boundary conditions. T2VOC simulations with zones of higher permeability were made to assess the role of how such zones in providing enhanced migration pathways for organic vapors. Similarly, the effect of the degree of saturation of the porous medium on vapor migration was for a range of saturation values. Increased saturation reduces the pore volume of the medium available for vapor diffusion. Stratigraphic units with higher aqueous saturation can retard the vapor phase migration significantly.

  18. Cluster analysis to evaluate stable chemical elements and physical-chemical parameters behavior on uranium mining waste

    International Nuclear Information System (INIS)

    Pereira, Wagner de Souza; Py Junior, Delcy de Azevedo; Goncalves, Simone; Kelecom, Alphonse; Morais, Gustavo Ferrari de; Campelo, Emanuele Lazzaretti Cordova; Dores, Luis Augusto de Carvalho Bresser

    2011-01-01

    The Ore Treating Unit (UTM, in portuguese) is a deactivated uranium mine. A cluster analysis was used to evaluate the behavior of stable chemical elements and physical-chemical parameters in their effluents. The utilization of the cluster analysis proved itself effective in the assessment, allowing the identification of groups of chemical elements, physical-chemical parameters and their joint analysis (elements and parameters). As a result we may assert, based on data analysis, that there is a strong link between calcium and magnesium and between aluminum and rare-earth oxides on UTM's effluents. Sulphate was also identified as strongly linked to total and dissolved solids, and those to electrical conductivity. There were other associations, but not so strongly linked. Further gathering, to seasonal evaluation, are required in order to confirm those analysis. Additional statistical analysis (factor analysis) must be used to try to identify the origin of the identified groups on this analysis. (author)

  19. Cluster analysis to evaluate stable chemical elements and physical-chemical parameters behavior on uranium mining waste

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner de Souza; Py Junior, Delcy de Azevedo; Goncalves, Simone, E-mail: wspereira@inb.gov.br [Unidade de Tratamento de Minerio (UTM/INB), Pocos de Caldas, MG (Brazil). Coordenacao de Protecao Radiologica. Grupo Multidisciplinar de Radioprotecao; Kelecom, Alphonse [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Biologia. Lab. de Radiobiologia e Radiometria Pedro Lopes dos Santos; Morais, Gustavo Ferrari de; Campelo, Emanuele Lazzaretti Cordova [Unidade de Tratamento de Minerio (UTM/INB), Pocos de Caldas, MG (Brazil). Coordenacao de Desenvolvimento de Processos; Dores, Luis Augusto de Carvalho Bresser [Unidade de Tratamento de Minerio (UTM/INB), Pocos de Caldas, MG (Brazil). Gerencia de Descomissionamento

    2011-07-01

    The Ore Treating Unit (UTM, in portuguese) is a deactivated uranium mine. A cluster analysis was used to evaluate the behavior of stable chemical elements and physical-chemical parameters in their effluents. The utilization of the cluster analysis proved itself effective in the assessment, allowing the identification of groups of chemical elements, physical-chemical parameters and their joint analysis (elements and parameters). As a result we may assert, based on data analysis, that there is a strong link between calcium and magnesium and between aluminum and rare-earth oxides on UTM's effluents. Sulphate was also identified as strongly linked to total and dissolved solids, and those to electrical conductivity. There were other associations, but not so strongly linked. Further gathering, to seasonal evaluation, are required in order to confirm those analysis. Additional statistical analysis (factor analysis) must be used to try to identify the origin of the identified groups on this analysis. (author)

  20. Surface coating for prevention of metallic seed migration in tissues

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyunseok; Park, Jong In [Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, Won Seok; Park, Min [Interdisciplinary Program in Bioengineering, Seoul National University College of Engineering, Seoul 151-742 (Korea, Republic of); Son, Kwang-Jae [Hanaro Applications Research, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Bang, Young-bong [Advanced Institutes of Convergence Technology, Seoul National University, Suwon 443-270 (Korea, Republic of); Choy, Young Bin, E-mail: ybchoy@snu.ac.kr, E-mail: sye@snu.ac.kr [Interdisciplinary Program in Bioengineering, Seoul National University College of Engineering, Seoul 110-744 (Korea, Republic of); Department of Biomedical Engineering, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Institute of Medical and Biological Engineering, Medical Research Center, Seoul National University, Seoul 110-744 (Korea, Republic of); Ye, Sung-Joon, E-mail: ybchoy@snu.ac.kr, E-mail: sye@snu.ac.kr [Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742 (Korea, Republic of); Advanced Institutes of Convergence Technology, Seoul National University, Suwon 443-270 (Korea, Republic of); Department of Radiation Oncology, Seoul National University Hospital, Seoul 110-744 (Korea, Republic of)

    2015-06-15

    Purpose: In radiotherapy, metallic implants often detach from their deposited sites and migrate to other locations. This undesirable migration could cause inadequate dose coverage for permanent brachytherapy and difficulties in image-guided radiation delivery for patients. To prevent migration of implanted seeds, the authors propose a potential strategy to use a biocompatible and tissue-adhesive material called polydopamine. Methods: In this study, nonradioactive dummy seeds that have the same geometry and composition as commercial I-125 seeds were coated in polydopamine. Using scanning electron microscopy and x-ray photoelectron spectroscopy, the surface of the polydopamine-coated and noncoated seeds was characterized. The detachment stress between the two types of seeds and the tissue was measured. The efficacy of polydopamine-coated seed was investigated through in vitro migration tests by tracing the seed location after tissue implantation and shaking for given times. The cytotoxicity of the polydopamine coating was also evaluated. Results: The results of the coating characterization have shown that polydopamine was successfully coated on the surface of the seeds. In the adhesion test, the polydopamine-coated seeds had 2.1-fold greater detachment stress than noncoated seeds. From the in vitro test, it was determined that the polydopamine-coated seed migrated shorter distances than the noncoated seed. This difference was increased with a greater length of time after implantation. Conclusions: The authors suggest that polydopamine coating is an effective technique to prevent migration of implanted seeds, especially for permanent prostate brachytherapy.

  1. How neurons migrate: a dynamic in-silico model of neuronal migration in the developing cortex

    LENUS (Irish Health Repository)

    Setty, Yaki

    2011-09-30

    Abstract Background Neuronal migration, the process by which neurons migrate from their place of origin to their final position in the brain, is a central process for normal brain development and function. Advances in experimental techniques have revealed much about many of the molecular components involved in this process. Notwithstanding these advances, how the molecular machinery works together to govern the migration process has yet to be fully understood. Here we present a computational model of neuronal migration, in which four key molecular entities, Lis1, DCX, Reelin and GABA, form a molecular program that mediates the migration process. Results The model simulated the dynamic migration process, consistent with in-vivo observations of morphological, cellular and population-level phenomena. Specifically, the model reproduced migration phases, cellular dynamics and population distributions that concur with experimental observations in normal neuronal development. We tested the model under reduced activity of Lis1 and DCX and found an aberrant development similar to observations in Lis1 and DCX silencing expression experiments. Analysis of the model gave rise to unforeseen insights that could guide future experimental study. Specifically: (1) the model revealed the possibility that under conditions of Lis1 reduced expression, neurons experience an oscillatory neuron-glial association prior to the multipolar stage; and (2) we hypothesized that observed morphology variations in rats and mice may be explained by a single difference in the way that Lis1 and DCX stimulate bipolar motility. From this we make the following predictions: (1) under reduced Lis1 and enhanced DCX expression, we predict a reduced bipolar migration in rats, and (2) under enhanced DCX expression in mice we predict a normal or a higher bipolar migration. Conclusions We present here a system-wide computational model of neuronal migration that integrates theory and data within a precise

  2. How neurons migrate: a dynamic in-silico model of neuronal migration in the developing cortex

    Directory of Open Access Journals (Sweden)

    Skoblov Nikita

    2011-09-01

    Full Text Available Abstract Background Neuronal migration, the process by which neurons migrate from their place of origin to their final position in the brain, is a central process for normal brain development and function. Advances in experimental techniques have revealed much about many of the molecular components involved in this process. Notwithstanding these advances, how the molecular machinery works together to govern the migration process has yet to be fully understood. Here we present a computational model of neuronal migration, in which four key molecular entities, Lis1, DCX, Reelin and GABA, form a molecular program that mediates the migration process. Results The model simulated the dynamic migration process, consistent with in-vivo observations of morphological, cellular and population-level phenomena. Specifically, the model reproduced migration phases, cellular dynamics and population distributions that concur with experimental observations in normal neuronal development. We tested the model under reduced activity of Lis1 and DCX and found an aberrant development similar to observations in Lis1 and DCX silencing expression experiments. Analysis of the model gave rise to unforeseen insights that could guide future experimental study. Specifically: (1 the model revealed the possibility that under conditions of Lis1 reduced expression, neurons experience an oscillatory neuron-glial association prior to the multipolar stage; and (2 we hypothesized that observed morphology variations in rats and mice may be explained by a single difference in the way that Lis1 and DCX stimulate bipolar motility. From this we make the following predictions: (1 under reduced Lis1 and enhanced DCX expression, we predict a reduced bipolar migration in rats, and (2 under enhanced DCX expression in mice we predict a normal or a higher bipolar migration. Conclusions We present here a system-wide computational model of neuronal migration that integrates theory and data within a

  3. 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.

  4. Accurate evaluation of exchange fields in finite element micromagnetic solvers

    Science.gov (United States)

    Chang, R.; Escobar, M. A.; Li, S.; Lubarda, M. V.; Lomakin, V.

    2012-04-01

    Quadratic basis functions (QBFs) are implemented for solving the Landau-Lifshitz-Gilbert equation via the finite element method. This involves the introduction of a set of special testing functions compatible with the QBFs for evaluating the Laplacian operator. The results by using QBFs are significantly more accurate than those via linear basis functions. QBF approach leads to significantly more accurate results than conventionally used approaches based on linear basis functions. Importantly QBFs allow reducing the error of computing the exchange field by increasing the mesh density for structured and unstructured meshes. Numerical examples demonstrate the feasibility of the method.

  5. Migration Processes Provoked yy the Break-Up of Yugoslavia and the Agression against Croatia

    Directory of Open Access Journals (Sweden)

    Mirjana Domini

    1999-10-01

    Full Text Available The paper deals with forced migration caused by Serb aggression in areas of Croatia and the neighbouring countries. The first part presents the relevant facts relating to Croatia and important for an understanding of the migration flows (some demographic data as well as the basic guidelines of migration policy, legal regulations and most important problems connected with expellees, refugees and displaced persons. The main elements of contemporary migration movements in Croatia are indicated – migration based on economic causes (traditional migration, migration provoked by crisis and war destruction in former Yugoslavia and migration flows that are difficult to register (mainly clandestine crossings of the border of the Republic of Croatia and the irregular labour market. The author states that the expellee, refugee and displaced persons crisis (with psychological and material repercussions began in 1991 and reached a climax in 1992 when Croatia became one of the most pronounced refugee countries in the world, with refugees accounting for about 15% of its population. As the war crisis shifted, the areas from which intense forced migration to and from Croatia resulted also shifted as did the mechanisms for regulating these forced migrations (dual citizenship, transit visas, accords with "third countries" for accepting refugees and expellees, ways of resolving and caring for the refugee-expellee populations in the Republic of Croatia. The author concludes that even after seven years from the start of the aggression against Croatia, this humanitarian crisis among expellees, refugees and displaced persons has not yet finished, as testified by the new military conflict in Kosovo and by many open questions in regard to the future organisation of states in this crisis area as well as the creation of mechanisms for monitoring potential conflicts. A fundamental idea is expressed throughout the paper – i.e. the notion that now it is maybe more

  6. Geochemical characterization and heavy metal migration in a coastal polluted aquifer incorporating tidal effects: field investigation in Chongming Island, China.

    Science.gov (United States)

    Liu, Shuguang; Tan, Bo; Dai, Chaomeng; Lou, Sha; Tao, An; Zhong, Guihui

    2015-12-01

    The occurrence and migration of heavy metal in coastal aquifer incorporating tidal effects were investigated in detail by the field geological survey and observation. The continuous groundwater sampling, field observation (for groundwater potentiometric surface elevation, pH, dissolved oxygen, temperature, and salinity), and laboratory analysis (for Cr, Ni, Cu, Zn, Cd, and Pb concentration) were conducted through eight monitoring wells located around the landfill in the northern part of Chongming Island, China. The results showed that the unconfined aquifer medium was estuary-littoral facies deposit of Holocene, mainly gray clayey silt and grey sandy silt, and the groundwater flow was mainly controlled by topography condition of the aquifer formation strike. The background values of Cr, Ni, Cu, Zn, Cd, and Pb in Chongming Island were 3.10 ± 3.09, 0.81 ± 0.25, 1.48 ± 1.09, 43.32 ± 33.06, 0.08 ± 0.16, and 0.88 ± 1.74 μg/L, respectively. Compared with the groundwater samples around the study area, the drinking water was qualified and was free from the seawater intrusion/estuarine facies contaminant encroachment. Pollutant discharge was reflected in water quality parameters, the Cr and Cu concentrations elevated to the peak of 50.07 and 46.00 μg/L, respectively, and meanwhile specific migration regularity was embodied in observation time series as well as other elements. This migration regularity was not fully identical according to correlations between these analyzed elements. Ambient watery environment, anthropogenic disturbance, regional hydrogeological condition, and biogeochemical reactivity on heavy metals reduced/altered the significance of elements correlation in the migration pathway in coastal aquifer.

  7. Effect of microbial processes on transuranium elements behaviour in soil, plants and animal organism

    International Nuclear Information System (INIS)

    Uajldung, R.Eh.; Garlend, T.P.

    1985-01-01

    Results of preliminary studies discussed in the present paper bring about the supposition that concentration and chemical from of an element in a plant play an essential role in variation of its availability for animals consuming plants. That is why any assessment of long-term behaviour of transuranium elements in terrestrialenvironment should be based on determination of factors affecting solubility and forms of soluble compounds in soil. These factors include concentration and chemical form of the element migrating to soil; effect of the properties of soil on element distribution between solid and liquid phases; effect soil processes on kinetics of sorption reactions, concentration of transuranium elements, forms of soluble and non-soluble chemical compounds

  8. Migration processes in SCO member states

    Directory of Open Access Journals (Sweden)

    Valentina Sergeevna Antonyuk

    2012-12-01

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

  9. Multiple spring migration strategies in a population of Pacific Common Eiders

    Science.gov (United States)

    Petersen, M.R.

    2009-01-01

    Spring migration strategies vary within and among species. Examination of this variability extends our understanding of life histories and has implications for conservation. I used satellite transmitters to determine migration strategies and evaluate factors influencing the timing of spring migration of Pacific Common Eiders (Somateria mollissima v-nigrum) that nest along the western Beaufort Sea coast. Adult females were marked at nesting colonies in the summers of 2000, 2001, and 2003, and were followed throughout spring migration the following year. Each year approximately equal proportions of eiders used three distinct migration strategies varying in duration, staging locations (waters near the Chukotka Peninsula, Russia, and the Chukchi and Beaufort seas, Alaska), and arrival dates at the nesting areas. It is unlikely that differences in the timing of movements to stopover sites in the Chukchi and Beaufort seas were a result of responses to changes in weather, particularly wind direction. Ice distribution and melt/movement patterns vary substantially among staging areas and thus may affect risk of starvation and reproductive potential. Long-term (decadal) changes in climate may favor birds using one strategy during "warmer" and another during "colder" years. ?? 2009 by The Cooper Ornithological Society. All rights reserved.

  10. CT and MR evaluation of migrational disorders of the brain. Pt. 2. Schizencephaly, heterotopia and polymicrogyria

    Energy Technology Data Exchange (ETDEWEB)

    Byrd, S E; Osborn, R E; Bohan, T P; Naidich, T P

    1989-05-01

    The migrational disorders are a rare group of congenital malformations of the brain. They consist of the following entities - lissencephaly (agyria - pachygyria), pachygyria, schizencephaly, heterotopia and polymicrogyria. We studied 40 children with migrational disorders radiologically with CT and MR. This article (Part II) deals with our patients with schizencephaly, heterotopia and polymicrogyria. These patients presented clinically with a variety of symptoms. The most common were seizures, delayed development, failure to thrive and hydrocephalus. CT and MR both demonstrated the characteristic findings in all of our patients except the polymicrogyria group. The gray matter and cleft abnormalities seen in these disorders were demonstrated with CT and MR. However, MR provided better delineation of these disorders than CT. Because some forms of migrational disorders can be inherited, it is extremely important for the radiologist to understand the characteristic findings for correct diagnosis which is essential for parental counseling.

  11. Short-term organic carbon migration from polymeric materials in contact with chlorinated drinking water.

    Science.gov (United States)

    Mao, Guannan; Wang, Yingying; Hammes, Frederik

    2018-02-01

    Polymeric materials are widely used in drinking water distribution systems. These materials could release organic carbon that supports bacterial growth. To date, the available migration assays for polymeric materials have not included the potential influence of chlorination on organic carbon migration behavior. Hence, we established a migration and growth potential protocol specifically for analysis of carbon migration from materials in contact with chlorinated drinking water. Four different materials were tested, including ethylene propylene dienemethylene (EPDM), poly-ethylene (PEX b and PEX c) and poly-butylene (PB). Chlorine consumption rates decreased gradually over time for EPDM, PEXc and PB. In contrast, no free chlorine was detected for PEXb at any time during the 7 migration cycles. Total organic carbon (TOC) and assimilable organic carbon (AOC) was evaluated in both chlorinated and non-chlorinated migrations. TOC concentrations for EPDM and PEXb in chlorinated migrations were significantly higher than non-chlorinated migrations. The AOC results showed pronounced differences among tested materials. AOC concentrations from chlorinated migration waters of EPDM and PB were higher compared to non-chlorinated migrations, whereas the opposite trend was observed for PEXb and PEXc. There was also a considerable difference between tested materials with regards to bacterial growth potential. The results revealed that the materials exposed to chlorine-influenced migration still exhibited a strong biofilm formation potential. The overall results suggested that the choice in material would make a considerable difference in chlorine consumption and carbon migration behavior in drinking water distribution systems. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2015-01-01

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

  13. 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...

  14. Evaluation of Concrete Cylinder Tests Using Finite Elements

    DEFF Research Database (Denmark)

    Saabye Ottosen, Niels

    1984-01-01

    Nonlinear axisymmetric finite element analyses are performed on the uniaxial compressive test of concrete cylinders. The models include thick steel loading plates, and cylinders with height‐to‐diameter ratios (h/d) ranging from 1‐3 are treated. A simple constitutive model of the concrete is emplo......Nonlinear axisymmetric finite element analyses are performed on the uniaxial compressive test of concrete cylinders. The models include thick steel loading plates, and cylinders with height‐to‐diameter ratios (h/d) ranging from 1‐3 are treated. A simple constitutive model of the concrete...... uniaxial strength the use of geometrically matched loading plates seems to be advantageous. Finally, it is observed that for variations of the element size within limits otherwise required to obtain a realistic analysis, the results are insensitive to the element size....

  15. Experimental Study of Elements Promoting Mixing in Fuel Elements

    International Nuclear Information System (INIS)

    Silin, Nicolas; Juanico, Luis; Delmastro, Dario

    2003-01-01

    In the present work a thermal tracing technique is used to measure the increase of the mixing between subchannels in the presence of different mixing elements.As representative elements a spacer, a spacer with mixing vanes and turbulence promoter buttons were considered.The performance of these elements was evaluated by studying the behavior of a thermal trace in each case.Also the pressure drop for each case is presented.The results present a qualitative and quantitative guide for the application of each one of these appendages in future nuclear elements

  16. Automated estimation of hip prosthesis migration: a feasibility study

    Science.gov (United States)

    Vandemeulebroucke, Jef; Deklerck, Rudi; Temmermans, Frederik; Van Gompel, Gert; Buls, Nico; Scheerlinck, Thierry; de Mey, Johan

    2013-09-01

    A common complication associated with hip arthoplasty is prosthesis migration, and for most cemented components a migration greater than 0.85 mm within the first six months after surgery, are an indicator for prosthesis failure. Currently, prosthesis migration is evaluated using X-ray images, which can only reliably estimate migrations larger than 5 mm. We propose an automated method for estimating prosthesis migration more accurately, using CT images and image registration techniques. We report on the results obtained using an experimental set-up, in which a metal prosthesis can be translated and rotated with respect to a cadaver femur, over distances and angles applied using a combination of positioning stages. Images are first preprocessed to reduce artefacts. Bone and prosthesis are extracted using consecutive thresholding and morphological operations. Two registrations are performed, one aligning the bones and the other aligning the prostheses. The migration is estimated as the difference between the found transformations. We use a robust, multi-resolution, stochastic optimization approach, and compare the mean squared intensity differences (MS) to mutual information (MI). 30 high-resolution helical CT scans were acquired for prosthesis translations ranging from 0.05 mm to 4 mm, and rotations ranging from 0.3° to 3° . For the translations, the mean 3D registration error was found to be 0.22 mm for MS, and 0.15 mm for MI. For the rotations, the standard deviation of the estimation error was 0.18° for MS, and 0.08° for MI. The results show that the proposed approach is feasible and that clinically acceptable accuracies can be obtained. Clinical validation studies on patient images will now be undertaken.

  17. Interactions of trace elements with fracture filling minerals from the Aespoe Hard Rock Laboratory

    International Nuclear Information System (INIS)

    Landstroem, O.; Tullborg, E.L.

    1995-06-01

    This report focuses on the distribution of stable elements and natural radionuclides (e.g. REEs, Th, Ra, Sr and Cs) in natural fracture systems. They have been redistributed by natural processes in the past; mobilization, transport and deposition of which the latter is manifested as 'enrichments' of the elements in fracture fillings. Fillings dominated by Fe-oxyhydroxide, calcite and clay minerals show the highest concentrations. Precipitates from different fractures show large variations in concentration levels of trace elements, REE patterns, and activity and activity ratios of natural radionuclides, reflecting variations in physical, chemical and hydrological properties of the fractures. The incorporation of REEs, Sr, Th and U in calcite is significant. The precipitation rate influences the amount of Sr incorporated and probably other elements as well. Clay minerals have high sorption capacity and are important in the retention of Cs and Sr as well as of REEs, Th, U and Ra. The importance of clay minerals in radionuclide retention is emphasized by the results from this study, even small amounts of clay minerals in fractures and fracture zones can significantly influence the radionuclide migration. Accurate determination of quantities and types of clay minerals is therefore very important for radionuclide migration modelling. 58 refs, 14 figs, 12 tabs

  18. Interactions of trace elements with fracture filling minerals from the Aespoe Hard Rock Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Landstroem, O [Studsvik Eco and Safety AB, Nykoeping (Sweden); Tullborg, E L [Terralogica AB (Sweden)

    1995-06-01

    This report focuses on the distribution of stable elements and natural radionuclides (e.g. REEs, Th, Ra, Sr and Cs) in natural fracture systems. They have been redistributed by natural processes in the past; mobilization, transport and deposition of which the latter is manifested as `enrichments` of the elements in fracture fillings. Fillings dominated by Fe-oxyhydroxide, calcite and clay minerals show the highest concentrations. Precipitates from different fractures show large variations in concentration levels of trace elements, REE patterns, and activity and activity ratios of natural radionuclides, reflecting variations in physical, chemical and hydrological properties of the fractures. The incorporation of REEs, Sr, Th and U in calcite is significant. The precipitation rate influences the amount of Sr incorporated and probably other elements as well. Clay minerals have high sorption capacity and are important in the retention of Cs and Sr as well as of REEs, Th, U and Ra. The importance of clay minerals in radionuclide retention is emphasized by the results from this study, even small amounts of clay minerals in fractures and fracture zones can significantly influence the radionuclide migration. Accurate determination of quantities and types of clay minerals is therefore very important for radionuclide migration modelling. 58 refs, 14 figs, 12 tabs.

  19. Intraosseous migration of tendinous calcifications: two case reports

    Energy Technology Data Exchange (ETDEWEB)

    Marinetti, A.; Sessa, M.; Falzone, A.; Della Sala, S.W. [Santa Maria del Carmine Hospital, Department of Radiology, Rovereto, TN (Italy)

    2018-01-15

    Calcific tendinopathy of the rotator cuff is a common cause of shoulder pain. Inflammation of the rotator cuff tendons may be complicated by adjacent bone erosion and subsequent migration of calcific deposits within the bone resulting in marrow inflammation. Bone marrow involvement is not readily visible using X-ray and ultrasound (US) and further testing is necessary. Magnetic resonance imaging (MRI) is a highly sensitive technique that can detect a focal bone T1 and T2-weighted hypointensity with bone marrow edema-like signal and cortical erosion. These findings can mislead the radiologist by suggesting an infectious or neoplastic lesion, often requiring further evaluation with computed tomography (CT) and biopsy. We report two cases of patients with shoulder pain in which different radiological approaches were used with pathological confirmation in one of them. In the first case, MRI revealed significant bone involvement in the head of the humerus and cortical erosion of the greater tuberosity. A CT examination and a biopsy was necessary for a final diagnosis of inflammatory bone reaction from intraosseous migration of tendinous calcifications. In the second case, similar MRI findings prompted re-evaluation of imaging to make a diagnosis of intraosseous migration of tendinous calcifications, obviating the need to perform CT and biopsy. We illustrate MRI signs of this complication that we think would allow to narrow the differential diagnosis potentially avoiding biopsy and additional CT examinations. (orig.)

  20. Intraosseous migration of tendinous calcifications: two case reports

    International Nuclear Information System (INIS)

    Marinetti, A.; Sessa, M.; Falzone, A.; Della Sala, S.W.

    2018-01-01

    Calcific tendinopathy of the rotator cuff is a common cause of shoulder pain. Inflammation of the rotator cuff tendons may be complicated by adjacent bone erosion and subsequent migration of calcific deposits within the bone resulting in marrow inflammation. Bone marrow involvement is not readily visible using X-ray and ultrasound (US) and further testing is necessary. Magnetic resonance imaging (MRI) is a highly sensitive technique that can detect a focal bone T1 and T2-weighted hypointensity with bone marrow edema-like signal and cortical erosion. These findings can mislead the radiologist by suggesting an infectious or neoplastic lesion, often requiring further evaluation with computed tomography (CT) and biopsy. We report two cases of patients with shoulder pain in which different radiological approaches were used with pathological confirmation in one of them. In the first case, MRI revealed significant bone involvement in the head of the humerus and cortical erosion of the greater tuberosity. A CT examination and a biopsy was necessary for a final diagnosis of inflammatory bone reaction from intraosseous migration of tendinous calcifications. In the second case, similar MRI findings prompted re-evaluation of imaging to make a diagnosis of intraosseous migration of tendinous calcifications, obviating the need to perform CT and biopsy. We illustrate MRI signs of this complication that we think would allow to narrow the differential diagnosis potentially avoiding biopsy and additional CT examinations. (orig.)

  1. Electrochemical migration, whisker formation, and corrosion behavior of printed circuit board under wet H2S environment

    International Nuclear Information System (INIS)

    Zou, Shiwen; Li, Xiaogang; Dong, Chaofang; Ding, Kangkang; Xiao, Kui

    2013-01-01

    Highlights: •The electrochemical migration, whisker formation, and corrosion behavior of PCB under wet H 2 S environment were observed and studied systematically. •The process of electrochemical migration of solder joints is explained. •The corrosion mechanism of PCB interconnectors induced by micro pores under wet H 2 S environment is discussed, and the corrosion reaction model is proposed. -- Abstract: Electrochemical migration, whisker formation, and corrosion behavior of printed circuit board (PCB) under wet H 2 S environment were analyzed by environment scanning electron microscope (ESEM), Energy dispersive X-ray spectroscopy (EDS) with mapping and element phase cluster (EPC) techniques, Raman Spectrum analysis and electrochemical impedance spectroscopy (EIS) technology. The results showed that nonuniform corrosion behavior occurred on PCB surfaces under 1 ppm wet H 2 S at 40 °C; whiskers formed on the inner sidewall of via-holes with a growth rate of 1.2 Å/s; numerous corrosion products migrated through the pore of plated gold layer, which broke off the protective layer. The corrosion rate was accelerated according to the big-cathode-small-anode model

  2. 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.…

  3. Evaluation of some essential elements levels in thalassemia patients in Mosul, Iraq

    International Nuclear Information System (INIS)

    Al-Samarrai, Abdulmunaim H.; Al-Tikriti, Khudhair A.; Al-Anzy, Muayed M.; Adaay, Mohaisen H.

    2008-01-01

    Objective was to evaluate the levels of some essential elements in thalassemic patients in Mousel, Iraq. One hundred and five thalassemic blood transfusion dependent children, 2.5-18 years of age attending Ibn-Al-Atheer teaching hospital in Mosul City, Iraq, during 2005, were used in this study. Fifty-four healthy subjects served as a control group. Patients were allocated in a non-randomized prospective cross-sectional hospital study. Essential elements levels were estimated. The mean, standard deviation, correction coefficient and z-test were used. P-values < 0.05 were considered statistically significant. Low serum Zinc, Magnesium, high serum copper and potassium levels were found among the 105 thalassemic patients compared to the 54 controls. Levels of calcium, phosphate and sodium were within normal limits. Fluctuations in the essential elements levels seem to be related to the different complications associated with the disease. Zinc deficiency may be attributed to hyperzincuria resulted from the release of Zn from hemolyzed red cells. Hypercupremia occurs in acute and chronic infections and hemochromatosis, which is a principal complication of thalassemia. Increased Na levels may be due to renal damage. Hypomagnesemia may occur due to hypoparathyroidism. (author)

  4. The development of MESHNOTE code for radionuclide migration in the near field

    International Nuclear Information System (INIS)

    Wakasugi, Keiichiro; Makino, Hitoshi; Robinson, P.

    1999-12-01

    MESHNOTE code was developed to evaluate the engineered barrier system in collaboration with QuantiSci. This code is used to simulate glass dissolution, diffusive transport of nuclides in the buffer material and release to surrounding host rock. MESHNOTE is a one-dimensional finite difference code, which uses cylindrical co-ordinates for the solution of a radially symmetric diffusion problem. MESHNOTE has the following characteristics: MESHNOTE can solve for diffusive transport of nuclides through an annulus shaped buffer region while accounting for multiple decay chains, linear and non-linear sorption onto the buffer materials and elemental solubility limits; MESHNOTE can solve for in growth of plural daughter nuclides from a singular parent nuclide (branching), and the ingrowth of a singular daughter nuclide from plural parent nuclides (rejoining); MESHNOTE can treat the leaching of nuclide from the vitrified waste and the release of nuclide from buffer to surrounding rock, which are boundary conditions for migration in the buffer, basing on the phenomena; MESHNOTE can treat principal parameters (e.g. solubility and distribution coefficient) relevant to nuclide migration as time and space-dependence parameters; The time stepping scheme in MESHNOTE is controlled by tolerance defined by the user. The time stepping will increase automatically while checking the accuracy of the numerical solution. The conceptual model, the mathematical model and the numerical implementation of the MESHNOTE code are described in this report and the characteristic functions of MESHNOTE are verified by comparing with analytical solutions or simulations produced with other calculation cedes. (author)

  5. 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.

  6. Climate change-related migration and infectious disease.

    Science.gov (United States)

    McMichael, Celia

    2015-01-01

    Anthropogenic climate change will have significant impacts on both human migration and population health, including infectious disease. It will amplify and alter migration pathways, and will contribute to the changing ecology and transmission dynamics of infectious disease. However there has been limited consideration of the intersections between migration and health in the context of a changing climate. This article argues that climate-change related migration - in conjunction with other drivers of migration - will contribute to changing profiles of infectious disease. It considers infectious disease risks for different climate-related migration pathways, including: forced displacement, slow-onset migration particularly to urban-poor areas, planned resettlement, and labor migration associated with climate change adaptation initiatives. Migration can reduce vulnerability to climate change, but it is critical to better understand and respond to health impacts - including infectious diseases - for migrant populations and host communities.

  7. [Environmental geochemical baseline of heavy metals in soils of the Ili river basin and pollution evaluation].

    Science.gov (United States)

    Zhao, Xin-Ru; Nasier, Telajin; Cheng, Yong-Yi; Zhan, Jiang-Yu; Yang, Jian-Hong

    2014-06-01

    Environmental geochemical baseline models of Cu, Zn, Pb, As, Hg were established by standardized method in the ehernozem, chestnut soil, sierozem and saline soil from the Ili river valley region. The theoretical baseline values were calculated. Baseline factor pollution index evaluation method, environmental background value evaluation method and heavy metal cleanliness evaluation method were used to compare soil pollution degrees. The baseline factor pollution index evaluation showed that As pollution was the most prominent among the four typical types of soils within the river basin, with 7.14%, 9.76%, 7.50% of sampling points in chernozem, chestnut soil and sierozem reached the heavy pollution, respectively. 7.32% of sampling points of chestnut soil reached the permitted heavy metal Pb pollution index in the chestnut soil. The variation extent of As and Pb was the largest, indicating large human disturbance. Environmental background value evaluation showed that As was the main pollution element, followed by Cu, Zn and Pb. Heavy metal cleanliness evaluation showed that Cu, Zn and Pb were better than cleanliness level 2 and Hg was the of cleanliness level 1 in all four types of soils. As showed moderate pollution in sierozem, and it was of cleanliness level 2 or better in chernozem, chestnut soil and saline-alkali soil. Comparing the three evaluation systems, the baseline factor pollution index evaluation more comprehensively reflected the geochemical migration characteristics of elements and the soil formation processes, and the pollution assessment could be specific to the sampling points. The environmental background value evaluation neglected the natural migration of heavy metals and the deposition process in the soil since it was established on the regional background values. The main purpose of the heavy metal cleanliness evaluation was to evaluate the safety degree of soil environment.

  8. Uncertainty evaluation in correlated quantities: application to elemental analysis of atmospheric aerosols;Evaluacion de la incertidumbre en cantidades correlacionadas: aplicacion al analisis elemental de aerosoles atmosfericos

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa, A.; Miranda, J.; Pineda, J. C., E-mail: miranda@fisica.unam.m [UNAM, Instituto de Fisica, Circuito de la Investigacion Cientifica s/n, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2010-07-01

    One of the aspects that are frequently overlooked in the evaluation of uncertainty in experimental data is the possibility that the involved quantities are correlated among them, due to different causes. An example in the elemental analysis of atmospheric aerosols using techniques like X-ray Fluorescence (X RF) or Particle Induced X-ray Emission (PIXE). In these cases, the measured elemental concentrations are highly correlated, and then are used to obtain information about other variables, such as the contribution from emitting sources related to soil, sulfate, non-soil potassium or organic matter. This work describes, as an example, the method required to evaluate the uncertainty in variables determined from correlated quantities from a set of atmospheric aerosol samples collected in the Metropolitan Area of the Mexico Valley and analyzed with PIXE. The work is based on the recommendations of the Guide for the Evaluation of Uncertainty published by the International Organization for Standardization. (Author)

  9. 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...

  10. 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....

  11. Utilization of radiographic and ultrasonic testing for an evaluation of plate type fuel elements during manufacturing stages

    International Nuclear Information System (INIS)

    Brito, Mucio Jose Drummond de; Silva Junior, Silverio Ferreira da; Messias, Jose Marcos; Braga, Daniel Martins; Paula, Joao Bosco de

    2005-01-01

    Structural discontinuities can be introduced in the plate type fuel elements during the manufacturing stages due to mechanical processing conditions. The use of nondestructive testing methods to monitoring the fuel elements during the manufacturing stages presents a significant importance, contributing for manufacturing process improvement and cost reducing. This paper describes a procedure to be used detection and evaluation of structural discontinuities in plate type fuel elements during the manufacturing stages using the ultrasonic testing method and the radiographic testing method. The main results obtained are presented and discussed. (author)

  12. Effect of several variables in the polymer toys additive migration to saliva.

    Science.gov (United States)

    Noguerol-Cal, R; López-Vilariño, J M; González-Rodríguez, M V; Barral-Losada, L

    2011-09-30

    Capacity to migrate of a representative group of polymeric additives, dyes, antioxidants, hindered amine light stabilizers (HALS) or antistatics, from plastic toys to saliva was analyzed to protect children in their habits of sucking and biting. Most of target additives appear no-regulated in toys normative but adverse effects on human health of some of them have been demonstrated and their presence in others commercial articles normative has been included. In order to offer an effective and easy tool to perform these controls, migration tests by dynamic and static contact, followed by a preconcentration step by liquid-liquid extraction (LLE) and ultra performance liquid chromatographic analysis with ultraviolet-visible and evaporative light scattering detections (UPLC-UV/Vis-ELSD) have been optimized to evaluate the migrated amounts of the additives in saliva simulant. The detection limits of the migration methodologies were ranged from 8.68 × 10(-2) to 1.30 × 10(-3)mg migrated (L simulant)(-1). Influence of several variables on this mass transport, as time, temperature and friction, was also analyzed to achieve the most aggressive methodology to protect consumers. Migration of several studied additives, whose presence has been demonstrated in several purchased commercial toys, has been observed. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Dynamic Quantification of Host Schwann Cell Migration into Peripheral Nerve Allografts

    Science.gov (United States)

    Whitlock, Elizabeth L.; Myckatyn, Terence M.; Tong, Alice Y.; Yee, Andrew; Yan, Ying; Magill, Christina K.; Johnson, Philip J.; Mackinnon, Susan E.

    2010-01-01

    Host Schwann cell (SC) migration into nerve allografts is the limiting factor in the duration of immunosuppression following peripheral nerve allotransplantation, and may be affected by different immunosuppressive regimens. Our objective was to compare SC migration patterns between clinical and experimental immunosuppression regimens both over time and at the harvest endpoint. Eighty mice that express GFP under the control of the Schwann cell specific S100 promoter were engrafted with allogeneic, nonfluorescent sciatic nerve grafts. Mice received immunosuppression with either tacrolimus (FK506), or experimental T-cell triple costimulation blockade (CSB), consisting of CTLA4-immunoglobulin fusion protein, anti-CD40 monoclonal antibody, and anti-inducible costimulator monoclonal antibody. Migration of GFP-expressing host SCs into wild-type allografts was assessed in vivo every 3 weeks until 15 weeks postoperatively, and explanted allografts were evaluated for immunohistochemical staining patterns to differentiate graft from host SCs. Immunosuppression with tacrolimus exhibited a plateau of SC migration, characterized by significant early migration (< 3 weeks) followed by a constant level of host SCs in the graft (15 weeks). At the endpoint, graft fluorescence was decreased relative to surrounding host nerve, and donor SCs persisted within the graft. CSB-treated mice displayed gradually increasing migration of host SCs into the graft, without the plateau noted in tacrolimus-treated mice, and also maintained a population of donor SCs at the 15-week endpoint. SC migration patterns are affected by immunosuppressant choice, particularly in the immediate postoperative period, and the use of a single treatment of CSB may allow for gradual population of nerve allografts with host SCs. PMID:20633557

  14. Work ability of Chinese migrant workers: the influence of migration characteristics.

    Science.gov (United States)

    Han, Lu; Shi, Leiyu; Lu, Liming; Ling, Li

    2014-04-13

    Migrant workers have become a vital labor supply to China's economy. Their migration process and work conditions may influence their health and work ability. The work ability of migrant workers in China and the influence of the migration process on work ability have not been explored extensively in previous studies. The objective of this study is to evaluate the association of migration characteristics and work-related factors with work ability among migrant workers in the Pearl River Delta. In this cross-sectional survey, the study population consisted of 907 migrant workers from ten factories in the Pearl River Delta who were exposed to organic solvents during work. The primary dependent variable of the study was work ability, measured by the Work Ability Index (WAI). The independent variables were individual characteristics, migration characteristics, and work-related factors. Logistic regression models were used to determine the influence of different factors on work ability and three dimensions of WAI. The result shows that among migration characteristics, social support was significantly associated with all three dimensions of the work ability index. Permanent migration intention and longer length of migration were negatively associated with the mental resource dimension of WAI. WAI was also influenced by individual and work-related factors. The findings of this study suggest that expanding migrants' social networks and social support systems in their work place or living community, (i.e. expanding the functions of labor unions) would be an effective way to improve migrant workers' work ability. Improving of migrant workers' physical and psychosocial related work environments would also increase their work ability.

  15. International labor migration and external debt.

    Science.gov (United States)

    Bustamante, J A

    1987-01-01

    The prevailing Mexican and US definitions of undocumented migration are poles apart. The US views it as a criminal problem. Mexicans view the undocumented migrants as actors in an economic game in which the rules are extremely disadvantageous to these migrants. Migrants themselves and their communities view the undocumented as a positive element. It is necessary to move toward a bilateral focus and bilateral negotiation on the issue of migratory workers. This proposal derives from several assumptions: 1) the external debt is a bilateral or multilateral issue, 2) it is important to avoid forcing debtor countries to choose between stimulating economic growth or making payment on their foreign debt, 3) prevailing public opinion in the US favors halting undocumented migration, 4) the US views the migration of undocumented Mexicans as the result of forces endogenous to Mexico and exogenous to the US, 5) the US views both Mexico's ability to make payment on its external debt and to halt emigration as tied to the Mexican government's ability or inability to reconcile political stability with scarce monetary resources, and 6) political instability in Mexico could augment emigration to the US and undermine Mexico's ability to address its foreign debt. The following proposal suggests means to link negotiation on the external debt to that of undocumented migration: 1) The Mexican government could reach an accord with the US to channel a portion of the actual interest on the external debt as a fund to be invested in Mexico to construct a system of labor intensive agroindustrial productive units designed to attract former or potential migratory workers; 2) the total amount of these funds would be deducted from interest payments on the principal of the actual external debt and redefined as an ad hoc loan to Mexico to finance these production units; 3) part of the production from these units would be incorporated into ongoing US food relief and food assistance programs; 4) the

  16. Pre-migration Trauma Exposure and Psychological Distress for Asian American Immigrants: Linking the Pre- and Post-migration Contexts.

    Science.gov (United States)

    Li, Miao; Anderson, James G

    2016-08-01

    Drawing on the life course perspective and the assumptive world theory, this paper examines whether pre-migration trauma exposure is associated with psychological distress through post-migration perceived discrimination for Asian American immigrants. The study is based on cross-sectional data from the National Latino and Asian American Study (N = 1639). Structural equation model is used to estimate the relationship between pre-migration trauma, post-migration perceived discrimination, and psychological distress. Additional models are estimated to explore possible variations across ethnic groups as well as across different types of pre-migration trauma experience. Pre-migration trauma exposure is associated with higher levels of psychological distress, both directly and indirectly through higher level of perceived discrimination, even after controlling for demographic/acculturative factors and post-migration trauma exposure. This pattern holds for the following sub-types of pre-migration trauma: political trauma, crime victimization, physical violence, accidental trauma, and relational trauma. Multi-group analyses show that this pattern holds for all Asian immigrant subgroups except the Vietnamese. Studies of immigrant mental health primarily focus on post-migration stressors. Few studies have considered the link between pre- and post-migration contexts in assessing mental health outcomes. The study illustrates the usefulness of bridging the pre- and post-migration context in identifying the mental health risks along the immigrant life course.

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

    International Nuclear Information System (INIS)

    Smith, C.L.

    1977-01-01

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

  18. 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...

  19. Migration energy barriers of symmetric tilt grain boundaries in body-centered cubic metal Fe

    International Nuclear Information System (INIS)

    Wu, Minghui; Gu, Jianfeng; Jin, Zhaohui

    2015-01-01

    Graphical abstract: DFT calculated migration energy barrier (left) for symmetric grain boundary in metals is an essential physical property to measure the trend of grain boundary migration, in particular, in terms of the classical homogeneous nucleation model of GB dislocation/disconnection loops (right). - Migration energy barriers of two symmetric tilt grain boundaries in body-centered cubic metal Fe are obtained via first-principles calculations in combination with the nudged elastic band methods. Although the two grain boundaries show similar grain boundary energies, the migration energy barriers are different. Based on a homogeneous nucleation theory of grain-boundary dislocation loops, the calculated energy barrier provides a measure of intrinsic grain-boundary mobility and helps to evaluate effects due to vacancy and interstitial atoms such as carbon

  20. 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.

  1. Survey-based Indicators of Regional Labour Markets and Interregional Migration in Norway

    OpenAIRE

    Carlsen, Fredrik; Johansen, Kåre

    2002-01-01

    A rich set of regional labour market variables is utilised to explain interregional migration in Norway. In particular, regional indicators of labour market pressure are computed from survey data in which respondents are asked to evaluate local job prospects in their resident municipality and the surroundings. Mean satisfaction with local job prospects reported by respondents in a region and related survey-based indicators have a positive and significant impact on net in-migration to the regi...

  2. The role of natural organics in radionuclide migration in natural aquifer systems

    International Nuclear Information System (INIS)

    Choppin, G.R.

    1992-01-01

    The wide variety of organic compounds present in natural waters is assessed for the role they may play in radionuclide and, especially, actinide migration. Some natural analog and environmental data are briefly reviewed for evaluation of the effect of organics in these systems. The binding constants and the kinetics of complexation of actinides by humics are discussed in terms of probable effects on actinide migration. The role of organics in redox, and in sorption, is also considered. (orig.)

  3. Narrow-front loop migration in a population of the common cuckoo Cuculus canorus, as revealed by satellite telemetry.

    Directory of Open Access Journals (Sweden)

    Mikkel Willemoes

    Full Text Available Narrow migration corridors known in diurnal, social migrants such as raptors, storks and geese are thought to be caused by topographical leading line effects in combination with learning detailed routes across generations. Here, we document narrow-front migration in a nocturnal, solitary migrant, the common cuckoo Cuculus canorus, using satellite telemetry. We tracked the migration of adult cuckoos from the breeding grounds in southern Scandinavia (n = 8, to wintering sites in south-western Central Africa (n = 6 and back to the breeding grounds (n = 3. Migration patterns were very complex; in addition to the breeding and wintering sites, six different stopover sites were identified during the 16,000 km annual route that formed a large-scale clockwise loop. Despite this complexity, individuals showed surprisingly similar migration patterns, with very little variation between routes. We compared observed tracks with simulated routes based on vector orientation (with and without effects of barriers on orientation and survival. Observed distances between routes were often significantly smaller than expected if the routes were established on the basis of an innate vector orientation programme. Average distance between individuals in eastern Sahel after having migrated more than 5,000 km for example, was merely 164 km. This implies that more sophisticated inherent guiding mechanisms, possibly involving elements of intermediate goal area navigation or more elaborate external cues, are necessary to explain the complex narrow-front migration pattern observed for the cuckoos in this study.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 99Tc, Pb and Ru migration around the Oklo natural fission reactors

    International Nuclear Information System (INIS)

    Gancarz, A.; Cowan, G.; Curtis, D.; Maeck, W.

    1980-01-01

    This work demonstrates the utility of the Oklo uranium ore deposit and natural fission reactors as a long time scale analogue for man-made radioactive waste repositories. It has been shown that the ores and nearby rocks were open to the loss and gain of 99 Tc, ruthenium, and lead relative to uranium. Identified regions of element deficiencies and those which are correspondingly enriched are separated by less than 10 meters. However, more extensive sampling is required to define the overall extent of the element migration. Element fractionation took place on at least two vastly different time scales; 99 Tc was fractionated from ruthenium within one million years of the end of reactor criticality. Lead-uranium fractionation has been ongoing for most of the two billion years since the ores were formed. Diffusion loss of lead from host uraninite appears to be an important process in the fractionation of lead from uranium

  9. 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

  10. Mir-513a-3p contributes to the controlling of cellular migration processes in the A549 lung tumor cells by modulating integrin β-8 expression.

    Science.gov (United States)

    da Silveira, Marina Bonfogo; Lima, Kelvin Furtado; da Silva, Andrea Renata; Dos Santos, Robson Augusto Souza; Moraes, Karen C M

    2017-12-04

    Lung tumors are a frequent type of cancer in humans and a leading cause of death, and the late diagnostic contributes to high mortality rates. New therapeutic strategies are needed, and the heptapeptide angiotensin-(1-7) [ang-(1-7)] demonstrated the ability to control cancer growth rates and migration in vitro and in vivo. However, the possible use of the heptapeptide in clinical trials demands deeper analyses to elucidate molecular mechanisms of its effect in the target cells. In this study, we investigated relevant elements that control pro-inflammatory environment and cellular migration, focusing in the post-transcription mechanism using lung tumor cell line. In our cellular model, the microRNA-513a-3p was identified as a novel element targeting ITG-β8, thereby controlling the protein level and its molecular function in the controlling of migration and pro-inflammatory environment. These findings provide useful information for future studies, using miR-513a-3p as an innovative molecular tool to control lung tumor cell migration, which will support more effective clinical treatment of the patients with the widely used chemotherapeutic agents, increasing survival rates.

  11. IUSSP Committee on International Migration, Workshop on International Migration Systems and Networks.

    Science.gov (United States)

    Lim, Lin Lean

    1987-01-01

    This mini-workshop sought a framework for examining the dynamics of migration processes, especially the interlinkages between sending and receiving countries. These two focuses emerged as directions for further research: (1) a topology reflecting the concepts underlying international migration; and (2) empirical studies which attempt to apply the…

  12. 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.

  13. Experimental Behavior Evaluation of Series and Parallel Connected Constant Phase Elements

    KAUST Repository

    Tsirimokou, Georgia

    2017-01-28

    Fractional-order capacitors are the core building blocks for implementing fractional-order circuits. Due to the absence of their commercial availability, they can be approximated through appropriately configured passive or active integer-order element topologies. Such a topology, constructed using Operational Transconductance Amplifiers (OTAs) and capacitors has been implemented in monolithic form through the AMS 0.35μm CMOS process, and the fabricated chips are employed here for the experimental evaluation of the behavior of networks constructed from fractional-order capacitors connected in series or in parallel.

  14. Transnational Solidarity—Not Aid: The Perspective of Migration on the Hype about Migration&Development

    Directory of Open Access Journals (Sweden)

    Maria Schwertl

    2017-09-01

    Full Text Available Migrants have organized transnational support for non-migrants, stay-at-homes, citizens and noncitizens, as well as for developmental or integrationist nation state projects for decades. These solidarities have been framed as “cultural programs,” “autochthone support of hometowns,” “development aid” or “diaspora politics.” Since the turn of the century especially those projects that could be framed as “development aid” have gained a lot of interest from official development aid and its agencies. More and more programs have been launched to coordinate and professionalize the transnational support labor of migrants under the aegis of development. This is what I call the hype about migration&development. In this article, I want to show why the notion of “migrant development aid” used in the hype falls short of what is at stake when it comes to transnational migrant solidarities. Thereby, I want to argue that looking at migration through its governance and through migration or development politics is short-sighted and insensitive towards the desires, ethics and politics of migration. This is the reason that a perspective of migration—such as that propagated by the autonomy of migration approach—needs to be brought into debates on migration&development.

  15. Modeling and predictions of biphasic mechanosensitive cell migration altered by cell-intrinsic properties and matrix confinement.

    Science.gov (United States)

    Pathak, Amit

    2018-04-12

    Motile cells sense the stiffness of their extracellular matrix (ECM) through adhesions and respond by modulating the generated forces, which in turn lead to varying mechanosensitive migration phenotypes. Through modeling and experiments, cell migration speed is known to vary with matrix stiffness in a biphasic manner, with optimal motility at an intermediate stiffness. Here, we present a two-dimensional cell model defined by nodes and elements, integrated with subcellular modeling components corresponding to mechanotransductive adhesion formation, force generation, protrusions and node displacement. On 2D matrices, our calculations reproduce the classic biphasic dependence of migration speed on matrix stiffness and predict that cell types with higher force-generating ability do not slow down on very stiff matrices, thus disabling the biphasic response. We also predict that cell types defined by lower number of total receptors require stiffer matrices for optimal motility, which also limits the biphasic response. For a cell type with robust biphasic migration on 2D surface, simulations in channel-like confined environments of varying width and height predict faster migration in more confined matrices. Simulations performed in shallower channels predict that the biphasic mechanosensitive cell migration response is more robust on 2D micro-patterns as compared to the channel-like 3D confinement. Thus, variations in the dimensionality of matrix confinement alters the way migratory cells sense and respond to the matrix stiffness. Our calculations reveal new phenotypes of stiffness- and topography-sensitive cell migration that critically depend on both cell-intrinsic and matrix properties. These predictions may inform our understanding of various mechanosensitive modes of cell motility that could enable tumor invasion through topographically heterogeneous microenvironments. © 2018 IOP Publishing Ltd.

  16. IS WAGE A MANAGERIAL MOTIVATIONAL TOOL OR A MIGRATION DETERMINANT AMONG YOUNG PEOPLE?

    Directory of Open Access Journals (Sweden)

    MANCIU VENERA CRISTINA

    2014-08-01

    Full Text Available In recent years, the phenomenon of migration has intensified throughout the country, an increasing number of people choosing the path of foreign countries in the hope of a better life. It becomes a challenge for general managers in firms to retain those employees who have the skills needed to perform at a high level of performance the duties regarding work. The research conducted in this paper is a qualitative one, trying to provide an answer to the question stated in the title, ie if the current salary level practiced in Romania is a motivational factor for providing a valuable work, or on the contrary, is an element that lies at the basis of migration. The first part of the paper presents a theoretical point of view, presenting general aspects regarding the current economic context in terms of staff motivation, but also the general perspectives referring to the issue of migration. The final part presents a study that uses the focus group method in order to determine whether the young people in Caras Severin are susceptible to leaving the country for a higher wage level or would they consider this aspect for the following period of time.

  17. Migration of plasma points in the Z-pinch

    International Nuclear Information System (INIS)

    Afonin, V.I.

    1995-01-01

    The paper deals with the generation of a spontaneous magnetic field in Z-pinch sausage-type instability plasma and the effect of magnetic field on sausage-type instability movement. The presented evaluations of spontaneous magnetic fields and their role in the migration of plasma points are in a satisfactory agreement with the experimental data. 8 refs

  18. Dynamic Migration Intentions and the Impact of Socio-Institutional Environments: A Transit Migration Hub in Turkey

    NARCIS (Netherlands)

    Wissink, M.J.; Düvell, F.; van Eerdewijk, A.

    2013-01-01

    Transit migration is generally defined by migrants having the intention to move onwards to a third country. Based on an empirical investigation in Izmir, a transit migration hub in Turkey, this paper critically discusses intentionality as a valid dimension in conceptualisations of transit migration.

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

    Directory of Open Access Journals (Sweden)

    Mohite Prashant N

    2013-01-01

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

  20. CT and MR imaging evaluation of the inherited and prenatally acquired migrational disorders of the brain

    International Nuclear Information System (INIS)

    Byrd, S.E.; Osborn, R.E.; Naidich, T.P.; Bohan, T.P.

    1987-01-01

    The migrational disorders are a rare group of congenital malformations of the brain seen in children. They are primarily cortical and gray matter abnormalities. Forty patients, divided into two groups, were studied. In one group were patients with the classic migrational lesions of lissencephaly, pachygyria, schizencephaly, heterotopia, and polymicrogyria in which the underlying cause is genetic, chromosomal, or unknown. In the second group were patients with lesions caused by a prenatally acquired infection (toxoplasmosis or cytomegalic virus) or a metabolic abnormality. The CT and MR imaging findings in these two groups are discussed

  1. Return Migration as Failure or Success?: The Determinants of Return Migration Intentions Among Moroccan Migrants in Europe.

    Science.gov (United States)

    de Haas, Hein; Fokkema, Tineke; Fihri, Mohamed Fassi

    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 migrants have earned sufficient assets and knowledge and to invest in their origin countries. The projected return is then likely to be postponed for sustained or indefinite periods if integration is unsuccessful. So, from an indication or result of integration failure return is rather seen as a measure of success. Drawing on recent survey data ( N  = 2,832), this article tests these hypotheses by examining the main determinants of return intention among Moroccan migrants across Europe. The results indicate that structural integration through labour market participation, education and the maintenance of economic and social ties with receiving countries do not significantly affect return intentions. At the same time, investments and social ties to Morocco are positively related, and socio-cultural integration in receiving countries is negatively related to return migration intentions. The mixed results corroborate the idea that there is no uniform process of (return) migration and that competing theories might therefore be partly complementary.

  2. A new fully covered metal stent with anti-migration features for the treatment of malignant dysphagia

    NARCIS (Netherlands)

    Walter, Daisy; van den Berg, Maarten W.; van Hooft, Jeanin E.; Boot, Henk; Scheffer, Robert C. H.; Vleggaar, Frank P.; Siersema, Peter D.

    2014-01-01

    A new esophageal stent with two anti-migration features was developed to minimize migration. The aim of this study was to evaluate the clinical efficacy and safety of this stent in patients with malignant dysphagia. A total of 40 patients with dysphagia due to a malignant obstruction of the

  3. A Study on the Nuclide Migration and Retardation Using Natural Barrier

    International Nuclear Information System (INIS)

    Baik, Min Hoon; Park, Chung Kyun; Kim, Seung Soo

    2010-02-01

    In this study, we investigated the properties of geochemical reactions and sorption of high-level radionuclides (U, Th, Am, and Np), constructed databases for the geochemical reactions and sorption of the high-level radionuclides, and developed application methodologies of the databases. For the investigation on the nuclide migration and retardation through fractured rocks in KURT, in-situ solute migration system and on-line monitoring system were installed. The migration and retardation behaviors of nuclides were investigated annually for non-sorbing, simply sorbing and multi-valent sorbing nuclides, respectively, and interactions with fracture-filling materials were also analyzed. Besides, researches difficult to perform in KURT were carried out in foreign underground research facilities as joint studies for nuclide and colloid migration. The results from domestic and foreign underground facilities were compared each other and the reliability of the domestic results were assured from this. Diffusion depths of high-level radionuclides into rock matrix were measured in KURT conditions and their diffusion properties were analyzed and evaluated. In addition, the effects of bio-mineralization and redox reactions of a nuclide and microbe on nuclide behaviors were carried out to study the effects of combined interactions between minerals and microbes on the radionuclide migration and retardation

  4. 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)

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

    Science.gov (United States)

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

    2011-04-01

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

  6. Weather conditions associated with autumn migration by mule deer in Wyoming

    Directory of Open Access Journals (Sweden)

    Chadwick D. Rittenhouse

    2015-06-01

    Full Text Available Maintaining ecological integrity necessitates a proactive approach of identifying and acquiring lands to conserve unfragmented landscapes, as well as evaluating existing mitigation strategies to increase connectivity in fragmented landscapes. The increased use of highway underpasses and overpasses to restore connectivity for wildlife species offers clear conservation benefits, yet also presents a unique opportunity to understand how weather conditions may impact movement of wildlife species. We used remote camera observations (19,480 from an existing wildlife highway underpass in Wyoming and daily meteorological observations to quantify weather conditions associated with autumn migration of mule deer in 2009 and 2010. We identified minimal daily temperature and snow depth as proximate cues associated with mule deer migration to winter range. These weather cues were consistent across does and bucks, but differed slightly by year. Additionally, extreme early season snow depth or cold temperature events appear to be associated with onset of migration. This information will assist wildlife managers and transportation officials as they plan future projects to maintain and enhance migration routes for mule deer.

  7. INTERNATIONAL MIGRATION AND THE EDUCATION OF CHILDREN: EVIDENCE FROM LIMA, PERU.

    Science.gov (United States)

    Robles, Verónica Frisancho; Oropesa, R S

    2011-08-01

    The issue of whether emigration has consequences for the education of children who remain behind in the country of origin occupies an increasingly prominent place in the agendas of both scholars and policy makers. The conventional wisdom is that the emigration of family members may benefit children by relaxing budget constraints through remittances that can be used to cover educational expenses. However, the empirical evidence on the overall effect of migration is inconclusive. This is due in part to a substantive emphasis on remittances in the literature, as well as the inability of some studies to deal satisfactorily with the endogeneity of household migration decisions in comparing outcomes across migrant and non-migrant households. Using Peruvian data from the Latin American Migration Project (LAMP), we apply an innovative instrumental variable technique to evaluate the overall effect of migration on educational attainment and schooling disruption among the children of immigrants. In contrast to conventional wisdom, our results suggest that a higher household risk of immigration has deleterious consequences for the education of children who remain behind.

  8. INTERNATIONAL MIGRATION AND THE EDUCATION OF CHILDREN: EVIDENCE FROM LIMA, PERU

    Science.gov (United States)

    Robles, Verónica Frisancho; Oropesa, R.S.

    2012-01-01

    The issue of whether emigration has consequences for the education of children who remain behind in the country of origin occupies an increasingly prominent place in the agendas of both scholars and policy makers. The conventional wisdom is that the emigration of family members may benefit children by relaxing budget constraints through remittances that can be used to cover educational expenses. However, the empirical evidence on the overall effect of migration is inconclusive. This is due in part to a substantive emphasis on remittances in the literature, as well as the inability of some studies to deal satisfactorily with the endogeneity of household migration decisions in comparing outcomes across migrant and non-migrant households. Using Peruvian data from the Latin American Migration Project (LAMP), we apply an innovative instrumental variable technique to evaluate the overall effect of migration on educational attainment and schooling disruption among the children of immigrants. In contrast to conventional wisdom, our results suggest that a higher household risk of immigration has deleterious consequences for the education of children who remain behind. PMID:22581990

  9. The health impacts of climate-related migration.

    Science.gov (United States)

    Schwerdtle, Patricia; Bowen, Kathryn; McMichael, Celia

    2017-12-11

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

  10. 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

  11. Andrographolide reduces proliferation and migration of lens epithelial cells by modulating PI3K/Akt pathway.

    Science.gov (United States)

    Kayastha, Forum; Madhu, Hardik; Vasavada, Abhay; Johar, Kaid

    2014-11-01

    Lens epithelial cell proliferation, migration, and transdifferentiation are involved in the development of subcapsular cataracts and postoperative capsular opacification (PCO). PI3K/Akt pathway is involved in the proliferation and migration of lens epithelial cells. Andrographolide is the main bioactive component of Andrographis paniculata and is known to possess anti-proliferative and anti-migratory activities. The purpose of this study is to evaluate the effect of andrographolide on proliferation and migration induced by growth factors (TGF-β and bFGF) in the lens epithelial cell line, FHL 124. We have also evaluated the role of the PI3K/Akt pathway and its alteration by andrographolide during proliferation and migration of lens epithelial cells. The results showed that andrographolide significantly inhibited proliferation in a dose and time dependent manner. The growth factors, TGF-β and bFGF, induced migration of lens epithelial cells, which was lowered by andrographolide. The growth factors also up regulated phosphorylated Akt (Ser473) and Akt (Thr308), which was abolished by simultaneous treatment of andrographolide. Similar changes were also observed with the PI3K inhibitor, LY290042. Our findings suggest that andrographolide reduces proliferation, migration, and phosphorylated Akt levels in lens epithelial cells. Hence andrographolide can be utilized for the prevention of PCO. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. U.S. backs "well-being" programs for women. An interview with Julia Taft, Assistant Secretary of State for Population, Refugees and Migration.

    Science.gov (United States)

    Scherr, E F

    1998-09-01

    This interview with Julia Taft, Assistant Secretary of State for Population, Refugees and Migration concerns a wide range of well-being programs for women in the US. The ICPD Program of Action considers family planning and reproductive health in the broader contexts of women's empowerment, girls¿ and boys' education, child health, and social elements (among them economic and environmental elements), that affect the lives of girls and women. US programs and policies encompass the promotion of the whole range of well-being of women and girls, of which family planning and reproductive health are key elements. Congress has passed a law ensuring complete access to reproductive health care services by making it a crime to use force or to interfere with reproductive health providers or their patients. There was also a recent decision to require federal employees' health insurance plans to cover contraceptives. The US supports several international organizations working on population issues such as UNFPA, UNICEF, UNAIDS, WHO, and UNDP. The UN will continually have to evaluate its progress so that in 15 years human rights, civil rights, and proper health care will have been extended to the entire world.

  13. Dietary patterns and trace elements intake evaluation

    International Nuclear Information System (INIS)

    Rahman, A.; Waheed, S.; Zaidi, J.H.; Ahmad, S.

    1998-01-01

    The dietary patterns and trace element contents of the integrated diets of middle income population in Gujranwala and of Islamabad have been studied and dietary intake of winter and summer are given. An overview of the elemental concentration in the two sets of integrated diets reveals similar zinc and manganese concentrations; comparatively higher nickel, selenium and potassium concentrations in Gujranwala and higher chromium, cesium, scandium, sodium and chlorine concentrations in Islamabad. These results undoubtedly reflect the difference in food selection and habits of the two populations, the influence of soil content and industrial pollution

  14. Length of migration and eating habits of Portuguese university students living in London, United Kingdom.

    Science.gov (United States)

    Vilela, Sofia; Santos, Susana; Padrão, Patrícia; Caraher, Martin

    2014-01-01

    Several studies have pointed adverse effects of long term migration on eating habits. Research is needed to understand if this effect occurs also with a short length of migration, as is the case of international students. Our aim was to evaluate the effect of short and long term migration on eating habits of Portuguese university students. Participants were 46 English and 55 Portuguese students from universities in London, United Kingdom. The findings from this study highlight the difficulties that Portuguese students faced in maintaining a traditional Mediterranean diet after moving to a Northern European environment.

  15. Current-induced changes of migration energy barriers in graphene and carbon nanotubes.

    Science.gov (United States)

    Obodo, J T; Rungger, I; Sanvito, S; Schwingenschlögl, U

    2016-05-21

    An electron current can move atoms in a nanoscale device with important consequences for the device operation and breakdown. We perform first principles calculations aimed at evaluating the possibility of changing the energy barriers for atom migration in carbon-based systems. In particular, we consider the migration of adatoms and defects in graphene and carbon nanotubes. Although the current-induced forces are large for both the systems, in graphene the force component along the migration path is small and therefore the barrier height is little affected by the current flow. In contrast, the same barrier is significantly reduced in carbon nanotubes as the current increases. Our work also provides a real-system numerical demonstration that current-induced forces within density functional theory are non-conservative.

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

    Directory of Open Access Journals (Sweden)

    Marta-Christina Suciu

    2017-08-01

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

  17. 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.

  18. High glucose-mediated oxidative stress impairs cell migration.

    Directory of Open Access Journals (Sweden)

    Marcelo L Lamers

    Full Text Available Deficient wound healing in diabetic patients is very frequent, but the cellular and molecular causes are poorly defined. In this study, we evaluate the hypothesis that high glucose concentrations inhibit cell migration. Using CHO.K1 cells, NIH-3T3 fibroblasts, mouse embryonic fibroblasts and primary skin fibroblasts from control and diabetic rats cultured in 5 mM D-glucose (low glucose, LG, 25 mM D-glucose (high glucose, HG or 25 mM L-glucose medium (osmotic control--OC, we analyzed the migration speed, protrusion stability, cell polarity, adhesion maturation and the activity of the small Rho GTPase Rac1. We also analyzed the effects of reactive oxygen species by incubating cells with the antioxidant N-Acetyl-Cysteine (NAC. We observed that HG conditions inhibited cell migration when compared to LG or OC. This inhibition resulted from impaired cell polarity, protrusion destabilization and inhibition of adhesion maturation. Conversely, Rac1 activity, which promotes protrusion and blocks adhesion maturation, was increased in HG conditions, thus providing a mechanistic basis for the HG phenotype. Most of the HG effects were partially or completely rescued by treatment with NAC. These findings demonstrate that HG impairs cell migration due to an increase in oxidative stress that causes polarity loss, deficient adhesion and protrusion. These alterations arise, in large part, from increased Rac1 activity and may contribute to the poor wound healing observed in diabetic patients.

  19. Understanding the microscopic moisture migration in pore space using DEM simulation

    Directory of Open Access Journals (Sweden)

    Yuan Guo

    2015-04-01

    Full Text Available The deformation of soil skeleton and migration of pore fluid are the major factors relevant to the triggering of and damages by liquefaction. The influence of pore fluid migration during earthquake has been demonstrated from recent model experiments and field case studies. Most of the current liquefaction assessment models are based on testing of isotropic liquefiable materials. However the recent New Zealand earthquake shows much severer damages than those predicted by existing models. A fundamental cause has been contributed to the embedded layers of low permeability silts. The existence of these silt layers inhibits water migration under seismic loads, which accelerated liquefaction and caused a much larger settlement than that predicted by existing theories. This study intends to understand the process of moisture migration in the pore space of sand using discrete element method (DEM simulation. Simulations were conducted on consolidated undrained triaxial testing of sand where a cylinder sample of sand was built and subjected to a constant confining pressure and axial loading. The porosity distribution was monitored during the axial loading process. The spatial distribution of porosity change was determined, which had a direct relationship with the distribution of excess pore water pressure. The non-uniform distribution of excess pore water pressure causes moisture migration. From this, the migration of pore water during the loading process can be estimated. The results of DEM simulation show a few important observations: (1 External forces are mainly carried and transmitted by the particle chains of the soil sample; (2 Porosity distribution during loading is not uniform due to non-homogeneous soil fabric (i.e. the initial particle arrangement and existence of particle chains; (3 Excess pore water pressure develops differently at different loading stages. At the early stage of loading, zones with a high initial porosity feature higher

  20. 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

  1. 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...

  2. Effect of nordihydroguaiaretic acid cross-linking on fibrillar collagen: in vitro evaluation of fibroblast adhesion strength and migration

    Directory of Open Access Journals (Sweden)

    Ana Y. Rioja

    2017-04-01

    Full Text Available Fixation is required to reinforce reconstituted collagen for orthopedic bioprostheses such as tendon or ligament replacements. Previous studies have demonstrated that collagen fibers cross-linked by the biocompatible dicatechol nordihydroguaiaretic acid (NDGA have mechanical strength comparable to native tendons. This work focuses on investigating fibroblast behavior on fibrillar and NDGA cross-linked type I collagen to determine if NDGA modulates cell adhesion, morphology, and migration. A spinning disk device that applies a range of hydrodynamic forces under uniform chemical conditions was employed to sensitively quantify cell adhesion strength, and a radial barrier removal assay was used to measure cell migration on films suitable for these quantitative in vitro assays. The compaction of collagen films, mediated by the drying and cross-linking fabrication process, suggests a less open organization compared to native fibrillar collagen that likely allowed the collagen to form more inter-chain bonds and chemical links with NDGA polymers. Fibroblasts strongly adhered to and migrated on native and NDGA cross-linked fibrillar collagen; however, NDGA modestly reduced cell spreading, adhesion strength and migration rate. Thus, it is hypothesized that NDGA cross-linking masked some adhesion receptor binding sites either physically, chemically, or both, thereby modulating adhesion and migration. This alteration in the cell-material interface is considered a minimal trade-off for the superior mechanical and compatibility properties of NDGA cross-linked collagen compared to other fixation approaches.

  3. Effects of salinity on trace elements in otoliths of Masu salmon

    International Nuclear Information System (INIS)

    Nagata, Yoshihisa; Arai, Nobuaki; Sakamoto, Wataru; Tago, Yasuhiko; Yoshida, Koji

    1997-01-01

    PIXE was adopted for analysis of trace elements in otoliths of Masu salmon Oncorhynchus masou masou to examine relationship between trace elements and environmental salinity. The otoliths were removed from salmon juveniles reared in four values of salinity and wild ones. The otolith Sr concentrations of reared individuals are positively related to salinity and there is significant difference between freshwater and seawater. The otoliths of smolts contain more Sr than those of parrs. It seems that the Sr concentrations in otoliths of Masu salmon reflect salinity where they had stayed and show the migration pattern. (author)

  4. 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.

  5. Reversed-phase thin-layer chromatography of the rare earth elements

    International Nuclear Information System (INIS)

    Kuroda, R.; Adachi, M.; Oguma, K.

    1988-01-01

    Partition chromatographic behaviour of the rare earth elements on C 18 bonded silica reversed-phase material has been investigated by thin-layer chromatography in methanol - lactate media. The rare earth lactato complexes are distributed and fractionated on bonded silica layers without ion-interaction reagents. The concentration and pH of lactate solution, methanol concentration and temperature have effects on the migration and resolution of the rare earth elements. The partition system is particularly suited to separate adjacent rare earths of middle atomic weight groups, allowing the separation of gadolinium, terbium, dysprosium, holmium, erbium and thulium to be achieved by development to 18 cm distance. (orig.)

  6. Migrants' dreams and planners' nightmares: international labour migration in the Arab world and the growth of two sets of cities.

    Science.gov (United States)

    Findlay, A M

    1985-11-01

    "The author investigates how trends in international labour migration in the Arab world have been paralleled by new directions in migration research....[She] seeks to evaluate why the urban impact of international migration is so great and outlines the considerable potential which exists for pursuing research on this aspect of urban development." excerpt

  7. 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.

  8. Individual versus Household Migration Decision Rules: Gender and Marital Status Differences in Intentions to Migrate in South Africa.

    Science.gov (United States)

    Gubhaju, Bina; De Jong, Gordon F

    2009-03-01

    This research tests the thesis that the neoclassical micro-economic and the new household economic theoretical assumptions on migration decision-making rules are segmented by gender, marital status, and time frame of intention to migrate. Comparative tests of both theories within the same study design are relatively rare. Utilizing data from the Causes of Migration in South Africa national migration survey, we analyze how individually held "own-future" versus alternative "household well-being" migration decision rules effect the intentions to migrate of male and female adults in South Africa. Results from the gender and marital status specific logistic regressions models show consistent support for the different gender-marital status decision rule thesis. Specifically, the "maximizing one's own future" neoclassical microeconomic theory proposition is more applicable for never married men and women, the "maximizing household income" proposition for married men with short-term migration intentions, and the "reduce household risk" proposition for longer time horizon migration intentions of married men and women. Results provide new evidence on the way household strategies and individual goals jointly affect intentions to move or stay.

  9. 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.

  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. Dancing Styles of Collective Cell Migration: Image-Based Computational Analysis of JRAB/MICAL-L2.

    Science.gov (United States)

    Sakane, Ayuko; Yoshizawa, Shin; Yokota, Hideo; Sasaki, Takuya

    2018-01-01

    Collective cell migration is observed during morphogenesis, angiogenesis, and wound healing, and this type of cell migration also contributes to efficient metastasis in some kinds of cancers. Because collectively migrating cells are much better organized than a random assemblage of individual cells, there seems to be a kind of order in migrating clusters. Extensive research has identified a large number of molecules involved in collective cell migration, and these factors have been analyzed using dramatic advances in imaging technology. To date, however, it remains unclear how myriad cells are integrated as a single unit. Recently, we observed unbalanced collective cell migrations that can be likened to either precision dancing or awa-odori , Japanese traditional dancing similar to the style at Rio Carnival, caused by the impairment of the conformational change of JRAB/MICAL-L2. This review begins with a brief history of image-based computational analyses on cell migration, explains why quantitative analysis of the stylization of collective cell behavior is difficult, and finally introduces our recent work on JRAB/MICAL-L2 as a successful example of the multidisciplinary approach combining cell biology, live imaging, and computational biology. In combination, these methods have enabled quantitative evaluations of the "dancing style" of collective cell migration.

  12. 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

  13. 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.

  14. Tunneling and migration of the dumbbell defect in electron-irradiated aluminum-zinc alloys

    International Nuclear Information System (INIS)

    Wallace, P.W.

    1983-01-01

    Ultrasonic attenuation and velocity measurements on irradiated Al-Zn alloys (0.01, 0.1, and 0.5 at %) indicate a tunneling relaxation of the predominant mixed dumbbell defect at low temperatures, and mixed dumbbell migration at the Stage II anneal temperature. The effect of an internal strain varying with the zinc concentration on the measured decrement and modulus change is striking. Evaluated in the framework of a six-level system, this reveals the simultaneous action of resonance and nonclassical relaxation processes. Using Fe as a probe atom, it is shown that mixed dumbbell dissociation is in an insignificant component of the annealing of this defect. The decrease of the annealing temperature at higher zinc concentrations provides evidence that the mixed dumbbell migrates as a unit during annealing. The energies associated with dumbbell migration and interstitial escape are derived. Further evidence for the migration mechanism is obtained from successive irradiation and annealing

  15. Scheduling in Heterogeneous Grid Environments: The Effects of DataMigration

    Energy Technology Data Exchange (ETDEWEB)

    Oliker, Leonid; Biswas, Rupak; Shan, Hongzhang; Smith, Warren

    2004-01-01

    Computational grids have the potential for solving large-scale scientific problems using heterogeneous and geographically distributed resources. However, a number of major technical hurdles must be overcome before this goal can be fully realized. One problem critical to the effective utilization of computational grids is efficient job scheduling. Our prior work addressed this challenge by defining a grid scheduling architecture and several job migration strategies. The focus of this study is to explore the impact of data migration under a variety of demanding grid conditions. We evaluate our grid scheduling algorithms by simulating compute servers, various groupings of servers into sites, and inter-server networks, using real workloads obtained from leading supercomputing centers. Several key performance metrics are used to compare the behavior of our algorithms against reference local and centralized scheduling schemes. Results show the tremendous benefits of grid scheduling, even in the presence of input/output data migration - while highlighting the importance of utilizing communication-aware scheduling schemes.

  16. Household ecology and out-migration among ethnic Karen along the Thai-Myanmar border

    Directory of Open Access Journals (Sweden)

    Daniel M. Parker

    2014-04-01

    Full Text Available Background: Local migration in developing-world settings, particularly among rural populations, is an important yet understudied demographic process. Research on migration in such populations can help us test and inform anthropological and demographic theory. Furthermore, it can lead to a better understanding of modern population distributions and epidemiologic landscapes. Objective: The purpose of this study was to investigate the potential relationships between household- and individual-level factors on out-migration among Karen villagers along the Thai-Myanmar border. Methods: We used a random effects hazard model to investigate the relationship of household consumer-producer (C/P ratios, the number of household members, and an individual's sex on the odds of outmigration. We then used simulations in order to test the sensitivity of our model to our C/P ratio weighting scheme. Results: We found that the number of household members is predictive of increased out-migration. Household C/P ratios were positively associated with out-migration in children but negatively associated with out-migration in working age adults. Finally, adult males were much more likely to move out of the household than were adult females. Conclusions: While household-level factors are important with regard to out-migration, the relationships between such household-level factors and out-migration are complex and vary by the individual's age and sex. Our study offers two novel concepts to household demography and migration studies. First, this study offers a new approach to evaluating weighting schemes for C/P ratios. Second, we show that household level factors are important at units of time (two-week intervals that are not normally studied by demographers.

  17. Examining speed versus selection in connectivity models using elk migration as an example

    Science.gov (United States)

    Brennan, Angela; Hanks, Ephraim M.; Merkle, Jerod A.; Cole, Eric K.; Dewey, Sarah R.; Courtemanch, Alyson B.; Cross, Paul C.

    2018-01-01

    ContextLandscape resistance is vital to connectivity modeling and frequently derived from resource selection functions (RSFs). RSFs estimate relative probability of use and tend to focus on understanding habitat preferences during slow, routine animal movements (e.g., foraging). Dispersal and migration, however, can produce rarer, faster movements, in which case models of movement speed rather than resource selection may be more realistic for identifying habitats that facilitate connectivity.ObjectiveTo compare two connectivity modeling approaches applied to resistance estimated from models of movement rate and resource selection.MethodsUsing movement data from migrating elk, we evaluated continuous time Markov chain (CTMC) and movement-based RSF models (i.e., step selection functions [SSFs]). We applied circuit theory and shortest random path (SRP) algorithms to CTMC, SSF and null (i.e., flat) resistance surfaces to predict corridors between elk seasonal ranges. We evaluated prediction accuracy by comparing model predictions to empirical elk movements.ResultsAll connectivity models predicted elk movements well, but models applied to CTMC resistance were more accurate than models applied to SSF and null resistance. Circuit theory models were more accurate on average than SRP models.ConclusionsCTMC can be more realistic than SSFs for estimating resistance for fast movements, though SSFs may demonstrate some predictive ability when animals also move slowly through corridors (e.g., stopover use during migration). High null model accuracy suggests seasonal range data may also be critical for predicting direct migration routes. For animals that migrate or disperse across large landscapes, we recommend incorporating CTMC into the connectivity modeling toolkit.

  18. Plasma rich in growth factors promotes dermal fibroblast proliferation, migration and biosynthetic activity.

    Science.gov (United States)

    Anitua, E; Pino, A; Orive, G

    2016-11-02

    The use of plasma rich in growth factors (PRGF) has gained importance in many medical fields due to its regenerative potential. The aim of this study is to evaluate the effects of PRGF on primary skin fibroblasts assessing cell proliferation, migration and secretion of growth factors. The age of the patients from who PRGF was prepared was also studied to determine whether it influenced the outcomes. Human dermal fibroblasts were isolated from three healthy volunteers. Using PRGF-Endoret technology, PRGF was prepared from two groups of different ages (18-35 years and 50+ years). The effects of increasing concentration of PRGF (5%, 10% and 20%) on cell proliferation and migration was evaluated. Biosynthetic behaviour of cells was also analysed measuring vascular endothelial growth factor (VEGF), transforming growth factor b1 (TGFb1) and pro-collagen type I secreted levels with or without PRGF treatment. Mean platelet enrichment reached 2.4X and 2X in 18-35 and 50+ groups respectively. A dose-dependent response was observed in proliferation assays achieving the highest levels with 20% PRGF. Migration was also promoted in cells but not in a dose-dependent manner. Cell proliferation and migration outcomes obtained with PRGF (from both groups) were significantly higher compared to non-stimulated groups (pPRGF, however, with the exception of VEGF, no statistical significances were observed between the different age groups. Results from this study concluded that PRGF is safe and effective in stimulating skin regeneration by enhancing proliferation, migration and expression of pivotal bioactive molecules involved in wound healing and haemostasis.

  19. Overexpression of Myo1e in mouse podocytes enhances cellular endocytosis, migration, and adhesion.

    Science.gov (United States)

    Jin, Xia; Wang, Wenjing; Mao, Jianhua; Shen, Huijun; Fu, Haidong; Wang, Xia; Gu, Weizhong; Liu, Aimin; Yu, Huimin; Shu, Qiang; Du, Lizhong

    2014-02-01

    Podocytes are a terminally differentiated and highly specialized cell type in the glomerulus that forms a crucial component of the glomerular filtration barrier. Recently, Myo1e was identified in the podocytes of glomeruli. Myo1e podocyte-specific knockout mice exhibit proteinuria, podocyte foot process effacement, glomerular basement membrane disorganization, signs of chronic renal injury, and kidney inflammation. After overexpression of Myo1e in a conditionally immortalized mouse podocyte cell line (MPC5), podocyte migration was evaluated via transwell assay, endocytosis was evaluated using FITC-transferrin, and adhesion was evaluated using a detachment assay after puromycin aminonucleoside treatment. Myo1e overexpression significantly increased the adherence of podocytes. ANOVA analysis indicated significant differences for cell adhesion between the overexpression and control groups (overexpression vs. control, t = 11.3199, P = 0.005; overexpression vs. negative control, t = 12.0570, P = 0.0006). Overexpression of Myo1e inhibited puromycin aminonucleoside-induced podocyte detachment, and the number of cells remaining on the bottom of the culture plate increased. Cell migration was enhanced in Myo1e-overexpressing podocytes in the transwell migration assay. Internalization of FITC-transferrin also increased in Myo1e-overexpressing podocytes relative to control cells. Overexpression of Myo1e can enhance podocyte migration ability, endocytosis, and attachment to the glomerular basement membrane. Restoration of Myo1e expression in podocytes may therefore strengthen their functional integrity against environmental and mechanical injury. © 2013 Wiley Periodicals, Inc.

  20. HGF potentiates extracellular matrix-driven migration of human myoblasts: involvement of matrix metalloproteinases and MAPK/ERK pathway.

    Science.gov (United States)

    González, Mariela Natacha; de Mello, Wallace; Butler-Browne, Gillian S; Silva-Barbosa, Suse Dayse; Mouly, Vincent; Savino, Wilson; Riederer, Ingo

    2017-10-10

    The hepatocyte growth factor (HGF) is required for the activation of muscle progenitor cells called satellite cells (SC), plays a role in the migration of proliferating SC (myoblasts), and is present as a soluble factor during muscle regeneration, along with extracellular matrix (ECM) molecules. In this study, we aimed at determining whether HGF is able to interact with ECM proteins, particularly laminin 111 and fibronectin, and to modulate human myoblast migration. We evaluated the expression of the HGF-receptor c-Met, laminin, and fibronectin receptors by immunoblotting, flow cytometry, or immunofluorescence and used Transwell assays to analyze myoblast migration on laminin 111 and fibronectin in the absence or presence of HGF. Zymography was used to check whether HGF could modulate the production of matrix metalloproteinases by human myoblasts, and the activation of MAPK/ERK pathways was evaluated by immunoblotting. We demonstrated that human myoblasts express c-Met, together with laminin and fibronectin receptors. We observed that human laminin 111 and fibronectin have a chemotactic effect on myoblast migration, and this was synergistically increased when low doses of HGF were added. We detected an increase in MMP-2 activity in myoblasts treated with HGF. Conversely, MMP-2 inhibition decreased the HGF-associated stimulation of cell migration triggered by laminin or fibronectin. HGF treatment also induced in human myoblasts activation of MAPK/ERK pathways, whose specific inhibition decreased the HGF-associated stimulus of cell migration triggered by laminin 111 or fibronectin. We demonstrate that HGF induces ERK phosphorylation and MMP production, thus stimulating human myoblast migration on ECM molecules. Conceptually, these data state that the mechanisms involved in the migration of human myoblasts comprise both soluble and insoluble moieties. This should be taken into account to optimize the design of therapeutic cell transplantation strategies by improving