Migration Propensities Research Articles

A Longitudinal Study of Migration Propensities for Mixed Ethnic Unions in England and Wales

Most studies investigating residential segregation of ethnic minorities ignore the fact that the majority of adults live in couples. In recent years there has been a growth in the number of mixed ethnic unions that involve a minority member and a white member. To our knowledge, hardly any research has been undertaken to explicitly examine whether the ethnic mix within households has an impact on the residential choices of households in terms of the ethnic mix of destination neighbourhoods. Our study addresses this research gap and examines the tendencies of migration among mixed ethnic unions in comparison with their co-ethnic peers. We used data from the Longitudinal Study for England and Wales. Our statistical analysis supports the spatial assimilation theory: ethnic minorities move towards less deprived areas and to a lesser extent also towards less ethnically concentrated areas. However, the types of destination neighbourhood of minority people living in mixed ethnic unions varied greatly with the ethnicity of the ethnic minority partner.

A comparison of internal migration by ethnic group in Great Britain using a district classification

This paper considers the ethnic dimension of changing usual residence using 1-year data from the 2001 Census, the only available comprehensive source of origin-destination flow data on Whites and non-white minority groups. The analysis identifies the variation in migration propensities at national level by ethnic group and by age and investigates spatial patterns of ethnic migration at local authority district scale using an area classification based on migration variables extracted from the 2001 Census.

North‐South Migration in Ghana: What Role for the Environment?

AbstractThe purpose of this paper is to determine the importance of the environment as a driver of North‐South migration in Ghana. Almost one in every five people born in northern Ghana is living in southern Ghana. Interviews with 203 migrant farmers suggest that migration from the North to the South is, to a large extent, environmentally induced. Many Northerners decided to migrate because of poor agro‐ecological conditions at home combined with easy access to fertile lands in the more humid destination area. The interviews with migrant farmers yielded several insights that are relevant for the environmental refugee debate. Firstly, environmental pull appears to be at least as important as environmental push. Secondly, scarcity of fertile land was mentioned much more often as a reason to migrate than climate change or erratic rainfall. Thirdly, none of the respondents ascribed the migration decision to sudden‐onset environmental stress. If the environment is indeed an important driver of migration, one would expect migration rates to be higher in places with and times of more severe scarcity. A cross‐sectional analysis of migration propensities and natural resources scarcity confirms that out‐migration rates are significantly higher in poorly endowed districts. A longitudinal analysis of migration and rainfall shows that the period of worst environmental stress ‐‐ during the Sahelian droughts of the late 1970s and early 1980s ‐‐ was a time of reduced out‐migration from northern Ghana. In this period of northern Ghana’s migration history, economic and political factors weighed heavier than environmental factors. The picture that emerges for northern Ghana is not one of distress migration in the face of environmental disaster but rather of migration as a way of dealing with structural environmental scarcity.

Abstract 2370: Single cell analysis using a microscale migration slide

Abstract Cell migration occurs in a variety of biological processes including wound healing, embryonic development, and immune responses. Existing chemotaxis assays used to assess cell migration employ the Boyden chamber which lack real-time imaging capability and does not maintain well defined biomolecular gradients. To overcome these limitations, a cell migration assay was developed which enabled real-time monitoring of single cells on a slide-like platform that maintained a stable linear gradient. Fluorescence measurements with albumin (MW=66kDa) conjugated with FITC demonstrated that the concentration profile was linear over the 1 mm observation area. This linear concentration gradient was established after 1 hour incubation and was stable for over 24 hours. The microscale migration slide was used to assess the effects of serum concentrations (0, 2, 5, 10, and 15%) on the migration propensity of four different cell lines that were grown on collagen. The cell lines included cancer cell lines with known invasive properties (fibrosarcoma cancer cells HT1080 and breast cancer cells MDA-MB-231), along with HUVECs which are angiogenic cells involved in tumor metastasis and a control cell line, NIH 3T3 fibroblast cells. Cells were incubated in the experimental conditions overnight (12 hours) with images captured every 15 minutes. Migration of single cells was monitored and imaged in real-time and the percentage of cells that exhibited positive migration towards the chemotactic source was calculated. Interestingly, we observed that the highest percentage of migratory HUVEC cells was obtained using 2% serum whereas the other three cell lines exhibited increased migration with increasing serum concentration. Under similar culture conditions of either 10 or 15% serum, MDA-MB-231 possessed the highest migration index, followed by NIH 3T3 fibroblasts and HT1080 cells whereas HUVEC cells did not migrate at all under these high serum conditions. Extensive testing over a range of conditions with different users indicated remarkable consistency in the data generated and suggests that the migration slide is a useful tool to monitor the effects of chemoattractants on adherent cell lines. Overall the results provide a reference point from which to build upon future studies aimed at comparing the effects of signaling molecules and growth factors on the migration propensities of cancer cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2370. doi:10.1158/1538-7445.AM2011-2370

Synthesis of a series of phenylacetic acid 1-β-O-acyl glucosides and comparison of their acyl migration and hydrolysis kinetics with the corresponding acyl glucuronides

We report the synthesis of the 1-β-O-acyl glucoside conjugates of phenylacetic acid (PAA), R- and S-α-methyl-PAA and α,α'-dimethyl-PAA, and measurement of their transacylation and hydrolysis reactivity by NMR methods. These are analogues of acyl glucuronides, the transacylation kinetics of which could be important in adverse drug effects. One aim of this work was to investigate whether, as previously postulated, the free carboxylate group of the acyl glucuronides plays a part in the mechanism of the internal acyl migration. In addition, such acyl glucosides are known to be endogenous biochemicals in their own right and investigation of their acyl migration propensities is novel. Our previously described selective acylation procedure has proved highly successful for 1-β-O-acyl glucuronide synthesis and when subsequently applied to 6-O-trityl glucose, it gave good yields and excellent anomeric selectivity. Mild acidolysis of the O-trityl intermediates gave the desired acyl glucosides in excellent yield with essentially complete β-selectivity. Measurement of the acyl glucoside transacylation kinetics by (1)H NMR spectroscopy, based simply on the disappearance of the 1-β-isomer in aqueous buffer at pH 7.4, showed marked differences depending on the degree of methyl substitution. Further kinetic modelling of the isomerisation and hydrolysis reactions of the acyl glucosides showed considerable differences in kinetics for the various isomeric reactions. Reactions involving the -CH(2)OH group, presumably via a 6-membered ring ortho-ester intermediate, are facile and the α-glucoside anomers are significantly more reactive than their β-counterparts. By comparison with degradation rates for the corresponding acyl glucuronides, it can be inferred that substitution of the carboxylate by -CH(2)OH in the acyl glucosides has a significant effect on acyl migration for those compounds, especially for rapidly transacylating molecules, and that thus the charged glucuronide carboxylate is a factor in the kinetics.

Direct Evidence on Risk Attitudes and Migration

Geographic mobility is important for the functioning of labor markets because it brings labor resources to where they can be most efficiently used. It has long been hypothesized that individuals' migration propensities depend on their attitudes towards risk, but the empirical evidence, to the extent that it exists, has been indirect. In this paper, we use newly available data from the German Socio-Economic Panel to measure directly the relationship between migration propensities and attitudes towards risk. We find that individuals who are more willing to take risks are more likely to migrate between labor markets in Germany. This result is robust to stratifying by age, sex, education, national origin, and a variety of other demographic characteristics, as well as to the level of aggregation used to define geographic mobility. The effect is substantial relative to the unconditional migration propensity and compared to the conventional determinants of migration. We also find that being more willing to take risks is more important for the extensive than for the intensive margin of migration.

Determinants of the Estimation of Return Migration Propensities among Young People in the Face of Risk: Accra, Ghana

Determinants of the Estimation of Return Migration Propensities among Young People in the Face of Risk: Accra, Ghana

The microeconomic determinants of emigration and return migration of the best and brightest: Evidence from the Pacific

A unique survey which tracks worldwide the best and brightest academic performers from three Pacific countries is used to assess the extent of emigration and return migration among the very highly skilled, and to analyze, at the microeconomic level, the determinants of these migration choices. Although we estimate that the income gains from migration are very large, not everyone migrates and many return. Within this group of highly skilled individuals the emigration decision is found to be most strongly associated with preference variables such as risk aversion and patience, and choice of subjects in secondary school, and not strongly linked to either liquidity constraints or to the gain in income to be had from migrating. Likewise, the decision to return is strongly linked to family and lifestyle reasons, rather than to the income opportunities in different countries. Overall the data suggest a relatively limited role for income maximization in distinguishing migration propensities among the very highly skilled, and a need to pay more attention to other components of the utility maximization decision.

Introduction

Introduction

Internal migration in Britain, 2000–01, examined through an area classification framework

AbstractThis paper explores the age variations in origin–destination migration data from the 2001 UK Census. It does so using a national district classification as a framework for summarising what is a series of matrices, each containing very large numbers of cells. The results demonstrate how migration propensities and patterns vary between different types of district, providing new insights into the processes through which the population is redistributed throughout Great Britain. Copyright © 2009 John Wiley & Sons, Ltd.

The Microeconomic Determinants of Emigration and Return Migration of the Best and Brightest: Evidence from the Pacific

A unique survey which tracks worldwide the best and brightest academic performers from three Pacific countries is used to assess the extent of emigration and return migration among the very highly skilled, and to analyze, at the microeconomic level, the determinants of these migration choices. Although we estimate that the income gains from migration are very large, not everyone migrates and many return. Within this group of highly skilled individuals the emigration decision is found to be most strongly associated with preference variables such as risk aversion, patience, and choice of subjects in secondary school, and not strongly linked to either liquidity constraints or to the gain in income to be had from migrating. Likewise, the decision to return is strongly linked to family and lifestyle reasons, rather than to the income opportunities in different countries. Overall the data show a relatively limited role for income maximization in distinguishing migration propensities among the very highly skilled, and a need to pay more attention to other components of the utility maximization decision.

The internal migration propensities and net migration patterns of ethnic groups in Britain

Internal migration propensities of ethnic groups are examined using three types of census data. Special Migration Statistics show variation in aggregate propensities whereas commissioned age-specific flow data indicate age variations by ethnic group. Micro data from Samples of Anonymised Records confirm low Asian propensities and suggest convergence between 1991 and 2001. Inter-district net migration reveals familiar counterurbanisation trends for whites but more complex patterns for non-whites. Evidence suggests white net migration at this scale is greater in areas with higher non-white population shares which themselves experience higher non-white immigration rates.

Health, human capital, and African-American migration before 1910

Using both IPUMS and the Colored Troops Sample of the Civil War Union Army Data, I estimate the effects of literacy and health on the migration propensities of African-Americans from 1870 to 1910. I find that literacy and health shocks were strong predictors of migration and the stock of health was not. There were differential selection propensities based on slave status—former slaves were less likely to migrate given a specific health shock than free blacks. Counterfactuals suggest that as much as 35% of the difference in the mobility patterns of former slaves and free blacks is explained by differences in their human capital, and more than 20% of that difference is due to health alone. Overall, the selection effect of literacy on migration is reduced by one-tenth to one-third once health is controlled for. The low levels of human capital accumulation and rates of mobility for African-Americans after the Civil War are partly explained by the poor health status of slaves and their immediate descendants.

Inferring Directional Migration Propensities from the Migration Propensities of Infants in the United States

Beginning with the 2010 decennial census, the U.S. Census Bureau plans to drop its long-form questionnaire and to replace it with the American Community Survey (ACS). The resulting absence of the larger sample provided by the census count will complicate the measurement and analysis of internal migration flows. In addition, the strategy of averaging accumulated samples over time will mix changing migration patterns. The migration question will refer to a one-year time interval instead of the five-year interval used in the censuses between 1960 and 2000, complicating historical comparisons and the production of multiregional projections based on five-year age groups. Consequently, students of territorial mobility increasingly will find it necessary to complement or augment possibly inadequate data collected on migration with estimates obtained by means of “indirect estimation.” A method is presented that allows one to infer age-specific directional migration propensities at the regional level from birthplace-specific infant population data, which approximates infant migration propensities, and from these infers the migration propensities of all other ages. The method is applied to at the nine-division spatial scale.

The peritoneal micromilieu commits B cells to home to body cavities and the small intestine

AbstractThe distinct combination of homing receptors such as selectins, chemokine receptors, and integrins directs the migration of lymphocytes throughout the body. Upon activation lymphocytes irreversibly switch their set of homing receptors, now guiding them to entirely different destinations. Here we report that exposure of naive B cells to the microenvironment of the peritoneal cavity modulates their migration propensities in the absence of antigenic stimulation. B1 and B2 cells isolated from the peritoneal cavity reenter this compartment more efficiently compared with splenic follicular B cells. Moreover, when kept in the peritoneal cavity splenic follicular B cells gain such increased capability to reenter this compartment. These altered migratory capacities are reflected by an up-regulation of the chemokine receptors CXCR4 and CXCR5 and β7 integrin by the peritoneum-experienced splenic B cells, among which CXCR5 is instrumental in directing B cells into the peritoneal cavity. Moreover, intraperitoneal transfer of plasma blasts favors their migration into the small intestine presumably before class switch recombination occurs, demonstrating that a reconfigured transient migration pattern is not restricted to naive cells. In conclusion, these data demonstrate a hitherto unrecognized role for tissue-specific cues, altering the migratory capacity of B1, naive B2, as well as antigen-experienced B2 cells.

Inferring migration flows from the migration propensities of infants: Mexico and Indonesia

The need for methods of indirectly estimating migration flows is particularly important in developing countries, where migration data are often incomplete and inaccurate. This paper focuses on the use of an indirect internal migration estimation method applied to Mexican and Indonesian census data. It shows that the mobility propensities of infants can be used to infer the corresponding propensities of all other age groups. However, the promise of this method is reduced in instances of inadequate data, and great care must be taken to identify outlying values in the data and to correct obviously erroneous patterns. Future work increasingly will be directed to this issue.

Direct Evidence on Risk Attitudes and Migration

Geographic mobility is important for the functioning of labor markets because it brings labor resources to where they can be most efficiently used. It has long been hypothesized that individuals' migration propensities depend on their attitudes towards risk, but the empirical evidence, to the extent that it exists, has been indirect. In this paper, we use newly available data from the German Socio-Economic Panel to measure directly the relationship between migration propensities and attitudes towards risk. We find that individuals who are more willing to take risks are more likely to migrate between labor markets in Germany. This result is robust to stratifying by age, sex, education, national origin, and a variety of other demographic characteristics, as well as to the level of aggregation used to define geographic mobility. The effect is substantial relative to the unconditional migration propensity and compared to the conventional determinants of migration. We also find that being more willing to take risks is more important for the extensive than for the intensive margin of migration.

The Relocation Decisions of Working Couples

Most prime-age married couples in the U.S. today have two labor force participants. Migration decisions are more complicated for two-earner couples than for one-earner couples because any gain from moving that accrues to one spouse must be great enough to offset any loss to the other spouse. This paper estimates the extent to which internal migration is depressed by rising earnings equality among spouses. The results indicate that couples' migration propensities are substantially lower the more equal spouses' labor incomes.

The Relocation Decisions of Working Couples

Most prime-age married couples in the U.S. today have two labor force participants. Migration decisions are more complicated for two-earner couples than for one-earner couples because any gain from moving that accrues to one spouse must be great enough to offset any loss to the other spouse. This paper estimates the extent to which internal migration is depressed by rising earnings equality among spouses. The results indicate that couples' migration propensities are substantially lower the more equal spouses' labor incomes.

Who moves and who stays? Rural out-migration in Nigeria

Data from the nationally representative 1993 Migration and Urbanization Survey of Nigeria are used to simultaneously examine the patterns of rural-rural and rural-urban migration in Nigeria. A multinomial logistic regression model predicts the independent and collective association between individual, household, and regional variables and migration from rural areas to rural and urban destinations. Associations between education, religion and ethnicity and migration propensities exist at the national level. The Kanuri-Shua Arabs are generally non-migrants, the Hausa-Fulani and Yoruba are predominantly rural-rural migrants and the Igbo-Ibibio and Urhobo-Isoko-Edo are predominantly ruralurban migrants. Christians are significantly more mobile than Muslims. While the highly educated are most likely to choose an urban destination, a significant proportion migrate to other rural areas. Concern over population concentration is not supported, as rural migrants move to all regions and to urban and rural areas.