High-throughput single-molecule quantification of individual base stacking energies in nucleic acids.

Base stacking interactions between adjacent bases in DNA and RNA are important for many biological processes and in biotechnology applications. Previous work has estimated stacking energies between pairs of bases, but contributions of individual bases has remained unknown. Here, we use a Centrifuge Force Microscope for high-throughput single molecule experiments to measure stacking energies between adjacent bases. We found stacking energies strongest between purines (G|A at -2.3 ± 0.2 kcal/mol) and weakest between pyrimidines (C|T at -0.5 ± 0.1 kcal/mol). Hybrid stacking with phosphorylated, methylated, and RNA nucleotides had no measurable effect, but a fluorophore modification reduced stacking energy. We experimentally show that base stacking can influence stability of a DNA nanostructure, modulate kinetics of enzymatic ligation, and assess accuracy of force fields in molecular dynamics simulations. Our results provide insights into fundamental DNA interactions that are critical in biology and can inform design in biotechnology applications.

Health behaviours and COVID-19 prevention among immigrants in the United States.

Recent studies indicate that the COVID-19 pandemic has had negative implications for the welfare of immigrant communities. However, few studies have examined the behavioural responses used by immigrants to respond to the spread of the virus. This study uses data from the U.S.-based COVID-19 in American Communities study to examine whether there are disparities in the use of COVID-19 prevention behaviours between first-generation immigrants (i.e., foreign-born persons), second-generation immigrants (i.e., U.S.-born persons with at least one immigrant parent), and third-generation individuals (i.e., U.S.-born persons with only U.S.-born parents). The results indicate that recent first-generation immigrants and second-generation immigrants use the behaviours recommended to prevent the spread of COVID-19 less intensively compared to third-generation individuals. Furthermore, increased exposure to U.S. society is found to have a non-linear relationship with the intense use of these behaviours. Results from the analysis of each preventive behaviour show that there are larger gaps between immigrants and U.S. natives in the use of frequent hand washing and comparatively smaller gaps in the practice of avoiding large crowds. However, the most consistent pattern of low use of COVID-19 prevention behaviours was found among recently arrived first-generation immigrants.

Racial/ethnic and nativity disparities in U.S. Covid-19 vaccination hesitancy during vaccine rollout and factors that explain them.

While research has begun to investigate disparities in Covid-19 vaccine hesitancy between White, Black and Hispanic adults, no nationally representative studies to date have accounted for Hispanic immigrants as a unique group or fully investigated the reasons behind racial/ethnic and nativity disparities. We make these contributions by substantively drawing from what is known about the ways that immigrant fear and structural racism create conditions that produce countervailing forces that are likely to contribute to racial/ethnic and nativity disparities in vaccine hesitancy. We use OLS regression and decomposition techniques to analyze data from 1936 18-65 year-old United States (U.S.) adults who participated in the COVID-19 and its Implications for American Communities (CIAC) study during February and March 2021, a period of time that coincides with early stages of the U.S. vaccine roll-out effort that pre-dated universal adult eligibility for Covid-19 vaccination. Results indicate that U.S.-born Black adults are more vaccine hesitant than U.S.-born White adults. This disparity is largely due to differences in anti-vaccine beliefs. U.S.-born Hispanic adults are less vaccine hesitant than U.S.-born White adults in adjusted OLS regression models and personal experiences with Covid-19 drive this difference. There were not significant differences between foreign-born Hispanic and U.S.-born White adults in vaccine hesitancy. These findings suggest that foreign-born Hispanic adults did not drive early disparities in vaccine hesitancy and that alleviating concerns about anti-vaccine beliefs and utilizing personal stories have important roles in preventing future racial/ethnic disparities in Covid-19 vaccine hesitancy as new Covid-19 vaccines and booster shots are rolled out. Study findings may also have implications for reducing racial/ethnic disparities in the uptake of other new vaccines.

Racial Family Configurations and Inequalities in Private School Enrollment Among Adopted Children.

This study uses data from the American Community Survey to examine the relationship between race, family configurations, and inequalities in private school enrollment among adoptees. We find that private school enrollment is higher in transracial than in same-race families. This disparity is driven by the outcomes of adoptees in transracial families with zero rather than one same-race parent. Among adoptees themselves, there are diverging patterns of racial stratification in same-race and transracial families. White adoptees in same-race families are more likely to be enrolled in private school than Black, Asian, or Hispanic adoptees in such families. However, among adoptees in transracial families, the highest odds of private school enrollment are found among Asians. Finally, we argue that our findings have important implications for understanding how kinship cues, compensation, and social disadvantage shape parental investment in adopted children.

Parental STEM credentials and children's schooling progress in immigrant and U.S. born families.

Although many previous studies have examined the outcomes of STEM graduates, there is very limited research examining the educational attainment of their children. Given the increasing contribution of immigration to the supply of STEM graduates, we use data from the ACS to examine disparities in children's schooling progress in the families of immigrant and U.S born STEM graduates. Our analysis shows several findings. First, the children of STEM graduates are less likely to fall behind in school than the children of graduates in Business, Arts/Humanities, and other fields of study. This relative STEM advantage is, however, stronger in immigrant than U.S born families. Second, the children of immigrant STEM graduates have more favorable outcomes than the children of U.S. born STEM graduates; however, the favorable outcomes of the former are more consistent for children whose parents have U.S. rather than foreign STEM degrees. Finally, our results show that it is only among the children of STEM graduates that we find lower odds of schooling progress among 1.75- compared to second-generation children. These odds are statistically significant, implying that there is some convergence in the outcomes of first- and second-generation children of immigrant STEM graduates.

Adoption status and disparities in the familial configurations of children.

Few studies have examined the familial configurations of adopted children and how these configurations differ from those of non-adoptees. As a result, this study examines the relationship between adoption status and inequalities in the family structure of children. Our results indicate that adopted children are more likely to live in nuclear families compared to non- adopted children. Part of this is driven by the comparatively limited presence of adoptees in single-mother, single-father, and other types of non-nuclear families. Foreign-born adoptees are more likely to live in nuclear families compared to U.S.-born adoptees, but adoptees from racial and ethnic minority groups are less likely to live in such families compared to their white counterparts. These race-ethnic inequalities in family structure are however moderated by foreign-born status. Accordingly, our results indicate that foreign-born black and Hispanic children have the highest odds of residing in nuclear families among the U.S. population of adopted children.

Parental influence and private school enrollment among children in blended families.

In this study, the analysis examines how variations in parental influence shape private school enrollment among children in blended families. The results show that investment in private schooling for children is higher in families with notable parental income differences than in families with parents with similar incomes. Net of these factors, however, parents in nuclear families are more likely to invest in the provision of private schooling compared to parents in blended families. In blended families, the analysis underscores the significance of two dimensions of biological relatedness for developing nuanced understandings of inequalities among children. On average, parents in these families make greater investments in the provision of private schooling for their shared biological children than for their stepchildren, broadly defined. Disaggregating stepchildren based on their own biological ties with parents, however, reveals substantially higher investments in private schooling for stepchildren biologically related to household heads than for either shared biological children or other stepchildren. The advantage of stepchildren with biological ties to household heads is more pronounced in families where household heads earn more than their spouses. However, it remains statistically significant even when the opposite is true.

Adoption, Foreign-Born Status, and Children's Progress in School.

Using recent data from the American Community Survey, the author investigated how the dynamics of immigration influence our understanding of the adoption-schooling relationship. The results suggest that implications of immigrant and adoption statuses could be understood within specific familial contexts. Thus, no statistical differences were found in the outcomes of foreign-born adoptees in U.S. native families and their peers with immigrant parents. Instead, the most favorable patterns of schooling progress were found among U.S.-born adoptees living in immigrant families. Among immigrants, the analysis indicated similar patterns of achievement among Hispanic and White adoptees that are inconsistent with the predictions of segmented assimilation theory. However, there was a Hispanic disadvantage relative to Whites among immigrant children living with biological and stepparents. The article concludes with a discussion of the implications of these findings for kinship selection and assimilation processes and the contention that alternative theoretical frameworks should be used to understand the implications of adoption status.

Occupational stratification, job-mismatches, and child poverty: understanding the disadvantage of Black immigrants in the US.

This study examines the implications of occupational stratification and job mismatches for the welfare of children, using data from the 2005-2009 American Community Survey. The results show that Black children of immigrants have household heads that are more likely to have occupations with low SEI scores than children in US-born households. More importantly, they demonstrate that intersections between parental job-mismatches and employment in the bottom rather than upper levels of the occupational distribution have important implications for understanding poverty differences among children. Job mismatches within occupations with low SEI scores are associated with greater poverty risks among Black than White, Asian, or Hispanic children of immigrants. However, racial poverty disparities are considerably lower among children with household heads in the highest occupational strata.

Child Poverty During the Years of the Great Recession: An Analysis of Racial Differences Among Immigrants and US Natives.

Although the consequences of the Great Recession are extensively discussed in previous research, three critical issue need to be addressed in order to develop a full portrait of the economic experiences of children during this period. First, given the changing immigrant composition of the US child population, new studies are needed for examining the implications of immigrant status for exposure to child poverty during the recession. Second, it is important to understand how traditional patterns of racial inequality among were transformed during the years of the recession. Finally, it is not clear whether recession-related changes in socioeconomic inequalities continued to have implications for child well-being in the post-recession period. Results from this analysis indicate that the adverse effects of the recession were most intense in states with significant changes in their populations of Black and Latino immigrant children. The results further show that declines in parental work opportunities were more consequential for poverty among Whites and Asians. The analysis also finds differential implications of family contexts for child poverty among Black immigrant and natives during the recession. Finally, the results indicate that increases in racial child poverty disparities during the recession did not disappear in the years following the downturn.

Migration dynamics, entrepreneurship, and African development: Lessons from Malawi.

Using data from Malawi, this study situates the discourse on migration, entrepreneurship, and development within the context of Africa's social realities. It examines self-employment differences among three groups of migrants and corresponding group differences in agricultural and non-agricultural self-employment. International migrants are found to be more engaged in self-employment than internal-migrants. However, our results suggest that previous findings on the development-related contributions of returning migrants from the West need to be appropriately contextualized. When returnees from the West invest in self-employment, they typically shy away from Africa's largest economic sector - agriculture. In contrast, levels of self-employment, especially in agricultural self-employment, are highest among returning migrants and immigrants from other African countries, especially from those nearby. We also underscore the gendered dimensions of migrants' contribution to African development by demonstrating that female migrants are more likely to be self-employed in agriculture than male migrants. Furthermore, as human-capital increases, migrants are more likely to concentrate their self-employment activities in non-agricultural activities and not in the agricultural sector. The study concludes by using these findings to discuss key implications for policy and future research.

Race and school enrollment among the children of African immigrants in the United States.

This study examines whether previous findings of an immigrant schooling advantage among Blacks in the United States reflect a declining significance of race in the enrollment patterns of immigrants' children. Using data from the 2000 US census, the study finds that, despite their advantage within the Black population, the children of Black Africans are collectively disadvantaged relative to the children of White Africans. Disparate enrollment trajectories are found among children in Black and White African families. Specifically, between the first and second generations, enrollment outcomes improved among the children of White Africans but declined among Black Africans' children. The results also suggest that among immigrants from African multi-racial societies, pre-migration racial schooling disparities do not necessarily disappear after immigration to the United States. Additionally, the children of Black Africans from these contexts have worse outcomes than the children of other Black African immigrants and their relative disadvantage persists even after other factors are controlled.

Migration processes, familial characteristics, and schooling dropout among black youths.

This study uses data from the 2000 U.S. census to examine whether the schooling advantage of black immigrants' children found in previous studies is robust. According to the results, the advantage associated with having migrant parents is not restricted to the children of immigrants. Black migrant parents, regardless of foreign-born status, have children with favorable schooling outcomes. Such parental-level influences, however, seem stronger among some immigrant groups than among native internal migrants. The study also suggests that the collective advantage of the children of immigrants is driven by positive migrant selectivity. Accordingly, comparisons between the children of native migrants and children in various immigrant groups reveal that the immigrant advantage is not robust. In fact, the results suggest that when immigrant ethnicity is considered, some children of immigrants may be disadvantaged relative to the children of native migrants. Among recent migrants, the children of native internal migrants also have more favorable outcomes than the children of immigrants, although these differences disappear after background factors are controlled. Further, internal-migrant and immigrant households are less likely to have characteristics that adversely affect schooling than nonmigrant households. Unsurprisingly, the children of nonmigrants have the worst outcomes among black youths.

The U.S. Diversity Visa Programme and the Transfer of Skills from Africa.

The Diversity Visa (DV) programme is designed to improve the multicultural composition of the U.S. "melting pot" beyond the traditional source countries in Europe. In pursuit of this objective, the basic eligibility requirement for participation in the programme is a high school diploma. Despite its salutary objective and design, the programme's implications for the African brain drain may not all be benign. The "tired, poor, huddled masses" from Africa are defined in more restrictive terms, and the obstacles they face are more economically and administratively onerous than those encountered by their early European counterparts. The costs of transforming a lottery win to an actual diversity visa and Green Card are so high that only Africans in well-paying jobs, who are likely to be professionals rather than mere high school graduates, are likely to be able to afford the full costs of programme participation. In this sense, the programme has an in-built, skills-selective mechanism. The main objective of this study is to examine the extent to which the DV has facilitated the movement of professional, technical and kindred workers (PTKs) from Africa to the United States, and some of the economic and policy implications of the process.

The human capital characteristics and household living standards of returning international migrants in Eastern and Southern Africa.

Africa's experience with return migration is not new. However, few empirical studies have examined the social and economic characteristics of returning migrants within the continent. In this study, the human capital endowments and household living standards of returning migrants in Uganda and South Africa are examined using recently available data. The study compares returnees in both countries with immigrants as well as the native-born population with no international migration experience. It also investigates how factors such as previous country of residence, year of arrival, and other demographic factors predict levels of education and living standards among returning migrants. In Uganda, the results show that recently arrived returning migrants had better educational endowments than both immigrants and non-migrants. Migrants who returned to Uganda following the fall of Idi Amin's regime had the lowest educational levels and lowest living standards compared to other returnees. Furthermore, the results indicate that previous residence in countries in the West was associated with four additional years of schooling while returning migrants arriving from other African countries had the lowest levels of schooling among returning migrants. In South Africa, the study finds that returnees arriving almost immediately following the end of Apartheid had the highest levels of education compared to either immigrants or non-migrants. Returnees on average also had the highest household living standards in South Africa. Among South African immigrants, the results indicate that those arriving towards the end of the century had lower educational endowments compared to immigrants who arrived in the country two to four years after the end of Apartheid.

Migration, Household Configurations, and the Well-Being of Adolescent Orphans in Rwanda.

This study uses data from the 2002 Rwandan census to situate the discourse on migration and orphan well-being within the context of the household. According to its findings, migrant orphans are less likely than non-migrant orphans to live in households with less favorable structural characteristics such as single-parent households. Significant differences are also found in the implied gains to living standards and schooling associated with migration among paternal, maternal, and double-orphans. However, the higher living standards and schooling attainment of orphan migrants relative to their non-migrant counterparts disappear within child-headed household contexts. More generally, the results indicate that the higher living standards of migrant orphans are in part driven by the fact that they mostly live in households with migrant household-heads or migrant spouses. Yet the analysis also suggests that orphans living within these contexts experience higher levels of intra-household discrimination in investments in their schooling, relative to their orphan counterparts who live in non-migrant households.

African female immigration to the United States and its policy implications.

This study examines the dynamics of female African immigration and settlement in the United States and discusses the research and policy implications for these processes. It highlights a significant surge in female immigration from African than non-African countries in recent years. This surge is driven by female immigration from Africa's countries most populous countries, from countries affected by civil conflicts, and from English-speaking countries in the region. African women are also more likely to arrive as unmarried single than other female immigrants. In addition, they had the highest prevalence of Bachelors, Masters, or Doctorate degrees among women in the US. African females were also about twice more likely to be enrolled in US Educational institutions compared to other women. Those in the labor force were more likely to work as nursing professionals than in technical occupational groups such as engineering and computing. The study concludes by discussing the research and policy implications of these findings for countries in the developing world.

Familial influences on poverty among young children in black immigrant, U.S.-born black, and nonblack immigrant families.

This study examines how familial contexts affect poverty disparities between the children of immigrant and U.S.-born blacks, and among black and nonblack children of immigrants. Despite lower gross child poverty rates in immigrant than in U.S.-born black families, accounting for differences in family structure reveals that child poverty risks among blacks are highest in single-parent black immigrant families. In addition, within two-parent immigrant families, child poverty declines associated with increasing assimilation are greater than the respective declines in single-parent families. The heads of black immigrant households have more schooling than those of native-black households. However, increased schooling has a weaker negative association with child poverty among the former than among the latter. In terms of racial disparities among the children of immigrants, poverty rates are higher among black than nonblack children. This black disadvantage is, however, driven by the outcomes of first-generation children of African and Hispanic-black immigrants. The results also show that although children in refugee families face elevated poverty risks, these risks are higher among black than among nonblack children of refugees. In addition, the poverty-reducing impact associated with having an English-proficient household head is about three times lower among black children of immigrants than among non-Hispanic white children of immigrants.

The living arrangements of children of immigrants.

Children of immigrants are a rapidly growing part of the U.S. child population. Their health, development, educational attainment, and social and economic integration into the nation's life will play a defining role in the nation's future. Nancy Landale, Kevin Thomas, and Jennifer Van Hook explore the challenges facing immigrant families as they adapt to the United States, as well as their many strengths, most notably high levels of marriage and family commitment. The authors examine differences by country of origin in the human capital, legal status, and social resources of immigrant families and describe their varied living arrangements, focusing on children of Mexican, Southeast Asian, and black Caribbean origin. Problems such as poverty and discrimination may be offset for children to some extent by living, as many do, in a two-parent family. But the strong parental bonds that initially protect them erode as immigrant families spend more time in the United States and are swept up in the same social forces that are increasing single parenthood among American families. The nation, say the authors, should pay special heed to how this aspect of immigrants' Americanization heightens the vulnerability of their children. One risk factor for immigrant families is the migration itself, which sometimes separates parents from their children. Another is the mixed legal status of family members. Parents' unauthorized status can mire children in poverty and unstable living arrangements. Sometimes unauthorized parents are too fearful of deportation even to claim the public benefits for which their children qualify. A risk factor unique to refugees, such as Southeast Asian immigrants, is the death of family members from war or hardship in refugee camps. The authors conclude by discussing how U.S. immigration policies shape family circumstances and suggest ways to alter policies to strengthen immigrant families. Reducing poverty, they say, is essential. The United States has no explicit immigrant integration policy or programs, so policy makers must direct more attention and resources toward immigrant settlement, especially ensuring that children have access to the social safety net.