抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

How we raise young children is one of today's most highly personalized and sharply politicized issues, in part because each of us can claim some level of "expertise." The debate has intensified as discoveries about our development-in the womb and in the first months and years-have reached the popular media. How can we use our burgeoning knowledge to assure the well-being of all young children, for their own sake as well as for the sake of our nation? Drawing from new findings, this book presents important conclusions about nature-versus-nurture, the impact of being born into a working family, the effect of politics on programs for children, the costs and benefits of intervention, and other issues. The committee issues a series of challenges to decision makers regarding the quality of child care, issues of racial and ethnic diversity, the integration of children's cognitive and emotional development, and more. Authoritative yet accessible, From Neurons to Neighborhoods presents the evidence about "brain wiring" and how kids learn to speak, think, and regulate their behavior. It examines the effect of the climate-family, child care, community-within which the child grows.

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From Neurons to Neighborhoods: The Science of Early Childhood Development

A Treatise on the Family. G. S. Becker. Cambridge, MA: Harvard University Press. 1981. Gary Becker is one of the most famous and influential economists of the second half of the 20th century, a fervent contributor to and expounder of the University of Chicago free-market philosophy, and winner of the 1992 Nobel Prize in economics. Although any book with the word "treatise" in its title is clearly intended to have an impact, one coming from someone as brilliant and controversial as Becker certainly had such a lofty goal. It has received many article-length reviews in several disciplines (Ben-Porath, 1982; Bergmann, 1995; Foster, 1993; Hannan, 1982), which is one measure of its scholarly importance, and yet its impact is, I think, less than it may have initially appeared, especially for scholars with substantive interests in the family. This book is, its title notwithstanding, more about economics and the economic approach to behavior than about the family. In the first sentence of the preface, Becker writes "In this book, I develop an economic or rational choice approach to the family." Lest anyone accuse him of focusing on traditional (i.e., material) economics topics, such as family income, poverty, and labor supply, he immediately emphasizes that those topics are not his focus. "My intent is more ambitious: to analyze marriage, births, divorce, division of labor in households, prestige, and other non-material behavior with the tools and framework developed for material behavior." Indeed, the book includes chapters on many of these issues. One chapter examines the principles of the efficient division of labor in households, three analyze marriage and divorce, three analyze various child-related issues (fertility and intergenerational mobility), and others focus on broader family issues, such as intrafamily resource allocation. His analysis is not, he believes, constrained by time or place. His intention is "to present a comprehensive analysis that is applicable, at least in part, to families in the past as well as the present, in primitive as well as modern societies, and in Eastern as well as Western cultures." His tone is profoundly conservative and utterly skeptical of any constructive role for government programs. There is a clear sense of how much better things were in the old days of a genderbased division of labor and low market-work rates for married women. Indeed, Becker is ready and able to show in Chapter 2 that such a state of affairs was efficient and induced not by market or societal discrimination (although he allows that it might exist) but by small underlying household productivity differences that arise primarily from what he refers to as "complementarities" between caring for young children while carrying another to term. Most family scholars would probably find that an unconvincingly simple explanation for a profound and complex phenomenon. What, then, is the salient contribution of Treatise on the Family? It is not literally the idea that economics could be applied to the nonmarket sector and to family life because Becker had already established that with considerable success and influence. At its core, microeconomics is simple, characterized by a belief in the importance of prices and markets, the role of self-interested or rational behavior, and, somewhat less centrally, the stability of preferences. It was Becker's singular and invaluable contribution to appreciate that the behaviors potentially amenable to the economic approach were not limited to phenomenon with explicit monetary prices and formal markets. Indeed, during the late 1950s and throughout the 1960s, he did undeniably important and pioneering work extending the domain of economics to such topics as labor market discrimination, fertility, crime, human capital, household production, and the allocation of time. Nor is Becker's contribution the detailed analyses themselves. Many of them are, frankly, odd, idiosyncratic, and off-putting. …

A Treatise on the Family

Recent research consistently reports that persistent poverty has more detrimental effects on IQ, school achievement, and socioemotional functioning than transitory poverty, with children experiencing both types of poverty generally doing less well than never-poor children. Higher rates of perinatal complications, reduced access to resources that buffer the negative effects of perinatal complications, increased exposure to lead, and less home-based cognitive stimulation partly account for diminished cognitive functioning in poor children. These factors, along with lower teacher expectancies and poorer academic-readiness skills, also appear to contribute to lower levels of school achievement among poor children. The link between socioeconomic disadvantage and children's socioemotional functioning appears to be mediated partly by harsh, inconsistent parenting and elevated exposure to acute and chronic stressors. The implications of research findings for practice and policy are considered.

Socioeconomic disadvantage and child development

Policy-makers are considering large-scale programs aimed at self-control to improve citizens’ health and wealth and reduce crime. Experimental and economic studies suggest such programs could reap benefits. Yet, is self-control important for the health, wealth, and public safety of the population? Following a cohort of 1,000 children from birth to the age of 32 y, we show that childhood self-control predicts physical health, substance dependence, personal finances, and criminal offending outcomes, following a gradient of self-control. Effects of children's self-control could be disentangled from their intelligence and social class as well as from mistakes they made as adolescents. In another cohort of 500 sibling-pairs, the sibling with lower self-control had poorer outcomes, despite shared family background. Interventions addressing self-control might reduce a panoply of societal costs, save taxpayers money, and promote prosperity.

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A gradient of childhood self-control predicts health, wealth, and public safety

The benefits of Head Start are under increased scrutiny as Congress debates its reauthorization. How effective is Head Start, and how can it be improved? We provide a current overview and critical evaluation of Head Start research and discuss implications of this research with an eye toward informing debate. There has been a good deal of controversy over whether Head Start produces lasting benefits, dating back to its early years. Our review finds mixed, but generally positive, evidence regarding Head Start’s long-term benefits. Although studies typically find that increases in IQ fade out over time, many other studies also find decreases in grade retention and special education placements. Sustained increases in school achievement are sometimes found, but in other cases flawed research methods produce results that mimic fade-out. In recent years, the federal government has funded large-scale evaluations of Head Start and Early Head Start. Results from the Early Head Start evaluation are particularly informative, as study participants were randomly assigned to either the Early Head Start group or a control group. Early Head Start demonstrated modest improvements in children’s development and parent beliefs and behavior. The ongoing National Head Start Impact Study, which is also using random assignment, should yield additional insight into Head Start’s effectiveness. We conclude with suggestions for future research. key words: early education, Head Start, long-term benefits, policy

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Head start's lasting benefits

The Perry Preschool Project is a study of 123 black youths from families of low socioeconomic status, who were at risk of failing in school. The purpose of the study is to explore the long-term effects on these young people of participation versus nonparticipation in a program of high quality early childhood education. Results to age 19 indicate lasting beneficial effects of preschool education in improving scholastic placement and achievement during the school years; in decreasing delinquency and crime, the use of welfare assistance, and the incidence of teenage pregnancy; and in increasing the rates of high school graduation, enrollment in postsecondary programs, and employment. These findings, and findings from other studies of similar children, apply to children at risk of scholastic failure for sociocultural reasons.

Effects of the Perry Preschool Program on Youths Through Age 19: A Summary

Economic costs and benefits of early intervention.

Targeted or universal pre-K? Direct instruction or learning through play? These and other debates are heating up as more and more young children across the country gain access to pre-K programs. Now there's a single volume that spotlights today's most urgent pre-K debates, explores each one from all sides, and paves the way for sound, educated decision-making. Edited by a founder of Head Start and two other highly respected experts, this forward-thinking book gathers a who's who of more than 40 leading thinkers in early childhood education for a rigorous examination of the most-debated pre-K issues. In a clear and compelling point-counterpoint format, this book gives current and future decision-makers multifaceted perspectives on critical questions: Should pre-K be targeted or universal? What kind of teacher preparation should be required, in terms of credentials and education? When should pre-K services be provided and for how long? Where should pre-K be provided-in public schools only or in other early childhood programs? What should the primary focus of instruction be-- academics or the whole child? Should pre-K be structured around direct instruction or learning through play? How can we ensure quality and accountability in pre-K programs? Readers will also get a helpful synthesis of the major themes of the pre-K debate, investigate lessons learned from model programs in two states (New Jersey and Oklahoma), and identify key issues for future research and debate, including education policies for English language learners and children with special needs. Whether used as a reference or a preservice text, this landmark book will prepare early childhood administrators, policy makers, and researchers to make informed decisions about the future of preK-- so all young children will have the best chance at school success.

The Pre-K Debates: Current Controversies and Issues.

Participation in early care and education (ECE) programs has become the norm for this nation’s three- and four-year olds. Public investments in such programs have been promoted on the grounds that they can produce high rates of return in the form of academic outcomes, greater employment rates, and reduced crime. Yet, potential gains are not always realized, as benefits and costs depend on who is served by the program, the activities provided, and the resources required to produce such activities. This paper reviews the basis for claims related to the costs, benefits, and long-term effects of ECE programs, including effects on children’s learning and development and parental earnings. It also summarizes what is known about the extent to which variations in child and program characteristics and the community context alter the magnitude of benefits from ECE, as well as policy choices that could increase educational gains and other benefits, thereby increasing the return on public investments.

W. Steven Barnett

Papers

Head start's lasting benefits

Effects of the Perry Preschool Program on Youths Through Age 19: A Summary

Economic costs and benefits of early intervention.

The Pre-K Debates: Current Controversies and Issues.

Costs, Benefits, and Long-Term Effects of Early Care and Education Programs: Recommendations and Cautions for Community Developers