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

Discriminant validity assessment has become a generally accepted prerequisite for analyzing relationships between latent variables. For variance-based structural equation modeling, such as partial least squares, the Fornell-Larcker criterion and the examination of cross-loadings are the dominant approaches for evaluating discriminant validity. By means of a simulation study, we show that these approaches do not reliably detect the lack of discriminant validity in common research situations. We therefore propose an alternative approach, based on the multitrait-multimethod matrix, to assess discriminant validity: the heterotrait-monotrait ratio of correlations. We demonstrate its superior performance by means of a Monte Carlo simulation study, in which we compare the new approach to the Fornell-Larcker criterion and the assessment of (partial) cross-loadings. Finally, we provide guidelines on how to handle discriminant validity issues in variance-based structural equation modeling.

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A new criterion for assessing discriminant validity in variance-based structural equation modeling

Episodes of population growth and decline leave characteristic signatures in the distribution of nucleotide (or restriction) site differences between pairs of individuals. These signatures appear in histograms showing the relative frequencies of pairs of individuals who differ by i sites, where i = 0, 1, .... In this distribution an episode of growth generates a wave that travels to the right, traversing 1 unit of the horizontal axis in each 1/2u generations, where u is the mutation rate. The smaller the initial population, the steeper will be the leading face of the wave. The larger the increase in population size, the smaller will be the distribution's vertical intercept. The implications of continued exponential growth are indistinguishable from those of a sudden burst of population growth Bottlenecks in population size also generate waves similar to those produced by a sudden expansion, but with elevated uppertail probabilities. Reductions in population size initially generate L-shaped distributions with high probability of identity, but these converge rapidly to a new equilibrium. In equilibrium populations the theoretical curves are free of waves. However, computer simulations of such populations generate empirical distributions with many peaks and little resemblance to the theory. On the other hand, agreement is better in the transient (nonequilibrium) case, where simulated empirical distributions typically exhibit waves very similar to those predicted by theory. Thus, waves in empirical distributions may be rich in information about the history of population dynamics.

/pdf/population-growth-makes-waves-in-the-distribution-of-4ccuwodprl.pdf

Population growth makes waves in the distribution of pairwise genetic differences.

I. the origin of species by means of natural selection

We explore the development of the Anthropocene, the current epoch in which humans and our societies have become a global geophysical force. The Anthropocene began around 1800 with the onset of industrialization, the central feature of which was the enormous expansion in the use of fossil fuels. We use atmospheric carbon dioxide concentration as a single, simple indicator to track the progression of the Anthropocene. From a preindustrial value of 270-275 ppm, atmospheric carbon dioxide had risen to about 310 ppm by 1950. Since then the human enterprise has experienced a remarkable explosion, the Great Acceleration, with significant consequences for Earth System functioning. Atmospheric CO2 concentration has risen from 310 to 380 ppm since 1950, with about half of the total rise since the preindustrial era occurring in just the last 30 years. The Great Acceleration is reaching criticality. Whatever unfolds, the next few decades will surely be a tipping point in the evolution of the Anthropocene.

/pdf/the-anthropocene-are-humans-now-overwhelming-the-great-2zf4ui77b8.pdf

The Anthropocene: are humans now overwhelming the great forces of Nature?

Since its publication in 1989, "The Human Career" has proved to be an indispensable tool in teaching human origins. This substantially revised third edition retains Richard G. Klein's innovative approach while showing how cumulative discoveries and analyses over the past ten years have significantly refined our knowledge of human evolution. Klein chronicles the evolution of people from the earliest primates through the emergence of fully modern humans within the past 200,000 years. His comprehensive treatment stresses recent advances in knowledge, including, for example, ever more abundant evidence that fully modern humans originated in Africa and spread from there, replacing the Neanderthals in Europe and equally archaic people in Asia. With its coverage of both the fossil record and the archaeological record over the 2.5 million years for which both are available, "The Human Career" demonstrates that human morphology and behavior evolved together. Throughout the book, Klein presents evidence for alternative points of view but does not hesitate to make his own position clear. In addition to outlining the broad pattern of human evolution, "The Human Career" details the kinds of data that support it. For the third edition, Klein has added numerous tables and a fresh citation system designed to enhance readability, especially for students. He has also included more than fifty new illustrations to help lay readers grasp the fossils, artifacts, and other discoveries on which specialists rely. With abundant references and hundreds of images, charts, and diagrams, this new edition is unparalleled in its usefulness for teaching human evolution.

https://www.jstor.org/stable/pdfplus/281642.pdf

The human career : human biological and cultural origins

What caused the extinction of so many animals at or near the end of the Pleistocene? Was it overkill by human hunters, the result of a major climatic change or was it just a part of some massive evolutionary turnover? Questions such as these have plagued scientists for over one hundred years and are still being heatedly debated today. Quaternary Extinctions presents the latest and most comprehensive examination of these questions. Geological Magazine-- ""May be regarded as a kind of standard encyclopedia for Pleistocene vertebrate paleontology for years to come."" American Scientist-- ""Should be read by paleobiologists, biologists, wildlife managers, ecologists, archeologists, and anyone concerned about the ongoing extinction of plants and animals."" Science-- ""Uncommonly readable and varied for watchers of paleontology and the rise of humankind."" Scientific American-- ""Represents a quantum leap in our knowledge of Pleistocene and Holocene palaeobiology...Many volumes on our bookshelves are destined to gather dust rather than attention. But not this one."" Nature-- ""Two strong impressions prevail when first looking into this epic compendium. One is the judicious balance of views that range over the whole continuum between monocausal, cultural, or environmental explanations. The second is that both the data base and theoretical sophistication of the protagonists in the debate have improved by a quantum leap since 1967."" American Anthropologist--

Quaternary extinctions : a prehistoric revolution

In growing numbers, archeologists are specializing in the analysis of excavated animal bones as clues to the environment and behavior of ancient peoples. This pathbreaking work provides a detailed discussion of the outstanding issues and methods of bone studies that will interest zooarcheologists as well as paleontologists who focus on reconstructing ecologies from bones. Because large samples of bones from archeological sites require tedious and time-consuming analysis, the authors also offer a set of computer programs that will greatly simplify the bone specialist's job. After setting forth the interpretive framework that governs their use of numbers in faunal analysis, Richard G. Klein and Kathryn Cruz-Uribe survey various measures of taxonomic abundance, review methods for estimating the sex and age composition of a fossil species sample, and then give examples to show how these measures and sex/age profiles can provide useful information about the past. In the second part of their book, the authors present the computer programs used to calculate and analyze each numerical measure or count discussed in the earlier chapters. These elegant and original programs, written in BASIC, can easily be used by anyone with a microcomputer or with access to large mainframe computers.

Richard G. Klein

Papers

The human career : human biological and cultural origins

Quaternary extinctions : a prehistoric revolution

The Analysis of Animal Bones from Archaeological Sites

The human career

The analysis of animal bones from archeological sites