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

The development of this
review article has evolved from work carried out by an international
team of the International Space Science Institute (ISSI),
Bern, Switzerland, and from work carried out under the auspices
of Scientific Committee on Solar Terrestrial Physics (SCOSTEP)
Climate and Weather of the Sun‐Earth System (CAWSES‐1).
The support of ISSI in providing workshop and meeting facilities
is acknowledged, especially support from Y. Calisesi and V. Manno.
SCOSTEP is acknowledged for kindly providing financial assistance
to allow the paper to be published under an open access
policy. L.J.G. was supported by the UK Natural Environment
Research Council (NERC) through their National Centre for Atmospheric
Research (NCAS) Climate program. K.M. was supported
by a Marie Curie International Outgoing Fellowship within the
6th European Community Framework Programme. J.L. acknowledges
support by the EU/FP7 program Assessing Climate Impacts
on the Quantity and Quality of Water (ACQWA, 212250) and from
the DFG Project Precipitation in the Past Millennium in Europe
(PRIME) within the Priority Program INTERDYNAMIK. L.H.
acknowledges support from the U.S. NASA Living With a Star
program. G.M. acknowledges support from the Office of Science
(BER), U.S. Department of Energy, Cooperative Agreement
DE‐FC02‐97ER62402, and the National Science Foundation. We
also wish to thank Karin Labitzke and Markus Kunze for supplying
an updated Figure 13, Andrew Heaps for technical support, and
Paul Dickinson for editorial support. Part of the research was
carried out under the SPP CAWSES funded by GFG. J.B. was
financially supported by NCCR Climate–Swiss Climate Research.

/pdf/solar-influences-on-climate-48ynhy9kuz.pdf

Solar influences on climate

This chapter assesses the causes of observed changes assessed in Chapters 2 to 5 and uses understanding of physical processes, climate models and statistical approaches. The chapter adopts the terminology for detection and attribution proposed by the IPCC good practice guidance paper on detection and attribution (Hegerl et al., 2010) and for uncertainty Mastrandrea et al. (2011). Detection and attribution of impacts of climate changes are assessed by Working Group II, where Chapter 18 assesses the extent to which atmospheric and oceanic changes influence ecosystems, infrastructure, human health and activities in economic sectors.

Detection and attribution of climate change: from global to regional

Prevailing opinion assigns the Tibetan Plateau a crucial role in shaping Asian climate, primarily by heating of the atmosphere over Tibet during spring and summer Accordingly, the growth of the plateau in geologic time should have written a signature on Asian paleoclimate Recent work on Asian climate, however, challenges some of these views The high Tibetan Plateau may affect the South Asian monsoon less by heating the overlying atmosphere than by simply acting as an obstacle to southward flow of cool, dry air The East Asian “monsoon” seems to share little in common with most monsoons, and its dynamics may be affected most by Tibet's lying in the path of the subtropical jet stream Although the growing plateau surely altered Asian climate during Cenozoic time, the emerging view of its role in present-day climate opens new challenges for interpreting observations of both paleoclimate and modern climate

/pdf/orographic-controls-on-climate-and-paleoclimate-of-asia-r9pi5noudu.pdf

Orographic controls on climate and paleoclimate of Asia: thermal and mechanical roles for the Tibetan Plateau.

Information from paleoclimate archives

A record from Wanxiang Cave, China, characterizes Asian Monsoon (AM) history over the past 1810 years. The summer monsoon correlates with solar variability, Northern Hemisphere and Chinese temperature, Alpine glacial retreat, and Chinese cultural changes. It was generally strong during Europe's Medieval Warm Period and weak during Europe's Little Ice Age, as well as during the final decades of the Tang, Yuan, and Ming Dynasties, all times that were characterized by popular unrest. It was strong during the first several decades of the Northern Song Dynasty, a period of increased rice cultivation and dramatic population increase. The sign of the correlation between the AM and temperature switches around 1960, suggesting that anthropogenic forcing superseded natural forcing as the major driver of AM changes in the late 20th century.

/pdf/a-test-of-climate-sun-and-culture-relationships-from-an-1810-4bejc5a8nt.pdf

A test of climate, sun, and culture relationships from an 1810-year Chinese cave record.

Interpretation of NO3− variability recorded in ice cores remains challenging as it can be lost from snow. Here, we present 60‐year records of NO3− and its isotopic composition (δ15N, δ18O, and Δ17O) in snow in central Antarctica, Dome A. In the upper ∼90 cm snowpack, variations in concentration and isotopic composition of NO3− are dominated by photolytic loss, and δ18O and Δ17O of NO3− are associated with the recycling of NOx to NO3− in the condensed phase driven by photolysis. In the deeper snowpack (∼1960–2000), we observe prolonged trends in concentration and isotopic composition of NO3−, which are best explained as enhanced snow NO3− photolysis due to long‐term decreasing total column ozone (TCO). That is, the prolonged period of trends in NO3− and its isotopes in extremely low snow accumulation sites such as Dome A relay information on variations in TCO and consequently surface solar ultraviolet radiation over time.

Snow Nitrate Isotopes in Central Antarctica Record the Prolonged Period of Stratospheric Ozone Depletion From ∼1960 to 2000

The study of the fabric and microstructure of ice at the shear margin of the Antarctic ice sheet is of great significance for understanding the ice flow and its contributions to sea level rise. In this study, twenty-three one-meter-long ice cores were drilled from blue ice areas at the shear margin of the Dalk Glacier, Antarctica. The ice fabric and microstructure of these ice cores are analyzed using a G50 fabric analyzer. This study shows that the shallow ice cores in this region present a cluster fabric as a consequence of shear stress. The grain size decreases following the direction of the ice flow towards the exposed bedrock at the end of the glacier, due to the blocking and squeezing by the bedrock. The formation mechanism of the shallow ice layers is that the ice from the original accumulation area flows here, lifted by the bedrock and shaped by the summer ablation and denudation. The basal ice at the shear margin of the Dalk Glacier is strongly rubbed by the bedrock and demonstrates a cluster fabric. The analysis of stable water isotopes shows a weak negative correlation between shallow ice fabric and stable water isotopes with depth. Bedrock topography and shear stress have a greater influence on grain microstructure among different ice cores over long distances at shear margins.

https://www.mdpi.com/2073-4441/15/4/728/pdf?version=1676193526

Spatial Variations of Fabric and Microstructure of Blue Ice Cores at the Shear Margin of Dalk Glacier, Antarctica

Recent studies have suggested that water isotopologues in snow pits from remote East Antarctica can be influenced by the input of stratospheric water, which has anomalously high 17O‐excess values. However, it remains unclear whether the 17O‐excess records preserved in snow and ice from this region can be used to reconstruct stratosphere‐troposphere exchange (STE). In this study, we present high‐resolution 17O‐excess records from two snow pits at Dome A, the highest point of the Antarctic ice sheet. The 17O‐excess records show a significant positive correlation with the strength of the Brewer‐Dobson circulation (BDC), the hemispheric‐scale troposphere‐stratosphere overturn circulation. Stronger BDC leads to more stratospheric water input over Antarctica and higher 17O‐excess, and vice versa. In addition, the 17O‐excess records also have a significant positive correlation with the Southern Annular Mode (SAM) index, because SAM modulates Antarctic precipitation, which has a dilution effect on the stratospheric water input. The 17O‐excess records do not show significant correlations with local temperature and relative humidity in the moisture source region. These results suggest the dominant effect of BDC on 17O‐excess and indicate the potential for using 17O‐excess records in ice cores from remote sites in East Antarctica for reconstructing long‐term variations of STE, and understanding their mechanisms and climate effects.

Chunlei An

Papers

A test of climate, sun, and culture relationships from an 1810-year Chinese cave record.

Snow Nitrate Isotopes in Central Antarctica Record the Prolonged Period of Stratospheric Ozone Depletion From ∼1960 to 2000

Spatial Variations of Fabric and Microstructure of Blue Ice Cores at the Shear Margin of Dalk Glacier, Antarctica

The Dominant Role of Brewer‐Dobson Circulation on 17O‐Excess Variations in Snow Pits at Dome A, Antarctica

A high-resolution refractory black carbon (rBC) record since 1932 deduced from the Chongce ice core, Tibetan plateau