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

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(12)61766-8.pdf

A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010

Identifying and quantifying planetary boundaries that must not be transgressed could help prevent human activities from causing unacceptable environmental change, argue Johan Rockstrom and colleagues.

/pdf/a-safe-operating-space-for-humanity-tynyc6i2kf.pdf

A safe operating space for humanity

Human alteration of Earth is substantial and growing. Between one-third and one-half of the land surface has been transformed by human action; the carbon dioxide concentration in the atmosphere has increased by nearly 30 percent since the beginning of the Industrial Revolution; more atmospheric nitrogen is fixed by humanity than by all natural terrestrial sources combined; more than half of all accessible surface fresh water is put to use by humanity; and about one-quarter of the bird species on Earth have been driven to extinction. By these and other standards, it is clear that we live on a human-dominated planet.

/pdf/human-domination-of-earth-s-ecosystems-5eevmqq987.pdf

Human Domination of Earth's Ecosystems

This paper describes the contents of the 2016 edition of the HITRAN molecular spectroscopic compilation. The new edition replaces the previous HITRAN edition of 2012 and its updates during the intervening years. The HITRAN molecular absorption compilation is composed of five major components: the traditional line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, infrared absorption cross-sections for molecules not yet amenable to representation in a line-by-line form, collision-induced absorption data, aerosol indices of refraction, and general tables such as partition sums that apply globally to the data. The new HITRAN is greatly extended in terms of accuracy, spectral coverage, additional absorption phenomena, added line-shape formalisms, and validity. Moreover, molecules, isotopologues, and perturbing gases have been added that address the issues of atmospheres beyond the Earth. Of considerable note, experimental IR cross-sections for almost 300 additional molecules important in different areas of atmospheric science have been added to the database. The compilation can be accessed through www.hitran.org. Most of the HITRAN data have now been cast into an underlying relational database structure that offers many advantages over the long-standing sequential text-based structure. The new structure empowers the user in many ways. It enables the incorporation of an extended set of fundamental parameters per transition, sophisticated line-shape formalisms, easy user-defined output formats, and very convenient searching, filtering, and plotting of data. A powerful application programming interface making use of structured query language (SQL) features for higher-level applications of HITRAN is also provided.

/pdf/the-hitran-2008-molecular-spectroscopic-database-1ud8clpej3.pdf

The HITRAN 2008 molecular spectroscopic database

This paper examines the transport of North American sulfur emissions across the North Atlantic Ocean to Europe. A review of available precipitation sulfate data from the North Atlantic and adjacent coastal regions yields a concentration field which is consistent with known source distributions and meteorological factors. The marine background precipitation excess sulfate concentration is found to be 6-8 μeq 1 -1 and [SO 4 = ] to decrease from >50 μeq 1 -1 with offshore flows at the North American east coast to 8-15 μeq 1 -1 with onshore flows at the European west coast. This decay is consistent with a distance constant of 2400 km and a residence time of ~80 h, and in turn, corresponds to a transatlantic flux of anthropogenic sulfur of 0.3-0.4 Tg a -1 . A second independent estimate, based on the application of a climatological dispersion model, which accounts for long-term average diffusion, wet and dry deposition, and SO 2 to SO 4 = transformation, yields a flux of North American anthropogenic sulfur at the European west coast of 0.2 Tg a -1 , in agreement with the first estimate. At the distance of the European west coast, North American anthropogenic emissions account for ca. 4 μeq S 1 -1 in precipitation-less than the marine background of 6-8 μeq 1 -1 , and much less than the annual average [SO 4 = ] value of ca. 30 μeq S 1 -1 appropriate for much of the coastal region. It is concluded that, on average, the amount of North American anthropogenic sulfur reaching Europe is small compared to that from other sources. DOI: 10.1111/j.1600-0889.1988.tb00208.x

The transatlantic transport of sulfur

Atmospheric Nitrogen Deposition to Coastal Estuaries and their Watersheds

Streamwater composition data obtained through periodic sampling of streams that support brook trout (Salvelinus fontinalis) in the mountains of western Virginia were examined for evidence of recovery from acidification during the 1988−2001 period. Measurements of sulfate deposition in precipitation indicate that sulfate deposition in the region declined approximately 40% between 1985 and 2000. While no significant regional trends in acid−base constituents were observed for the set (n = 65) of western Virginia study streams, significant regional trends were observed for a subset (n = 14) of streams in Shenandoah National Park (SNP). For the subset of SNP streams, the median increase in acid-neutralizing capacity (ANC) was 0.168 μequiv L-1 year-1 and the median decrease in sulfate concentration was −0.229 μequiv L-1 year-1. Although these trends are consistent with recovery from acidification, the degree of apparent recovery is small compared to estimates of historic acidification in SNP streams and much le...

Are brook trout streams in western Virginia and Shenandoah National Park recovering from acidification

Sediment cores from two remote lakes, Sagamore and Woods (Adirondack State Park, New York), were analyzed for lead. A marked increase was found in the top 10 cm of the sediment of both lakes. The effect of lake acidification on the release of lead from the sediments was determined in laboratory studies. Significant lead desorption (>5% of the total) only occurred at a pH 4.4, lead is not being released from the sediments.

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1982.27.1.0163

Lake acidification: Its effect on lead in the sediment of two Adirondack lakes1,1

The acidity of precipitation in rural, forested areas of the northeastern United States is dominated by the strong mineral acids: H2SO4 and HN03. Weak acids have a negligible effect on the measured acidity (pH) of precipitation. These conclusions are based on total acidity titrations and detailed analysis of organic and inorganic components in precipitation.

https://www.nrs.fs.fed.us/pubs/gtr/gtr_ne23/gtr_ne23_383.pdf

James N. Galloway

Papers

The transatlantic transport of sulfur

Atmospheric Nitrogen Deposition to Coastal Estuaries and their Watersheds

Are brook trout streams in western Virginia and Shenandoah National Park recovering from acidification

Lake acidification: Its effect on lead in the sediment of two Adirondack lakes1,1

Hydrogen ion speciation in the acid precipitation of the northeastern United States