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

We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.

Random graphs

A review of the geologic history of the Himalayan-Tibetan orogen suggests that at least 1400 km of north-south shortening has been absorbed by the orogen since the onset of the Indo-Asian collision at about 70 Ma. Significant crustal shortening, which leads to eventual construction of the Cenozoic Tibetan plateau, began more or less synchronously in the Eocene (50–40 Ma) in the Tethyan Himalaya in the south, and in the Kunlun Shan and the Qilian Shan some 1000–1400 km in the north. The Paleozoic and Mesozoic tectonic histories in the Himalayan-Tibetan orogen exerted a strong control over the Cenozoic strain history and strain distribution. The presence of widespread Triassic flysch complex in the Songpan-Ganzi-Hoh Xil and the Qiangtang terranes can be spatially correlated with Cenozoic volcanism and thrusting in central Tibet. The marked difference in seismic properties of the crust and the upper mantle between southern and central Tibet is a manifestation of both Mesozoic and Cenozoic tectonics. The form...

Geologic Evolution of the Himalayan-Tibetan Orogen

N G van Kampen 1981 Amsterdam: North-Holland xiv + 419 pp price Dfl 180 This is a book which, at a lower price, could be expected to become an essential part of the library of every physical scientist concerned with problems involving fluctuations and stochastic processes, as well as those who just enjoy a beautifully written book. It provides an extensive graduate-level introduction which is clear, cautious, interesting and readable.

https://iopscience.iop.org/article/10.1088/0031-9112/34/4/040/pdf

Stochastic Processes in Physics and Chemistry

Convective removal of lower lithosphere beneath the Tibetan Plateau can account for a rapid increase in the mean elevation of the Tibetan Plateau of 1000 m or more in a few million years. Such uplift seems to be required by abrupt tectonic and environmental changes in Asia and the Indian Ocean in late Cenozoic time. The composition of basaltic volcanism in northern Tibet, which apparently began at about 13 Ma, implies melting of lithosphere, not asthenosphere. The most plausible mechanism for rapid heat transfer to the midlithosphere is by convective removal of deeper lithosphere and its replacement by hotter asthenosphere. The initiation of normal faulting in Tibet at about 8 (± 3) Ma suggests that the plateau underwent an appreciable increase in elevation at that time. An increase due solely to the isostatic response to crustal thickening caused by India's penetration into Eurasia should have been slow and could not have triggered normal faulting. Another process, such as removal of relatively cold, dense lower lithosphere, must have caused a supplemental uplift of the surface. Folding and faulting of the Indo-Australian plate south of India, the most prominent oceanic intraplate deformation on Earth, began between about 7.5 and 8 Ma and indicates an increased north-south compressional stress within the Indo-Australian plate. A Tibetan uplift of only 1000 m, if the result of removal of lower lithosphere, should have increased the compressional stress that the plateau applies to India and that resists India's northward movement, from an amount too small to fold oceanic lithosphere, to one sufficient to do so. The climate of the equatorial Indian Ocean and southern Asia changed at about 6–9 Ma: monsoonal winds apparently strengthened, northern Pakistan became more arid, but weathering of rock in the eastern Himalaya apparently increased. Because of its high altitude and lateral extent, the Tibetan Plateau provides a heat source at midlatitudes that should oppose classical (symmetric) Hadley circulation between the equator and temperate latitudes and that should help to drive an essentially opposite circulation characteristic of summer monsoons. For the simple case of axisymmetric heating (no dependence on longitude) of an atmosphere without dissipation, theoretical analyses by Hou, Lindzen, and Plumb show that an axisymmetric heat source displaced from the equator can drive a much stronger meridianal (monsoonlike) circulation than such a source centered on the equator, but only if heating exceeds a threshold whose level increases with the latitude of the heat source. Because heating of the atmosphere over Tibet should increase monotonically with elevation of the plateau, a modest uplift (1000–2500 m) of Tibet, already of substantial extent and height, might have been sufficient to exceed a threshold necessary for a strong monsoon. The virtual simultaneity of these phenomena suggests that uplift was rapid: approximately 1000 m to 2500 m in a few million years. Moreover, nearly simultaneously with the late Miocene strengthening of the monsoon, the calcite compensation depth in the oceans dropped, plants using the relatively efficient C4 pathway for photosynthesis evolved rapidly, and atmospheric CO2 seems to have decreased, suggesting causal relationships and positive feedbacks among these phenomena. Both a supplemental uplift of the Himalaya, the southern edge of Tibet, and a strengthened monsoon may have accelerated erosion and weathering of silicate rock in the Himalaya that, in turn, enhanced extraction of CO2 from the atmosphere. Thus these correlations offer some support for links between plateau uplift, a downdrawing of CO2 from the atmosphere, and global climate change, as proposed by Raymo, Ruddiman, and Froehlich. Mantle dynamics beneath mountain belts not only may profoundly affect tectonic processes near and far from the belts, but might also play an important role in altering regional and global climates.

Mantle dynamics, uplift of the Tibetan Plateau, and the Indian Monsoon

https://comptes-rendus.academie-sciences.fr/geoscience/item/10.5802/crgeos.174.pdf

Scaling of fractured rock flow. Proposition of indicators for selection of DFN based flow models

The present work is part of a more global study implying the Lena river (Siberia) evolution under climate change in collaboration with the IDES laboratory (Interaction et Dynamique des Environnements de Surface at Orsay University, see e.g. Costard and Gautier, 2007) where the study of the system involves a threefold approach including in situ field work (near Yakutsk), experimental modeling (in a cold room at Orsay University) and numerical modeling.

/pdf/development-of-a-coupled-thermo-hydro-model-and-study-of-the-5bh264h3ea.pdf

Development of a coupled Thermo-Hydro model and study of the evolution of a river-valley-talik system in the context of climate change

. The Alps Mountains play a major role in the water cycle at a regional scale in Europe. This mountain range acts as the ‘water tower’ of Europe by storing large volumes of ice and snow, and by regulating the runoff of the rivers constituting freshwater reservoirs of paramount importance for the biodiversity and human activity. Located in the French Southern Alps, 15 the Cerveyrette valley and a high-altitude ( ≈ 2000 m) swampy plain constitute a watershed of about 100 km 2 . From August 2011 to July 2013, water samples were collected monthly from the Cerveyrette river upstream of the Cervières village (elevation = 1620 m) located in the Upper Durance catchment area. Apparent cyclicality in d 2 H and d 18 O of the river waters documented over these two years partly reflect seasonal variations in the isotopic compositions of precipitations that mainly occur as snow accumulating at altitudes ranging from ≈ 1700 m to 3300 m. The estimated time lag of three to four months 20 between summer precipitations and their sampling in the Cerveyrette river at the discharge point of the watershed is interpreted to integrate both the mean transfer time of the water discharge and the rate of melting of the snow cover. Here, we show that the transfer time from mountain-accumulated snow toward the low-altitude cultivated areas (Provence) is a sensitive key variable responding to the current climate warming. Indeed, a lowering of the snow cover surface is expected to reduce the buffer effect of snow compared to rainfall, and to decrease the time period during which the discharge rate of 25 the Durance river is large enough for constituting sizable water resources. Understanding and modeling water transit times in nival dominated watersheds are consequently critical to evaluate the impact of the ongoing climate warming on water circulation and resources in the Alps and downstream including the case of mitigation actions. We show the importance the the as a sensitive key variable a and a reduced effect compared This study explores a way to quantify the influence of climate change on this wide-area transfer time. Understanding and modeling water transit times will be useful to estimate 35 the real impact of the ongoing climate changes on water circulation and water resources in the Alps and downstream including the case of mitigation actions.

Seasonal d 2 H and d 18 O changes in river water from a high-altitude humid plain of the southern Alps (Cervières, France): tracking the transit time through a watershed

In natural rivers, sediment heterogeneity and flow variability control the diversity of transport modes that occur. Although these different modes contribute to the total sediment transport, a law extending from bed load to suspended load that is, relevant for a wide range of sediment mixtures and flow conditions is lacking. Besides, a transport‐limited assumption is often made in modeling of fluvial morphodynamics and thus potentially misses under‐/over‐capacity regimes associated with a particular range of grain sizes and hydraulic conditions. We present a Multi Grain‐Size Total Load model based on widely accepted concepts of sediment transport and developed within the transport length framework in combination with an erosion‐deposition formulation. The new transport length model captures the diversity of transport modes as a physical continuum. Transport capacities for single or bimodal grain sizes are reasonably predicted when compared to published data and scale with the bed shear stress through a continuously varying exponent linked to the characteristic transport height. Modeled transport lengths extend over several orders of magnitude at given flow conditions. Extremely long distances suggest that suspended transport is probably never at capacity. The model can be extended to populations of various grain sizes with a threshold of motion corrected from hiding‐exposure. However, further experimental constraints are needed to better describe entrainment and saltation in strongly heterogeneous bed load transport. The new theoretical formalism we introduce paves the way for a Multi Grain‐Size Total Load Sediment Transport model that includes the variety of transport modes in both non‐stationary and stationary regimes.

Multi Grain‐Size Total Sediment Load Model Based on the Disequilibrium Length

We derive the relationships that link the general elastic properties of rock masses to the geometrical properties of fracture networks, with a special emphasis to the case of frictional crack surfa...

Philippe Davy

Papers

Scaling of fractured rock flow. Proposition of indicators for selection of DFN based flow models

Development of a coupled Thermo-Hydro model and study of the evolution of a river-valley-talik system in the context of climate change

Seasonal d 2 H and d 18 O changes in river water from a high-altitude humid plain of the southern Alps (Cervières, France): tracking the transit time through a watershed

Multi Grain‐Size Total Sediment Load Model Based on the Disequilibrium Length

Elastic properties of fractured rock masses