Rapid change in drift of the Australian plate records collision with Ontong Java plateau

The subduction of oceanic plateaux, which contain extraordinarily thick basaltic crust and are the marine counterparts of continental flood-basalt provinces, is an important factor in many current models of plate motion and provides a potential mechanism for triggering plate reorganization. To evaluate such models, it is essential to decipher the history of the collision between the largest and thickest of the world's oceanic plateaux, the Ontong Java plateau, and the Australian plate, but this has been hindered by poor constraints for the arrival of the plateau at the Melanesian trench. Here we present (40)Ar-(39)Ar geochronological data on hotspot volcanoes in eastern Australian that reveal a strong link between collision of the Greenland-sized Ontong Java plateau with the Melanesian arc and motion of the Australian plate. The new ages define a short-lived period of reduced northward plate motion between 26 and 23 Myr ago, coincident with an eastward offset in the contemporaneous tracks of seamount chains in the Tasman Sea east of Australia. These features record a brief westward deflection of the Australian plate as the plateau entered and choked the Melanesian trench 26 Myr ago. From 23 Myr ago, Australia returned to a rapid northerly trajectory at roughly the same time that southwest-directed subduction began along the Trobriand trough. The timing and brevity of this collisional event correlate well with offsets in hotspot seamount tracks on the Pacific plate, including the archetypal Hawaiian chain, and thus provide strong evidence that immense oceanic plateaux, like the Ontong Java, can contribute to initiating rapid change in plate boundaries and motions on a global scale.     

Distinct epigenetic changes in the stromal cells of breast cancers

Increasing evidence suggests that changes in the cellular microenvironment contribute to tumorigenesis, but the molecular basis of these alterations is not well understood. Although epigenetic modifications of the neoplastic cells in tumors have been firmly implicated in tumorigenesis, it is not known whether epigenetic modifications occur in the non-neoplastic stromal cells. To address this question in an unbiased and genome-wide manner, we developed a new method, methylation-specific digital karyotyping, and applied it to epithelial and myoepithelial cells, stromal fibroblasts from normal breast tissue, and in situ and invasive breast carcinomas. Our analyses showed that distinct epigenetic alterations occur in all three cell types during breast tumorigenesis in a tumor stage- and cell type-specific manner, suggesting that epigenetic changes have a role in the maintenance of the abnormal cellular microenvironment in breast cancer.     

基于历史视角的当代自画像

从历史的视角研究当代自画像，就能发现自画像创作以及风格的演变过程。早期自画像并非艺术家自觉的产物，因为那时的艺术家是有钱人的雇工。随后自画像走向自觉。艺术家为了招徕顾客，将自画像作品作为技艺高超的证据。19-20世纪，自画像开始表达艺术家的心理活动；21世纪，自画像成为真实记录艺术家思想的一种特殊方式。     

Luddite Interventions: on the Poetics of Catastrophe and the Art of Criticism

As an art theoretician, and as a father, I focus on the social and political consequences of Vanderbeeken’s postmodernist negative theology. I express doubts about the relevance of a poetics of catastrophe that conflates any possible alternative to the alleged technocracy under the sign of the simulacrum. To my opinion, the discourse about the virtual and the real are in a deadlock. Following the lead of American novelist Thomas Pynchon, I rephrase these critical doubts in Luddite terms: should we imagine a counterattack as radical as the alleged dystopian nightmare dreamed up and sketched out by Vanderbeeken? I try to show that this line of thinking risks to result in a bold and speculative logic where ethical nuance collapses and, ultimately, the relationship between art, theory and the social culture is reduced to metaphorical analogy. To make this point I retake a critical, phenomenologically inspired reaction by Vivian Sobchack to Baudrillard’s account of Crash, J.G. Ballard’s controversial novel on techno-fetishism. My argument is that the scar that marks Sobchack’s ‘technobody’ might here stand for an alternative that approaches our technological condition not as a discursive machine but as a social pragmatics with deep ethical implications.     

Le degré de polymérisation de l'amylose,de l'amylopectine et du glycogène

Summary A colorimetric method based on the reducing power of the aldehydic end group has been developed in order to determine the M. W. of polysaccharides. It has been found that corn amylose contains chain molecules of much higher degree of polymerization than potato amylose.     

Intrusion triggering of the 2010 Eyjafjallajökull explosive eruption

Gradual inflation of magma chambers often precedes eruptions at highly active volcanoes. During such eruptions, rapid deflation occurs as magma flows out and pressure is reduced. Less is known about the deformation style at moderately active volcanoes, such as Eyjafjallaj?kull, Iceland, where an explosive summit eruption of trachyandesite beginning on 14 April 2010 caused exceptional disruption to air traffic, closing airspace over much of Europe for days. This eruption was preceded by an effusive flank eruption of basalt from 20 March to 12 April 2010. The 2010 eruptions are the culmination of 18?years of intermittent volcanic unrest. Here we show that deformation associated with the eruptions was unusual because it did not relate to pressure changes within a single magma chamber. Deformation was rapid before the first eruption (>5?mm per day after 4 March), but negligible during it. Lack of distinct co-eruptive deflation indicates that the net volume of magma drained from shallow depth during this eruption was small; rather, magma flowed from considerable depth. Before the eruption, a ～0.05?km(3) magmatic intrusion grew over a period of three months, in a temporally and spatially complex manner, as revealed by GPS (Global Positioning System) geodetic measurements and interferometric analysis of satellite radar images. The second eruption occurred within the ice-capped caldera of the volcano, with explosivity amplified by magma-ice interaction. Gradual contraction of a source, distinct from the pre-eruptive inflation sources, is evident from geodetic data. Eyjafjallaj?kull's behaviour can be attributed to its off-rift setting with a 'cold' subsurface structure and limited magma at shallow depth, as may be typical for moderately active volcanoes. Clear signs of volcanic unrest signals over years to weeks may indicate reawakening of such volcanoes, whereas immediate short-term eruption precursors may be subtle and difficult to detect.