Brittle-Ductile Rheological Behavior in Subduction Zones: Effects of Strength Ratio Between Strong and Weak Phases in a Bi-Phase System

The brittle-ductile rheological behavior in subduction zones is commonly proposed to explain deep transient slips. Generally observed at large scales in tectonic “mélanges”, here we show that it is also observed at the grain scale in exhumed blueschist metagabbros. In these rocks, petrologic and microstructural observations show a bi-phase material constituted by strong microfractured magmatic pyroxene clasts located in a weak and ductile lawsonite-rich metamorphic matrix. To constrain the mechanical conditions allowing the brittle deformation of a clast in a ductile matrix, we used two-dimensional simple shear numerical experiments. Results show four behaviors: (a) entirely brittle; (b) brittle-ductile with clast fracturing in a ductile matrix; (c) ductile-dominant with limited plastic deformation at clast edges; and (d) entirely ductile. We propose that the conditions of the brittle-ductile behavior, commonly associated with deep transient slips, are controlled by the strength ratio between the strong brittle phase and the weak ductile phase

Impaired Embryonic Development in Mice Overexpressing the RNA-Binding Protein TIAR

TIA-1-related (TIAR) protein is a shuttling RNA-binding protein involved in several steps of RNA metabolism. While in the nucleus TIAR participates to alternative splicing events, in the cytoplasm TIAR acts as a translational repressor on specific transcripts such as those containing AU-Rich Elements (AREs). Due to its ability to assemble abortive pre-initiation complexes coalescing into cytoplasmic granules called stress granules, TIAR is also involved in the general translational arrest observed in cells exposed to environmental stress. However, the in vivo role of this protein has not been studied so far mainly due to severe embryonic lethality upon tiar invalidation.Journal ArticleResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe

From ductile to brittle: evolution and localization of deformation below a crustal detachment (Tinos, Cyclades, Greece)

International audienceThe Cycladic Oligo-Miocene detachment of Tinos island is an example of a flat-lying extensional shear zone evolving into a low-angle brittle detachment. A clear continuum of extensional strain from ductile to brittle regime is observed in the footwall. The main brittle structures marking extension are shallow- and steeply dipping normal faults associated with subvertical extensional joints and veins. The earliest brittle structures are lowangle normal faults which commonly superimpose on, and reactivate, earlier (precursory) ductile shear bands, but newly formed low-angle normal faults could also be observed. Low-angle normal faults are cut by late steeply dipping normal faults. The inversion of fault slip data collected within, and away from, the main detachment zone shows that the direction of the minimum stress axis is strictly parallel to the NE-SW stretching lineation and that the maximum principal stress axis remained subvertical during the whole brittle evolution, in agreement with the subvertical attitude of veins throughout the island. The high angle of s1 to the main detachment suggests that the detachment was weak. This observation, together with the presence of a thick layer of cataclasites below the main detachment and the kinematic continuum from ductile to brittle, leads us to propose a kinematic model for the formation of the detachment. Boudinage at the crustal scale induces formation, near the brittle-ductile transition, of ductile shear zones near the edges of boudins. Shear zones are progressively exhumed and replaced by shallowdipping cataclastic shear zones when they reached the brittle field. Most of the displacement is achieved through cataclastic flow in the upper crust and only the last increment of strain gives rise to the formation of brittle faults. The formation of the low-angle brittle detachment is thus ''prepared'' by the ductile shear zone and the cataclasites and favored by the circulation of surface-derived fluids in the shear zone

iCLIP Predicts the Dual Splicing Effects of TIA-RNA Interactions

Transcriptome-wide analysis of protein-RNA interactions predicts the dual splicing effects of TIA proteins, showing that their local enhancing function is associated with diverse distal splicing silencing effects

Different modes of interaction by TIAR and HuR with target RNA and DNA

TIAR and HuR are mRNA-binding proteins that play important roles in the regulation of translation. They both possess three RNA recognition motifs (RRMs) and bind to AU-rich elements (AREs), with seemingly overlapping specificity. Here we show using SPR that TIAR and HuR bind to both U-rich and AU-rich RNA in the nanomolar range, with higher overall affinity for U-rich RNA. However, the higher affinity for U–rich sequences is mainly due to faster association with U-rich RNA, which we propose is a reflection of the higher probability of association. Differences between TIAR and HuR are observed in their modes of binding to RNA. TIAR is able to bind deoxy-oligonucleotides with nanomolar affinity, whereas HuR affinity is reduced to a micromolar level. Studies with U-rich DNA reveal that TIAR binding depends less on the 2′-hydroxyl group of RNA than HuR binding. Finally we show that SAXS data, recorded for the first two domains of TIAR in complex with RNA, are more consistent with a flexible, elongated shape and not the compact shape that the first two domains of Hu proteins adopt upon binding to RNA. We thus propose that these triple-RRM proteins, which compete for the same binding sites in cells, interact with their targets in fundamentally different ways

Post-transcriptional control during chronic inflammation and cancer: a focus on AU-rich elements

A considerable number of genes that code for AU-rich mRNAs including cytokines, growth factors, transcriptional factors, and certain receptors are involved in both chronic inflammation and cancer. Overexpression of these genes is affected by aberrations or by prolonged activation of several signaling pathways. AU-rich elements (ARE) are important cis-acting short sequences in the 3′UTR that mediate recognition of an array of RNA-binding proteins and affect mRNA stability and translation. This review addresses the cellular and molecular mechanisms that are common between inflammation and cancer and that also govern ARE-mediated post-transcriptional control. The first part examines the role of the ARE-genes in inflammation and cancer and sequence characteristics of AU-rich elements. The second part addresses the common signaling pathways in inflammation and cancer that regulate the ARE-mediated pathways and how their deregulations affect ARE-gene regulation and disease outcome

De La Fabrique Du Réel (Apocalyptique) Dans La Bande Dessinée Beyrouth Bye Bye... De Barrack Rima

This article examines the Lebanese bande dessinée, Beyrouth bye bye... (2015) by Barrack Rima, through the lens of anticipation narrative. Set in a dystopic place where ninja turtles cross path with crocodiles, censors and refugees, and in which the proliferation of trash threatens to drown all citizens, the characters are gradually expelled from the story and from the Lebanese capital, whose future the reader is invited to (re)consider. Rima’s sequential work, this article contends, reflects on the future of the Lebanese society and space. It also reflects on the modalities of representation and transmission of the reality it depicts. As such it is a work ‘engagé’ that tries to untangle the components of an apocalyptic future. The work becomes the receptacle of collective memory and history. While increasing awareness, it calls for a mobilization of civil society and works as an agent of socio-political action

Des Féminismes Du Sud Dans Bilqiss De Saphia Azzeddine

In the current social climate of an increasingly normalized Islamophobia, representations of Islam and Muslim women are as problematic as ever. This is partly due to the risk run by any cultural production dealing with the patriarchy and women\u27s oppression in the Arab-muslim world of being instrumentalized. Accordingly, any such production must be considered alongside questions of its intended consumption or its possible complicity with the dominant order. With this in mind, the article examines Saphia Azzeddine\u27s last novel, Bilqiss. It analyzes the literary strategies the author deploys in order to counter expectations about Muslim women from Western readers, and in particular readers from the Hexagon. We contend that Azzeddine\u27s refutation of her characters\u27 positions, which are often extreme to the point of caricature, allows her to develop a conversation around the so-called contemporary confrontations between East and West, forcing her readers to move beyond the sensationalized representations and the problematic interest Islam continues to generate in the West

Unreading Beirut In The Age Of Disaster Capitalism: Jorj Abou Mhaya’s Madinah Mujawirah Lil Ard

This essay examines how Jorg Abou Mhaya’s Madinah Mujawirah lil Ard [City Neighbouring the Earth] depicts a series of crucial ruptures in traditional collective identities, which are connected directly to emerging global realities. Mhaya’s Madinah reflects on the political, economic, and social (dis)order in contemporary Lebanon and critiques the unsettling transformations of its capital, Beirut. Carefully tailored to be both universal and phantasmagoric, Mhaya’s Beirut embodies the extent to which the hegemonic restructuring forces of neo-liberalisation have moulded the planet into an unfathomable and illegible referent. We argue here that the aesthetic strategies of Mhaya draw at once from hyper-realism and science fiction in order to evoke life as shaped by the aftermath of ‘disaster capitalism’: rational representations of lived realities seem elusive, and realist attempts to make sense of space, society, politics, and the present time appear destined to fail. In a country where changes are happening fast, reality tends to appear stranger than fiction, and comprehending it seems an impossible endeavour. The graphic novel thus mixes genres in order to make up for the aporia of discourse on life in the neo-liberal era