scholarly journals Creep consolidation in land subsidence modelling; integrating geotechnical and hydrological approaches in a new MODFLOW package (SUB-CR)

Author(s):  
Henk Kooi ◽  
Gilles Erkens

Abstract. Creep and secondary consolidation are important phenomena in settlement caused by surface loads, but not commonly considered in land subsidence driven by groundwater extraction. To explore the role of creep in such settings, a new MODFLOW-2005 land subsidence package was developed that incorporates a creep formulation gleaned from geotechnical software. This formulation, which is based on the isotache concept, is an extension of, and incorporates the classical elastoplastic compression model of Terzaghi as a limiting case. The package is introduced, and results are presented of an application to a site in northern Jakarta. It is shown that the isotache model requires considerably higher overconsolidation levels of clays than the Terzaghi model, and that creep contributes to subsidence long after drawdown in pumped aquifers has stabilized, a phenomenon that is traditionally attributed to “hydrodynamic lag”.

2012 ◽  
Vol 21 (2) ◽  
pp. 223-243
Author(s):  
Irit Degani-Raz

The idea that Beckett investigates in his works the limits of the media he uses has been widely discussed. In this article I examine the fiction Imagination Dead Imagine as a limiting case in Beckett's exploration of limits at large and the limits of the media he uses in particular. Imagination Dead Imagine is shown to be the self-reflexive act of an artist who imaginatively explores the limits of that ultimate medium – the artist's imagination itself. My central aim is to show that various types of structural homologies (at several levels of abstraction) can be discerned between this poetic exploration of the limits of imagination and Cartesian thought. The homologies indicated here transcend what might be termed as ‘Cartesian typical topics’ (such as the mind-body dualism, the cogito, rationalism versus empiricism, etc.). The most important homologies that are indicated here are those existing between the role of imagination in Descartes' thought - an issue that until only a few decades ago was quite neglected, even by Cartesian scholars - and Beckett's perception of imagination. I suggest the use of these homologies as a tool for tracing possible sources of inspiration for Beckett's Imagination Dead Imagine.


Author(s):  
Alison Carrol

In 1918 the end of the First World War triggered the return of Alsace to France after almost fifty years of annexation into the German Empire. Enthusiastic crowds in Paris and Alsace celebrated the homecoming of the so-called lost province, but return proved far less straightforward than anticipated. The region’s German-speaking population demonstrated strong commitment to local cultures and institutions, as well as their own visions of return to France. As a result, the following two decades saw politicians, administrators, industrialists, cultural elites, and others grapple with the question of how to make Alsace French again. The answer did not prove straightforward; differences of opinion emerged both inside and outside the region, and reintegration became a fiercely contested process that remained incomplete when war broke out in 1939. The Return of Alsace to France examines this story. Drawing upon national, regional, and local archives, it follows the difficult process of Alsace’s reintegration into French society, culture, political and economic systems, and legislative and administrative institutions. It connects the microhistory of the region with the macro levels of national policy, international relations, and transnational networks, and with the cross-border flows of ideas, goods, people, and cultural products that shaped daily life in Alsace. Revealing Alsace to be a site of exchange between a range of interest groups with different visions of the region’s future, this book underlines the role of regional populations and cross-border interactions in forging the French Third Republic.


2020 ◽  
Vol 402 (1) ◽  
pp. 89-98
Author(s):  
Nathalie Meiser ◽  
Nicole Mench ◽  
Martin Hengesbach

AbstractN6-methyladenosine (m6A) is the most abundant modification in mRNA. The core of the human N6-methyltransferase complex (MTC) is formed by a heterodimer consisting of METTL3 and METTL14, which specifically catalyzes m6A formation within an RRACH sequence context. Using recombinant proteins in a site-specific methylation assay that allows determination of quantitative methylation yields, our results show that this complex methylates its target RNAs not only sequence but also secondary structure dependent. Furthermore, we demonstrate the role of specific protein domains on both RNA binding and substrate turnover, focusing on postulated RNA binding elements. Our results show that one zinc finger motif within the complex is sufficient to bind RNA, however, both zinc fingers are required for methylation activity. We show that the N-terminal domain of METTL3 alters the secondary structure dependence of methylation yields. Our results demonstrate that a cooperative effect of all RNA-binding elements in the METTL3–METTL14 complex is required for efficient catalysis, and that binding of further proteins affecting the NTD of METTL3 may regulate substrate specificity.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Anurag Kumar Sinha ◽  
Kristoffer Skovbo Winther

AbstractBacteria synthesize guanosine tetra- and penta phosphate (commonly referred to as (p)ppGpp) in response to environmental stresses. (p)ppGpp reprograms cell physiology and is essential for stress survival, virulence and antibiotic tolerance. Proteins of the RSH superfamily (RelA/SpoT Homologues) are ubiquitously distributed and hydrolyze or synthesize (p)ppGpp. Structural studies have suggested that the shift between hydrolysis and synthesis is governed by conformational antagonism between the two active sites in RSHs. RelA proteins of γ-proteobacteria exclusively synthesize (p)ppGpp and encode an inactive pseudo-hydrolase domain. Escherichia coli RelA synthesizes (p)ppGpp in response to amino acid starvation with cognate uncharged tRNA at the ribosomal A-site, however, mechanistic details to the regulation of the enzymatic activity remain elusive. Here, we show a role of the enzymatically inactive hydrolase domain in modulating the activity of the synthetase domain of RelA. Using mutagenesis screening and functional studies, we identify a loop region (residues 114–130) in the hydrolase domain, which controls the synthetase activity. We show that a synthetase-inactive loop mutant of RelA is not affected for tRNA binding, but binds the ribosome less efficiently than wild type RelA. Our data support the model that the hydrolase domain acts as a molecular switch to regulate the synthetase activity.


2021 ◽  
Vol 1 ◽  
pp. 141-150
Author(s):  
Honorine Harlé ◽  
Pascal Le Masson ◽  
Benoit Weil

AbstractIn industry, there is at once a strong need for innovation and a need to preserve the existing system of production. Thus, although the literature insists on the necessity of the current change toward Industry 4.0, how to implement it remains problematic because the preservation of the factory is at stake. Moreover, the question of the evolution of the system depends on its innovative capability, but it is difficult to understand how a new rule can be designed and implemented in a factory. This tension between preservation and innovation is often explained in the literature as a process of creative destruction. Looking at the problem from another perspective, this article models the factory as a site of creative heritage, enabling creation within tradition, i.e., creating new rules while preserving the system of rules. Two case studies are presented to illustrate the model. The paper shows that design in the factory relies on the ability to validate solutions. To do so, the design process can explore and give new meaning to the existing rules. The role of innovation management is to choose the degree of revision of the rules and to make it possible.


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