Peak effect at the weak- to strong pinning crossover

In type-II superconductors, the magnetic field enters in the form of vortices; their flow under application of a current introduces dissipation and thus destroys the defining property of a superconductor. Vortices get immobilized by pinning through material defects, thus resurrecting the supercurrent. In weak collective pinning, defects compete and only fluctuations in the defect density produce pinning. On the contrary, strong pins deform the lattice and induce metastabilities. Here, we focus on the crossover from weak- to strong bulk pinning, which is triggered either by increasing the strength $f_\mathrm{p}$ of the defect potential or by decreasing the effective elasticity of the lattice (which is parametrized by the Labusch force $f_\mathrm{Lab}$). With an appropriate Landau expansion of the free energy we obtain a peak effect with a sharp rise in the critical current density $j_\mathrm{c} \sim j_0 (a_0\xi^2 n_p) (\xi^2/a_0^2) (f_\mathrm{p}/f_\mathrm{Lab} -1)^2$.Comment: 6 pages, 5 figures (Proceedings of the Third European Conference on Vortex Matter in Superconductors, to be published in Physica C

ENTERPRISE ARCHITECTURE AS A MEANS FOR COORDINATION – AN EMPIRICAL STUDY ON ACTUAL AND POTENTIAL PRACTICE

Enterprise architecture management (EAM) is considered a means to guide the alignment of business- and IT-related concerns from an enterprise-wide perspective. Our goal in this paper is to understand by which means EAM supports this coordination task today and potentially in the future. We designed a questionnaire and conducted an empirical study (n=95) with participants from the field of EAM. Based on common coordination mechanisms from literature, we analyze (1) the relation between coordination mechanism and their current EAM support, (2) to what degree participants are aware of opportunities of EAM supporting coordination mechanisms, and (3) what the perceived gap between potential and realized EAM coordination support is. An exploratory factor analysis leads to three factors that represent coordination mechanisms in enterprises. Using these factors, we group participating enterprises in three different clusters: (1) non-coordinators, (2) dominators and (3) negotiators. We find that a similar awareness of opportunities exists in all three clusters, yet there are gaps in the realization of EAM coordination support: non-coordinators show the lowest realization, negotiators the highest. Based on this clustering, we provide implications on further EAM development options

Understanding Coordination Support of Enterprise Architecture Management – Empirical Analysis and Implications for Practice

Enterprise architecture management (EAM) is a means to guide the consistent evolution of business and IT artifacts from an enterprise-wide perspective. This paper aims at understanding the means by which EAM supports this coordination task. Informed by theory of coordination and based on empirical data (n=95) we group participating enterprises in different clusters: (1) non-coordinators, (2) dominators and (3) negotiators. We find that a similar awareness of opportunities exists in all three clusters, yet there are gaps in the realization of EAM coordination support: non-coordinators show the lowest realization, negotiators the highest. Based on this clustering and two follow-up focus groups, we provide implications about the occurrence of the clusters in enterprises and on further EAM development options

Patatin-related phospholipases (pPLA) and other cytosolic components in auxin binding protein1 (ABP1)-mediated auxin signaling are revealed by using early auxin-induced gene expression as a biotest in Arabidopsis thaliana

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Phospholipases and the Network of Auxin Signal Transduction with ABP1 and TIR1 as Two Receptors: A Comprehensive and Provocative Model

Three types of phospholipases, phospholipase D, secreted phospholipase A2, and patatin-related phospholipase A (pPLA) have functions in auxin signal transduction. Potential linkage to auxin receptors ABP1 or TIR1, their rapid activation or post-translational activation mechanisms, and downstream functions regulated by these phospholipases is reviewed and discussed. Only for pPLA all aspects are known at least to some detail. Evidence is gathered that all these signal reactions are located in the cytosol and seem to merge on regulation of PIN-catalyzed auxin efflux transport proteins. As a consequence, auxin concentration in the nucleus is also affected and this regulates the E3 activity of this auxin receptor. We showed that ABP1, PIN2, and pPLA, all outside the nucleus, have an impact on regulation of auxin-induced genes within 30 min. We propose that regulation of PIN protein activities and of auxin efflux transport are the means to coordinate ABP1 and TIR1 activity and that no physical contact between components of the ABP1-triggered cytosolic pathways and TIR1-triggered nuclear pathways of signaling is necessary to perform this

Linear Trend Analysis: Implications for a Structural Fracture System and Applications of Subsurface Fluid Migration, Northwest Arkansas and Eastern Oklahoma

Lineaments are mappable, simple or composite linear or curvilinear features of the Earth’s surface longer than one mile, which differ from the patterns of adjacent features and are presumed to reflect subsurface phenomenon such as faults and fractures. The usage of the term refers to the description Lattman published in 1958 and was the foundation for work by MacDonald in 1977, which is the basis for this project. Remote sensing techniques have provided a valuable means to analyze lineaments on a large scale in a relatively short time in comparison to field mapping methods. The products of such fracture studies have been used in exploration for groundwater and may also have implications for other subsurface fluid migration pathways. Cost-benefit evaluations of employing remote sensing techniques have found that this method took less time and saved on costs of drilling. Published work completed by MacDonald included a compilation of lineament maps for 13 counties in Northwest Arkansas. The maps were published on county highway basemaps and prepared using LANDSAT imagery that was later transferred. Quality of remotely sensed imagery has increased exponentially since the time of the original production and in 2006 the map was digitized by a group of NSF Research Experience for Undergraduate students. Comparison of the digital lineament data to more modern imagery allowed a check on accuracy and extension or modification where appropriate. The final products include a compilation of all relevant literature and data sources related to water quality investigations in mantled karst and fractured rock areas of Arkansas including the Ozark Dome area and Arkoma basin to the western border and east to the Fall Line. As well as digitization of a lineament map containing the 27 counties based on the most current Digital Elevation Models (DEMs) and satellite imagery available

Transcription of TIR1-Controlled Genes Can be Regulated within 10 Min by an Auxin-Induced Process. Can TIR1 be the Receptor?

ABP1 and TIR1/AFBs are known as auxin receptors. ABP1 is linked to auxin responses several of which are faster than 10 min. TIR1 regulates auxin-induced transcription of early auxin genes also within minutes. We use transcription of such TIR1-dependent genes as indicator of TIR1 activity to show the rapid regulation of TIR1 by exogenous auxin. To this end, we used quantification of transcription of a set of fifteen early auxin-induced reporter genes at t = 10 and t = 30 min to measure this as a TIR1-dependent auxin response. We conducted this study in 22 mutants of auxin transporters (pin5, abcb1, abcb19, and aux1/lax3), protein kinases and phosphatases (ibr5, npr1, cpk3, CPK3-OX, d6pk1, d6pkl1-1, d6pkl3-2, d6pkl1-1/d6pkl2-2, and d6pkl1-1/d6pkl3-2), of fatty acid metabolism (fad2-1, fad6-1, ssi2, lacs4, lacs9, and lacs4/lacs9) and receptors (tir1, tir1/afb2, and tir1/afb3) and compared them to the wild type. After 10 min auxin application, in 18 out of 22 mutants mis-regulated expression of at least one reporter was found, and in 15 mutants transcription of two-to-three out of five selected auxin reporter genes was mis-regulated. After 30 min of auxin application to mutant plants, mis-regulation of reporter genes ranged from one to 13 out of 15 tested reporter genes. Those genes chosen as mutants were themselves not regulated in their expression by auxin for at least 1 h, excluding an influence of TIR1/AFBs on their transcription. The expression of TIR1/AFB genes was also not modulated by auxin for up to 3 h. Together, this excludes a feedback or feedforward of these mutant genes/proteins on TIR1/AFBs output of transcription in this auxin-induced response. However, an auxin-induced response needed an as yet unknown auxin receptor. We suggest that the auxin receptor necessary for the fast auxin-induced transcription modulation could be, instead, ABP1. The alternative hypothesis would be that auxin-induced expression of a protein, initiated by TIR1/AFBs receptors, could initiate these responses and that this unknown protein regulated TIR1/AFB activities within 10 min.DLR/50WB133DFG/Sche207/24-

Weak- to strong pinning crossover

Material defects in hard type II superconductors pin the flux lines and thus establish the dissipation-free current transport in the presence of a finite magnetic field. Depending on the density and pinning force of the defects and the vortex density, pinning is either weak-collective or strong. We analyze the weak- to strong pinning crossover of vortex matter in disordered superconductors and discuss the peak effect appearing naturally in this context.Comment: 4 pages, 2 figure

Complementation of the embryo-lethal T-DNA insertion mutant of AUXIN-BINDING-PROTEIN 1 (ABP1) with abp1 point mutated versions reveals crosstalk of ABP1 and phytochromes

AUXIN BINDING PROTEIN1 (ABP1) mutants have properties of auxin- and red light-signalling mutants. A novel concept for growth control by ABP1 and phytochromes is indicated by this functional lin