Asymmetric Accumulation Research Articles

Electronic structure of thin films of hydrocarbon molecules under an external electric field

Using the density functional theory combined with the effective screening medium method, we studied the electronic structures of thin films of naphthalene under the external electric field in terms of their molecular conformation with respect to the electrode. Our calculations showed that the carrier accumulations and depletions strongly depend on the molecular conformation to the electrode. Carriers are primarily distributed on the molecules situated near the electrode. Furthermore, asymmetric carrier accumulation with respect to the carrier species occurs for the thin films where the molecules have tilting arrangements to the electrode. For the slabs consisting of six molecular layers, injected carriers are distributed throughout the slab irrespective of the carrier species. On the other hand, the carrier penetration is highly suppressed for the slabs where the molecules possess tilting conformation with respect to the electrode.

Developmental polarity shapes thermo-induced nastic movements in plants

ABSTRACTDirectional and non-directional environmental cues are able to induce polar behaviors of plants, which are termed tropic and nastic movements, respectively. While molecular mechanisms underlying the directionality of tropic movements are relatively well studied, it is poorly understood how the polarity of nastic movements is determined in response to non-directional stimuli, such as ambient temperatures. It has recently been shown that thermal induction of leaf hyponasty is stimulated by developmentally programmed polar auxin transport in Arabidopsis. Under warm environments, the PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) transcription factor binds to the promoter of PINOID (PID) gene, whose gene product modulates the polar trafficking of the auxin transporter PIN-FORMED 3 (PIN3). Notably, PIF4 binding to the PID promoter occurs predominantly in the abaxial petiole cells than the adaxial petiole cells, leading to differential PID expression and thus asymmetric auxin accumulation in the petiole cells. In addition, ASYMMETRIC LEAVES 1 (AS1), the well-characterized leaf polarity-determining epigenetic regulator, promotes the PID expression by modulating the patterns of histone 4 acetylation (H4Ac) in the PID chromatin. These observations demonstrate that developmental programming of the thermonastic leaf movement through polar auxin distribution enables plants to bend their leaves upward in response to non-directional thermal stimuli, contributing to cooling plant body temperatures under warm temperature conditions. We propose that a developmentally predetermined polarity plays a major role in governing the directionality of various nastic movements in plants.

Cytokinin inhibits cotton fiber initiation by disrupting PIN3a-mediated asymmetric accumulation of auxin in the ovule epidermis.

Auxin-dependent cell expansion is crucial for initiation of fiber cells in cotton (Gossypium hirsutum), which ultimately determines fiber yield and quality. However, the regulation of this process is far from being well understood. In this study, we demonstrate an antagonistic effect between cytokinin (CK) and auxin on cotton fiber initiation. In vitro and in planta experiments indicate that enhanced CK levels can reduce auxin accumulation in the ovule integument, which may account for the defects in the fiberless mutant xu142fl. In turn, supplementation with auxin can recover fiber growth of CK-treated ovules and mutant ovules. We further found that GhPIN3a is a key auxin transporter for fiber-cell initiation and is polarly localized to the plasma membranes of non-fiber cells, but not to those of fiber cells. This polar localization allows auxin to be transported within the ovule integument while specifically accumulating in fiber cells. We show that CKs antagonize the promotive effect of auxin on fiber cell initiation by undermining asymmetric accumulation of auxin in the ovule epidermis through down-regulation of GhPIN3a and disturbance of the polar localization of the protein.

Spatial Non-Uniform Hot Carrier Luminescence From 4H-SiC p-i-n Avalanche Photodiodes

4H-SiC avalanche photodiodes (APDs) working in Geiger mode are promising devices for ultra-weak ultraviolet light detection. In this letter, the degree of avalanche uniformity across device mesa of 4H-SiC p-i-n APDs is studied by imaging hot carrier luminescence pattern of the devices in avalanche regime. It is found that the luminescence emission from the APD under avalanche always first appears in the [ $\overline 1 \overline 1 20$ ] side of the top contact electrode. As over-bias increases, the luminescence pattern gradually extends toward the [ $11\overline 2 0$ ] direction and finally covers the whole device mesa. A physical model is proposed to explain the non-uniform avalanche phenomenon, in which the substrate off-orientation related carrier lateral drift would cause asymmetric hole accumulation and screening of junction electrical field along the [ $11\overline 2 0$ ] direction.

Reduced asymmetric dimethylarginine accumulation through inhibition of the type I protein arginine methyltransferases promotes renal fibrosis in obstructed kidneys.

The role of asymmetric dimethylarginine (ADMA) in chronic kidney disease (CKD) is unclear. Through inhibition of type I protein arginine methyltransferases (PRMTs), a novel strategy, we aimed to determine the effect of ADMA on renal fibrosis and explore its underlying working mechanisms. After sham or unilateral ureter ligation (UUO) operation, 20-25 g male c57 mice were treated with vehicle or PT1001B, an inhibitor of type I PRMTs, for 13 d. Moreover, human kidney 2 (HK2) and normal rat kidney 49F (NRK-49F) cells were treated with various concentrations of PT1001B or ADMA in the presence of 2.5 ng/ml TGF-β. We found that treatment with PT1001B increased the deposition of extracellular matrix proteins, the expression of α smooth muscle actin, and connective tissue growth factor in UUO-induced fibrotic kidneys, which is correlated with reduced expression of PRMT1, reduced the production of ADMA, and increased expression of uromodulin. In TGF-β-stimulated HK2 and NRK-49F cells, PT1001B dose-dependently inhibited ADMA production, increased NO concentrations, and enhanced the expression of profibrotic proteins. Exogenous addition of ADMA inhibited the expression of profibrotic proteins dose-dependently and attenuated the profibrotic effect of PT1001B. Moreover, ADMA reduced the NO concentration in PT1001B-treated HK2 cells. Finally, we conclude that ADMA has an antifibrotic effect in obstructed kidneys, and future application of type I PRMT inhibitor should be done cautiously for patients with CKD.-Wu, M., Lin, P., Li, L., Chen, D., Yang, X., Xu, L., Zhou, B., Wang, C., Zhang, Y., Luo, C., Ye, C. Reduced asymmetric dimethylarginine accumulation through inhibition of the type I protein arginine methyltransferases promotes renal fibrosis in obstructed kidneys.

The IMF As a Biased Global Insurance Mechanism: Asymmetrical Moral Hazard, Reserve Accumulation, and Financial Crises

The IMF As a Biased Global Insurance Mechanism: Asymmetrical Moral Hazard, Reserve Accumulation, and Financial Crises

Multi-parameter stochastic inversion for first and second moment mass properties of a model-scale ship with topside ice accumulation

This work investigates the indirect monitoring of ice accretion on ship surfaces using a stochastic inversion framework. An accurate assessment of a ship's mass properties during operation is an important concern for ships traveling within the Arctic, where ice accumulation is a concern. Within such contexts, the actual (i.e., current) first and second moment properties of the vessel, including accumulated topside icing, must be considered within the associated equations of motion for a given ship. By leveraging instrumentation such as an existing on-board inertial measurement unit (IMU), in conjunction with existing seakeeping software, the proposed framework recovers a statistical description of two mass properties, simultaneously. The subsequent stochastic inverse problem is solved using the proposed framework in arriving at two mass properties in particular: the vertical center of gravity (a first moment mass property) and the roll gyradius (a second moment mass property).The inversion scheme requires two main inputs: an observed ground truth for the roll period, and an associated signal-to-noise ratio for the roll period measurement. The framework applies a Markov chain Monte Carlo (MCMC) inversion scheme, implemented in Python, that leverages the Standard Ship Motion Program (SMP95) software in order to build a posterior distribution for the desired mass properties. Experimental model results for Research Vessel (R/V) Melville are used to validate the proposed framework. Six different configurations, including one case of no icing and five cases of topside icing, are investigated within the context of this framework in order to invert for their respective roll gyradii and vertical centers of gravity. Icing configurations include both asymmetric and symmetric ice accumulation under moderate to heavy icing conditions. Recommendations concerning strategies for applying the proposed framework are offered.

Citrus tristeza virus co-opts glyceraldehyde 3-phosphate dehydrogenase for its infectious cycle by interacting with the viral-encoded protein p23.

Key messageCitrus tristeza virus encodes a unique protein, p23, with multiple functional roles that include co-option of the cytoplasmic glyceraldehyde 3-phosphate dehydrogenase to facilitate the viral infectious cycle.The genome of citrus tristeza virus (CTV), genus Closterovirus family Closteroviridae, is a single-stranded (+) RNA potentially encoding at least 17 proteins. One (p23), an RNA-binding protein of 209 amino acids with a putative Zn-finger and some basic motifs, displays singular features: (i) it has no homologues in other closteroviruses, (ii) it accumulates mainly in the nucleolus and Cajal bodies, and in plasmodesmata, and (iii) it mediates asymmetric accumulation of CTV RNA strands, intracellular suppression of RNA silencing, induction of some CTV syndromes and enhancement of systemic infection when expressed as a transgene ectopically or in phloem-associated cells in several Citrus spp. Here, a yeast two-hybrid screening of an expression library of Nicotiana benthamiana (a symptomatic experimental host for CTV), identified a transducin/WD40 domain protein and the cytosolic glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as potential host interactors with p23. Bimolecular fluorescence complementation corroborated the p23-GAPDH interaction in planta and showed that p23 interacts with itself in the nucleolus, Cajal bodies and plasmodesmata, and with GAPDH in the cytoplasm (forming aggregates) and in plasmodesmata. The latter interaction was preserved in a p23 deletion mutant affecting the C-terminal domain, but not in two others affecting the Zn-finger and one internal basic motif. Virus-induced gene silencing of GAPDH mRNA resulted in a decrease of CTV titer as revealed by real-time RT-quantitative PCR and RNA gel-blot hybridization. Thus, like other viruses, CTV seems to co-opt GAPDH, via interaction with p23, to facilitate its infectious cycle.

Control of Growth Cone Polarity, Microtubule Accumulation, and Protrusion by UNC-6/Netrin and Its Receptors in Caenorhabditis elegans.

UNC-6/Netrin has a conserved role in dorsal-ventral axon guidance, but the cellular events in the growth cone regulated by UNC-6/Netrin signaling during outgrowth are incompletely understood. Previous studies showed that, in growth cones migrating away from UNC-6/Netrin, the receptor UNC-5 regulates growth cone polarity, as observed by polarized F-actin, and limits the extent of growth cone protrusion. It is unclear how UNC-5 inhibits protrusion, and how UNC-40 acts in concert with UNC-5 to regulate polarity and protrusion. New results reported here indicate that UNC-5 normally restricts microtubule (MT) + end accumulation in the growth cone. Tubulin mutant analysis and colchicine treatment suggest that stable MTs are necessary for robust growth cone protrusion. Thus, UNC-5 might inhibit protrusion in part by restricting growth cone MT accumulation. Previous studies showed that the UNC-73/Trio Rac GEF and UNC-33/CRMP act downstream of UNC-5 in protrusion. Here, we show that UNC-33/CRMP regulates both growth cone dorsal asymmetric F-actin accumulation and MT accumulation, whereas UNC-73/Trio Rac GEF activity only affects F-actin accumulation. This suggests an MT-independent mechanism used by UNC-5 to inhibit protrusion, possibly by regulating lamellipodial and filopodial actin. Furthermore, we show that UNC-6/Netrin and the receptor UNC-40/DCC are required for excess protrusion in unc-5 mutants, but not for loss of F-actin asymmetry or MT + end accumulation, indicating that UNC-6/Netrin and UNC-40/DCC are required for protrusion downstream of, or in parallel to, F-actin asymmetry and MT + end entry. F-actin accumulation might represent a polarity mark in the growth cone where protrusion will occur, and not protrusive lamellipodial and filopodial actin per se Our data suggest a model in which UNC-6/Netrin first polarizes the growth cone via UNC-5, and then regulates protrusion based upon this polarity (the polarity/protrusion model). UNC-6/Netrin inhibits protrusion ventrally via UNC-5, and stimulates protrusion dorsally via UNC-40, resulting in dorsally-directed migration. The polarity/protrusion model represents a novel conceptual paradigm in which to understand axon guidance and growth cone migration away from UNC-6/Netrin.

Rbpms2 functions in Balbiani body architecture and ovary fate.

The most prominent developmental regulators in oocytes are RNA-binding proteins (RNAbps) that assemble their targets into ribonucleoprotein granules where they are stored, transported and translationally regulated. RNA-binding protein of multiple splice forms 2, or Rbpms2, interacts with molecules that are essential to reproduction and egg patterning, including bucky ball, a key factor for Bb formation. Rbpms2 is localized to germ granules in primordial germ cells (PGCs) and to the Balbiani body (Bb) of oocytes, although the mechanisms regulating Rbpms2 localization to these structures are unknown. Using mutant Rbpms2 proteins, we show that Rbpms2 requires distinct protein domains to localize within germ cells and somatic cells. Accumulation and localization to subcellular compartments in the germline requires an intact RNA binding domain. Whereas in zebrafish somatic blastula cells, the conserved C-terminal domain promotes localization to the bipolar centrosomes/spindle. To investigate Rbpms2 functions, we mutated the duplicated and functionally redundant zebrafish rbpms2 genes. The gonads of rbpms2a;2b (rbpms2) mutants initially contain early oocytes, however definitive oogenesis ultimately fails during sexual differentiation and, rbpms2 mutants develop as fertile males. Unlike other genes that promote oogenesis, failure to maintain oocytes in rbpms2 mutants was not suppressed by mutation of Tp53. These findings reveal a novel and essential role for rbpms2 in oogenesis. Ultrastructural and immunohistochemical analyses revealed that rbpms2 is not required for the asymmetric accumulation of mitochondria and Buc protein in oocytes, however its absence resulted in formation of abnormal Buc aggregates and atypical electron-dense cytoplasmic inclusions. Our findings reveal novel and essential roles for rbpms2 in Buc organization and oocyte differentiation.

Bacterial EndoMS/NucS acts as a clamp-mediated mismatch endonuclease to prevent asymmetric accumulation of replication errors.

Mismatch repair (MMR) systems based on MutS eliminate mismatches originating from replication errors. Despite extensive conservation of mutS homologues throughout the three domains of life, Actinobacteria and some archaea do not have genes homologous to mutS. Here, we report that EndoMS/NucS of Corynebacterium glutamicum is the mismatch-specific endonuclease that functions cooperatively with a sliding clamp. EndoMS/NucS function in MMR was fully dependent on physical interaction between EndoMS/NucS and sliding clamp. A combination of endoMS/nucS gene disruption and a mutation in dnaE, which reduced the fidelity of DNA polymerase, increased the mutation rate synergistically and confirmed the participation of EndoMS in replication error correction. EndoMS specifically cleaved G/T, G/G and T/T mismatches in vitro, and such substrate specificity was consistent with the mutation spectrum observed in genome-wide analyses. The observed substrate specificity of EndoMS, together with the effects of endoMS gene disruption, led us to speculate that the MMR system, regardless of the types of proteins in the system, evolved to address asymmetrically occurring replication errors in which G/T mismatches occur much more frequently than C/A mismatches.

UV-B Radiation Induces Root Bending Through the Flavonoid-Mediated Auxin Pathway in Arabidopsis.

Ultraviolet (UV)-B radiation-induced root bending has been reported; however, the underlying mechanisms largely remain unclear. Here, we investigate whether and how auxin and flavonoids are involved in UV-B radiation-induced root bending in Arabidopsis using physiological, pharmacological, and genetic approaches. UV-B radiation modulated the direction of root growth by decreasing IAA biosynthesis and affecting auxin distribution in the root tips, where reduced auxin accumulation and asymmetric auxin distribution were observed. UV-B radiation increased the distribution of auxin on the nonradiated side of the root tips, promoting growth and causing root bending. Further analysis indicated that UV-B induced an asymmetric accumulation of flavonoids; this pathway is involved in modulating the accumulation and asymmetric distribution of auxin in root tips and the subsequent redirection of root growth by altering the distribution of auxin carriers in response to UV-B radiation. Taken together, our results indicate that UV-B radiation-induced root bending occurred through a flavonoid-mediated phototropic response to UV-B radiation.

The Catumbela delta (SW Angola). Processes determining a history of changing asymmetry

It is presented an investigation on the morpho-sedimentary evolution of one of the largest sub-aerial delta protrusions in west Africa: the Catumbela delta. The planform geometry of this delta is characteristic of an asymmetric wave-dominated accumulation, strongly influenced by a north-directed longshore drift. Its post-glacial Holocene construction passed through morphological transformations linked with the relocation of the main fluvial channels and river mouths. Avulsion processes in the delta plain are responsible for an alternation between two major channel courses: one directed E-W and broadly coincident with today’s path and the other placed to the north with a SSE-NNW direction. Delta growth started during a period of deceleration of sea-level rise and high rainfall (c.a. 7 ka BP) and was enhanced after the 4.5 ka. BP sea-level highstand. A deflected delta configuration was promoted by the c.a. 2–3 ka BP climatic crisis, when fluvial sediment supply was reduced and sediment bypassing limited to a minimum, forcing the channel to run parallel to the coastline. This configuration can be regarded as one of the finest worldwide examples of medium-size deflected deltas. The later updrift migration in the position of the river mouth was probably determined by an increase in fluvial supply driven by an upsurge in the seasonal rainfall in the drainage area and, in particular during the last 200 years of Portuguese occupation of the territory, changes in land-use. The updrift migration, however, was irregular, being punctuated by events of downdrift shifts and two channel courses with outlets several km apart may persist during wet periods.

Distribution of Endogenous NO Regulates Early Gravitropic Response and PIN2 Localization in Arabidopsis Roots.

High-resolution and automated image analysis of individual roots demonstrated that endogenous nitric oxide (NO) contribute significantly to gravitropism of Arabidopsis roots. Lowering of endogenous NO concentrations strongly reduced and even reversed gravitropism, resulting in upward bending, without affecting root growth rate. Notably, the asymmetric accumulation of NO along the upper and lower sides of roots correlated with a positive gravitropic response. Detection of NO by the specific DAF-FM DA fluorescent probe revealed that NO was higher at the lower side of horizontally-oriented roots returning to initial values 2 h after the onset of gravistimulation. We demonstrate that NO promotes plasma membrane re-localization of PIN2 in epidermal cells, which is required during the early root gravitropic response. The dynamic and asymmetric localization of both auxin and NO is critical to regulate auxin polar transport during gravitropism. Our results collectively suggest that, although auxin and NO crosstalk occurs at different levels of regulation, they converge in the regulation of PIN2 membrane trafficking in gravistimulated roots, supporting the notion that a temporally and spatially coordinated network of signal molecules could participate in the early phases of auxin polar transport during gravitropism.

Regulation of asymmetric polar auxin transport by PsPIN1 in endodermal tissues of etiolated Pisum sativum epicotyls: focus on immunohistochemical analyses.

This manuscript reportsthe production of specific polyclonal antibodies for PsPIN1, a putative auxin efflux carrier in Alaska pea (Pisum sativum L.) plants, and the cellular immunolocalization of PsPIN1. When pea seeds were set with the seed axis horizontal to the upper surface of a rockwool block, and allowed to germinate and grow for 3days in the dark, the epicotyl grew upward. On the other hand, the application of 2,3,5-triiodobenzoic acid (TIBA) inhibited graviresponse. In the subapical epicotyl regions, PsPIN1 has been found to localize in the basal side of the plasma membrane of cells in endodermal tissues. Asymmetric PsPIN1 localization between the proximal and distal sides of the epicotyl was observed, the total amounts of PsPIN1 being more abundant in the proximal side. The asymmetric PsPIN1 distribution between the proximal and distal sides of the epicotyl was well correlated with unequal polar auxin transport as well as asymmetric accumulation of mRNA of PsPIN1 (Ueda et al. in Biol Sci Space 26:32-41, 2012; Ueda et al. in Plant Biol 16(suppl 1):43-49, 2014). In the proximal side of an apical hook, PsPIN1 localized in the basal side of the plasma membrane of cells in endodermal tissues, whereas in the distal side, the abundant distribution of PsPIN1 localized in the basal-lower (endodermal) side of the basal plasma membrane, suggesting possible lateral auxin movement from the distal side to the proximal side in this region. The application of TIBA significantly reduced the amount of PsPIN1 in the proximal side of epicotyls, but little in the distal side. These results suggest that unequal auxin transport in epicotyls during the early growth stage of etiolated pea seedlings is derived from asymmetric PsPIN1 localization in the apical hook and subapical region of epicotyls, and that asymmetric transport between the proximal and distal sides of epicotyls is required for the graviresponse of epicotyls.

CLAMP/Spef1 regulates planar cell polarity signaling and asymmetric microtubule accumulation in the Xenopus ciliated epithelia.

Most epithelial cells polarize along the axis of the tissue, a feature known as planar cell polarity (PCP). The initiation of PCP requires cell-cell signaling via the noncanonical Wnt/PCP pathway. Additionally, changes in the cytoskeleton both facilitate and reflect this polarity. We have identified CLAMP/Spef1 as a novel regulator of PCP signaling. In addition to decorating microtubules (MTs) and the ciliary rootlet, a pool of CLAMP localizes at the apical cell cortex. Depletion of CLAMP leads to the loss of PCP protein asymmetry, defects in cilia polarity, and defects in the angle of cell division. Additionally, depletion of CLAMP leads to a loss of the atypical cadherin-like molecule Celrs2, suggesting that CLAMP facilitates the stabilization of junctional interactions responsible for proper PCP protein localization. Depletion of CLAMP also affects the polarized organization of MTs. We hypothesize that CLAMP facilitates the establishment of cell polarity and promotes the asymmetric accumulation of MTs downstream of the establishment of proper PCP.

Social Injustice in Surveillance Capitalism

A rapidly accelerating phase of capitalism based on asymmetrical personal data accumulation poses significant concerns for democratic societies, yet the concepts used to understand and challenge practices of dataveillance are insufficient or poorly elaborated. Against a backdrop of growing corporate power enabled by legal lethargy and the secrecy of the personal data industry, this paper makes explicit how the practices inherent to what Shoshana Zuboff calls ‘surveillance capitalism’ are threats to social justice, based on the normative principle that they prevent parity of participation in social life. This paper draws on Nancy Fraser’s theory of ‘abnormal justice’ to characterize the separation of people from their personal data and its accumulation by corporations as an economic injustice of maldistribution. This initial injustice is also the key mechanism by which further opaque but significant forms of injustice are enabled in surveillance capitalism—sociocultural misrecognition which occurs when personal data are algorithmically processed and subject to categorization, and political misrepresentation which renders people democratically voiceless, unable to challenge misuses of their data. In situating corporate dataveillance practices as a threat to social justice, this paper calls for more explicit conceptual development of the social harms of asymmetrical personal data accumulation and analytics, and more hopefully, attention to the requirements needed to recast personal data as an agent of equality rather than oppression.

Elucidating the major hidden genomic components of the A, C, and AC genomes and their influence on Brassica evolution

Decoding complete genome sequences is prerequisite for comprehensive genomics studies. However, the currently available reference genome sequences of Brassica rapa (A genome), B. oleracea (C) and B. napus (AC) cover 391, 540, and 850 Mbp and represent 80.6, 85.7, and 75.2% of the estimated genome size, respectively, while remained are hidden or unassembled due to highly repetitive nature of these genome components. Here, we performed the first comprehensive genome-wide analysis using low-coverage whole-genome sequences to explore the hidden genome components based on characterization of major repeat families in the B. rapa and B. oleracea genomes. Our analysis revealed 10 major repeats (MRs) including a new family comprising about 18.8, 10.8, and 11.5% of the A, C and AC genomes, respectively. Nevertheless, these 10 MRs represented less than 0.7% of each assembled reference genome. Genomic survey and molecular cytogenetic analyses validates our insilico analysis and also pointed to diversity, differential distribution, and evolutionary dynamics in the three Brassica species. Overall, our work elucidates hidden portions of three Brassica genomes, thus providing a resource for understanding the complete genome structures. Furthermore, we observed that asymmetrical accumulation of the major repeats might be a cause of diversification between the A and C genomes.

Do weak global stresses synchronize earthquakes?

AbstractInsofar as slip in an earthquake is related to the strain accumulated near a fault since a previous earthquake, and this process repeats many times, the earthquake cycle approximates an autonomous oscillator. Its asymmetric slow accumulation of strain and rapid release is quite unlike the harmonic motion of a pendulum and need not be time predictable, but still resembles a class of repeating systems known as integrate‐and‐fire oscillators, whose behavior has been shown to demonstrate a remarkable ability to synchronize to either external or self‐organized forcing. Given sufficient time and even very weak physical coupling, the phases of sets of such oscillators, with similar though not necessarily identical period, approach each other. Topological and time series analyses presented here demonstrate that earthquakes worldwide show evidence of such synchronization. Though numerous studies demonstrate that the composite temporal distribution of major earthquakes in the instrumental record is indistinguishable from random, the additional consideration of event renewal interval serves to identify earthquake groupings suggestive of synchronization that are absent in synthetic catalogs. We envisage the weak forces responsible for clustering originate from lithospheric strain induced by seismicity itself, by finite strains over teleseismic distances, or by other sources of lithospheric loading such as Earth's variable rotation. For example, quasi‐periodic maxima in rotational deceleration are accompanied by increased global seismicity at multidecadal intervals.

Asymmetric carrier accumulation in double-walled carbon nanotube by an external electric field

We studied the electronic structure of a double-walled carbon nanotube (DWCNT) in a field-effect transistor structure under an external electric field. Our calculations using density functional theory combined with the effective screening medium method showed that the carrier accumulation in the DWCNT is sensitive to the carrier species and concentration. Injected holes are distributed primarily on the outer wall of the DWCNT, whereas the electrons are accommodated on both its outer and inner walls. The extended nature of the accumulated electron density leads to an interwall electric field from the outer to the inner wall.