494 research outputs found

    Monitoring Newly Adopted Technologies Using Keyword Based Analysis of Cited Patents

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    This paper proposes a method that can reliably monitor the adoption of existing technology by term frequency-inverse document frequency (11-IDF) and K-means clustering using cited patents. 11-IDF and K-means clustering can extract patent information when the number of patents is sufficiently large. When the number of patents is too small for 11-IDF and K-means clustering to be reliable, the method considers patents that were cited by the originally set of patents. The mixed set of citing patents and cited patents is the new subject of analysis. As a case study, we have focused in agricultural tractor in which new technologies were adopted to achieve automated driving. TF-IDF and K-means clustering alone failed to monitor the adoption of new technology but the proposed method successfully monitored it. We anticipate that our method can ensure the reliability of patent monitoring even when the number of patents is small.11Ysciescopu

    Typhoon‐induced, highly nonlinear internal solitary waves off the east coast of Korea

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94585/1/grl22467.pd

    Surface warming slowdown with continued subsurface warming in the East Sea (Japan Sea) over recent decades (2000–2014)

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    The long-term surface warming trend in the East Sea (Japan Sea; ES hereafter) stalled from 2000 to 2014 (−0.05°C yr−1, surface warming slowdown), while the subsurface (100–300°m) warming trend continued (+0.03°C yr−1). To address the processes underlying these contrasting trends in surface and subsurface temperature change, the trends in sea-level anomaly, isopycnal depth, and wind pattern were analyzed using monthly mean ocean reanalysis system 4 (ORAS4) data. During this period, the strengthened northwesterly/northerly wind in the central part of ES is supposed to contribute to a negative (positive) wind stress curl to its west (east), corresponding to an anticyclonic (cyclonic) circulation in the west (east). Furthermore, the induced negative wind stress in the west appears to enhance the northward penetration of East Korean Warm Current (EKWC), the slowdown in its eastward meandering around 38° N from the Korea coast, resulting in warm water accumulation in the west with peak warm anomaly at relatively greater depth compared to peak cold anomaly in the east. Overall, these wind-driven changes in transport from west to east, wind stress curl induced horizontal divergence (convergence) and the associated upwelling (downwelling), causes surface warming to slow and subsurface warming to persist during 2000 to 2014

    An auxin-mediated ultradian rhythm positively influences root regeneration via EAR1/EUR1 in Arabidopsis

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    Ultradian rhythms have been proved to be critical for diverse biological processes. However, comprehensive understanding of the short-period rhythms remains limited. Here, we discover that leaf excision triggers a gene expression rhythm with ~3-h periodicity, named as the excision ultradian rhythm (UR), which is regulated by the plant hormone auxin. Promoter–luciferase analyses showed that the spatiotemporal patterns of the excision UR were positively associated with de novo root regeneration (DNRR), a post-embryonic developmental process. Transcriptomic analysis indicated more than 4,000 genes including DNRR-associated genes were reprogramed toward ultradian oscillation. Genetic studies showed that EXCISION ULTRADIAN RHYTHM 1 (EUR1) encoding ENHANCER OF ABSCISIC ACID CO-RECEPTOR1 (EAR1), an abscisic acid signaling regulator, was required to generate the excision ultradian rhythm and enhance root regeneration. The eur1 mutant exhibited the absence of auxin-induced excision UR generation and partial failure during rescuing root regeneration. Our results demonstrate a link between the excision UR and adventitious root formation via EAR1/EUR1, implying an additional regulatory layer in plant regeneration

    Optical Mobius symmetry in metamaterials

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    We experimentally observed a new topological symmetry in optical composites, namely, metamaterials. While it is not found yet in nature materials, the electromagnetic Mo¨bius symmetry discovered in metamaterials is equivalent to the structural symmetry of a Mo¨bius strip, with the number of twists controlled by the sign change of the electromagnetic coupling between the meta-atoms. We further demonstrate that metamaterials with different coupling signs exhibit resonance frequencies that depend only on the number but not the locations of the ‘‘twists,’’ thus confirming its topological nature. The new topological symmetry found in metamaterials may enable unique functionalities in optical materialsThis work was supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 on simulations and fabrication, and by the NSF Nano-scale Science and Engineering Center (NSEC) under Grant No. CMMI-0751621 for optical characterizations

    Observational needs for improving ocean and coupled reanalysis, S2S prediction, and decadal prediction

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    Developments in observing system technologies and ocean data assimilation (DA) are symbiotic. New observation types lead to new DA methods and new DA methods, such as coupled DA, can change the value of existing observations or indicate where new observations can have greater utility for monitoring and prediction. Practitioners of DA are encouraged to make better use of observations that are already available, for example, taking advantage of strongly coupled DA so that ocean observations can be used to improve atmospheric analyses and vice versa. Ocean reanalyses are useful for the analysis of climate as well as the initialization of operational long-range prediction models. There are many remaining challenges for ocean reanalyses due to biases and abrupt changes in the ocean-observing system throughout its history, the presence of biases and drifts in models, and the simplifying assumptions made in DA solution methods. From a governance point of view, more support is needed to bring the ocean-observing and DA communities together. For prediction applications, there is wide agreement that protocols are needed for rapid communication of ocean-observing data on numerical weather prediction (NWP) timescales. There is potential for new observation types to enhance the observing system by supporting prediction on multiple timescales, ranging from the typical timescale of NWP, covering hours to weeks, out to multiple decades. Better communication between DA and observation communities is encouraged in order to allow operational prediction centers the ability to provide guidance for the design of a sustained and adaptive observing network

    Ice front retreat reconfigures meltwater-driven gyres modulating ocean heat delivery to an Antarctic ice shelf

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    Pine Island Ice Shelf (PIIS) buttresses the Pine Island Glacier, the key contributor to sea-level rise. PIIS has thinned owing to ocean-driven melting, and its calving front has retreated, leading to buttressing loss. PIIS melting depends primarily on the thermocline variability in its front. Furthermore, local ocean circulation shifts adjust heat transport within Pine Island Bay (PIB), yet oceanic processes underlying the ice front retreat remain unclear. Here, we report a PIB double-gyre that moves with the PIIS calving front and hypothesise that it controls ocean heat input towards PIIS. Glacial melt generates cyclonic and anticyclonic gyres near and off PIIS, and meltwater outflows converge into the anticyclonic gyre with a deep-convex-downward thermocline. The double-gyre migrated eastward as the calving front retreated, placing the anticyclonic gyre over a shallow seafloor ridge, reducing the ocean heat input towards PIIS. Reconfigurations of meltwater-driven gyres associated with moving ice boundaries might be crucial in modulating ocean heat delivery to glacial ice
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