223 research outputs found

    Time-Resolved Electromagnetic Near-Field Scanning: Dual Sparse Sampling in Time and Space

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    Time-resolved electromagnetic near-field scanning plays a pivotal role in antenna measurement and unraveling complex electromagnetic interference and compatibility issues. However, the rapid acquisition of high-resolution spatio–temporal data remains challenging due to physical constraints, such as moving the probe position and allowing sufficient time for sampling. This article presents a novel hybrid approach combining kriging for sparse spatial measurement, compressed sensing (cs) for sparse temporal sampling, and dynamic mode decomposition (dmd) for comprehensive analysis of the dual-sparse sampling electromagnetic near-field data. We leverage cs to optimize sparse sampling in the time domain and latin hypercube sampling to guide the probe position and realize sparse measurement in the space domain. By leveraging the inherent sparsity within electromagnetic radiated signals, cs reliably represents time-domain signals while reducing the required time samples. Then, dmd is used to extract meaningful insights from the resulting sparse spatio–temporal data, resulting in the sparse dynamic modes and temporal evolution information. Next, the kriging is employed to infer missing spatial measurements for each sparse dynamic mode. Finally, the entire spatio–temporal signals are reconstructed based on interpolated dynamic modes and temporal evolution information. An example using crossed dipole antennas as the device under test is provided to validate the proposed method. It is found that the proposed kriging-cs-dmd framework effectively reconstructs electromagnetic fields with precision while simultaneously reducing the measurement workload in both the time and space domains. This methodology could be further employed for various applications, such as space–time-modulated electronic devices

    Comparing reading strategy measures and L2 readers’ performance on different comprehension tasks

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    In second language (L2) reading strategy research, two concerns need addressing: (1) the discrepancy in assessing strategy use between written surveys and verbal reports, and (2) the effect of using strategies on readers’ comprehension outcomes when different types of comprehension tasks are utilized. The present study addressed these concerns by asking five more-proficient and five less-proficient Chinese English as a foreign language (EFL) university learners to read two domain-specific texts while assessing their strategy use. The results from both quantitative and qualitative analyses revealed a “gap” between the survey and verbal reports for assessing L2 reading strategy use. Additionally, the contribution of strategies to the readers’ comprehension was found to vary by comprehension task type. Similarly, the variety of strategy use had a strong association with the readers’ performance on only one of three types of comprehension tasks, free recall. The findings hold important implications on L2 reading strategy instruction

    In vitro propagation of katsura tree (Cercidiphyllum japonicum Sieb. Et Zucc), an endangered plant in China

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    Katsura tree (Cercidiphyllum japonicum Sieb. Et Zucc) is a long-lived, deciduous, wind-pollinated tree with dimorphic leaves. It is valued as an ornamental or a shade tree for landscape and a commercially valuable tree. Conventional propagation through seeds and cutting is not sufficient to satisfy the progressive demand. There is an exigent need to develop protocols for rapid propagation of katsura trees. This study reports an in vitro propogation of the tree. The work focused on assessing the effects of basal medium, plant growth regulators (PGRs) combination on shoot and root proliferation. Nodal sections of young shoots were used as explants. Shoot initiation, and shoot and root proliferation were carried out on basal medium and PGRs combination. The optimal response of shoot initiation was observed in woody plant medium (WPM) supplemented with 1.0 mg L−1BA and 0.01 mg L−1IBA (indole-3-butyric acid) and the percentage of shoot initiation was up to 91.66%. For proliferation of micropropagated shoots, three orthogonal designs were carried out. The result shows that the highest proliferation coefficient (4.83) was obtained in the medium containing 1.0 mg L−1 BA and 0.05 mg L−1 NAA. With the application of benzyladenine (BA) and naphthalene acetic acid (NAA), emerald green and vigorous shoots were observed. Shoots about 2.0 cm long with 4 to 6 leaves were excised and transferred to root propagation media. When the concentration of NAA was 0.5 mg L−1, the rooting percentage, mean number and mean length of roots were the highest, reaching 75% and 3.1 and 2.1 cm respectively. This efficient plant regeneration system would be helpful for genetic improvement through future conservation and biotechnology research.Keywords: Katsura tree (Cercidiphyllum japonicum Sieb. Et Zucc), shoot initiation, shoot propagation, root propagatio

    The measurement and modeling of a P2P streaming video service

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    Most of the work on grid technology in the video area has been generally restricted to aspects of resource scheduling and replica management. The traffic of such a service has a lot of characteristics in common with that of the traditional video service. However the architecture and user behavior in grid networks are quite different from those of the traditional Internet. Considering the potential of grid networks and video sharing services, measuring and analyzing P2P IPTV traffic are important and fundamental works in the field of grid networks. This paper investigates the features of PPLive, the most popular streaming service in China and based on P2P technology. Through monitoring and analyzing PPLive traffic streams, the characteristics of P2P streaming services have been studied. The analyses are carried out in respect of bearing protocols, geographical distribution and the self-similarity properties of the traffic. A streaming service traffic model has been created and verified with the simulation. The simulation results indicate that the proposed streaming service traffic model complies well with the real IPTV streaming service. It can also function as a step towards studying video-sharing services on grids

    Bisphosphonates Cause Osteonecrosis of the Jaw-Like Disease in Mice

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    Bisphosphonate-associated osteonecrosis of the jaw (BONJ) is a morbid bone disease linked to long-term bisphosphonate use. Despite its broad health impact, mechanistic study is lacking. In this study, we have established a mouse model of BONJ-like disease based on the equivalent clinical regimen in myeloma patients, a group associated with high risk of BONJ. We demonstrate that the murine BONJ-like disease recapitulates major clinical and radiographical manifestations of the human disease, including characteristic features of osseous sclerosis, sequestra, avascular, and radiopaque alveolar bone in the jaw that persists beyond a normal course of wound healing following tooth extraction. We find that long-term administration of bisphosphonates results in an increase in the size and number of osteoclasts and the formation of giant osteoclast-like cells within the alveolar bone. We show that the development of necrotic bone and impaired soft tissue healing in our mouse model is dependent on long-term use of high-dose bisphosphonates, immunosuppressive and chemotherapy drugs, as well as mechanical trauma. Most importantly, we demonstrate that bisphosphonate is the major cause of BONJ-like disease in mice, mediated in part by its ability to suppress osseous angiogenesis and bone remodeling. The availability of this novel mouse model of BONJ-like disease will help elucidate the pathophysiology of BONJ and ultimately develop novel approaches for prevention and treatment of human BONJ. Copyright © American Society for Investigative Pathology

    GsAPK, an ABA-Activated and Calcium-Independent SnRK2-Type Kinase from G. soja, Mediates the Regulation of Plant Tolerance to Salinity and ABA Stress

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    Plant Snf1 (sucrose non-fermenting-1) related protein kinase (SnRK), a subfamily of serine/threonine kinases, has been implicated as a crucial upstream regulator of ABA and osmotic signaling as in many other signaling cascades. In this paper, we have isolated a novel plant specific ABA activated calcium independent protein kinase (GsAPK) from a highly salt tolerant plant, Glycine soja (50109), which is a member of the SnRK2 family. Subcellular localization studies using GFP fusion protein indicated that GsAPK is localized in the plasma membrane. We found that autophosphorylation and Myelin Basis Protein phosphorylation activity of GsAPK is only activated by ABA and the kinase activity also was observed when calcium was replaced by EGTA, suggesting its independence of calcium in enzyme activity. We also found that cold, salinity, drought, and ABA stress alter GsAPK gene transcripts and heterogonous overexpression of GsAPK in Arabidopsis alters plant tolerance to high salinity and ABA stress. In summary, we demonstrated that GsAPK is a Glycine soja ABA activated calcium independent SnRK-type kinase presumably involved in ABA mediated stress signal transduction

    A population-based study on prevalence and risk factors of gastroesophageal reflux disease in the Tibet Autonomous Region, China

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    Objective To investigate the prevalence and risk factors of gastroesophageal reflux disease (GERD) in the Tibet Autonomous Region, China. Methods In this cross-sectional study, a stratified random sampling method was used for collecting samples in the Tibet Autonomous Region. A total of 10,000 individuals were selected from October 2016 to June 2017. A previously-published, validated questionnaire including six items related to the symptoms of GERD was used for evaluating GERD. In addition, basic demographic data, lifestyle, dietary habits, medical history and family history of GERD were investigated to identify risk factors of GERD. Results A total of 5,680 completed questionnaires were collected and analyzed. The prevalence of GERD in this area was 10.8%. Age (30–40 years vs. under 18 years, odds ratio (OR): 3.025; 40–50 years vs. under 18 years, OR: 4.484), education level (high school vs. primary, OR: 0.698; university vs. primary, OR: 2.804), ethnic group (Han vs. Tibetan, OR: 0.230; others vs. Tibetan, OR: 0.304), altitude of residence (4.0–4.5 km vs. 2.5–3.0 km, OR: 2.469), length of residence (<5 years vs. ≥5 years, OR: 2.218), Tibetan sweet tea (yes vs. no, OR: 2.158), Tibetan barley wine (yes vs. no, OR: 1.271), Tibetan dried meat (yes vs. no, OR: 1.278) and staying up late (yes vs. no, OR: 1.223) were significantly (all P < 0.05) and independently associated with GERD. Conclusions The prevalence of GERD is high in the Tibet Autonomous Region, China. Geographic conditions, ethnic group and lifestyle are risk factors for GERD
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