2,132 research outputs found

    Understanding Relationships Between the 1998 Yangtze River Flood and Northeast Eurasian Blocking

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    Severe summer monsoon flooding occurred along the Yangtze River Valley (YRV) in 1998. The heaviest precipitation fell during June 8-23 and July 20-29 and coincided with midtropospheric blocking over northeast Eurasia. An index based on the difference between Okhotsk High and west Pacific Low intensity is developed in this study to quantify blocking; analysis shows that blocking and equatorward displacement of the upper-tropospheric east Asian jet preceded (accompanied) the June (July) period. This suggests that heavy rainfall during each interval was caused by different atmospheric processes. An examination of joint variations in the index and YRV precipitation during 1958-1998 revealed several periods similar to those identified in 1998. However, the exceptional magnitude of the blocking and rainfall during 1998 made the June and July events unique. During June 8-23, blocking collapsed and the jet retreated to its climatological position (approximately 35degreesN) prior to heavy rainfall occurrence. The background vertical ascent of the jet-induced thermally direct circulation over the YRV was then enhanced by mid-tropospheric short-wave troughs that caused increased coupling between the lower- and upper-tropospheric circulations. In contrast, July 20-29 precipitation increased in response to intensification and anomalous equatorward displacement of the jet to a position just north of the YRV. Diminished mid-tropospheric ridging over central China further strengthened vertical ascent over the YRV. During both periods, the regional circulation acted to enhance tropical moisture transport, which, in turn, aided in precipitation production along the YRV

    Final Report for the portion performed in the University of Illinois on the project entitled "Optimizing the Cloud-Aerosol-Radiation Ensemble Modeling System to Improve Future Climate Change Projections at Regional to Local Scales"

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    This is the final report for the closure of the research tasks on the project that have performed during the entire reporting period in the University of Illinois. It contains a summary of the achievements and details of key results as well as the future plan for this project to be continued in the University of Maryland

    Structural Stability of Lexical Semantic Spaces: Nouns in Chinese and French

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    Many studies in the neurosciences have dealt with the semantic processing of words or categories, but few have looked into the semantic organization of the lexicon thought as a system. The present study was designed to try to move towards this goal, using both electrophysiological and corpus-based data, and to compare two languages from different families: French and Mandarin Chinese. We conducted an EEG-based semantic-decision experiment using 240 words from eight categories (clothing, parts of a house, tools, vehicles, fruits/vegetables, animals, body parts, and people) as the material. A data-analysis method (correspondence analysis) commonly used in computational linguistics was applied to the electrophysiological signals. The present cross-language comparison indicated stability for the following aspects of the languages' lexical semantic organizations: (1) the living/nonliving distinction, which showed up as a main factor for both languages; (2) greater dispersion of the living categories as compared to the nonliving ones; (3) prototypicality of the \emph{animals} category within the living categories, and with respect to the living/nonliving distinction; and (4) the existence of a person-centered reference gradient. Our electrophysiological analysis indicated stability of the networks at play in each of these processes. Stability was also observed in the data taken from word usage in the languages (synonyms and associated words obtained from textual corpora).Comment: 17 pages, 4 figure

    Experimental study on penetration of dental implants into the maxillary sinus in different depths

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    The exposing of dental implant into the maxillary sinus combined with membrane perforation might increase risks of implant failure and sinus complications. Objective: The purpose of this study was to investigate the effects of the dental implant penetration into the maxillary sinus cavity in different depths on osseointegration and sinus health in a dog model. Material and Methods: Sixteen titanium implants were placed in the bilateral maxillary molar areas of eight adult mongrel dogs, which were randomly divided into four groups according to the different penetrating extents of implants into the sinus cavities (group A: 0 mm; group B: 1 mm; group C: 2 mm; group D: 3 mm). The block biopsies were harvested five months after surgery and evaluated by radiographic observation and histological analysis. Results: No signs of inflammatory reactions were observed in any maxillary sinus of the eight dogs. The tips of the implants with penetrating depth of 1 mm and 2 mm were found to be fully covered with newly formed membrane and partially with new bone. The tips of the implants with penetrating depth over 3 mm were exposed in the sinus cavity and showed no membrane or bone coverage. No significant differences were found among groups regarding implant stability, bone-to-implant contact (BIC) and bone area in the implant threads (BA). Conclusions: Despite the protrusion extents, penetration of dental implant into the maxillary sinus with membrane perforation does not compromise the sinus health and the implant osseointegration in canine

    Discovery of gamma-ray emission from a strongly lobe-dominated quasar 3C 275.1

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    We systematically analyze the 6-year {\it Fermi}/LAT data of the lobe-dominated quasars (LDQs) in the complete LDQ sample from 3CRR survey and report the discovery of high-energy γ\gamma-ray emission from 3C 275.1. The γ\gamma-ray emission of 3C 207 is confirmed and significant variability of the lightcurve is identified. We do not find statistically significant γ\gamma-ray emission from other LDQs. 3C 275.1 is the known γ\gamma-ray quasar with the lowest core dominance parameter (i.e., R=0.11R=0.11). We also show that both the northern radio hotspot and parsec jet models can reasonably reproduce the γ\gamma-ray data. The parsec jet model, however, is favored by the potential γ\gamma-ray variability at the timescale of months. We suggest that some dimmer γ\gamma-ray LDQs will be detected in the future and LDQs could contribute non-negligibly to the extragalactic γ\gamma-ray background.Comment: 26 pages, 10 figures, 3 tables; ApJ in pres
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