52 research outputs found
A Train-Like Extreme Multiple Tropical Cyclogenesis Event in the Northwest Pacific in 2004
Using observed data sets, an unprecedented multiple tropical cyclogenesis event over the northwest Pacific is identified, with seven tropical cyclones forming in sequence from 6 August to 10 September 2004. In this event, the preexisting tropical cyclones (TCs) generated the alternating cyclonic and anticyclonic disturbances in their wake region by exciting Rossby waves. The cyclonic disturbances subsequently intensified into new TCs within the monsoon trough, which was likely enhanced by anomalous warming in the tropical central Pacific and cooling in the tropical Indian Ocean, so that it lasted long enough to allow seven TCs to develop consecutively. An analysis of the historical records during 1979–2014 substantiates such linkage of the occurrence of this extreme multiple tropical cyclogenesis event to the anomalous sea surface temperature pattern and the monsoon trough. This result has important implications regarding the prediction of the multiple cyclogenesis events
Long-term trends in tropical cyclone tracks around Korea and Japan in late summer and early fall
This study investigates long-term trends in tropical cyclones (TCs) over the extratropical western North Pacific (WNP) over a period of 35 years (1982-2016). The area analyzed extended across 30-45 degrees N and 120-150 degrees E, including the regions of Korea and Japan that were seriously affected by TCs. The northward migration of TCs over the WNP to the mid-latitudes showed a sharp increase in early fall. In addition, the duration of TCs over the WNP that migrated northwards showed an increase, specifically in early to mid-September. Therefore, more recently, TC tracks have been observed to significantly extend into the mid-latitudes. The recent northward extension of TC tracks over the WNP in early fall was observed to be associated with changes in environmental conditions that were favorable for TC activities, including an increase in sea surface temperature (SST), decrease in vertical wind shear, expansion of subtropical highs, strong easterly steering winds, and an increase in relative vorticity. In contrast, northward migrations of TCs to Korea and Japan showed a decline in late August, because of the presence of unfavorable environmental conditions for TC activities. These changes in environmental conditions, such as SST and vertical wind shear, can be partially associated with the Pacific decadal oscillation
Operation and performance of the ATLAS semiconductor tracker
The semiconductor tracker is a silicon microstrip detector forming part of the inner tracking system of the ATLAS experiment at the LHC. The operation and performance of the semiconductor tracker during the first years of LHC running are described. More than 99% of the detector modules were operational during this period, with an average intrinsic hit efficiency of (99.74±0.04)%. The evolution of the noise occupancy is discussed, and measurements of the Lorentz angle, δ-ray production and energy loss presented. The alignment of the detector is found to be stable at the few-micron level over long periods of time. Radiation damage measurements, which include the evolution of detector leakage currents, are found to be consistent with predictions and are used in the verification of radiation background simulations
Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo
Despite the growing number of binary black hole coalescences confidently observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include the effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that have already been identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total source-frame mass M > 70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz emitted gravitational-wave frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place a conservative upper limit for the merger rate density of high-mass binaries with eccentricities 0 < e ≤ 0.3 at 16.9 Gpc−3 yr−1 at the 90% confidence level
The effect of tooth and foundation restoration heights on the load fatigue performance of cast crowns
10.1016/S0022-3913(10)60147-3Journal of Prosthetic Dentistry1045318-324JPDE
Cardiomyopathy in paediatrics
Journal of the Singapore Paediatric Society331-240-44SPSJ
Quantification of 3-deazaneplanocin A, a novel epigenetic anticancer agent, in rat biosamples by hydrophilic interaction liquid chromatography-tandem mass spectrometric detection
10.1016/j.jchromb.2010.12.009Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences8793-4285-290JCBA
Humor attenuates the cortisol awakening response in healthy older men
This study examined the impact of an important factor contributing to successful aging, humor, on post-awakening cortisol levels among a group of 45 older men whose ages ranged from 64 years to 86 years (mean = 73.6 years). Four saliva samples were collected from the participants for 2 days immediately after waking and every 15 min thereafter for three times. Cortisol data of the 2 days were aggregated for analysis. Two separate indices of cortisol awakening response reflecting the mean level of secretion and the rise from immediately to 45 min post-awakening, AUCG and AUCI, were computed using the trapezoid formula. The relation of these two indices to humor (operationalized as coping) was examined in a multiple regression analysis while controlling for the effect of age, socioeconomic status, and self-esteem. Results indicated that higher humor scores were associated with lower AUCG but had no relation with AUCI. Findings of the present study suggest that the hypothalamic-pituitary-adrenocortical axis is the major pathway whereby positive psychological dispositions, such as humor, exert their health effects in the aging population. Moreover, cortisol levels in the awakening period may be particularly sensitive to the influences of psychosocial factors
Major factors of global and regional monsoon rainfall changes: natural versus anthropogenic forcing
© 2020 The Author(s). Published by IOP Publishing Ltd.A number of studies have investigated the mechanisms that determine changes in precipitation, including how a wet region gets wetter. However, not all monsoon areas get wetter - there is a need to understand the major factors behind changes in regional monsoon precipitation, in terms of external forcing and internal variabilities in the last six decades by a combination of different observed datasets and model runs. We have found that time of emergence of anthropogenic signals is robustly detected in the northern African monsoon before the 1990s with the use of the CESM Large Ensemble Project. From CMIP5 model runs and three reanalysis datasets, the results found are that the change in rainfall over African monsoon (AFM) is mainly due to anthropogenic forcing and that over Asian-Australian monsoon (AAM) is affected by internal variability. Moreover, the cause of American monsoon (AMM) rainfall change cannot be known due to a discrepancy among observed datasets. Here we show that the asymmetry between Northern Hemisphere (NH) and Southern Hemisphere (SH) parts by green-house gas (GHG) is detected over the AFM and AAM regions. However, the land monsoon rainfall in the northern AMM is decreased by a combination of GHG and aerosol forcing. In general, the aerosol forcing causes a decreasing rainfall over the monsoon regions. In future projection, the land rainfall over the AAM and AMM are expected to increase and decrease in the future from most models' results. The asymmetry between an increase in NH and a decrease in SH is dominant in the future from most models' future simulation results, which is well shown over the AFM and AAM. This study suggests that the physical process of GHG and aerosol effects in rainfall should be explored in the context of regional aspects11Nsciescopu
- …