Influence of regional-scale anthropogenic emissions on CO2 distributions over the western North Pacific

We report here airborne measurements of atmospheric CO2 over the western North Pacific during the March-April 2001 Transport and Chemical Evolution over the Pacific (TRACE-P) mission. The CO2 spatial distributions were notably influenced by cyclogenesis-triggered transport of regionally polluted continental air masses. Examination of the CO2 to C2H2/CO ratio indicated rapid outflow of combustion-related emissions in the free troposphere below 8 km. Although the highest CO2 mixing ratios were measured within the Pacific Rim region, enhancements were also observed further east over the open ocean at locations far removed from surface sources. Near the Asian continent, discrete plumes encountered within the planetary boundary layer contained up to 393 ppmv of CO2. Coincident enhancements in the mixing ratios of C2Cl4, C2H2, and C2H4 measured concurrently revealed combustion and industrial sources. To elucidate the source distributions of CO2, an emissions database for Asia was examined in conjunction with the chemistry and 5-day backward trajectories that revealed the WNW/W sector of northeast Asia was a major contributor to these pollution events. Comparisons of NOAA/CMDL and JMA surface data with measurements obtained aloft showed a strong latitudinal gradient that peaked between 35° and 40°N. We estimated a net CO2 flux from the Asian continent of approximately 13.93 Tg C day-1 for late winter/early spring with the majority of the export (79%) occurring in the lower free troposphere (2-8 km). The apportionment of the flux between anthropogenic and biospheric sources was estimated at 6.37 Tg C day-1 and 7.56 Tg C day-1, respectively

Large-scale molecular dynamics simulation of magnetic properties of amorphous iron under pressure

Author name used in this publication: C. H. Woo2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Quality of Care for Older Patients with Non-Cancer Diagnoses under the End-of-Life Care Program

Background: End-of-life (EOL) care is an important part of geriatric medicine in view of rapidly ageing populations in the world. Aim: We aimed to evaluate the quality of care for older patients with non-cancer terminal illnesses, who died in 2010, under the EOL care program of an academic medical unit in Hong Kong. This unit consisted of an acute hospital, Prince of Wales Hospital (PWH) and a convalescence hospital (Shatin Hospital, SH). Methods: This was a retrospective hospital-based audit of clinical effectiveness of the EOL service. We reviewed the quality of patient care during the final seven days of life. The quality of care was evaluated based on the compliance rates of five selected goals and the adoption of futile life-sustaining procedures and treatments. Results: Case records of 129 patients in the EOL care program were analyzed. Two goals, including minimization of regular monitoring of vital signs and no blood taking, achieved over 70% compliance at SH and 0% at PWH. The compliance rates of discontinuation of non-essential medications were 46.4% in SH and 47.1% in PWH; and the compliance rates of switching essential medications to non-oral routes were 63.4% in SH and 70.6% in PWH (not statistically significant). The compliance rates of using as-required intravenous or subcutaneous medications were extremely low (<2%) at both hospitals. All futile life-sustaining procedures and treatments were initiated at the PWH. Conclusions: We demonstrated significant differences in the quality of EOL care between the acute hospital and convalescence hospital. Greater emphasis on specialist training and education with allocation of resources may improve the EOL care in both settings.published_or_final_versio

Electronic structure of the electron-doped cuprate superconductors

Within the framework of the kinetic energy driven d-wave superconductivity, the electronic structure of the electron doped cuprate superconductors is studied. It is shown that although there is an electron-hole asymmetry in the phase diagram, the electronic structure of the electron-doped cuprates in the superconducting-state is similar to that in the hole-doped case. With increasing the electron doping, the spectral weight in the $(\pi,0)$ point increases, while the position of the superconducting quasiparticle peak is shifted towards the Fermi energy. In analogy to the hole-doped case, the superconducting quasiparticles around the $(\pi,0)$ point disperse very weakly with momentum.Comment: 8 pages, 3 figures, accepted for publication in Phys. Lett.

Evaluating regional emission estimates using the TRACE-P observations

Measurements obtained during the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) experiment are used in conjunction with regional modeling analysis to evaluate emission estimates for Asia. A comparison between the modeled values and the observations is one method to evaluate emissions. Based on such analysis it is concluded that the inventory performs well for the light alkanes, CO, ethyne, SO2, and NOₓ. Furthermore, based on model skill in predicting important photochemical species such as O₃, HCHO, OH, HO₂, and HNO₃, it is found that the emissions inventories are of sufficient quality to support preliminary studies of ozone production. These are important finding in light of the fact that emission estimates for many species (such as speciated NMHCs and BC) for this region have only recently been estimated and are highly uncertain. Using a classification of the measurements built upon trajectory analysis, we compare observed species distributions and ratios of species to those modeled and to ratios estimated from the emissions inventory. It is shown that this technique can reconstruct a spatial distribution of propane/benzene that looks remarkably similar to that calculated from the emissions inventory. A major discrepancy between modeled and observed behavior is found in the Yellow Sea, where modeled values are systematically underpredicted. The integrated analysis suggests that this may be related to an underestimation of emissions from the domestic sector. The emission is further tested by comparing observed and measured species ratios in identified megacity plumes. Many of the model derived ratios (e.g., BC/CO, SOₓ/C₂H₂) fall within ∼25% of those observed and all fall outside of a factor of 2.5. (See Article file for details of the abstract.)Department of Civil and Environmental EngineeringAuthor name used in this publication: Wang, T