Search

The global Flow-following finite-volume Icosahedral Model (FIM), which was developed in the Global Systems Laboratory of NOAA/ESRL, has been coupled inline with aerosol and gas-phase chemistry schemes of different complexity using the chemistry and aerosol packages from WRF-Chem v3.7, named as FIM-Chem v1. The three chemistry schemes include 1) the simple aerosol modules from the Goddard Chemistry Aerosol Radiation and Transport model that includes only simplified sulfur chemistry, bulk aerosols, and sectional dust and sea salt modules (GOCART); 2) the photochemical gas-phase mechanism RACM coupled to GOCART to determine the impact of more realistic gas-phase chemistry on the GOCART aerosols simulations (RACM_GOCART); and 3) a further sophistication within the aerosol modules by replacing GOCART with a modal aerosol scheme that includes secondary organic aerosols (SOA) based on the VBS approach (RACM_SOA_VBS). FIM-Chem is able to simulate aerosol, gas-phase chemical species and SOA at various spatial resolutions with different levels of complexity and quantify the impact of aerosol on numerical weather predictions (NWP). We compare the results of RACM_GOCART and GOCART schemes which uses the default climatological model fields for OH, H2O2, and NO3. We find significant reductions of sulfate that are on the order of 40 % to 80 % over the eastern US and are up to 40 % near the Beijing region over China when using the RACM_GOCART scheme. We also evaluate the model performance by comparing with the Atmospheric Tomography Mission (ATom-1) aircraft measurements in 2016 summer. FIM-Chem shows good performance in capturing the aerosol and gas-phase tracers. The model predicted vertical profiles of biomass burning plumes and dust plumes off the western Africa are also reproduced reasonably well. [ABSTRACT FROM AUTHOR]

Urban bio-retention system is meaningful in reducing rainfall runoff and enhancing infiltration capacity. But the moisture migration in bio-retention systems are not clear under climate change. The spatial and temporal distribution of moisture under different rainfall events in bio-retention systems are studied in this paper based on experimental data in Beijing. Richards model is introduced to simulate the spatial and temporal distribution of moisture including pressure head, hydraulic head and water content under different initial and boundary conditions. As a result, we found that from the depth of the node to the lower boundary, the values of pressure head and hydraulic head increase with depth and decrease with time, while the values of water content represent opposite trends relative to the distribution of pressure head and hydraulic head in bio-retention systems. [ABSTRACT FROM AUTHOR]

Focuses on employees position restructuring at Peking University Library in China. Reduction of unwanted positions; Enhancement of the responsibilities of selected positions; Improvement in library services and staff morale; User expectations.

To identify risk factors associated with influenza A(H1N1)pdm09 among students in Beijing, China, we conducted a case-control study. Participants (304 case-patients and 608 controls, age range 6-19 years) were interviewed by using a standardized questionnaire. We found that in addition to vaccination, nonpharmaceutical interventions appeared to be protective. [ABSTRACT FROM AUTHOR]

The continued spread of highly pathogenic avian influenza (HPAI) viruses of H5 and H7 subtypes and low pathogenic avian influenza (LPAI) viruses of H5, H7 and H9 subtypes in birds and the subsequent infections in humans pose an ongoing pandemic threat. It has been proposed that poultry workers are at higher risk of exposure to HPAI or LPAI viruses and subsequently infection due to their repeated exposure to chickens or domestic waterfowl. The aim of this study was to examine the seroprevalence of antibodies against H5, H7 and H9 viruses amongst duck-related workers in Beijing, China and the risk factors associated with seropositivity. In March, 2011, 1741 participants were recruited from (1) commercial duckbreeding farms; (2) private duck-breeding farms; and (3) duck-slaughtering farms. Local villagers who bred ducks in their backyards were also recruited. A survey was administered by face-to-face interview, and blood samples were collected from subjects for antibody testing against H5, H7 and H9 viruses. We found that none of the subjects were seropositive for either H5 or H7 viruses, and only 0.7% (12/1741) had antibody against H9. A statistically significant difference in H9 antibody seroprevalence existed between the various categories of workers (P = 0.005), with the highest figures recorded amongst the villagers (1.7%). Independent risk factors associated with seropositivity toinfection with H9 virus included less frequent disinfection of worksite (OR, 5.13 [95% CI, 1.07-24.58]; P = 0.041; ≤ twice monthly versus>twice monthly) and handling ducks with wounds on hands (OR, 4.13 [95% CI, 1.26-13.57]; P = 0.019). Whilst the risk of infection with H5, H7 and H9 viruses appears to be low among duck-related workers in Beijing, China, ongoing monitoring of infection with the H9 virus is still warranted, especially amongst villagers who breed backyard ducks to monitor for any changes. [ABSTRACT FROM AUTHOR]

Aim: To measure the size of the neuroretinal rim, the major variable in the quantitative analysis of the optic nerve head, and its correlations in adult Chinese in a population based setting. Methods: The Beijing eye study-a population based, cross sectional cohort study-included 4439 subjects from among 5324 of age of 40+years invited to participate (response rate 83.4%). This study included a random sample of 781 subjects with normal intraocular pressure (lOP), normal visual fields, and a normal optic nerve head; and a random sample of 84 subjects with an IOP >21 mm Hg. Colour optic disc photographs (300) were examined morphometrically. Results: In the normal group, the mean (SD) neuroretinal rim area was 1.70 (0.30) mm2. It was significantly correlated with optic disc area (rim area =0.43∗disc area+0.67; p<0.001). It was not significantly associated with age, sex, or a known diagnoses of diabetes mellitus, arterial hypertension or hypotension, hyperlipidaemia, coronary heart disease, or cerebral haemorrhage. Conclusions: In adult Chinese, the neuroretinal rim area measures, 1.70 (0.30) mm2 on optic disc photographs. It is statistically independent of age. Compared with data from studies in Western countries, the neuroretinal rim is larger in adult Chinese than in adult white populations, corresponding to a larger optic disc size in the Chinese. [ABSTRACT FROM AUTHOR]