Temperature variations at the Great Wall and Zhongshan stations

Surface meteorological observations have been carried out at the Great Wall station (GW) and Zhongshan station (ZS) from 1984 to 2008 and from 1989 to 2008 respectively. The variation in mean air temperature and its trends are derived from the meteorological observation data recorded at both stations. The warming rate of the annual mean temperature at GW is similar to that at Bellingshausen station, which is about 3 km distant. Thus, the warming trend is representative of the King George Island region. The warming rate of ZS is less different from that at Davis station, which is about 100 km from ZS. It can be said that the meteorological data recorded at both stations are representative of the regions of the King George Island and east coast of the Antarctic

Asymmetric properties between the forward and backward stimulated emission generated by ultrafast three- and four-photon excitation

This paper presents the observation of asymmetric behavior between the forward and backward stimulated emission, generated in multiphoton active dye solutions, through three- or four-photon excitation of subpicosecond laser pulses. At a pump energy level considerably higher than the lasing threshold value, the peak wavelengths of the forward stimulated emission are 20–30-nm shorter than those of the backward stimulated emission for the two investigated stilbazolium dye solutions (PRL-L3 and PRL-L10). This obvious spectral asymmetry can be explained by the following three considerations: (i) the difference of spatial/temporal sequences between the forward and backward stimulated emission pulses; (ii) blueshift of the peak wavelength of transient gain experienced by the forward stimulated emission pulse; and (iii) saturation of reabsorption at the forward lasing wavelength range. These proposed explanations are verified by a specially designed pump-probe experiment, utilizing a white-light continuum as the probe beam and the ∼1300-nm laser radiation as the pump beam for three-photon excitation. The experimental results have clearly shown the existence of the saturation effect of reabsorption and the gain-peak blueshift effect as well as their transient features

Measurement and analysis of ozone, ultraviolet B and aerosol light scattering coefficients in the Arctic

Tropospheric ozone (O3), ultraviolet B (UVB) radiation and aerosol light scattering coefficients (SC) were investigated on a cruise ship during the fourth Chinese National Arctic Research Expedition from July 1 - September 20, 2010. The results showed that O3, UVB and SC decreased with increasing latitude, with minimum values recorded in the central Arctic Ocean. Average O3 concentrations were 15.9 ppbv and 15.1 ppbv in the Bering Sea and Arctic Ocean, respectively. Ozone concentrations increased to 17.5 ppbv in the high Arctic region. Average UVB values were 0.26 W * m(-2) and 0.14 W * m(-2) in the Bering Sea and Arctic Ocean, respectively. The average SC in the Bering Sea was 4.3 M * m(-1), more than twice the value measured in the Arctic Ocean, which had an average value of 1.7 M * m(-1). Overall, UVB and SC values were stable in the central Arctic Ocean

Sleep duration and patterns in Chinese older adults: A comprehensive meta-analysis

This meta-analysis examined the mean sleep duration and patterns in Chinese older adult population. A literature search was systematically conducted covering major English (PubMed, Embase and PsycINFO) and Chinese (Chinese National Knowledge Infrastructure (CNKI), WanFang and SinoMed) databases. Data in studies with the mean and standard deviation of sleep duration and/or the proportion of short and long sleep durations in Chinese older adults were extracted and pooled using random-effects models. Subgroup analyses were conducted according to gender, region, area, survey time and sample size. A total of 36 studies with 150,616 subjects were included for analyses. The pooled mean sleep duration of 21 studies with available data was 6.82 hours/day (95% CI: 6.59–7.05 hours/day). The estimated proportions of sleep duration \u3c5 hours/day, \u3c6 hours/day, \u3c7 hours/day were 18.8% (95% CI: 1.7%–35.9%), 26.7% (95% CI: 19.7%–33.7%) and 42.3% (95% CI: 34.8%–49.8%), respectively. The pooled proportions for long sleepers were 22.6% (95% CI: 13.9%–31.4%) (\u3e8 hours/day) and 17.6% (95% CI: 12.4%–22.9%) (\u3e9 hours/day). Given the adverse effects of unhealthy sleep patterns, health professionals should pay more attention to sleep patterns in this population in China

On board measurement of black carbon aerosols over the Arctic Ocean in summer

This paper presents aerosol black carbon (BC) concentrations measured at deck level on board the R/V XUE LONG icebreaker. The vessel cruised the Arctic Ocean carrying an in situ aethalometer during the summers of 2008 and 2010. The courses of the third Chinese National Arctic Research Expedition (3rd CHINARE - Arctic, August 2008) and fourth Chinese National Arctic Research Expedition (4th CHINARE-Arctic, from late July to August 2010) were bounded by 173°W - 143°W and 178°E - 150°W, with northernmost points 85°250N and 88°260N, respectively. Results show low surface BC concentrations over the ocean throughout the courses, with means (standard error) of 6.0 (±4.7) ng * m(-3) for 3rd CHINARE-Arctic, and 8.4(±7.1) ng * m(-3) for 4th CHINARE- Arctic. It is clear that these onboard BC concentrations are similar to reported data from coastal stations in the Arctic region. The latitude-average BC concentration varied from 3.0 - 26.2 ng * m(-3) for 3rd CHINARE-Arctic, to 4.2 - 20.5 ng * m(-3) for 4th CHINARE-Arctic. At latitudes higher than 72°N for 3rd CHINARE-Arctic and 75°N for 4th CHINARE-Arctic, BC concentrations were lower and had negligible latitudinal gradients. Analysis indicates that the presence of the Arctic front isolates the lower atmosphere of the high-latitude Arctic Ocean from low-latitude terrestrial transport. This maintains the very low BC concentrations and negligible concentration gradients at high latitudes of the Arctic Ocean during summer. Calculated airmass backward trajectories for the two expeditions show that the Arctic front in 2010 was further north than in 2008, which caused different latitudinal variation of BC concentration in the two years