Efficient biological carbon export to the mesopelagic ocean induced by submesoscale fronts.

Oceanic submesoscale processes are ubiquitous in the North Pacific Subtropical Gyre (NPSG), where the biological carbon pump is generally ineffective. Due to difficulties in collecting continuous observations, however, it remains uncertain whether episodic submesoscale processes can drive significant changes in particulate organic carbon (POC) export into the mesopelagic ocean. Here we present observations from high-frequency Biogeochemical-Argo floats in the NPSG, which captured the enhanced POC export fluxes during the intensifying stages of a submesoscale front and a cyclonic eddy compared to their other life stages. A higher percentage of POC export flux was found to be transferred to the base of mesopelagic layer at the front compared to that at the intensifying eddy and the mean of previous studies (37% vs. ~10%), suggesting that the POC export efficiency was significantly strengthened by submesoscale dynamics. Such findings highlight the importance of submesoscale fronts for carbon export and sequestration in subtropical gyres.

Assessing pollution-related effects of oil spills from ships in the Chinese Bohai Sea.

An analysis of the effects of potential oil spills will provide data in support of decisions related to improving the response to oil spills and its emergency management. We selected the Chinese Bohai Sea, especially the Bohai Strait, as our investigation region to provide an assessment of the effects of pollution from ship-related oil spills on adjacent coastal zones. Ship-related accidents are one of the major factors causing potential oil spills in this area. A three dimensional oil transport and transformation model was developed using the Estuary, Coastal, and Ocean Model. This proposed model was run 90 times and each run lasted for 15days to simulate the spread and weathering processes of oil for each of four potential spill sites, which represented potential sites of ship collisions along heavy traffic lanes in the Bohai Sea. Ten neighboring coastal areas were also considered as target zones that potentially could receive pollutants once oil spilled in the study areas. The statistical simulations showed that spills in winter were much worse than those in summer; they resulted in very negative effects on several specific target zones coded Z7, Z8, Z9, and Z10 in this paper. In addition, sites S3 (near the Penglai city) and S4 (near the Yantai city) were the two most at-risk sites with a significantly high probability of pollution if spills occurred nearby during winter. The results thus provided practical guidelines for local oil spill prevention, as well as an emergency preparedness and response program.

Prevalence of dementia and mild cognitive impairment in the elderly living in nursing and veteran care homes in Xi'an, China.

DESIGN: Cross-sectional surveys using cluster sampling. OBJECTIVES: To explore the prevalence of dementia and mild cognitive impairment (MCI) in several nursing homes (NHs) and veteran care homes (VCHs) in Xi'an City and their various risk factors. PARTICIPANTS AND MEASUREMENTS: 264 native elderly people from four NHs and two VCHs were examined with several screening tests for dementia: Mini Mental State Examination (MMSE), Activities of Daily Living (ADL) and Hasegawa Dementia Scale (HDS). Diagnosis of dementia and MCI were made according to DSM-III-R and Petersen's criteria. Socio-demographic characteristics and past history were also collected. RESULTS: Dementia prevalence was 36.7% in those living in NHs and VCHs, much higher than that of normal population and the prevalence of MCI was 13.3% which was the same as in normal population. Dementia was associated with old age, female, low education level and living in NHs. Men had significantly higher prevalence odds for MCI. Very old age, living in NHs and severe ADL impairment were correlated with higher prevalence odds for dementia and MCI. CONCLUSION: The prevalence of dementia in the elderly living in groups in Xi'an was high, especially living in NHs.