116 research outputs found

    Analysis of contrast sensitivity on examination for pilots

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    AIM: To study the influential factors of the contrast sensitivity function(CSF), we tested and investigated the CSF of navy pilots. METHODS: Totally 58 pilots(116 eyes)were examined by CSF under the nighttime, nighttime & periglare, daytime, daytime & periglare conditions for 5 spacial frequencies with OPTEC6 500 Vision Tester. RESULTS: From mean diagram of curves, the peak of CSF under the nighttime, nighttime & periglare conditions was at 3-6c/d, daytime, daytime & periglare conditions was at 6c/d. CONCLUSION: The distant CSF is better than the near CSF in navy pilots,the binoculus CSF is better than that of the single eye. The spatial characteristics of CSF in navy pilots were reflected by present study

    A culture of conservation: How an ancient forest plantation turned into an old-growth forest reserve – The story of the Wamulin forest

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    The global expansion of forest plantations at the expense of natural forests, especially old-growth forests, raises concerns about habitat loss and a decline in ecosystem services. Natural regeneration of second-growth forests with minimal human assistance has been suggested as a cost-effective way to restore forests and increase forest ecosystem service potential. However, it is unclear whether natural regeneration will lead to the development of second-growth forests similar to natural forests because most naturally regenerated second-growth forests are still young. We present a case study of a very old second-growth forest in southeastern China in which a forest plantation established approximately six centuries ago has now developed into an old forest with extraordinary high biodiversity levels, an immense carbon pool, and a rich culture. The forest was established in the 14th century because of a charitable contribution, became protected under the Chinese cultural norm of ‘unity between humans and the nature’, and was conserved because of the belief that the prosperity of people is closely linked to the prosperity of trees. The recent designation of the forest as a nature reserve further protects it from development despite competing land-use demands related to recent economic growth. This case illustrates that, although human activity is the main cause for the disappearance and degradation of many forests, when human interests and cultural values align second-growth restoration and subsequent forest conservation can lead to the successional development of old-growth forests. Because this development takes multiple centuries, the protection of current second-growth forests within conservation easements (e.g. nature reserves) and the reformation of culture values for the linkage of forests to human well-being are key aspects of the continued conservation-aided succession of second-growth forests. A free Plain Language Summary can be found within the Supporting Information of this article

    Evaluation of the Surface Urban Energy and Water balance Scheme (SUEWS) at a dense urban site in Shanghai: sensitivity to anthropogenic heat and irrigation

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    The Surface Urban Energy and Water balance Scheme (SUEWS) is used to investigate the impact of anthropogenic heat flux (QF) and irrigation on surface energy balance partitioning in a central business district of Shanghai. Diurnal profiles of QF are carefully derived based on city-specific hourly electricity consumption data, hourly traffic data and dynamic population density. QF is estimated to be largest in summer (mean daily peak 236 W m-2). When QF is omitted, the SUEWS sensible heat flux (QH) reproduces the observed diurnal pattern generally well, but the magnitude is underestimated compared to observations for all seasons. When QF is included, the QH estimates are improved in spring, summer and autumn, but poorer in winter indicating winter QF is overestimated. Inclusion of QF has little influence on the simulated latent heat flux (QE), but improves the storage heat flux estimates except in winter. Irrigation, both amount and frequency, has a large impact on QE. When irrigation is not considered, the simulated QE is underestimated for all seasons. The mean summer daytime QE is largely overestimated compared to observations under continuous irrigation conditions. Model results are improved when irrigation occurs with a 3-day frequency, especially in summer. Results are consistent with observed monthly out-door water use. This study highlights the importance of appropriately including the QF and irrigation in urban land surface models - terms not generally considered in many previous studies

    East Asian Study of Tropospheric Aerosols and their Impact on Regional Clouds, Precipitation, and Climate (EAST-AIR_(CPC))

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    Aerosols have significant and complex impacts on regional climate in East Asia. Cloud‐aerosol‐precipitation interactions (CAPI) remain most challenging in climate studies. The quantitative understanding of CAPI requires good knowledge of aerosols, ranging from their formation, composition, transport, and their radiative, hygroscopic, and microphysical properties. A comprehensive review is presented here centered on the CAPI based chiefly, but not limited to, publications in the special section named EAST‐AIRcpc concerning (1) observations of aerosol loading and properties, (2) relationships between aerosols and meteorological variables affecting CAPI, (3) mechanisms behind CAPI, and (4) quantification of CAPI and their impact on climate. Heavy aerosol loading in East Asia has significant radiative effects by reducing surface radiation, increasing the air temperature, and lowering the boundary layer height. A key factor is aerosol absorption, which is particularly strong in central China. This absorption can have a wide range of impacts such as creating an imbalance of aerosol radiative forcing at the top and bottom of the atmosphere, leading to inconsistent retrievals of cloud variables from space‐borne and ground‐based instruments. Aerosol radiative forcing can delay or suppress the initiation and development of convective clouds whose microphysics can be further altered by the microphysical effect of aerosols. For the same cloud thickness, the likelihood of precipitation is influenced by aerosols: suppressing light rain and enhancing heavy rain, delaying but intensifying thunderstorms, and reducing the onset of isolated showers in most parts of China. Rainfall has become more inhomogeneous and more extreme in the heavily polluted urban regions

    East Asian Study of Tropospheric Aerosols and their Impact on Regional Clouds, Precipitation, and Climate (EAST-AIR_(CPC))

    Get PDF
    Aerosols have significant and complex impacts on regional climate in East Asia. Cloud‐aerosol‐precipitation interactions (CAPI) remain most challenging in climate studies. The quantitative understanding of CAPI requires good knowledge of aerosols, ranging from their formation, composition, transport, and their radiative, hygroscopic, and microphysical properties. A comprehensive review is presented here centered on the CAPI based chiefly, but not limited to, publications in the special section named EAST‐AIRcpc concerning (1) observations of aerosol loading and properties, (2) relationships between aerosols and meteorological variables affecting CAPI, (3) mechanisms behind CAPI, and (4) quantification of CAPI and their impact on climate. Heavy aerosol loading in East Asia has significant radiative effects by reducing surface radiation, increasing the air temperature, and lowering the boundary layer height. A key factor is aerosol absorption, which is particularly strong in central China. This absorption can have a wide range of impacts such as creating an imbalance of aerosol radiative forcing at the top and bottom of the atmosphere, leading to inconsistent retrievals of cloud variables from space‐borne and ground‐based instruments. Aerosol radiative forcing can delay or suppress the initiation and development of convective clouds whose microphysics can be further altered by the microphysical effect of aerosols. For the same cloud thickness, the likelihood of precipitation is influenced by aerosols: suppressing light rain and enhancing heavy rain, delaying but intensifying thunderstorms, and reducing the onset of isolated showers in most parts of China. Rainfall has become more inhomogeneous and more extreme in the heavily polluted urban regions

    Surgical outcomes of hepatocellular carcinoma with extrahepatic bile duct tumor thrombus: a multicenter study

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    BackgroundThe long-term prognosis after surgery of patients with hepatocellular carcinoma (HCC) and extrahepatic bile duct tumor thrombus (Ex-BDTT) remains unknown. We aimed to identify the surgical outcomes of patients with HCC and Ex-BDTT.MethodsA total of 138 patients with Ex-BDTT who underwent hepatectomy with preservation of the extrahepatic bile duct from five large hospitals in China between January 2009 and December 2017 were included. The Cox proportional hazards model was used to analyze overall survival (OS) and recurrence-free survival (RFS).ResultsWith a median follow-up of 60 months (range, 1–127.8 months), the median OS and RFS of the patients were 28.6 and 8.9 months, respectively. The 1-, 3-, and 5-year OS rates of HCC patients with Ex-BDTT were 71.7%, 41.2%, and 33.5%, respectively, and the corresponding RFS rates were 43.5%, 21.7%, and 20.0%, respectively. Multivariate analysis identified that major hepatectomy, R0 resection, and major vascular invasion were independent prognostic factors for OS and RFS. In addition, preoperative serum total bilirubin ≄ 4.2 mg/dL was an independent prognostic factor for RFS.ConclusionMajor hepatectomy with preservation of the extrahepatic bile duct can provide favorable long-term survival for HCC patients with Ex-BDTT
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