Oil spill models can effectively simulate the trajectories and fate of oil slicks, which is an essential element in contingency planning and effective response strategies prepared for oil spill accidents. However, whe...Oil spill models can effectively simulate the trajectories and fate of oil slicks, which is an essential element in contingency planning and effective response strategies prepared for oil spill accidents. However, when applied to offshore areas such as the Bohai Sea, the trajectories and fate of oil slicks would be affected by time-varying factors in a regional scale, which are assumed to be constant in most of the present models. In fact, these factors in offshore regions show much more variation over time than in the deep sea, due to offshore bathymetric and climatic characteristics. In this paper, the challenge of parameterizing these offshore factors is tackled. The remote sensing data of the region are used to analyze the modification of wind-induced drift factors, and a well-suited solution is established in parameter correction mechanism for oil spill models. The novelty of the algorithm is the self-adaptive modification mechanism of the drift factors derived from the remote sensing data for the targeted sea region, in respect to empirical constants in the present models. Considering this situation, a new regional oil spill model(i4Oil Spill) for the Bohai Sea is developed, which can simulate oil transformation and fate processes by Eulerian-Lagrangian methodology. The forecasting accuracy of the proposed model is proven by the validation results in the comparison between model simulation and subsequent satellite observations on the Penglai 19-3 oil spill accident. The performance of the model parameter correction mechanism is evaluated by comparing with the real spilled oil position extracted from ASAR images.展开更多
Introduction:Recently published large randomized controlled trials,START,TEMPRANO and HPTN 052 show the clinical benefit of early initiation of antiretroviral treatment(ART)in HIV-infected persons and in reducing HIV ...Introduction:Recently published large randomized controlled trials,START,TEMPRANO and HPTN 052 show the clinical benefit of early initiation of antiretroviral treatment(ART)in HIV-infected persons and in reducing HIV transmission.The trials influenced the World Health Organization(WHO)decision to issue updated recommendations to prescribe ART to all individuals living with HIV,irrespective of age and CD4 cell count.Discussion:It is clear that the new 2015 WHO recommendations if followed,will change the face of the HIV epidemic and probably curb its burden over time.Implementation however,requires that health systems,especially those in low and middle-income settings,be ready to face this challenge on a large scale.HIV prevention and treatment are easy in theory yet hard in practice.The new WHO guidelines for initiation of ART regardless of CD4 cell count will lead to upfront increases in the costs of healthcare delivery as the goal is to treat all those now newly eligible for ART.Around 22 million people living with HIV qualify and will therefore require ART.Related challenges immediately follow:firstly,that everyone must be tested for HIV;secondly,that anyone who has had an HIV test should know their result and understand its significance;and,thirdly,that every person identified as HIV-positive should receive and remain on ART.The emergence of HIV drug resistant strains when treatment is started at higher CD4 cell count thresholds is a further concern as persons on HIV treatment for longer periods of time are at increased risk of intermittent medication adherence.Conclusions:The new WHO recommendations for ART are welcome,but lacking as they fail to consider meaningful solutions to the challenges inherent to implementation.They fail to incorporate actual strategies on how to disseminate and adopt these far-reaching guidelines,especially in sub-Saharan Africa,an area with weak healthcare infrastructures.Well-designed,high-quality research is needed to assess the feasibility,safety,acceptability,impact,and cost of innovations such as the universal voluntary testing and immediate treatment approaches,and broad consultation must address community,human rights,ethical,and political concerns.展开更多
基金supported by following programs: 1) NSFC-Shandong Joint Fund for Marine Science Research Centers (Grant No. U1406404)The National High Technology Research and Development Program of China (Grant No. 2014AA09A511)+2 种基金The Scientific and Technological Innovation Project of the Qingdao National Laboratory for Marine Science and Technology (Grant No. 2015ASKJ01)International Cooperation and Exchange of the National Natural Science Foundation of China (Grant No. 61361136001)Open Fund of Key Laboratory of Marine Spill Oil Identification and Damage Assessment Technology SOA (Grant No. 201508)
文摘Oil spill models can effectively simulate the trajectories and fate of oil slicks, which is an essential element in contingency planning and effective response strategies prepared for oil spill accidents. However, when applied to offshore areas such as the Bohai Sea, the trajectories and fate of oil slicks would be affected by time-varying factors in a regional scale, which are assumed to be constant in most of the present models. In fact, these factors in offshore regions show much more variation over time than in the deep sea, due to offshore bathymetric and climatic characteristics. In this paper, the challenge of parameterizing these offshore factors is tackled. The remote sensing data of the region are used to analyze the modification of wind-induced drift factors, and a well-suited solution is established in parameter correction mechanism for oil spill models. The novelty of the algorithm is the self-adaptive modification mechanism of the drift factors derived from the remote sensing data for the targeted sea region, in respect to empirical constants in the present models. Considering this situation, a new regional oil spill model(i4Oil Spill) for the Bohai Sea is developed, which can simulate oil transformation and fate processes by Eulerian-Lagrangian methodology. The forecasting accuracy of the proposed model is proven by the validation results in the comparison between model simulation and subsequent satellite observations on the Penglai 19-3 oil spill accident. The performance of the model parameter correction mechanism is evaluated by comparing with the real spilled oil position extracted from ASAR images.
文摘Introduction:Recently published large randomized controlled trials,START,TEMPRANO and HPTN 052 show the clinical benefit of early initiation of antiretroviral treatment(ART)in HIV-infected persons and in reducing HIV transmission.The trials influenced the World Health Organization(WHO)decision to issue updated recommendations to prescribe ART to all individuals living with HIV,irrespective of age and CD4 cell count.Discussion:It is clear that the new 2015 WHO recommendations if followed,will change the face of the HIV epidemic and probably curb its burden over time.Implementation however,requires that health systems,especially those in low and middle-income settings,be ready to face this challenge on a large scale.HIV prevention and treatment are easy in theory yet hard in practice.The new WHO guidelines for initiation of ART regardless of CD4 cell count will lead to upfront increases in the costs of healthcare delivery as the goal is to treat all those now newly eligible for ART.Around 22 million people living with HIV qualify and will therefore require ART.Related challenges immediately follow:firstly,that everyone must be tested for HIV;secondly,that anyone who has had an HIV test should know their result and understand its significance;and,thirdly,that every person identified as HIV-positive should receive and remain on ART.The emergence of HIV drug resistant strains when treatment is started at higher CD4 cell count thresholds is a further concern as persons on HIV treatment for longer periods of time are at increased risk of intermittent medication adherence.Conclusions:The new WHO recommendations for ART are welcome,but lacking as they fail to consider meaningful solutions to the challenges inherent to implementation.They fail to incorporate actual strategies on how to disseminate and adopt these far-reaching guidelines,especially in sub-Saharan Africa,an area with weak healthcare infrastructures.Well-designed,high-quality research is needed to assess the feasibility,safety,acceptability,impact,and cost of innovations such as the universal voluntary testing and immediate treatment approaches,and broad consultation must address community,human rights,ethical,and political concerns.
