The amount of human-caused environmental impact can be evaluated by the degree of pollution. Active coastal marine environmental exploitation has given rise to another problem： marine litter. The period of time allow...The amount of human-caused environmental impact can be evaluated by the degree of pollution. Active coastal marine environmental exploitation has given rise to another problem： marine litter. The period of time allowing to evaluate the change in the degree of the shore pollution with litter is that from 1999 till 2014. Litter can be classified both by qualitative and quantitative character. Regarding qualitative character litter is divided into organic substance （garbage, wood） and non-organic substance （glass, plastics, rubber, metal）. As to the size there are three categories： small, middle, large. As to small litter it is still predominating in the litter structure of the shoreline pollution but its average amount has been decreased significantly. As to the litter distribution, it is mostly concentrated within the beach zone. It is thus natural to assume the land-based origin of the litter, such as litter brought by holiday-makers or introduced by nearby enterprises.展开更多
Predicting the future course of an epidemic depends on being able to estimate the current numbers of infected individuals.However,while back-projection techniques allow reliable estimation of the numbers of infected i...Predicting the future course of an epidemic depends on being able to estimate the current numbers of infected individuals.However,while back-projection techniques allow reliable estimation of the numbers of infected individuals in the more distant past,they are less reliable in the recent past.We propose two new nonparametric methods to estimate the unobserved numbers of infected individuals in the recent past in an epidemic.The proposed methods are noniterative,easily computed and asymptotically normal with simple variance formulas.Simulations show that the proposed methods are much more robust and accurate than the existing back projection method,especially for the recent past,which is our primary interest.We apply the proposed methods to the 2003 Severe Acute Respiratory Syndorme(SARS) epidemic in Hong Kong.展开更多
文摘The amount of human-caused environmental impact can be evaluated by the degree of pollution. Active coastal marine environmental exploitation has given rise to another problem： marine litter. The period of time allowing to evaluate the change in the degree of the shore pollution with litter is that from 1999 till 2014. Litter can be classified both by qualitative and quantitative character. Regarding qualitative character litter is divided into organic substance （garbage, wood） and non-organic substance （glass, plastics, rubber, metal）. As to the size there are three categories： small, middle, large. As to small litter it is still predominating in the litter structure of the shoreline pollution but its average amount has been decreased significantly. As to the litter distribution, it is mostly concentrated within the beach zone. It is thus natural to assume the land-based origin of the litter, such as litter brought by holiday-makers or introduced by nearby enterprises.
基金supported in part by National Natural Science Foundation of China(Grant Nos. 10771148,11071197)supported by an RGC grant,the Chief Executive Community Project and Hong Kong Jockey Club Charities Trust
文摘Predicting the future course of an epidemic depends on being able to estimate the current numbers of infected individuals.However,while back-projection techniques allow reliable estimation of the numbers of infected individuals in the more distant past,they are less reliable in the recent past.We propose two new nonparametric methods to estimate the unobserved numbers of infected individuals in the recent past in an epidemic.The proposed methods are noniterative,easily computed and asymptotically normal with simple variance formulas.Simulations show that the proposed methods are much more robust and accurate than the existing back projection method,especially for the recent past,which is our primary interest.We apply the proposed methods to the 2003 Severe Acute Respiratory Syndorme(SARS) epidemic in Hong Kong.
