Periodicities in the occurrence of aurora as indicators of solar variability

A compilation of records of the aurora observed in China from the Time of the Legends (2000 - 3000 B.C.) to the mid-18th century has been used to infer the frequencies and strengths of solar activity prior to modern times. A merging of this analysis with auroral and solar activity patterns during the last 200 years provides basically continuous information about solar activity during the last 2000 years. The results show periodicities in solar activity that contain average components with a long period (approx. 412 years), three middle periods (approx. 38 years, approx. 77 years, and approx. 130 years), and the well known short period (approx. 11 years)

Disease control and prevention in China in the 20th century and prospects for the new millennium

In the first part of the paper, the main achievements and experience of disease control and prevention in China during last 50 years are described. Infectious diseases and parasitosis have been successfully controlled and prevented and people’s health enhanced owing to the establishment of an effective system of public health, the launch of a campaign called “Patriotic Public Health”, immunization planning, and the improvement of economic and environmental conditions. In the second part, the challenges to public health in China are presented. The threat from old and emerging infectious diseases, especially sexually transmitted diseases, a sustained increase in the prevalence of chronic non-infectious diseases (cardiovascular diseases tumors and diseases of the respiratory system), environmental problems and the health problems of aging are discussed. Finally, strategies for disease control and prevention in the new century is suggested