High prevalence of HIV-1 and hepatitis C virus coinfection among injection drug users in the southeastern region of Yunnan, China

The southeastern region of Yunnan province is a key site for drug trafficking and HIV-1 infection spread from the west of Yunnan and Laos to southeastern China. To investigate the prevalence of HIV-1 infection and hepatitis C virus (HCV) coinfection among injection drug users (IDUs) in southeastern Yunnan, three cohorts of 285 addicts, including 242 IDUs and 43 oral drug users, living in the cities of Gejiu and Kaiyuan and the county of Yanshan were studied. HIV-1 and HCV infections were detected by enzyme-linked immunosorbent assay and/or polymerase chain reaction. Data on the age, sex, risk behavior, drug use history, employment, ethnic background, and marriage status were obtained by interview. The overall prevalence of HIV-1 infection was 71.9%. The rate of HCV coinfection among 138 HIV-1-infected IDUs was 99.3%. Most HIV-infected IDUs were 20 to 35 years old (86.7%) and were ethnic Han (75.9%), suggesting that the epidemic in Yunnan is no longer confined to non-Han ethnic minorities, HIV prevalence in female IDUs (81.2%) was significantly higher than in male IDUs (68.2%) (p <.05). The prevalence of HIV infection reached 68.4% after 1 year of injection drug use. Needle/syringe sharing is the major high risk factor for the spread of HIV-1 and HCV infections. Large-scale educational campaigns are urgently needed to reduce the spread of HIV and HCV infection in these regions.

A shortest path algorithm for moving objects in spatial network databases

One of the most important kinds of queries in Spatial Network Databases (SNDB) to support location-based services (LBS) is the shortest path query. Given an object in a network, e.g. a location of a car on a road network, and a set of objects of interests, e.g. hotels,gas station, and car, the shortest path query returns the shortest path from the query object to interested objects. The studies of shortest path query have two kinds of ways, online processing and preprocessing. The studies of preprocessing suppose that the interest objects are static. This paper proposes a shortest path algorithm with a set of index structures to support the situation of moving objects. This algorithm can transform a dynamic problem to a static problem. In this paper we focus on road networks. However, our algorithms do not use any domain specific information, and therefore can be applied to any network. This algorithm’s complexity is O(klog2 i), and traditional Dijkstra’s complexity is O((i + k)2).

a shortest path algorithm for moving objects in spatial network databases

中国计算机学会