No abstract

A 1‐year record of hourly atmospheric radon‐222 concentration observations at three ACE‐Asia network sites—Hok Tsui (Hong Kong), Gosan (Jeju Island) and Mauna Loa Observatory (Hawaii)—is presented and discussed. The observations include the spring 2001 ACE‐Asia intensive operation period. Site locations were chosen for the experimental characterization of both boundary layer (Hok Tsui, Gosan) and free tropospheric (Mauna Loa) continental outflow to the Pacific. A significant seasonal variability in background radon concentration is quantified at each site with the ratios of winter maximum to summer minimum background of 96, 15 and 3 for Hok Tsui, Gosan and Mauna Loa, respectively. Only during summer were background radon concentrations directly comparable with unperturbed marine values (∼20 mBq m−3). The variability in radon signal was characterized at each site on diurnal to seasonal timescales. The seasonal variability in fetch regions for air masses experiencing the greatest and smallest terrestrial influence was characterized using 10‐day back trajectories of air masses corresponding to radon concentrations higher (lower) than the 90th (10th) percentile value. The trajectory analyses for Hok Tsui and Gosan, as well as a direct analysis of the experimental results, further supports the previously postulated existence of a strong spatial heterogeneity in the radon source strength in East Asia. Back trajectories of free tropospheric air masses reaching Mauna Loa indicated source regions deep within the Asian continent primarily between 20 and 40°N. This fetch region is different from that influencing the Hok Tsui and Gosan sites. The radon concentration of air masses reaching Mauna Loa was shown to vary seasonally as well as with latitude of the predominant fetch region. Possible mechanisms of this phenomenon have been identified and include (a) seasonal variation in the radon source, (b) seasonal variation in the strength, frequency and/or efficiency of mechanisms that lift boundary layer air to the mid troposphere and (c) seasonal variation in the latitudinal axis of convection.

Herpes simplex virus (HSV) reactivation and lesion formation were studied in 68 renal transplant recipients and 30 leukemic patients. Antibody titers to HSV were determined, and seropositive patients were examined three times weekly for up to one month. Surveillance cultures were taken for oral HSV, and HSV culture and cytology were done for all oral lesions found. In a smaller number of patients, immune responses were determined. HSV reactivation was similar in the transplant and leukemic groups (46.8% vs. 50%), but a significant difference in the incidence of HSV lesion formation was noted between the two groups. Of the transplant patients in whom HSV reactivated, 31.8% developed HSV lesions; of leukemic patients in whom HSV reactivated, 100% developed HSV lesions. Differences in the incidence of formation of HSV lesions in these groups of immunosuppressed patients suggest that reactivation of HSV and formation of HSV lesions may involve different mechanisms. Low levels of antibody-dependent cellular cytotoxicity were noted in leukemic patients and may contribute to increased formation of HSV lesions in this group.

A check-list of endemic vascular plants of the Tian-Shan Mountains, including plant distribution along mountain ranges and in Central Asian countries, has been compiled for the first time in this study. The list of Tian-Shan flora consists of 871 endemic species and subspecies. One subspecies belongs to Pinaceae (Pinopsida) and 870 taxa belong to Magnoliidae (dicots, 732 taxa, and monocots, 138 taxa). The endemic flora belongs to 39 families and 187 genera. The largest number of endemics is concentrated in the mountain ranges of Kyrgyzstan (225 national endemics, 507 taxa in total) and Kazakhstan (205 national endemics, 485 taxa in total). Uzbekistan occupies the third position (69 national endemics, 320 taxa in total). Tajikistan has fewer endemics: 82 taxa, of which only 16 taxa are national endemics. The most represented families and genera are: Asteraceae, Fabaceae, Apiaceae, Lamiaceae, and Amaryllidaceae; and Astragalus, Allium, Cousinia, Oxytropis, and Gagea, respectively.