Modelling seasonal and diurnal dynamics of stomatal conductance of plants in a semiarid environment.

Seasonal and diurnal stomatal conductance, leaf transpiration, and soil water contents of two shrubs of Hippophae rhamnoides L. subsp. Sinensis Rousi and Caragana korshinskii Kom.

[Application of factor analysis in the study of risk factors on human parvovirus B19 infection during pregnancy].

Objective: To explore the risk factors of human parvovirus B19 infection in pregnancy and to provide guidelines for its prevention and control strategy.

Methods: Four hundred and eighty-six cases of gravida serum were detected for parvovirus B19 DNA by nested-polymerase chain reaction assay. Factors associated with parvovirus B19 infection in pregnancy were investigated and analyzed, using multiple logistic regression and factor analysis.

Vegetation uptake of nitrogen and base cations in China and its role in soil acidification.

Vegetation uptake of nitrogen and base cations may be an important source of soil acidity. In this study, the uptake rate of nitrogen and base cations was estimated for each major vegetation type in China. Although the uptake rates of most vegetation types are lower than 2.

[Detection of human parvovirus B19 nonstructural protein DNA by nested- polymerase chain reaction in pregnant women].

Objective: To explore the sensitivity and specificity of the new nested-polymerase chain reaction (nested-PCR) assay in the detection of human parvovirus B19 (HPV B19) nonstructural protein DNA and the applicability of this technique in detecting the gravida infected with parvovirus B19.

Methods: Evaluating the new nested-polymerase chain reaction assay by routine process, and compared with the general nested-PCR in detecting structural protein DNA. Then, the two techniques were used to detect human parvovirus B19 structural protein and nonstructural protein DNA in gravida serum and pregnant tissue of 30 cases.

[Vegetation uptake of nitrogen and base cation in China and its role in soil acidification].

Vegetation uptake of nitrogen and base cation, as well as acid deposition, is an important source of soil acidity. Based on the net primary productivity and elemental composition, the uptake rate of nitrogen and base cation was estimated for each vegetation type in China. Result showed that the uptake rate of nitrogen was commonly low in southeast China and high in northwest China, and decreased gradually from southeast to northwest in northwest China.