Species richness patterns and the determinants of larch forests in China.

Larch forests are important for species diversity, as well as soil and water conservation in mountain regions. In this study, we determined large-scale patterns of species richness in larch forests and identified the factors that drive these patterns. We found that larch forest species richness was high in southern China and low in northern China, and that patterns of species richness along an elevational gradient depend on larch forest type. In addition, we found that patterns of species richness in larch forests are best explained by contemporary climatic factors. Specifically, mean annual temperature and annual potential evapotranspiration were the most important factors for species richness of tree and shrub layers, while mean temperature of the coldest quarter and anomaly of annual precipitation from the Last Glacial Maximum to the present were the most important for that of herb layer and the whole community. Community structural factors, especially stand density, are also associated with the species richness of larch forests. Our findings that species richness in China's larch forests is mainly affected by energy availability and cold conditions support the ambient energy hypothesis and the freezing tolerance hypothesis.

[Clinical efficacy and safety of akatinol memantine in treatment of mild to moderate Alzheimer disease: a donepezil-controlled, randomized trial].

OBJECTIVE: To evaluate the clinical efficacy and safety of akatinol memantine in the treatment of patients with mild to moderate Alzheimer disease (AD). METHODS: One hundred patients with diagnosis of possible or probable AD and Mini Mental State Examination total scores between 10 and 26 from 6 centers in two cities of China were randomly divided into two groups: akatinol memantine group (n = 50, given akatinol memantine 5 mg/d in first week, 10 mg/d in second week, 15 mg/d in third week and 20 mg/d from fourth to sixteenth week); donepezil group (n = 50, donepezil 5 mg/d). Different scales were used to evaluated cognitive function (MMSE), activity of daily life and behavior and mood (Blessed-Roth scale) as well as the severity of dementia (GDS). Safety evaluation was conducted every 4 weeks. RESULTS: In comparison with the baseline data, there were significant improvements in cognition assessed with MMSE on 16th week in akatinol memantine group (P = 0.000) and donepezil group (P = 0.000) respectively; There also were significant improvements in activity of daily life, behavior and mood assessed by Blessed-Roth scale in akatinol memantine group (P = 0.000) and donepezil group (P = 0.000) on 8th week and 16th week. However there was no improvements in the change of the basic habit of life assessed with the Part II of Blessed-Roth scale (P > 0.05), and nor an improvements in the serious level of dementia assessed with GDS (P > 0.05). In comparison with the data in donepezil group, there were no improvement in the change of MMSE score, Blessed-Roth scale score and GDS score in akatinol memantine group on 16th week (P > 0.05). Mild and transient adverse events were observed in 6% of akatinol memantine group. CONCLUSION: As a safe and effective medicine, akatinol memantine, which has a similar effect as donepezil for AD, can remarkably improve the cognition, behavior, and mood of AD patients.