[Spatial and Temporal Characteristics of Fractional Vegetation Cover and Its Response to Urbanization in Beijing].

Exploration of the spatiotemporal changes in fractional vegetation cover （FVC） and its response characteristics to urbanization is of great significance for urban ecological protection and planning in Beijing. This study analyzed the spatiotemporal characteristics of vegetation cover changes in Beijing from 2000 to 2020 using the Theil-Sen Median and Mann-Kendall methods based on a long-term time series vegetation cover dataset. Then, this study used the urbanization index as a key indicator of spatial urbanization and utilized the transect line and global grid analysis methods to investigate the response characteristics of FVC to different urbanization gradients. The results indicated that： ① FVC changes showed spatial and temporal heterogeneity. From 2000 to 2020, Beijing was predominantly covered by high vegetation, accounting for 65.22% of the total area, which was mainly distributed in ecological conservation areas consistent with the Jundu, Xishan, and Yaji Mountain ranges. The FVC presented an overall positive development trend, with a decreasing trend of areas with low FVC. The increase in FVC was significant （by 28.68%）, mainly distributed in ecological conservation areas and within a range of 10-12 km in concentric circles centered around Tiananmen Square. The urbanization index and FVC change rate were relatively high in Haidian District, Chaoyang District, Fengtai District, Shijingshan District, and Changping District. ② The artificial land surface in 2000, 2010, and 2020 was 9.69%, 13.64%, and 21.19%, respectively, with significant spatial agglomeration and strong spatial heterogeneity. During the urbanization process in Beijing, the increase in artificial land surface reached 11.5%, with the conversion from arable land to artificial land surface accounting for 53.83% of the total land use conversion area. ③ There was a significant negative correlation between FVC and the urbanization index, indicating that urbanization had a negative impact on regional FVC. However, as the urbanization process stabilized, this negative correlation tended to gradually weaken. Although the central urban areas were mainly characterized by low FVC, there was a significant increasing trend in the FVC, indicating a positive development in the FVC and an improvement in regional ecological quality, which was closely related to the governance of the mountain-water-forest-field-lake-grass-sand system. The results of the study can provide a basis for the development of vegetation restoration programs and ecological management measures in Beijing.

[Establishment of an indicator system for comprehensive assessment on terrestrial biodiversity in China]. / ä¸­å›½é™†åŸŸç”Ÿç‰©å¤šæ ·æ€§ç»¼åˆè¯„ä¼°æŒ‡æ ‡ä½“ç³»æž„å»º.

The comprehensive evaluation of terrestrial biodiversity is a key basic work for biodiversity protection. Clarifying the status, trend, and driving factors of biodiversity is premise and necessary for formulating policies and measures of biodiversity protection. At present, there is no unified indicator system for the comprehensive assessment of terrestrial biodiversity in China. We constructed a comprehensive assessment indicator system of terrestrial biodiversity in China, by combining the Aichi biodiversity targets of the Convention on Biological Diversity and the sustainable development goals of the United Nations, learning from the development trend of biodiversity assessment in the world, and following the Pressure-State-Response framework. A total of 22 indicators were obtained, including eight status indicators, seven pressure indicators, and seven response indicators. The correlation and accessibility of the indicators were analyzed. These indicators could be applied to not only an independent assessment for biodiversity status, threatened and protection effectiveness, but also for the comprehensive assessment of terrestrial biodiversity to optimize and adjust priority protection areas and protection measures. Our results would provide a technical support for calculating green GDP and formulating regional ecological compensation policies.

Anti-IFN-γ autoantibodies underlie disseminated Talaromyces marneffei infections.

Talaromyces marneffei causes life-threatening opportunistic infections, mainly in Southeast Asia and South China. T. marneffei mainly infects patients with human immunodeficiency virus (HIV) but also infects individuals without known immunosuppression. Here we investigated the involvement of anti-IFN-γ autoantibodies in severe T. marneffei infections in HIV-negative patients. We enrolled 58 HIV-negative adults with severe T. marneffei infections who were otherwise healthy. We found a high prevalence of neutralizing anti-IFN-γ autoantibodies (94.8%) in this cohort. The presence of anti-IFN-γ autoantibodies was strongly associated with HLA-DRB1*16:02 and -DQB1*05:02 alleles in these patients. We demonstrated that adult-onset acquired immunodeficiency due to autoantibodies against IFN-γ is the major cause of severe T. marneffei infections in HIV-negative patients in regions where this fungus is endemic. The high prevalence of anti-IFN-γ autoantibody-associated HLA class II DRB1*16:02 and DQB1*05:02 alleles may account for severe T. marneffei infections in Southeast Asia. Our findings clarify the pathogenesis of T. marneffei infection and pave the way for developing novel treatments.

Prolonged reversal of long-term potentiation that is N-methyl-D-aspartate receptor independent: implications for memory formation.

Reversal of long-term potentiation (LTP) by low-frequency stimulation (LFS) is often referred to as depotentiation (DP), a phenomenon that is time-dependent. The present study aimed to determine whether LTP could still be reversed when the stimulation was applied beyond the optimal time window in hippocampal slices from adult rats. Field excitatory postsynaptic potentials (fEPSPs) were recorded from the strata radiatum in CA1, following stimulation of Schaffer collaterals. Theta-burst stimulation (TBS) induced LTP that could be reversed by repeated paired-pulse LFS (PP-LFS) after almost 3 h post-TBS. Only when synapse strength reached a plateau did application of PP-LFS trigger DP. In addition, it was surprising to observe that PP-LFS, which generally induces LTD in adult rats, evoked an LTP-like further strengthening in previously potentiationed synapses, even in the presence of APV, a competitive antagonist of N-methyl-D-aspartate receptors (NMDA-Rs). Our results suggest that LTP can be reversed NMDAR-independently more than 2 h after TBS by PP-LFS in adult hippocampus and that saturation of LTP is effective to promote this process.