Long-term ecological restoration increased plant diversity and soil total phosphorus content of the alpine flowing sand land in northwest Sichuan, China.

The ecological restoration techniques that combine grazing, sand barriers with willows, fertilization, artificial planting, and continuous management are increasingly adopted in the management of flowing sandy land in high-altitude and cold regions. However, few studies have focused on the long-term ecological restoration effects of such technologies. This study systematically compared the vegetation and soil characteristics under different ecological restoration durations (0 (CK), 3 (F1), 14 (F2), 26 (F3), and 46 (F4) years) in the alpine sandy land of northwest Sichuan. The results showed that, with the increase of ecological restoration durations, (1) the aboveground and underground biomass of plants, and species number significantly increased, while the shannon-wiener index, margalef index, and simpson index dramatically decreased; (2) in the early stage of ecological restoration (0-3 yr), Cyperaceae accounted for the main groups, while in the late stage of ecological restoration (14-46 yr), Leguminosae and Forb groups predominated; (3) ecological restoration durations significantly influenced the total phosphorus (TP) content at a soil depth of 0-60 cm, but soil organic carbon and C/P ratio were only significantly impacted at 40-60 cm; (4) the plant and soil characteristics of F1, F2, and F3 treatments were more similar, and CK and F4 treatments were clearly distinguished on PC1 of principal component analysis; (5) there was no significant correlation between Leguminosae groups and environmental factors. Instead, a correlation between total nitrogen (TN) and Forb groups, Gramineae groups, and Cyperaceae groups was revealed. TN was very significantly positively correlated with species diversity and TP. Long-term ecological restoration improved plants biomass, plant species diversity, functional plant groups, and increased soil TP content in the alpine sandy land of northwest Sichuan.

Drought characteristics and dominant factors across China: Insights from high-resolution daily SPEI dataset between 1979 and 2018.

Drought, a complex phenomenon exacerbated by climate change, is influenced by various climate factors. The escalating global temperatures associated with climate change, impact precipitation patterns and water cycle processes, consequently intensifying the occurrence and severity of droughts. To effectively address and adapt to these challenges, it is crucial to identify the dominant climate factors driving drought events. In this study, we utilized the 1979-2018 Chinese meteorological forcing dataset to calculate the daily Standardized Precipitation Evapotranspiration Index (SPEI). The Theil-Sen and Mann-Kendall (M-K) tests were employed to analyze the spatial and temporal trends of drought severity and duration. Additionally, partial correlation analysis was conducted to examine the relationship between climate factors (precipitation and potential evapotranspiration (PET)) and drought characteristic (drought severity and duration). Through this comprehensive analysis, we aimed to identify the primary factors influencing drought severity and duration. The findings revealed the following key results: (1) Over the 40-year period from 1979 to 2018, drought trends in China and its seven climate divisions exhibited an increasing pattern. (2) During drought periods, most regions exhibited a positive correlation between PET and drought severity and duration, while precipitation demonstrated a negative correlation. However, certain areas experiencing severe drought displayed a negative correlation between PET and drought severity and duration, precipitation demonstrated a positive correlation with drought severity and duration. (3) PET emerged as the dominant climatic factor for meteorological drought in the majority of China. These findings contribute valuable insights for policymakers in the development of climate change adaptation and mitigation strategies. By understanding the dominant climate factors driving drought events, policymakers can implement effective measures to mitigate the adverse socioeconomic and environmental impacts associated with climate change.

An improved global vegetation health index dataset in detecting vegetation drought.

Due to global warming, drought events have become more frequent, which resulted in aggravated crop failures, food shortage, larger and more energetic wildfires, and have seriously affected socio-economic development and agricultural production. In this study, a global long-term (1981-2021), high-resolution (4 km) improved vegetation health index (VHI) dataset integrating climate, vegetation and soil moisture was developed. Based on drought records from the Emergency Event Database, we compared the detection efficiency of the VHI before and after its improvement in the occurrence and scope of observed drought events. The global drought detection efficiency of the improved high-resolution VHI dataset reached values as high as 85%, which is 14% higher than the original VHI dataset. The improved VHI dataset was also more sensitive to mild droughts and more accurate regarding the extent of droughts. This improved dataset can play an important role in long-term drought monitoring but also has the potential to assess the impact of drought on the agricultural, forestry, ecological and environmental sectors.

The development and future frontiers of global ecological restoration projects in the twenty-first century: a systematic review based on scientometrics.

Ecological restoration projects are becoming a mainstream of research, and their studies are widely followed by scholars worldwide, yet there is no comprehensive review of this research. Nowadays, bibliometrics has attracted much attention from the scientific community, and its methodological approach allows quantitative and qualitative analysis of research performance in journals or subject areas. This paper provides a systematic and comprehensive description of the progress and hotspots of ecological restoration projects from a bibliometric perspective, based on 1173 articles in the Web of Science Core Collection (WOSCC) database. Research on ecological restoration projects has shown a positive growth trend since the twenty-first century. China and the USA are the most active countries in terms of the number of relevant articles published, and more than half of the top 10 active institutions are from China, but there is less collaboration between different countries/institutions. Research in ecological restoration projects is summarized into three main research areas: the main ecological damage problems, the impact of human beings on ecological damage, and the main methods of ecological restoration. Finally, some challenges and outlooks conducive to the rapid and balanced development of ecological restoration projects are presented, which provide valuable references and help for future researchers.

Some Thoughts on the Use of Predictive Probability in Clinical Trials.

In this short note, we express our viewpoint regarding declaring study success based on Bayesian predictive probability of study success.

Recurrence analysis of extreme historical drought under the current defense conditions in China.

Quantifying historical extreme drought is crucial to better understand and contextualize historical extreme droughts and prepare for extreme drought events that may occur in the future. However, the potential impacts of extreme droughts such as those in historical records considering modern day drought resistance and mitigation capacities remain unclear. In order to present the methods of reconstructing historical drought recurrence and conduct a historical drought recurrence scenario analysis under the current defense conditions, a modern day recurrence of the Guangxu drought during the Qing Dynasty from 1875 to 1879 was proposed using the Qing Palace Archives. In which, the historical annual precipitation in core drought areas was quantitatively reconstructed based on snow-rain records derived from the Qing Dynasty archives. And the extreme Guangxu drought was analyzed by establishing the corresponding relationship between precipitation anomaly percentage and the historical drought catalog. This allowed for the characterization of possible impacts of severe drought on water resources, water supply, food production, and economy under current defense conditions. The results showed that if the Guangxu drought occurred today under the current natural geographical conditions, core drought areas like Beijing, Tianjin, Hebei, Shanxi, Shaanxi, Henan, and Shandong would experience water shortages greater than 50% of their multi-year average water resources. In addition, we found that water transfer projects and large-medium-sized reservoirs will play central roles in drought mitigation in the event of an historical extreme drought.

TGF-ß1-induced chondrogenesis of bone marrow mesenchymal stem cells is promoted by low-intensity pulsed ultrasound through the integrin-mTOR signaling pathway.

BACKGROUND: Low-intensity pulsed ultrasound (LIPUS) is a mechanical stimulus that plays a key role in regulating the differentiation of bone marrow mesenchymal stem cells (BMSCs). However, the way in which it affects the chondrogenic differentiation of BMSCs remains unknown. In this study, we aimed to investigate whether LIPUS is able to influence TGF-ß1-induced chondrogenesis of BMSCs through the integrin-mechanistic target of the Rapamycin (mTOR) signaling pathway. METHODS: BMSCs were isolated from rat bone marrow and cultured in either standard or TGF-ß1-treated culture medium. BMSCs were then subjected to LIPUS at a frequency of 3 MHz and a duty cycle of 20%, and integrin and mTOR inhibitors added in order to analyze their influence on cell differentiation. BMSCs were phenotypically analyzed by flow cytometry and the degree of chondrogenesis evaluated through toluidine blue staining, immunofluorescence, and immunocytochemistry. Furthermore, expression of COL2, aggrecan, SOX9, and COL1 was assessed by qRT-PCR and western blot analysis. RESULTS: We found that LIPUS promoted TGF-ß1-induced chondrogenesis of BMSCs, represented by increased expression of COL2, aggrecan and SOX9 genes, and decreased expression of COL1. Notably, these effects were prevented following addition of integrin and mTOR inhibitors. CONCLUSIONS: Taken together, these results indicate that mechanical stimulation combined with LIPUS promotes TGF-ß1-induced chondrogenesis of BMSCs through the integrin-mTOR signaling pathway.

Modeling of correlated data with informative cluster sizes: An evaluation of joint modeling and within-cluster resampling approaches.

Joint modeling and within-cluster resampling are two approaches that are used for analyzing correlated data with informative cluster sizes. Motivated by a developmental toxicity study, we examined the performances and validity of these two approaches in testing covariate effects in generalized linear mixed-effects models. We show that the joint modeling approach is robust to the misspecification of cluster size models in terms of Type I and Type II errors when the corresponding covariates are not included in the random effects structure; otherwise, statistical tests may be affected. We also evaluate the performance of the within-cluster resampling procedure and thoroughly investigate the validity of it in modeling correlated data with informative cluster sizes. We show that within-cluster resampling is a valid alternative to joint modeling for cluster-specific covariates, but it is invalid for time-dependent covariates. The two methods are applied to a developmental toxicity study that investigated the effect of exposure to diethylene glycol dimethyl ether.

Use of auxiliary covariates in estimating a biomarker-adjusted treatment effect model with clinical trial data.

A biomarker-adjusted treatment effect (BATE) model describes the effect of one treatment versus another on a subpopulation of patients defined by a biomarker. Such a model can be estimated from clinical trial data without relying on additional modeling assumptions, and the estimator can be made more efficient by incorporating information on the main effect of the biomarker on the outcome of interest. Motivated by an HIV trial known as THRIVE, we consider the use of auxiliary covariates, which are usually available in clinical trials and have been used in overall treatment comparisons, in estimating a BATE model. Such covariates can be incorporated using an existing augmentation technique. For a specific type of estimating functions for difference-based BATE models, the optimal augmentation depends only on the joint main effects of marker and covariates. For a ratio-based BATE model, this result holds in special cases but not in general; however, simulation results suggest that the augmentation based on the joint main effects of marker and covariates is virtually equivalent to the theoretically optimal augmentation, especially when the augmentation terms are estimated from data. Application of these methods and results to the THRIVE data yields new insights on the utility of baseline CD4 cell count and viral load as predictive or treatment selection markers.