Challenges for sustainable development goal of land degradation neutrality in drylands: Evidence from the Northern Slope of the Tianshan Mountains, China.

The SDG 15.3.1 target of Land Degradation Neutrality (LDN) only has 15 years from conception (in 2015) to realization (in 2030). Therefore, investigating the effectiveness and challenges of LDN has become a priority, especially in drylands, where fragile ecosystems intersect with multiple disturbances. In this study, solutions are proposed and validated based on the challenges of LDN. We chose the Northern Slope of the Tianshan Mountains as a case study and set baselines in 2005 and 2010. The region and degree of land change (including degraded, stable, and improved) were depicted at the pixel scale (100 × 100 m), and LDN realization was assessed at the regional scale (including administrative districts and 5000 × 5000 m grids). The results showed a significant disparity between the two baselines. The number of areas that realized the LDN target was rare, regardless of the scale of the administrative districts or grids. Chord plots, Spearman's correlation, and curve estimation were employed to reveal the relationship between LDN and seven natural or socioeconomic factors. We found that substantial degradation was closely related to the expansion of unused, urban, and mining land and reduction in water, glaciers, and forests. Further evidence suggests that agricultural development both positively and negatively affects LDN, whereas urbanization and mining activities are undesirable for LDN. Notably, the adverse effects of glacier melting require additional attention. Therefore, we consider the easy-to-achieve and hard-to-achieve baselines as the mandatory and desirable targets of LDN, respectively, and focus further efforts in three aspects: preventing agricultural exploitation from occupying ecological resources, defining reasonable zones for urbanization and mining, and reducing greenhouse gas emissions to mitigate warming. Overall, this study is expected to be a beneficial addition to existing LDN theoretical systems and serve as a case validation of the challenges of LDN in drylands.

Synthesis of α-Trifluoromethyl Alkynes through Fluoroalkynylation of gem-Difluoroalkenes.

A trifluoromethylalkynylation reaction of gem-difluoroalkenes with alkynyl sulfoxide by photoredox radical addition with good functional group tolerance in moderate to high yields, is developed for the synthesis of α-trifluoromethyl alkyne. This reaction features simple operation and inexpensive raw materials and provides an expeditious route to synthesize biologically relevant fluorine-containing alkynyl compounds with diverse structural skeletons.

Copper-Catalyzed Monofluoroalkylation of Allyl Phosphates with Nucleophilic Ethyl 2-Fluoro-2-(trimethylsilyl)acetate.

An efficient method for C(sp3)-CHF bond formation was successfully developed by copper-catalyzed cross-coupling of allyl phosphate with 2-fluoro-2-(trimethylsilyl)acetate. Under moderate circumstances, the conversion was carried out in a good strategic range to provide a series of monofluoroalkylation products in high yields, which also demonstrates the practicality of gram-scale reactions.

A Comprehensive Evaluation Framework of Water-Energy-Food System Coupling Coordination in the Yellow River Basin, China.

For mankind's survival and development, water, energy, and food (WEF) are essential material guarantees. In China, however, the spatial distribution of WEF is seriously unbalanced and mismatched. Here, a collaborative governance mechanism that aims at nexus security needs to be urgently established. In this paper, the Yellow River Basin in China with a representative WEF system, was selected as a case. Firstly, a comprehensive framework for WEF coupling coordination was constructed, and the relationship and mechanism between them were analyzed theoretically. Then, we investigated the spatiotemporal characteristics and driving mechanisms of the coupling coordination degree (CCD) with a composite evaluation method, coupling coordination degree model, spatial statistical analysis, and multiscale geographic weighted regression. Finally, policy implications were discussed to promote the coordinated development of the WEF system. The results showed that: 1) WEF subsystems showed a significant imbalance of spatial pattern and diversity in temporal changes; 2) the CCD for the WEF system varied little and remained at moderate coordination. Areas with moderate coordination have increased, while areas with superior coordination and mild disorder have decreased. In addition, the spatial clustering phenomenon of the CCD was significant and showed obvious characteristics of polarization; and 3) the action of each factor is self-differentiated and regionally variable. For different factors, GDP per capita was of particular importance, which contributed most to the regional development's coupling coordination. For different regions, GDP per capita, average yearly precipitation, population density, and urbanization rate exhibited differences in geographical gradients in an east-west direction. The conclusion can provide references for regional resource allocation and sustainable development by enhancing WEF system utilization efficiency.