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Global grassland degradation has prompted professionals and practitioners to critically consider about the future of grassland resources. Restoration actions related to payment for ecosystem services (PES) have been proposed as a possible approach to balancing grassland sustainable development and ecosystem service supply. Since 2005, approximately one billion U.S. dollars have been invested in the Three-River Headwater Region (TRHR) of China to restore 5.69 × 106 ha of degraded grasslands via grassland cultivation and fencing. Unfortunately, few literature has drawn valid and generalizable conclusions regarding the economic performance of these PES programs. Therefore, field data from multiple sites were collected to evaluate the economic returns of restoration actions, returns on investments (ROI), and trade-offs among ecosystem services of cultivated and fenced grasslands over different restoration years in the TRHR. The results revealed that PES-related restoration efforts in the TRHR had yielded a net profit of $14.34 billion, with $13.20 billion from the alpine meadow, $0.74 billion from the alpine steppe and $0.40 billion from the temperate steppe. These substantial economic can be attributed to the combined effects of the surge in specific ecosystem services and the synergistic improvement of all ecosystem services. The ROI of supporting service accounted for the largest proportion of ROI in total ecosystem services and exhibited drastic fluctuations with restoration years, whereas the ROI of other services either increased gradually or remained stable across different restoration periods. The trade-offs in ecosystem services varied greatly with grassland type. We observed an increasing synchronization of ecosystem services over time in the fenced alpine steppe, cultivated alpine meadow, and cultivated temperate steppe; whereas a similar trend was not detected in other grasslands. Our research underscores the importance of incorporating herders' willingness, assessing restoration performance of grasslands and adopting more targeted and adaptive restoration actions in subsequent PES programs. • PES helped balance sustainable development and ecosystem conservation. • Multiple site data was collected to explore ecological returns of restoration actions. • Restoration actions with PES programs had yielded a net profit of $14.34 billion. • Gains were owed to surge of specific ecosystem services and synergy of all services. • Herders' willingness and more targeted actions should be considered in next steps. [ABSTRACT FROM AUTHOR]

The spectral characterization of flow-field parameters provides a new perspective for understanding the spatiotemporal evolution of unsteady supersonic exhaust plumes and for extracting typical structures. In this study, a large-eddy simulation is performed to calculate the three-dimensional unsteady supersonic plume flow field of rocket engines, and a spectral proper orthogonal decomposition (SPOD) method with a spatiotemporal separation is established. This approach is used to extract the coherent structural features of the unsteady exhaust plume flow field and analyze the mode space structure at different frequencies. The three-dimensional reconstruction and denoising of the exhaust plume flow-field parameters can be achieved via the frequency- and time-domain reconstructions of the SPOD algorithm and oblique projection method, respectively. The ground rocket exhaust plume of ballistic evaluation motor-II is analyzed. The results indicate that the SPOD method can effectively extract the single-frequency mode structure of the reactive supersonic flow field, and that low-order behavior appears in the m = 0 and m = 1 azimuth modes. The potential core exhibits a high-frequency wave-packet structure that is affected by shock waves and shear layers. Time-domain reconstruction based on the oblique projection method facilitates the capture of the dynamic characteristics of the flow field. For the first-order SPOD mode, the frequency- and time-domain reconstruction errors are 3.3% and 1.5%, respectively. The frequency-domain reconstruction method exhibits a 4% improvement in denoising ability compared to low-pass filters. This study provides a novel method for the spectral characterization and spatiotemporal feature extraction of supersonic exhaust plume flow fields. [ABSTRACT FROM AUTHOR]

How climate change and human activities drive the evolution of the regional environment and where the quality of ecosystems improve or decline over time have become widespread concerns. In this study, we took the Three-River-Source (TRS) region of the Qinghai–Tibet Plateau as a case, aiming to identify and quantify the contribution of the natural and anthropogenic factors to the ecosystem changes over the past years from 1980 to 2018 using the methods of remote sensing and spatial statistical analysis. Based on the land cover map interpreted by reference to satellite remote sensing imagery data, we defined the Ecological Restoration Area Proportion (ERAP) as the bare land patch decrement to indicate the ecologically restored quantity in space. Assembling the restoration project information, we digitalized and vectorized the ecological Restoration Intensity (RI) including the spatial range and temporal duration. Combining the ERAP and the net primary productivity (NPP), which indicates the quantity and quality of ecosystems, respectively, the ecological asset Index (EAI) was developed and calculated. Having integrated the datasets of the vegetation monitoring, climatic factors, geographical factors, and human activities, we performed multi-variable analysis of the attribution of how the change in the EAI, the NPP, and the EAI have been affected by these factors together. The NPP of the middle and eastern parts of the TRS region has improved the most, as the average growth rate of NPP reached approximately 2.5 kg C/m2/10a. Due to such dynamic pattern, we found that human-induced re-vegetation has made limited contributions in our multi-regression model as the variance explained by the RI merely amounts to 4.4% to 8.8%, while the changes were mostly dependent on the regional temperature and the precipitation which contributed over 45% to the ecological restoration on average. It was summarized that "climate-help" overwhelms "human act" in such alpine grassland ecosystem. The regression results for the different aspects of the ERAP and NPP demonstrated that the ecological restoration project helped most in regard to ecosystem quality improvement rather than the restored ecosystem quantity. Our study has developed a comprehensive assessment methodology that can be reused to account for more ecological asset. The case is an example of an alpine ecosystem in which the success of ecological restoration needs favorable climatic conditions as supporting evidence for the nature-based solution. [ABSTRACT FROM AUTHOR]

Background: An anterior cruciate ligament (ACL) injury accompanied by patellar instability (PI) is a topic that has gained orthopaedic surgeons' attention recently. Untreated PI is reportedly associated with worse clinical outcomes after isolated ACL reconstruction (ACLR) in patients after an ACL injury with PI. Nevertheless, the appropriate surgical approach and its long-term therapeutic effects in these patients remain unclear. Purpose: (1) To compare the clinical and radiological outcomes between isolated ACLR (iACLR) and combined ACLR and medial patellofemoral ligament reconstruction (cAMR) in patients after an ACL injury with PI and (2) to explore the correlations between these 2 procedures and clinical and radiological outcomes. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 106 patients diagnosed with an ACL injury accompanied by PI between January 2016 and April 2021 were analyzed in this study. There were 34 patients excluded because of missing postoperative radiological data. Among the remaining 72 patients, 34 patients underwent iACLR, while 38 patients underwent cAMR. Demographic characteristics, intraoperative findings, and patient-reported outcomes (Lysholm score, subjective International Knee Documentation Committee score, and Tegner activity score) were prospectively collected. Patellar alignment parameters and worsening patellofemoral osteoarthritis (PFOA) features (evaluated with the modified Whole-Organ Magnetic Resonance Imaging Score) were analyzed longitudinally on magnetic resonance imaging. The Kujala score was used to evaluate the functional recovery of the patellofemoral joint, and redislocations of the patella were prospectively recorded. Finally, multivariate logistic regression analysis was used to explore the correlations between these 2 procedures and clinical (not achieving the minimal detectable change [MDC] for the Lysholm score) and radiological (worsening PFOA features) outcomes. Results: The mean follow-up duration was 28.9 ± 6.2 and 27.1 ± 6.8 months for the iACLR and cAMR groups, respectively (P =.231). Significantly higher Lysholm scores (88.3 ± 9.9 vs 82.1 ± 11.1, respectively; P =.016) and subjective International Knee Documentation Committee scores (83.6 ± 11.9 vs 78.3 ± 10.2, respectively; P =.046) were detected in the cAMR group compared with the iACLR group postoperatively. The rates of return to preinjury sports were 20.6% and 44.7% in the iACLR and cAMR groups, respectively (difference, 24.1% [95% CI, 3.3%-45.0%]; P =.030). Moreover, the rates of worsening PFOA features were 44.1% and 18.4% in the iACLR and cAMR groups, respectively (difference, 25.7% [95% CI, 4.9%-46.4%]; P =.018). In addition, significantly higher Kujala scores (87.9 ± 11.3 vs 80.1 ± 12.0, respectively; P =.006), lower redislocation rates (0.0% vs 11.8%, respectively; difference, 11.8% [95% CI, 0.9%-22.6%]; P =.045), and significantly better patellar alignment were detected in the cAMR group compared with the iACLR group postoperatively. Furthermore, multivariate logistic regression analysis determined that iACLR and partial lateral meniscectomy were significantly correlated with not achieving the MDC for the Lysholm score and worsening PFOA features in our study population. Conclusion: In patients after an ACL injury with PI, cAMR yielded better clinical and radiological outcomes compared with iACLR, with better patellar stability and a lower proportion of worsening PFOA features. Furthermore, not achieving the MDC for the Lysholm score and worsening PFOA features were significantly correlated with iACLR and partial lateral meniscectomy. Our study suggests that cAMR may be a more appropriate procedure for patients after an ACL injury with PI, which warrants further high-level clinical evidence. [ABSTRACT FROM AUTHOR]

• Developed Semi-analytic Monte Carlo Method for solid rocket plume polarized radiation. • Simulated solid rocket plume polarized characteristics. • The effects of different light sources on the polarized characteristics of the plume were analyzed. Polarization optical detection has been widely used in the detection and identification of particle containing media such as clouds, aerosols, fire plumes, and volcanic smoke. Solid rocket plume is a typical high-temperature gas–solid two-phase medium. Polarization optical detection of solid rocket plume has attracted much attention in recent years. The polarized radiation transfer mechanism of solid rocket plume is complex, especially in the infrared band, with both the scattering radiation transfer from external incident light and the scattering radiation transfer from the high-temperature region inside the jet flame to the outside. The research on the polarization scattering characteristics of solid jet flame still needs to be further developed. Therefore, this study focuses on modeling the infrared polarization scattering mechanism and the simulation of polarization transfer characteristics of a solid rocket gas–solid two-phase plume, which can guide the usability analysis of solid rocket plume polarization detection. A novel model based on Semi-analytic Monte Carlo Method is proposed to simulate polarized radiation transfer of solid rocket plume. The wavelength and angle dependence of the self-radiation polarization characteristic of a solid rocket plume is simulated based on the proposed model. Note that the overall polarization degree of the plume shows wavelength selectivity and angle sensitivity at different wavelengths. The spatial distribution of polarization degree at 1.55 μm, 2.2 μm, and 2.75 μm shows that the plume edge's polarization degree is higher than the plume center. The findings suggest that the ratios of the relative contribution of self-radiation, direct solar radiation, and background polarization radiation components to the total polarization characteristics are 0.47 %, 70.50 %, 29.03 % at 1.55 μm and 20.43 %, 79.55 %, 0.02 % at 2.75 μm. [ABSTRACT FROM AUTHOR]

• It was found that the agricultural land expanded significantly, desert reduced from 1993 to 2019 in the oasis region in Hotan River Basin, China. • The key indicators of the coupling system of vegetation–climate, soil-adjusted vegetation index, albedo, surface temperature, and evapotranspiration were calculated and mapped their spatial-temporal dynamics. • We investigated how the different landscape patterns altered the interaction between vegetation and climate in the desert oasis ecosystem and quantified the effects with structural equation model. In the arid region, the oasis is characterized by a desert substance and a mosaic of vegetation. The biophysical processes and interactions between vegetation and the local climate in this kind of region are determined by the macroscopic structure of the ecosystems, i.e. landscape patterns. To understand how these landscape patterns impact regional hydro-heat coupling across space and evolve over time, we utilized remote sensing observational data and methods to examine the relationships among these factors. In this case, we focused on the oasis along the upstream of the Hotan River Basin in the Taklamakan Desert in Xinjiang of western China and employed the satellite imagery datasets of Landsat from 1993 to 2019 to investigate the dynamics of vegetation–climate factors. Based on the land use and cover change datasets, the landscape pattern metrics, including patch density (PD), contagion index (CONTAG), fractal dimension (FRAC), were calculated to measure the landscape features on the different aspects, i.e. the fragmentation, the connectivity, and the complexity. With the algorithm of land surface energy balance, the land surface indicators, including the soil-adjusted vegetation index (SAV I), albedo, surface irradiance temperature (T s), and evapotranspiration (ET), were calculated to represent the key process in the interaction of vegetation–climate. The temporal-spatial dynamics of the landscape patterns and the vegetation–climate metrics were mapped and demonstrated in a quantitative manner. The statistical results revealed that during the past decades, the agricultural land in the study area had significantly increased by 17 %. Grassland and shrubs had also expanded, while the desert area decreased from 82.57 % to 78.82 % of the total area, with an overall reduction rate of 1.4 %/10a. It was found the study area was getting warmer and dryer based on the general trends of T s and ET observed during the period of 1993–2019. The agricultural land had the highest PD and CONTAG , and the lowest FRAC. The agricultural land had the lowest T s and the highest ET. The results of structural equation model identified the decoupling effects of PD and CONTAG on the regional hydro-heat environment, while confirmed that FRAC had positive impact on the coupling between T s and ET. Our study bridged the landscape pattern with the regional vegetation–climate interaction and provided the suggestions for the landscape planning and management for a more sustainable arid region. [Display omitted] [ABSTRACT FROM AUTHOR]