Land surface evapotranspiration (ET) is a central component of the Earth's global energy balance and water cycle. Understanding ET is important in quantifying the impacts of human influences on the ...hydrological cycle and thus helps improving water use efficiency and strengthening water use planning and watershed management. China has experienced tremendous land use and land cover changes (LUCC) as a result of urbanization and ecological restoration under a broad background of climate change. This study used MODIS data products to analyze how LUCC and climate change affected ET in China in the period 2001–2013. We examined the separate contribution to the estimated ET changes by combining LUCC and climate data. Results showed that the average annual ET in China decreased at a rate of −0.6mm/yr from 2001 to 2013. Areas in which ET decreased significantly were mainly distributed in the northwest China, the central of southwest China, and most regions of south central and east China. The trends of four climatic factors including air temperature, wind speed, sunshine duration, and relative humidity were determined, while the contributions of these four factors to ET were quantified by combining the ET and climate datasets. Among the four climatic factors, sunshine duration and wind speed had the greatest influence on ET. LUCC data from 2001 to 2013 showed that forests, grasslands and croplands in China mutually replaced each other. The reduction of forests had much greater effects on ET than change by other land cover types. Finally, through quantitative separation of the distinct effects of climate change and LUCC on ET, we conclude that climate change was the more significant than LULC change in influencing ET in China during the period 2001–2013. Effective water resource management and vegetation-based ecological restoration efforts in China must consider the effects of climate change on ET and water availability.
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•Individual effects of climate change and LUCC on ET in China were quantified.•Effect of climate change on ET was much more significant than effect of LUCC.•Deforestation had a greater influence on ET relative to afforestation.•Sunshine duration was the dominant climatic factor for ET changes in China.
Urban heat island (UHI) is one major anthropogenic modification to the Earth system that transcends its physical boundary. Using MODIS data from 2003 to 2012, we showed that the UHI effect decayed ...exponentially toward rural areas for majority of the 32 Chinese cities. We found an obvious urban/rural temperature "cliff", and estimated that the footprint of UHI effect (FP, including urban area) was 2.3 and 3.9 times of urban size for the day and night, respectively, with large spatiotemporal heterogeneities. We further revealed that ignoring the FP may underestimate the UHI intensity in most cases and even alter the direction of UHI estimates for few cities. Our results provide new insights to the characteristics of UHI effect and emphasize the necessity of considering city- and time-specific FP when assessing the urbanization effects on local climate.
Accurately monitoring global vegetation dynamics with modern remote sensing is critical for understanding the functions and processes of the biosphere and its interactions with the planetary climate. ...The MODerate resolution Imaging Spectroradiometer (MODIS) vegetation index (VI) product has been a primary data source for this purpose. To date, the MODIS team had released several versions of VI products that have widely used in global change studies and practical applications. In this study, we re-examined the global vegetation activity by comparing the recent MODIS Collection 6 (C6) VIs with Collection 5 (C5) VIs including Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) from Terra (2001–2015) and Aqua Satellites (2003–2015). We found substantial differences in global vegetation trends betweenTerra-C5 and -C6 VIs, especially EVI. From 2001 to 2015, global vegetation showed a remarkable greening trend in annual EVI from the Terra-C6 (0.28% year−1; P<0.001), in contrast to the decreasing EVI trend from the Terra-C5 (−0.14% year−1, P<0.01). Spatially, large portions of the browning areas in tropical regions identified by Terra-C5 VIs were not evident in Terra-C6 VIs. In contrast, the widespread greening areas in Terra-C6 VIs were consistent with Aqua-C6 VIs and GIMMS3g NDVI. Our finding of a greening Earth supports the recent studies suggesting an enhanced land carbon sink. Our study suggests that most of the vegetation browning trends detected by MODIS Terra-C5 VIs were likely caused by sensor degradation, particularly for the period after 2007. Therefore, previous studies of temporal vegetation trends based solely on Terra-C5 VIs may need to be reevaluated. Our new analysis offers the most updated understanding of the global vegetation dynamics during the past 15years and contributes to accurately understanding the role of vegetation played in the Earth's biogeochemical and climatic systems.
•A significant greening Earth was detected by MODIS Terra-C6 VIs.•The widespread browning areas in Terra-C5 VIs were likely artifacts of sensor degradation.•A greening Earth is consistent with the enhanced land carbon sink suggested by recent studies.
The world's largest afforestation programs implemented by China made a great contribution to the global “greening up.” These programs have received worldwide attention due to its contribution toward ...achieving the United Nations Sustainable Development Goals. However, emerging studies have suggested that these campaigns, when not properly implemented, resulted in unintended ecological and water security concerns at the regional scale. While mounting evidence shows that afforestation causes substantial reduction in water yield at the watershed scale, process‐based studies on how forest plantations alter the partitioning of rainwater and affect water balance components in natural vegetation are still lacking at the plot scale. This lack of science‐based data prevents a comprehensive understanding of forest‐related ecosystem services such as soil conservation and water supply under climate change. The present study represents the first “Paired Plot” study of the water balance of afforestation on the Loess Plateau. We investigate the effects of forest structure and environmental factors on the full water cycle in a typical multilayer plantation forest composed of black locust, one of the most popular tree species for plantations worldwide. We measure the ecohydrological components of a black locust versus natural grassland on adjacent sites. The startling finding of this study is that, contrary to the general belief, the understory—instead of the overstory—was the main water consumer in this plantation. Moreover, there is a strict physiological regulation of forest transpiration. In contrast to grassland, annual seepage under the forest was minor in years with an average rainfall. We conclude that global long‐term greening efforts in drylands require careful ecohydrologic evaluation so that green and blue water trade‐offs are properly addressed. This is especially important for reforestation‐based watershed land management, that aims at carbon sequestration in mitigating climate change while maintaining regional water security, to be effective on a large scale.
A process‐based “Paired plot” study suggests that conversion of croplands to forests and grasslands in a dryland region resulted in a complex change of precipitation partitioning between green and blue flows. Forest plantations use more water than grasslands. Increased green flows in artificial forests are at the expenses of blue flows. We conclude that ensuring adequate levels of water supply for both ecosystems and people at both local and regional scales, large‐scale tree planting effort must be carefully planned.
The vacuolar H+-ATPase (V-ATPase) was first identified as an electrogenic proton pump that acidifies the lumen of intra- and extracellular compartments. The acidic pH generated by V-ATPase is ...important for a wide range of cellular processes as well as acidification-independent processes such as secretion and membrane fusion. In addition to these housekeeping functions, recent studies implicate V-ATPase in the direct regulation and function of signaling pathways. In this review, we describe recent findings on the functions of V-ATPase in growth regulation and tissue physiology.
•V-ATPase-regulated endocytic trafficking is essential for signal transduction.•V-ATPase functions as an intrinsic part of various signaling mechanisms.•Catalytic activity of V-ATPase provides feedback control for intracellular signaling.
Urban heat island (UHI) represents a major anthropogenic modification to the Earth system and its relationship with urban development is poorly understood at a regional scale. Using Aqua MODIS data ...and Landsat TM/ETM+ images, we examined the spatiotemporal trends of the UHI effect (ΔT, relative to the rural reference) along the urban development intensity (UDI) gradient in 32 major Chinese cities from 2003 to 2012. We found that the daytime and nighttime ΔT increased significantly (p<0.05, mostly in linear form) along a rising UDI for 27 and 30 out of 32 cities, respectively. More rapid increases were observed in the southeastern and northwestern parts of China in the day and night, respectively. Moreover, the ΔT trends differed greatly by season and during daytime in particular. The ΔT increased more rapidly in summer than in winter during the day and the reverse occurred at night for most cities. Inter-annually, the ΔT increased significantly in about one-third of the cities during both the day and night times from 2003 to 2012, especially in suburban areas (0.25<UDI≤0.5), with insignificant trends being observed for most of the remaining cities. We also found that the ΔT patterns along the UDI gradient were largely controlled by local climate-vegetation conditions, while that across years were dominated by human activities. Our results highlight the strong and highly diverse urbanization effects on local climate cross China and offer limitations on how these certain methods should be used to quantify UHI intensity over large areas. Furthermore, the impacts of urbanization on climate are complex, thus future research efforts should focus more toward direct observation and physical-based modeling to make credible predictions of the effects.
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•Spatiotemporal trends of the UHI effect (ΔT) were analyzed in China.•ΔT varied greatly across cities, UDI zones, and time periods.•ΔT–UDI patterns were mostly in linear form except few convex or concave ones.•ΔT increased or remained stable from 2003 to 2012 for most cities.•Caution should be paid to the methods to quantify UHI intensity over large areas.
Potassium‐ion batteries (KIBs) are emerging as one of the most promising candidates for large‐scale energy storage owing to the natural abundance of the materials required for their fabrication and ...the fact that their intercalation mechanism is identical to that of lithium‐ion batteries. However, the larger ionic radius of K+ is likely to induce larger volume expansion and sluggish kinetics, resulting in low specific capacity and unsatisfactory cycle stability. A new Ni/Mn‐based layered oxide, P2‐type K0.44Ni0.22Mn0.78O2, is designed and synthesized. A cathode designed using this material delivers a high specific capacity of 125.5 mAh g−1 at 10 mA g−1, good cycle stability with capacity retention of 67% over 500 cycles and fast kinetic properties. In situ X‐ray diffraction recorded for the initial two cycles reveals single solid‐solution processes under P2‐type framework with small volume change of 1.5%. Moreover, a cathode electrolyte interphase layer is observed on the surface of the electrode after cycling with possible components of K2CO3, RCO2K, KOR, KF, etc. A full cell using K0.44Ni0.22Mn0.78O2 as the cathode and soft carbon as the anode also exhibits exceptional performance, with capacity retention of 90% over 500 cycles as well as superior rate performance. These findings suggest P2‐K0.44Ni0.22Mn0.78O2 is a promising candidate as a high‐performance cathode for KIBs.
P2‐K0.44Ni0.22Mn0.78O2 is introduced as a high‐performance cathode material for KIBs. The cathode undergoes a solid‐solution process during K+ reversible insertion/extraction with a small volume change of 1.5%, beneficial to stability. Furthermore, a uniform and stable cathode electrolyte interphase film is formed on its surface.
As one of the key tools for regulating human-ecosystem relations, environmental conservation policies can promote ecological rehabilitation across a variety of spatiotemporal scales. However, ...quantifying the ecological effects of such policies at the regional level is difficult. A case study was conducted at the regional level in the ecologically vulnerable region of the Loess Plateau, China, through the use of several methods including the Universal Soil Loss Equation (USLE), hydrological modeling and multivariate analysis. An assessment of the changes over the period of 2000–2008 in four key ecosystem services was undertaken to determine the effects of the Chinese government's ecological rehabilitation initiatives implemented in 1999. These ecosystem services included water regulation, soil conservation, carbon sequestration and grain production. Significant conversions of farmland to woodland and grassland were found to have resulted in enhanced soil conservation and carbon sequestration, but decreased regional water yield under a warming and drying climate trend. The total grain production increased in spite of a significant decline in farmland acreage. These trends have been attributed to the strong socioeconomic incentives embedded in the ecological rehabilitation policy. Although some positive policy results have been achieved over the last decade, large uncertainty remains regarding long-term policy effects on the sustainability of ecological rehabilitation performance and ecosystem service enhancement. To reduce such uncertainty, this study calls for an adaptive management approach to regional ecological rehabilitation policy to be adopted, with a focus on the dynamic interactions between people and their environments in a changing world.
The excretory-secretory (ES) antigens of Trichinella spiralis muscle larvae (ML) are the most commonly used diagnostic antigens for trichinellosis. Their main disadvantage for the detection of ...anti-Trichinella IgG is false-negative results during the early stage of infection. Additionally, there is an obvious window between clinical symptoms and positive serology.
ELISA with adult worm (AW) ES antigens was used to detect anti-Trichinella IgG in the sera of experimentally infected mice and patients with trichinellosis. The sensitivity and specificity were compared with ELISAs with AW crude antigens and ML ES antigens.
In mice infected with 100 ML, anti-Trichinella IgG were first detected by ELISA with the AW ES antigens, crude antigens and ML ES antigens 8, 12 and 12 days post-infection (dpi), respectively. In mice infected with 500 ML, specific antibodies were first detected by ELISA with the three antigen preparations at 10, 8 and 10 dpi, respectively. The sensitivity of the ELISA with the three antigen preparations for the detection of sera from patients with trichinellosis at 35 dpi was 100%. However, when the patients' sera were collected at 19 dpi, the sensitivities of the ELISAs with the three antigen preparations were 100% (20/20), 100% (20/20) and 75% (15/20), respectively (P < 0.05). The specificities of the ELISAs with the three antigen preparations were 98.11, 95.60 and 89.31%, respectively (P < 0.05).
The sensitivity and specificity of the T. spiralis AW ES antigens were superior to those of the AW crude antigens and ML ES antigens. Thus, the AW ES antigens might serve as potential antigens for the early and specific serodiagnosis of trichinellosis.
A novel environment-friendly method based on stepwise roasting has been proposed to extract vanadium and chromium separately from vanadium slag with high chromium content (V–Cr slag), which consists ...of two stages of sodium roasting–water leaching. Fractional sodium roasting–water leaching is firstly conducted to extract vanadium from the V–Cr slag and 87.9% of vanadium is extracted in optimal conditions. Leaching residue of the fractional roasting stage is then roasted secondarily to extract chromium and 96.4% of chromium is extracted from the leaching residue in optimal conditions. Overall extractions of vanadium and chromium are 98.9% and 96.6%, respectively. Evolution mechanisms of V-bearing and Cr-bearing phases were elucidated by XRD, TG–DSC and SEM-EDS. It is elucidated that V(III) existing as V-spinels in the V–Cr slag is oxidized to water-soluble NaVO3 while Cr(III) remains in the form of Cr-spinels or R2O3 phase (R: Cr, Fe) during the fractional roasting; in secondary roasting, Cr(III) existing as Cr-spinels and R2O3 phase in the leaching residue of fractional roasting stage is oxidized to water-soluble Na2CrO4. Vanadium and chromium have thus been extracted separately and thoroughly at the extraction procedure by controlling the roasting extent of V–Cr slag via the proposed stepwise roasting method. The established method provides new insights for comprehensive utilization of complex minerals containing multiple valuable elements.
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•Stepwise roasting method has been realized to asynchronously extract V and Cr.•Toxic tailings are recycled into the production of V–Cr slag for cleaner purpose.•Core/shell distribution of Cr/V in spinel grain of V–Cr slag has been discovered.•V is extracted by fractional roasting while Cr is extracted by secondary roasting.•98.9% of V and 96.6% of Cr can be extracted from V–Cr slag by the proposed method.
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