We introduce for each quiver Q and each algebraic oriented cohomology theory A, the cohomological Hall algebra (CoHA) of Q, as the A‐homology of the moduli of representations of the preprojective ...algebra of Q. This generalizes the K‐theoretic Hall algebra of commuting varieties defined by Schiffmann–Vasserot ‘The elliptic Hall algebra and the K‐theory of the Hilbert scheme of A2’, Duke Math. J. 162 (2013) 279–366.. When A is the Morava K‐theory, we show evidence that this algebra is a candidate for Lusztig's reformulated conjecture on modular representations of algebraic groups Lusztig, ‘On the character of certain irreducible modular representations’, Represent. Theory 19 (2015) 3–8; Joint Seminar, Mathematical Sciences Research Institute, October 28, 2014.
We construct an action of the preprojective CoHA on the A‐homology of Nakajima quiver varieties. We compare this with the action of the Borel subalgebra of Yangian when A is the intersection theory. We also give a shuffle algebra description of this CoHA in terms of the underlying formal group law of A. As applications, we obtain a shuffle description of the Yangian.
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As one of the earliest remote sensing indices, the Normalized Difference Vegetation Index (NDVI) has been employed extensively for vegetation research. However, despite an abundance of NDVI review ...articles, these studies are predominantly limited to either one subject area or one area, with systematic NDVI reviews being relatively rare. Bibliometrics is a useful method of analyzing scientific literature that has been widely used in many disciplines; however, it has not yet been applied to comprehensively analyze NDVI research. Therefore, we used bibliometrics and scientific mapping methods to analyze citation data retrieved from the Web of Science during 1985–2021 with NDVI as the topic. According to the analysis results, the amount of NDVI research increased exponentially during the study period, and the related research fields became increasingly varied. Moreover, a greater number of satellite and aerial remote sensing platforms resulted in more diverse NDVI data sources. In future, machine learning methods and cloud computing platforms led by Google Earth Engine will substantially improve the accuracy and production efficiency of NDVI data products for more effective global research.
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Endometritis is an inflammatory change in the structure of the endometrium due to various causes and is a common cause of infertility. Studies have confirmed that microRNAs (miRNAs) play a key ...regulatory role in various inflammatory diseases. However, the miRNA‐mediated mechanism of endometrial inflammation induced by lipopolysaccharides (LPS) remains unclear. In this study, real‐time quantitative polymerase chain reaction, Western blot analysis, immunofluorescence and Rac family small GTPase 1 (Rac1) interference were used to reveal the overexpression of miR‐488 in the LPS‐induced bovine uterus, and the effect of protein kinase B κ‐light chain enhancement of the nuclear factor‐activated B cells (AKT/NF‐κB) pathway in intimal epithelial cells. The results showed that the expression of inflammatory cytokines such as interleukin‐1β (IL‐1β), IL‐6, and tumor necrosis factor‐α in the experimental group was significantly lower than that in the control group when miR‐488 was overexpressed. Similar results were observed in the expression levels of p‐AKT, p‐IKK, and p‐p65 proteins. In addition, the dual‐luciferase reporter system confirmed that miRNA‐488 may directly target the 3′‐untranslated region of Rac1. In turn, the expression of Rac1 was inhibited. Moreover, the nuclear translocation of NF‐κB was inhibited, and meanwhile, the accumulation of reactive oxygen species (ROS) in the cells was reduced. Thus, we provide basic data for the negative regulation of miR‐488 in LPS‐induced inflammation by inhibiting ROS production and the AKT/NF‐kB pathway in intimal epithelial cells.
miR‐488 attenuates lipopolysaccharides (LPS)‐induced BEND cell inflammatory response by inhibiting translation of Rac family small GTPase 1 (Rac1) and reducing reactive oxygen species (ROS) accumulation in cells. Our results support the fact that the inflammatory response nature of BEND cells stimulated by LPS stimulates the intracellular accumulation of ROS and the activation of the AKT/NF‐κB signaling pathway by miR‐488 directly targeting the negative phase of Rac1.
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We define an action of the (double of) Cohomological Hall algebra of Kontsevich and Soibelman on the cohomology of the moduli space of spiked instantons of Nekrasov. We identify this action with the ...one of the affine Yangian of
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of Gaiotto and Rapčák. We conjecture that our approach works for a big class of Calabi–Yau categories, including those associated with toric Calabi–Yau 3-folds.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, ODKLJ, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Vegetation phenology in spring has received much attention for its importance to terrestrial ecosystem carbon exchange and climate-biosphere interactions studies. Through control on surface water and ...heat balance, snow cover largely impacts on spring vegetation phenology. However, under the background of global warming and rapid reduction of spring snow cover extent across the Northern Hemisphere (NH), the responses of spring vegetation phenology have not been well documented. Using two satellite-derived land cover dynamic datasets and 420 in situ vegetation phenology observations from five filed datasets, this study evaluated the accuracy of satellite-derived vegetation phenology datasets and explored the changes of start of the growing season (SOS) across the NH snow-covered landmass for the period 2001-2014. Compared with MEaSUREs VIPPHEN, the MODIS SOS maps displayed higher accuracy in capture the real SOS climatology by validating with in situ observations (R2 = 0.67, bias = −3.99 d). Moreover, evidences from MODIS SOS maps pointed out that the SOS advanced by approximately 2.36 d in NH middle to high latitudes (43.5°N-70.0°N), but delayed by about 0.53 d in lower latitudes (33.0°N-43.5°N) from 2001 to 2014. The contrast SOS anomalies across the NH snow-covered landmass were further proved by changes in spring NDVI derived from GIMMS in the corresponding period. In addition, the observed changes in SOS were consistent with the spatiotemporal pattern of spring snow end date found in previous studies, indicating vegetation phenology changes should be taken into account in estimating the impacts of snow in climate-biosphere interactions studies.
Monitoring land-use and land-cover change (LUCC) is extremely important in the sustainable development and management of terrestrial ecosystems. Taking the Heilongjiang (Amur) River Basin as the ...study area, this study aimed to identify the spatiotemporal characteristics of land cover at the entire basin and at the country levels of the three countries using the land-use change index, frequency statistics and land-cover change degree. The results showed that: (1) The LULC types were mainly forest land and grassland (accounting for nearly 83% in total) from 2001 to 2019. The main land-cover types in China, Russia and Mongolia were forest land, forest land and grassland, respectively. (2) The area of urban land, cropland and wetland increased significantly from 2001 to 2019, while the area of forest land and bare land decreased during this time. In general, the ecological environment has greatly improved over the last 19 years, although the relevant ecological restoration still needs to be further implemented. The findings can provide a scientific basis for ecological protection and sustainable development in the Heilongjiang (Amur) River Basin. The approaches here are also applicable to land-cover change research in other similar regions.
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•This study estimated groundwater storage information of China.•The groundwater storage was certificated to be reliable and accurate.•The causes of groundwater storage changes in different basins ...were analyzed.
As an important freshwater resource, groundwater is of great significance to agriculture, industry, and daily life. The investigation of groundwater storage (GWS) in different regions of China is critical for water resource management and conservation. However, previous studies used different methods and data to monitor GWS in different regions of China, which made their results difficult to compare and cross validate. Here, we used a unified method by the Gravity Recovery and Climate Experiment (GRACE) satellite data and global models to study the variations of GWS in 10 major basins in China from April 2002 to December 2016. Results showed that GWS in the i) Songhua River basin (SRB), Liao River basin (LRB), Haihe River basin (HRB), Yellow River basin (YRB), Huaihe River basin (HHRB), and southeast basin (SEB) exhibited decreasing trends, ii) Yangtze River basin (YZRB) and Pearl River basin (PRB) presented increasing trends, and iii) southwest basin (SWB) and continental basin (CB) displayed both decreasing and increasing trends during the study period. These results were validated by comparing them with a large number of previous studies, which revealed that they were accurate and reliable. Comparing with the climate data and bulletin data, the analysis of causes for these trends indicated that drought and irrigation water-use led to a decline in GWS in several basins of northern China. The decreasing trend of GWS in the SEB was related to water use for production, whereas groundwater recharge from precipitation drove the increasing trends of GWS in the YZRB and PRB. In contrast, the wide geographical areas and complex factors of the SWB and CB led to the increasing–decreasing trends of GWS. This study enriches the GWS for China over the past decade, especially for SEB, PRB, and CB with rare GWS information. It will be helpful for the country’s groundwater resource management and systematic water conservation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
As a sensitive climate change indicator, global multi‐depth soil moisture (SM) has undergone great variation due to warming trends during the past decades. Here, we investigate the evolutionary ...pattern of SM and then carry out an attribution analysis from climate and human perspectives. The results reveal an unbalanced surface and rootzone variation trend during 1980–2020. The surface soil had approximately equal proportions of drying and wetting. Nonetheless, the percentage of the wetting region is significantly higher than that of the drying region for rootzone soil. The significantly drying region is mainly distributed in habitable areas, while the remarkably wetting region is usually located in the harsh climate and tropical humid zones. According to the attribution analysis using the Feature Importance Index of the Random Forest model, Pearson correlation coefficient, Maximum information coefficient, Spearman rank correlation coefficient, and Granger causality with 99% statistical significance, both climatic and human factors presented significant impacts on SM. Specifically, air temperature and evaporation are thought to be the primary climatic factors affecting the seasonal and long‐term variability of SM, respectively. Irrigation water withdrawal is regarded as the dominant driving force of SM variation among six human water withdrawals, and domestic and electricity water withdrawals play indispensable roles in SM fluctuation. Additionally, SM also provides profound feedbacks on climatic factors and human water withdrawals. The global spatial‐temporal SM variation along with warming temperatures could seriously risk food security and sustainable development, which needs to be addressed.
Key Points
Drying regions are distributed in habitable areas, while wetting regions are located in the harsh climate and tropical humid zones
Air temperature and evaporation are thought to be the primary climatic factors affecting the seasonal and long‐term variability of soil moisture (SM)
Irrigation water withdrawal is regarded as the dominant driving force of SM variation among the six human water withdrawals
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Prader-Willi syndrome (PWS) is caused by the absence of paternally expressed, maternally silenced genes at 15q11-q13. We report four individuals with truncating mutations on the paternal allele of ...MAGEL2, a gene within the PWS domain. The first subject was ascertained by whole-genome sequencing analysis for PWS features. Three additional subjects were identified by reviewing the results of exome sequencing of 1,248 cases in a clinical laboratory. All four subjects had autism spectrum disorder (ASD), intellectual disability and a varying degree of clinical and behavioral features of PWS. These findings suggest that MAGEL2 is a new gene causing complex ASD and that MAGEL2 loss of function can contribute to several aspects of the PWS phenotype.
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Precipitation is an important controlling parameter for land surface processes, and is crucial to ecological, environmental, and hydrological modeling. In this study, we propose a spatial downscaling ...approach based on precipitation–land surface characteristics. Land surface temperature features were introduced as new variables in addition to the Normalized Difference Vegetation Index (NDVI) and Digital Elevation Model (DEM) to improve the spatial downscaling algorithm. Two machine learning algorithms, Random Forests (RF) and support vector machine (SVM), were implemented to downscale the yearly Tropical Rainfall Measuring Mission 3B43 V7 (TRMM 3B43 V7) precipitation data from 25 km to 1 km over the Tibetan Plateau area, and the downscaled results were validated on the basis of observations from meteorological stations and comparisons with previous downscaling algorithms. According to the validation results, the RF and SVM-based models produced higher accuracy than the exponential regression (ER) model and multiple linear regression (MLR) model. The downscaled results also had higher accuracy than the original TRMM 3B43 V7 dataset. Moreover, models including land surface temperature variables (LSTs) performed better than those without LSTs, indicating the significance of considering precipitation–land surface temperature when downscaling TRMM 3B43 V7 precipitation data. The RF model with only NDVI and DEM produced much worse accuracy than the SVM model with the same variables. This indicates that the Random Forests algorithm is more sensitive to LSTs than the SVM when downscaling yearly TRMM 3B43 V7 precipitation data over Tibetan Plateau. Moreover, the precipitation–LSTs relationship is more instantaneous, making it more likely to downscale precipitation at a monthly or weekly temporal scale.
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