The distinct spatiotemporal characteristics of the hourly intense precipitation (HIP) over the Pearl River Delta (PRD) and the impact of urbanization before and after the monsoon onset from 1972 to 2021 have been investigated using the hourly rain gauge data, nighttime lights data, and land use data. The results show a significant decreasing trend of HIP during the pre-monsoon onset period and a notable increasing trend during the post-monsoon onset period over the past five decades. However, compared to rural areas, rapid urbanization in the PRD after the mid-1990s weakens the HIP reduction, especially in the inland cities of PRD before the onset of the monsoon and enhances the HIP increase, particularly in the southeast inland and west coast cities after the onset of the monsoon. After rapid urbanization, the peak time of HIP has been postponed from 14 LST to 17 LST during the pre-monsoon onset period. HIP tends to occur more frequently in urban areas in the morning (10-12 LST) and evening (19-24 LST) compared to rural areas. In contrast, the impact of urbanization on the diurnal variation of HIP is not obvious during the post-monsoon period, despite higher frequencies of HIP occurring during the daytime (10-15 LST) in the urban areas after rapid urbanization. These findings provide valuable insights for forecasting HIP in urban agglomerations.

The study explores the characteristics of morning extreme precipitation (MEP) during the pre-summer in inland Guangdong. Based on the principal modes, MEP events can be classified into four groups. The first group of MEP (G1) is a typical southeastward-propagating rainfall system originating from the northwestern mountains. This is caused by the strongest accelerated southwesterly winds at night, which bring abundant moist and warm air from the South China Sea (SCS) along with the shear line and the highest convective available potential energy (CAPE). The second group of MEP (G2) is warm-sector heavy rainfall with large-scale warming and higher CAPE. This local rainfall system originates in the south of Nanling mountains at night and reaches its mature stage in the morning. The rainfall system of the third group (G3) originates in central Guangxi and propagates to the southern inland region. The southeasterly winds in Guangxi intensify at night due to the anomalous cyclonic circulation. However, in the morning, the easterly winds shift to the westerlies, favoring eastward propagation. After SCS monsoon onset, cold air intrudes southward, colliding with moist warm air from the SCS, leading to heavy frontal precipitation in the inland region, classified as the fourth group MEP (G4).

During the period preceding the vegetation growing season (GS), temperature emerges as the pivotal factor determining phenology in northern terrestrial ecosystems. Despite extensive research on the impact of daily mean temperature (Tmean) during the preseason period, the influence of diurnal temperature range (DTR) on vegetation photosynthetic phenology (i.e., the impact of the plant photosynthetic cycle on seasonal time scale) has largely been neglected. Using a long-term vegetation photosynthetic phenology dataset and historical climate data, we examine vegetation photosynthetic phenology dynamics and responses to climate change across the mid–high latitudes of the Northern Hemisphere from 2001 to 2020. Our data reveal an advancing trend in the start of the GS (SOS) by −0.15 days per year (days yr−1), affecting 72.1% of the studied area. This is particularly pronounced in western Canada, Alaska, eastern Asia, and latitudes north of 60°N. Conversely, the end of the GS (EOS) displays a delaying trend of 0.17 days yr−1, impacting 62.4% of the studied area, especially northern North America and northern Eurasia. The collective influence of an earlier SOS and a delayed EOS has resulted in the notably prolonged length of the GS (LOS) by 0.32 days yr−1 in the last two decades, affecting 70.9% of the studied area, with Eurasia and western North America being particularly noteworthy. Partial correlation coefficients of the SOS with preseason Tmean, DTR, and accumulated precipitation exhibited negative values in 98.4%, 93.0%, and 39.2% of the study area, respectively. However, there were distinct regional variations in the influence of climate factors on the EOS. The partial correlation coefficients of the EOS with preseason Tmean, DTR, and precipitation were positive in 58.6%, 50.1%, and 36.3% of the region, respectively. Our findings unveil the intricate mechanisms influencing vegetation photosynthetic phenology, holding crucial significance in understanding the dynamics of carbon sequestration within terrestrial ecosystems amidst climate change.

The presummer intense regional rainfall events (RREs) over the Pearl River Delta (PRD) metropolitan region have been defined using rainy stations, maximum instantaneous regional rainfall coefficient (RRCt) and maximum rainfall intensity based on the rain gauge data from 2008 to 2017. Most of intense RREs with the maximum rainfall intensity about 20-60 mm.h(-1) and the lifetime shorter than 24 h have the primary rainfall peak from noon to afternoon. Based on the rainfall pattern at 3 h prior to the events start, the intense RREs can be classified into two groups that one is southeastward propagation mode originating from the northwestern mountains of PRD and another is coastal mode from South China Sea (SCS). During the premonsoon-onset period, the first type of RREs is the main mode causing the heavy rain in the cities of the inland region owing to the anomalous cold air from north confronting the wet and warm air from south with the increased southwesterly winds resulting in the strengthening frontal zone and moisture convergence. After the summer monsoon onset, the main rainfall pattern changes to the coastal mode having the significant impact on the coastal cities. The obvious anomalous cyclonic circulation related with the increased moisture convergence in the coastal regions providing the favourable conditions of the convection initiation and development. The study of the characteristics and evolution process of preceding intense RREs can improve the forecasting skills and reduce the risk of urban inundation.

Background: Mangrove forests are a significant contributor to the global carbon cycle, and the accurate estimation of their gross primary productivity（GPP） is essential for understanding the carbon budget within blue carbon ecosystems. Little attention has been given to the investigation of spatiotemporal patterns and ecological variations within mangrove ecosystems, as well as the quantitative analysis of the influence of geo-environmental factors on time-series estimations of mangrove GPP.Methods: This study explored the spatiotemporal dynamics of mangrove GPP from 2000 to 2020 in Gaoqiao Mangrove Reserve, China. A leaf area index（LAI）-based light-use efficiency（LUE） model was combined with Landsat data on Google Earth Engine（GEE） to reveal the variations in mangrove GPP using the Mann-Kendall（MK） test and Theil-Sen median trend. Moreover, the spatiotemporal patterns and ecological variations in mangrove ecosystems across regions were explored using four landscape indicators. Furthermore, the effects of six geo-environmental factors（species distribution, offshore distance, elevation, slope, planar curvature and profile curvature） on GPP were investigated using Geodetector and multi-scale geo-weighted regression（MGWR）.Results: The results showed that the mangrove forest in the study area experienced an area loss from 766.26 ha in2000 to 718.29 ha in 2020, mainly due to the conversion to farming, terrestrial forest and aquaculture zones.Landscape patterns indicated high levels of vegetation aggregation near water bodies and aquaculture zones, and low levels of aggregation but high species diversity and distribution density near building zone. The mean value of mangrove GPP continuously increased from 6.35 g C·m -2 ·d -1 in 2000 to 8.33 g C·m -2 ·d -1 in 2020, with 23.21%of areas showing a highly and significantly increasing trend（trend value ＞ 0.50）. The Geodetector and MGWR analyses showed that species distribution, offshore distance and elevation contributed most to the GPP variations.Conclusions: These results provide guidelines for selecting GPP products, and the combination of Geodetector and MGWR based on multiple geo-environmental factors could quantitatively capture the mode, direction, pathway and intensity of the influencing factors on mangrove GPP variation. The findings provide a foundation for understanding the spatiotemporal dynamics of mangrove GPP at the landscape or regional scale.

The response of boreal vegetation to global warming has shown a weakening trend over the last three decades. However, in previous studies, models of vegetation activity responses to temperature change have often only considered changes in the mean daily temperature (T-mean), with the diurnal temperature range (DTR) being neglected. The goal of this study was to evaluate the temporal trends of the relationships between two temperature factors (T-mean and DTR) and the vegetation activity across the boreal regions on both annual and seasonal timescales, by simultaneously employing satellite and climate datasets. We found that the interannual partial correlation between the growing season (GS) NDVI and T-mean (RNDVI-Tmean) has shown a significant decreasing trend over the last 34 years. At the seasonal scale, the RNDVI-Tmean showed a significant upward trend in the spring, while in the summer and autumn, the RNDVI-Tmean exhibited a significant downward trend. The temporal trend characteristics of the partial correlation between the NDVI and DTR (RNDVI-DTR), at both the GS and seasonal scales, were fully consistent with the RNDVI-Tmean. The area with a significant decrease in the GS RNDVI-Tmean and RNDVI-DTR accounted for approximately 44.4% and 41.2% of the boreal region with the 17-year moving window, respectively. In stark contrast, the area exhibiting a significant increasing trend in the GS RNDVI-Tmean and RNDVI-DTR accounted for only approximately 22.3% and 25.8% of the boreal region with the 17-year moving window, respectively. With respect to the seasonal patterns of the RNDVI-Tmean and RNDVI-DTR, the area with a significant upward trend in the spring was greater than that with a significant downward trend. Nevertheless, more areas had a significant downward trend in the RNDVI-Tmean and RNDVI-DTR in summer and autumn than a significant upward trend. Overall, our research reveals a weakening trend in the impact of temperature on the vegetation activity in the boreal regions and contributes to a deeper understanding of the vegetation response to global warming.

基于1961-2021年粤港澳大湾区31个国家气象观测站逐日降水资料,采用线性趋势分析、趋势系数计算、Mann-Kendall突变检验等方法分析了大湾区年及前、后汛期的暴雨日数、暴雨量、暴雨强度和暴雨贡献率的气候特征及变化.结果表明,近61 a大湾区平均年暴雨日数和大暴雨日数分别为8.3 d和1.8 d,有87%的暴雨发生在汛期,其中前、后汛期各占47%和40%.近61 a大湾区31个站平均的年及前、后汛期暴雨日数、暴雨量、暴雨贡献率、暴雨强度的变化趋势均不明显,但广州、怀集、斗门等6个站暴雨量变化趋势显著.大湾区年及前、后汛期暴雨日数及其变化速率均高于广东省同期.香港、澳门和广州的暴雨特征对比分析显示,香港近61 a平均暴雨量、暴雨日数、暴雨强度和暴雨贡献率均为最大,澳门次之,广州最小,但广州年和前汛期暴雨量、暴雨日数及前汛期暴雨贡献率的变化速率最大.

Background & Aims: The persistence of covalently closed circular DNA (cccDNA) in infected hepatocytes is the major barrier preventing viral eradication with existing therapies in patients with chronic hepatitis B. Therapeutic agents that can eliminate cccDNA are urgently needed to achieve viral eradication and thus HBV cure. Methods: A phenotypic assay with HBV-infected primary human hepatocytes (PHHs) was employed to screen for novel cccDNA inhibitors. A HBVcircle mouse model and a uPA-SCID (urokinase-type plasminogen activator-severe combined immunodefi-ciency) humanized liver mouse model were used to evaluate the anti-HBV efficacy of the discovered cccDNA inhibitors.Results: Potent and dose-dependent reductions in extracellular HBV DNA, HBsAg, and HBeAg levels were achieved upon the initiation of ccc_R08 treatment two days after the HBV infection of PHHs. More importantly, the level of cccDNA was specifically reduced by ccc_R08, while it did not obviously affect mitochondrial DNA. Additionally, ccc_R08 showed no significant cytotoxicity in PHHs or in multiple proliferating cell lines. The twice daily oral administration of ccc_R08 to HBVcircle model mice, which contained surrogate cccDNA molecules, significantly decreased the serum levels of HBV DNA and antigens, and these effects were sustained during the off-treatment follow-up period. Moreover, at the end of follow-up, the levels of surrogate cccDNA molecules in the livers of ccc_R08-treated HBVcircle mice were reduced to below the lower limit of quantification.Conclusions: We have discovered a small-molecule cccDNA inhibitor that reduces HBV cccDNA levels. cccDNA inhibitors potentially represent a new approach to completely cure patients chronically infected with HBV.(c) 2022 Published by Elsevier B.V. on behalf of European Association for the Study of the Liver.

准确的灌溉耕地位置分布信息是地球系统科学和气候变化等研究领域的基础,它关乎我们国家的粮食安全和水资源安全,对水循环、能量循环研究具有重要的意义.遥感灌溉耕地制图研究主要分为局地研究、区域研究和全球研究三类.目前,基于遥感的灌溉耕地制图研究大多数都集中在局地尺度上,其中,目视解译法和数字图像分类法是在局地尺度研究中最常见的方法;在区域尺度上,最常见的手段是使用中等分辨率的卫星图像进行多时段的时间序列分析,从而实现灌区地图的绘制;当前全球尺度的灌溉位置分布研究工作,由于在数据获取方面受到的的客观限制,使其在灌溉分类结果上存在较大的不确定性.近年来,国际国内出现了一些灌溉产品,由于各种原因,这些灌溉产品存在精度不高、分类不可靠等问题.然而,由于技术的进步,数据融合技术、微波遥感技术及大量其他辅助数据在大区域绘制灌溉地图方面提供了更大的可能性.为此,极有必要系统回顾灌溉耕地识别制图研究的发展历程,总结当前研究的现状及存在的不足,为进一步开展灌溉耕地制图方法研究和提高灌溉识别精度提供参考.

The distribution of global warming has been varying both diurnally and seasonally. Little is known about the spatiotemporal variations in the relationships between vegetation greenness and day- and night-time warming during the last decades. We investigated the global inter- and intra-annual responses of vegetation greenness to the diurnal asymmetric warming during the period of 1982–2015, using the normalized different vegetation index (NDVI, a robust proxy for vegetation greenness) obtained from the NOAA/AVHRR NDVI GIMMS3g dataset and the monthly average daily maximum (Tmax) and minimum temperature (Tmin) obtained from the gridded Climate Research Unit, University of East Anglia. Several findings were obtained: (1) The strength of the relationship between vegetation greenness and the diurnal temperature varied on inter-annual and seasonal timescales, indicating generally weakening warming effects on the vegetation activity across the global. (2) The decline in vegetation response to Tmax occurred mainly in the mid-latitudes of the world and in the high latitudes of the northern hemisphere, whereas the decline in the vegetation response to Tmin primarily concentrated in low latitudes. The percentage of areas with a significantly negative trend in the partial correlation coefficient between vegetation greenness and diurnal temperature was greater than that of the areas showing the significant positive trend. (3) The trends in the correlation between vegetation greenness and diurnal warming showed a complex spatial pattern: the majority of the study areas had undergone a significant declining strength in the vegetation greenness response to Tmax in all seasons and to Tmin in seasons except autumn. These findings are expected to have important implications for studying the diurnal asymmetry warming and its effect on the terrestrial ecosystem.

Chronic hepatitis B virus (HBV) infection is a worldwide disease that causes thousands of deaths per year. Currently, there is no therapeutic that can completely cure already infected HBV patients due to the inability of humans to eliminate covalently closed circular DNA (cccDNA), which serves as the template to (re)initiate an infection even after prolonged viral suppression. Through phenotypic screening, we discovered xanthone series hits as novel HBV cccDNA reducers, and subsequent structure optimization led to the identification of a lead compound with improved antiviral activity and pharmacokinetic profiles. A representative compound 59 demonstrated good potency and oral bioavailability with no cellular toxicity. In an HBVcircle mouse model, compound 59 showed excellent efficacy in significantly reducing HBV antigens, DNA, and intrahepatic cccDNA levels.

利用龙门县内南昆山、气象观测基地和沈村3 个不同的大气负氧离子监测站数据,对龙门县负氧离子时空特征进行分析.结果表明:龙门县负氧离子资源丰富(年均浓度为2 989 cm-3),其空间分布与植被覆盖度对应呈现为西高东低趋势.高植被覆盖度区域南昆山站的负氧离子浓度日变化不明显,而低植被覆盖度区域气象观测基地和沈村站存在夜间、早晨高,下午、傍晚低的特征.季节变化来看,龙门县负氧离子浓度呈现春夏高、秋冬低的分布趋势.

以粤港澳大湾区为例,利用卫星遥感资料结合大气化学模式模拟,分析2003-2018年城市热岛强度、气溶胶光学厚度的变化规律,定性和定量研究气溶胶对白天城市热岛强度的影响.结果 表明:2003-2018年粤港澳大湾区城市热岛强度呈波动上升趋势,夏季热岛强度最大,冬季热岛强度最小;气溶胶光学厚度呈波动下降趋势,春季气溶胶光学厚度最大,冬季气溶胶光学厚度最小.在年际和季节尺度,城市热岛强度与城区、郊区气溶胶光学厚度之差均里弱的正相关.基于WRF-Chem的模拟实验表明,气溶胶的存在导致城区、郊区地表向下总辐射减少、地表温度降低,且城区地表向下总辐射减少多于郊区、降温幅度大于郊区,进而导致了热岛强度减弱.气溶胶对城市热岛强度的贡献率为-2.187％,冬季贡献率绝对值略高于夏季.

A high-throughput screen of a Roche internal chemical library based on inhibition of the respiratory syncytial virus (RSV)-induced cytopathic effect (CPE) on HEp-2 cells was performed to identify RSV inhibitors. Over 2,000 hits were identified and confirmed to be efficacious against RSV infection in vitro .

Long time series of vegetation productivity products are significant for the research of global carbon cycle and climate change. In this article, the 0.05° global gross primary productivity (GPP) and net primary productivity (NPP) products from 1981 to 2018 were estimated by using the improved multisource data synergized quantitative (MuSyQ) NPP algorithm. The model was based on the fraction of absorbed photosynthetically active radiation (FPAR) and leaf area index (LAI) data from the global land surface satellite (GLASS) dataset, the light use efficiency (LUE) from the parameterization approach with the clearness index (CI), the ERA-Interim meteorological data, and other environmental factors. The results suggested that the accuracy of the MuSyQ GPP product was slightly higher than that of the MOD17 GPP product when compared with the FLUXNET GPP, especially for the evergreen broadleaf forest (EBF), deciduous broadleaf forest (DBF), wetland (WET), cropland (CRO), woody savanna (WSAV), and closed shrubland (CSH) land types. MuSyQ NPP product also has higher accuracy [ R 2 = 0.81, RMSE = 214.6 gC/(m 2 year)] than MOD17 NPP [ R 2 = 0.55, RMSE = 214.7 gC/(m 2 year)] when compared with the BigFoot NPP, which indicated the reliability of the improved MuSyQ-NPP algorithm in estimating global NPP. Our results showed a significant upward trend in global NPP, which was most affected by FPAR, followed by LUE, temperature, and PAR. The average NPP declined significantly in Asia and Amazon tropical rainforests and increased significantly in Africa tropical rainforest, which were affected by the local deforestation or the forest expansion, and also the climate factors.

Accurate spatial information about irrigation is crucial to a variety of applications, such as water resources management, water exchange between the land surface and atmosphere, climate change, hydrological cycle, food security, and agricultural planning. Our study proposes a new method for extracting cropland irrigation information using statistical data, mean annual precipitation and Moderate Resolution Imaging Spectroradiometer (MODIS) land cover type data and surface reflectance data. The approach is based on comparing the land surface water index (LSWI) of cropland pixels to that of adjacent forest pixels with similar normalized difference vegetation index (NDVI). In our study, we validated the approach over mainland China with 612 reference samples (231 irrigated and 381 non-irrigated) and found the accuracy of 62.09%. Validation with statistical data also showed that our method explained 86.67 and 58.87% of the spatial variation in irrigated area at the provincial and prefecture levels, respectively. We further compared our new map to existing datasets of FAO/UF, IWMI, Zhu and statistical data, and found a good agreement with the irrigated area distribution from Zhu's dataset. Results show that our method is an effective method apply to mapping irrigated regions and monitoring their yearly changes. Because the method does not depend on training samples, it can be easily repeated to other regions.

Winter wheat is a staple food crop for most of the world's population, and the area and spatial distribution of winter wheat are key elements in estimating crop production and ensuring food security. However, winter wheat planting areas contain substantial spatial heterogeneity with mixed pixels for coarse- and moderate-resolution satellite data, leading to large errors in crop acreage estimation. This study has developed a phenology-based approach using moderate-resolution (1 km per pixel) satellite data to estimate sub-pixel planting fractions of winter wheat. Based on unmanned aerial vehicle (UAV) observations, the unique characteristics of winter wheat with high vegetation index values at the heading stage (May) and low values at the ripening stage (June) were investigated. The differences in vegetation index between heading and ripening stages increased with the planting fraction of winter wheat, and therefore the planting fractions were estimated by comparing the NDVI differences of a given pixel with those of predetermined pure winter wheat and non-winter wheat pixels. This approach was evaluated using aerial images and agricultural statistical data in an intensive agricultural region, Shandong Province in North China. The method explained 85% and 60% of the spatial variation in municipal- and county-level statistical data, respectively. More importantly, the predetermined pure winter wheat and non-winter wheat pixels can be automatically identified using MODIS data according to their NDVI differences, which strengthens the potential to use this method at regional and global scales without any field observations as references.

Ziresovir (RO-0529, AK0529) is reported here for the first time as a promising respiratory syncytial virus (RSV) fusion (F) protein inhibitor that currently is in phase 2 clinical trials. This article describes the process of RO-0529 as a potent, selective, and orally bioavailable RSV F protein inhibitor and highlights the in vitro and in vivo anti-RSV activities and pharmacokinetics in animal species. RO-0529 demonstrates single-digit nM EC50 potency against laboratory strains, as well as clinical isolates of RSV in cellular assays, and more than one log viral load reduction in BALB/c mouse model of RSV viral infection. RO-0529 was proven to be a specific RSV F protein inhibitor by identification of drug resistant mutations of D486N, D489V, and D489Y in RSV F protein and the inhibition of RSV F protein-induced cell-cell fusion in cellular assays.

Accurate information about the location and extent of irrigation is fundamental to many aspects of food security and water resource management. This study develops a new method for identifying irrigation in northeastern China by comparing canopy moisture between the cropland and adjacent natural ecosystems (i.e., forests). This method is based on two basic assumptions, which we validated using field survey data. First, the canopy moisture of irrigated cropland, indicated by a satellite-based land surface water index (LSWI), is higher than that of the adjacent forest. Second, the difference in LSWI between irrigation cropland and forest is larger in arid regions than in humid regions. Based on the field survey and statistical dataset, our method performed well in indicating spatial variations of irrigated areas. Results from this study suggest that our method is a promising tool for mapping irrigated areas, as it is a general and repeatable method that does not rely on training samples and can be applied to other regions.

The replication of hepatitis B virus (HBV) may be modulated by a variety of cell signaling pathways, including the phosphatidylinositol 3‑kinase (PI3K)‑RAC‑α serine/threonine‑protein kinase (AKT)‑serine/threonine‑protein kinase mTOR (mTOR) pathway. The aim of the present study was to determine the regulatory effects of this pathway on the infection and replication of HBV. The results indicated that the HBV entry process may activate the AKT pathway, as demonstrated by AKT phosphorylation in HBV natural infection. However, inhibition of AKT phosphorylation by short‑term treatment with AKT inhibitors was unable to block HBV entry, which suggested that AKT activation induced by HBV infection is not essential for viral entry process. Prolonged treatment with PI3K‑AKT‑mTOR pathway inhibitors markedly promoted HBV replication in HBV replicating and natural infection models. The PI3K‑AKT‑mTOR pathway was therefore identified to be a negative regulator of HBV replication. These inhibitors enhanced the replication and transcription of HBV in an HBx‑dependent way. The results additionally indicated that a PI3K inhibitor, Ly294002, inhibited the secretion of the small surface antigen of HBV in a PI3K‑AKT‑independent manner. The inhibitor Ly294002 may be used as a tool for the drug development of surface antigen secretion inhibitors.