Spatiotemporal Patterns and Cause Analysis of PM 2.5

According to the monthly comprehensive air index ranking in China in 2016, Beijing ranked in the bottom tenth three times, indicating that the air pollution situation is very serious compared to other cities in China. In this study, we chose 23 urban environmental assessment points, which covered all districts and counties in Beijing. We used ArcGIS software to analyze atmospheric concentrations of particulate matter with a diameter < 2.5 μm (PM2.5) for each month of 2016 in each district/county of Beijing. Our results showed that PM2.5 concentrations in winter and spring were generally higher than those in summer and autumn. The higher monthly average PM2.5 concentrations were primarily in the southwest and southeast areas. The higher annual average values were distributed in Fangshan, Daxing, and Tongzhou, which were closely related to the high terrain in the northwest and the low-lying terrain in the southeast, the “Beijing Bay” terrain, and local climatic conditions. The temporal and spatial distributions of PM2.5 constitute a warning signal for human life and production during different seasons and regions

Influences of Urban Expansion on Urban Heat Island in Beijing during 1989–2010

Beijing has experienced rapid urbanization and associated urban heat island (UHI) effects. This study aimed at analyzing the impact of urban form on UHI in Beijing using TM/ETM images between 1989 and 2010. Spatial analysis was proposed to explore the relationships between area, compactness ratio, the gravity centers of urban land, and UHI. The UHI in Beijing spatially represented a “NE-SW” spindle. The land surface temperature (LST) was higher in south than in north. Urban Heat Island Ratio Index (URI) was well interrelated with urban land area in different zones. Under the similar urban land area condition, UHI and compactness ratio of urban land were in positive correlation. The moving direction of the UHI gravity center was basically in agreement with urban land sprawl. The encroachment of urban land on suburban land is the leading source of UHI effect. The results suggest that urban design based on urban form would be effective for regulating the thermal environment

Regulation of T cell receptor signaling by activation-induced zinc influx

Zinc enhances TCR signaling in part by inhibiting Shp-1 recruitment to the TCR synapse

Detecting spatiotemporal dynamic landscape patterns using remote sensing and the lacunarity index: a case study of Haikou City, China

Quantifying the landscape pattern and its dynamics is essential for the monitoring and assessment of the ecological consequences of urbanization. As one of the Special Economic Zones, Haikou is one of the fastest growing regions among all Chinese cities, owing to rapid real estate development. Using a GIS-based land-use dataset from 1986, 1996, and 2000, in combination with a lacunarity index, we attempt to quantify the spatial pattern in the Haikou metropolitan area. After the landscape structure changes over the periods 1986 – 96 and 1996 – 2000 are analyzed, a Markov conversion matrix is applied in order to study the sources and destinations of landscape dynamic changes. The lacunarity index is calculated in order to measure the landscape dynamics, with respect to several major land-use types, at a range of spatial scales. The findings indicate that the leapfrog development of real estate and the rapid economic growth of Haikou City have had a great impact on the dynamic landscape patterns. From 1986 to 1996 urban land expanded dramatically and clustered, while cropland was encroached upon and fragmented. From 1996 to 2000, after the government had implemented the strict cropland protection measures, urban expansion and cropland misuse were controlled to a large degree, and a lot of cropland was reclaimed in certain areas. We investigate the dynamic landscape pattern and process, and their implications in policy and economic development.

The Comparison and Modeling of the Driving Factors of Urban Expansion for Thirty-Five Big Cities in the Three Regions in China

This paper presents a national- and regional-scale urban growth model (NRUGM) of China based on panel data analysis. Through the panel analysis, population growth, road construction, salary increment per capita, and secondary industry product increment were proven to be the major driving factors for national-scale urban expansion. According to Seventh Five-Year Plan, China had been divided into three regions, Eastern China, Middle China, and Western China, by their geographic position and economic development. We studied the relationship between urban expansion and the driving factors for the three regions between 1990 and 2010 in China. The driving factors of urban expansion were different for the different regions and periods. Population growth and road construction were identified as the two major factors driving urban expansion for Eastern China. Secondary industry and economic development had become the major driving factors for urban expansion over the last twenty years in Middle China. Over the same period, for Western China, economic growth had become the major driving factor for urban expansion. Our results have significant policy implications for China. The macrocontrol of the central government should utilize different policies to adjust urban expansion in the different regions

Spatial Variability and Ecological Effects of Anthropogenic Activities in a Nature Reserve: A Case Study in the Baijitan National Nature Reserve, China

Nature reserves play an essential role in protecting natural resources and maintaining an ecological balance. However, certain nature reserves are increasingly disturbed by human activities in the form of settlements, roads, farmland, etc. How to monitor the status of nature reserves by using remote sensing methods has been a focus of scholars for a long time. In this study, remote sensing satellite images from 2009 and 2014 were used to extract and analyze the distribution of anthropogenic activities, such as agriculture, industry, residency, traffic, and other human activities. On this basis, the Nature Reserve Human Interference (NRHI) and landscape indices (LI) were calculated to describe the intensity of anthropogenic disturbance; in addition, the slope and aspect were analyzed to describe the regularity in the distribution of anthropogenic activities. The results showed that more than 90% of the anthropogenic activity occurred in the experimental and buffer zones. Likewise, the NRHI increased from 0.0901 in 2009 to 0.1127 in 2014. The NRHI was proportional to the patch density (PD), landscape shape index (LSI), landscape division index (DIVISION), Shannon’s diversity index (SHDI), and Shannon′s evenness index (SHEI), and it was inversely proportional to the contagion index (CONTAG). Moreover, 84.54% of the anthropogenic activity occurred in a range from 0 to 3.6 degrees, and 14.44% of the activity occurred in a range from 3.6 to 7.2 degrees. More than 60% of the anthropogenic activity occurred on sunny slopes because of the human adaptability to the environment and the possibility for humans to fulfill their physical needs (warmth and comfort). Thus, the monitoring of this nature reserve needs to be further strengthened and focused on the area with a range of 0–7.2 degrees and on the sunny slopes

Roles of Aquaporins in Plant-Pathogen Interaction

Aquaporins (AQPs) are a class of small, membrane channel proteins present in a wide range of organisms. In addition to water, AQPs can facilitate the efficient and selective flux of various small solutes involved in numerous essential processes across membranes. A growing body of evidence now shows that AQPs are important regulators of plant-pathogen interaction, which ultimately lead to either plant immunity or pathogen pathogenicity. In plants, AQPs can mediate H(2)O(2)transport across plasma membranes (PMs) and contribute to the activation of plant defenses by inducing pathogen-associated molecular pattern (PAMP)-triggered immunity and systemic acquired resistance (SAR), followed by downstream defense reactions. This involves the activation of conserved mitogen-activated protein kinase (MAPK) signaling cascades, the production of callose, the activation ofNPR1andPRgenes, as well as the opening and closing of stomata. On the other hand, pathogens utilize aquaporins to mediate reactive oxygen species (ROS) signaling and regulate their normal growth, development, secondary or specialized metabolite production and pathogenicity. This review focuses on the roles of AQPs in plant immunity, pathogenicity, and communications during plant-pathogen interaction

The modes of action of epsilon-polylysine (epsilon-PL) against Botrytis cinerea in jujube fruit

Epsilon-polylysine (epsilon-PL) is a natural antimicrobial and has been widely used as a food preservative. Previous studies showed epsilon-PL being effective for control of foodborne bacteria; however, little is known about its control effects on postharvest pathogenic fungi and the possible modes of action. Here, we found that epsilon-PL could significantly inhibit mycelial growth, spore germination and germ tube elongation of Botrytis cinerea in vitro, as well as effectively control gray mold in harvested jujube fruit. Further investigation indicates that the modes of action of epsilon-PL against B. cinerea include (i) stimulating the accumulation of intracellular reactive oxygen species (ROS) and reducing the expression of pathogenesis-related genes of the pathogen, (ii) resulting in the leakage of soluble carbohydrates and nucleic acids, as well as the damage of plasma membrane integrity of the fungal cells, (iii) inducing the expression of respiratory burst oxidase homolog (RBOH) genes in epsilon-PL-treated jujube fruit