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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.

Nitrogen (N) is a major driving force for crop yield improvement, but application of high levels of N delays flowering, prolonging maturation and thus increasing the risk of yield losses. Therefore, traits that enable utilization of high levels of N without delaying maturation will be highly desirable for crop breeding. Here, we show that OsNRT1.1A (OsNPF6.3), a member of the rice (Oryza sativa) nitrate transporter 1/peptide transporter family, is involved in regulating N utilization and flowering, providing a target to produce high yield and early maturation simultaneously. OsNRT.1A has functionally diverged from previously reported NRT1.1 genes in plants and functions in upregulating the expression of N utilization-related genes not only for nitrate but also for ammonium, as well as flowering-related genes. Relative to the wild type, osnrt1.1a mutants exhibited reduced N utilization and late flowering. By contrast, overexpression of OsNRT1.1A in rice greatly improved N utilization and grain yield, and maturation time was also significantly shortened. These effects were further confirmed in different rice backgrounds and also in Arabidopsis thaliana. Our study paves a path for the use of a single gene to dramatically increase yield and shorten maturation time for crops, outcomes that promise to substantially increase world food security.

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Biogranulation is a promising biotechnology developed for wastewater treatment. Biogranules exhibit a matrix microbial structure, and intensive research has shown that extracellular polymeric substances (EPS) are a major component of the biogranule matrix material in both anaerobic and aerobic granules. This paper aims to review the role of EPS in biogranulation, factors influencing EPS production, the effect of EPS on cell surface properties of biogranules, and the relationship of EPS to the structural stability of biogranules. EPS production is substantially enhanced when the microbial community is subject to stressful culture conditions, and the stimulated EPS production in the microbial matrix in turn favours the formation of anaerobic and aerobic granules. EPS can also play an essential role in maintaining the integrity and stability of spatial structure in mature biogranules. It is expected that this paper can provide deep insights into the functions of EPS in the biogranulation process.

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A state‐of‐the‐art mesoscale atmospheric model was used to investigate the three‐dimensional structure and evolution of shallow convective clouds and precipitation in heterogeneous and homogeneous domains. In general, the spatial distribution of clouds and precipitation is strongly affected by the landscape structure. When the domain is homogeneous, they appear to be randomly distributed. However, when the landscape structure triggers the formation of mesoscale circulations, they concentrate in the originally dry part of the domain, creating a negative feedback which tends to eliminate the landscape discontinuities, and spatially homogenize the land water content. The land surface wetness heterogeneity of the domain and the toted amount of water vapor present in the atmosphere (locally evapotranspired and/or advected) affect the precipitation regime. In general, the upward motion of mesoscale circulations generated by landscape heterogeneities is stronger than thermal cells induced by turbulence. Furthermore, their ability to transport moist, warm air to higher elevations increases the amount of water that can be condensed and precipitated. The evolution of shallow convective clouds and precipitation consists of a “build‐up phase” during which turbulence is predominant and responsible for the moistening of the atmosphere. In heterogeneous domains, it is also responsible for the creation of horizontal pressure gradients leading to the generation of mesoscale circulations. This phase occurs during the morning hours. From about 1200 until 1600 LST, clouds develop and most of the precipitation is produced. This is the “active phase.” After 1600 LST, the horizontal thermal and pressure gradients, which fed the energy necessary to create and sustain the mesoscale circulations, gradually disappear. This is the “dissipation phase.” The differences and similarities obtained between three‐dimensional and two‐dimensional simulations were also studied. These simulations indicate that, unless the landscape presents a clear two‐dimensional structure, the use of such a two‐dimensional model is not appropriate to simulate this type of clouds and precipitation. Conversely, two‐dimensional simulations can be confidently used, provided that the simulated domain presents a two‐dimensional heterogeneity.