Whole Sky Infrared Remote Sensing of Cloud

AbstractClouds are important factors in weather and climate change. Cloud amount, type and height are measured by means of both visual observation on ground and satellites ever before. In recent years, instruments of measuring clouds on ground have been developed. This paper introduces our progress on ground based whole sky infrared remote sensing of cloud. Some results are given. A method for determining clear sky radiance threshold was suggested, and cloud identification combined threshold method with texture method was discussed. An algorithm retrieving cloud base height from downwelling infrared radiance was suggested. Cloud classification of ground based whole sky cloud images was discussed. Structural features are better than texture features in classifying clouds

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Multiple solutions and bifurcation of nonhomogeneou

Extreme points and rotundity of Orlicz-Sobolev spaces

It is well known that Sobolev spaces have played essential roles in solving nonlinear partial differential equations. Orlicz-Sobolev spaces are generalized from Sobolev spaces. In this paper, we present sufficient and necessary conditions of extreme points of Orlicz-Sobolev spaces. A sufficient and necessary condition of rotundity of Orlicz-Sobolev spaces is obtained

Multiplexed Promoter Engineering for Improving Thaxtomin A Production in Heterologous Streptomyces Hosts

Thaxtomin A is a potent bioherbicide in both organic and conventional agriculture; however, its low yield hinders its wide application. Here, we report the direct cloning and heterologous expression of the thaxtomin A gene cluster in three well-characterized Streptomyces hosts. Then, we present an efficient, markerless and multiplex large gene cluster editing method based on in vitro CRISPR/Cas9 digestion and yeast homologous recombination. With this method, we successfully engineered the thaxtomin A cluster by simultaneously replacing the native promoters of the txtED operon, txtABH operon and txtC gene with strong constitutive promoters, and the yield of thaxtomin A improved to 289.5 µg/mL in heterologous Streptomyces coelicolor M1154. To further optimize the biosynthetic pathway, we used constraint-based combinatorial design to build 27 refactored gene clusters by varying the promoter strength of every operon, and the highest titer of thaxtomin A production reached 504.6 μg/mL. Taken altogether, this work puts forward a multiplexed promoter engineering strategy to engineer secondary metabolism gene clusters for efficiently improving fermentation titers

An Analysis of the Physical Characteristics of the Summer Low Atmosphere in the Gobi Desert Adjacent to Bosten Lake, Xinjiang, China

A month-long field observation campaign was conducted, which covered approximately 100 km2 of the Gobi Desert area on the southeast bank of Bosten Lake during the summer of 2016. The purpose of the study was to examine the physical characteristics of the low atmosphere over land-lake nonuniform underlying surfaces in the Gobi Desert of northwestern China. The results of the statistical analysis showed that, during the observational period, the average daytime surface horizontal thermal gradient reached up to −0.2°C/km from the lakeshore to southern Gobi Desert area. The near-surface wind field of the 7 km horizontal extent from the lakeshore was dominated by onshore breezes with average peak wind speeds above 5 m/s. In the atmospheric near-surface layer, an isohumidity layer at a height between 10 and 50 m a.g.l. was observed from 11:00 to 18:00 LST. Also, a case study for the atmospheric boundary layer and local circulation analyses was conducted. The onshore breezes were found to play a major role in the vertical structure of the local atmospheric boundary layer. The numerical simulation results indicated that there was an alternating day-night local circulation in the Bosten Lake area

A flexible, modular and versatile functional part assembly toolkit for gene cluster engineering in Streptomyces

Streptomyces has enormous potential to produce novel natural products (NPs) as it harbors a huge reservoir of uncharacterized and silent natural product biosynthetic gene clusters (BGCs). However, the lack of efficient gene cluster engineering strategies has hampered the pace of new drug discovery. Here, we developed an easy-to-use, highly flexible DNA assembly toolkit for gene cluster engineering. The DNA assembly toolkit is compatible with various DNA assembling approaches including Biobrick, Golden Gate, CATCH, yeast homologous recombination-based DNA assembly and homing endonuclease-mediated assembly. This compatibility offers great flexibility in handling multiple genetic parts or refactoring large gene clusters. To demonstrate the utility of this toolkit, we quantified a library of modular regulatory parts, and engineered a gene cluster (act) using characterized promoters that led to increased production. Overall, this work provides a powerful part assembly toolkit that can be used for natural product discovery and optimization in Streptomyces