Anaerobic sequencing batch reactor (SBR) was started-up by inoculating the nitrifying activated sludge. After an operation of 72 d, the bioreactor reached at steady state with ammonia and nitrite removal percentages higher than 95%. During operation, the sludge granulated in the reactor. The morphology and internal structure of sludge granules changed conspicuously, the density increased while the color changed from khaki to red. The average granular diameter grew from 1.2 to 3.69 mm, and its settling velocity accelerated from 107.68 to 118.49 m/h. Sludge granulation improved the tolerance to hydraulic shock loading, and reduced sludge washout (TSS < 0.028 g/L). The dominant bacterial communities (filamentous and cocci) in nitrifying activated sludge were replaced by irregular shaped ANAMMOX bacterial species gradually. An increase of ANAMMOX rate was achieved with the increasing granular diameter. SBR is a useful reactor to cultivate ANAMMOX granular sludge, while granular ANAMMOX sludge thus developed can be used as seeding sludge in a pilot-scale or full scale wastewater treatment plant.
The mucus-associated symbionts have profound impacts on the pathogen defense, metabolism, and development of aquatic animals. To understand the microbial structure of regional endothermic fish, a total of 52 samples from the skin, oral, gill, and hindgut of wild tuna Thunnus albacares and T. obesus were determined by 16S amplicon sequencing. The results showed the diversity and composition of microbial communities varied in the four different body sites of tunas, with a greater heterogeneity between the external surface and the gut. Phyla Proteobacteria, Firmicutes, Actinobacteria and genus Acinetobacter were found in high relative abundance in all body sites. The other abundant taxa were enriched in different body sites, such as Lactobacillus and Kocuria in the skin and Geobacillus in the gut. The core taxa interacted with each other to different degrees in the four body sites, which may be related to species’ co-evolution and microbial community stability. Finally, the correlation between biomarkers and COG functions highlighted the importance of microbial biomarkers to the host. This work firstly characterized the microbial feature in different body sites of wild tunas, providing a foundational dataset to understand the microbial role in endothermic fish and to find key microbial components beneficial to farmed tunas.
Music content has recently been identified as useful information to promote the performance of music recommendations. Existing studies usually feed low-level audio features, such as the Mel-frequency cepstral coefficients, into deep learning models for music recommendations. However, such features cannot well characterize music audios, which often contain multiple sound sources. In this paper, we propose to model and fuse chord, melody, and rhythm features to meaningfully characterize the music so as to improve the music recommendation. Specially, we use two user-based attention mechanisms to differentiate the importance of different parts of audio features and chord features. In addition, a Long Short-Term Memory layer is used to capture the sequence characteristics. Those features are fused by a multilayer perceptron and then used to make recommendations. We conducted experiments with a subset of the last.fm-1b dataset. The experimental results show that our proposal outperforms the best baseline by [Formula: see text] on HR@10.
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