Functional evaluation of pollutant transformation in sediment from combined sewer system

© 2018 Elsevier Ltd In this study, a pilot combined sewer system was constructed to characterize the pollutant transformation in sewer sediment. The results showed that particulate contaminants deposited from sewage could be transformed into dissolved matter by distinct pollutant transformation pathways. Although the oxidation-reduction potential (ORP) was varied from −80 mV to −340 mV in different region of the sediment, the fermentation was the dominant process in all regions of the sediment, which induced hydrolysis and decomposition of particulate contaminants. As a result, the accumulation of dissolved organic matter and the variation of ORP values along the sediment depth led to the depth-dependent reproduction characteristics of methanogens and sulfate-reducing bacteria, which were existed in the middle and deep layer of the sediment respectively. However, the diversity of nitrifying and polyphosphate-accumulating bacteria was low in sewer sediment and those microbial communities showed a non-significant correlation with nitrogen and phosphorus contaminants, which indicated that the enrichment of nitrogen and phosphorus contaminants was mainly caused by physical deposition process. Thus, this study proposed a promising pathway to evaluate pollutant transformation and can help provide theoretical foundation for urban sewer improvement

Synthetically Supervised Feature Learning for Scene Text Recognition

We address the problem of image feature learning for scene text recognition. The image features in the state-of-the-art methods are learned from large-scale synthetic image datasets. However, most meth- ods only rely on outputs of the synthetic data generation process, namely realistically looking images, and completely ignore the rest of the process. We propose to leverage the parameters that lead to the output images to improve image feature learning. Specifically, for every image out of the data generation process, we obtain the associated parameters and render another “clean” image that is free of select distortion factors that are ap- plied to the output image. Because of the absence of distortion factors, the clean image tends to be easier to recognize than the original image which can serve as supervision. We design a multi-task network with an encoder-discriminator-generator architecture to guide the feature of the original image toward that of the clean image. The experiments show that our method significantly outperforms the state-of-the-art methods on standard scene text recognition benchmarks in the lexicon-free cate- gory. Furthermore, we show that without explicit handling, our method works on challenging cases where input images contain severe geometric distortion, such as text on a curved path

Architecture of Pol II(G) and molecular mechanism of transcription regulation by Gdown1.

Tight binding of Gdown1 represses RNA polymerase II (Pol II) function in a manner that is reversed by Mediator, but the structural basis of these processes is unclear. Although Gdown1 is intrinsically disordered, its Pol II interacting domains were localized and shown to occlude transcription factor IIF (TFIIF) and transcription factor IIB (TFIIB) binding by perfect positioning on their Pol II interaction sites. Robust binding of Gdown1 to Pol II is established by cooperative interactions of a strong Pol II binding region and two weaker binding modulatory regions, thus providing a mechanism both for tight Pol II binding and transcription inhibition and for its reversal. In support of a physiological function for Gdown1 in transcription repression, Gdown1 co-localizes with Pol II in transcriptionally silent nuclei of early Drosophila embryos but re-localizes to the cytoplasm during zygotic genome activation. Our study reveals a self-inactivation through Gdown1 binding as a unique mode of repression in Pol II function

Transformation and utilization of slowly biodegradable organic matters in biological sewage treatment of anaerobic anoxic oxic systems

© 2016 Elsevier Ltd. This study examined the distribution of carbon sources in two anaerobic anoxic oxic (AAO) sewage treatment plants in Xi'an and investigated the transformation characteristics and utilization potential of slowly biodegradable organic matters (SBOM). Results indicated under anaerobic and aerobic conditions, SBOM could be transformed at a rate of 65% in 8 h into more readily biologically utilizable substrates such as volatile fatty acids (VFAs), polysaccharides and proteins. Additionally, non-biodegradable humus-type substances which are difficult to biodegrade and readily accumulate, were also generated. These products could be further hydrolyzed to aldehyde and ketone compounds and then transformed into substances with significant oxygen-containing functional groups and utilized subsequently. The molecular weights of proteinoid substances had a wide distribution and tended to decrease over time. Long hours of microbial reaction increased the proportion of micromolecular substances. This particular increase generated significant bioavailability, which can greatly improve the efficiency of nitrogen removal

Determining the global scale size of chorus waves in the magnetosphere

Chorus waves outside the plasmapause influence the Earth's radiation belt dynamics by interacting with energetic electrons via cyclotron and Landau resonance. Recent numerical diffusion experiments indicate that the diffusion process is sensitive to the spatial and temporal scale of variability in the wave-particle interaction, which is reported to be more efficient than that based on the traditional average model. Using Van Allen Probes A and B data from November 2012 to July 2019, the spatial and temporal scale size of chorus waves are calculated by the correlation between the wave amplitudes detected by two satellites with varying spatial separation or time lag. We found that, the chorus wave is incoherent when the spatial extent is greater than 433 km or the time lag lasts ∼10 s, which are significantly smaller than that of plasmaspheric hiss. In addition, the spatial correlations of chorus tend to be higher near noon or with lower geomagnetic activity. The temporal correlations of chorus are always statistically near zero, which are not influenced by the location and geomagnetic activity. Our results can help refine the model of the interactions between energetic particles and chorus waves in the radiation belt

Recent changes of water discharge and sediment load in the Yellow River basin, China

The Yellow River basin contributes approximately 6% of the sediment load from all river systems globally, and the annual runoff directly supports 12% of the Chinese population. As a result, describing and understanding recent variations of water discharge and sediment load under global change scenarios are of considerable importance. The present study considers the annual hydrologic series of the water discharge and sediment load of the Yellow River basin obtained from 15 gauging stations (10 mainstream, 5 tributaries). The Mann-Kendall test method was adopted to detect both gradual and abrupt change of hydrological series since the 1950s. With the exception of the area draining to the Upper Tangnaihai station, results indicate that both water discharge and sediment load have decreased significantly (p<0.05). The declining trend is greater with distance downstream, and drainage area has a significant positive effect on the rate of decline. It is suggested that the abrupt change of the water discharge from the late 1980s to the early 1990s arose from human extraction, and that the abrupt change in sediment load was linked to disturbance from reservoir construction.Geography, PhysicalGeosciences, MultidisciplinarySCI(E)43ARTICLE4541-5613

Modelling low velocity impact induced damage in composite laminates

The paper presents recent progress on modelling low velocity impact induced damage in fibre reinforced composite laminates. It is important to understand the mechanisms of barely visible impact damage (BVID) and how it affects structural performance. To reduce labour intensive testing, the development of finite element (FE) techniques for simulating impact damage becomes essential and recent effort by the composites research community is reviewed in this work. The FE predicted damage initiation and propagation can be validated by Non Destructive Techniques (NDT) that gives confidence to the developed numerical damage models. A reliable damage simulation can assist the design process to optimise laminate configurations, reduce weight and improve performance of components and structures used in aircraft construction

Modelling low velocity impact induced damage in composite laminates

The paper presents recent progress on modelling low velocity impact induced damage in fibre reinforced composite laminates. It is important to understand the mechanisms of barely visible impact damage (BVID) and how it affects structural performance. To reduce labour intensive testing, the development of finite element (FE) techniques for simulating impact damage becomes essential and recent effort by the composites research community is reviewed in this work. The FE predicted damage initiation and propagation can be validated by Non Destructive Techniques (NDT) that gives confidence to the developed numerical damage models. A reliable damage simulation can assist the design process to optimise laminate configurations, reduce weight and improve performance of components and structures used in aircraft construction

Counter-current chromatography for the separation of terpenoids: A comprehensive review with respect to the solvent systems employed

Copyright @ 2014 The Authors.This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.Natural products extracts are commonly highly complex mixtures of active compounds and consequently their purification becomes a particularly challenging task. The development of a purification protocol to extract a single active component from the many hundreds that are often present in the mixture is something that can take months or even years to achieve, thus it is important for the natural product chemist to have, at their disposal, a broad range of diverse purification techniques. Counter-current chromatography (CCC) is one such separation technique utilising two immiscible phases, one as the stationary phase (retained in a spinning coil by centrifugal forces) and the second as the mobile phase. The method benefits from a number of advantages when compared with the more traditional liquid-solid separation methods, such as no irreversible adsorption, total recovery of the injected sample, minimal tailing of peaks, low risk of sample denaturation, the ability to accept particulates, and a low solvent consumption. The selection of an appropriate two-phase solvent system is critical to the running of CCC since this is both the mobile and the stationary phase of the system. However, this is also by far the most time consuming aspect of the technique and the one that most inhibits its general take-up. In recent years, numerous natural product purifications have been published using CCC from almost every country across the globe. Many of these papers are devoted to terpenoids-one of the most diverse groups. Naturally occurring terpenoids provide opportunities to discover new drugs but many of them are available at very low levels in nature and a huge number of them still remain unexplored. The collective knowledge on performing successful CCC separations of terpenoids has been gathered and reviewed by the authors, in order to create a comprehensive document that will be of great assistance in performing future purifications. © 2014 The Author(s)

Observation of CR Anisotropy with ARGO-YBJ

The measurement of the anisotropies of cosmic ray arrival direction provides important informations on the propagation mechanisms and on the identification of their sources. In this paper we report the observation of anisotropy regions at different angular scales. In particular, the observation of a possible anisotropy on scales between $\sim$ 10 $^{\circ}$ and $\sim$ 30 $^{\circ}$ suggests the presence of unknown features of the magnetic fields the charged cosmic rays propagate through, as well as potential contributions of nearby sources to the total flux of cosmic rays. Evidence of new weaker few-degree excesses throughout the sky region $195^{\circ}\leq$ R.A. $\leq 315^{\circ}$ is reported for the first time.Comment: Talk given at 12th TAUP Conference 2011, 5-9 September 2011, Munich, German