168 research outputs found
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Predicting taxonomic and functional structure of microbial communities in acid mine drainage.
Predicting the dynamics of community composition and functional attributes responding to environmental changes is an essential goal in community ecology but remains a major challenge, particularly in microbial ecology. Here, by targeting a model system with low species richness, we explore the spatial distribution of taxonomic and functional structure of 40 acid mine drainage (AMD) microbial communities across Southeast China profiled by 16S ribosomal RNA pyrosequencing and a comprehensive microarray (GeoChip). Similar environmentally dependent patterns of dominant microbial lineages and key functional genes were observed regardless of the large-scale geographical isolation. Functional and phylogenetic β-diversities were significantly correlated, whereas functional metabolic potentials were strongly influenced by environmental conditions and community taxonomic structure. Using advanced modeling approaches based on artificial neural networks, we successfully predicted the taxonomic and functional dynamics with significantly higher prediction accuracies of metabolic potentials (average Bray-Curtis similarity 87.8) as compared with relative microbial abundances (similarity 66.8), implying that natural AMD microbial assemblages may be better predicted at the functional genes level rather than at taxonomic level. Furthermore, relative metabolic potentials of genes involved in many key ecological functions (for example, nitrogen and phosphate utilization, metals resistance and stress response) were extrapolated to increase under more acidic and metal-rich conditions, indicating a critical strategy of stress adaptation in these extraordinary communities. Collectively, our findings indicate that natural selection rather than geographic distance has a more crucial role in shaping the taxonomic and functional patterns of AMD microbial community that readily predicted by modeling methods and suggest that the model-based approach is essential to better understand natural acidophilic microbial communities
Non-Destructive Assessment of Stone Heritage Weathering Types Based on Machine Learning Method Using Hyperspectral Data
Stone cultural heritage is exposed to various environments, resulting in a diverse range of weathering types. The identification of these weathering types is vital for targeted conservation efforts. In this paper, a weathering type classification method based on hyperspectral imaging technology is proposed. Firstly, fresh sandstones are collected from Yungang Grottoes to carry out the simulated weathering experiments, including freeze-thaw cycles and wet-dry cycles with acid, alkali and salt solutions. Subsequently, the hyperspectral imaging system was used to collect the visible-near-infrared (VNIR) and short-wave infrared (SWIR) images of the sandstone samples with different weathering types and degrees. The surface spectral reflectance of sandstone samples with different weathering types were used as training data, with weathering types serving as the labels. Support vector machine (SVM), K-nearest neighbour (KNN), linear discriminant analysis (LDA) and random forest (RF) were used to establish weathering type classification models. The results show that the SVM model and LDA model based on both VNIR and SWIR spectra exhibit outstanding performance, with a best accuracy of 0.994. The framework proposed in this paper facilitates rapid and non-contact assessment of the weathering types of the superficial layers of stone cultural heritage, thereby supporting more targeted conservation work
Anchor3DLane: Learning to Regress 3D Anchors for Monocular 3D Lane Detection
Monocular 3D lane detection is a challenging task due to its lack of depth
information. A popular solution is to first transform the front-viewed (FV)
images or features into the bird-eye-view (BEV) space with inverse perspective
mapping (IPM) and detect lanes from BEV features. However, the reliance of IPM
on flat ground assumption and loss of context information make it inaccurate to
restore 3D information from BEV representations. An attempt has been made to
get rid of BEV and predict 3D lanes from FV representations directly, while it
still underperforms other BEV-based methods given its lack of structured
representation for 3D lanes. In this paper, we define 3D lane anchors in the 3D
space and propose a BEV-free method named Anchor3DLane to predict 3D lanes
directly from FV representations. 3D lane anchors are projected to the FV
features to extract their features which contain both good structural and
context information to make accurate predictions. In addition, we also develop
a global optimization method that makes use of the equal-width property between
lanes to reduce the lateral error of predictions. Extensive experiments on
three popular 3D lane detection benchmarks show that our Anchor3DLane
outperforms previous BEV-based methods and achieves state-of-the-art
performances. The code is available at:
https://github.com/tusen-ai/Anchor3DLane.Comment: Accepted by CVPR 202
The microstructure and mechanical properties of friction stir welded Ti6Al4V titanium alloy under β transus temperature
Ti6Al4V titanium alloy is friction stir welded using a W-Re rotational tool. The effects of welding speed on the microstructure, tensile strength and fracture properties of weld are investigated. At the rotational velocity of 250 r/min, the peak temperature is lower than β transus temperature, and the weld nugget is made up of fine α phase and transformed β phase. The grain size of shoulder affected zone is bigger than that of weld nugget because of low thermal conductivity of Ti6Al4V titanium alloy. By increasing the welding speed, the grain size of weld nugget, the tensile strength and the ductility of weld all are decreased
Enriching Phrases with Coupled Pixel and Object Contexts for Panoptic Narrative Grounding
Panoptic narrative grounding (PNG) aims to segment things and stuff objects
in an image described by noun phrases of a narrative caption. As a multimodal
task, an essential aspect of PNG is the visual-linguistic interaction between
image and caption. The previous two-stage method aggregates visual contexts
from offline-generated mask proposals to phrase features, which tend to be
noisy and fragmentary. The recent one-stage method aggregates only pixel
contexts from image features to phrase features, which may incur semantic
misalignment due to lacking object priors. To realize more comprehensive
visual-linguistic interaction, we propose to enrich phrases with coupled pixel
and object contexts by designing a Phrase-Pixel-Object Transformer Decoder
(PPO-TD), where both fine-grained part details and coarse-grained entity clues
are aggregated to phrase features. In addition, we also propose a PhraseObject
Contrastive Loss (POCL) to pull closer the matched phrase-object pairs and push
away unmatched ones for aggregating more precise object contexts from more
phrase-relevant object tokens. Extensive experiments on the PNG benchmark show
our method achieves new state-of-the-art performance with large margins.Comment: Accepted by IJCAI 202
Referring Image Segmentation via Cross-Modal Progressive Comprehension
Referring image segmentation aims at segmenting the foreground masks of the
entities that can well match the description given in the natural language
expression. Previous approaches tackle this problem using implicit feature
interaction and fusion between visual and linguistic modalities, but usually
fail to explore informative words of the expression to well align features from
the two modalities for accurately identifying the referred entity. In this
paper, we propose a Cross-Modal Progressive Comprehension (CMPC) module and a
Text-Guided Feature Exchange (TGFE) module to effectively address the
challenging task. Concretely, the CMPC module first employs entity and
attribute words to perceive all the related entities that might be considered
by the expression. Then, the relational words are adopted to highlight the
correct entity as well as suppress other irrelevant ones by multimodal graph
reasoning. In addition to the CMPC module, we further leverage a simple yet
effective TGFE module to integrate the reasoned multimodal features from
different levels with the guidance of textual information. In this way,
features from multi-levels could communicate with each other and be refined
based on the textual context. We conduct extensive experiments on four popular
referring segmentation benchmarks and achieve new state-of-the-art
performances.Comment: Accepted by CVPR 2020. Code is available at
https://github.com/spyflying/CMPC-Refse
Quality-of-life outcomes and unmet needs between ileal conduit and orthotopic ileal neobladder after radical cystectomy in a Chinese population: a 2-to-1 matched-pair analysis
Peri-operative outcomes. (DOCX 15 kb
Plant-microbe networks in soil are weakened by century-long use of inorganic fertilizers.
Understanding the changes in plant-microbe interactions is critically important for predicting ecosystem functioning in response to human-induced environmental changes such as nitrogen (N) addition. In this study, the effects of a century-long fertilization treatment (> 150 years) on the networks between plants and soil microbial functional communities, detected by GeoChip, in grassland were determined in the Park Grass Experiment at Rothamsted Research, UK. Our results showed that plants and soil microbes have a consistent response to long-term fertilization-both richness and diversity of plants and soil microbes are significantly decreased, as well as microbial functional genes involved in soil carbon (C), nitrogen (N) and phosphorus (P) cycling. The network-based analyses showed that long-term fertilization decreased the complexity of networks between plant and microbial functional communities in terms of node numbers, connectivity, network density and the clustering coefficient. Similarly, within the soil microbial community, the strength of microbial associations was also weakened in response to long-term fertilization. Mantel path analysis showed that soil C and N contents were the main factors affecting the network between plants and microbes. Our results indicate that century-long fertilization weakens the plant-microbe networks, which is important in improving our understanding of grassland ecosystem functions and stability under long-term agriculture management
Checklist of vascular plant species in Huangshui River Basin of Qinghai Province, China
The Huangshui River Basin is one of the most important water sources in the Qinghai Province and is of great importance for ecological protection measures, agricultural irrigation and tourism. Based on previous studies and fieldwork related to plant species in China, this study presents comprehensive data on vascular plants distributed in the Huangshui River Basin of Qinghai Province.Ethical Compliance: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.Data Access Statement: Research data supporting this publication are available from the repository at located at https://www.scidb.cn/en/anonymous/QUpuZVEz.Conflict of Interest declaration: The authors declare that they have NO affiliations with or involvement in any organisation or entity with any financial interest in the subject matter or materials discussed in this manuscript.The checklist of plants includes ferns, gymnosperms and angiosperms, covering three phyla, five classes, 49 orders, 139 families, 709 genera and 2,382 species. It includes numerous Asteraceae, Gramineae, Rosaceae and Fabaceae along with statistical data on the number of species distributed in different regions. The dataset presented in this article provides important background information on vascular plants in the Huangshui River Basin and, therefore, plays a crucial role in the protection and management of plant resources in this region
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GxcM-Fbp17/RacC-WASP signaling regulates polarized cortex assembly in migrating cells via Arp2/3
The actin-rich cortex plays a fundamental role in many cellular processes. Its architecture and molecular composition vary across cell types and physiological states. The full complement of actin assembly factors driving cortex formation and how their activities are spatiotemporally regulated remain to be fully elucidated. Using Dictyostelium as a model for polarized and rapidly migrating cells, we show that GxcM, a RhoGEF localized specifically in the rear of migrating cells, functions together with F-BAR protein Fbp17, a small GTPase RacC, and the actin nucleation-promoting factor WASP to coordinately promote Arp2/3 complex-mediated cortical actin assembly. Overactivation of this signaling cascade leads to excessive actin polymerization in the rear cortex, whereas its disruption causes defects in cortical integrity and function. Therefore, apart from its well-defined role in the formation of the protrusions at the cell front, the Arp2/3 complex-based actin carries out a previously unappreciated function in building the rear cortical subcompartment in rapidly migrating cells
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