1,415 research outputs found
Roles of soil pores in determining water retention and microbial dynamics
Soil pore provides an essential habitat for microbial communities to participate in various biogeochemical processes. The complex pore spaces, which are defined by the arrangement of particles of varying sizes, govern the distribution of water for microbial dispersal and movement and microbial interaction with one another, such as bacterial cell-to-cell and bacterium-virus interactions. This research focused on exploring how soil pores influence soil water retention and bacterial interactions and quantify the spatial distribution of bacteria and viruses in fine-scale of soil pores. Using a mathematical model, this study simulated a soil water retention curve based on the relationship between soil pores and water retention characteristics. A fractional bulk density (FBD) concept was proposed in the model to estimate pore water content under varying matric potential. Comparing the estimated results of the water retention curve with the measured data, the model behaved overall well. The proposed model provides an easy way to evaluate the impacts of soil pores on water conservation in soils. Based on the concept in the FBD model, sand media with different pore sizes coupled with different surface properties were used to evaluate conjugation-based bacterial cell-to-cell interactions. The presence of sand increased conjugation frequency compared to sand-free controls. The frequencies were a function of pore size and bacterial adhesion on sand surfaces with smaller pores and more adhesion lowering bacterial conjugation frequency. Collision of bacteria in pore spaces promoted their interactions, while limited motility of bacteria trapped in smaller pores or adhered to sand surfaces reduced the interactions. To further investigate microbial activity in fine-scale pores, the spatial distribution of bacteria and viruses in soil was characterized by using advanced small-angle X-ray/neutron scattering techniques. Bacteria and viruses have their optimal strategies for survival in soil pores in response to soil harsh environments. Bacteria preferred to colonize in the pores greatly close to their sizes and viruses aggregated to prevent penetrating into nanopores. These observations highlighted soil pore-associated water and microbial dynamics and advance the understanding of the functions of soil pores in soil ecosystems
A Translation Study of Cultural Vacancy in the book To Live under the Guidance of Relevance Translation Theory
The cultural vacancy refers to the cultural information carried in one language that has no counterpart in another language. Cultural vacancies are common in the book To Live, and the quality of its translation affects foreign readersā understanding and acceptance of the distinctive Chinese culture. In this paper, the author sorts out the version of To Live translated by Michael Berry on the Internet, and studies the English translation methods of its cultural vacancies guided by Relevance Translation Theory, including literal translation, free translation, and transliteration with annotations, in order to improve the translation quality of To Live, to accurately convey the meaning of the original text of To Live to foreign readers, to promote the exchange and dissemination of To Live written by Yu Hua and other excellent Chinese novels in the world, and improve Chinaās cultural soft power
Minimalist and High-Performance Semantic Segmentation with Plain Vision Transformers
In the wake of Masked Image Modeling (MIM), a diverse range of plain,
non-hierarchical Vision Transformer (ViT) models have been pre-trained with
extensive datasets, offering new paradigms and significant potential for
semantic segmentation. Current state-of-the-art systems incorporate numerous
inductive biases and employ cumbersome decoders. Building upon the original
motivations of plain ViTs, which are simplicity and generality, we explore
high-performance `minimalist' systems to this end. Our primary purpose is to
provide simple and efficient baselines for practical semantic segmentation with
plain ViTs. Specifically, we first explore the feasibility and methodology for
achieving high-performance semantic segmentation using the last feature map. As
a result, we introduce the PlainSeg, a model comprising only three 33
convolutions in addition to the transformer layers (either encoder or decoder).
In this process, we offer insights into two underlying principles: (i)
high-resolution features are crucial to high performance in spite of employing
simple up-sampling techniques and (ii) the slim transformer decoder requires a
much larger learning rate than the wide transformer decoder. On this basis, we
further present the PlainSeg-Hier, which allows for the utilization of
hierarchical features. Extensive experiments on four popular benchmarks
demonstrate the high performance and efficiency of our methods. They can also
serve as powerful tools for assessing the transfer ability of base models in
semantic segmentation. Code is available at
\url{https://github.com/ydhongHIT/PlainSeg}
A Facile Synthetic Method for Anhydride from Carboxylic Acid with the Promotion of Triphenylphosphine Oxide and Oxaloyl Chloride
A highly efficient synthesis reaction of carboxylic anhydrides catalyzed by triphenylphosphine oxide is described for the quick synthesis of a range of symmetric carboxylic anhydrides and cyclic anhydrides under mild and neutral conditions with a high yield. The system adopts the strong reactive intermediate Ph3PCl2 as the catalyst of carboxylic acid salt; driven by catalytic reaction, the synthesis takes a relatively short time to complete
Representation Separation for Semantic Segmentation with Vision Transformers
Vision transformers (ViTs) encoding an image as a sequence of patches bring
new paradigms for semantic segmentation.We present an efficient framework of
representation separation in local-patch level and global-region level for
semantic segmentation with ViTs. It is targeted for the peculiar
over-smoothness of ViTs in semantic segmentation, and therefore differs from
current popular paradigms of context modeling and most existing related methods
reinforcing the advantage of attention. We first deliver the decoupled
two-pathway network in which another pathway enhances and passes down
local-patch discrepancy complementary to global representations of
transformers. We then propose the spatially adaptive separation module to
obtain more separate deep representations and the discriminative
cross-attention which yields more discriminative region representations through
novel auxiliary supervisions. The proposed methods achieve some impressive
results: 1) incorporated with large-scale plain ViTs, our methods achieve new
state-of-the-art performances on five widely used benchmarks; 2) using masked
pre-trained plain ViTs, we achieve 68.9% mIoU on Pascal Context, setting a new
record; 3) pyramid ViTs integrated with the decoupled two-pathway network even
surpass the well-designed high-resolution ViTs on Cityscapes; 4) the improved
representations by our framework have favorable transferability in images with
natural corruptions. The codes will be released publicly.Comment: 17 pages, 13 figures. This work has been submitted to the IEEE for
possible publication. Copyright may be transferred without notice, after
which this version may no longer be accessibl
Hysteresis behavior of reinforced concrete bridge piers considering strength and stiffness degradation and pinching effect
In order to effectively simulate the nonlinear hysteresis behavior of reinforced concrete (RC) bridge piers under strong earthquake excitation, an improved nonlinear hysteresis model for RC bridge piers was developed and its controlling parameters were determined considering stiffness and strength degradation and pinching effect based on classical Bouc-Wen model. The improved model can be carried out to predict the nonlinear hysteresis behavior of RC bridge piers under various failure modes using MATLAB/ Simulink program. Cyclic tests of different failure mode bridge column specimens were performed under constant axial load with lateral bending. The results did show that force-displacement relationship curves of bridge column specimens derived from theoretical analysis agree well with experimental results. The nonlinear hysteresis behavior of bridge column specimen was simulated under 2008 Wenchuan earthquake excitation and its failure modes were identical with real earthquake damage of bridge column. The improved analytical models in the paper were applied to accurately predicting the nonlinear hysteresis behavior of RC bridge columns with strength and stiffness degradations and the pinching effect subjected to strong earthquake motion
Flow Injection Chemiluminescent Immunoassay for Carcinoembryonic Antigen Using Boronic Immunoaffinity Column
A flow injection chemiluminescence immunoassay for rapid and sensitive detection of carcinoembryonic antigen (CEA) by using a phenylboronic acid-based immunoaffinity column as a glycoprotein collector was proposed in this paper. The column was prepared by coupling of 3-aminophenylboronic acid on the glass beads through a Ī³-glycidoxypropyltrimethoxysilane (GPMS) linkage. Based on an indirect competitive immunoreaction, the mixture of CEA sample and enzyme conjugated CEA antibody (HRP-anti-CEA) was incubated in advance, followed by direct injection to the column to capture free HRP-labeled CEA antibody in the column. The trapped HRP-labeled antibody was detected by flow inject chemiluminescence in the presence of luminol and hydrogen peroxide. The decreased chemiluminescent signal was proportional to the concentration of CEA in the range of 3.0ā30.0 ng/mL with a correlation coefficient of 0.998. The column showed an acceptable reproducibility and stability and is potentially used for practical clinical detection of the serum CEA level
Neurogenesis Potential Evaluation and Transcriptome Analysis of Fetal Hypothalamic Neural Stem/Progenitor Cells With Prenatal High Estradiol Exposure
High maternal estradiol is reported to induce metabolic disorders by modulating hypothalamic gene expression in offspring. Since neurogenesis plays a crucial role during hypothalamus development, we explored whether prenatal high estradiol exposure (HE) affects proliferation and differentiation of fetal hypothalamic neural stem/progenitor cells (NSC/NPCs) in mice and performed RNA sequencing to identify the critical genes involved. NSC/NPCs in HE mice presented attenuated cell proliferation but increased neuronal differentiation in vitro compared with control (NC) cells. Gene set enrichment analysis of mRNA profiles indicated that genes downregulated in HE NSC/NPCs were enriched in neurogenesis-related Gene Ontology (GO) terms, while genes upregulated in HE NSC/NPCs were enriched in response to estradiol. Protein-protein interaction analysis of genes with core enrichment in GO terms of neurogenesis and response to estradiol identified 10 Hub mRNAs, among which three were potentially correlated with six differentially expressed (DE) lncRNAs based on lncRNA profiling and co-expression analysis. These findings offer important insights into developmental modifications in hypothalamic NSC/NPCs and may provide new clues for further investigation on maternal environment programmed neural development disorders
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