925 research outputs found
Selection of waterlogging-tolerant and water purification herbaceous plants for the construction of a sponge city in Shenzhen, China
In recent years, seeking solutions to urban waterlogging and water pollution has always been one of the topics of concern. The problem of urban water accumulation occurs frequently in most areas of China in July and August. The contradiction between supply and demand of urban ecological water is prominent. In order to solve the problem of urban water accumulation caused by rainfall concentration, and to achieve the overall goal of building a water-saving green ecological city, the Shenzhen City should be built into a sponge city. Under this background, the physiological response of different forages to waterlogging stress and the removal of pollutants in rainwater were studied. In this study, ten herbaceous plants commonly used in Shenzhen were used as experimental materials. After 0, 7, 14, 21, 28 days of waterlogging stress treatment, six physiological indexes, such as MDA, SP, and Pro contents and SOD, POD, and CAT activities, were comprehensively evaluated. Combined with the morphological changes of the plants after waterlogging, seven plants with strong waterlogging tolerance were determined, which were O. bodinieri, H. coronarium, I. tectorum, D. ensifolia, R. brittoniana, C. indica, and A. zerumbet. Then, according to their comprehensive evaluation of the removal capacity of pollutants in the rainwater, it is suggested to select O. bodinieri, H. coronarium, I. tectorum and D. ensifolia in areas with serious waterlogging. In areas with serious water pollution, R. brittoniana, A. zerumbet, D. ensifolia and H. coronarium are recommended. However, H. coronarium and D. ensifolia not only have a strong adaptability in the waterlogged environment, but also have a strong ability to remove pollutants in the rainwater, so they are suggested to be alternative herbaceous plants for sponge city in Shenzhen, China
Magnetosome Gene Duplication as an Important Driver in the Evolution of Magnetotaxis in the Alphaproteobacteria
The evolution of microbial magnetoreception (or magnetotaxis) is of great interest in the fields of microbiology, evolutionary biology, biophysics, geomicrobiology, and geochemistry. Current genomic data from magnetotactic bacteria (MTB), the only prokaryotes known to be capable of sensing the Earth’s geomagnetic field, suggests an ancient origin of magnetotaxis in the domain Bacteria. Vertical inheritance, followed by multiple independent magnetosome gene cluster loss, is considered to be one of the major forces that drove the evolution of magnetotaxis at or above the class or phylum level, although the evolutionary trajectories at lower taxonomic ranks (e.g., within the class level) remain largely unstudied. Here we report the isolation, cultivation, and sequencing of a novel magnetotactic spirillum belonging to the genus Terasakiella (Terasakiella sp. strain SH-1) within the class Alphaproteobacteria. The complete genome sequence of Terasakiella sp. strain SH-1 revealed an unexpected duplication event of magnetosome genes within the mamAB operon, a group of genes essential for magnetosome biomineralization and magnetotaxis. Intriguingly, further comparative genomic analysis suggests that the duplication of mamAB genes is a common feature in the genomes of alphaproteobacterial MTB. Taken together, with the additional finding that gene duplication appears to have also occurred in some magnetotactic members of the Deltaproteobacteria, our results indicate that gene duplication plays an important role in the evolution of magnetotaxis in the Alphaproteobacteria and perhaps the domain Bacteria
Time-resolved boson sampling with photons of different colors
Interference of multiple photons via a linear-optical network has profound
applications for quantum foundation, quantum metrology and quantum computation.
Particularly, a boson sampling experiment with a moderate number of photons
becomes intractable even for the most powerful classical computers, and will
lead to "quantum supremacy". Scaling up from small-scale experiments requires
highly indistinguishable single photons, which may be prohibited for many
physical systems. Here we experimentally demonstrate a time-resolved version of
boson sampling by using photons not overlapping in their frequency spectra from
three atomic-ensemble quantum memories. Time-resolved measurement enables us to
observe nonclassical multiphoton correlation landscapes. An average fidelity
over several interferometer configurations is measured to be 0.936(13), which
is mainly limited by high-order events. Symmetries in the landscapes are
identified to reflect symmetries of the optical network. Our work thus provides
a route towards quantum supremacy with distinguishable photons.Comment: 5 pages, 3 figures, 1 tabl
Cross-lingual part-of-speech tagging using word embedding
As one of semi-supervised learning approach, cross-lingual projection leverages existing resources from a resource-rich language when building tools for resource-poor languages. In this paper we attempt to make use of word embedding with anchor based label propagation to improve the accuracy of a cross-lingual projection task: cross-lingual part-of-speech tagging under the graph-based framework. Our approach uses bilingual parallel corpora and labeled data from the resource-rich side assuming that there is no labeled data or only a few labeled data in resource-poor language. The results suggest the efficacy of our approach over traditional label propagation with lexical feature for projecting part-of-speech information across languages, and show that a few of labeled data help to enhance the effect a lot in cross-lingual task
Cancer stem cell subsets and their relationships
Emerging evidence suggests that cancer stem cells account for the initiation and progression of cancer. While many types of cancer stem cells with specific markers have been isolated and identified, a variety of differences among them began to be appreciated. Cancer stem cells are hierarchical populations that consist of precancerous stem cells, primary cancer stem cells, migrating cancer stem cells and chemoradioresistant cancer stem cells, playing different roles in cancer initiation and progression. Here we propose a new concept "horizontal hierarchy of cancer stem cells" to distinguish them from vertical hierarchy cancer stem cells, cancer transient-amplifying cells and cancer differentiated cells, and summarize our current understanding of these subsets of cancer stem cells with the aim to open up novel therapeutic strategies for cancer based on this understanding
Accumulation Pattern of Flavonoids in Cabernet Sauvignon Grapes Grown in a Low-Latitude and High-Altitude Region
Particular climate conditions in a low-latitude and high-altitude region endow grape berries with distinctivequality characteristics. So far, few reports have been concerned with the formation of berry flavour in such aregion. This study aimed to investigate the accumulation pattern of flavonoids in Vitis vinifera L. cv. CabernetSauvignon grape berries growing at different altitudes of the highland in southwest China in two consecutivevintages. In addition to the 3-O-monoglucosides and 3-O-acyl monoglucosides of the five main anthocyanidins(delphinidin, cyanidin, peonidin, petunidin and malvidin), some uncommon anthocyanins, such as threediglucosides of anthocyanidins and pelargonidin-3-O-glucoside, were detected in the grape berries. Higheraltitude cultivation greatly promoted the production of anthocyanins and flavonols, particularly cyanidintypeanthocyanins and quercetin-type flavonols from the F3’H branch of the flavonoid biosynthetic pathway.Flavan-3-ols from both branches were comparatively less influenced by vineyard altitude. Vintage in thishigh-altitude region also had a dramatic influence on the accumulation of flavonoids. Most of the anthocyaninand flavonol components were affected more by vineyard altitude than by vintage, whereas the accumulationof flavan-3-ols differed mainly between vintages. The present data will not only improve the understandingof flavonoid accumulation in grapes from a high-altitude region with different climates, but also providepractical guidance for the production of high-quality grapes and wine
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