Improving the precision of measurements is a significant scientific challenge. Previous works suggest that in a photon-coupling scenario the quantum fisher information shows a quantum-enhanced ...scaling of N
, which in theory allows a better-than-classical scaling in practical measurements. In this work, utilizing mixed states with a large uncertainty and a post-selection of an additional pure system, we present a scheme to extract this amount of quantum fisher information and experimentally attain a practical Heisenberg scaling. We performed a measurement of a single-photon's Kerr non-linearity with a Heisenberg scaling, where an ultra-small Kerr phase of ≃6 × 10
rad was observed with a precision of ≃3.6 × 10
rad. From the use of mixed states, the upper bound of quantum fisher information is improved to 2N
. Moreover, by using an imaginary weak-value the scheme is robust to noise originating from the self-phase modulation.
Photosynthetic bacteria are beneficial to plants, but knowledge of photosynthetic bacterial community dynamics in field crops during different growth stages is scarce. The factors controlling the ...changes in the photosynthetic bacterial community during plant growth require further investigation. In this study, 35 microbial community samples were collected from the seedling, flowering, and mature stages of tomato, cucumber, and soybean plants. 35 microbial community samples were assessed using Illumina sequencing of the photosynthetic reaction center subunit M (pufM) gene. The results revealed significant alpha diversity and community structure differences among the three crops at the different growth stages. Proteobacteria was the dominant bacterial phylum, and Methylobacterium, Roseateles, and Thiorhodococcus were the dominant genera at all growth stages. PCoA revealed clear differences in the structure of the microbial populations isolated from leaf samples collected from different crops at different growth stages. In addition, a dissimilarity test revealed significant differences in the photosynthetic bacterial community among crops and growth stages (P<0.05). The photosynthetic bacterial communities changed during crop growth. OTUs assigned to Methylobacterium were present in varying abundances among different sample types, which we speculated was related to the function of different Methylobacterium species in promoting plant growth development and enhancing plant photosynthetic efficiency. In conclusion, the dynamics observed in this study provide new research ideas for the detailed assessments of the relationship between photosynthetic bacteria and different growth stages of plants.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The intelligentisation of coal mines is the only approach to the high‐quality development of the coal industry. Detection, identification and sorting of coal gangue is an important part of the ...intelligentisation of coal mines. Focusing on various problems in coal gangue detecting and recognising algorithms, such as limited receptive field, slow convergence rate and low accuracy of small particle recognition, this paper proposes a coal gangue detection and recognition algorithm based on deformable convolution YOLOv3 (DCN‐YOLOv3). To improve the accuracy of anchor frame positioning and enhance the diversity of the dataset, the deformed convolution YOLOv3 network model is established based on the detection algorithm YOLOv3, using deformable convolution, multiple k‐means clustering results average method and data enhancement technology as means. The model was trained through the self‐designed dataset, and the algorithm's correctness and accuracy for coal gangue recognition under different size and illumination conditions are verified. The test results showed that the algorithm effectively detects and recognises coal gangue, improves the accuracy and efficiency of detecting and recognising small‐size coal and gangue and improves environmental robustness. Furthermore, compared with the traditional recognition algorithm, the network convergence speed of this algorithm is significantly improved, the mAP is increased to 99.45%, and the maximum FLOPs value is reduced by 61.4%. Accordingly, this research is considered to be of certain theoretical value and technical reference for identifying coal gangue.
With the picolinyl (Pic) group as a C‐1 located directing group and N3 as versatile precursor for C5‐NH2, a novel 1‐Pic‐5‐N3 thiosialyl donor was designed and synthesized, based on which a new ...sialylation protocol was established. In comparison to conventional sialylation methods, the new protocol exhibited obvious advantages, including excellent α‐stereoselectivity in the absence of a solvent effect, broad substrate scope encompassing the challenging sialyl 8‐ and 9‐hydroxy groups of sialic acid acceptors, flexibility in sialoside derivative synthesis, high temperature tolerance and easy scalability. In particular, the applicability to the synthesis of complex and bioactive N‐glycan antennae when combined with the MPEP glycosylation protocol via the “latent‐active” strategy has been shown. Mechanistically, the excellent α‐stereoselectivity of the novel sialylation protocol could be attributed to the dramatic electron‐withdrawing effect of the protonated Pic groups, which was supported by control reactions and DFT calculations.
Sugar building blocks: With 1‐Picolinyl‐5‐azido thiosialoside as donor, a robust sialylation was developed that is applicable to the flexible synthesis of complex sialosides and shows broad substrate scope, good to excellent chemical yield, excellent α‐stereoselectivity, high temperature tolerance, and easy scalability.
Tomato chlorosis virus (ToCV) is widespread, seriously impacting tomato production throughout the world. ToCV is semi-persistently transmitted by
(Gennadius) (Hemiptera: Aleyrodidae). Currently, ...insect olfaction is being studied to develop novel pest control technologies to effectively control
and whitefly-borne virus diseases. Despite current research efforts, no report has been published on the role of odorant-binding proteins (OBPs) in insect preference under the influence of plant virus. Our previous research showed that viruliferous
preferred healthy plants at 48 h after virus acquisition. In this study, we determined the effect of OBPs on the host preference interactions of ToCV and whiteflies. Our results show that with the increase in acquisition time, the OBP gene expressions changed differently, and the
gene expression showed a trend of first rising and then falling, and reached the maximum at 48 h. These results indicate that
may participate in the host preference of viruliferous whiteflies to healthy plants. When the expression of the
gene was knocked down by an RNA interference (RNAi) technique, viruliferous Mediterranean (MED) showed no preference and the ToCV transmission rate was reduced by 83.3%. We conclude that
is involved in the detection of plant volatiles by viruliferous MED. Our results provide a theoretical basis and technical support for clarifying the transmission mechanism of ToCV by
and could provide new avenues for controlling this plant virus and its vectors.
In existing quantum key distribution protocols, two legitimate peers, Alice and Bob, must monitor the signal disturbance to place a bound on the potential information leakage. However, in the ...round-robin differential phase shift (RRDPS) protocol, monitoring of the signal disturbance is unnecessary. Here, we present the first active implementation of the RRDPS protocol. In our experiment, Alice prepares packets of pulses, where each packet is a train with 65 pulses and the global phase of each packet is randomized. Bob uses a novel actively controlled variable-delay interferometer to realize the random switching of different delays. Benefiting from the large pulse number of each packet, and the high stability and low insertion loss of the interferometer, the system can distribute a secret key over a distance of 90 km. Our experimental demonstration and results confirm the feasibility of the RRDPS protocol, particularly in high-error situations.
Heavy metal migration in soil poses a serious threat to the soil and groundwater. Understanding the migration pattern of heavy metals (HMs) under different factors could provide a more reasonable ...position for pollution evaluation and targetoriented treatment of soil heavy metal. In this study, the migration behavior of Pb and Cd in co-contaminated soil under different pH and ionic strength (NaCl concentration) was simulated using convective dispersion equation (CDE). We predicted the migration trends of Pb and Cd in soils after 5, 10, and 20 years via PHREEQC. The results showed that the migration time of Cd in the soil column experiment was about 60 days faster than that of Pb, and the migration trend was much steeper. The CDE was proved to describe the migration behavior of Pb and Cd (R2 > 0.75) in soil. The predicted results showed that Cd migrated to 15–20 cm of soil within 7 years and Pb stayed mainly in the top 0–6 cm of soil within 5 years as the duration of irrigation increased. Overall, our study is expected to provide new insight into the migration of heavy metal in soil ecosystems and guidance for reducing risk of heavy metal in the environment.
Display omitted
•The CDE model could be applied to actual composite contaminated soils via experiments and multi-parameter simulation.•Cd was a greater threat to groundwater and deep soil than Pb in co-contaminated soils.•The CDE model revealed the spatial evolution of pollutants at regional scale and could be extended at a large scale region.•The amount of soil contamination remediation materials could be quantified via the contamination cube of HMs.
A wide area quantum key distribution (QKD) network deployed on communication infrastructures provided by China Mobile Ltd. is demonstrated. Three cities and two metropolitan area QKD networks were ...linked up to form the Hefei-Chaohu-Wuhu wide area QKD network with over 150 kilometers coverage area, in which Hefei metropolitan area QKD network was a typical full-mesh core network to offer all-to-all interconnections, and Wuhu metropolitan area QKD network was a representative quantum access network with point-to-multipoint configuration. The whole wide area QKD network ran for more than 5000 hours, from 21 December 2011 to 19 July 2012, and part of the network stopped until last December. To adapt to the complex and volatile field environment, the Faraday-Michelson QKD system with several stability measures was adopted when we designed QKD devices. Through standardized design of QKD devices, resolution of symmetry problem of QKD devices, and seamless switching in dynamic QKD network, we realized the effective integration between point-to-point QKD techniques and networking schemes.
PDF
