To improve the effectiveness of limited spectral resources, an adaptive orthogonal frequency division multiplexing integrated radar and communications waveform design method is proposed. First, the ...conditional mutual information (MI) between the random target impulse response and the received signal, and the data information rate (DIR) of frequency selective fading channel are formulated. Then, with the constraint on the total power, the optimization problem, which simultaneously considers the conditional MI for radar and DIR for communications, is devised, and the analytic solution is derived. With low transmit power, the designed integrated waveform outperforms the fixed waveform (i.e., equal power allocation). Finally, several simulated experiments are provided to verify the effectiveness of the designed waveform.
A novel synthetic approach toward 1,4‐disubstituted 1,2,3‐triazoles by CN‐ and NN‐bond formation has been established under transition‐metal‐free conditions. Complete control of the ...regioselectivity was successfully achieved. Commercially available anilines, ketones, and N‐tosylhydrazine were treated with molecular iodine in one pot to allow the regioselective generation of 1,4‐disubstituted 1,2,3‐triazoles in high yields without the use of azides.
A novel synthetic approach toward 1,4‐disubstituted 1,2,3‐triazoles by CN‐ and NN‐bond formation has been established under transition‐metal‐free conditions (see scheme). Complete control of regioselectivity was successfully achieved and anilines, ketones, and N‐tosylhydrazines were treated with molecular iodine in one pot to allow the formation of 1,4‐disubstitued 1,2,3‐triazoles in high yields without the use of azides.
The 2019 positive Indian Ocean Dipole (IOD) was the strongest event since the 1960s which developed independently without coinciding El Niño. The dynamics is not fully understood. Here we show that ...in March–May, westward propagating oceanic Rossby waves, a remnant consequence of the weak 2018 Pacific warm condition, led to anomalous sea surface temperature warming in the southwest tropical Indian Ocean (TIO), inducing deep convection and anomalous easterly winds along the equator, which triggered the initial cooling in the east. In June–August, the easterly wind anomalies continued to evolve through ocean‐atmosphere coupling involving Bjerknes feedback and equatorial nonlinear ocean advection, until its maturity in September–November. This study clarifies the contribution of oceanic Rossby waves in the south TIO in different dynamic settings and reveals a new triggering mechanism for extreme IOD events that will help to understand IOD diversity.
Plain Language Summary
The Indian Ocean Dipole (IOD) is an ocean‐atmosphere coupled climatic phenomenon which can cause severe social and economic losses in the surrounding regions such as drought in the Maritime Continent/Australia and flooding in East Africa. The IOD features a see‐saw structure accompanied by an anomalous sea surface temperature gradient, winds, and oceanic adjustments. The El Niño–Southern Oscillation in the Pacific is an important trigger to a strong IOD event. However, an extreme positive IOD event occurred in 2019 without a concurrent or ensuing El Niño. We show that the thermocline warming associated with anomalous ocean downwelling in the southwest tropical Indian Ocean triggered atmospheric convection, inducing anomalous easterly winds along the equator and hence, positive feedbacks associated with an IOD event. This study may help to understand the evolution of extreme IOD and improve IOD predictability.
Key Points
The oceanic downwelling Rossby waves in the south tropical Indian Ocean is key to the 2019 extreme positive Indian Ocean Dipole (IOD)
The Rossby waves induced thermocline warming, triggering wind‐evaporation‐SST feedback thus anomalous easterly winds along the equator
The easterly wind anomalies further triggered the Bjerknes feedback and other positive feedbacks and established an extreme IOD
The first example of oxidant-free cobalt-catalyzed synthesis of five-membered spirocycles is reported from benzimidates and maleimides utilizing nitrobenzene as promoter. In contrast to previously ...known cobalt-catalyzed oxidative C–H functionalization reactions, this transformation occurs efficiently in the absence of oxidant and is accompanied by liberation of hydrogen. The spiro-lactams were readily achieved by the hydrolysis of as-prepared spirocyclic compounds. The Cp*Rh(III) catalyst shows poor reactivity.
The direct thiolation of arenes and alkenes with diaryl disulfides was developed by nickel catalysis. The reaction displayed exceptional compatibility with a wide range of functional groups to ...regioselectively give the diaryl sulfides and alkenyl sulfides in high yields.
Salt substitutes with reduced sodium levels and increased potassium levels have been shown to lower blood pressure, but their effects on cardiovascular and safety outcomes are uncertain.
We conducted ...an open-label, cluster-randomized trial involving persons from 600 villages in rural China. The participants had a history of stroke or were 60 years of age or older and had high blood pressure. The villages were randomly assigned in a 1:1 ratio to the intervention group, in which the participants used a salt substitute (75% sodium chloride and 25% potassium chloride by mass), or to the control group, in which the participants continued to use regular salt (100% sodium chloride). The primary outcome was stroke, the secondary outcomes were major adverse cardiovascular events and death from any cause, and the safety outcome was clinical hyperkalemia.
A total of 20,995 persons were enrolled in the trial. The mean age of the participants was 65.4 years, and 49.5% were female, 72.6% had a history of stroke, and 88.4% a history of hypertension. The mean duration of follow-up was 4.74 years. The rate of stroke was lower with the salt substitute than with regular salt (29.14 events vs. 33.65 events per 1000 person-years; rate ratio, 0.86; 95% confidence interval CI, 0.77 to 0.96; P = 0.006), as were the rates of major cardiovascular events (49.09 events vs. 56.29 events per 1000 person-years; rate ratio, 0.87; 95% CI, 0.80 to 0.94; P<0.001) and death (39.28 events vs. 44.61 events per 1000 person-years; rate ratio, 0.88; 95% CI, 0.82 to 0.95; P<0.001). The rate of serious adverse events attributed to hyperkalemia was not significantly higher with the salt substitute than with regular salt (3.35 events vs. 3.30 events per 1000 person-years; rate ratio, 1.04; 95% CI, 0.80 to 1.37; P = 0.76).
Among persons who had a history of stroke or were 60 years of age or older and had high blood pressure, the rates of stroke, major cardiovascular events, and death from any cause were lower with the salt substitute than with regular salt. (Funded by the National Health and Medical Research Council of Australia; SSaSS ClinicalTrials.gov number, NCT02092090.).
In this letter, we developed novel Structure Enhanced Channel Attention Network (SECANet) for scene text image super‐resolution (STISR). The newly proposed SECANet integrates a group of ...Structure‐Enhanced Attention Modules to focus more on both local and global structural features in the character regions of text images. Moreover, we elaborately formulate a Dual‐Domain Contrastive Learning framework that integrates one pixel‐level contrastive loss and the other semantic‐level contrastive loss to jointly optimize the SECANet for generating more visually pleasing yet better recognizable high‐quality SR images without introducing any additional prior generators in both the training and testing stages, showing promising computational efficiency. Experimental results on the Textzoom dataset indicate that our method can achieve both decent performance in super‐resolving more impressive scene text images from low‐resolution ones and better recognition accuracy than other competitors.
The proposed structure enhanced channel attention network assembles a group of structure‐enhanced attention blocks to learn both global and local structure features for the detailed recovery of scene text images. Moreover, a joint dual‐domain contrastive loss function is formulated to optimize the model parameters, benefiting to synthesizing more recognizable text images.
The morphological analysis and volume measurement of the hippocampus are crucial to the study of many brain diseases. Therefore, an accurate hippocampal segmentation method is beneficial for the ...development of clinical research in brain diseases. U-Net and its variants have become prevalent in hippocampus segmentation of Magnetic Resonance Imaging (MRI) due to their effectiveness, and the architecture based on Transformer has also received some attention. However, some existing methods focus too much on the shape and volume of the hippocampus rather than its spatial information, and the extracted information is independent of each other, ignoring the correlation between local and global features. In addition, many methods cannot be effectively applied to practical medical image segmentation due to many parameters and high computational complexity. To this end, we combined the advantages of CNNs and ViTs (Vision Transformer) and proposed a simple and lightweight model: Light3DHS for the segmentation of the 3D hippocampus. In order to obtain richer local contextual features, the encoder first utilizes a multi-scale convolutional attention module (MCA) to learn the spatial information of the hippocampus. Considering the importance of local features and global semantics for 3D segmentation, we used a lightweight ViT to learn high-level features of scale invariance and further fuse local-to-global representation. To evaluate the effectiveness of encoder feature representation, we designed three decoders of different complexity to generate segmentation maps. Experiments on three common hippocampal datasets demonstrate that the network achieves more accurate hippocampus segmentation with fewer parameters. Light3DHS performs better than other state-of-the-art algorithms.
•A lightweight network called Light3DHS is proposed for 3D hippocampus segmentation.•Light3DHS effectively combines the characteristics of CNN and Transformer paradigms.•Light3DHS utilizes multi-scale attention to fuse features from local to global.•Results from the decoders demonstrate the effectiveness of encoder.•Light3DHS can deeply understand and precisely segment 3D hippocampus.
NNNifty targets: In a straightforward copper‐mediated synthesis of 1,4‐disubstituted and 1,4,5‐trisubstituted 1,2,3‐triazoles, readily available aniline and N‐tosylhydrazone substrates underwent ...cyclization through CN and NN bond formation (see scheme; Piv=pivaloyl, Ts=p‐toluenesulfonyl). This method enables the preparation of 1,2,3‐triazoles with high efficiency under mild conditions without the use of azides.
Soil salinity is a major abiotic stress that limits plant growth and agriculture productivity. To cope with salt stress, plants have evolved complex salt-responsive signaling and metabolic processes ...at the cellular, organ, and whole-plant levels. Investigation of the physiological and molecular mechanisms underlying plant salinity tolerance will provide valuable information for effective engineering strategies. Current proteomics provides a high-throughput approach to study sophisticated molecular networks in plants. In this review, we describe a salt-responsive protein database by an integrated analysis of proteomics-based studies. The database contains 2171 salt-responsive protein identities representing 561 unique proteins. These proteins have been identified from leaves, roots, shoots, seedlings, unicells, grains, hypocotyls, radicles, and panicles from 34 plant species. The identified proteins provide invaluable information toward understanding the complex and fine-tuned plant salt-tolerance mechanisms in photosynthesis, reactive oxygen species (ROS) scavenging, ion homeostasis, osmotic modulation, signaling transduction, transcription, protein synthesis/turnover, cytoskeleton dynamics, and cross-tolerance to different stress conditions.
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