Towards visible soliton microcomb generation

Frequency combs have applications that extend from the ultra-violet into the mid-infrared bands. Microcombs, a miniature and often semiconductor-chip-based device, can potentially access most of these applications, but are currently more limited in spectral reach. Here, we demonstrate mode-locked silica microcombs with emission near the edge of the visible spectrum. By using both geometrical and mode-hybridization dispersion control, devices are engineered for soliton generation while also maintaining optical Q factors as high as 80 million. Electronics-bandwidth-compatible (20 GHz) soliton mode locking is achieved with low pumping powers (parametric oscillation threshold powers as low as 5.4 mW). These are the shortest wavelength soliton microcombs demonstrated to date and could be used in miniature optical clocks. The results should also extend to visible and potentially ultra-violet bands

Symmetrical Linguistic Feature Distillation with CLIP for Scene Text Recognition

In this paper, we explore the potential of the Contrastive Language-Image Pretraining (CLIP) model in scene text recognition (STR), and establish a novel Symmetrical Linguistic Feature Distillation framework (named CLIP-OCR) to leverage both visual and linguistic knowledge in CLIP. Different from previous CLIP-based methods mainly considering feature generalization on visual encoding, we propose a symmetrical distillation strategy (SDS) that further captures the linguistic knowledge in the CLIP text encoder. By cascading the CLIP image encoder with the reversed CLIP text encoder, a symmetrical structure is built with an image-to-text feature flow that covers not only visual but also linguistic information for distillation.Benefiting from the natural alignment in CLIP, such guidance flow provides a progressive optimization objective from vision to language, which can supervise the STR feature forwarding process layer-by-layer.Besides, a new Linguistic Consistency Loss (LCL) is proposed to enhance the linguistic capability by considering second-order statistics during the optimization. Overall, CLIP-OCR is the first to design a smooth transition between image and text for the STR task.Extensive experiments demonstrate the effectiveness of CLIP-OCR with 93.8% average accuracy on six popular STR benchmarks.Code will be available at https://github.com/wzx99/CLIPOCR.Comment: Accepted by ACM MM 202

Self-Supervised Pre-training with Symmetric Superimposition Modeling for Scene Text Recognition

In text recognition, self-supervised pre-training emerges as a good solution to reduce dependence on expansive annotated real data. Previous studies primarily focus on local visual representation by leveraging mask image modeling or sequence contrastive learning. However, they omit modeling the linguistic information in text images, which is crucial for recognizing text. To simultaneously capture local character features and linguistic information in visual space, we propose Symmetric Superimposition Modeling (SSM). The objective of SSM is to reconstruct the direction-specific pixel and feature signals from the symmetrically superimposed input. Specifically, we add the original image with its inverted views to create the symmetrically superimposed inputs. At the pixel level, we reconstruct the original and inverted images to capture character shapes and texture-level linguistic context. At the feature level, we reconstruct the feature of the same original image and inverted image with different augmentations to model the semantic-level linguistic context and the local character discrimination. In our design, we disrupt the character shape and linguistic rules. Consequently, the dual-level reconstruction facilitates understanding character shapes and linguistic information from the perspective of visual texture and feature semantics. Experiments on various text recognition benchmarks demonstrate the effectiveness and generality of SSM, with 4.1% average performance gains and 86.6% new state-of-the-art average word accuracy on Union14M benchmarks. The code is available at https://github.com/FaltingsA/SSM.Comment: Accepted to IJCAI202

Environmental controls of harmful cyanobacterial blooms in Chinese inland waters

Harmful cyanobacterial blooms (CyanoHABs) are expanding world-wide, adversely affecting aquatic food production, recreational and tourism activities and safe drinking water supplies. China's inland waters have been increasingly threatened by CyanoHABs during the past several decades. The environmental factors controlling CyanoHABs are highly variable in space and time in China due to significant variations in climate, geography, geological and geochemical conditions among its many regions. Here, we synthesize diverse examples among Chinese water bodies regarding interactive effects of anthropogenic, climatic and geographic drivers influencing CyanoHAB potentials and dynamics in lakes and reservoirs; in order to provide a perspective and integrative approach to mitigating CyanoHABs. In China's many shallow water bodies, water quality is highly susceptible to human activity and to changing climatic and hydrological conditions, when compared to deeper lakes. Rapid increases in population, economic activity, and wastewater have accelerated CyanoHABs in China since 1980s, especially in the heavily urbanized, agricultural and industrial regions in the middle and lower Yangtze River basins. Climatic changes have provided an additional catalyst for expansion of CyanoHABs. In particular, rising spring temperatures have accelerated the onset and proliferation of Microcystis spp, blooms in the middle and lower reaches of Yangtze River basin. Large hydroelectric and water supply projects, like the Three Gorges Reservoir (TGR), have altered hydrological regimes, and have led to an increase of CyanoHABs in reservoirs and tributaries due to increases in water residence times. Manipulating water level fluctuations in the TGR may prove useful for controlling CyanoHAB in its tributary bays. Overall,CyanoHAB mitigation strategies will have to incorporate both N and P input reductions in these shallow systems. Furthermore, nutrient reduction strategies must consider climate change-induced increases in extreme weather events, including more intense rainfall and protracted heat waves and droughts, which can extend the magnitudes and duration of CyanoHABs. Ensuring the maintenance of natural hydrologic connectivity between lakes and rivers is of utmost importance in mitigating CyanoHABs throughout China

Corrigendum to “Environmental controls of harmful cyanobacterial blooms in Chinese inland waters”

Corrigendum to “Environmental controls of harmful cyanobacterial blooms in Chinese inland waters

Efficacy and safety study of ultrasound guided microwave ablation of large benign thyroid nodules

Objective To retrospectively evaluate the efficacy and safety of microwave ablation （MWA）in the treatment of large benign thyroid nodules. Methods Patients with large thyroid nodules who underwent ultrasound- guided MWA at Jiangsu Province Hospital and Jiangsu Province Official Hospital from March 2013 to October 2018 were included. A total of 191 patients with 397 nodules were enrolled. All nodules were confirmed as benign by ultrasound-guided fine-needle aspiration cytology（FNA）， with the main nodule volume＞20 mL. Intraoperative and postoperative complications were recorded. Nodule volume was assessed at 1，3，6，12，and 24 months post-treatment. Volume changes and volume reduction rate（VRR）were compared among nodules of different compositions and sizes. The correlation between ablation energy and VRR was analyzed based on nodule volume and composition.Results Over time，the VRR of all three nodule types（solid group 77 cases；cystic group 95 cases；mixed group 19 cases）progressively increased，with significant effects observed for time ，group，and their interaction（Ftime=39.288，Ptime＜0.01；Fgroup=6.177，Pgroupinteraction=4.299，Pinteraction＜0.01）. When stratified by volume［（20-30 mL group（95 cases）； ＞30-40 mL group（45 cases）；＞40 mL group（51 cases）］，significant effects were also found for time，group，and interaction（Ftime= 159.085，Ptime ＜0.01；Fgroup=34.861，Pgroup ＜0.01；Finteraction= 10.323，Pinteraction ＜0.01）. Correlation analysis showed that both total microwave energy and energy per unit volume were negatively correlated with VRR at 24 months（PConclusion MWA is a safe and effective treatment for large benign thyroid nodules. Greater cystic content and larger initial nodule volume were associated with better ablation outcomes. Ablation energy was negatively correlated with VRR