Sea-Surface Object Detection Based on Electro-Optical Sensors: A Review

Sea-surface object detection is critical for navigation safety of autonomous ships. Electrooptical (EO) sensors, such as video cameras, complement radar on board in detecting small obstacle sea-surface objects. Traditionally, researchers have used horizon detection, background subtraction, and foreground segmentation techniques to detect sea-surface objects. Recently, deep learning-based object detection technologies have been gradually applied to sea-surface object detection. This article demonstrates a comprehensive overview of sea-surface object-detection approaches where the advantages and drawbacks of each technique are compared, covering four essential aspects: EO sensors and image types, traditional object-detection methods, deep learning methods, and maritime datasets collection. In particular, sea-surface object detections based on deep learning methods are thoroughly analyzed and compared with highly influential public datasets introduced as benchmarks to verify the effectiveness of these approaches. The arti

Multi-Scale Object Detection Model for Autonomous Ship Navigation in Maritime Environment

Accurate detection of sea-surface objects is vital for the safe navigation of autonomous ships. With the continuous development of artificial intelligence, electro-optical (EO) sensors such as video cameras are used to supplement marine radar to improve the detection of objects that produce weak radar signals and small sizes. In this study, we propose an enhanced convolutional neural network (CNN) named VarifocalNet * that improves object detection in harsh maritime environments. Specifically, the feature representation and learning ability of the VarifocalNet model are improved by using a deformable convolution module, redesigning the loss function, introducing a soft non-maximum suppression algorithm, and incorporating multi-scale prediction methods. These strategies improve the accuracy and reliability of our CNN-based detection results under complex sea conditions, such as in turbulent waves, sea fog, and water reflection. Experimental results under different maritime conditions show that our method significantly outperforms similar methods (such as SSD, YOLOv3, RetinaNet, Faster R-CNN, Cascade R-CNN) in terms of the detection accuracy and robustness for small objects. The maritime obstacle detection results were obtained under harsh imaging conditions to demonstrate the performance of our network model

Investigation of Salt Tolerance Mechanisms across a Root Developmental Gradient in Almond Rootstocks

The intensive use of groundwater in agriculture under the current climate conditions leads to acceleration of soil salinization. Given that almond is a salt-sensitive crop, selection of salt-tolerant rootstocks can help maintain productivity under salinity stress. Selection for tolerant rootstocks at an early growth stage can reduce the investment of time and resources. However, salinity-sensitive markers and salinity tolerance mechanisms of almond species to assist this selection process are largely unknown. We established a microscopy-based approach to investigate mechanisms of stress tolerance in and identified cellular, root anatomical, and molecular traits associated with rootstocks exhibiting salt tolerance. We characterized three almond rootstocks: Empyrean-1 (E1), Controller-5 (C5), and Krymsk-86 (K86). Based on cellular and molecular evidence, our results show that E1 has a higher capacity for salt exclusion by a combination of upregulating ion transporter expression and enhanced deposition of suberin and lignin in the root apoplastic barriers, exodermis, and endodermis, in response to salt stress. Expression analyses revealed differential regulation of cation transporters, stress signaling, and biopolymer synthesis genes in the different rootstocks. This foundational study reveals the mechanisms of salinity tolerance in almond rootstocks from cellular and structural perspectives across a root developmental gradient and provides insights for future screens targeting stress response

First international external quality assessment scheme of nucleic acid amplification tests for the detection of Schistosoma and soil-transmitted helminths, including Strongyloides : a pilot study

Background Nucleic acid amplification tests (NAATs) are increasingly being used as diagnostic tools for soil-transmitted helminths (STHs;Ascaris lumbricoides,Trichuris trichiura,Necator americanus,Ancylostoma duodenaleandA.ceylanicum),Strongyloides stercoralisandSchistosomain human stool. Currently, there is a large diversity of NAATs being applied, but an external quality assessment scheme (EQAS) for these diagnostics is lacking. An EQAS involves a blinded process where test results reported by a laboratory are compared to those reported by reference or expert laboratories, allowing for an objective assessment of the diagnostic performance of a laboratory. In the current study, we piloted an international EQAS for these helminths (i) to investigate the feasibility of designing and delivering an EQAS; (ii) to assess the diagnostic performance of laboratories; and (iii) to gain insights into the different NAAT protocols used. Methods and principal findings A panel of twelve stool samples and eight DNA samples was validated by six expert laboratories for the presence of six helminths (Ascaris,Trichuris,N.americanus,Ancylostoma,StrongyloidesandSchistosoma). Subsequently this panel was sent to 15 globally dispersed laboratories. We found a high degree of diversity among the different DNA extraction and NAAT protocols. Although most laboratories performed well, we could clearly identify the laboratories that were poorly performing. Conclusions/Significance We showed the technical feasibility of an international EQAS for the NAAT of STHs,StrongyloidesandSchistosoma. In addition, we documented that there are clear benefits for participating laboratories, as they can confirm and/or improve the diagnostic performance of their NAATs. Further research should aim to identify factors that explain poor performance of NAATs. Author summary Tests that detect parasite DNA in human stool are increasingly being used for the diagnosis of infections with intestinal worms, including schistosomiasis. To ensure the quality in diagnostic testing of these parasitic worms, it is important that laboratories evaluate the diagnostic performance of their DNA-based tests. This can best be achieved by participating in an external quality assessment scheme (EQAS). An EQAS involves a blinded process where test results reported by a laboratory are compared to those reported by reference or expert laboratories, allowing for an objective assessment of the diagnostic performance of a laboratory. Currently, such an EQAS for parasitic worms is lacking. We therefore piloted an international EQAS for the diagnosis of parasitic worms involving 15 laboratories in Africa, Asia, Australia, Europe, and North America. Although most laboratories performed well, we could clearly identify those laboratories that may need to improve their test protocol. We found that laboratories were using many different test protocols, and further research should aim to verify whether this has an impact on the performance of the diagnostic outcomes

Liposome-based transfection enhances RNAi and CRISPR-1 mediated mutagenesis in non-model nematode systems

Nematodes belong to one of the most diverse animal phyla. However, functional genomic studies in nematodes, other than in a few species, have often been limited in their reliability and success. Here we report that by combining liposome-based technology with microinjection, we were able to establish a wide range of genomic techniques in the newly described nematode genus Auanema. The method also allowed heritable changes in dauer larvae of Auanema, despite the immaturity of the gonad at the time of the microinjection. As proof of concept for potential functional studies in other nematode species, we also induced RNAi in the free-living nematode Pristionchus pacificus and targeted the human parasite Strongyloides stercoralis

Evolution and Horizontal Transfer of a DD37E DNA Transposon in Mosquitoes

ITmD37E, a unique class II transposable element (TE) with an ancient origin, appears to have been involved in multiple horizontal transfers in mosquitoes as ITmD37E sequences from 10 mosquito species of five genera share high nucleotide (nt) identities. For example, ITmD37E sequences from Aedes aegypti and Anopheles gambiae, which have an estimated common ancestor of 145–200 million years ago, display 92% nt identity. The comparison of ITmD37E and host mosquito phylogenies shows a lack of congruence. The wide distribution of conserved ITmD37Es in mosquitoes and the presence of intact copies suggest that this element may have been recently active

Tungsten distribution in soil and rice in the vicinity of the world's largest and longest-operating tungsten mine in China.

The objective of this study is to investigate tungsten (W) contamination in soil and its enrichment in rice in the area of the world's largest and longest-operating W mines in China. Root zone soil and rice plants were sampled at 15 sites in the agricultural field adjacent to W mines and analyzed for Al, Fe, Mn, Sc, and W contents and W chemical forms in the soil samples and W contents in the rice root, stem, leaf, and grain samples. Results showed that W content in the soil ranged from 3.99 to 43.7 mg kg(-1), with more than 90% of W in the residual fraction, showing its low mobility and bioavailability. Average W contents in the rice root, stem, leaf, and grain were 7.06, 2.34, 4.76, 0.17 mg kg(-1), respectively. In addition, they were linearly independent of W content and chemical forms in the soil. Average enrichment factor values were 0.39, 0.13, 0.28, and 0.01 for the root, stem, leaf, and grain, respectively. In can be concluded that W mining activity in the Dayu county contaminated the nearby agricultural soil and led to W bioaccumulation in the rice. This may pose a health risk to residents via food and soil ingestion, which should be a focus of scrutiny

Realizing Mussel-Inspired Polydopamine Selective Layer with Strong Solvent Resistance in Nanofiltration toward Sustainable Reclamation

Herein, a mussel-inspired polydopamine (PDA) coating layer has been first explored as a separating layer for organic solvent nanofiltration (OSN). A PDA based separating layer was constructed on polyimide (PI) support via dopamine coating. The subsequent membrane was then treated with 1,6-hexanediamine for cross-linking on both the PDA layer and PI support. Fourier transform infrared (ATR-FTIR) and X-ray photoelectron (XPS) results indicated the deposition of PDA on support and the cross-linked structures of both PDA and PI. Scanning electron microscopy (SEM), atomic force microscopy (AFM), water contact angle, and surface energy measurements were further employed to characterize the morphologies and surface properties of the composite membranes. After an optimized coating time of 4 h, the resultant membrane showed an EtOH permeance of 0.91 L m^–2 h^–1 bar^–1 and a RB rejection of 99%. More importantly, the composite membrane also exhibited good performance for dyes separation from a wide range of solvents including challenging polar aprotic and strongly swelling solvents, such as dimethylformamide and acetone. In addition to demonstrating a facile and effective OSN membrane fabrication approach, this study may stimulate the bioinspired design of a composite membrane for sustainable applications

Effect of Different Boron Fertilizer Supply Patterns and Levels on Growth, Development and Quality of Flue-Cured Tobacco

Boron, one of the essential trace elements for normal growth and development of tobacco, has a great impact on the yield and quality of flue-cured tobacco. The objective of this study is to explore the best pattern and level of boron fertilizer supply of red soil in the Honghe tobacco area. In this study, the randomized block design was used to study different boron fertilizer supply methods and levels. The results showed that during transplanting, it was good to apply 1.50 kg/ha Fertibor boron with pure boron content≥15%; at the resettling stage, it was good to spray 225 kg solution composed of 75 mL/ha Compo liquid boron with pure boron content≥130g/L mixed with water onto leaves when night fell in a sunny day. The two fertilization methods had better effect than the basal application of boron fertilizer, and the resistance to pests and diseases or economic character of tobacco plants was better than under spraying treatment