SaaFormer: Spectral-spatial Axial Aggregation Transformer for Hyperspectral Image Classification

Hyperspectral images (HSI) captured from earth observing satellites and aircraft is becoming increasingly important for applications in agriculture, environmental monitoring, mining, etc. Due to the limited available hyperspectral datasets, the pixel-wise random sampling is the most commonly used training-test dataset partition approach, which has significant overlap between samples in training and test datasets. Furthermore, our experimental observations indicates that regions with larger overlap often exhibit higher classification accuracy. Consequently, the pixel-wise random sampling approach poses a risk of data leakage. Thus, we propose a block-wise sampling method to minimize the potential for data leakage. Our experimental findings also confirm the presence of data leakage in models such as 2DCNN. Further, We propose a spectral-spatial axial aggregation transformer model, namely SaaFormer, to address the challenges associated with hyperspectral image classifier that considers HSI as long sequential three-dimensional images. The model comprises two primary components: axial aggregation attention and multi-level spectral-spatial extraction. The axial aggregation attention mechanism effectively exploits the continuity and correlation among spectral bands at each pixel position in hyperspectral images, while aggregating spatial dimension features. This enables SaaFormer to maintain high precision even under block-wise sampling. The multi-level spectral-spatial extraction structure is designed to capture the sensitivity of different material components to specific spectral bands, allowing the model to focus on a broader range of spectral details. The results on six publicly available datasets demonstrate that our model exhibits comparable performance when using random sampling, while significantly outperforming other methods when employing block-wise sampling partition.Comment: arXiv admin note: text overlap with arXiv:2107.02988 by other author

The genome evolution and domestication of tropical fruit mango

Background: Mango is one of the world’s most important tropical fruits. It belongs to the family Anacardiaceae, which includes several other economically important species, notably cashew, sumac and pistachio from other genera. Many species in this family produce family-specific urushiols and related phenols, which can induce contact dermatitis. Results: We generate a chromosome-scale genome assembly of mango, providing a reference genome for the Anacardiaceae family. Our results indicate the occurrence of a recent whole-genome duplication (WGD) event in mango. Duplicated genes preferentially retained include photosynthetic, photorespiration, and lipid metabolic genes that may have provided adaptive advantages to sharp historical decreases in atmospheric carbon dioxide and global temperatures. A notable example of an extended gene family is the chalcone synthase (CHS) family of genes, and particular genes in this family show universally higher expression in peels than in flesh, likely for the biosynthesis of urushiols and related phenols. Genome resequencing reveals two distinct groups of mango varieties, with commercial varieties clustered with India germplasms and demonstrating allelic admixture, and indigenous varieties from Southeast Asia in the second group. Landraces indigenous in China formed distinct clades, and some showed admixture in genomes. Conclusions: Analysis of chromosome-scale mango genome sequences reveals photosynthesis and lipid metabolism are preferentially retained after a recent WGD event, and expansion of CHS genes is likely associated with urushiol biosynthesis in mango. Genome resequencing clarifies two groups of mango varieties, discovers allelic admixture in commercial varieties, and shows distinct genetic background of landraces

The genome evolution and domestication of tropical fruit mango

Background: Mango is one of the world’s most important tropical fruits. It belongs to the family Anacardiaceae, which includes several other economically important species, notably cashew, sumac and pistachio from other genera. Many species in this family produce family-specific urushiols and related phenols, which can induce contact dermatitis. Results: We generate a chromosome-scale genome assembly of mango, providing a reference genome for the Anacardiaceae family. Our results indicate the occurrence of a recent whole-genome duplication (WGD) event in mango. Duplicated genes preferentially retained include photosynthetic, photorespiration, and lipid metabolic genes that may have provided adaptive advantages to sharp historical decreases in atmospheric carbon dioxide and global temperatures. A notable example of an extended gene family is the chalcone synthase (CHS) family of genes, and particular genes in this family show universally higher expression in peels than in flesh, likely for the biosynthesis of urushiols and related phenols. Genome resequencing reveals two distinct groups of mango varieties, with commercial varieties clustered with India germplasms and demonstrating allelic admixture, and indigenous varieties from Southeast Asia in the second group. Landraces indigenous in China formed distinct clades, and some showed admixture in genomes. Conclusions: Analysis of chromosome-scale mango genome sequences reveals photosynthesis and lipid metabolism are preferentially retained after a recent WGD event, and expansion of CHS genes is likely associated with urushiol biosynthesis in mango. Genome resequencing clarifies two groups of mango varieties, discovers allelic admixture in commercial varieties, and shows distinct genetic background of landraces

Control scheme for multi-terminal VSC-based medium-voltage DC distribution networks

With the development and application of voltage source converter (VSC) high voltage direct current (HVDC) technology, DC distribution is gradually attracting the attention of researchers in recent years. However, many studies are still in the theoretical and exploratory stages. Compared with DC transmission networks, medium-voltage DC (MVDC) distribution networks are more sophisticated with respect to the complex operation modes, high penetration of renewable energy resource, and use of diverse power electronic devices. Therefore, master–slave control strategy which has been widely used in HVDC transmission projects may not be the first choice for DC distribution networks. In this study, a three-terminal DC distribution dynamic simulation platform is initially established and droop control strategy is adopted due to its flexible scalability. Secondly, plug and play solutions for key equipment such as VSCs and DC solid-state transformers are proposed. Thirdly, the response characteristics of a droop control system under high renewable energy resource penetration and frequent transition of operation mode are studied. Fourthly, the system fault isolation and recovery strategy under DC pole-to-pole fault is proposed. Finally, the whole control scheme is validated through experiments using the dynamic simulation platform. In the future, this proposed scheme can be used in the control of VSC-based MVDC distribution networks

Current limiting control method with adaptive virtual impedance for grid-forming STATCOM

Current limiting is an important issue in the static synchronous compensator (STATCOM) with grid-forming (GFM) control. However, the conventional methods are difficult to deal with the application scenarios of different grid faults. In this paper, an improved current limiting method with the adaptive virtual impedance is proposed for the GFM STATCOM. The specific implementation strategy of the GFM control is introduced firstly. The generation method of the adaptive virtual impedance and the realization of current limiting strategy are also presented in detail. The proposed adaptive virtual impedance can be adjusted automatically by following voltage sag, which realizes the adaption of different grid faults situations. The proposed method is realized by the GFM STATCOM simulation platform with PSCAD/EMTDC, it is confirmed that the proposed method has a faster current limiting response speed when the voltage sag is larger, which can improve the supporting effect of GFM STATCOM for the grid voltage drop

The complete sequence of chloroplast genome from mango (Mangifera indica var GuiFei)

The common mango is known as ‘king of fruits’ and the second most important tropical fruit crop. Mango production plays an important role in the rural economy of many tropical and subtropical countries. In this study, we sequenced its circular complete chloroplast genome (cpDNA) of mango. The complete cpDNA was 157,837 bp in length and consisted of a pair of inverted repeats (IRs) of 40,428 bp, a large single copy (LSC) region of 59,717 bp, and a small single copy (SSC) region of 43,323 bp. Totally, 171 genes were predicted, including 118 protein-coding genes, 8 ribosomal RNA genes, and 45 tRNA genes. Phylogenetic analysis of all sequenced chloroplast genomes in the fruit suggested that mango was closely related to three other Citrus species. The results indicate that the chloroplast genomes are good resources for developing new DNA markers for taxonomy and also as tools for evolutionary research of closely related species in future studies

Treatment options and clinical outcomes for carbapenem-resistant Enterobacteriaceae bloodstream infection in a Chinese university hospital

Background: Carbapenem resistant Enterobacteriaceae (CRE) has become a serious public health problem. Limited information is available about the treatment options that physicians used to fight CRE infections and related clinical outcomes in China. The aim of the present study was to explore the treatment options and clinical outcomes of patients with CRE bloodstream infection (BSI) in a Chinese teaching hospital. Methods: A retrospective study was conducted during 2011 to 2015 in one Chinese teaching hospital. Demographic, microbiological and clinical characteristics of enrolled subjects were collected from medical records. Data were analyzed by Kaplan–Meier graphs, log-rank test, and Cox regression. Results: A total of 98 inpatients with CRE BSI were enrolled in this study. For empirical therapy, 26 patients (26.5%) received at least one active drug within 48 h after the onset of bacteremia. For definitive treatment, 59.2% (49/82) patients received at least one active drug and 40.2% (33/82) patients received therapy with no active drug. The overall 30-day mortality was 53.1% (52/98). Adverse outcome appeared to be more likely among patients with previous carbapenem exposure, neutropenia, severity of septic and time to initiation of BSIs. There was no significant difference in the mortality between the two groups of patients with combination therapy versus monotherapy (p = 0.105). Severity of sepsis and neutropenia were identified as independent predictors of mortality. Conclusions: Our study demonstrated a high mortality associated with CRE BSI and a high percentage of inappropriate empirical treatment for CRE BSI patients in a Chinese teaching hospital. Particular attention should be given to the patients with CRE BSI. Keywords: Carbapenem-resistant Enterobacteriaceae, Bloodstream infection, Antimicrobial therap

Defect Control and Curing Process Simulation for T700/603 Composites

The autoclave curing process of advanced grid-stiffened MT300/603 composite has been simulated based on heat-conducting/curing-reaction and resin-flowing/fiber-compaction. The fiber volume fractions and internal defects were evaluated and investigated in term of the curing temperature, brazing time, pressure applying point and molding pressure, which were used to set up the defect control and process improvement. Furthermore, the ?1 m grid stiffened cylinder was prepared to verify the availability for this process optimization method. The results show that increasing pressure and enhancing pre-bulking can significantly improve the internal quality and load-carrying ability of ?1 m specimen

Evaluation of automated systems for aminoglycosides and fluoroquinolones susceptibility testing for Carbapenem-resistant Enterobacteriaceae

Abstract Background Automated systems (MicroScan WalkAway 96 Plus, Phoenix 100, and Vitek 2 Compact) are widely used in clinical laboratories nowadays. The aim of this study is to evaluate the performance of these three systems for susceptibility testing of aminoglycosides and fluoroquinolones against Carbapenem-resistant Enterobacteriaceae (CRE). Methods A total of 75 CRE isolates were used in this study. Quinolone resistance determinants (QRDs) (qnrA, qnrB, qnrC, qnrD, qnrS, aac(6′)-Ib-cr, oqxAB and qepA) and aminoglycoside resistance determinants (ARDs) (aac(6′)-Ib, armA, npmA, rmtA, rmtB, rmtC, rmtD and rmtE) of these CRE were screened by PCR. The MICs of aminoglycosides (gentamicin and amikacin) and fluoroquinolones (ciprofloxacin and levofloxacin) to CRE obtained with the automated systems were compared with the reference method (agar dilution method). Results Totally, 97.3% (73/75) of CRE harbored QRDs. The qnr gene was the most common QRD determinant identified in 68 (96.7%), followed by aac (6′)-Ib-cr in 56 (74.7%), oqxAB in 23 (30.7%), and qepA in 2 (2.7%), respectively. 22.7% (17/75) of CRE harbored ARD determinants. rmtA, rmtB and npmA were identified among these isolates in 6 (8.0%), 6 (8.0%) and 5 (6.7%), respectively. A total of 900 results were obtained in this study. Overall, the total error rate was 9.89%. Twenty-eight very major errors (3.11%), 22 major errors (2.44%) and 39 minor errors (4.33%) were identified against agar dilution method. The very major errors were almost evenly distributed between results for fluoroquinolones (2.89%) and aminoglycosides (3.33%), while the major errors and minor errors were more commonly found in the results of fluoroquinolones (3.11% and 6.44%, respectively) than aminoglycosides (1.78% and 2.22%, respectively). Conclusions Our study shows that testing difficulties in susceptibility testing do exist in automated systems. We suggest clinical laboratories using automated systems should consider using a second, independent antimicrobial susceptibility testing method to validate aminoglycosides and fluoroquinolones susceptibility