CDLT: A Dataset with Concept Drift and Long-Tailed Distribution for Fine-Grained Visual Categorization

Data is the foundation for the development of computer vision, and the establishment of datasets plays an important role in advancing the techniques of fine-grained visual categorization~(FGVC). In the existing FGVC datasets used in computer vision, it is generally assumed that each collected instance has fixed characteristics and the distribution of different categories is relatively balanced. In contrast, the real world scenario reveals the fact that the characteristics of instances tend to vary with time and exhibit a long-tailed distribution. Hence, the collected datasets may mislead the optimization of the fine-grained classifiers, resulting in unpleasant performance in real applications. Starting from the real-world conditions and to promote the practical progress of fine-grained visual categorization, we present a Concept Drift and Long-Tailed Distribution dataset. Specifically, the dataset is collected by gathering 11195 images of 250 instances in different species for 47 consecutive months in their natural contexts. The collection process involves dozens of crowd workers for photographing and domain experts for labelling. Extensive baseline experiments using the state-of-the-art fine-grained classification models demonstrate the issues of concept drift and long-tailed distribution existed in the dataset, which require the attention of future researches

The Complete Genome Sequence of ‘Candidatus Liberibacter solanacearum’, the Bacterium Associated with Potato Zebra Chip Disease

Zebra Chip (ZC) is an emerging plant disease that causes aboveground decline of potato shoots and generally results in unusable tubers. This disease has led to multi-million dollar losses for growers in the central and western United States over the past decade and impacts the livelihood of potato farmers in Mexico and New Zealand. ZC is associated with ‘Candidatus Liberibacter solanacearum’, a fastidious alpha-proteobacterium that is transmitted by a phloem-feeding psyllid vector, Bactericera cockerelli Sulc. Research on this disease has been hampered by a lack of robust culture methods and paucity of genome sequence information for ‘Ca. L. solanacearum’. Here we present the sequence of the 1.26 Mbp metagenome of ‘Ca. L. solanacearum’, based on DNA isolated from potato psyllids. The coding inventory of the ‘Ca. L. solanacearum’ genome was analyzed and compared to related Rhizobiaceae to better understand ‘Ca. L. solanacearum’ physiology and identify potential targets to develop improved treatment strategies. This analysis revealed a number of unique transporters and pathways, all potentially contributing to ZC pathogenesis. Some of these factors may have been acquired through horizontal gene transfer. Taxonomically, ‘Ca. L. solanacearum’ is related to ‘Ca. L. asiaticus’, a suspected causative agent of citrus huanglongbing, yet many genome rearrangements and several gene gains/losses are evident when comparing these two Liberibacter. species. Relative to ‘Ca. L. asiaticus’, ‘Ca. L. solanacearum’ probably has reduced capacity for nucleic acid modification, increased amino acid and vitamin biosynthesis functionalities, and gained a high-affinity iron transport system characteristic of several pathogenic microbes

The influence of urban park characteristics on bird diversity in Nanjing, China

Abstract Background Habitat loss, fragmentation and decrease of habitat quality caused by urbanization have led to a dramatic decline in biodiversity worldwide. For highly urbanized areas, parks have become “islands” or habitat fragments for wildlife. As an important indicator group of urban ecosystem health, the response of birds to urbanization has attracted the global attention of ecologists. Understanding the key factors affecting bird diversity in urbanized environment is crucial to the protection of biodiversity in urban ecosystems. Methods We used the line-transect method to survey birds in 37 urban parks in Nanjing, China. We also measured a number of park characteristics (area, isolation, shape index, environmental noise, distance to city center, and habitat diversity) that are commonly assumed to influence bird diversity. We then used the information-theoretic multi-model inference approach to determine which park characteristics had significant impacts on bird species richness. Results We found that park area, habitat diversity and the distance to city center were the best positive predictors of bird species richness in Nanjing urban parks. By contrast, park isolation, park shape and environmental noise had little or no influence on bird diversity. Conclusions Our study highlights the importance of park area, habitat diversity and the distance to city center in determining bird diversity in Nanjing city parks. Therefore, from a conservation viewpoint, we recommend that large parks with complex and diverse habitats far away from the city center should be retained or constructed to increase bird diversity in urban design and planning

A Novel Optical Path for Enhancing the Performance of High-Power Semiconductor Laser in Packaging

High-power semiconductor laser has more significant applications in long distance and high-reliability optical communication systems. It is noticed that the packaging plays an important role in the performance of high-power semiconductor laser, including high output power, high coupling efficiency, low relative intensity noise (RIN), and so on. Usually, in a symmetrical optical path, the light, which incident directly parallel to the optical axis of the lens, will be partially reflected back to the laser and cause noise. To solve this problem, a novel asymmetric optical path is designed and implemented to meet the requirement of using a high-power laser with low RIN in this work. By employing an isolator between the first and second lens, the laser with high beam quality and low reflection of the signal was achieved. Moreover, the optical focal length of the collimating lens and the angle of the inclined lens were optimized by simulation. The proposed laser exhibited high coupling efficiency with a RIN of −168.89 dB/Hz. According to theoretical and experimental analysis, the performance of the laser will be helpful in fabricating a high-power laser with low RIN for next-generation optical communication

Gradient Learning under Tilted Empirical Risk Minimization

Gradient Learning (GL), aiming to estimate the gradient of target function, has attracted much attention in variable selection problems due to its mild structure requirements and wide applicability. Despite rapid progress, the majority of the existing GL works are based on the empirical risk minimization (ERM) principle, which may face the degraded performance under complex data environment, e.g., non-Gaussian noise. To alleviate this sensitiveness, we propose a new GL model with the help of the tilted ERM criterion, and establish its theoretical support from the function approximation viewpoint. Specifically, the operator approximation technique plays the crucial role in our analysis. To solve the proposed learning objective, a gradient descent method is proposed, and the convergence analysis is provided. Finally, simulated experimental results validate the effectiveness of our approach when the input variables are correlated

The Functional <i>TP53</i> rs1042522 and <i>MDM4</i> rs4245739 Genetic Variants Contribute to Non-Hodgkin Lymphoma Risk

<div><p>As a heterogeneous kind of malignances, Non-Hodgkin lymphoma (NHL) is the most common hematologic cancer worldwide with the significantly increased morbidity in China. Accumulated evidences demonstrated that oncoprotein MDM4 plays a crucial role in the TP53 tumor suppressor signaling pathway. An rs4245739 A>C polymorphism locating in the <i>MDM4</i> 3′-untranslated region creates a miR-191 target site and results in allele-specific MDM4 expression. In this study, we examined the association between this polymorphism as well as the <i>TP53</i> Arg72Pro (rs1042522 G>C) genetic variant and Non-Hodgkin Lymphoma (NHL) risk in a Chinese Han population. Genotypes were determined in 200 NHL cases and 400 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by logistic regression. We found significantly increased NHL risk among carriers of the <i>TP53</i> 72Pro allele compared with those with the 72Arg allele (<i>P</i> = 0.002 for the Pro/Pro genotype). We also observed a significantly decreased NHL risks among carriers of the <i>MDM4</i> rs4245739 C allele compared with those with the A allele in Chinese (<i>P</i> = 0.014 for the AC genotype). Stratified analyses revealed the associations between these SNPs and NHL risk are especially noteworthy in young or male individuals. Additionally, the associations are much pronounced in NHL patients with B-cell lymphomas or grade 3 or 4 disease. Our results indicate that the <i>TP53</i> Arg72Pro and the <i>MDM4</i> rs4245739 polymorphisms contribute to NHL susceptibility and support the hypothesis that genetic variants in the <i>TP53</i> pathway genes can act as important modifiers of NHL risk.</p></div

Associations between the <i>TP53</i> rs1042522 Arg72Pro and <i>MDM4</i> rs4245739 A>C genetic polymorphisms and Non-Hodgkin Lymphoma risk.

<p>Note: NHL: Non-Hodgkin Lymphoma, OR: odds ratio, 95%CI: 95% confidence interval, NC: not calculated.</p>a<p>Data were calculated by logistic regression, adjusted for sex and age.</p><p>Associations between the <i>TP53</i> rs1042522 Arg72Pro and <i>MDM4</i> rs4245739 A>C genetic polymorphisms and Non-Hodgkin Lymphoma risk.</p