High reward enhances perceptual learning.

Studies of perceptual learning have revealed a great deal of plasticity in adult humans. In this study, we systematically investigated the effects and mechanisms of several forms (trial-by-trial, block, and session rewards) and levels (no, low, high, subliminal) of monetary reward on the rate, magnitude, and generalizability of perceptual learning. We found that high monetary reward can greatly promote the rate and boost the magnitude of learning and enhance performance in untrained spatial frequencies and eye without changing interocular, interlocation, and interdirection transfer indices. High reward per se made unique contributions to the enhanced learning through improved internal noise reduction. Furthermore, the effects of high reward on perceptual learning occurred in a range of perceptual tasks. The results may have major implications for the understanding of the nature of the learning rule in perceptual learning and for the use of reward to enhance perceptual learning in practical applications

Genetic variants in ELOVL2 and HSD17B12 predict melanoma‐specific survival

Fatty acids play a key role in cellular bioenergetics, membrane biosynthesis and intracellular signaling processes and thus may be involved in cancer development and progression. In the present study, we comprehensively assessed associations of 14,522 common single‐nucleotide polymorphisms (SNPs) in 149 genes of the fatty‐acid synthesis pathway with cutaneous melanoma disease‐specific survival (CMSS). The dataset of 858 cutaneous melanoma (CM) patients from a published genome‐wide association study (GWAS) by The University of Texas M.D. Anderson Cancer Center was used as the discovery dataset, and the identified significant SNPs were validated by a dataset of 409 CM patients from another GWAS from the Nurses’ Health and Health Professionals Follow‐up Studies. We found 40 noteworthy SNPs to be associated with CMSS in both discovery and validation datasets after multiple comparison correction by the false positive report probability method, because more than 85% of the SNPs were imputed. By performing functional prediction, linkage disequilibrium analysis, and stepwise Cox regression selection, we identified two independent SNPs of ELOVL2 rs3734398 T>C and HSD17B12 rs11037684 A>G that predicted CMSS, with an allelic hazards ratio of 0.66 (95% confidence interval = 0.51–0.84 and p = 8.34 × 10−4) and 2.29 (1.55–3.39 and p = 3.61 × 10−5), respectively. Finally, the ELOVL2 rs3734398 variant CC genotype was found to be associated with a significantly increased mRNA expression level. These SNPs may be potential markers for CM prognosis, if validated by additional larger and mechanistic studies

Learning the Relation between Similarity Loss and Clustering Loss in Self-Supervised Learning

Self-supervised learning enables networks to learn discriminative features from massive data itself. Most state-of-the-art methods maximize the similarity between two augmentations of one image based on contrastive learning. By utilizing the consistency of two augmentations, the burden of manual annotations can be freed. Contrastive learning exploits instance-level information to learn robust features. However, the learned information is probably confined to different views of the same instance. In this paper, we attempt to leverage the similarity between two distinct images to boost representation in self-supervised learning. In contrast to instance-level information, the similarity between two distinct images may provide more useful information. Besides, we analyze the relation between similarity loss and feature-level cross-entropy loss. These two losses are essential for most deep learning methods. However, the relation between these two losses is not clear. Similarity loss helps obtain instance-level representation, while feature-level cross-entropy loss helps mine the similarity between two distinct images. We provide theoretical analyses and experiments to show that a suitable combination of these two losses can get state-of-the-art results. Code is available at https://github.com/guijiejie/ICCL.Comment: This paper is accepted by IEEE Transactions on Image Processin

Influence of suspended sediment front on nutrients and phytoplankton dynamics off the Changjiang Estuary: A FVCOM-ERSEM coupled model experiment

Under embargo until: 2021-12-27High-turbidity water is a common feature in the estuary and inner shelf. Sediment suspension functions as a modulator that directly influences the interactions among nutrients, phytoplankton and other related ecosystem variables. A physical-biological coupling model system was applied to examine the impact of sediment front on interactions among on suspended sediment, vertical mixing, nutrients and phytoplankton over the inner shelf off the high-turbidity, phosphate-limited Changjiang Estuary. The physical model was the Finite-Volume Community Ocean Model (FVCOM) and the biological model was the European Regional Seas Ecosystem Model (ERSEM). Results revealed that in the nearshore region the growth of phytoplankton over the spring-summer seasons was limited by suspended sediments and intensified vertical mixing during the autumn-winter seasons extended the sediment-induced suppression extended offshore to restrict the phytoplankton growth over the shelf. Nutrients were diluted by spreading of freshwater discharge and significantly decreased off the suspended sediment front due to the depletion by the offshore phytoplankton growth. The simulation results showed that although the diatom phytoplankton dominated the Chlorophyll a (Chl-a) concentration, the non-diatom group had a more contribution to the biomass. The relatively high phytoplankton biomass was found over the offshore deep underwater valley area as results of remote advection by the Taiwan Warm Current and weak turbulent mixing.acceptedVersio

Two-tiered mutualism improves survival and competitiveness of cross-feeding soil bacteria.

Metabolic cross-feeding is a pervasive microbial interaction type that affects community stability and functioning and directs carbon and energy flows. The mechanisms that underlie these interactions and their association with metal/metalloid biogeochemistry, however, remain poorly understood. Here, we identified two soil bacteria, Bacillus sp. BP-3 and Delftia sp. DT-2, that engage in a two-tiered mutualism. Strain BP-3 has low utilization ability of pyruvic acid while strain DT-2 lacks hexokinase, lacks a phosphotransferase system, and is defective in glucose utilization. When strain BP-3 is grown in isolation with glucose, it releases pyruvic acid to the environment resulting in acidification and eventual self-killing. However, when strain BP-3 is grown together with strain DT-2, strain DT-2 utilizes the released pyruvic acid to meet its energy requirements, consequently rescuing strain BP-3 from pyruvic acid-induced growth inhibition. The two bacteria further enhance their collective competitiveness against other microbes by using arsenic as a weapon. Strain DT-2 reduces relatively non-toxic methylarsenate [MAs(V)] to highly toxic methylarsenite [MAs(III)], which kills or suppresses competitors, while strain BP-3 detoxifies MAs(III) by methylation to non-toxic dimethylarsenate [DMAs(V)]. These two arsenic transformations are enhanced when strains DT-2 and BP-3 are grown together. The two strains, along with their close relatives, widely co-occur in soils and their abundances increase with the soil arsenic concentration. Our results reveal that these bacterial types employ a two-tiered mutualism to ensure their collective metabolic activity and maintain their ecological competitive against other soil microbes. These findings shed light on the intricateness of bacterial interactions and their roles in ecosystem functioning

Antioxidant and hypoglycemic activities of different graded fractions of polysaccharide from goldenmelon

Objective: The study aimed to research the physicochemical properties, structure, antioxidant activity and hypoglycemic activity of different fractions of polysaccharide of goldenmelon. Methods: Four kinds of goldenmelon polysaccharides (CP-40, CP-60, CP-70, CP-80) were obtained by graded purification of water extraction and alcoholic precipitation. Their molecular weight, monosaccharide composition, group composition, antioxidant and hypoglycemic activities were investigated by high performance liquid chromatography and fourier transform infrared spectroscopy. Results: With the increase of ethanol volume fraction, the total sugar content increased and the glucuronic acid content decreased. The molecular weights of these four polysaccharides were different, which indicated by the same composition of monosaccharides but different composition ratios, and they all had the characteristic absorption peaks of polysaccharides. The antioxidant capacity and hypoglycemic activity of the polysaccharides in vitro had obvious quantity-effect relationships, CP-70 had the strongest antioxidant effect on DPPH radicals, hydroxyl radicals and superoxide anions scavenging than other groups, while CP-80 had the best hypoglycemic activity since it had the strongest inhibitory effects on α-glucosidase and α-amylase. Conclusion: The polysaccharide of goldenmelon had good antioxidant properties and hypoglycemic activity

vWA proteins of Leptospira interrogans induce hemorrhage in leptospirosis by competitive inhibition of vWF/GPIb-mediated platelet aggregation.

BACKGROUD: Leptospira interrogans is the major causative agent of leptospirosis, a worldwide zoonotic disease. Hemorrhage is a typical pathological feature of leptospirosis. Binding of von Willebrand factor (vWF) to platelet glycoprotein-Ibα (GPIbα) is a crucial step in initiation of platelet aggregation. The products of L. interrogans vwa-I and vwa-II genes contain vWF-A domains, but their ability to induce hemorrhage has not been determined. METHODS: Human (Hu)-platelet- and Hu-GPIbα-binding abilities of the recombinant proteins expressed by L. interrogans strain Lai vwa-I and vwa-II genes (rLep-vWA-I and rLep-vWA-II) were detected by flowcytometry, surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC). Hu-platelet aggregation and its signaling kinases and active components were detected by lumiaggregometry, Western analysis, spectrophotometry and confocal microscopy. Hu-GPIbα-binding sites in rLep-vWA-I and rLep-vWA-II were identified by SPR/ITC measurements. FINDINGS: Both rLep-vWA-I and rLep-vWA-II were able to bind to Hu-platelets and inhibit rHu-vWF/ristocetin-induced Hu-platelet aggregation, but Hu-GPIbα-IgG, rLep-vWA-I-IgG and rLep-vWA-II-IgG blocked this binding or inhibition. SPR and ITC revealed a tight interaction between Hu-GPIbα and rLep-vWA-I/rLep-vWA-II with K INTERPRETATION: The products of L. interrogans vwa-I and vwa-II genes induce hemorrhage by competitive inhibition of vWF-mediated Hu-platelet aggregation