•Visual scene stimuli share a common vertical luminance gradient (VLG).•VLG is correlated with cortical scene selectivity in complex, naturalistic stimuli.•Tightly controlled stimuli of VLG drive ...cortical scene selectivity.•Humans behaviorally categorize tightly controlled stimuli of VLG as a “place”.•Visual scenes may be characterized by a set of common and unique features.
Human neuroimaging studies have revealed a dedicated cortical system for visual scene processing. But what is a “scene”? Here, we use a stimulus-driven approach to identify a stimulus feature that selectively drives cortical scene processing. Specifically, using fMRI data from BOLD5000, we examined the images that elicited the greatest response in the cortical scene processing system, and found that there is a common “vertical luminance gradient” (VLG), with the top half of a scene image brighter than the bottom half; moreover, across the entire set of images, VLG systematically increases with the neural response in the scene-selective regions (Study 1). Thus, we hypothesized that VLG is a stimulus feature that selectively engages cortical scene processing, and directly tested the role of VLG in driving cortical scene selectivity using tightly controlled VLG stimuli (Study 2). Consistent with our hypothesis, we found that the scene-selective cortical regions—but not an object-selective region or early visual cortex—responded significantly more to images of VLG over control stimuli with minimal VLG. Interestingly, such selectivity was also found for images with an “inverted” VLG, resembling the luminance gradient in night scenes. Finally, we also tested the behavioral relevance of VLG for visual scene recognition (Study 3); we found that participants even categorized tightly controlled stimuli of both upright and inverted VLG to be a place more than an object, indicating that VLG is also used for behavioral scene recognition. Taken together, these results reveal that VLG is a stimulus feature that selectively engages cortical scene processing, and provide evidence for a recent proposal that visual scenes can be characterized by a set of common and unique visual features.
Abstract
Turbulent radiative mixing layers (TRMLs) form at the interface of cold, dense gas and hot, diffuse gas in motion with each other. TRMLs are ubiquitous in and around galaxies on a variety of ...scales, including galactic winds and the circumgalactic medium. They host the intermediate-temperature gases that are efficient in radiative cooling, thus playing a crucial role in controlling the cold gas supply, phase structure, and spectral features of galaxies. In this work, we develop an intuitive analytic 1.5-dimensional model for TRMLs that includes a simple parameterization of the effective turbulent conductivity and viscosity and a piecewise power-law cooling curve. Our analytic model reproduces the mass flux, total cooling, and phase structure of 3D simulations of TRMLs at a fraction of the computational cost. It also reveals essential insights into the physics of TRMLs, particularly the importance of the viscous dissipation of relative kinetic energy in balancing radiative cooling as the shear Mach number approaches unity. This dissipation takes place both in the intermediate-temperature phase, which reduces the enthalpy flux from the hot phase, and in the cold phase, which enhances radiative cooling. Additionally, our model provides a fast and easy way of computing the column density and surface brightness of TRMLs, which can be directly linked to observations.
Abstract
As the prevailing non-volatile memory (NVM), flash memory offers mass data storage at high integration density and low cost. However, due to the ‘speed-retention-endurance’ dilemma, their ...typical speed is limited to ~microseconds to milliseconds for program and erase operations, restricting their application in scenarios with high-speed data throughput. Here, by adopting metallic 1T-Li
x
MoS
2
as edge contact, we show that ultrafast (10–100 ns) and robust (endurance>10
6
cycles, retention>10 years) memory operation can be simultaneously achieved in a two-dimensional van der Waals heterostructure flash memory with 2H-MoS
2
as semiconductor channel. We attribute the superior performance to the gate tunable Schottky barrier at the edge contact, which can facilitate hot carrier injection to the semiconductor channel and subsequent tunneling when compared to a conventional top contact with high density of defects at the metal interface. Our results suggest that contact engineering can become a strategy to further improve the performance of 2D flash memory devices and meet the increasing demands of high speed and reliable data storage.
Infective endocarditis (IE) presents with increasing incidence and mortality in some regions and countries, as well as serious socioeconomic burden. The current study aims to compare and interpret ...the IE burden and temporal trends globally and in different regions from 1990 to 2019.
Data on the incidence, deaths and disability-adjusted life years (DALYs) caused by IE were extracted and analyzed from the Global Burden of Disease Study 2019. Estimated annual percentage changes (EAPC) were adopted to quantify the change trends of age-standardized rates (ASRs). Besides, potential contributors of serious IE burden were also evaluated including age, gender, social-demographic index (SDI), and age-standardized incident rate (ASIR) in 1990.
Globally, the number of IE cases and deaths has increased sharply during the past 30 years from 478,000 in 1990 to 1,090,530 in 2019 and from 28,750 in 1990 to 66,320 in 2019, and both presented an upward temporal trend annually (EAPC:1.2 for incidence and 0.71 for death). However, the EAPC of age-standardized DALYs demonstrated a negative temporal trend despite increasing DALYs from 1,118,120 in 1990 to 1,723,590 in 2019. Moreover, older patients and men were more severely affected. Meanwhile, different SDI regions had different disease burdens, and correlation analyses indicated that SDI presented a positive association with ASIR (R = 0.58,
< 0.0001), no association with age-standardized death rate (R = -0.06,
= 0.10), and a negative association with age-standardized DALYs (R = -0.40,
< 0.0001). In addition, the incidence of IE increased in most countries during the past 30 years (190 out of 204 countries). However, the change trends of deaths and DALYs were heterogeneous across regions and countries. Finally, we discovered positive associations of the EAPC of ASRs with the SDI in 2019 among 204 countries and territories but few associations with the ASIR in 1990.
Generally, the global burden of IE is increasing, and there is substantial heterogeneity in different genders, ages and regions, which may help policy-makers and medical staff respond to IE and formulate cost-effective interventional measures.
The NAC TF family is widely involved in plant responses to various types of stress. Red clover (Trifolium pratense) is a high-quality legume, and the study of NAC genes in red clover has not been ...comprehensive. The aim of this study was to analyze the NAC gene family of red clover at the whole-genome level and explore its potential role in the Pb stress response.
In this study, 72 TpNAC genes were identified from red clover; collinearity analysis showed that there were 5 pairs of large fragment replicators of TpNAC genes, and red clover was found to be closely related to Medicago truncatula. Interestingly, the TpNAC genes have more homologs in Arabidopsis thaliana than in soybean (Glycine max). There are many elements in the TpNAC genes promoters that respond to stress. Gene expression analysis showed that all the TpNAC genes responded to Pb stress. qRT-PCR showed that the expression levels of TpNAC29 and TpNAC42 were significantly decreased after Pb stress. Protein interaction network analysis showed that 21 TpNACs and 23 other genes participated in the interaction. In addition, the TpNAC proteins had three possible 3D structures, and the secondary structure of these proteins were mainly of other types. These results indicated that most TpNAC members were involved in the regulation of Pb stress in red clover.
These results suggest that most TpNAC members are involved in the regulation of Pb stress in red clover. TpNAC members play an important role in the response of red clover to Pb stress.
In pressurized water reactors, LiOH may be concentrated in some areas, leading to the accelerated corrosion of fuel claddings. Injecting boric acid into primary coolants can mitigate the accelerated ...corrosion effect of LiOH on Zircaloys, but the effects of boron content on the corrosion behavior of the Zr-Sn-Nb alloy are still unknown. This work focused on the corrosion and hydrogen absorption behavior at 360 °C/18.6 MPa in 100 mg/kg LiOH solutions with 0 mg/kg, 50 mg/kg, and 200 mg/kg boron contents for up to 510 days, aiming to study the effect of boron content on corrosion resistance in LiOH solutions. Corrosion kinetics, microstructures of oxide films, hydrogen absorption concentrations and hydride morphology were obtained after the test. The results show that injecting boron in LiOH solutions can significantly reduce the corrosion weight gain, hydrogen concentration, and hydrogen length of Zr-Sn-Nb alloys, that is, improving corrosion resistance effectively. During the oxidation of the Zr-Sn-Nb alloy, B
and Li
incorporate in oxide films. The incorporation of Li
may lead to the generation of oxygen vacancies, which can carry oxygen from the solutions to O/M interface, accelerating corrosion. The incorporation of B
in oxide films will slow down the oxidation of Zr-Sn-Nb alloys by reducing the oxygen vacancies caused by Li
aggregation.
Symbiotic nitrogen fixation is based on the symbiotic relationship between rhizobia and plants and a sustainable green way to maintain fertility in modern agriculture. However, the lack of a thorough ...understanding on the mechanisms seriously hinders the application of this biological way to enhance agricultural production. In the present study, we discovered an interesting mutation of NoiD in
Rhizobium leguminosarum
biovar
viciae
3841 (
R.l. viciae
3841). This DedA membrane protein, affected the phenotypic development on both rhizobia and host (
Pisum sativum
). Compared with
R.l. viciae
3841, the
noiD
mutant strain (△
noiD
) was present as independent small colonies, and the proportion of Rhizobium cells that were of shorter size increased. Inoculating △
noiD
to
Pisum sativum
resulted in premature senility and nodulation defects at 28 dpi with a 28.86% reduction of root nitrogen fixation efficiency compared to wild-type group. Furthermore, we showed that these are mainly attributed to an increase in temperature, pH, and ionic osmolarity sensitivity of the rhizobia with the
noiD
mutation. These results indicate that NoiD participates in the homeostasis mechanism of
R.l. viciae
3841, and can directly influence nodulation and nitrogen fixation efficiency in
Pisum sativum
.
Caucasian clover (Trifolium ambiguum M. Bieb.) is an excellent perennial plant in the legume family Fabaceae, with a well-developed rhizome and strong clonal growth. Auxin is one of the most ...important phytohormones in plants and plays an important role in plant growth and development. Auxin response factor (ARF) can regulate the expression of auxin-responsive genes, thus participating in multiple pathways of auxin transduction signaling in a synergistic manner. No genomic database has been established for Caucasian clover. In this study, 71 TaARF genes were identified through a transcriptomic database of Caucasian clover rhizome development. Phylogenetic analysis grouped the TaARFs into six (1–6) clades. Thirty TaARFs contained a complete ARF structure, including three relatively conserved regions. Physical and chemical property analysis revealed that TaARFs are unstable and hydrophilic proteins. We also analyzed the expression pattern of TaARFs in different tissues (taproot, horizontal rhizome, swelling of taproot, rhizome bud and rhizome bud tip). Quantitative real–time RT–PCR revealed that all TaARFs were responsive to phytohormones (indole-3-acetic acid, gibberellic acid, abscisic acid and methyl jasmonate) in roots, stems and leaves. These results helped elucidate the role of ARFs in responses to different hormone treatments in Caucasian clover.
Multivariate regression is a fundamental supervised chemometric method for developing the relationship between the independent variables and quantitative response, and it has been widely applied for ...data analysis in many research fields. In this study, we propose an effective method for the quantitative determination of target compounds in traditional Chinese medicine, specifically Mongolia, using excitation-emission matrix (EEM) spectra with partial overlap. The accuracy and reliability of the established model have been validated, demonstrating that the proposed method can realize the accurate quantitative analysis purpose. In order to facilitate the calculation easier, the authors have developed a friendly graphical user interface (GUI). The GUI offers the procedures for data imputation, model establishment, model optimization and results presentation.
