118 research outputs found

    Bar-induced central star formation as revealed by integral field spectroscopy from CALIFA

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    We investigate the recent star formation history (SFH) in the inner region of 57 nearly face-on spiral galaxies selected from the Calar Alto Legacy Integral Field Area (CALIFA) survey. For each galaxy we use the integral field spectroscopy from CALIFA to obtain two-dimensional maps and radial profiles of three parameters that are sensitive indicators of the recent SFH: the 4000\AA\ break (Dn_n(4000)), and the equivalent width of Hδ\delta absorption (EW(HδA\delta_A)) and Hα\alpha emission (EW(Hα\alpha)). We have also performed photometric decomposition of bulge/bar/disk components based on SDSS optical image. We identify a class of 17 "turnover" galaxies whose central region present significant drop in Dn_n(4000), and most of them correspondingly show a central upturn in EW(HδA\delta_A) and EW(Hα\alpha). This indicates that the central region of the turnover galaxies has experienced star formation in the past 1-2 Gyr, which makes the bulge younger and more star-forming than surrounding regions. We find almost all (15/17) the turnover galaxies are barred, while only half of the barred galaxies in our sample (15/32) are classified as a turnover galaxy. This finding provides strong evidence in support of the theoretical expectation that the bar may drive gas from the disc inward to trigger star formation in galaxy center, an important channel for the growth/rejuvenation of pseudobulges in disc galaxies.Comment: 19 pages, 10 figures, ApJ accepte

    Study on Soybean Resistance to Aphids

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    Soybean is the principal oil-producing crop in Liaoning Province and northeast of China. Soybean aphid (Aphis Glycines Matsmura) is a common insect pest and occurs almost every year. Aphid damage causes shrinking of young leaves, hampering of roots, dwarfing of stems and leaves, and reduction of pod and kernel numbers in the soybean plant. More than half of yield is lost in a severely damaged field. It is becoming one of the most important constraints to stable and high soybean yield. At present, spraying chemical insecticide is the major method for aphid control. Although it has taken effect, it requires numerous manpower, material and financial resources every year. Furthermore, it causes environmental pollution, is poisonous to people and animals, and injurious to natural enemies of soybean aphid. Pest resistance to constantly used chemical pesticides will reduce control efficiency and will cause an outbreak of pests again. In 1951, Painter, an American scientist, suggested the theory of plant resistance to insect pests after analyzing a large amount of research data, and he aroused the interest of scientists in different countries. Selection and breeding for plant resistance to insects have become basic modes of integrated pest control presently and for the future. From 1979 to 1985, Guo et al. successfully identified the resistance of soybeans to aphids and obtained a quantity of source material. On the basis of that work, this study on plant resistance to aphids was developed.Originating text in Chinese.Citation: He, Fugang, Liu, Xiaodong, Yan, Fanyue, Wang, Yanqin. (1995). Study on Soybean Resistance to Aphids. Liaoning Agricultural Science, 4, 30-34

    Optimum Spraying Time and Management Guidelines for Soybean Aphid Control

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    In Liaoning Province, the population of soybean aphid, Aphis glycines Matsumura, increases the most rapidly in late June, which is the critical period for aphid control. The current guideline for spraying is 10,000 aphids per100 plants. This guideline may be relaxed to 23,800 - 40,700 for cultivar Tiefeng #18 and to 26,500 – 33,000 for cultivar Liaodou #3 in the plains region found in the middle and lower reaches of Liaohe River. It is difficult to use aphid numbers as a management guideline in agricultural practice. According to our studies, the ratio of infested plants with rolled leaves is closely correlated to the aphid number per 100 plants. The linear regression equation is ? = 4.283 + 1.8419x (r = 0.90), where ? is the rolled leaf ratio and x is the aphid numbers per 100 plants. Therefore, instead of aphid numbers per 100 plants, we propose to use the ratio of plants with rolled leaves as the management guideline for large-scale field control of soybean aphids, which is 10% for Tiefeng #18 and 8% for Liaodou #3.Originating text in Chinese.Citation: He, Fugang, Yan, Fanyyue, Xin, Wanmin, Lii, Xiaoping, Wang, Yanqin, Zhang, Guangxue. (1991). Optimum Spraying Time and Management Guidelines for Soybean Aphid Control. Acta Phytophylacica Sinica, 18(2), 155-159

    Dark against luminous matter around isolated central galaxies: a comparative study between modern surveys and Illustris-TNG

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    Based on independent shear measurements using the DECaLS/DR8 imaging data, we measure the weak lensing signals around isolated central galaxies (ICGs) from SDSS/DR7 at z0.1z\sim0.1. The projected stellar mass density profiles of surrounding satellite galaxies are further deduced, using photometric sources from the Hyper Suprime-Cam (HSC) survey (pDR3). The signals of ICGs ++ their extended stellar halos are taken from Wang et al.(2021). All measurements are compared with predictions by the Illustris-TNG300-1 simulation. We find, overall, a good agreement between observation and TNG300. In particular, a correction to the stellar mass of massive observed ICGs is applied based on the calibration of He et al.(2013), which brings a much better agreement with TNG300 predicted lensing signals at log10M/M>11.1\log_{10}M_\ast/M_\odot>11.1. In real observation, red ICGs are hosted by more massive dark matter halos, have more satellites and more extended stellar halos than blue ICGs at fixed stellar mass. However, in TNG300 there are more satellites around blue ICGs at fixed stellar mass, and the outer stellar halos of red and blue ICGs are similar. The stellar halos of TNG galaxies are more extended compared with real observed galaxies, especially for blue ICGs with log10M/M>10.8\log_{10}M_\ast/M_\odot>10.8. We find the same trend for TNG100 galaxies and for true halo central galaxies. The tensions between TNG and real galaxies might indicate that satellite disruptions are stronger in TNG. In both TNG300 and observation, satellites approximately trace the underlying dark matter distribution beyond 0.1R2000.1R_{200}, but the fraction of total stellar mass in TNG300 does not show the same radial distribution as real galaxies.Comment: 28 pages, 12 figure

    The taxonomic relevance of flower colour for Epimedium (Berberidaceae), with morphological and nomenclatural notes for five species from China

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    Morphological variations, particularly flower colour, could be considered as an evolutionarily and ornamentally significant taxonomic criterion for Epimedium. Our extensive field investigation based on population studies revealed abundant intraspecific variations in flower colour. Five species, (i.e., E. acuminatum Franch., E. leptorrhizum Stearn, E. pauciflorum K.C.Yen, E. mikinorii Stearn, and E. glandulosopilosum H.R.Liang) were found to possess polymorphic flower colour, which is first described and illustrated here. Moreover, all these species were found to be polymorphic in other diagnostic characters, such as the type of rhizome, the number and arrangement of stem-leaves, and/or their indumentum, which have not been adequately described in previous studies. Therefore, their morphological descriptions have been complemented and/or revised. We also provide notes on the morphology and nomenclature for each species. Additionally, a key to the species in China has been provided. The present study could serve as a basis for understanding their taxonomy and helping their utilisation as an ornamental plant

    A sacrificial coating strategy toward enhancement of metal-support interaction for ultrastable Au nanocatalysts

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    Supported gold (Au) nanocatalysts hold great promise for heterogeneous catalysis; however, their practical application is greatly hampered by poor thermodynamic stability. Herein, a general synthetic strategy is reported where discrete metal nanoparticles are made resistant to sintering, preserving their catalytic activities in high-temperature oxidation processes. Taking advantage of the unique coating chemistry of dopamine, sacrificial carbon layers are constructed on the material surface, stabilizing the supported catalyst. Upon annealing at high temperature under an inert atmosphere, the interactions between support and metal nanoparticle are dramatically enhanced, while the sacrificial carbon layers can be subsequently removed through oxidative calcination in air. Owing to the improved metal–support contact and strengthened electronic interactions, the resulting Au nanocatalysts are resistant to sintering and exhibit excellent durability for catalytic combustion of propylene at elevated temperatures. Moreover, the facile synthetic strategy can be extended to the stabilization of other supported catalysts on a broad range of supports, providing a general approach to enhancing the thermal stability and sintering resistance of supported nanocatalysts

    Microbiome-derived bile acids contribute to elevated antigenic response and bone erosion in rheumatoid arthritis

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    Rheumatoid arthritis (RA) is a chronic, disabling and incurable autoimmune disease. It has been widely recognized that gut microbial dysbiosis is an important contributor to the pathogenesis of RA, although distinct alterations in microbiota have been associated with this disease. Yet, the metabolites that mediate the impacts of the gut microbiome on RA are less well understood. Here, with microbial profiling and non-targeted metabolomics, we revealed profound yet diverse perturbation of the gut microbiome and metabolome in RA patients in a discovery set. In the Bacteroides-dominated RA patients, differentiation of gut microbiome resulted in distinct bile acid profiles compared to healthy subjects. Predominated Bacteroides species expressing BSH and 7a-HSDH increased, leading to elevated secondary bile acid production in this subgroup of RA patients. Reduced serum fibroblast growth factor-19 and dysregulated bile acids were evidence of impaired farnesoid X receptor-mediated signaling in the patients. This gut microbiota-bile acid axis was correlated to ACPA. The patients from the validation sets demonstrated that ACPA-positive patients have more abundant bacteria expressing BSH and 7a-HSDH but less Clostridium scindens expressing 7a-dehydroxylation enzymes, together with dysregulated microbial bile acid metabolism and more severe bone erosion than ACPA-negative ones. Mediation analyses revealed putative causal relationships between the gut microbiome, bile acids, and ACPA-positive RA, supporting a potential causal effect of Bacteroides species in increasing levels of ACPA and bone erosion mediated via disturbing bile acid metabolism. These results provide insights into the role of gut dysbiosis in RA in a manifestation-specific manner, as well as the functions of bile acids in this gut-joint axis, which may be a potential intervention target for precisely controlling RA conditions.Comment: 38 pages, 6 figure

    Circulating methylation level of HTR2A is associated with inflammation and disease activity in rheumatoid arthritis

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    ObjectivesHTR2A is previously identified as a susceptibility gene for rheumatoid arthritis (RA). In this study, we performed the association analysis between DNA methylation of HTR2A with RA within peripheral blood samples.MethodsWe enrolled peripheral blood samples from 235 patients with RA, 30 osteoarthritis (OA) patients, and 30 healthy controls. The DNA methylation levels of about 218 bp from chr13: 46898190 to chr13: 46897973 (GRCh38/hg38) around HTR2A cg15692052 from patients were analyzed by targeted methylation sequencing.ResultsWe measured methylation status for 7 CpGs in the promoter region of HTR2A and obseved overall methylation status are signficantly increased in RA compared with normal inviduals (FDR= 9.05 x 10-5). The average cg15692052 methylation levels (methylation score) showed a positive correlation with CRP (r=0.15, P=0.023). Compared with the OA group or HC group, the proportion of haplotypes CCCCCCC (FDR=0.02 and 2.81 x 10-6) is signficantly increased while TTTTTCC (FDR =0.01) and TTTTTTT(FDR =6.92 x 10-3) are significantly decreased in RA. We find methylation haplotypes combining with RF and CCP could signficantly enhance the performance of the diagnosing RA and its comorbidities (hypertension, interstitial lung disease, and osteoporosis), especially in interstitial lung disease.ConclusionsIn our study, we found signficant hypermethylation of promoter region of HTR2A which indicates the potential clinical diagnostic role in rheumatoid arthritis

    A comprehensive review of Tripterygium wilfordii hook. f. in the treatment of rheumatic and autoimmune diseases: Bioactive compounds, mechanisms of action, and future directions

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    Rheumatic and autoimmune diseases are a group of immune system-related disorders wherein the immune system mistakenly attacks and damages the body’s tissues and organs. This excessive immune response leads to inflammation, tissue damage, and functional impairment. Therapeutic approaches typically involve medications that regulate immune responses, reduce inflammation, alleviate symptoms, and target specific damaged organs. Tripterygium wilfordii Hook. f., a traditional Chinese medicinal plant, has been widely studied in recent years for its application in the treatment of autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, and multiple sclerosis. Numerous studies have shown that preparations of Tripterygium wilfordii have anti-inflammatory, immunomodulatory, and immunosuppressive effects, which effectively improve the symptoms and quality of life of patients with autoimmune diseases, whereas the active metabolites of T. wilfordii have been demonstrated to inhibit immune cell activation, regulate the production of inflammatory factors, and modulate the immune system. However, although these effects contribute to reductions in inflammatory responses and the suppression of autoimmune reactions, as well as minimize tissue and organ damage, the underlying mechanisms of action require further investigation. Moreover, despite the efficacy of T. wilfordii in the treatment of autoimmune diseases, its toxicity and side effects, including its potential hepatotoxicity and nephrotoxicity, warrant a thorough assessment. Furthermore, to maximize the therapeutic benefits of this plant in the treatment of autoimmune diseases and enable more patients to utilize these benefits, efforts should be made to strengthen the regulation and standardized use of T. wilfordii

    Persistent sulfate formation from London Fog to Chinese haze

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    Sulfate aerosols exert profound impacts on human and ecosystem health, weather, and climate, but their formation mechanism remains uncertain. Atmospheric models consistently underpredict sulfate levels under diverse environmental conditions. From atmospheric measurements in two Chinese megacities and complementary laboratory experiments, we show that the aqueous oxidation of SO2 by NO2 is key to efficient sulfate formation but is only feasible under two atmospheric conditions: on fine aerosols with high relative humidity and NH3 neutralization or under cloud conditions. Under polluted environments, this SO2 oxidation process leads to large sulfate production rates and promotes formation of nitrate and organic matter on aqueous particles, exacerbating severe haze development. Effective haze mitigation is achievable by intervening in the sulfate formation process with enforced NH3 and NO2 control measures. In addition to explaining the polluted episodes currently occurring in China and during the 1952 London Fog, this sulfate production mechanism is widespread, and our results suggest a way to tackle this growing problem in China and much of the developing world
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