68 research outputs found

    Globally invariant metabolism but density-diversity mismatch in springtails.

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    Soil life supports the functioning and biodiversity of terrestrial ecosystems. Springtails (Collembola) are among the most abundant soil arthropods regulating soil fertility and flow of energy through above- and belowground food webs. However, the global distribution of springtail diversity and density, and how these relate to energy fluxes remains unknown. Here, using a global dataset representing 2470 sites, we estimate the total soil springtail biomass at 27.5 megatons carbon, which is threefold higher than wild terrestrial vertebrates, and record peak densities up to 2 million individuals per square meter in the tundra. Despite a 20-fold biomass difference between the tundra and the tropics, springtail energy use (community metabolism) remains similar across the latitudinal gradient, owing to the changes in temperature with latitude. Neither springtail density nor community metabolism is predicted by local species richness, which is high in the tropics, but comparably high in some temperate forests and even tundra. Changes in springtail activity may emerge from latitudinal gradients in temperature, predation and resource limitation in soil communities. Contrasting relationships of biomass, diversity and activity of springtail communities with temperature suggest that climate warming will alter fundamental soil biodiversity metrics in different directions, potentially restructuring terrestrial food webs and affecting soil functioning

    Global fine-resolution data on springtail abundance and community structure

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    Springtails (Collembola) inhabit soils from the Arctic to the Antarctic and comprise an estimated ~32% of all terrestrial arthropods on Earth. Here, we present a global, spatially-explicit database on springtail communities that includes 249,912 occurrences from 44,999 samples and 2,990 sites. These data are mainly raw sample-level records at the species level collected predominantly from private archives of the authors that were quality-controlled and taxonomically-standardised. Despite covering all continents, most of the sample-level data come from the European continent (82.5% of all samples) and represent four habitats: woodlands (57.4%), grasslands (14.0%), agrosystems (13.7%) and scrublands (9.0%). We included sampling by soil layers, and across seasons and years, representing temporal and spatial within-site variation in springtail communities. We also provided data use and sharing guidelines and R code to facilitate the use of the database by other researchers. This data paper describes a static version of the database at the publication date, but the database will be further expanded to include underrepresented regions and linked with trait data.</p

    Key Technologies in Massive MIMO

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    The explosive growth of wireless data traffic in the future fifth generation mobile communication system (5G) has led researchers to develop new disruptive technologies. As an extension of traditional MIMO technology, massive MIMO can greatly improve the throughput rate and energy efficiency, and can effectively improve the link reliability and data transmission rate, which is an important research direction of 5G wireless communication. Massive MIMO technology is nearly three years to get a new technology of rapid development and it through a lot of increasing the number of antenna communication, using very duplex communication mode, make the system spectrum efficiency to an unprecedented height

    Key Technologies in Massive MIMO

    No full text
    The explosive growth of wireless data traffic in the future fifth generation mobile communication system (5G) has led researchers to develop new disruptive technologies. As an extension of traditional MIMO technology, massive MIMO can greatly improve the throughput rate and energy efficiency, and can effectively improve the link reliability and data transmission rate, which is an important research direction of 5G wireless communication. Massive MIMO technology is nearly three years to get a new technology of rapid development and it through a lot of increasing the number of antenna communication, using very duplex communication mode, make the system spectrum efficiency to an unprecedented height

    Description of the octopunctata - group species of Protaphorura from China (Collembola: Onychiuridae)

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    Sun, Xin, Wu, Donghui, Gao, Meixiang (2013): Description of the octopunctata - group species of Protaphorura from China (Collembola: Onychiuridae). Zootaxa 3710 (4): 363-371, DOI: 10.11646/zootaxa.3710.4.

    The Use of linguistic cues in sentence comprehension by Mandarin-speaking children with high-functioning autism

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    Two studies were conducted to investigate how high-functioning children with autism use different linguistic cues in sentence comprehension. Two types of linguistic cues were investigated: word order and morphosyntactic cues. The results show that children with autism can use both types of cues in sentence comprehension. However, compared to age-matched typically developing peers, children with autism relied significantly more on word order cues and exhibited significantly more difficulties in interpreting sentences in which there was a conflict between the morphosyntactic cue and the word order cue. We attribute the difficulties exhibited by children with autism to their deficits in executive function. We then discuss the implications of the findings for understanding the nature of the sentence processing mechanism in autism.16 page(s

    Two new onychiurid species (Collembola, Onychiurinae) inhabiting morel fruit bodies in southwest China

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    Liu, Jie, Gao, Meixiang, Xie, Zhijing, Sun, Xin (2019): Two new onychiurid species (Collembola, Onychiurinae) inhabiting morel fruit bodies in southwest China. Zootaxa 4576 (2): 367-374, DOI: https://doi.org/10.11646/zootaxa.4576.2.1

    Transformation of Corn Stover into Furan Aldehydes by One-Pot Reaction with Acidic Lithium Bromide Solution

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    Currently, the production of furan aldehydes from raw biomass suffers from low furfural yield and high energy consumption. In this study, a recyclable and practical method was explored for the preparation of furfural from corn stover by the one-pot reaction by acidic lithium bromide solution (ALBS) without pretreatment and enzymolysis. In the ALBS reaction, the furan aldehydes were generated by the degradation of lignocellulose; however, the products were unstable and were further dehydrated to form humins. So, dehydration reaction was inhibited in this study, and the high yield of furan aldehydes was obtained, in which 2.94 g/L of furfural and 2.78 g/L of 5-hydroxymethyl furfural (5-HMF) were generated with high solid loading (10 wt%), the presence of commercial catalyst ZSM-5 and co-solvent tetrahydrofuran (THF) at 140 &deg;C for 200 min. Via this method, almost 100% of hemicellulose was transformed to furfural, and 40.71% of cellulose was transformed to 5-HMF, which was based on the theoretical yield of HMF (8.35 g) from glucose (29.30 g) produced from cellulose. After the reaction, the catalyst ZSM-5 was the main component in the solid residue and kept a suitable performance. THF azeotrope was easily separated from the slurry by evaporation. During the removal of THF, lignin was precipitated from the liquid phase and showed lower molecular weight and abundant active groups, which was a potential feedstock for producing valuable aromatics and polymers. Thus, in a one-pot reaction, the ideal yield of furan aldehydes from raw biomass was obtained on a lab scale, and the catalyst, THF, and LiBr were easily recycled, which provided an option to realize the economical production of sustainable furan aldehydes from raw biomass

    A rapid HPLC/ESI-MS/MS method for quantitative analysis of isovalerylshikonin in rat plasma

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    A new, fast and sensitive high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS) method was developed and validated for isovalerylshikonin in rat plasma using emodin as internal standard (15). The analyte was extracted from rat plasma with ethyl acetate, after 10% HCl treatment and protein precipitated by methanol. The compound was separated on an Ultimate (TM) XB-C-18 analytical column using a mobile phase of methanol-10 mm ammonium acetate in water-acetonitrile containing 0.05% formic acid (45:10:45, v/v/v) with isogradient elution. The analyte was detected in negative ion mode using multiple-reaction monitoring. The method was validated and the specificity, linearity, lower limit of quantitation (LLOQ), precision, accuracy, recoveries and stability were determined. LLOQ was 9 ng/mL for isovalerylshikonin. Correlation coefficient (r) value for the linear range of the analyte was greater than 0.99. The intra-day and inter-day precision and accuracy were better than 8.52%. The relative and absolute recovery was above 86% and no matrix effects were observed for isovalerylshikonin. This validated method provides a modern, rapid and robust procedure for the pharmacokinetic study of the two compounds in rats after intravenous administration to rats (n = 4). Copyright (C) 2009 John Wiley & Sons, Ltd.National Natural Science Foundation of China [20732004]; Ministry of Science and Technology of the People's Republic of China [2006DFA43030

    The Use of grammatical morphemes by Mandarin-speaking children with high functioning autism

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    The present study investigated the production of grammatical morphemes by Mandarin-speaking children with high functioning autism. Previous research found that a subgroup of English-speaking children with autism exhibit deficits in the use of grammatical morphemes that mark tense. In order to see whether this impairment in grammatical morphology can be generalised to children with autism from other languages, the present study examined whether or not high-functioning Mandarin-speaking children with autism also exhibit deficits in using grammatical morphemes that mark aspect. The results show that Mandarin-speaking children with autism produced grammatical morphemes significantly less often than age-matched and IQ-matched TD peers as well as MLU-matched TD peers. The implications of these findings for understanding the grammatical abilities of children with autism were discussed.9 page(s
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