177 research outputs found

    The impacts of precipitation increase and nitrogen addition on soil respiration in a semiarid temperate steppe

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    Soil respiration, Rs, is strongly controlled by water availability in semiarid grasslands. However, how Rs is affected by precipitation change (either as rainfall or as snowfall) especially under increasing nitrogen (N) deposition has been uncertain. A manipulative experiment to investigate the responses of growing season Rs to changes in spring snowfall or summer rainfall with or without N addition was conducted in the semiarid temperate steppe of China during three hydrologically contrasting years. Our results showed that both spring snow addition and summer water addition significantly increased Rs by increasing soil moisture. The effect of spring snow addition only occurred in years with both relatively lower natural snowfall and later snowmelt time. Summer water addition showed a much stronger effect on Rs by increasing plant root growth and microbial activities, but the magnitude also largely depended on the possible legacy effect of previous year precipitation. Our results indicated that precipitation increase in the form of snowfall had weaker effects than that in the form of rainfall as the former only accounted for less than 30% of total precipitation. Compared with other ecosystem processes, Rs was less responsible for increase in N deposition as it did not increase root productivity and microbial activities in the soils. Our results provided field data constraints for modeling the ecosystem carbon balance under the future global change scenarios in semiarid grasslands

    PAR-1 Kinase Phosphorylates Dlg and Regulates Its Postsynaptic Targeting at the Drosophila Neuromuscular Junction

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    SummaryTargeting of synaptic molecules to their proper location is essential for synaptic differentiation and plasticity. PSD-95/Dlg proteins have been established as key components of the postsynapse. However, the molecular mechanisms regulating the synaptic targeting, assembly, and disassembly of PSD-95/Dlg are not well understood. Here we show that PAR-1 kinase, a conserved cell polarity regulator, is critically involved in controlling the postsynaptic localization of Dlg. PAR-1 is prominently localized at the Drosophila neuromuscular junction (NMJ). Loss of PAR-1 function leads to increased synapse formation and synaptic transmission, whereas overexpression of PAR-1 has the opposite effects. PAR-1 directly phosphorylates Dlg at a conserved site and negatively regulates its mobility and targeting to the postsynapse. The ability of a nonphosphorylatable Dlg to largely rescue PAR-1-induced synaptic defects supports the idea that Dlg is a major synaptic substrate of PAR-1. Control of Dlg synaptic targeting by PAR-1-mediated phosphorylation thus constitutes a critical event in synaptogenesis

    Development of a blocking logic checking apparatus for substation measurement and control devices

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    After transforming substation measurement and control devices, the traditional method of blocking logic check needs to go back and forth among the measurement and control devices, and repeatedly connect a large number of wires, which lead to tedious operation and low efficiency. This paper developed a logic verification device based on 4G wireless communication, which used the Modbus/TCP transport protocol to access Ethernet, to complete the real-time data communication with the mobile control terminal. And this paper made a request to the logic controller according to practicality and cost. And the terminal software interface was designed by the orthogonal experimental design idea. The development of this device provided a new and efficient method for logic verification

    An Improved Complexity Bound for Computing the Topology of a Real Algebraic Space Curve

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    We propose a new algorithm to compute the topology of a real algebraic space curve. The novelties of this algorithm are a new technique to achieve the lifting step which recovers points of the space curve in each plane fiber from several projections and a weaken notion of generic position. As opposed to previous work, our sweep generic position does not require that x-critical points have different x-coordinates. The complexity of achieving this sweep generic position is thus no longer a bottleneck in term of complexity. The bit complexity of our algorithm is O(d^18 + d ^17 t) where d and t bound the degree and the bitsize of the integer coefficients of the defining polynomials of the curve and polylogarithmic factors are ignored. To the best of our knowledge, this improves upon the best currently known results at least by a factor of d 2

    High-dimensional orbital angular momentum entanglement concentration based on Laguerre-Gaussian mode selection

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    Twisted photons enable the definition of a Hilbert space beyond two dimensions by orbital angular momentum (OAM) eigenstates. Here we propose a feasible entanglement concentration experiment, to enhance the quality of high-dimensional entanglement shared by twisted photon pairs. Our approach is started from the full characterization of entangled spiral bandwidth, and is then based on the careful selection of the Laguerre–Gaussian (LG) modes with specific radial and azimuthal indices p and `. In particular, we demonstrate the possibility of high-dimensional entanglement concentration residing in the OAM subspace of up to 21 dimensions. By means of LabVIEW simulations with spatial light modulators, we show that the Shannon dimensionality could be employed to quantify the quality of the present concentration. Our scheme holds promise in quantum information applications defined in high-dimensional Hilbert space

    COVID-19 vaccination coverage among adolescents aged 12–17 years in three provinces of eastern China: A cross-sectional survey, 2021

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    High vaccination coverage is essential to prevent and control the spread of the COVID-19 epidemic. Currently, the real-world acceptance of COVID-19 vaccines among adolescents aged 12–17 years in China has not been reported. We aimed to assess the acceptance rate of COVID-19 vaccination among adolescents in eastern China and to identify factors associated with the intention to get vaccinated against COVID-19. We conduct a cross-sectional questionnaire survey among adolescents from three provinces in the eastern part of China from 16 August to 28 October 2021. The questionnaires were distributed to 2,100 students, and 2,048 students completed the questionnaires. The results showed that 98.4% (2,016/2,048) of adolescents had received at least one dose of the COVID-19 vaccine and 1.6% (32/2,048) declined the vaccination. The participants from rural districts, or whose parents were vaccinated, were more likely to accept the vaccine. The main reason for declining vaccination was worry about vaccine safety (25%). The main adverse event after the vaccination was pain at the injection site. In conclusion, the vaccine coverage rate reached 98.4% among the adolescents in this study, which met the criteria for herd immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The high vaccination rate is beneficial to the prevention and control of the COVID-19 pandemic

    Species responses to changing precipitation depend on trait plasticity rather than trait means and intraspecific variation

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    Trait-based approaches are key to develop mechanistic understanding of differences in plant species performance under environmental change. While mean trait values have been widely used to link functional traits to species performance, the contribution of intraspecific trait variation and trait plasticity remains unclear. Moreover, environmentally induced changes in species biomass are caused by changes in the number of individuals and individual growth rate, both of which should be influenced by trait differences and plasticity. Our goal in this study is to use trait-based information to explain species performance via changes in species abundance and individual weight. We measured the mean, intraspecific variation and plasticity of nine above-ground plant traits, and a further three mean root traits from 10 common species in a precipitation manipulation experiment in semi-arid grassland. We used this trait information to explain differences in the responses of species biomass, abundance and mean individual weight to changing precipitation. Species responses were calculated as the normalised slopes of the regressions between species biomass, abundance and individual weight with the manipulated precipitation amount. We found strong differences in species responses to changing precipitation for species biomass, abundance and mean individual weight. Reduced precipitation decreased biomass, abundance and mean individual weight for some species, but increased them for others. Biomass and mean individual weight of species with resource-acquisitive traits, such as shallow rooted species, showed stronger positive responses to changing precipitation compared to resource-conservative traits, like those with deep roots. For above-ground traits, trait plasticity was the strongest predictor of species responses compared to mean traits and intraspecific trait variation. In addition, trait plasticity regulated changes in species biomass more via changes in species abundance than mean individual weight. These results indicate that trait plasticity is a key driver for determining species-specific responses to changing precipitation and needs more consideration for understanding and predicting ecosystem structure and functioning in future climate scenarios. A free Plain Language Summary can be found within the Supporting Information of this article
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