2,434 research outputs found

    Study on dynamic response of track structures under a variable speed moving harmonic load

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    Basing on the dynamic response characteristics of the periodic structure under a moving harmonic load in frequency domain and the superposition principle, the dynamic response of track structure under variable speeds moving harmonic load is investigated. Firstly, the track is simplified as an Euler beam model periodically supported by continuous discrete point, the dynamic differential equation of vertical vibration for the track structure is formulated. Secondly, for convenience of analysis, the analytical expression for the amplitude-frequency response of any point on the track structure under the moving harmonic load is derived in frequency domain. Based on the theory of the infinite periodic structure, the dynamic responses of the track structure under the variable speed moving harmonic load are analyzed theoretically. Finally, the influences of velocity and acceleration on the dynamic response of track structure are numerically analyzed in detail. The research results indicate that the amplitude-frequency response peaks of the track under moving harmonic load with variable and constant speeds occur near the excitation frequency. The displacement response of the track increases slightly with increase of the acceleration, and the variation trend of dynamic response is basically similar. The vibration displacement response of the rail can be effectively improved by increasing the initial velocity of the moving harmonic load, while the peak value of amplitude-frequency response remained constant

    Tensor coupling effects on spin symmetry in anti-Lambda spectrum of hypernuclei

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    The effects of ΛˉΛˉω\bar\Lambda\bar\Lambda\omega-tensor coupling on the spin symmetry of Λˉ\bar{\Lambda} spectra in Λˉ\bar{\Lambda}-nucleus systems have been studied with the relativistic mean-field theory. Taking 12^{12}C+Λˉ\bar{\Lambda} as an example, it is found that the tensor coupling enlarges the spin-orbit splittings of Λˉ\bar\Lambda by an order of magnitude although its effects on the wave functions of Λˉ\bar{\Lambda} are negligible. Similar conclusions has been observed in Λˉ\bar{\Lambda}-nucleus of different mass regions, including 16^{16}O+Λˉ\bar{\Lambda}, 40^{40}Ca+Λˉ\bar{\Lambda} and 208^{208}Pb+Λˉ\bar{\Lambda}. It indicates that the spin symmetry in anti-lambda-nucleus systems is still good irrespective of the tensor coupling.Comment: 12 pages, 3 figures

    3-(1,3-Dithio­lan-2-yl­idene)-1-(4-meth­oxy­phen­yl)pyridine-2,4(1H,3H)-dione

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    In the title compound, C15H13NO3S2, the dithiol­ane ring adopts a twisted conformation. The mol­ecule exhibits a V-shaped conformation, with a dihedral angle of 79.05 (7)° between the benzene ring and the pyridine ring. In the crystal, C—H⋯O inter­actions are observed

    Recombination frequencies between cultivated soybean (Glycine max) and its wild relative Glycine soja based on molecular marker analysis

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    Close relatives of cultivated crops provide an invaluable source of genetic variation in crop improvement and exploiting such variation often forms a critical part in a breeding program. The usability of the wild soybean Glycine soja was investigated in this study by analyzing populations derived from two wide crosses between a common cultivar and two different G. soja accessions using simple sequence repeat (SSR) markers. Consistent reductions in recombination frequencies were not detected in either of these two wide crosses and the results does not seem to be confined to the particular populations or the wild genotypes used. In variance with previous reports that domestication-related traits are often controlled by one or two major loci, these recombination results strongly indicate that linkage drag should not be a major concern in transferring genes from the wild taxon into the cultigen, although backcross would still be required to minimize undesirable chromatins.Keywords: Glycine max, Glycine soja, linkage drags, recombination frequency, molecular markersAfrican Journal of Biotechnology Vol. 12(22), pp. 3522-352

    Symmetric multiparty-controlled teleportation of an arbitrary two-particle entanglement

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    We present a way for symmetric multiparty-controlled teleportation of an arbitrary two-particle entangled state based on Bell-basis measurements by using two Greenberger-Horne-Zeilinger states, i.e., a sender transmits an arbitrary two-particle entangled state to a distant receiver, an arbitrary one of the n+1n+1 agents via the control of the others in a network. It will be shown that the outcomes in the cases that nn is odd or it is even are different in principle as the receiver has to perform a controlled-not operation on his particles for reconstructing the original arbitrary entangled state in addition to some local unitary operations in the former. Also we discuss the applications of this controlled teleporation for quantum secret sharing of classical and quantum information. As all the instances can be used to carry useful information, its efficiency for qubits approaches the maximal value.Comment: 9 pages, 3 figures; the revised version published in Physical Review A 72, 022338 (2005). The detail for setting up a GHZ-state quantum channel is adde

    The Effect of Ozone-Electric Treatment on the Enrichment and Transfer of Heavy Metal Cu in Sludge

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    In order to explore a safe, effective way to use sludge as agricultural fertilizer it is necessary to effectively separate and remove the heavy metals embedded in sludge. In the study, the ozone-electric two-stage treatment was used to transform heavy metal copper in the sludge, and then the treated sludge was used for maize production and the transferring of Cu in cultivation medium and plants, and the enrichment effect of Cu in plant were investigated. According to composition of culture substance, five treatments were set in maize planting experiments: CK, Agricultural soil without addition; T1, Agricultural soil supplemented with raw sludge; T2, Agricultural soil treated with ozone sludge; T3, Agricultural soil with ozone treated and electric treated sludge; T4, Agricultural soil added with common organic fertilizer. The results showed that in different treatments, the Cu content of organs showed the order of root> stem> leaf> cob> grain. Comparing root Cu content, the lowest was in T1 treatment, which was 11.60 mg/kg, while the lowest of grain Cu content was found in CK treatment, which was 1.36 mg/kg. In the upper, middle and lower soil layers, the highest and lowest Cu content was in T4 and CK, respectively. In both middle and lower soil layers, the Cu content of T1, T2 and T3 sludge treatments had a trend of T1>T2>T3; the difference of the Cu enrichment ability between different organs is not significant in the same soil layer. From each treatment, the Cu enrichment ability of plant of CK was higher than that of other treatments. According to the ability of Cu transferring to the above-ground part of plant, treatments are ranked as CK>T3>T4>T1>T2. The transferring of Cu from soil to plant was mainly affected by fertilizer level and the transferring rate of Cu from soil to stem, leaf and root was relatively high, but it was hardly affected by sludge. In summary, after ozone-electro treatment, the application of sludge does not significantly affect the Cu content in maize, and the Cu content in each treatment does not exceed the limit value of agricultural production

    Long-term unmet needs after stroke:systematic review of evidence from survey studies

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    OBJECTIVES: To synthesise evidence on longer term unmet needs perceived by stroke survivors, and psychometric properties of the tools used to evaluate unmet care needs after stroke. DESIGN: Systematic review. SETTING: Community or patients' home. PARTICIPANTS: Stroke survivors. METHODS: We searched PubMed, PsycINFO, CINAHL, EMBASE from inception to 31 March 2018 to identify survey studies that evaluated unmet needs perceived by stroke survivors after hospital discharge. Reported unmet needs were categorised under three domains: body functioning, activity/participation and environmental factors. Ranges of prevalence rates of unmet needs reported in studies were presented. RESULTS: We included 19 eligible studies, with considerable heterogeneity in patients, survey methods and results. Psychometric properties of two stroke-specific tools were formally evaluated, indicating their moderate reliability and content/concurrent validity. The median number of reported unmet needs per stroke survivor was from two to five, and the proportion of stroke survivors with at least one unmet needs was on average 73.8% (range 19.8%- 91.7%). Unmet needs perceived by stroke survivors included 55 records of unmet body functioning needs, 47 records of unmet activities/participatory needs and 101 records of unmet environmental needs. Common unmet service needs were unmet information needs (3.1%- 65.0%), transport (5.4%-53.0%), home help/personal care (4.7%-39.3%) and therapy (2.0%-35.7%). CONCLUSIONS: The prevalence of unmet long-term needs is high among stroke survivors, and there is considerable heterogeneity in type and frequency of specific unmet needs. More research is required to link regular assessment of long-term unmet needs of stroke survivors with the provision of cost-effective patient-centred health and social care services

    Poly[[aqua­(1-naphthyl­acetato)cadmium(II)]-μ3-pyridin-3-olato]

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    In the title complex, [Cd(C5H4NO)(C12H9O2)(H2O)]n, each CdII atom is coordinated by two carboxylate O atoms from one 1-naphthyl­acetate ligand, two hydroxyl O atoms from two pyridin-3-olate ligands, one N atom from another pyridin-3-olate ligand and one water mol­ecule, and displays a distorted octa­hedral coordination geometry. The compound forms infinite chains of pyridin-3-olate ligands bridging 1-naphthyl­acetate–CdII units parallel to the b axis, with a Cd⋯Cd separation of 3.578 (2) Å. The chains are further self-assembled into a supra­molecular network through inter­molecular O—H⋯O hydrogen-bonding inter­actions

    Studies on Anti-Depressant Activity of Four Flavonoids Isolated from Apocynum venetum Linn (Apocynaceae) Leaf in Mice

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    Purpose: To investigate the anti-depressant activity of kaempferol, quercetin, kaempferol-3-O-β-Dglucose and quercetin-3-O-β-D-glucose isolated from Apocynum venetum Linn. (Apocynaceae) leaf and their mechanisms of action.Methods: The four flavonoids were isolated from Apocynum venetum leaf by chromatography. Mice were divided into vehicle, fluoxetine, kaempferol, quercetin, kaempferol-3-O-β-D-glucose and quercetin- 3-O-β-D-glucose groups (n = 10). Forced swimming (FST), tail suspension (TST) and locomotor activity (LAT) tests were used to evaluate the effects of the four flavonoids (0.35 mM/kg) on immobility time, monoamine neurotransmitters, viz, norepinephrine (NE), dopamine (DA) and 5-hydroxytryptamine (5- HT), as well as on the metabolite (5-HIAA) in mice brain and central nervous system (CNS) with the aid of video camera, HPLC-ECD and activity-monitoring system.Results: The four flavonoids significantly (p < 0.05) reduced mice immobility time (72.58 - 90.24; 52.58 - 70.24 s), 5-HIAA levels (940.8 - 1244.7; 880.8 - 1164.1 ng/g) and 5-HIAA/5-HT ratio (1.77 - 4.76; 1.83 - 4.16), but increased NE, DA and 5-HT levels (238.7 - 405.7, 308.4 - 528.1, 261.4 - 531.9; 243.9 - 423.6, 296.7 - 534.9, 279.8 - 481.4 ng/g) in FST and TST, compared with control group (146.18, 126.18 s; 1363.4, 1240.9 ng/g; 7.43, 6.16; 138.4, 235.4, 183.4 and 143.7, 218.6, 201.4 ng/g). The effects of the four flavonoids on the above indices were significant (p < 0.05) and positively related to their polarity. They had no CNS-stimulating effects in LAT.Conclusion: The anti-depressant activities of the four flavonoids are positively related to their polarity, and the mechanisms may be due to increased NE, DA and 5-HT and reduced 5-HT metabolism.Keywords: Kaempferol, Quercetin, Forced swimming test, Tail suspension test, Locomotor activity test, Neurotransmitter
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