6,140 research outputs found

    Exogenous Application of Jasmonic Acid Induces Volatile Emissions in Rice and Enhances Parasitism of Nilaparvata lugens Eggs by theParasitoid Anagrus nilaparvatae

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    Jasmonate signaling pathway plays an important role in induced plant defense against herbivores and pathogens, including the emission of volatiles that serve as attractants for natural enemies of herbivores. We studied the volatiles emitted from rice plants that were wounded and treated with jasmonic acid (JA) and their effects on the host-searching behavior of the rice brown planthopper, Nilaparvata lugens (Stål), and its mymarid egg parasitoid Anagrus nilaparvatae Pang et Wang. Female adults of N. lugens significantly preferred to settle on JA-treated rice plants immediately after release. The parasitoid A. nilaparvatae showed a similar preference and was more attracted to the volatiles emitted from JA-treated rice plants than to volatiles from control plants. This was also evident from greenhouse and field experiments in which parasitism of N. lugens eggs by A. nilaparvatae on plants that were surrounded by JA-treated plants was more than twofold higher than on control plants. Analyses of volatiles collected from rice plants showed that JA treatment dramatically increased the release of volatiles, which included aliphatic aldehydes and alcohols, monoterpenes, sesquiterpenes, methyl salicylate, n-heptadecane, and several as yet unidentified compounds. These results confirm an involvement of the JA pathway in induced defense in rice plants and demonstrate that the egg parasitoid A. nilaparvatae exploits plant-provided cues to locate hosts. We explain the use of induced plant volatiles by the egg parasitoid by a reliable association between planthopper feeding damage and egg presenc

    Production of squeezed state of single mode cavity field by the coupling of squeezed vacuum field reservoir in nonautonomous case

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    The dissipative and decoherence properties as well as the asymptotic behavior of the single mode electromagnetic field interacting with the time-dependent squeezed vacuum field reservoir are investigated in detail by using the algebraic dynamical method. With the help of the left and right representations of the relevant hw(4)hw(4) algebra, the dynamical symmetry of the nonautonomous master equation of the system is found to be su(1,1)su(1,1). The unique equilibrium steady solution is found to be the squeezed state and any initial state of the system is proved to approach the unique squeezed state asymptotically. Thus the squeezed vacuum field reservoir is found to play the role of a squeezing mold of the cavity field.Comment: 5 pages, no figure, Revtex

    Influence of Perceived Value on Clients' Behavioural Intention in Online Psychological Counseling

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    This study employed quantitative research methods to survey 400 customers in China who had used online psychological counseling. Subsequently, SmartPLS4.0 was used to conduct structural equation modeling to test the comprehensive relationship between variables. The research demonstrates the role of emotional experience, perceived usefulness, and ease of use in determining user intent. Conversely, there is a negative correlation with perceived cost. The findings suggest that cost plays a significant role in user decision-making when it comes to online psychological counseling. These results provide valuable insight into how users perceive such services and can guide their development

    Study on electromagnetically induced transparency effects in Dirac and VO2_2 hybrid material structure

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    In this paper, we present a metamaterial structure of Dirac and vanadium dioxide and investigate its optical properties using the finite-difference time-domain (FDTD) technique. Using the phase transition feature of vanadium dioxide, the design can realize active tuning of the PIT effect at terahertz frequency, thereby converting from a single PIT to a double PIT. When VO2_2 is in the insulating state, the structure is symmetric to obtain a single-band PIT effect; When VO2_2 is in the metallic state, the structure turns asymmetric to realize a dual-band PIT effect. This design provides a reference direction for the design of actively tunable metamaterials. Additionally, it is discovered that the transparent window's resonant frequency and the Dirac material's Fermi level in this structure have a somewhat linear relationship. In addition, the structure achieves superior refractive index sensitivity in the terahertz band, surpassing 1 THz/RIU. Consequently, the concept exhibits encouraging potential for application in refractive index sensors and optical switches

    Natures of Tcs(2900)T_{cs}(2900) and Tcsˉa(2900)T^a_{c\bar{s}}(2900)

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    Inspired by the states Tcs0(2900)0T_{cs0}(2900)^0, Tcs1(2900)0T_{cs1}(2900)^0, Tcsˉ0a(2900)0T^a_{c\bar{s}0}(2900)^{0} and Tcsˉ0a(2900)++T^a_{c\bar{s}0}(2900)^{++} reported by the LHCb Collaboration, we carry out a systematical investigation on the properties of the ground and PP-wave states [cs][uˉdˉ][cs][\bar{u}\bar{d}] and [cu][sˉdˉ][cu][\bar{s}\bar{d}] with various spin, isospin or UU-spin, and color combinations in a multiquark color flux-tube model. Matching our results with the spin-parity and mass of the states Tcs0(2900)0T_{cs0}(2900)^0 and Tcs1(2900)0T_{cs1}(2900)^0, we can describe them as the compact states [cs][uˉdˉ][cs][\bar{u}\bar{d}] with I(JP)=1(0+)I(J^{P})=1(0^+) and 0(1)0(1^-) in the model, respectively. The ground state Tcs0(2900)0T_{cs0}(2900)^0 is mainly made of strongly overlapped axial-vector [cs]3ˉc[cs]_{\bar{\mathbf{3}}_c} and axial-vector [uˉdˉ]3c[\bar{u}\bar{d}]_{\mathbf{3}_c}. The PP-wave state Tcs1(2900)0T_{cs1}(2900)^0 is dominantly consisted of gradually separated scalar or axial vector [cs]3ˉc[cs]_{\bar{\mathbf{3}}_c} and scalar [uˉdˉ]3c[\bar{u}\bar{d}]_{\mathbf{3}_c} in the shape of a dumbbell. Supposing the states Tcsˉ0a(2900)0T^a_{c\bar{s}0}(2900)^{0} and Tcsˉ0a(2900)++T^a_{c\bar{s}0}(2900)^{++} belong to the same isospin triplet, the mass of the state [[cu]3ˉc[sˉdˉ]3c]1c\left [[cu]_{\bar{\mathbf{3}}_c}[\bar{s}\bar{d}]_ {\mathbf{3}_c}\right ]_{\mathbf{1}_c} with symmetrical UU-spin and JP=0+J^P=0^+ is highly consistent with that of the states Tcsˉ0a(2900)0T^a_{c\bar{s}0}(2900)^{0} and Tcsˉ0a(2900)++T^a_{c\bar{s}0}(2900)^{++} in the model. After coupling two color configurations, the state [cu][sˉdˉ][cu][\bar{s}\bar{d}] is a little lighter than the states Tcsˉ0a(2900)0T^a_{c\bar{s}0}(2900)^{0} and Tcsˉ0a(2900)++T^a_{c\bar{s}0}(2900)^{++}. In addition, we also discuss the properties of other states in the model.Comment: 8 pages, 4 tables, comments are welcom

    An Investigation into the Multifactor Influences on Ecotourism Behavioural Intention, with Satisfaction as a Mediating Variable

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    This study examines the multifactor influencing ecotourism behavioural intention in China from the perspective of ecotourism satisfaction. The study distributed a self-filled questionnaire to 400 tourists who had visited a famous scenic ecotourism spot in China. Use PLS-SEM for structural equation modelling and analysis. The survey results indicate that tourist satisfaction only mediates perceived values, attitudes, and ecotourism behavioural intentions. Subjective norms, perceived value, attitude, and perceived behavioural control all impact tourist satisfaction. This provides theoretical support and management direction for China’s sustainable and healthy ecotourism development
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