31 research outputs found
Analysis of cognitive function and its related factors after treatment in Meniere’s disease
A growing body of research recently suggested the association between vestibular dysfunction and cognitive impairment. Meniere’s disease (MD), a common clinical vestibular disorder, is usually accompanied by hearing loss and emotional stress, both of which may mediate the relationship between vestibule dysfunction and cognition. It is currently unknown whether the cognitive decline in MD patients could improve through treatment and how it relates to multiple clinical characteristics, particularly the severity of vertigo. Therefore, in the present study, the MD patients were followed up for 3, 6, and 12 months after treatment, and the cognitive functions, vertigo symptoms, and related physical, functional, and emotional effects of the patients were assessed using the Montreal Cognitive Assessment (MoCA) and Dizziness Handicap Inventory (DHI), aiming to explore the change in cognition before and after therapy and the correlation with various clinical features. It was found that cognitive decline in MD patients compared to healthy controls before therapy. Importantly, this cognitive impairment could improve after effective therapy, which was related to the severity of vertigo, especially in functional and physical impacts. Our results support the view that vestibular dysfunction is a potentially modifiable risk factor for cognitive decline
A New Method of Blind Source Separation Using Single-Channel ICA Based on Higher-Order Statistics
Methods of utilizing independent component analysis (ICA) give little guidance about practical considerations for separating single-channel real-world data, in which most of them are nonlinear, nonstationary, and even chaotic in many fields. To solve this problem, a three-step method is provided in this paper. In the first step, the measured signal which is assumed to be piecewise higher order stationary time series is introduced and divided into a series of higher order stationary segments by applying a modified segmentation algorithm. Then the state space is reconstructed and the single-channel signal is transformed into a pseudo multiple input multiple output (MIMO) mode using a method of nonlinear analysis based on the high order statistics (HOS). In the last step, ICA is performed on the pseudo MIMO data to decompose the single channel recording into its underlying independent components (ICs) and the interested ICs are then extracted. Finally, the effectiveness and excellence of the higher order single-channel ICA (SCICA) method are validated with measured data throughout experiments. Also, the proposed method in this paper is proved to be more robust under different SNR and/or embedding dimension via explicit formulae and simulations
Unveiling the Impact of Payment Methods on Consumer Behavior: Insights and Future Directions
Technological advancements drive the development of payment methods. This review provides a comprehensive examination of the pervasive influence of payment methods on consumer behavior, referred to as payment method effect. We first examine the multifaceted implications of card payments on consumer spending behaviors, post-consumption behaviors, and broader general behaviors, while also analyzing potential moderators including product type and consumer characteristics. Our review unveils the intricate psychological mechanisms underlying the payment method effect, including reduced pain of paying, primed hedonic mindset, biased perceptions of available resources. Looking forward, we underscore several avenues for future research, particularly in exploring the emerging mobile payment effects, designing practical interventions to mitigate dark sides of payment method effects, and investigating cross-cultural heterogeneity in payment method effect. Our review contributes not only to the theoretical advancement of consumer psychology but also to the development of effective strategies for promoting responsible consumer behavior in an increasingly digitized era
Comparison of multi-objective genetic algorithms for optimization of cascade reservoir systems
Multi-objective genetic algorithms (MOGAs) are widely used for multi-reservoir systems’ optimization due to their high efficiency and fast convergence. However, the computational cost grows exponentially with the expansion of multi-reservoir systems and the increased dimensions of optimization problems, posing a great challenge to multi-reservoir operations. Therefore, it is important to find a suitable and efficient multi-objective algorithm for multi-reservoir system optimization. In this study, three representative MOGAs were selected, namely the Non-dominated Sorting Genetic Algorithm II (NSGA-II), Non-Dominated Sorting Genetic Algorithm III (NSGA-III), and Reference Vector Guided Evolutionary Algorithm (RVEA), and three multi-objective optimization models were then developed accordingly. Numerical experiments were conducted to evaluate the performance of these three algorithms for the optimization of a cascaded reservoir system. The results show that for the two-objective model, the non-dominant size generation rate (NDSGR) of NSGA-II is 1.66 and 4.01 times that of NSGA-III and RVEA, respectively. NSGA-II is more suitable for solving the optimization operation problem with two objectives. Based on the comprehensive evaluation, NSGA-III seems to be more appropriate for more than two objectives. These results emphasize the importance of using appropriate algorithms and provide further insights into the choice of algorithms for the optimization of hydropower systems.
HIGHLIGHTS
Development of MOGAs was reviewed.;
Three representative MOGAs were selected, namely NSGA-II, NSGA-III, and RVEA, and three multi-objective optimization models were then developed accordingly for comparison.;
Numerical experiments were conducted to evaluate the performance of representative MOGAs for optimization of a cascaded reservoir system.
Ultrafast light emission at telecom wavelengths from a wafer-scale monolayer graphene enabled by Fabry-Perot interferences
Ultrafast light emission from monolayer graphene shows attractive potential for developing integrated light sources for next-generation graphene-based electronic-photonic integrated circuits. In particular, graphene light sources operating at the telecom wavelengths are highly desired for the implementation of graphene-based ultrahigh-speed optical communication. Currently, most of the studies on ultrafast light emission from graphene have been performed in the visible spectrum, while studies on ultrafast emission at the telecom wavelengths remain scarce. Here, we present experimental observations of strong ultrafast thermal emission at telecom wavelengths from wafer-scale monolayer graphene. Our results show that the emission spectra can be strongly modified by the presence of the cavity effect to produce an enhanced emission at telecom wavelengths. We corroborate our experimental results with simulations and show that by designing a suitable cavity thickness, one can easily tune the emission profile from visible to telecom wavelength regardless of the pump power. In addition, we demonstrate that the insertion of a monolayer of hexagonal boron nitride between graphene and the substrate helps improve the thermal stability of graphene, thereby providing more than five times enhancement of the ultrafast thermal emission. Our results provide a potential solution for stable on-chip nanoscale light sources with ultrahigh speed modulation.Agency for Science, Technology and Research (A*STAR)Ministry of Education (MOE)National Research Foundation (NRF)Agency for Science, Technology and Research (AME IRG (A2083c0053)); National Research Foundation Singapore (NRF2018-NRF-ANR009 TIGER, NRF-CRP19-2017-01); Ministry of Education - Singapore (AcRF TIER 1 (RG 115/21), AcRF TIER 2 (MOE2018-T2-2-011 (S)))
Strong second-harmonic generation by sublattice polarization in non-uniformly strained monolayer graphene
Abstract Despite the potential of graphene for building a variety of quantum photonic devices, its centrosymmetric nature forbids the observation of second harmonic generation (SHG) for developing second-order nonlinear devices. To activate SHG in graphene, extensive research efforts have been directed towards disrupting graphene’s inversion symmetry using external stimuli like electric fields. However, these methods fail to engineer graphene’s lattice symmetry, which is the root cause of the forbidden SHG. Here, we harness strain engineering to directly manipulate graphene’s lattice arrangement and induce sublattice polarization to activate SHG. Surprisingly, the SHG signal is boosted 50-fold at low temperatures, which can be explained by resonant transitions between strain-induced pseudo-Landau levels. The second-order susceptibility of strained graphene is found to be larger than that of hexagonal boron nitride with intrinsic broken inversion symmetry. Our demonstration of strong SHG in strained graphene offers promising possibilities for developing high-efficiency nonlinear devices for integrated quantum circuits
Safety Evaluation of Plain Concrete Lining Considering Deterioration and Aerodynamic Effects
With an increase in the service time of high-speed railway tunnels, various defects caused by construction-quality defects in the secondary lining begin to appear. How to evaluate the safety of such tunnels and take countermeasures is very important for the safe operation of tunnels. Based on the load-structure method and a numerical simulation, this paper studied the short-term and long-term safety of the missing section of anti-crack reinforcement mesh in the plain concrete lining of a high-speed railway mountain tunnel. The short-term safety evaluation considered the influence of negative pressure caused by aerodynamic effects. The long-term safety evaluation considered the combined influence of the surrounding rock and concrete deterioration and the negative pressure and concrete fatigue damage caused by aerodynamic effects. The results showed that under the negative pressure generated by aerodynamic effects, the minimum tensile safety factor of the lining in the defective section increased by 3.8%, while the minimum compressive safety factor of the lining decreased by 7.9%. The negative pressure generated by the aerodynamic effects had little impact on the short-term safety of the lining in the defective section. During the long-term safety evaluation, the overall safety of the defective section decreased significantly, and the minimum tensile and minimum compressive safety factors of the lining decreased by 59.4% and 66.8%, respectively. The calculation results for the initial design do not meet the long-term design requirements and cannot guarantee the long-term safe operation of the tunnel. Finally, two new strengthening methods of galvanized steel mesh-short bolts and galvanized corrugated steel plate-short bolts were proposed to strengthen the defective section of the concrete lining, so as to improve the ultimate bearing capacity and toughness of the plain concrete lining structure
Layered Double Hydroxide–Carbon Dot Composite: High-Performance Adsorbent for Removal of Anionic Organic Dye
It
would be of significance to design a green composite for efficient
removal of contaminants. Herein, we fabricated a facile and environmentally
friendly composite via direct assembly of surface passivated carbon
dots with abundant oxygen-containing functional groups on the surface
of the positively charged layered double hydroxide (LDH). The resulting
LDH–carbon dot composites were characterized by X-ray diffraction
(XRD), Fourier transformed infrared (FTIR) spectroscopy, high resolution
transmission electron microscopy (HRTEM), scanning electron microscopy
(SEM), and N<sub>2</sub> adsorption–desorption technique. The
adsorption performances of the resulting LDH–carbon dot composites
were evaluated for the removal of anionic methyl blue dye. Taking
advantage of the combined benefits of LDH and carbon dots, the as-prepared
composites exhibited high uptake capability of methyl blue (185 mg/g).
The adsorption behavior of this new adsorbent fitted well with Langmuir
isotherm and the pseudo-second-order kinetic model. The reasons for
the excellent adsorption capacity of methyl blue on the surface of
the LDH–carbon dot hybrid were further discussed. A probable
mechanism was speculated to involve the cooperative contributions
of hydrogen bonding between methyl blue and carbon dots and electrostatic
attraction between methyl blue and LDH, in the adsorption process.
This work is anticipated to open up new possibilities in fabricating
LDH–carbon dot materials in dealing with anionic dye pollutants