A quantitative review of the effects of Se application on the reduction of Hg concentration in plant: a meta-analysis

Mercury (Hg) is a highly toxic heavy metal entering the human body through the food chain after absorption by plant. Exogenous selenium (Se) has been suggested as a potential solution to reduce Hg concentration in plants. However, the literature does not provide a consistent picture of the performance of Se on the accumulation of Hg in plant. To obtain a more conclusive answer on the interactions of Se and Hg, 1,193 data records were collected from 38 publications for this meta-analysis, and we tested the effects of different factors on Hg accumulation by meta-subgroup analysis and meta-regression model. The results highlighted a significant dose-dependent effect of Se/Hg molar ratio on the reduction of Hg concentration in plants, and the optimum condition for inhibiting Hg accumulation in plants is at a Se/Hg ratio of 1–3. Exogenous Se significantly reduced Hg concentrations in the overall plant species, rice grains, and non-rice species by 24.22%, 25.26%, and 28.04%, respectively. Both Se(IV) and Se(VI) significantly reduced Hg accumulation in plants, but Se(VI) had a stronger inhibiting effect than Se(IV). Se significantly decreased the BAFGrain in rice, which indicated that other physiological processes in rice may be involved in restricting uptake from soil to rice grain. Therefore, Se can effectively reduce Hg accumulation in rice grain, which provides a strategy for effectively alleviating the transfer of Hg to the human body through the food chain

Class-Specific Attention (CSA) for Time-Series Classification

Most neural network-based classifiers extract features using several hidden layers and make predictions at the output layer by utilizing these extracted features. We observe that not all features are equally pronounced in all classes; we call such features class-specific features. Existing models do not fully utilize the class-specific differences in features as they feed all extracted features from the hidden layers equally to the output layers. Recent attention mechanisms allow giving different emphasis (or attention) to different features, but these attention models are themselves class-agnostic. In this paper, we propose a novel class-specific attention (CSA) module to capture significant class-specific features and improve the overall classification performance of time series. The CSA module is designed in a way such that it can be adopted in existing neural network (NN) based models to conduct time series classification. In the experiments, this module is plugged into five start-of-the-art neural network models for time series classification to test its effectiveness by using 40 different real datasets. Extensive experiments show that an NN model embedded with the CSA module can improve the base model in most cases and the accuracy improvement can be up to 42%. Our statistical analysis show that the performance of an NN model embedding the CSA module is better than the base NN model on 67% of MTS and 80% of UTS test cases and is significantly better on 11% of MTS and 13% of UTS test cases.Comment: 12 page

A Residual-Based Kernel Regression Method for Image Denoising

We propose a residual-based method for denoising images corrupted by Gaussian noise. In the method, by combining bilateral filter and structure adaptive kernel filter together with the use of the image residuals, the noise is suppressed efficiently while the fine features, such as edges, of the images are well preserved. Our experimental results show that, in comparison with several traditional filters and state-of-the-art denoising methods, the proposed method can improve the quality of the restored images significantly

Manipulating classical and nonclassical light with cold atoms

The light wave propagating in a dispersive medium can be formularized as electromagnetic (EM) fields or quantized as a pair of Hermitian operators. The fascinating optical phenomena display classical and nonclassical properties, depending on whether they can be described by the classical EM field theory. A cold atomic ensemble with neligible inhomogenous Doppler broadening is ideal to explore the interaction between light and matter. A typical problem in classical pulse propagation is optical transients, which induced by rapid response of dispersive medium to the sudden change of the driving radiation fields. With cold atoms confined in the two-dimensional magneto-optical trap, whose optical depth is controllable in our system, optical precursor and free-induction decay both classified as optical transients are observed in a single experiment with different conditions. Moreover, the information velocity limit is verified in superluminal medium, with the observation and analysis of precursors. Characterized with narrow linewidth and long coherence time, paired photons generated from cold atomic ensemble in four-wave mixing process possess irreplaceable advantage in quantum optics area. Temporal modulation of narrow-band paired photons can be achieved by directly modulating the generated photons or by modulating the classical control fields. After successfully reshaping the temporal waveform of the paired photons, heralded single photon source is well prepared for studying the propagation of nonclassical single photon in dispersive medium. The speed limit imposed by Einstein Causality principle is firstly experimentally verified on single photon level

Structural color in the scales of blue-banded bees

The iridescent colors of the blue-banded bee (Aphrodita sp.) come from the bands of scales on their backs. Observed in optical microscope, the scales are typically 100μm x 20μm, with bright greenish and dark bands arranged alternately over the whole scale. Electron microscope images of the cross-section along the axis of scale show that arrays of air tubes are embedded orderly in the chitin matrix composing each scale. The submicron air tubes, mostly aligned along one direction, are well organized in particular periodic structure, which can be modeled as two-dimensional photonic crystal. Viewing from the plane of periodicity, the air tubes are many hexagonal cells oriented in a certain direction. There are mainly two kinds of hexagonal arrangement found: Orientation 1 and 2, corresponding to ΓM and ΓK directions along normal incident wave vector. Spectroscopic measurement with spatial resolution of several micrometers is used to demonstrate the UV and visible wavelength range spectra of two independent modes of polarized light, TE and TM modes. The obtained experimental spectra are then compared with theoretical calculation based on two orientations of air tubes model, to show correspondence between two color regions and two orientations. Irregularities occurred in periodic structure are also found to affect the spectra and optical images of the bee scale. Experiments are designed to study and evaluate the contribution of photonic band gap effect and guided resonance effect to structural colors

Optical Precursors in Slow and Fast Light Media

We observe optical precursors generated from slow and fast light cold atomic media. Using constructive interference between sequenced precursors, we produce optical transient pulses with peak powers of about 9 times the input power. © OSA/ANIC/IPR/Sensors/SL/SOF/SPPCom/2011

A study of the effect of population aggregation on common prosperity: Evidence from 283 Chinese cities.

More than 40 years of urbanization in China has brought rapid economic growth, but the uneven development of region and how to achieve common prosperity through urbanization remain a serious concern. This paper analyzes the effect of the urbanization mode of population aggregation in central cities on common prosperity in China. Using panel data of 283 cities from 2004 to 2019, the study constructs a common prosperity index based on the coupling coordination degree of economy, ecology, and society. The Spatial Durbin Model is used to analyze the influence of population aggregation in central cities on common prosperity and the moderating effect of financial self-sufficiency rate. The results show that population aggregation in central cities has a positive effect on common prosperity. There is also a spatial spillover effect, but the impact exhibits an inverted U-shaped characteristic. Moreover, the fiscal self-sufficiency rate has a negative moderating impact on the effect of population aggregation on common prosperity in the early stage, but a positive moderating impact in the later period. This paper concludes by suggesting that the government should promote urbanization, control the size of large cities, accelerate the reform of household registration, and pay attention to the coordinated development of economy, society, and ecology to promote the realization of common prosperity

A Macroscopic Strength Criterion for Isotropic Metals Based on the Concept of Fracture Plane

Although the linear Mohr–Coulomb criterion is frequently applied to predict the failure of brittle materials such as cast iron, it can be used for ductile metals too. However, the criterion has some significant deficiencies which limit its predictive ability. In the present study, the underlying failure hypotheses of the linear Mohr–Coulomb criterion were thoroughly discussed. Based on Mohr’s physically meaningful concept of fracture plane, a macroscopic strength criterion was developed to explain the failure mechanism of isotropic metals. The failure function was expressed as a polynomial expansion in terms of the stresses acting on the fracture plane, and the quadratic approximation was employed to describe the non-linear behavior of the failure envelope. With an in-depth understanding of Mohr’s fracture plane concept, the failure angle was regarded as a generalized strength parameter in addition to the failure stress (i.e., the conventional basic strength). The undetermined coefficients of the non-linear failure function were calibrated by the strength parameters obtained from the common uniaxial tension and compression tests. Theoretical and experimental assessment for different types of isotropic metals validated the effectiveness of the proposed criterion in predicting material failure

Relationship between economic growth and income gap.

Relationship between economic growth and income gap.</p