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The additive model is a popular nonparametric regression method due to its ability to retain modeling flexibility while avoiding the curse of dimensionality. The backfitting algorithm is an intuitive and widely used numerical approach for fitting additive models. However, its application to large datasets may incur a high computational cost and is thus infeasible in practice. To address this problem, we propose a novel approach called independence-encouraging subsampling (IES) to select a subsample from big data for training additive models. Inspired by the minimax optimality of an orthogonal array (OA) due to its pairwise independent predictors and uniform coverage for the range of each predictor, the IES approach selects a subsample that approximates an OA to achieve the minimax optimality. Our asymptotic analyses demonstrate that an IES subsample converges to an OA and that the backfitting algorithm over the subsample converges to a unique solution even if the predictors are highly dependent in the original big data. The proposed IES method is also shown to be numerically appealing via simulations and a real data application.

The rising demand for online video content has fostered one of the fastest-growing markets as evidenced by the popularity of platforms like TikTok. Because video content is often difficult to create, platforms have attempted to leverage recent advancements in artificial intelligence (AI) to help creators with their video creation process. However, surprisingly little is known about the effects of AI on content creators’ productivity and creative patterns in this emerging market. Our paper investigates the adoption impact of AI-generated voice – a generative AI technology creating acoustic artifacts – on video creators by empirically analyzing a unique dataset of 4,021 creators and their 428,918 videos on TikTok. Utilizing multiple audio and video analytics algorithms, we detect the adoption of AI voice from the massive video data and generate rich measurements for each video to quantify its characteristics. We then estimate the effects of AI voice using a difference-in-differences model coupled with look-ahead propensity score matching. Our results suggest that the adoption of AI voice increases creators’ video production and that it induces creators to produce shorter videos with more negative words. Interestingly, creators produce more novel videos with less self-disclosure when using AI voice. We also find that AI-voice videos received less viewer engagement unintendedly. Our paper provides the first empirical evidence of how generative AI reshapes video content creation on online platforms, which provides important implications for creators, platforms, and policymakers in the digital economy.

The cathode in the magnetron should have good secondary emission property and a certain thermionic property. In this article, ZrH2 was added as an activator to obtain rare earth-doped tungsten matrix impregnated cathode to improve the emission property. Cathodes with ZrH2 (Y15-411-Zr cathode) or without ZrH2 (Y15-411 cathode) were prepared by a spray drying method combined with high-temperature sintering in dry hydrogen atmosphere. The emission properties and emission mechanism have been studied. The results showed that thermionic emission performance and secondary emission performance of Y15-411-Zr cathode are 3.4 times and 1.2 times higher than those of Y15-411 cathode, respectively. With the addition of ZrH2, yttrium was produced during activating process, which contributed to the better emission properties of Y15-411-Zr cathode. Furthermore, the work function of barium and oxygen adsorbed on yttrium oxide and yttrium surface was calculated using the first principle. The results showed that the lowest work function of Ba-O absorbed on Y2O3 and Y is 1.9 and 1.6 eV, respectively.

A wideband filtering dielectric patch (DP) antenna with reconfigurable bandwidth is investigated in this paper. Adjusting the aspect ratio of the DP resonator can make the high-order TE121 mode close to the dominate TM101 mode to facilitate the design of wideband filtering DP antenna. Meanwhile, the high-order TM111 mode is adjacent to the TE121 mode and then used as a non-excitation and non-radiation mode for producing an upper band-edge radiation null. On this basis, two slots with different sizes in parallel are introduced into the ground plane to excite the DP resonator, resulting in a lower band-edge radiation null, which sharpens the lower band-edge roll off. A pair of slits between the two coupling slots are incorporated and the varactor diodes are loaded on the slits to tune the electrical distance of the coupling slots, thereby electrically controlling the frequency of the lower band-edge radiation null. In this way, the fractional bandwidth (FBW) of the resultant filtering antenna can be flexibly tuned from 21% to 15.3%. A prototype has been designed, fabricated, and measured. Reasonable agreement was obtained between the simulated and measured results.

We study the problem of off-policy evaluation (OPE) for episodic Partially Observable Markov Decision Processes (POMDPs) with continuous states. Motivated by the recently proposed proximal causal inference framework, we develop a non-parametric identification result for estimating the policy value via a sequence of so-called V-bridge functions with the help of time-dependent proxy variables. We then develop a fitted-Q-evaluation-type algorithm to estimate V-bridge functions recursively, where a non-parametric instrumental variable (NPIV) problem is solved at each step. By analyzing this challenging sequential NPIV problem, we establish the finite-sample error bounds for estimating the V-bridge functions and accordingly that for evaluating the policy value, in terms of the sample size, length of horizon and so-called (local) measure of ill-posedness at each step. To the best of our knowledge, this is the first finite-sample error bound for OPE in POMDPs under non-parametric models.

As the performance of vacuum electron devices is essentially governed by the properties of their cathodes, developing efficient and durable thermionic cathode is necessary and highly desired to meet the boosting requirements of vacuum electron devices. This review summarized the progress made in the past decades with a detailed discussion on the occurred various thermionic cathodes and their features, and the understandings of the correlation between the emission properties and the composition, where structure and synthesis method are well illustrated. Furthermore, dispenser cathodes with novel structures and emission mechanism are highlighted to indicate the recent achievement in this area of research, and Sc-cathode is considered as a promising candidate for the next-generation vacuum electron devices due to the greatly improved efficiency. However, challenges still exist to meet the ever-growing demands of thermionic cathode with collaborative requirement of high performance, easy fabrication and inadequate reproducibility.

Functional data analysis, which handles data arising from curves, surfaces, volumes, manifolds and beyond in a variety of scientific fields, is a rapidly developing area in modern statistics and data science in the recent decades. The effect of a functional variable on an outcome is an essential theme in functional data analysis, but a majority of related studies are restricted to correlational effects rather than causal effects. This paper makes the first attempt to study the causal effect of a functional variable as a treatment in observational studies. Despite the lack of a probability density function for the functional treatment, the propensity score is properly defined in terms of a multivariate substitute. Two covariate balancing methods are proposed to estimate the propensity score, which minimize the correlation between the treatment and covariates. The appealing performance of the proposed method in both covariate balance and causal effect estimation is demonstrated by a simulation study. The proposed method is applied to study the causal effect of body shape on human visceral adipose tissue.

菰（Zizania latifolia）是长江中下游流域常见的挺水植物.为了解菰在野外的扩张和退化机制，本研究通过模拟实验分析了不同时期菰幼苗对短期淹没的形态学响应.实验共选择株高36和70 cm两种幼苗，设计不淹没、50%淹没和100%淹没3个处理.研究结果表明：两组菰幼苗地上部分的形态学响应有一定差异.在100%淹没处理下，36 cm幼苗组株高最低，茎粗和最大叶宽均显著低于其他两个处理；而70 cm幼苗组在不淹没处理下株高最低，茎粗和最大叶宽在50%和100%淹没处理下均无显著差异.两组菰幼苗根系的形态学响应也不一致.36 cm幼苗组，100%淹没处理组的所有6个根系指标均与其他两种处理有显著差异；70 cm幼苗组，不淹没处理组的6个根系指标均与其他两种处理有显著差异.随着淹没深度的增加，两组菰幼苗总生物量和根茎比均逐渐下降；但36 cm幼苗组在100%淹没处理下总生物量和根茎比均显著低于其他两个处理，而70 cm幼苗组在50%和100%淹没处理下却无显著差异.综合以上分析，本研究结果表明随着菰幼苗的生长，其对淹没的形态学响应能力增强.本研究结果对长江中下游湖泊菰的生态调控具有重要意义.

Obesity is gaining increasing attention in modern society since it is associated with various health issues. The visceral adipose tissue (VAT) deposits around the abdominal organs and is considered an extremely important indicator of health risk. VAT can be assessed through magnetic resonance imaging (MRI) or computed tomography (CT) accurately, but the cost is prohibitive. Shape-based body composition prediction has become a promising topic thanks to the prevalence of commodity optical body scan systems, from which numerous anthropometries can be extracted automatically. In this paper, we propose an innovative shape-based hybrid VAT prediction model. The most appealing benefit of our method is to robustly handle the lack of knowledge about gender and demographics. First, we train a baseline VAT prediction model for each gender separately. Second, we train a classifier to predict the gender likelihood and a classifier to predict the shape likelihood of being overestimated in VAT baseline prediction. Third, we integrate the gender likelihood and shape likelihood into the baseline models to derive one hybrid VAT prediction model. We compare our prediction model with other state-of-the-art VAT prediction methods. The result shows that our method outperforms the comparison methods by 21.8% on average.

Fish assemblage will change along with the river habitat environment. In order to find the response degree of fish assemblage to fish culture within low-head-dam water,two low-head dams( including the upstream and downstream dams) of the Wulong River( a tributary of the lower reach of the Yangtze River,China) were selected as sampling sites,where the habitat variables,the fish diversity and fish assemblage structure were surveyed for 6 times from 2013 to 2014 in these wadeable reaches of the sampling sites. A total of 24 fish species which belong to 5 orders,21 genera and 24 species were caught,with dominant Cyprinidae accounting for 58. 3% of the total. After an analysis on the influences of temporal changes and local habitat conditions upon the fish assemblage,seasonal factors were found to have no apparent effect on the fish assemblage structure. The spatial location( the upstream dam or the downstream dam) affected the assemblage's structural differences significantly,which were determined by the abundance of Hemiculter leucisculus,Abbottina rivularis,Rhodeus sinensis,Acheilognathus macropterus in the upstream site,and the abundance of Gambusia affinis in downstream site. Besides,all the three habitat variables including dissolved oxygen,conductivity and current velocity exerted a great impact on the fish assemblage. The differences in habitat environment bring about some great influences on the fish assemblage,showing in the dramatic decrease of capture weight,quantity,density and diversity of fish in the sampling sites of the downstream dam,which are probably caused by the fish culture within the low-head dam.

Y5247 (development code no.), a quinone-outsider-inhibitor (QoI), is a novel fungicide with a broad-spectrum of fungicidal activity against plant filamentous fungi, including B. cinerea. Compared to azoxystrobin, Y5247 had a stronger inhibitory effect on mycelial growth of B. cinerea. The baseline sensitivity of 100 strains showed the EC50 values for Y5247 inhibiting mycelial growth of B. cinerea ranged from 0.0033 to 0.3921 μg/mL with a mean of 0.0859 (±0.0788) μg/mL and the frequency distribution of EC50 values was unimodal. Mutants with stable resistance to Y5247 were not obtained following exposure to ultraviolet light or chemical mutagenesis. However, strains resistant to Y5247 were collected from greenhouses where other QoI fungicides had frequently been sprayed to control gray mold of strawberry. Among the Y5247-resistant strains, EC50 values for Y5247 and other QoIs, including azoxystrobin, kresoxim-methyl and pyraclostrobin, were positively correlated. No cross-resistance was detected between Y5247 and the other fungicides with different modes of action such as carbendazim, diethofencarb, boscalid, fluazinam, procymidone, and fludioxonil. The Y5247-resistant strains showed comparable fitness in mycelial growth, sporulation and pathogenicity to that of Y5247-sensitive strains. The risk of B. cinerea developing resistance to Y5247 was assessed as high. Analysis of cytb in B. cinerea showed that all the Y5247-sensitive and resistant strains carried the type II cytb (which lacks the intron Bcbi-143/144) and the point mutation G143A occurred in all the resistant strains tested.

SYP-1620, a quinone-outside-inhibitor (QoI), is a novel broad-spectrum fungicide. In this study, 108 isolates of Botrytis cinerea from different geographical regions in Jiangsu Province of China were characterized for baseline sensitivity to SYP-1620. The curves of baseline sensitivity were unimodal with a mean EC50 value of 0.0130±0.0109 μg/mL for mycelial growth, 0.01147±0.0062 μg/mL for spore germination, respectively. The biological characterization of SYP-1620 against B. cinerea was determined in vitro. The results indicated that SYP-1620 has a strong inhibiting effect on spore germination, mycelial growth, and respiration. The protective and curative test of SYP-1620 suggested that protective effect was better than curative either on strawberry leaves or on cucumber leaves in vivo. In addition, the biological characterization of SYP-1620-resistant mutants of B. cinerea was investigated. SYP-1620 has no cross-resistance with other types of fungicide. Compared to the sensitive isolates, the resistant mutants had lower mycelial growth and virulence but not differ in mycelial dry weight. Sequencing indicated that SYP-1620 resistance was associated with a single point mutation (G143A) in the cytochrome b gene.

Bamboo keyboards made from bamboo panels are exposed to the influence of mold infection, hygrothermal environment and repeated wear. Mold resistance and hygrothermal aging properties of bamboo keyboard under different treatments were investigated. The abrasion resistance was experimentally studied and compared between bamboo keyboard and plastic keyboard. The results indicated that the bamboo keyboard treated with H2O2 exhibited the best mold resistance, followed by that treated with varnish, and then came the ones with mildew preventive treatment and the control specimens. Although hardly visible to the naked eye after 4 weeks of mold infection test, mold was observed on most plastic keyboards through microscopic examination. For aging test, the shrinkage ratio of bamboo keystroke was 0.34, 0.46 and 0.62 % after high and low temperature (HLT) treatment, while the swelling ratio was 0.01, 1.14 and 1.93 % after constant temperature and humidity (CTH) treatment, respectively. Similar trend in the ratio of dimensional change was observed in terms of both drying shrinkage and hydroscopic swelling: thickness direction > perpendicular-to-grain direction > grain direction. By manual observation, the bamboo keyboard had an advantage over plastic keyboards in terms of the adaptability to an environment of changing temperature. For abrasion test, the wear point of bamboo keyboard was 650 r and that of plastic 150 r indicating that bamboo keyboards performed better in terms of abrasion resistance than plastic ones.

The present paper dealt with the impacts of water level fluctuations on the lakeshore substrate environments of the shal- low lakes in the middle and lower reaches of the Yangtze River. The results showed that substrate environments changed greatly with the elevation gradients. Moisture contents of substrate decreased as the elevation increased,and pH value changed little, while contents of organic matter,total nitrogen and total phosphorus in substrate increased at first and then decreased. Also,sub- strate environments showed clear seasonal dynamics. Analyses showed that the amplitude of water level fluctuations,submergence depth,and duration of high water level had great impacts on the substrates. The coefficients of variation of substrate parameters were the largest in the medium amplitude,indicating that the highest heterogeneity of substrate occurred under such a condition. Substrate nutrients would be lost at an increasing pace with the increase of time and depth submerged during summer. If the dura- tion of high water level was long,the pH values would be changed greater and the nutrients would be lost faster. Our results offered a scientific foundation for ecological restoration and management of the lakeshore.

The ascomycete Sclerotinia sclerotiorum is a devastating plant pathogen with a very broad host range. In this study, we developed a loop-mediated isothermal amplification (LAMP) assay targeting the Ssos5 sequence for visual detection of S. sclerotiorum. The LAMP reaction was optimal at 63 °C for 45 min. When hydroxynaphthol blue (HNB) was added before amplification, samples with S. sclerotiorum DNA developed a characteristic sky blue colour but those without DNA or with the DNA of nine other plant-pathogenic fungi did not. Results obtained with LAMP and HNB were confirmed when LAMP products were subjected to gel electrophoresis. The detection limit of this LAMP assay for S. sclerotiorum was 0.1 fg μL−1 of genomic DNA per reaction, while that of conventional PCR was 100 fg μL−1. Detection results were identical when 13 samples of rapeseed tissue infected with S. sclerotiorum were subjected to LAMP, conventional PCR, and conventional isolation. Because the LAMP assay reported here is simple, rapid, sensitive, and specific, it should be valuable for the detection of S. sclerotiorum in quarantine efforts and field surveys.

To design an efficient interference management and multiple access scheme for visible light communication (VLC) network, this letter leverages the non-orthogonal multiple access (NOMA), which has received significant attention in the $5^{th}$ generation wireless communication. With the residual interference from the successive interference cancellation in NOMA taken into account, we optimize the power allocation for NOMA VLC network to improve the achievable user rate under user quality of service (QoS) constraint. The performance of the proposed approaches is evaluated by the numerical results., Comment: 5 pages, 4 figures. This article has been submitted to IEEE Communication Letters for publication on July 27, 2016

Resistance of Fusarium graminearum to carbendazim is caused by point mutations in the β2-tubulin gene. The point mutation at codon 167 (TTT → TAT, F167Y) occurs in more than 90% of field resistant isolates in China. To establish a suitable method for rapid detection of the F167Y mutation in F. graminearum, an efficient and simple method with high specificity was developed based on loop-mediated isothermal amplification (LAMP). A set of four primers was designed and optimized to specially distinguish the F167Y mutation genotype. The LAMP reaction was optimal at 63°C for 60 min. When hydroxynaphthol blue dye (HNB) was added prior to amplification, samples with DNA of the F167Y mutation developed a characteristic sky blue color after the reaction but those without DNA or with different DNA did not. Results of HNB staining method were reconfirmed by gel electrophoresis. The developed LAMP had good specificity, stability and repeatability and was suitable for monitoring carbendazim-resistance populations of F. graminearum in agricultural production.

Atmospheric correction can eliminate radiation distortion of remote sensing images caused by atmospheric effects and is the basis of data processing for dynamic monitoring of quantitative indicators. In this paper, 6S and FLAASH based on radiation transfer model are applied to atmospheric correction of SPOT4 image. Judging from the results of correction, atmospheric correction can obtain features reflectivity and expand the scope of the NDVI. But compared with FLAASH model and 6S model, the former can not remove aerosols in SPOT 4 satellite images, the latter can obtain accurate features reflectivity and vegetation index, providing the basis for the next step of information analysis.

Radiometric calibration is the basis of data processing for dynamic monitoring of quantitative indicators using multi-temporal remote sensing images. Its purpose is to eliminate the differences of values between the sensor measured and objectives of the spectral reflectance or spectral radiance. Since the spectrum of the SPOT2/4 satellite images covers a small range, the aerosol model can not be corrected by way of FLAASH, therefore in this paper relative radiometric correction is based on PIF after atmospheric correction achieved. Through sampling and analysis, calibration results are more in line with the actual situation of features radiation reflection and achieve normalized radiation of multi-temporal remote sensing images in dynamic monitoring.

Numerical modeling can be used to obtain geophysical information for earthquake mechanism analysis. During the past decade, differential synthetic aperture radar interferometry (D-InSAR) technology has been applied successfully to research co-seismic field and hypocentral mechanism, which could offer more abundant boundary conditions with higher quality as compared with the conventional methodology of geodetic measurement. This paper reports a model of in-depth co-seismic displacement with this approach. On November 14, 2001, a Ms8.1 earthquake, one of the largest events hitting the Chinese mainland over the past 50 odd years, occurred at the Kunlun Mountains in the northern Tibetan plateau, China. In this model, a co-seismic field is established and a series of hypocentral parameters are extracted on the earthquake applying D-InSAR processing with 2Pass+external DEM mode to 20 pair’s ERS-2 SAR data and combined with field geology investigation as well as GPS observations on permanent stations. D-InSAR co-seismic field shows that the Kunlun Mountain Ms8.1 earthquake produced a 430-kilometer-long surface rupture zone, composed by the western section of Taiyang Lake-Kushuihuan with a length of 30km, the eastern section of Bukadaban Peak-Kunlun Mountain Pass with a length of 350km and a 50km long unbroken step area between the above-mentioned two sections. This rupture zone shows such obvious characteristics as distinct segmentation and a left-lateral slip with little reverse component. The maximum co-seismic sinistral horizontal dislocation is 7.38m, of which 4.30m on the south wall and 3.08m on north wall. The maximum vertical dislocation is 4.0m. By means of Poly3D, a geophysical boundary element method (BEM) developed by Stanford University, and based on the boundary conditions of D-InSAR hypocentral parameter, this paper simulates a 3D distribution of the co-seismic deformation and spatial trend of displacement vector over the shock surface area of 80,000 km2 and its underground areas of 20km in depth. The 3D displacement field shows that the maximum strike displacement Ux occurs at 15km below the surface of the Hoh sai Hu lake east-Yuxi peak segment, with a maximum dislocation of 6.424m, the maximum dip displacement Uy is located 10km below the surface of the Yuxi peak-Kunlun Mountain Pass segment, with a maximum dislocation of 2.067m, and the maximum dip displacement Uz is located 10km below the surface of the Yuxi peak-Kunlun Mountain Pass segment with a maximum dislocation of 3.701m. The simulation displacement vectors indicate that bounded by the almost vertical main rupture plane, the south wall thrusts northward with some subsidence, the north wall moves upwards, the south wall moves from west to east while the north wall does from east to west. As the horizontal offset is dominated by left-lateral vertical displacement, the earthquake is classified as a strike-slip dominant type. Thus it is concluded that the Ms8.1 Kunlun earthquake originated from the Kunlun fault with a set of steep dip, left-lateral and strike-slip reverse faults.

The vertical distribution of dominant genera of bacterivorous nematodes to 150-cm depth in an aquic brown soil was compared after 14 years of four contrasting land uses, i.e., cropland-rice (CR), cropland-maize (CM), abandoned cropland (AC), and woodland (WL). The study was conducted at the Shenyang Experimental Station of Ecology, a Chinese Ecosystem Research Network (CERN) site in Northeast China. Data were analyzed using two-way analysis of variance with land use and depth as independent variables. More than 70% of Chiloplacus, Eucephalobus, and Monhystera spp. were present in the uppermost soil layer (0 to 5 cm) in the CR treatment. In contrast, Chiloplacus and Prismatolaimus spp. were distributed down to 100-cm depth in the AC and CM treatments, respectively. Differences in numbers of Acrobeles, Acrobeloides, Cephalobus, Chiloplacus, Eucephalobus, Monhystera, Plectus, and Prismatolaimus were found among land uses and at various depths. Soil C and N were correlated positively with numbers of Monhystera and Plectus in the CR treatment, Acrobeloides in the CM treatment, and Acrobeles and Acrobeloides in the AC treatment. Soil pH was correlated negatively with Monhystera, Plectus (CR), and Acrobeloides (CM, AC). The relationship of pH with Acrobeles depended on land use: positive in the WL treatment and negative in the AC treatment. Our results suggested that Cephalobus and Prismatolaimus in the CR treatment, and Chiloplacus and Prismatolaimus in the WL treatment, were insensitive to soil properties measured. Differences in vertical distribution should be considered when studying dominant bacterivorous nematode genera among land uses.