Detection of nitrogen-overfertilized rice plants with leaf positional difference in hyperspectral vegetation index

The main objective of this work was to compare the applicability of the single leaf (the uppermost leaf L1 and the third uppermost leaf L3) modified simple ratio (mSR₇₀₅ index) and the leaf positional difference in the vegetation index between L1 and L3 (mSR_705L1-mSR_705L3) in detecting nitrogen (N)-overfertilized rice plants. A field experiment consisting of three rice genotypes and five N fertilization levels (0, 75, 180, 285, and 390 kg N/ha) was conducted at Xiaoshan, Hangzhou, Zhejiang Province, China in 2008. The hyperspectral reflectance (350–2500 nm) and the chlorophyll concentration (ChlC) of L1 and L3 were measured at different stages. The mSR_705L1 and mSR_705L3 indices appeared not to be highly sensitive to the N rates, especially when the N rate was high (above 180 kg N/ha). The mean mSR_705L1-mSR_705L3 across the genotypes increased significantly (P<0.05) or considerably from 180 to 285 kg N/ha treatment and from 285 to 390 kg N/ha treatment at all the stages. Also, use of the difference (mSR_705L1-mSR_705L3) greatly reduced the influence of the stages and genotypes in assessing the N status with reflectance data. The results of this study show that the N-overfertilized rice plants can be effectively detected with the leaf positional difference in the mSR₇₀₅ index.     

In situ hyperspectral data analysis for pigment content estimation of rice leaves

INTRODUCTIONPigmentsarecloselyrelatedtothephysiolog icalfunctionofleaves.Chlorophyllsabsorblightenergyandtransferitintothephotosyntheticpro cess.Carotenoids (yellowpigments)canalsocontributeenergytothephotosyntheticsystem .Becauseoftheimportanceofpigments…     

In situ hyperspectral data analysis for pigment content estimation of rice leaves

Analyses of the correlation between hyperspectral reflectance and pigment content including chlorophyll-a, chlorophyll-b and carotenoid of leaves in different sites of rice were reported in this paper. The hyperspectral reflectance of late rice during the whole growing season was measured using a Spectroradiometer with spectral range of 350–1050 nm and resolution of 3 nm. The chlorophyll-a, chlorophyll-b and carotenoid contents in rice leaves in rice fields to which different levels of nitrogen were applied were measured. The chlorophyll-a content of upper leaves was well correlated with the spectral variables. However, the correlation between both chlorophyll-b and caroteniod and the spectral variables was far from that of chlorophyll-a. The potential of hyperspectral reflectance measurement for estimating chlorophyll-a of upper leaves was evaluated using univariate correlation and multivariate regression analysis methods with different types of predictors. This study showed that the most suitable estimated model of chlorophyll-a of upper leaves was obtained by using some hyperspectral variables such asSD _r,SD _b and their integration. Project (No. 40171065) supported by the National Natural Science Foundation of China.     

In situ hyperspectral data analysis for pigment content estimation of rice leaves

Analyses of the correlation between hyperspectral reflectance and pigment content including chlorophyll-a, chlorophyll-b and carotenoid of leaves in different sites of rice were reported in this paper. The hyperspectral reflectance of late rice during the whole growing season was measured using a Spectroradiometer with spectral range of 350-1050 nm and resolution of 3 nm. The chlorophyll-a, chlorophyll-b and carotenoid contents in rice leaves in rice fields to which different levels of nitrogen were applied were measured. The chlorophyll-a content of upper leaves was well correlated with the spectral variables. However, the correlation between both chlorophyll-b and caroteniod and the spectral variables was far from that of chlorophyll-a. The potential of hyperspectral reflectance measurement for estimating chlorophyll-a of upper leaves was evaluated using univariate correlation and multivariate regression analysis methods with different types of predictors. This study showed that the most suitable estimated model of chlorophyll-a of upper leaves was obtained by using some hyperspectral variables such as SDr, SDb and their integration.     

Discrimination of rice panicles by hyperspectral reflectance data based on principal component analysis and support vector classification

Detection of crop health conditions plays an important role in making control strategies of crop disease and insect damage and gaining high-quality production at late growth stages. In this study, hyperspectral reflectance of rice panicles was measured at the visible and near-infrared regions. The panicles were divided into three groups according to health conditions: healthy panicles, empty panicles caused by Nilaparvata lugens Stul, and panicles infected with Ustilaginoidea virens. Low order derivative sp...     

Multi-year monitoring of paddy rice planting area in Northeast China using MODIS time series data

The objective of this study was to investigate the tempo-spatial distribution of paddy rice in Northeast China using moderate resolution imaging spectroradiometer(MODIS) data.We developed an algorithm for detection and estimation of the transplanting and flooding periods of paddy rice with a combination of enhanced vegetation index(EVI) and land surface water index with a central wavelength at 2130 nm(LSWI2130).In two intensive sites in Northeast China,fine resolution satellite imagery was used to validate the performance of the algorithm at pixel and 3×3 pixel window levels,respectively.The commission and omission errors in both of the intensive sites were approximately less than 20%.Based on the algorithm,annual distribution of paddy rice in Northeast China from 2001 to 2009 was mapped and analyzed.The results demonstrated that the MODIS-derived area was highly correlated with published agricultural statistical data with a coefficient of determination(R2) value of 0.847.It also revealed a sharp decline in 2003,especially in the Sanjiang Plain located in the northeast of Heilongjiang Province,due to the oversupply and price decline of rice in 2002.These results suggest that the approaches are available for accurate and reliable monitoring of rice cultivated areas and variation on a large scale.     

Mapping paddy rice with multi-date moderate-resolution imaging spectroradiometer （MODIS） data in China

The objective of this study was to obtain spatial distribution maps of paddy rice fields using multi-date moderateresolution imaging spectroradiometer （MODIS） data in China. Paddy rice fields were extracted by identifying the unique characteristic of high soil moisture in the flooding and transplanting period with improved algorithms based on rice growth calendar regionalization. The characteristic could be reflected by the enhanced vegetation index （EVI） and the land surface water index （LSWI） derived from MODIS sensor data. Algorithms for single, early, and late rice identification were obtained from selected typical test sites. The algorithms could not only separate early rice and late rice planted in the same fields, but also reduce the uncertainties. The areal accuracy of the MODIS-derived results was validated by comparison with agricultural statistics, and the spatial matching was examined by ETM＋ （enhanced thematic mapper plus） images in a test region. Major factors that might cause errors, such as the coarse spatial resolution and noises in the MODIS data, were discussed. Although not suitable for monitoring the inter-annual variations due to some inevitable factors, the MODIS-derived results were useful for obtaining spatial distribution maps of paddy rice on a large scale, and they might provide reference for further studies.     

Growth and yield of rice as affected by transplanting dates and seedlings per hill under high temperature of Dera Ismail Khan, Pakistan

Studies were initiated for two consecutive years to find out the effect of time of transplanting and seedlings hill^-l on the productivity of rice in Dera Ismail Khan district of North West Frontier Province （NWFP）, Pakistan. The experiment was laid out in a randomized complete block design with split plot arrangements. Main plots consisted of four transplanting dates viz. 20th and 27th of June and 4th and 1 lth of July while sub-plots contained 1, 2, 3 or 4 seedlings hill^-1. Among transplanting dates, June 20th planted crop gave highest paddy yield and net return with I seedling hill^-1. It explains that the use of more seedlings hill^-1 not only adds to cost but is also a mere wastage of natural resources. Based on research findings, we conclude that the use of I seedling hill^-1 is most appropriate for timely sowing otherwise 4 seedlings hill^-1 should be used to compensate for the yield gap in late transplanted rice.     

Characterizing and estimating rice brown spot disease severity using stepwise regression,principal component regression and partial least-square regression

Detecting plant health conditions plays a key role in farm pest management and crop protection. In this study, measurement of hyperspectral leaf reflectance in rice crop (Oryzasativa L.) was conducted on groups of healthy and infected leaves by the fungus Bipolaris oryzae (Helminthosporium oryzae Breda. de Hann) through the wavelength range from 350 to 2 500 nm. The percentage of leaf surface lesions was estimated and defined as the disease severity. Statistical methods like multiple stepwise regression, principal component analysis and partial least-square regression were utilized to calculate and estimate the disease severity of rice brown spot at the leaf level. Our results revealed that multiple stepwise linear regressions could efficiently estimate disease severity with three wavebands in seven steps. The root mean square errors (RMSEs) for training (n=210) and testing (n=53) dataset were 6.5% and 5.8%, respectively. Principal component analysis showed that the first principal component could explain approximately 80% of the variance of the original hyperspectral reflectance. The regression model with the first two principal components predicted a disease severity with RMSEs of 16.3% and 13.9% for the training and testing dataset, respec-tively. Partial least-square regression with seven extracted factors could most effectively predict disease severity compared with other statistical methods with RMSEs of 4.1% and 2.0% for the training and testing dataset, respectively. Our research demon-strates that it is feasible to estimate the disease severity of rice brown spot using hyperspectral reflectance data at the leaf level.     

Comparative mapping of QTLs for Al tolerance in rice and identification of positional Al-induced genes

INTRODUCTION Aluminum (Al) toxicity is one of the mostimportant yield-limiting factors for crop grown onacid upland and lowland acid sulphate soils (IRRI,1978). Al toxicity results in a reduced and damagedroot system, which in turn causes the affectedplants to be susceptible to drought stress and min-eral nutrient deficiencies (Foy, 1988). The physio-logical and biochemical mechanisms of the toxiceffect of Al on root elongation had been extensivelyinvestigated (Matsumoto, 2000). T…     

Comparative mapping of QTLs for Al tolerance in rice and identification of positional Al-induced genes

Aluminum (Al) toxicity is the major factor limiting crop productivity in acid soils. In this study, a recombinant inbreed line (RIL) population derived from a cross between an A1 sensitive lowland indica rice variety IR1552 and an Al tolerant upland japonica rice variety Azucena, was used for mapping quantitative trait loci (QTLs) for A1 tolerance. Three QTLs for relative root length (RRL) were detected on chromosome 1, 9, 12, respectively, and I QTL for root length under Al stress is identical on chromosome I after one week and two weeks stress. Comparison of QTLs on chromosome 1 from different studies indicated an identical interval between C86 and RZ801 with gene(s) for Al tolerance. This interval provides an important start point for isolating genes responsible for A1 tolerance and understanding the genetic nature of Al tolerance in rice. Four Al induced ESTs located in this interval were screened by reverse Northern analysis and confirmed by Northern analysis. They would be candidate genes for the QTL.     

Charlson合并症指数对2型糖尿病肾病死亡率预测作用的研究(英文)简

Our intent is to examine the predictive role of Charlson comorbidity index （CCI） on mortality of patients with type 2 diabetic nephropathy （DN）. Based on the CCI score, the severity of comorbidity was categorized into three grades： mild, with CCI scores of 1-2; moderate, with CCI scores of 3-4; and severe, with CCI scores 〉5. Factors influencing mortality and differences between groups stratified by CCI were determined by logistical regression analysis and one-way analysis of variance （ANOVA）. The impact of CCI on mortality was assessed by the Kaplan- Meier analysis. A total of 533 patients with type 2 DN were enrolled in this study, all of them had comorbidity （CCI score 〉1）, and 44.7% （238/533） died. The mortality increased with CCI scores： 21.0% （50/238） patients with CCI scores of 1-2, 56.7% （135/238） patients with CCI scores of 3-4, and 22.3% （53/238） patients with CCI scores 〉5. Logistical regression analysis showed that CCI scores, hemoglobin, and serum albumin were the potential predictors of mortality （P〈0.05）. One-way ANOVA analysis showed that DN patients with higher CCI scores had lower levels of hemoglobulin, higher levels of serum creatinine, and higher mortality rates than those with lower CCI scores. The Kaplan-Meier curves showed that survival time decreased when the CCI scores and mortality rates went up. In con- clusion, CCI provides a simple, readily applicable, and valid method for classifying comorbidities and predicting the mortality of type 2 DN. An increased awareness of the potential comorbidities in type 2 DN patients may provide insights into this complicated disease and improve the outcomes by identifying and treating patients earlier and more effectively.     

Quantitative trait loci analysis for rice seed vigor during the germination stage

Seed vigor is an important characteristic of seed quality, and rice cultivars with strong seed vigor are desirable in direct-sowing rice production for optimum stand establishment. In the present study, the quantitative trait loci (QTLs) of three traits for rice seed vigor during the germination stage, including germination rate, final germination percentage, and germination index, were investigated using one recombinant inbred line (RIL) population derived from a cross between japonica Daguandao and indica IR28, and using the multiple interval mapping (MIM) approach. The results show that indica rice presented stronger seed vigor during the germination stage than japonica rice. A total of ten QTLs, and at least five novel alleles, were detected to control rice seed vigor, and the amount of variation (R ²) explained by an individual QTL ranged from 7.5% to 68.5%, with three major QTLs with R ²>20%. Most of the QTLs detected here are likely to coincide with QTLs for seed weight, seed size, or seed dormancy, suggesting that the rice seed vigor might be correlated with seed weight, seed size, and seed dormancy. At least five QTLs are novel alleles with no previous reports of seed vigor genes in rice, and those major or minor QTLs could be used to significantly improve the seed vigor by marker-assisted selection (MAS) in rice.     

两种自动识别技术在图书馆应用上的对比研究

本文通过对条码技术和射频识别技术在图书馆应用上的对比研究以及对其引进、使用的情况分析，阐述了作者在图书馆引进射频识别技术问题上与目前学术主流观点不一致的意见，并指出图书馆在认识射频技术优势问题上存在明显误区。     

A new class of negative refractive index transmission line

We propose a new class of negative refractive index transmission line in which ideal operational amplifiers are applied to form the periodically loaded negative-impedance-converted inductors and capacitors. The phase response of the new trans-mission line is opposite to that of a positive refractive index conventional transmission line. Unlike the existing negative refractive index transmission line,the new negative refractive index transmission line is non-dispersive and thus can lead to many novel applications such as designing new broadband devices.     

Simultaneous removal of cadmium and sulfamethoxazole from aqueous solution by rice straw biochar

The simultaneous sorption behavior and characteristics of cadmium (Cd) and sulfamethoxazole (SMX) on rice straw biochar were investigated. Isotherms of Cd and SMX were well modeled by the Langmuir equation (R2 >0.95). The calculated maximum adsorption parameter (Q) of Cd was similar in single and binary systems (34129.69 and 35919.54 mg/kg, respectively). However, the Q of SMX in a binary system (9182.74 mg/kg) was much higher than that in a single system (1827.82 mg/kg). The presence of Cd significantly promoted the sorption of SMX on rice straw biochar. When the pH ranged from 3 to 7.5, the sorption of Cd had the characteristics of a parabola pattern with maximum adsorption at pH 5, while the adsorption quantity of SMX decreased with increasing pH, with maximum adsorption at pH 3. The amount of SMX adsorbed on biochar was positively correlated with the surface area of the biochar, and the maximum adsorption occurred with d 250 biochar (biochar with a diameter of 150-250 μm). Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) showed that the removal of Cd and SMX by rice straw biochar may be attributed to precipitation and the formation of surface complexes between Cd or SMX and carboxyl or hydroxyl groups. The results of this study indicate that rice straw biochar has the potential for simultaneous removal of Cd and SMX from co-contaminated water.     

Application of formant instantaneous characteristics to speech recognition and speaker identification

This paper proposes a new phase feature derived from the formant instantaneous characteristics for speech recognition (SR) and speaker identification (SI) systems. Using Hilbert transform (HT), the formant characteristics can be represented by instantaneous frequency (IF) and instantaneous bandwidth, namely formant instantaneous characteristics (FIC). In order to explore the importance of FIC both in SR and SI, this paper proposes different features from FIC used for SR and SI systems. When combing these new features with conventional parameters, higher identification rate can be achieved than that of using Mel-frequency cepstral coefficients (MFCC) parameters only. The experiment results show that the new features are effective characteristic parameters and can be treated as the compensation of conventional parameters for SR and SI.     

PRO-ESPRIT 算法在声表面波标签识别中的应用

The surface acoustic wave (SAW) identification (ID)-tags have great potential for application in radio frequency identification (RFID) due to their characteristics of wireless sensing and passive operation. In the measurements based on the frequency domain sampling (FDS), to expand the range of detection and allow the system work in harsh environments, it is necessary to enhance the identification capability at low SNR. In addition, to identify the tags in real time, it is important to reduce identification time. Therefore, estimation of signal parameters based on the Procrustes rotations via the rotational invariance technique (PRO-ESPRIT) is adopted. Experimental results show that good identification capability is achieved with a relatively faster measurement speed.     

Science Letters: Lattice type transmission line of negative refractive index

In this letter, we introduce a novel passive transmission line of negative refractive index (i.e., left-handedness) based on identical symmetrical lattice type structures [thus called "lattice type transmission line" (LT-TL)]. The dispersion characteristic and the transmission response of the proposed LT-TL are analyzed. While all the other left-handed passive transmission lines are of high pass, the present passive left-handed transmission line is of low pass. Compared with a conventional transmission line, the LT-TL has a phase shift of 180° in the entire wide pass-band.     

Science Letters: Lattice type transmission line of negative refractive index

In this letter, we introduce a novel passive transmission line of negative refractive index （i.e., left-handedness） based on identical symmetrical lattice type structures [thus called ＂lattice type transmission line＂ （LT-TL）]. The dispersion characteristic and the transmission response of the proposed LT-TL are analyzed. While all the other left-handed passive transmission lines are of high pass, the present passive left-handed transmission line is of low pass. Compared with a conventional transmission line, the LT-TL has a phase shift of 180° in the entire wide pass-band.