High index surface‐exposed and composition‐graded PtCu_(3)@Pt_(3)Cu@Pt nanodendrites for high‐performance oxygen reduction

Alloying and nanostructuring are two strategies used to facilitate the efficient electrocatalysis of the oxygen reduction reaction(ORR)by Pt,where the high index surfaces(HISs)of Pt exhibit superior activity for ORR.Here,we report the fabrication of PtCu3 nanodendrites possessing rich spiny branches exposing n(111)×(110)HISs.The dendrites were formed through an etching‐modulated seeding and growing strategy.Specifically,an oxidative atmosphere was initially applied to form the concaved nanocubes of the Pt‐Cu seeds,which was then switched to an inert atmosphere to promote an explosive growth of dendrites.Separately,the oxidative or inert atmosphere failed to produce this hyperbranched structure.Electrochemical dealloying of the PtCu3 nanodendrites produced Pt3Cu shells with Pt‐rich surfaces where HIS‐exposed dendrite structures were maintained.The resulting PtCu_(3)@Pt_(3)Cu@Pt nanodendrites in 0.1 M HClO4 exhibited excellent mass and area specific activities for ORR,which were 14 and 24 times higher than that of commercial Pt/C,respectively.DFT calculations revealed that Cu alloying and HISs both contributed to the significantly enhanced activity of Pt,and that the oxygen binding energy on the step sites of HISs on the PtCu_(3)@Pt_(3)Cu@Pt nanodendrites approached the optimal value to achieve a near peak‐top ORR activity.

Reliability of Chinese web-based ocular surface disease index questionnaire in dry eye patients:a randomized,crossover study

AIM:To assess the reliability of web-based version of ocular surface disease index in Chinese(C-OSDI)on clinically diagnosed dry eye disease(DE)patients.METHODS:A total of 254 Chinese participants(51%male,129/254;mean age:27.90±9.06 y)with DED completed paper-and web-based versions of C-OSDI questionnaires in a randomized crossover design.Ophthalmology examination and DED diagnosis were performed prior to the participants being invited to join the study.Participants were randomly designated to either group A(paper-based first and webbased second)or group B(web-based first and paper-based second).Final data analysis included participants that had successfully completed both versions of the C-OSDI.Demographic characteristics,test-retest reliability,and agreement of individual items,subscales,and total score were evaluated with intraclass correlation coefficients(ICC),Spearman rank correlation,Wilcoxon test and Rasch analysis.RESULTS:Reliability indexes were adequate,Pearson correlation was greater than 0.8 and ICCs range was 0.827 to 0.982;total C-OSDI score was not statistically different between the two versions.The values of mean-squares fit statistics were very low compared to 1,indicating that the responses to the items by the model had a high degree of predictability.While comparing the favorability 72%(182/254)of the participants preferred web-based assessment.CONCLUSION:Web-based C-OSDI is reliable in assessing DED and correlation with the paper-based version is significant in all subscales and overall total score.Webbased C-OSDI can be administered to assess individuals with DED as participants predominantly favored online assessment.

A modified TOPMODEL introducing the bedrock surface topographic index in Huangbengliu watershed,China

Subsurface stormflow is a dominant runoff mechanism in steep humid mountainous areas.An insite measurement of subsurface stormflow suggests that the bedrock surface plays an important role in the runoff generation and routing process,which was rarely adopted in hydrological modelling studies.To improve the runoff simulation performance,the bedrock surface topographic index is introduced,and a modified TOPMODEL based on the bedrock surface topographic index is developed to simulate the runoff.The modified TOPMODEL is applied to the Huangbengliu(HBL),a steep watershed in Gongga Mountain,and proved to be more appropriate for the HBL watershed,especially for peak simulation.The Nash-Sutcliffe model efficiency(NSE)is improved from 0.24 to 0.58 in the calibration period and from 0.40 to 0.62 in the verification period.The result of this study can advance the understanding of the mechanism of flash floods and contribute flood control and disaster prevention in the HBL watershed and similar areas.

Development of a drill energy utilization index for aiding selection of drill machines in surface mines

Drill machines used in surface mines, particularly in coal, is characterized by a very poor utilization （around 40%） and low availability （around 60%）. The main purpose of this study is to develop a drill selec- tion methodology and simultaneously a performance evaluation technique based on drill cuttings produced and drilling rate achieved. In all 28 blast drilled through were investigated. The drilling was accomplished by 5 different drill machines of Ingersoll-Rand and Revathi working in coal mines of Sonepur Bazari （SECL） and Block-II （BCCL）. The drills are Rotary and Rotary Percussive type using tri- cone rock roller bits. Drill cuttings were collected and sieve analysis was done in the laboratory. Using Rosin Ramler Diagram, coarseness index （CI）, mean chip size （d）, specific-st trace area （SSA） and charac- teristic particle size distribution curves for all the holes drilled were plotted. The predictor equation for drill penetration rate established through multiple regressions was found to have a very good correlation with an index of determination of 0.85. A comparative analysis of particle size distribution curves was used to evaluate the drill efficiency. The suggested approach utilises the area under the curve, after the point of trend reversal and brittleness ratio of the respective bench to arrive at drill energy utilization index （DEUI）, for mapping of drill machine to bench, The developed DEU1 can aid in selecting or mapping a right machine to right bench for achieving higher penetration rate and utilizations.

Changes in Tear-Film Status and Ocular Surface Disease Index Score Following Prolonged Use of Face Mask

Background: Dry eye is characterized by tear film instability, decreased tear volume and a high Ocular Surface Disease Index (OSDI) score. Face masks have been linked to dry eye complaints in recent studies. Purpose: To evaluate the changes in tear-film status and Ocular Surface Disease Index (OSDI) score following prolonged use of face mask. Design: Cross-sectional study. Method: Patients between 18 to 70 years using masks regularly for at least 2 hours/day for at least 5 days/week from different eye-care centres in Dhaka were included. All subjects were divided into 4 groups. Mask use lasted approximately 2 hours/day in Group 1, 4 hours/day in Group 2, 6 hours/day in Group 3 and 8 hours or more/day in Group 4. Evaluation of symptoms, tear- film stability and tear volume was done by Ocular Surface Disease Index (OSDI) scores, Tear-film Break-Up Time (TBUT) and Schirmer-1 test. Average of right & left eye’s Tear-film Break Up time (TBUT) and Schirmer-1 value were noted. Results: Total 100 patients were enrolled (n = 100). The TBUT (p < 0.001) and Schirmer-1 measurement (p = 0.01) were significantly lesser and Ocular Surface Disease Index (OSDI) score were significantly higher in patients using face-masks for longer time (p < 0.001). Conclusion: Patients who wore masks for prolonged time had tear film instability, reduced tear volume and higher Ocular Surface Disease Index (OSDI) score.

RELATIONSHIPS BETWEEN PRECEDING PACIFIC SEA SURFACE TEMPERATURES AND SUBTROPICAL HIGH INDEXES OF MAIN RAINING SEASONS

With correlation analysis and factor analysis methods, the effects of preceding Pacific SSTs on subtropical high indexes of main raining seasons are discussed. The results of correlation analysis show that the effects of SSTs on five subtropical high indexes differ in seasons and regions. The variation of SSTs mostly affects the area and intensity indexes of the subtropical high, followed by the western ridge index, and the effect on the ridge line index is more remarkable than on the north boundary index. The results of factor analysis reveals that the first common factor of SST of each season reflected mainly the inverse relation of SSTs variation between the central and eastern part of equatorial Pacific and the western Pacific, which correlates better with the subtropical high indexes in the main raining seasons than other common factors of SST. The analysis of interdecadal variation indicated that the variation of SSTs was conducive to the emergence of the La Ni?a event before the end of 1970s, such that in the summer the subtropical high is likely to be weaker and smaller and located eastward and northward. After the 1980s, the opposite characteristics prevailed.

Adsorption of Fe on GaAs（100）Surface

The adsorption of one monolayer Fe atoms on an ideal GaAs (100) surface is studied by using the self-consistent tight-binding linear muffin-tin orbital method. The Fe adatom chemisorption on Ga- and As-terminatedsurface are considered separately. A monolayer of S atoms is used to saturate the dangling bonds on one of the supercellsurfaces. Energies of adsorption systems of an Fe atom on different sites are calculated, and the charge transfers areinvestigated. It is found that Fe-As interaction is stronger than Fe-Ga interaction and Fe atoms prefer to be adsorbed onthe As-terminated surface. It is possible for the adsorbed Fe atoms to sit below the As-terminated surface resulting inan Fe-Ga-As mixed layer. The layer projected density states are calculated and compared with that of the clean surface.

Landform Planation Index Extracted from DEMs： A Case Study in Ordos Platform of China

Planation surface, a surface that is almost flat, is a kind of low-relief landforms. Planation surface is the consequence of the denudation and planation processes under a tectonic stable condition. The quantitative expression of the characteristics of planation surface plays a key role in reconstructing and describing the evolutionary process of landforms. In this study, Landform Planation Index(LPI), a new terrain derivative, was proposed to quantify the characteristics of planation surface. The LPIs were calculated based on the summit surfaces formed according to the clustering results of peaks. Ten typical areas in the Ordos Platform located in the central part of the Loess Plateau of China are chosen as the test areas for investigating their planation characteristics with the LPI. The experimental results indicate that the LPI can be effectively used to quantify the characteristics of planation surfaces. In addition, the LPI can be further used to depict the patterns of spatial differentiation in the Ordos Platform. Although the present Ordos Platform area is full of the high-density gullies, its planation characteristics is found to be well preserved. Furthermore, the characteristics of the planation surfaces can also reflect the original morphology of the Ordos Platform before the loess dusts deposition process evolved in this area. The statistical results of the LPI show that there is a gradually increasing tendency along with the increasing of slope gradient of summit surface. It indicates that the characteristics of planation surfaces vary among test areas with different landforms. These findings help to deepen the understanding of planation characteristics of the loess landform and its underlying paleotopography. Results of this study can be also served as an important theoretical reference value for revealing the evolutionary process of loess landform.

Ocular manifestations and quality of life in patients after hematopoietic stem cell transplantation

AIM:To explore the relationship between ocular and systemic conditions and the impact of ocular complications on the quality of life(QOL)in patients after allogeneic hematopoietic stem cell transplantation(ALLO-HSCT).METHODS:Forty-four patients with severe hematopoietic disease were enrolled after ALLO-HSCT at our center from July 2018 to October 2020.They completed two questionnaires:the Ocular Surface Disease Index(OSDI)and the quality-of-life scale for Chinese patients with visual impairment(SQOL-DV1).Ocular conditions and systemic conditions were also assessed.RESULTS:Eye damage was correlated with total bilirubin(P=0.005),and gamma-glutamyl transferase(GGT)(P=0.021).There was no significant correlation between the overall QOL score and OSDI(P=0.8226)or SQOLDV1(P=0.9526)scores.The OSDI and the overall QOL score were not correlated with ocular conditions,including best-corrected visual acuity(BCVA),intraocular pressure,Schirmer tear test II,sodium fluorescein staining,tear film breakup time,and tear meniscus height.SQOLDV1 was correlated with BCVA(P=0.0007),sodium fluorescein staining(P=0.007),and tear film breakup time(P=0.0146).CONCLUSION:In some patients,early ocular symptoms are not evident after ALLO-HSCT,while ocular surface complications can be observed after a comprehensive ophthalmological examination.Especially for those with elevated total bilirubin or GGT,regular ophthalmic follow-up visits are essential to diagnose and treat ocular graft versus host disease(o GVHD),especially for patients with elevated total bilirubin or GGT.

Multiple stacking of InGaAs/GaAs(731) nanostructures

We studied the multilayering effects of InGaAs quantum dots(QDs) on GaAs(731), a surface lying inside of the stereographic triangle. The surfaces after stacking 16 InGaAs layers were characterized with highly non-uniformity of QD spatial distribution. The bunched step regions driven by strain accumulation are decorated by QDs, therefore GaAs(731) becomes a good candidate substrate for the growth of QD clusters. The unique optical properties of the QD clusters are revealed by photoluminescence measurements. By adjusting the coverage of InGaAs, a bamboo-like nanostructured surface was observed and the quantum dots aligned up in clusters to separate the "bamboo" into sections.

The extreme dry/wet events in northern China during recent 100 years

Using monthly precipitation and monthly mean temperature, a surface humid index was proposed. According to the index, the distributed characteristics of extreme dryness has been fully analyzed. The results indicated that there is an obvious increasing trend of extreme dryness in the central part of northern China and northeastern China in the last 10 years, which shows a high frequency period of extreme dryness; while a low frequency period in the regions during the last 100 years. Compared with variation trend of the temperature in these regions, the region of high frequent extreme dryness is consistent with the warming trend in the same region.

Variations of the Surface Wettability Index over the Tibetan Plateau During 1971-2005

Based on 1971-2005 monthly mean maximum/minimum temperature,wind speed,relative humidity,sunshine duration,and precipitation data at 25 stations over the Tibetan Plateau,a study of the largest potential evapotranspiration（LPE） is performed by using the Penman-Monteith model.The surface wettability index（SWI） is calculated and examined,together with its space distribution,interannual and seasonal variations,as well as associated causes.The results suggest that the annual area rainfall exhibits a pronounced increasing trend at 15.0 mm per decade;the annual LPE shows a different-degree decrease at-4.6—-71.6 mm/10 yr.In the southwestern Ngari prefecture and Nyalam county,the annual SWI displays insignificant decline trends compared to increasing trends in other areas of Tibet（0.02-0.09 per decade）.For Tibet,on average,the SWI experiences a noticeable rise at 0.04/10 yr,particularly in 1981-2005.On a seasonal basis,the SWI shows increasing trends,especially in summer.In the 1970s-1980s,the interannual variation is characterized mainly by lower temperature and lower humidity.From the 1990s,air temperature keeps on rising,leading to an appreciable increase in SWI,displayed as a type of warm and humid climate.The salient increases（decrease） of precipitation and relative humidity（mean temperature daily range） are the principal causes of the greatly enhanced SWI in the region.The pronounced decrease in mean wind and sunshine duration also plays an active role.

Eye reflux:an ocular extraesophageal manifestation of gastric reflux

AIM： To suspect laryngopharyngeal reflux（LPR） in patients with ocular surface disease（OSD）. METHODS： The present study evaluated a group of subjects with OSD assessing the Ocular Surface Disease Index（OSDI） and the Reflux Symptom Index（RSI） to detect patients with suspected LPR and define a possible relationship between tests.RESULTS： Two hundred and ninety subjects（175 females, mean age： 60.41±15.68y） were consecutively visited at ophthalmologist offices. One hundred and one（34%） patients had pathological RSI（〉13） and consequently a suspected LPR.CONCLUSION： The current study shows that suspected LPR may be common（34%） in patients with OSD and a suspected LPR may be considered in OSD patients when RSI score is 〉13 and OSDI score is 〉42.

Sea surface salinity-derived indexes for distinguishing two types of El Niño events in the tropical Pacific

In this study,sea surface salinity(SSS)indexes are derived from reanalysis and observational datasets to distinguish the two types of(Central Pacific(CP)and Eastern Pacific(EP))El Niño events in the tropical Pacific.Based on the SSS anomalous spatial and temporal pointwise correlations with sea surface temperature(SST)indexes of two types of El Niño events,the key areas with SSS variations for EP and CP El Niño events are identified.For EP El Niño events,the key areas are located over an arcuate area centered at(0°,130°E)and in the central equatorial Pacific covering(5°S–5°N,175°W–158°W).For CP El Niño events,the key areas are located in the northeastern western Pacific covering(2°N,142°E–170°E)and in the southeastern Pacific covering(20°S–10°S,135°W–95°W).The key areas for EP and CP El Niño events in this study are not located near the dateline in the equatorial Pacific and differ from those obtained from the regression or composite methods.Accordingly,these key areas are used to construct SSS indexes,termed as the CP/EP El Niño SSS index(CSI/ESI),to distinguish EP and CP El Niño events independently.The SSS indexes are verified by different datasets over varying time periods and they can be adequately used to identify the two types of El Niño events and serve as another useful tool for monitoring ENSO.These analyses offer novel insight into how to represent the diversity of El Niño events.

Rail RCF damage quantification and comparison for different damage models

There are several fatigue-based approaches that estimate the evolution of rolling contact fatigue(RCF) on rails over time and built to be used in tandem with multibody simulations of vehicle dynamics. However, most of the models are not directly comparable with each other since they are based on different physical models even though they shall predict the same RCF damage at the end.This article studies different approaches to quantifying RCF and puts forward a measure for the degree of agreement between them. The methodological framework studies various steps in the RCF quantification procedure within the context of one another, identifies the ‘primary quantification step’ in each approach and compares results of the fatigue analyses. In addition to this, two quantities—‘similarity’ and ‘correlation’—have been put forward to give an indication of mutual agreement between models.Four widely used surface-based and sub-surface-based fatigue quantification approaches with varying complexities have been studied. Different operational cases corresponding to a metro vehicle operation in Austria have been considered for this study. Results showed that the best possible quantity to compare is the normalized damage increment per loading cycle coming from different approaches. Amongst the methods studied, approaches that included the load distribution step on the contact patch showed higher similarity and correlation in their results.While the different approaches might qualitatively agree on whether contact cases are ‘damaging’ due to RCF, they might not quantitatively correlate with the trends observed for damage increment values.

Spatio-temporal Variations in Drought with Remote Sensing from the Mongolian Plateau During 1982–2018

The Mongolian Plateau is one of the regions most sensitive to climate change,the more obvious increase of temperature in 21 st century here has been considered as one of the important causes of drought and desertification.It is very important to understand the multi-year variation and occurrence characteristics of drought in the Mongolian Plateau to explore the ecological environment and the response mechanism of surface materials to climate change.This study examines the spatio-temporal variations in drought and its frequency of occurrence in the Mongolian Plateau based on the Advanced Very High Resolution Radiometer(AVHRR)Normalized Difference Vegetation Index(NDVI)(1982–1999)and the Moderate-resolution Imaging Spectroradiometer(MODIS)(2000–2018)datasets;the Temperature Vegetation Dryness Index(TVDI)was used as a drought evaluation index.The results indicate that drought was widespread across the Mongolian Plateau between1982 and 2018,and aridification incremented in the 21 st century.Between 1982 and 2018,an area of 164.38×10^4 km^2/yr suffered from drought,accounting for approximately 55.28%of the total study area.An area of approximately 150.06×10^4 km^2(51.43%)was subject to more than 160 droughts during 259 months of the growing seasons between 1982 and 2018.We observed variable frequencies of drought occurrence depending on land cover/land use types.Drought predominantly occurred in bare land and grassland,both of which accounting for approximately 79.47%of the total study area.These terrains were characterized by low vegetation and scarce precipitation,which led to frequent and extreme drought events.We also noted significant differences between the areal distribution of drought,drought frequency,and degree of drought depending on the seasons.In spring,droughts were widespread,occurred with a high frequency,and were severe;in autumn,they were localized,frequent,and severe;whereas,in summer,droughts were the most widespread and frequent,but less severe.The increase in temperature,decrease in precipitation,continuous depletion of snow cover,and intensification of human activities have resulted in a water deficit.More severe droughts and aridification have affected the distribution and functioning of terrestrial ecosystems,causing changes in the composition and distribution of plants,animals,microorganisms,conversion between carbon sinks and carbon sources,and biodiversity.We conclude that regional drought events have to be accurately monitored,whereas their occurrence mechanisms need further exploration,taking into account nature,climate,society and other influencing factors.

Topographic tear film trend and new parameters for noninvasive break up time test

AIM:To evaluate the quantitative and qualitative results of the noninvasive tear film break-up time(NI-BUT)test and investigate the predictive ability of the new NIBUT parameter in discriminating between normal Ocular Surface Disease Index(OSDI;scores≤12)and abnormal OSDI(scores≥13).METHODS:A total of 341 eyes of 341 volunteers who applied for routine eye outpatient control were included in the prospective study.All participants'noninvasive first tear film break-up time(NIF-BUT),noninvasive average tear film break-up time(NIAvg-BUT)and average value of the first three break-up time(A3F-BUT)were analyzed.A3F-BUT,the new NI-BUT parameter,is calculated by adding the NIF-BUT value to the 2^(nd )break-up time value that has a difference of at most 1 second from the NIF-BUT value and to the 3^(rd) break-up time and then dividing the respective sum by 3.Receiver operating characteristic(ROC)curve and forward logistic regression analyses were performed to determine the parameter that had the best predictive ability between the OSDI groups.RESULTS:The NI-BUT values of 255 eyes of 255 volunteers included in the study were analyzed statistically.The mean NIF-BUT,NIAvg-BUT,and A3F-BUT values were calculated as 5.3±3.0,8±3.1,and 5.8±3.0 seconds,respectively.All three parameters were found to be significantly lower in the abnormal OSDI group(P=0.014,0.034,and 0.011,respectively).The area under the curve(AUC)of the A3F-BUT to predict abnormal OSDI was AUC=0.625(0.529-0.720),P=0.011 and NIF-BUT was AUC=0.599(0.502-0.696),P=0.043.The A3F-BUT parameter and NIF-BUT parameters were found to be significantly efficient in discriminating abnormal OSDI.CONCLUSION:The new parameter for the NI-BUT test has more predictive ability in the discrimination of OSDI groups.

A DEM upscaling method with integrating valley lines based on HASM

A new digital elevation model(DEM)upscaling method based on high accuracy surface modeling(HASM)is proposed by combining the elevation information of DEM and the valley lines extracted from DEM with different flow accumulation thresholds.The proposed method has several advantages over traditional DEM upscaling methods.First,the HASM ensures the smoothness of the upscaled DEM.Secondly,several DEMs with different topographic details can be obtained using the same DEM grid size by incorporating the valley lines with different flow accumulation thresholds.The Jiuyuangou watershed in China’s Loess Plateau was used as a case study.A DEM with a grid size of 5 m obtained from the local surveying and mapping department was used to verify the proposed DEM upscaling method.We established the surface complexity index to describe the complexity of the topographic surface and quantified the differences in the topographic features obtained from different upscaling results.The results show that topography becomes more generalized as grid size and flow accumulation threshold increase.At a large DEM grid size,an increase in the flow accumulation threshold increases the difference in elevation values in different grids,increasing the surface complexity index.This study provides a new DEM upscaling method suitable for quantifying topography.

Distribution and assessment of heavy metals in the surface sediment of Yellow River, China

Large amounts of heavy metals discharged by industrial cities that are located along the middle reach of Yellow River, China have detrimental impacts on both the ecological environment and human health. In this study, fourteen surface sediment samples were taken in the middle reach of the Yellow River. Contents of Zn, Pb, Ni, Cu, Cr, Cd, As were measured, and the pollution status was assessed using three widely used pollution assessment methods, including the single factor index method, Nemerow pollution index method and potential ecological risk index. The concentrations of the studied heavy metals followed the order： Zn 〉 Cr 〉 Cu 〉 Ni 〉 Pb 〉 As 〉 Cd. Nearly 50% of sites had Cu and Cr accumulation. The concentration of Cu at the Yiluo River exceeded the secondary standard value of the Environmental quality standard for soils. Comparison of heavy metal concentrations between this study and other selected rivers indicated that Cu and Cr may be the major pollutants in our case. The single factor index indicated that many samples were at high levels of pollution for Cu and Cd; the Nemerow pollution index indicated that the Yihe River, Luohe River, Yiluo River and Huayuankou were polluted. According to the results of potential ecological risk assessment, Cd in the tributaries of Luo River, Yihe River,and Yiluo River showed high risk toward the ecosystem and human health, Cd in Huanyuankou and Cu in Yiluo River showed a middle level of risk and other samples were at a low level of risk.

Estimating rice paddy areas in China using multi-temporal cloud-free normalized difference vegetation index (NDVI) imagery based on change detection

The spatial pattern of rice paddies is an essential parameter used for studies of greenhouse gas emissions,agricultural resource management,and environmental monitoring.On large spatial scales,previous studies have usually mapped rice paddies using a single vegetation index product based on a traditional classification method,or a combined analysis of various vegetation and water indices derived from the moderate resolution imaging spectroradiometer(MODIS)satellite data.However,different indices increase the computational cost and constrain the satellite data sources,and traditional classification methods(e.g.,maximum likelihood classification)may be time-consuming and difficult to carry out over a large area like China.In this study,we designed an auto-thresholding and single vegetation index(normalized difference vegetation index(NDVI))-based procedure to estimate the spatial distribution of rice paddies in China.The MOD09Q1 product,which was available at MODIS’s highest spatial resolution(250 m),was taken as the input source.An auto-threshold function was also introduced into the change detection process to distinguish rice paddies from other croplands.Our MODIS-derived maps were validated with ground surveys and then compared with China national statistical data of rice paddy areas.The results indicated that the best classification result was achieved for plain regions,and that the accuracy declined for hilly regions,where the complex landscape could lead to an underestimation of the rice paddy area.A comparison between the modeled results and other analyses using 500-m MODIS data suggests that rice paddies may be identified routinely using a single vegetation index with finer resolution on large spatial scales.