Evolving patterns of agricultural production space in China:A network-based approach

The agricultural production space,as where and how much each agricultural product grows,plays a vital role in meeting the increasing and diverse food demands.Previous studies on agricultural production patterns have predominantly centered on individual or specific crop types,using methods such as remote sensing or statistical metrological analysis.In this study,we characterize the agricultural production space(APS)by bipartite network connecting agricultural products and provinces,to reveal the relatedness between diverse agricultural products and the spatiotemporal characteristic of provincial production capabilities in China.The results show that core products are cereal,pork,melon,and pome fruit;meanwhile the milk,grape,and fiber crop show an upward trend in centrality,which is in line with diet structure changes in China over the past decades.The little changes in community components and structures of agricultural products and provinces reveal that agricultural production patterns in China are relatively stable.Additionally,identified provincial communities closely resemble China's agricultural natural zones.Furthermore,the observed growth in production capabilities in North and Northeast China implies their potential focus areas for future agricultural production.Despite the superior production capa-bilities of southern provinces,recent years have witnessed a notable decline,warranting special attentions.The findings provide a comprehensive perspective for understanding the complex relationship of agricultural prod-ucts'relatedness,production capabilities and production patterns,which serve as a reference for the agricultural spatial optimization and agricultural sustainable development.

利用变温扫描隧道显微镜原位测量锐钛矿型TiO_(2)(001)重构表面

金属氧化物表面的催化性能主要取决于其表面原子结构,在不同的样品处理条件和催化反应过程中,表面原子结构通常会发生变化.因此,获得不同处理条件的表面原子形貌对于进一步理解复杂重构表面的催化机理具有重要意义.本文报道了氩离子刻蚀后的锐钛矿TiO_(2)(001)薄膜,在不同温度加热处理下的表面形貌演变,并使用变温扫描隧道显微镜进行了表征.实验结果表明,在不同的加热温度下,样品的表面形貌不同.热处理过程中,O原子从体相向TiO_(2)(001)表面迁移,对形成(1x4)重构过程中Ti^(2+)和Ti^(3+)态的再氧化起了重要作用.TiO_(2)(001)-(1x4)表面的原子级分辨图像显示出不对称的脊链特征,这很好地支持了TiO_(2)(001)-(1x4)重构表面的完全氧化结构模型.

Impact of Drought on Agriculture in the Indo-Gangetic Plain,India

In this study, we investigate the spatiotemporal characteristics of drought in India and its impact on agriculture during the summer season （April-September）. In the analysis, we use Standardized Precipitation Evapotranspiration Index （SPEI） datasets between 1982 and 2012 at the six-monthly timescale. Based on the criterion SPEI 〈 -1, we obtain a map of the number of occurrences of drought and find that the humid subtropical Upper Middle Gangetic Plain （UMGP） region is highly drought-prone, with an occurrence frequency of 40%-45%. This UMGP region contributes at least 18%-20% of India＇s annual cereal production. Not only the probability of drought, but the UMGP region has become increasingly drought-prone in recent decades. Moreover, cereal production in the UMGP region has experienced a gradual declining trend from 2000 onwards, which is consistent with the increase in drought-affected areas from 20%-25% to 50%-60%, before and after 2000, respectively. A higher correlation coefficient （-0.69） between the cereal production changes and drought-affected areas confirms that at least 50% of the agricultural （cereal） losses are associated with drought. While analyzing the individual impact of precipitation and surface temperature on SPEI at 6 month timescale [SPEI （6）] we find that, in the UMGP region, surface temperature plays the primary role in the lowering of the SPEI. The linkage is further confirmed by correlation analysis between SPEI （6） and surface temperature, which exhibits strong negative values in the UMGP region. Higher temperatures may have caused more evaporation and drying, which therefore increased the area affected by drought in recent decades.

Malignant solitary pulmonary nodules: size and attenuation measured on a PACS and CT workstation

Objective: The aim of our study was to determine the efficiency and effectiveness of picture archiving and communication system(PACS) workstation in detecting the sizes and attenuation of malignant solitary pulmonary nodules(SPNs). Methods: Forty patients with malignant SPNs(diameter ≤ 3 cm) underwent multidetector-row computed tomography(CT) of the chest in a single-breath-hold technique. The raw data were acquired with a collimation of 0.625 mm. The diameters and attenuation of malignant SPNs were measured on PACS and CT workstation respectively. The diameter was defined as the average value of the anteroposterior, lateral and superoinferior diameters on CT scans obtained with a mediastinal window setting. The superoinferior diameters were measured on MPR image. The diameters and attenuation of malignant SPNs and spending time in measuring were recorded. Results: The diameters of malignant SPNs measured on a PACS and CT workstation were 2.09 cm ± 0.87 cm, 2.07 cm ± 0.79 cm, respectively. There was not statistically significant difference in the diameters of malignant SPNs between that measured on a PACS workstation and that on a CT workstation(t = 1.580, P = 0.210 > 0.05). The attenuation of malignant SPNs measured on a PACS and CT workstation were 40.15 HU ± 7.53 HU, 39.99 HU ± 8.13 HU, respectively. There was not statistically significant difference in the attenuation of malignant SPNs between that measured on a PACS workstation and that on a CT workstation(t = 1.008, P = 0.298 > 0.05). The spending time in measuring on a PACS and CT workstation were 55 s ± 4.03 s, 56 s ± 3.95 s, respectively. No statistically significant difference was found in spending time in measuring between that on a PACS workstation and that on a CT workstation(t = 0.958, P = 0.315 > 0.05). Conclusion: The efficiency and effectiveness of PACS workstation is as same as those of CT workstation in detecting the sizes and attenuation of malignant SPNs. It is suggested that the size and attenuation of malignant SPNs are measured on a PACS and CT workstation.

Progression of hepatic hyperperfusion disorders revealed during follow-up CT scan of digestive system neoplasm

Objective： The aim of this study was to investigate progression of hepatic hyperperfusion disorders revealed during follow-up contrast material-enhanced multi-slice spiral computed tomography （MSCT） scan of digestive system neoplasm. Methods： Three-phase contrast material-enhanced MSCT were performed during the follow-up in patients with digestive system malignant tumor confirmed histologically. The progression of hepatic hyperperfusion disorders revealed on contrast material-enhanced CT image were investigated at the 2 years follow-up with approximately 6 months interval. Results： The hepatic hyperperfusion disorders were showed in 39 patients on follow-up contrast material-enhanced MSCT scans. Among the 39 patients, initial hyperperfusion disorders were revealed in 6 （15.38%）, 26 （66.67%）, and 7 （17.95%） patients in 6, 12, and 18 months during follow-up respectively. The initial hyperperfusion disorders revealed in 12 months were more frequent than those revealed in 6 months （X2 = 14.82, P 〈 0.05） and 18 months （X2 = 15.02, P 〈 0.05）. Among the 39 patients, the hyperperfusion disorders progressed into liver metastasis based on typical CT findings in 37 （94.87%） patients, and were not obvious changes in 2 （5.13%） patients. Among the 37 patients, the hyperperfusion disorders progressed into metastasis in 10 （25.64%） patients in 6 months after the hyperperfusion disorders were revealed, and in 27（69.23%） patients in 12 months. The hyperperfusion disorders developing into metastasis were more in 12 months than those in 6 months （X2= 14.98, P 〈 0.05）. Conclusion： Most hepatic hyperperfusion disorders revealed at the follow-up of digestive system neoplasm may be early manifestations of liver metastasis. The careful follow-up of hepatic hyperperfusion disorders is necessary.

Efficacy of DR, CT and MRI in bone tumors

Objective: The aim of the study was to investigate the efficacy of digital radiography(DR), computed tomography(CT) and magnetic resonance imaging(MRI) in bone tumors. Methods: Fifty-five patients with histologically confirmed bone tumors underwent imaging examinations. Fifty-five patients were performed DR, 21 CT and 20 MRI. Results: DR of 51 patients clearly revealed bone changes. DR of 40 patients well showed marginal. Twenty tumors appeared periosteal reaction on DR and 19 calcification on DR. CT scan of 21 patients clearly depicted bone changes, marginal and calcification and CT scan of 8 revealed periosteal reaction. MRI scan of 20 patients all showed marginal and soft-tissue mass and bone marrow edema was prominent in 8 patients. Conclusion: DR is the first imaging approach for born tumors. CT well reveal the extent and minute structure of the bone tumors, the extent, soft-tissue mass and bone marrow edema are more dramatically demonstrated on MRI imaging. DR integrates with CT and MRI, is helpful in diagnosis of bone tumors.

Peripheral bronchogenic carcinoma: Enhancement pattern evaluation on PACS and CT workstations

Objective: The aim of the study was to determine the efficiency and effectiveness of picture archiving and communication system(PACS) workstation in detecting enhancement pattern of peripheral bronchogenic carcinoma. Methods: The 62 patients with peripheral bronchogenic carcinoma underwent two-phase contrast material-enhanced multislices computed tomography(MSCT) of the chest in a single-breath-hold technique. Two spiral CT scans were obtained at 25 s and 90 s respectively after nonionic contrast material was administrated via the antecubital vein at a rate of 4 m L/s by using an autoinjector. Precontrast and postcontrast attenuation on every scan were measured on PACS and CT workstations respectively and peak height was calculated. Enhancement pattern was evaluated on the image obtained at 90 s after injection of contrast medium on PACS and CT workstations respectively. Results: No statistically significant difference in precontrast attenuation, postcontrast attenuation at 25 s and 90 s was found between these measured on a PACS workstation [(40.21 ± 7.03) HU;(55.53 ± 11.09) HU;(75.95 ± 13.45) HU] and those [(39.01 ± 8.95) HU;(56.01 ± 10.91) HU;(76.03 ± 11.95) HU] on a CT workstation(t = 1.140, P = 0.256 > 0.05; t = 1.580, P = 0.149 > 0.05; t = 1.505, P = 0.150﹥0.05). The peak height that calculated on a PACS workstation was 35.74 HU(20 HU). There was not statistically significant difference in peak height between that calculated on a PACS workstation and that on a CT workstation [(37.02 ± 12.05) HU; t = 2.001, P = 0.099 > 0.05]. The tumors showed same enhancement pattern on PACS workstation and CT workstation. Of the 62 cases, 38 showed homogeneous enhancement, 17 showed heterogeneous enhancement, five showed peripheral enhancement, two showed central enhancement, at 90 s. The enhancement pattern revealed on PACS workstation was consistent with feature of peripheral bronchogenic carcinoma. Conclusion: The efficiency and effectiveness of PACS workstation is as same as those of CT workstation in detecting enhancement pattern of peripheral bronchogenic carcinoma.

Pedotransfer functions for predicting bulk density of coastal soils in East China

Soil bulk density(BD) is an important physical property and an essential factor for weight-to-volume conversion. However, BD is often missing from soil databases because its direct measurement is labor-intensive, time-consuming, and sometimes impractical, particularly on a large scale. Therefore, pedotransfer functions(PTFs) have been developed over several decades to predict BD. Here, six previously revised PTFs(including five basic functions and stepwise multiple linear regression(SMLR)) and two new PTFs, partial least squares regression(PLSR) and support vector machine regression(SVMR), were used to develop BD-predicting PTFs for coastal soils in East China. Predictor variables included soil organic carbon(SOC) and particle size distribution(PSD). To compare the robustness and reliability of the PTFs used, the calibration and prediction processes were performed 1 000 times using the calibration and validation sets divided by a random sampling algorithm. The results showed that SOC was the most important predictor, and the revised PTFs performed reasonably although only SOC was included. The PSD data were useful for a better prediction of BD, and sand and clay fractions were the second and third most important properties for predicting BD. Compared to the other PTFs, the PLSR was shown to be slightly better for the study area(the average adjusted coefficient of determination for prediction was 0.581). These results suggest that PLSR with SOC and PSD data can be used to fill in the missing BD data in coastal soil databases and provide important information to estimate coastal carbon storage, which will further improve our understanding of sea-land interactions under the conditions of ongoing global warming.

Integrating global socio-economic influences into a regional land use change model for China

With rapid economic development and urba- nization, land use in China has experienced huge changes in recent years; and this will probably continue in the future. Land use problems in China are urgent and need further study. Rapid land-use change and economic development make China an ideal region for integrated land use change studies, particularly the examination of multiple factors and global-regional interactions in the context of global economic integration. This paper presents an integrated modeling approach to examine the impact of global socio-economic processes on land use changes at a regional scale. We develop an integrated model system by coupling a simple global socio-economic model （GLOBFOOD） and regional spatial allocation model （CLUE）. The model system is illustrated with an application to land use in China. For a given climate change, population growth, and various socio-economic situations, a global socio-economic model simulates the impact of global market and economy on land use, and quantifies changes of different land use types. The land use spatial distribution model decides the type of land use most appropriate in each spatial grid by employing a weighted suitability index, derived from expert knowledge abot^t the ecosystem state and site conditions. A series of model simulations will be conducted and analyzed to demonstrate the ability of the integrated model to link global socio- economic factors with regional land use changes in China. The results allow an exploration of the future dynamics of land use and landscapes in China.