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China Agricultural University is a university in Beijing, People's Republic of China specializing in agriculture, biology, engineering, veterinary medicine, economics, management, humanities and social science. It was formed in 1905 through the merger of the Beijing Agricultural University and the Beijing Agricultural Engineering University. At present there are around 12,500 undergraduate and 7,000 graduate students studying in the university. The new gymnasium, hosted the wrestling events during the 2008 Summer Olympics. Wikipedia.

Li L.,China Agricultural University
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2012

Based on the research of agriculture and food production in China, the urgent problems of the preliminary processing of agricultural products were pointed out: such as distribution, cleaning, drying, preservation, storage, transportation of agricultural products and marketing information etc. The preliminary processing of agricultural products is a system engineering. Learning experiences from the other countries, specific recommendations were given: it needed long-term stability government-funded. Through the support of government, mechanical equipment, storage facilities were completed by research institutions and enterprises. Modernization of the agricultural business as a carrier, efforts should be made to train farmers operators, organize agricultural cooperatives, create agricultural products processing industry clusters, focusing on the origin conditions and products advantage, establish local standards, facing market needs, based on independent business and innovation, create local brand. It points direction for the preliminary processing of agricultural products in China.

Huang C.,China Agricultural University | Huang C.,China National Institute of Biological Sciences | Zhang Z.,China National Institute of Biological Sciences | Xu M.,China National Institute of Biological Sciences | And 5 more authors.
PLoS Genetics | Year: 2013

Previously, we reported that little canonical (H3.1-H4)2 tetramers split to form "hybrid" tetramers consisted of old and new H3.1-H4 dimers, but approximately 10% of (H3.3-H4)2 tetramers split during each cell cycle. In this report, we mapped the H3.3 nucleosome occupancy, the H3.3 nucleosome turnover rate and H3.3 nucleosome splitting events at the genome-wide level. Interestingly, H3.3 nucleosome turnover rate at the transcription starting sites (TSS) of genes with different expression levels display a bimodal distribution rather than a linear correlation towards the transcriptional activity, suggesting genes are either active with high H3.3 nucleosome turnover or inactive with low H3.3 nucleosome turnover. H3.3 nucleosome splitting events are enriched at active genes, which are in fact better markers for active transcription than H3.3 nucleosome occupancy itself. Although both H3.3 nucleosome turnover and splitting events are enriched at active genes, these events only display a moderate positive correlation, suggesting H3.3 nucleosome splitting events are not the mere consequence of H3.3 nucleosome turnover. Surprisingly, H3.3 nucleosomes with high splitting index are remarkably enriched at enhancers in a cell-type specific manner. We propose that the H3.3 nucleosomes at enhancers may be split by an active mechanism to regulate cell-type specific transcription. © 2013 Huang et al.

Mei S.-L.,China Agricultural University
The Scientific World Journal | Year: 2014

Combining the variational iteration method (VIM) with the sparse grid theory, a dynamic sparse grid approach for nonlinear PDEs is proposed in this paper. In this method, a multilevel interpolation operator is constructed based on the sparse grids theory firstly. The operator is based on the linear combination of the basic functions and independent of them. Second, by means of the precise integration method (PIM), the VIM is developed to solve the nonlinear system of ODEs which is obtained from the discretization of the PDEs. In addition, a dynamic choice scheme on both of the inner and external grid points is proposed. It is different from the traditional interval wavelet collocation method in which the choice of both of the inner and external grid points is dynamic. The numerical experiments show that our method is better than the traditional wavelet collocation method, especially in solving the PDEs with the Nuemann boundary conditions. © 2014 Shu-Li Mei.

Yang Y.-X.,Nanjing Agricultural University | Dai Z.-L.,China Agricultural University | Zhu W.-Y.,Nanjing Agricultural University
Amino Acids | Year: 2014

Bacteria in pig intestine can actively metabolize amino acids (AA). However, little research has focused on the variation in AA metabolism by bacteria from different niches. This study compared the metabolism of AA by microorganisms derived from the lumen and epithelial wall of the pig small intestine, aiming to test the hypothesis that the metabolic profile of AA by gut microbes was niche specific. Samples from the digesta, gut wall washes and gut wall of the jejunum and ileum were used as inocula. Anaerobic media containing single AA were used and cultured for 24 h. The 24-h culture served as inocula for the subsequent 30 times of subcultures. Results showed that for the luminal bacteria, all AA concentrations except phenylalanine in the ileum decreased during the 24-h in vitro incubation with a increase of ammonia concentration, while 4 AA (glutamate, glutamine, arginine and lysine) in the jejunum decreased, with the disappearance rate at 60-95 %. For tightly attached bacteria, all AA concentrations were generally increased during the first 12 h and then decreased coupled with first a decrease and then an increase of ammonia concentration, suggesting a synthesis first and then a catabolism pattern. Among them, glutamate in both segments, histidine in the jejunum and lysine in the ileum increased significantly during the first 12 h and then decreased at 24 h. The concentrations of glutamine and arginine did not change during the first 12 h, but significantly decreased at 24 h. Jejunal lysine and ileal threonine were increased for the first 6 or 12 h. For the loosely attached bacteria, there was no clear pattern for the entire AA metabolism. However, glutamate, methionine and lysine in the jejunum decreased after 24 h of cultivation, while glutamine and threonine in the jejunum and glutamine and lysine in the ileum increased in the first 12 h. During subculture, AA metabolism, either utilization or synthesis, was generally decreased with disappearance rate around 20-40 % for most of AA and negligible for branch chained AA (BCAA). However, the disappearance rate of lysine in each group was around 90 % throughout the subculture, suggesting a high utilization of lysine by bacteria from all three compartments. Analysis of the microbial community during the 24-h in vitro cultivation revealed that bacteria composition in most AA cultures varied between different niches (lumen and wall-adherent fractions) in the jejunum, while being relatively similar in the ileum. However, for isoleucine and leucine cultures, bacteria diversity was similar between the luminal fraction and tightly attached fraction, but significantly higher than in the loosely attached fraction. For glutamine and valine cultures, bacteria diversity was similar between the luminal and loosely attached fractions, but lower than that of tightly attached bacteria. After 30 subcultures, bacteria diversity in arginine, valine, glutamine, and leucine cultures varied between niches in the jejunum while being relatively stable in the ileum, consistent with those in the 24-h in vitro cultures. The findings may suggest that luminal bacteria tended to utilize free AA, while tightly attached adherent bacteria seemed in favor of AA synthesis, and that small intestinal microbes contributed little to BCAA metabolism. © 2014 Springer-Verlag.

Han W.,China Agricultural University | Tang L.,Peking University | Chen Y.,CAS Institute of Botany | Fang J.,Peking University
PLoS ONE | Year: 2013

Most previous studies have ascribed variations in the resorption of a certain plant nutrient to its corresponding environmental availability or level in tissues, regardless of the other nutrients' status. However, given that plant growth relies on both sufficient and balanced nutrient supply, the nutrient resorption process should not only be related to the absolute nutrient status, but also be regulated by the relative limitation of the nutrient. Here, based on a global woody-plants dataset from literature, we test the hypothesis that plants resorb proportionately more nitrogen (or phosphorus) when they are nitrogen (or phosphorus) limited, or similar proportions of nitrogen (N) and phosphorus (P) when co-limited by both nutrients (the relative resorption hypothesis). Using the N:P ratio in green foliage as an indicator of nutrient limitation, we found an inverse relationship between the difference in the proportionate resorption of N vs P and this foliar N:P ratio, consistent across species, growth-forms, and vegetationtypes globally. Moreover, according to the relative resorption hypothesis, communities with higher/lower foliar N:P (more likely P/N limited) tend to produce litter with disproportionately higher/lower N:P, causing a worsening status of P/N availability; this positive feedback may somehow be counteracted by several negative-feedback mechanisms. Compared to N, P generally shows higher variability in resorption efficiency (proportion resorbed), and higher resorption sensitivity to nutrient availability, implying that the resorption of P seems more important for plant nutrient conservation and N:P stoichiometry. Our findings elucidate the nutrient limitation effects on resorption efficiency in woody plants at the global scale, and thus can improve the understanding of nutrient resorption process in plants. This study also suggests the importance of the foliar N:P ratio as a key parameter for biogeochemical modeling, and the relative resorption hypothesis used to deduce the critical (optimal) N:P ratio for a specific plant community. © 2013 Han et al.

Wang Y.,China Agricultural University
IET Generation, Transmission and Distribution | Year: 2015

Spinning reserve plays an important role in balancing generation and demand mismatch within a short time interval. Probabilistic spinning reserve adequacy evaluation (PSRAE) is useful to aid operators in monitoring the adequacy of system upward spinning reserve exposed to unforeseen disturbances and making risk-adverse decisions for unit dispatching. As a short time period, for example, 30 s-15 min, is usually considered in PSRAE, the generating system in question is commonly of high reliability, which renders naive non-sequential Monte Carlo methods inefficient. In this study, the high reliability phenomenon of generating systems is explained through a toy case study, thereafter, aiming to develop an efficient method for PSRAE, a simulation method based on the cross-entropy which has been widely applied in many areas to improve naive Monte Carlo methods for tackling rare-event simulation issues, integrated with Markov chain Monte Carlo is proposed. The indices of loss of load probability and expected demand not supplied are used to quantify the spinning reserve inadequacy risk. Through case studies conducted on the RTS-79, usefulness of the PSRAE is discussed and the proposed method is proven to be superior to the classical cross-entropy method and thus could be taken as a candidate tool for the PSRAE to practical systems. © The Institution of Engineering and Technology 2015.

Luo Y.,China Agricultural University
Journal of Chinese Institute of Food Science and Technology | Year: 2013

The planting area of transgenic crops across the world is continuously increasing, the safety of transgenic food has become the consensus of authoritative institutions and mainstream scientific community. miRNA possible cross-border information exchange scientific discoveries, to make people think of their potential impact on the safety of genetically modified foods, but the current security evaluation method for this is still valid. The incident of golden rice in Hunan illustrates the importance of strengthening supervision and procedural justice. It is not necessary to worry about relaxing the standard of glyphosate residues within safe range, however, single dependence and abuse are not allowed. The second generation of transgenic crops will be more easily accepted by consumers. Transgenic technology is an important opportunity for developing countries to catch up with advanced technology of the world, which is not to be missed.

The giant dobsonfly species Acanthacorydalis orientalis (McLachlan, 1899) is endemic to China and is well-known because of its remarkable large adult body size and enlarged male mandibles. However, the immature stages of this species, as well as all other Acanthacorydalis species are poorly known. In this paper we describe the last-instar larvae and pupae of A. orientalis for the first time. Aspects of the bionomics of this species is also given. Copyright © 2013 Magnolia Press.

Meng X.,Zhejiang University of Technology | Pan Q.,China Agricultural University | Liu Y.,Beijing University of Chemical Technology
European Food Research and Technology | Year: 2012

In order to enhance the solubility and bioavailability of phytosterols (PS), cyclodextrin-PS (CD-PS) inclusion complexes were prepared and the properties of PS-β-cyclodextrin (PS-β-CD) and the inclusion mechanism of its derivative hydroxypropyl β-cyclodextrin (PS-HP-β-CD) in solution were also evaluated. The effects of crucial parameters on cyclodextrin-sterol inclusion efficiency were optimized, including solvent type, β-CD/PS molar ratio, temperature, PS content and reaction time; 92-98 % inclusion efficiency was achieved under the conditions of HP-β-CD/PS ratio 3:1-4:1, PS concentration 15-20 mM, temperature 50-55 °C, reaction time 12 h. For β-CD host, butanol was a good solvent for PS inclusion reaction. The properties of CD-PS inclusion complexes were characterized by differential scanning calorimetric, scanning electron microscopy, UV-Vis scanning spectrophotometer (UV-Vis) and fourier transform infrared spectroscopy (FT-IR), which demonstrated that there are intermolecular hydrogen bonds between PS and HP-β-CD in inclusion complex, resulting in the formation of amorphous form. To clarify the mechanism of the increase in the solubility and bioactivity of HP-β-CD-PS inclusion complexes, the structure of CD as well as the interaction of the HP-β-CD-PS inclusion formation was elucidated. The conclusions indicated that PS-HP-β-CD showed higher water solubility with greater solubilizing and complexing capabilities than PS-β-CD and PS itself. © 2012 Springer-Verlag Berlin Heidelberg.

Ortega D.L.,Purdue University | Wang H.H.,Purdue University | Wu L.,China Agricultural University | Olynk N.J.,Purdue University
Food Policy | Year: 2011

Food safety issues often arise from asymmetric information between consumers and suppliers with regards to product-specific attributes. Severe food safety scandals were observed recently in China. These events not only caused direct economic and life losses, but also created distrust in the Chinese food system domestically, as well as internationally. While much attention has focused on the problems plaguing the Chinese government's food inspection system, little research has been dedicated to analyzing Chinese consumers' concerns surrounding food safety. In this paper, we measure consumer preferences for select food safety attributes in pork and take food safety risk perceptions into account. Several choice experiment models, including latent class and random parameters logit, are constructed to capture heterogeneity in consumer preferences. Our results suggest that Chinese consumers have the highest willingness-to-pay for a government certification program, followed by third-party certification, a traceability system, and a product-specific information label. The results of this study call for the direct involvement of the Chinese government in the food safety system. A stricter monitoring system will not only improve consumer well-being in the short-run, but also restore consumers' trust leading to a social welfare increase in the long run. © 2010 Elsevier Ltd.

Fang H.,Tsinghua University | Han D.,HYDROCHINA Corporation | He G.,Tsinghua University | Chen M.,China Agricultural University
Journal of Hydrology | Year: 2012

After the Yangtze River was closed by the Three Gorges Project (TGP) in 2003, erosion occurred from the dam site to the river mouth, especially in the middle and lower reaches of the Yangtze River. However, in some local areas of Chenglingji reach which holds the key position for flood management, there is actually deposition in contrast to the expected erosion. In this paper, a one dimensional mathematical model of the river network with sediment transport is used as the tool to simulate flow and fluvial processes. The calculation domain is from Yichang, which is downstream of the dam, to Hankou, the controlling node of flood management, 694. km long in total. The model is calibrated based on the field data of hydrology and sediment transport during the period from October 2003 to October 2008. Then the model is utilized to simulate the erosion and deposition of the middle and lower reaches of the Yangtze River in the next two decades, and produce the results of a new river channel after river bed deformation occurs. The typical flood processes of 1954 and 1998 in the Yangtze River basin are used to check the flood management scheme for the research area, and results show that water storage of Three Gorges Reservoir (TGR) and a flood diversion program downstream of the Yangtze River should be taken into consideration. © 2012 Elsevier B.V.

Wang X.,China Agricultural University | Liu Y.,Huazhong Agricultural University | Yang P.,CAS Wuhan Botanical Garden
Frontiers in Plant Science | Year: 2012

Moss species Physcomitrella patens has been used as a model system in plant science for several years, because it has a short life cycle and is easy to be handled. With the completion of its genome sequencing, more and more proteomic analyses were conducted to study the mechanisms of P. patens abiotic stress resistance. It can be concluded from these studies that abiotic stresses could lead to the repression of photosynthesis and enhancement of respiration in P. patens, although different stresses could also result in specific responses. Comparative analysis showed that the responses to drought and salinity were very similar to that of abscisic acid, while the response to cold was quite different from these three. Based on previous studies, it is proposed that sub-proteomic studies on organelles or protein modifications, as well as functional characterization of those candidate proteins identified from proteomic studies will help us to further understand the mechanisms of abiotic stress resistance in P. patens. © 2012 Wang, Liu and Yang.

He L.-Y.,China Agricultural University
Computational Economics | Year: 2010

Empirical findings point out that the scaling and multiscaling properties can be found in many dealer markets. But how do these properties emerge from these financial markets? What are the dynamical causes for these nonlinear properties? Are they the results of random perturbations, or of the intrinsic characteristics of the markets? To answer these questions, first of all, I proposed a minimally structured agent-based model of a dealer market, and then conducted many experiments under several scenarios. This artificial financial market is occupied with heterogeneous agents characterized with bounded rationality and heterogeneity, and a dealer who is responsible for market liquidity and supply-demand balance. By means of simulations based on different scenarios, trading time series (prices, volumes, volatilities, etc) are generated and then are analyzed by Multi-Fractal Detrended Fluctuation Analysis (MF-DFA). Interestingly, the generated price series display scaling and multiscaling features, which is consistent with empirical findings in the real markets. Furthermore, the plausible explanation for these properties is nonlinear temporal correlation instead of probability distribution after the series are shuffled and phase randomized. All of the results imply that these properties of nonlinearity may derive from market participants' heterogeneity and mutual interactions; thereby, they may be the underlying characteristics of dealer markets. © 2010 Springer Science+Business Media, LLC.

Chang J.,China Agricultural University
Paiguan Jixie Gongcheng Xuebao/Journal of Drainage and Irrigation Machinery Engineering | Year: 2010

The experiment on cavitation and cavitation erosion of pump and turbine with silt-laden water as working medium was carried out. The experimental results show that lots of gas nuclei hiding in the gaps of sand surfaces grow up and form into the bubbles when pressure decreases, and then separate from the sand surface, cavitation happens finally. When sandiness and water temperature are constant, the cavitation pressure characteristics of silt-laden water depend on three important factors, the local altitude, sand mass concentration and sand radius. When the former two factors are constant, the incipient cavitation and critical cavitation pressure both increase with the decrease of sand radius. The gas nuclei number of silt-laden water is far greater than that of the clean water. When cavitation occurs in the silt-laden water, the jet-flow strength in sand water caused by the bubbles collapse is greater than that in the clean water. The two reasons above cause the cavitation damage of sediment-laden flow in water pump and turbine stronger than that of the clean water in the same device conditions. At present, the mistake that the vapor pressure of clean water at zero altitude is used to be of the cavitation pressure in the computation of the cavitating flow field and cavitation coefficient leads to serious inaccuracies of real results.

Wu Z.,Northern Arizona University | Zhang H.,China Agricultural University | Krause C.M.,Northern Arizona University | Cobb N.S.,Northern Arizona University
Climatic Change | Year: 2010

We examined both long-term climate variability and anthropogenic contributions to current climate change for Xinjiang province of northwest China. Xinjiang encompasses several mountain ranges and inter-mountain basins and is comprised of a northern semiarid region and a more arid southern region. Climate over the last three centuries was reconstructed from tree rings and temperature series were calculated for the past 50 years using weather station data. Three major conclusions from these analyses are: (1) Although temperature varied considerably in Xinjiang over the last 200 years, it was non-directional until the last 50 years when a substantial warming trend occurred; (2) The semiarid North Xinjiang was representative of the northern hemisphere climate, while the more arid South Xinjiang resembled the southern hemisphere climate, meanwhile, (3) The entire Xinjiang province captured the global-scale climate signal. We also compared human contributions to global change between North and South Xinjiang, including land cover/land use, population, and greenhouse gas production. For both regions, urban areas acted as heat islands; and large areas of grassland and forest were converted to barren land, especially in North Xinjiang. Additionally, North Xinjiang also showed larger increase in population and greenhouse gas emissions mainly associated with animal production than those in South Xinjiang. Although Xinjiang province is a geographically coupled mountain-basin system, the two regions have distinct climate patterns and anthropogenic activities related to land cover conversion and greenhouse gas production. © 2009 Springer Science+Business Media B.V.

Ma S.,China Agricultural University | Feng Z.,University of Texas-Pan American
International Journal of Bifurcation and Chaos | Year: 2011

In neural processing information, when we consider the finite propagation speed of signals in synapses, a time delay signal self-feedback mechanism is introduced into the well-known Rose-Hindmarsh Model. The Fold-Hopf bifurcation of this model is analyzed near equilibria. To discuss the singularity of this Codim-2 bifurcation, we discuss the normal form near the Fold-Hopf points on the center manifold. Bifurcations are studied and the stability is investigated by classifying neighborhood regimes near the Fold-Hopf points. Finally, as one of the most important electrical behaviors in neurons, the complex bursting-spiking firing modes associated with bifurcations are illustrated by numerical simulations. © 2011 World Scientific Publishing Company.

Qiu L.-C.,China Agricultural University
Wuli Xuebao/Acta Physica Sinica | Year: 2013

A projection-based incompressible smooth particle hydrodynamics (ISPH) is applied to the simulation of the deformation process of viscous liquid drop. In our numerical computation, the particle shifting technique is used to overcome particle clustering due to the tensile instability in SPH. In order to verify the proposed ISPH, numerical simulations of a viscous circle drop stretching and a viscous square drop rotating are carried out. The pressure distribution in the drop is obtained, and the deformation process of viscous liquid drop is correctly captured. Comparisons between numerical results and the analytical solutions in the literature are presented. The simulation results show that the projection-based ISPH with particle shifting technique can be used to simulate the deformation process of viscous liquid drop with stability and accuracy. © 2013 Chinese Physical Society.

Zhang S.,China Agricultural University | Yao C.,Yuncheng University
Materials Letters | Year: 2013

Ni-La(OH)3 nanotube arrays have been fabricated in a large scale via a simple electrochemical method without any hard templates and surfactants. The structure and morphology of the as-prepared Ni-La(OH)3 nanotube were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS). The FE-SEM and (HR)TEM images indicate that the obtained samples are relatively straight and regular with diameters of 150 nm. The maximum adsorption capacity of the as-prepared products for Congo red is about 96 mg g-1, suggesting its promising application in removing organic dye from wastewater. Meanwhile, this approach can provide a convenient route to synthesize other nanoarrays. © 2012 Elsevier B.V. All rights reserved.

Ho P.,University of Groningen | Ho P.,China Agricultural University | Azadi H.,International Institute for Asian Studies IIAS
Environmental Research | Year: 2010

Rangeland degradation, a worldwide problem, is serious in China, especially in the Northern provinces. To assess the pastoralists' perceptions toward rangeland trend and degradation, a survey was conducted in Ningxia, North China. Data were collected from a total of 284 pastoralists in six Ningxia counties. Findings showed that the majority of respondents believe the rangelands in Ningxia have been degraded, although there are some disparities among the counties that illustrate differing severity of degradation. Findings also clarified that the pastoralists have more knowledge about the "technical" and "supportive" aspects of conditions, while remaining less aware of "economic" and "management" factors of this issue. Yet, a high disparity was revealed between pastoralists' perceptions among the counties in this study. The correlation matrix showed that most of their perceptions do not act independently. Findings also showed that those pastoralists who believe that their rangeland trend is "improved" have broader management and social perceptions than those who believe their rangeland is "degraded". Finally, correlation analysis showed that the management and social perceptions have a negative correlation with degradation severity. Based on the findings, recommendations for possible interventions through extension/educational programs to diminish rangeland degradation are made. The programs are suggested to be presented in three packages including "management", "social", and "economic" issues in rangeland degradation. © 2009 Elsevier Inc. All rights reserved.

Gao X.,Texas A&M University | Wheeler T.,Texas A&M University | Li Z.,China Agricultural University | Kenerley C.M.,Texas A&M University | And 2 more authors.
Plant Journal | Year: 2011

Cotton is an important cash crop worldwide, and is a significant source of fiber, feed, foodstuff, oil and biofuel products. Considerable effort has been expended to increase sustainable yield and quality through molecular breeding and genetic engineering of new cotton cultivars. Given the recent availability of the whole-genome sequence of cotton, it is necessary to develop molecular tools and resources for large-scale analysis of gene functions at the genome-wide level. We have successfully developed an Agrobacterium-mediated virus-induced gene silencing (VIGS) assay in several cotton cultivars with various genetic backgrounds. The genes of interest were potently and readily silenced within 2 weeks after inoculation at the seedling stage. Importantly, we showed that silencing GhNDR1 and GhMKK2 compromised cotton resistance to the infection by Verticillium dahliae, a fungal pathogen causing Verticillium wilt. Furthermore, we developed a cotton protoplast system for transient gene expression to study gene functions by a gain-of-function approach. The viable protoplasts were isolated from green cotyledons, etiolated cotyledons and true leaves, and responded to a wide range of pathogen elicitors and phytohormones. Remarkably, cotton plants possess conserved, but also distinct, MAP kinase activation with Arabidopsis upon bacterial elicitor flagellin perception. Thus, using gene silencing assays, we have shown that GhNDR1 and GhMKK2 are required for Verticillium resistance in cotton, and have developed high throughput loss-of-function and gain-of-function assays for functional genomic studies in cotton. © 2011 Blackwell Publishing Ltd.

Lan W.-Z.,University of California at Berkeley | Lee S.-C.,University of California at Berkeley | Lee S.-C.,Chung - Ang University | Che Y.-F.,China Agricultural University | And 3 more authors.
Molecular Plant | Year: 2011

Arabidopsis K+ transporter 1 (AKT1) participates in K + uptake in roots, especially under low-K conditions. We recently identified a Ca2+ signaling pathway consisting of multiple calcineurin B-like calcium sensors (CBLs) and multiple target kinases (CBL-interacting protein kinases or CIPKs) that phosphorylate and activate AKT1, whereas a specific PP2C-type phosphatase inactivates CIPK-dependent AKT1 activity. In this study, we analyzed the interactions between PP2Cs and the CBL-CIPK pathway and found previously unsuspected mechanisms underlying the CBL-CIPK-PP2C signaling processes. The interaction between the CIPKs and PP2Cs involves the kinase domain of the CIPK component, in addition to the protein phosphatase interacting motif (PPI) in the regulatory domain. Furthermore, specific CBLs physically interact with and inactivate PP2C phosphatases to recover the CIPK-dependent AKT1 channel activity. These findings provide further insights into the signaling network consisting of CBL-CIPK-PP2C interactions in the activation of the AKT1 channel. © 2011 The Author.

Gu J.,Wageningen University | Yin X.,Wageningen University | Struik P.C.,Wageningen University | Stomph T.J.,Wageningen University | Wang H.,China Agricultural University
Journal of Experimental Botany | Year: 2012

Photosynthesis is fundamental to biomass production, but sensitive to drought. To understand the genetics of leaf photosynthesis, especially under drought, upland rice cv. Haogelao, lowland rice cv. Shennong265, and 94 of their introgression lines (ILs) were studied at flowering and grain filling under drought and well-watered field conditions. Gas exchange and chlorophyll fluorescence measurements were conducted to evaluate eight photosynthetic traits. Since these traits are very sensitive to fluctuations in microclimate during measurements under field conditions, observations were adjusted for microclimatic differences through both a statistical covariant model and a physiological approach. Both approaches identified leaf-to-air vapour pressure difference as the variable influencing the traits most. Using the simple sequence repeat (SSR) linkage map for the IL population, 1-3 quantitative trait loci (QTLs) were detected per trait-stage-treatment combination, which explained between 7.0% and 30.4% of the phenotypic variance of each trait. The clustered QTLs near marker RM410 (the interval from 57.3cM to 68.4cM on chromosome 9) were consistent over both development stages and both drought and well-watered conditions. This QTL consistency was verified by a greenhouse experiment under a controlled environment. The alleles from the upland rice at this interval had positive effects on net photosynthetic rate, stomatal conductance, transpiration rate, quantum yield of photosystem II (PSII), and the maximum efficiency of light-adapted open PSII. However, the allele of another main QTL from upland rice was associated with increased drought sensitivity of photosynthesis. These results could potentially be used in breeding programmes through marker-assisted selection to improve drought tolerance and photosynthesis simultaneously. © 2011 The Author(s).

Zheng Z.,China Agricultural University | Henneberry S.R.,Oklahoma State University
Agribusiness | Year: 2011

Price and income elasticities are estimated for ten major food groups across low-, medium-, and high-income classes, using the 2004 China urban household survey data for Jiangsu province. Demand parameters are estimated using an incomplete demand system (the LinQuad model). Results of this study show that for the majority of the studied food categories, the demand for the low-income group is found to be more income and own-price elastic; while the demand for the high-income group is found to be less income and own-price elastic. Therefore, the null hypothesis of constant price and income elasticities of demand is rejected in this study. [EconLit citations: D120, R220, Q180]. © 2010 Wiley Periodicals, Inc.

Van der Ploeg J.D.,Wageningen University | Van der Ploeg J.D.,China Agricultural University | Ventura F.,University of Perugia
Current Opinion in Environmental Sustainability | Year: 2014

Farming styles are distinctive patterns through which agricultural production is organized and developed. Different styles result in different levels of intensity and sustainability. This means that encouraging and stimulating specific farming styles might result in considerable agricultural development and growth of total food production. Currently, peasant-like styles of farming offer a great deal of promise for feeding the world in a sustainable way. © 2014 Elsevier B.V.

Duan Y.-E.,China Agricultural University
Advanced Materials Research | Year: 2012

The Internet of Things (IOT) is a self-styled term to describe a new network technology that make all of objects be able to communicate in the Internet via RFID and different sensor devices. It is the basis of intelligent management. In this paper, the concept of IOT was first explained from the side of technology and application etc. Then the model and architecture of IOT were analyzed in detail. Finally, this paper introduced the specific application of IOT in Urban agriculture, and gave the application frame model in agricultural production and agricultural product supply system. © (2012) Trans Tech Publications.

Nord E.A.,Pennsylvania State University | Zhang C.,China Agricultural University | Lynch J.P.,Pennsylvania State University
Functional Plant Biology | Year: 2011

Plants are reported to over-proliferate roots in response to belowground competition, thereby reducing reproductive biomass. This has been cited as an instance of the 'tragedy of the commons'. Many of the studies that report this response suggest that plants can sense neighbours and discriminate between 'self' and 'non-self' roots. To test the alternate hypothesis that root responses to a neighbouring plant are mediated by resource depletion, common bean plants were supplied with the same phosphorus (P) fertiliser dose in varying rooting volumes, or with neighbouring plants separated by plastic film, nylon mesh, or no barrier to vary access to a neighbour. Phosphorus concentration, but not the presence of a neighbour or rooting volume, strongly influenced biomass allocation to roots. Root architecture was significantly altered by both neighbours and P availability. When exposed to the roots of a neighbour, plants altered the vertical and horizontal distribution of roots, placing fewer roots in soil domains occupied by roots of a neighbour. These results support the hypothesis that root responses to neighbouring plants are mediated by resource depletion by the neighbour rather than sensing of 'non-self' roots and show that the presence of a neighbour may affect root architecture without affecting biomass allocation to roots. © 2011 CSIRO.

Liu Z.,China Agricultural University | Zhang C.,Tsinghua University | Lu Y.,Tsinghua University | Wu X.,Tsinghua University | And 3 more authors.
Bioresource Technology | Year: 2013

Hythane (H2+CH4) has attracted growing attention due to its versatile advantages as, for instance vehicle fuel. Biohythane consisting of biohydrogen and biomethane via two-stage fermentation is a potential high-value solution for the valorization of waste biomass resources and probably an alternative to the fossil based hythane. However, the significance and application potential of biohythane have not yet been fully recognized. This review focuses on the progress of biohydrogen and subsequent biomethane fermentation in terms of substrate, microbial consortium, reactor configuration, as well as the H2/CH4 ratio from the perspective of the feasibility of biohythane production in the past ten years. The current paper also covers how controls of the microbial consortium and bioprocess, system integration influence the biohythane productivity. Challenges and perspectives on biohythane technology will finally be addressed. This review provides a state-of-the-art technological insight into biohythane production by two-stage dark fermentation from biomass. © 2012 Elsevier Ltd.

Han W.X.,Peking University | Han W.X.,China Agricultural University | Fang J.Y.,Peking University | Reich P.B.,University of Minnesota | And 3 more authors.
Ecology Letters | Year: 2011

Understanding variation of plant nutrients is largely limited to nitrogen and to a lesser extent phosphorus. Here we analyse patterns of variation in 11 elements (nitrogen/phosphorus/potassium/calcium/magnesium/sulphur/silicon/iron/sodium/manganese/aluminium) in leaves of 1900 plant species across China. The concentrations of these elements show significant latitudinal and longitudinal trends, driven by significant influences of climate, soil and plant functional type. Precipitation explains more variation than temperature for all elements except phosphorus and aluminium, and the 11 elements differentiate in relation to climate, soil and functional type. Variability (assessed as the coefficient of variation) and environmental sensitivity (slope of responses to environmental gradients) are lowest for elements that are required in the highest concentrations, most abundant and most often limiting in nature (the Stability of Limiting Elements Hypothesis). Our findings can help initiate a more holistic approach to ecological plant nutrition and lay the groundwork for the eventual development of multiple element biogeochemical models. © 2011 Blackwell Publishing Ltd/CNRS.

Zhang H.,China Agricultural University | Liu K.,Gothenburg University
Human Reproduction Update | Year: 2015

BACKGROUND: The first small follicles to appear in the mammalian ovaries are primordial follicles. The initial pool of primordial follicles serves as the source of developing follicles and oocytes for the entire reproductive lifespan of the animal. Although the selective activation of primordial follicles is critical for female fertility, its underlying mechanisms have remained poorly understood. METHODS: A search of PubMed was conducted to identify peer-reviewed literature pertinent to the study of mammalian primordial follicle activation, especially recent reports of the role of primordial follicle granulosa cells (pfGCs) in regulating this process. RESULTS: In recent years, molecular mechanisms that regulate the activation of primordial follicles have been elucidated, mostly through the use of genetically modified mouse models. Several molecules and pathways operating in both the somatic pfGCs and oocytes, such as the phosphatidylinositol 3 kinase (PI3K) and the mechanistic target of rapamycin complex 1 (mTORC1) pathways, have been shown to be important for primordial follicle activation. More importantly, recent studies have provided an updated view of how exactly signaling pathways in pfGCs and in oocytes, such as the KIT ligand (KL) and KIT, coordinate in adult ovaries so that the activation of primordial follicles is achieved. CONCLUSIONS: In this review, we have provided an updated picture of how mammalian primordial follicles are activated. The functional roles of pfGCs in governing the activation of primordial follicles in adulthood are highlighted. The in-depth understanding of the cellular and molecular mechanisms of primordial follicle activation will hopefully lead to more treatments of female infertility, and the current progress indicates that the use of existing primordial follicles as a source for obtaining fertilizable oocytes as a new treatment for female infertility is just around the corner. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved.

Che L.,China Agricultural University | Chen X.D.,Monash University
Drying Technology | Year: 2010

In this article, a method is presented to measure the moisture content of single droplets/particles under air convection based on accurate measurement of the droplet/particle diameter and temperature. Experiments on droplets/particles of aqueous glucose were conducted as an example, and the results obtained support validity of such a method. © 2010 Taylor & Francis Group, LLC.

Li F.-F.,China Agricultural University | Qiu J.,Tsinghua University
Applied Energy | Year: 2015

The most striking feature of the solar energy is its intermittency and instability resulting from environmental influence. Hydropower can be an ideal choice to compensate photovoltaic (PV) power since it is easy to adjust and responds rapidly with low cost. This study proposed a long-term multi-objective optimization model for integrated hydro/PV power system considering the smoothness of power output process and the total amount of annual power generation of the system simultaneously. The PV power output is firstly calculated by hourly solar radiation and temperature data, which is then taken as the boundary condition for reservoir optimization. For hydropower, due to its great adjustable capability, a month is taken as the time step to balance the simulation cost. The problem dimension is thus reduced by decoupling hydropower and PV power in time scales. The modified version of Non-dominated Sorting Genetic Algorithm (NSGA-II) is adopted to optimize the multi-objective problem. The proposed model was applied to the Longyangxia hydro/PV hybrid power system in Qinghai province of China, which is supposed to be the largest hydro/PV hydropower station in the world. The results verified that the hydropower is an ideal compensation resource for the PV power in nature, especially in wet years, when the solar radiation decreases due to rainfalls while the water resource is abundant to be allocated. The power generation potential is provided for different hydrologic years, which can be taken to evaluate the actual operations. The proposed methodology is general in that it can be used for other hydro/PV power systems than those studied here. © 2015 Elsevier Ltd.

Wu J.,Beijing Technology and Business University | Xu Y.,China Agricultural University
Nongye Jixie Xuebao/Transactions of the Chinese Society of Agricultural Machinery | Year: 2011

Competitive adaptive reweighted sampling (CARS) method was employed to improve the prediction accuracy of the NIR quantitative model of four kinds of fatty acid (palmitic acid, stearic acid, oleic acid and linoleic acid) in edible oil.Predict concentration residual method was employed to detect the outlier before preprocessing the spectroscopy by normalization.The key variables were selected by CARS method.The partial least squares (PLS) calibration models of four kinds of fatty acid were established respectively in the optimal conditions, and compared with the results using OPUS software. Determination coefficient (R2), root mean square error of cross validation(RMSECV)and root mean square error of prediction (RMSEP) were used to evaluate the quality of the modes.The results showed that better prediction was obtained by CARS. The result showed that using CARS could effectively simplify the model and the less number of wavelength variables selected could be reference for developing filter spectrometer of edible oil.

Xing Y.,University of Science and Technology Beijing | Chen W.-H.,Beijing Institute of Technology | Jia W.,China Agricultural University | Zhang J.,Chinese University of Hong Kong
Journal of Experimental Botany | Year: 2015

Superoxide dismutases (SODs) are involved in plant adaptive responses to biotic and abiotic stresses but the upstream signalling process that modulates their expression is not clear. Expression of two iron SODs, FSD2 and FSD3, was significantly increased in Arabidopsis in response to NaCl treatment but blocked in transgenic MKK5-RNAi plant, mkk5. Using an assay system for transient expression in protoplasts, it was found that mitogen-activated protein kinase kinase 5 (MKK5) was also activated in response to salt stress. Overexpression of MKK5 in wild-type plants enhanced their tolerance to salt treatments, while mkk5 mutant exhibited hypersensitivity to salt stress in germination on salt-containing media. Moreover, another kinase, MPK6, was also involved in the MKK5-mediated iron superoxide dismutase (FSD) signalling pathway in salt stress. The kinase activity of MPK6 was totally turned off in mkk5, whereas the activity of MPK3 was only partially blocked. MKK5 interacted with the MEKK1 protein that was also involved in the salt-induced FSD signalling pathway. These data suggest that salt-induced FSD2 and FSD3 expressions are influenced by MEKK1 via MKK5-MPK6-coupled signalling. This MAP kinase cascade (MEKK1, MKK5, and MPK6) mediates the salt-induced expression of iron superoxide dismutases. © 2015 The Author.

Gao H.,China Agricultural University | Shreeve J.M.,University of Idaho
Angewandte Chemie - International Edition | Year: 2015

New derivatives of 1,1-diamino-2, 2-dinitroethene (FOX-7) are reported. These highly oxygen- and nitrogen-rich compounds were fully characterized using IR and multinuclear NMR spectroscopy, elemental analysis (EA), and differential scanning calorimetry (DSC). X-ray structure determination of (E)-1,2-bis{(E)-2-chloro-1-(chloroimino)-2,2-dinitroethyl}diazene) (10), N1, N2-dichloro-1, 2-diazenedicarboximidamide (11), and (E,E)-N,N′-1,2-ethanediylidenebis(2, 2-dinitro-2-chloro-ethanamine) (12) was helpful in their characterization. Heats of formation (HOF) were calculated (Gaussian03) and combined with experimental densities to estimate the detonation velocities (D) and pressures (P) of the high-energy-density materials (HEDMs) (EXPLO5, v6.01). The compounds exhibit good thermal stability, high density, positive HOF, acceptable oxygen balances, and excellent detonation properties, which often are superior to that of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX). Fox in a box: New derivatives created from 1,1-diamino-2, 2-dinitroethene (FOX-7) often have properties superior to those of RDX. The compounds exhibit good thermal stability, high density, positive heats of formation, an acceptable oxygen balance, and excellent detonation properties. These findings contribute to the value of FOX-7 as an energetic precursor. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Qi S.,China Agricultural University | Casida J.E.,University of California at Berkeley
Pesticide Biochemistry and Physiology | Year: 2013

Anthranilic and phthalic diamides exemplified by chlorantraniliprole (Chlo) or cyantraniliprole (Cyan) and flubendiamide (Flu), respectively, are the newest major chemotype of insecticides with outstanding potency, little or no cross resistance with other classes and low mammalian toxicity. They are activators of the ryanodine (Ry) receptor (RyR)-Ca2+ channel, based on Ca2+ flux and electrophysiology investigations. The goal of this study is to define species differences in the degree and mechanisms of diamide selective action by radioligand specific binding studies at the [3H]Ry, [3H]Chlo and [3H]Flu sites. The [3H]Ry site is observed in muscle of lobster, rabbit and four insect species (Musca domestica, Apis mellifera, Heliothis virescens and Agrotis ipsilon) whereas the [3H]Chlo site is evident in the four insects and the [3H]Flu site in only the two lepidoptera (Agrotis and Heliothis). [3H]Ry binding is significantly stimulated by Chlo, Cyan and Flu with the insects (except Flu with Musca) but not the lobster and rabbit. [3H]Chlo binding is stimulated by Ry and Flu in Musca and Apis but not in the lepidoptera, while Flu and Cyan are inhibitory. [3H]Flu binding is strongly inhibited by Chlo and Cyan in Agrotis and Heliothis. [3H]Chlo and [3H]Flu binding are not dependent on added Ca2+ or ATP in Heliothis and Agrotis whereas the other radioligand-receptor combinations are usually enhanced by Ca2+ and ATP. More generally, there are species differences in the Ry, Chlo and Flu binding sites of the RyR that may confer selective toxicity and determine target site cross resistance mechanisms. © 2013.

Thottempudi V.,University of Idaho | Gao H.,China Agricultural University | Shreeve J.M.,University of Idaho
Journal of the American Chemical Society | Year: 2011

Various new polynitro-1,2,4-triazoles containing a trinitromethyl group were synthesized by straightforward routes. These high nitrogen and oxygen-rich compounds were fully characterized using IR and multinuclear NMR spectroscopy, elemental analysis, natural bonding orbital (NBO) analysis, and differential scanning calorimetry (DSC) and, in the case of 12, with single crystal X-ray structuring. The heats of formation for all compounds were calculated with Gaussian 03 (revision D.01) and then combined with experimentally determined densities to determine detonation pressures (P) and velocities (D) of the energetic materials (Cheetah 5.0). They exhibit high density, good thermal stability, acceptable oxygen balance, positive heat of formation, and excellent detonation properties, which, in some cases, are superior to those of TNT, RDX, and HMX. © 2011 American Chemical Society.

Nie J.,Tianjin University | Guo H.-C.,China Agricultural University | Cahard D.,INSA Rouen | Ma J.-A.,Tianjin University | Ma J.-A.,CAS Shanghai Institute of Organic Chemistry
Chemical Reviews | Year: 2011

Trifluoromethyl aldimines have emerged as powerful building blocks to construct important molecules in many fields of application. The protecting group on the oxygen was installed to prevent the ring closure into the corresponding oxazolidine during preparation of the substrate. This approach toward Cathepsin K inhibitors gives high diastereoselectivity, is suitable for multigram-scale synthesis, is complementary to the in situ generation of imines from oxazolidines. Trifluoroacetaldehyde imines featuring a chiral enantiopure auxiliary present the disadvantage of being self-immolative for the auxiliary because the nitrogen atom is incorporated in the final product and the stereogenic center is lost during the removal step. Trifluoropyruvates are nonenolizable ketones and more electrophilic than ethyl pyruvate due to the electronwithdrawing trifluoromethyl group.

Tian J.,South China Agricultural University | Wang X.,South China Agricultural University | Tong Y.,CAS Institute of Genetics and Developmental Biology | Chen X.,China Agricultural University | Liao H.,South China Agricultural University
Current Opinion in Biotechnology | Year: 2012

Phosphorus (P) is one of the three macronutrients for plants. Because of its low mobility and high fixation in soils, low P availability is a worldwide constraint for crop productivity. Molecular biology provides great opportunities to improve P efficiency in plants. However, transgenic plants cannot be commercialized before integrating all the knowledge on bottlenecks for improving P efficiency of crops/pastures. This review intends to summarize the main strategies of bioengineering to improve P efficiency of crops/pastures, including conventional and molecular assisted breeding, identification and application of key genes for biotech plants. It highlights recent advances in the understanding of improving P efficiency through the integration of bioengineering with P fertilization and cultivation management. © 2012 Elsevier Ltd.

Zhao H.,Shanghai JiaoTong University | Xu Z.,Shanghai JiaoTong University | Qin H.,Shanghai JiaoTong University | Gao Z.,Nanjing Medical University | And 3 more authors.
Biochemical Journal | Year: 2014

CRC (colorectal cancer) is one of the most malignant tumours in both developing and developed countries. It is estimated that 60% of CRC patients have liver metastasis. In the present study, we show that miR-30b is an important regulator in human CRC migration and invasion, which are vital steps in CRC liver metastasis. miR-30b was significantly down-regulated in primary CRC specimens compared with normal tissues. Furthermore, miR-30b was much lower in liver metastasis tissues than in CRCs. We validated SIX1 (SIX homeobox 1), a member of the SIX homeodomain family of transcription factors and an EMT (epithelial-mesenchymal transition)-promoting gene, as the directtarget of miR-30b. Forced expression of miR-30b inhibited CRCcell migration and invasion in vitro via its target gene SIX1. Furthermore, an inverse correlation between expression of SIX1 and miR-30b has been observed both in primary CRC specimens and liver metastasis. Taken together, miR-30b plays an important role in mediating metastatic related behaviour in CRC. miR-30b may serve as a potential diagnostic marker and therapeutic target for patients with CRC in the future. © 2014 Biochemical Society.

Zhong L.,Guangdong Ocean University | Liu L.,China Agricultural University | Yang J.,Guangdong Ocean University
Environmental Earth Sciences | Year: 2012

The heavy metal accumulation in soils caused by industrialization has attracted broad attention. To evaluate the soil environmental quality of Xiangyin County, an important food production base in China, 99 top paddy soil samples were analyzed for total concentrations of As, Cd, Cr, Cu, Hg, Ni, Zn and Pb. Kriging interpolation was used to determine the spatial distribution of the metals. The assessment of soil environmental quality was performed according to pollution index methods. As the results showed, except for Cu, Cr and Ni, the mean concentrations of Zn, Pb, Cd, As and Hg in soils were elevated to different extents when compared with the background values. Moreover, except for Cd, contents of seven other elements in most soil samples were below the Class II criteria for Chinese environmental quality standards, which established the maximum allowable concentration of heavy metal in the farmland. Therefore, the soils were believed to be polluted mainly by Cd. All of the elements showed a similar spatial distribution pattern with low contents in the east upland area, and high contents in the middle by the west area, located close to Dongting lake. The long-term practice of using the Xiangjiang river as irrigation water was believed to be the main reason resulting in the enrichment of heavy metals in soils around Dongting lake. In addition, the evaluation results showed that about 45. 8, 51. 1 and 3. 1 % of the study area were classified as slightly, moderately and seriously polluted with Cd, respectively. As for the other seven elements, soil environmental quality was fairly well because of their grades belonging to clean or excellent. By integration of the assessment results for individual elements, it was found that about 3. 8 % of the study area was clean, 82. 2 % was slightly polluted and 14. 1 % was moderately polluted. On the whole, most of the study area was at safe and guarded level. However, appropriate measures still should be adopted to control the levels of heavy metals in agricultural soils. The findings obtained in this study were useful for establishing policies for protecting the local soil environments and guaranteeing the food quality as well as the people's health. © 2012 Springer-Verlag.

Song C.-F.,University of Tsukuba | Kitamura Y.,University of Tsukuba | Li S.-H.,University of Tsukuba | Jiang W.-Z.,China Agricultural University
International Journal of Greenhouse Gas Control | Year: 2013

With the development of CO2 capture technologies, the cryogenic approach provides a promising alternative for greenhouse effect mitigation. In previous work, a novel CO2 capture process was developed based on Stirling coolers (SC). However, the properties of frosted CO2 that deposits onto the heat exchanger of SC are not completely understood but it plays an important role as a heat transfer medium and affects subsequent CO2 deposition. In order to improve the system performance and capture efficiency, a thorough analysis of the CO2 frost process becomes especially significant. Based on this aim, numerical and experimental analysis of CO2 frost formation in the cryogenic capture process has been investigated in the present work. The results show that the frosted CO2 layer significantly influences the heat transfer between the gas stream and cooling fins. Over time (from 0 to 60min), the thickness of the frost layer increased from 0 to 3.0mm. The thermal conductivity increased from 0 to 0.4W/(mK). When the flow rate was set at 1L/min, the temperature of the cold head of the SC varied from -105.2°C to -102.1°C. When the flow rate was 3L/min, the temperature rose from -106.3°C to -98.0°C. © 2012 Elsevier Ltd.

Li J.-Q.,China Agricultural University | Andersson P.G.,University of Stockholm | Andersson P.G.,University of KwaZulu - Natal
Chemical Communications | Year: 2013

A bidentate iridium NHC-phosphine complex has been developed and applied to the N-monoalkylation of aromatic amines with a wide range of primary alcohols and to the N-heterocyclization of amino alcohols. This reaction resulted in high isolated product yields, even at room temperature and under solvent-free conditions. © The Royal Society of Chemistry 2013.

Wang Y.W.,Oklahoma State University | Wang Y.W.,China Agricultural University | Samuels T.D.,Oklahoma State University | Wu Y.Q.,Oklahoma State University
Theoretical and Applied Genetics | Year: 2011

Switchgrass, Panicum virgatum L., a native to the tall grass prairies in North America, has been grown for soil conservation and herbage production in the USA and recently widely recognized as a promising dedicated cellulosic bioenergy crop. A large amount of codominant molecular markers including simple sequence repeats (SSRs) are required for the construction of linkage maps and implementation of molecular breeding strategies to develop superior switchgrass cultivars. The objectives of this study were (1) to identify SSR-containing clones and to design PCR primer pairs (PPs) in SSR-enriched genomic libraries, and (2) to validate and characterize the designed SSR PPs. Five genomic SSR enriched libraries were constructed using genomic DNA of 'SL93 7 × 15', a switchgrass genotype selected in an Oklahoma State University (OSU) southern lowland breeding population. A total of 3,046 clones from four libraries enriched in (CA/TG)n, (GA/TC)n, (CAG/CTG)n and (AAG/CTT)n SSR repeats were sequenced at the OSU Core Facility. From the sequences, we isolated 1,300 unique SSR-containing clones, from which we designed 1,398 PPs using SSR Locator V. 1 software. Among the designed PPs, 1,030 (73. 7%) amplified reproducible and strong bands with expected fragment size, and 802 detected polymorphic alleles, in SL93 7 × 15 and 'NL94 16 × 13', two parents of one mapping population. All of the four libraries contained a high rate of perfect SSR repeat types, ranging from 62. 7 to 76. 2%. Polymorphism of the effective SSR markers was also tested in two lowland and two upland switchgrass cultivars, encompassing 'Alamo' and 'Kanlow', and 'Blackwell' and 'Dacotah', respectively. The developed SSR markers should be useful in genetic and breeding research in switchgrass. © 2010 Springer-Verlag.

Ju Z.,Chinese Academy of Sciences | Ren T.,China Agricultural University | Hu C.,Chinese Academy of Sciences
Soil Science Society of America Journal | Year: 2011

Soil thermal conductivity (λ) is strongly influenced by soil water content as well as the arrangement of solid particles in soil. In this study we investigated the influences of soil aggregation on soil thermal conductivity at relatively higher water contents by the thermo-time domain reflectometry (TDR) technique. The relationship between thermal conductivity and water content (θV) was measured for both aggregated (<2 mm) and non-aggregated (<0.1 mm) loam and clay loam soils using two different experimental approaches: continuous vs. non-continuous measurements. The results from the continuous measurement showed that thermal conductivity was significantly higher in the non-aggregated soils than in the aggregated soils at intermediate water contents. This is explained by the formation of intra-aggregate pores in aggregated soils that decreases the contacts and heat flow between aggregates. Alternatively the non-aggregated soils have a relatively uniform pore system that enhances bridging between neighboring particles through pore water, thus improves heat conduction. For the non-aggregated soils, relatively larger bulk density increase during the drying process also contributes to the greater thermal conductivity than that of aggregated soils. The results from the non-continuous approach, however, showed similar thermal conductivity values for the aggregated and non-aggregated soils, which was possibly caused by aggregate reformation in nonaggregated samples during soil mixing and packing. © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA All rights reserved.

Cai J.,National Tsing Hua University | Cai J.,Ghent University | Cai J.,National Cheng Kung University | Cai J.,CAS Institute of Botany | And 4 more authors.
Nature genetics | Year: 2015

Orchidaceae, renowned for its spectacular flowers and other reproductive and ecological adaptations, is one of the most diverse plant families. Here we present the genome sequence of the tropical epiphytic orchid Phalaenopsis equestris, a frequently used parent species for orchid breeding. P. equestris is the first plant with crassulacean acid metabolism (CAM) for which the genome has been sequenced. Our assembled genome contains 29,431 predicted protein-coding genes. We find that contigs likely to be underassembled, owing to heterozygosity, are enriched for genes that might be involved in self-incompatibility pathways. We find evidence for an orchid-specific paleopolyploidy event that preceded the radiation of most orchid clades, and our results suggest that gene duplication might have contributed to the evolution of CAM photosynthesis in P. equestris. Finally, we find expanded and diversified families of MADS-box C/D-class, B-class AP3 and AGL6-class genes, which might contribute to the highly specialized morphology of orchid flowers.

Shen Y.,Kansas State University | Yuan W.,Kansas State University | Pei Z.,Kansas State University | Mao E.,China Agricultural University
Applied Biochemistry and Biotechnology | Year: 2010

The influences of urea, yeast extract, and nitrate as the nitrogen source on heterotrophic growth of four strains of Chlorella protothecoides were investigated in 9-day feed-batch cultures. Biomass dry weight concentration (DWC) and lipid yield (LY) of the four strains in all media were compared. The highest LY in 9 days was 654 mg/L/day by UTEX 255 in 2.4 g/L KNO3 medium with a biomass DWC of 11.7 g/L and lipid content of 50.5%. Using green autotrophic seeds instead of yellow heterotrophic seeds improved the biomass DWC (13.1 vs. 11.7 g/L), LY (850 vs. 654 mg/L/day), and lipid to glucose consumption ratio (0.607 vs. 0.162). Moreover, 17.0 g/L DWC and 489 mg/L/day LY were obtained from the sequentially mixed-nitrogen medium, and the lipid to glucose consumption ratio was improved to 0.197 from 0.162 in 2.4 g/L nitrate medium and from 0.108 in 4.2 g/L yeast extract medium in the first batch. © 2009 Humana Press.

Joo Y.-H.,University of Idaho | Gao H.,China Agricultural University | Zhang Y.,University of Idaho | Shreeve J.M.,University of Idaho
Inorganic Chemistry | Year: 2010

Recently extensive research has focused on replacing toxic hydrazine, monomethylhydrazlne, and unsymmetrlcal dlmethylhydrazlne as liquid propellant fuels. 2-Azido-N,N-dimethylethylamine (1) is a good candidate to replace hydrazine derivatives in certain hypergollc fuel applications. Energetic Ionic liquids that contain the 2-azido-N,N,Ntrimethylethylammonium cation with nltrocyanamide, dicyanamide, dinitramide, orazlde anion have been successfully synthesized In good yields by metathesis reactions. Ionic liquids have received considerable attention as energetic materials. The replacement of hydrazine with tertiary ammonium salts Is especially attractive since many Ionic liquids are models for green chemistry. In this work, new azide-functlonallzed Ionic liquids are demonstrated to exhibit hypergollc activity with such oxidizers as 100% nitric acid or nitrogen tetraoxide (NTO). ©2010 American Chemical Society.

Wurschum T.,University of Hohenheim | Liu W.,University of Hohenheim | Liu W.,China Agricultural University | Maurer H.P.,University of Hohenheim | And 2 more authors.
Theoretical and Applied Genetics | Year: 2012

Detection of QTL in multiple segregating populations is of high interest as it includes more alleles than mapping in a single biparental population. In addition, such populations are routinely generated in applied plant breeding programs and can thus be used to identify QTL which are of direct relevance for a marker-assisted improvement of elite germplasm. Multiple-line cross QTL mapping and joint linkage association mapping were used for QTL detection. We empirically compared these two different biometrical approaches with regard to QTL detection for important agronomic traits in nine segregating populations of elite rapeseed lines. The plants were intensively phenotyped in multi-location field trials and genotyped with 253 SNP markers. Both approaches detected several additive QTL for diverse traits, including flowering time, plant height, protein content, oil content, glucosinolate content, and grain yield. In addition, we identified one epistatic QTL for flowering time. Consequently, both approaches appear suited for QTL detection in multiple segregating populations. © 2011 Springer-Verlag.

Gao H.,China Agricultural University | Shreeve J.M.,University of Idaho
Journal of Materials Chemistry | Year: 2012

Borane compounds which are hydrogen storage materials are hypergolic with white fuming nitric acid as oxidizer. When dissolved in ionic liquids, the borane solutions exhibit ignition delay times which are superior to any known hypergolic ionic liquids. These borane-ionic liquid solutions appear to be the brightest hope so far to replace hydrazine and its derivatives as fuels in hypergolic propellant systems. © 2012 The Royal Society of Chemistry.

Xiong Y.,China Agricultural University
Journal of Hydrology | Year: 2014

Different from classic wetting patterns, saturation overshoot (also called saturation-bump or non-monotonic saturation profile) is widely observed in unsaturated porous media. Saturation overshoot is the case of a high and uniform water content zone directly behind the wetting front followed by another region with a low and uniform saturation. This paper reviews recent research progress on this anomalous phenomenon, focusing on experimental observations and theoretical model development. Experimental conditions for the occurrence of overshoot generally coincide with those of gravity-driven fingered flow. Saturation overshoot is associated with the corresponding capillary pressure overshoot. The Richards equation in its basic form cannot describe the non-monotonic saturation field due to its parabolic nature and incompleteness in physics. Several attempts to modify the Richards equation and other approaches proposed recently have been reviewed and assessed. The knowledge gaps and research opportunities on saturation overshoot are summarized at the end. © 2014 Elsevier B.V.

Liu Y.,Beijing Technology and Business University | Hu X.,China Agricultural University | Zhao X.,Beijing Academy of Agriculture and Forestry Sciences | Song H.,Beijing Technology and Business University
Innovative Food Science and Emerging Technologies | Year: 2012

The aim of this study was to investigate the combined effect of high pressure carbon dioxide (HPCD) and mild heat treatment on the overall quality of watermelon juice. The residual activity of polyphenoloxidase (PPO), peroxidase (POD), and pectin methylesterase (PME) decreased with pressure and treatment time after HPCD and heat treatment. The total color difference (E) value was greater than 3.5, suggesting the significant change of color. Browning degree (BD) decreased with pressure and treatment time; pH and lycopene content of HPCD-treated juice slightly decreased; cloudiness and titratable acidity (TA) increased; and viscosity of 10 and 20 MPa treated juice at 31.62 1 s - 1 did not change. While after control treatment, the residual activity of enzymes and BD decreased slightly; cloudiness decreased greatly; pH, TA, lycopene content, and color were stable. HPCD and mild heat treatment inactivated enzyme activities drastically which affected the shelf life and quality of watermelon juice greatly during storage. And it increased cloudy stability that was the important parameter to influence appearance of juice. Overall, HPCD treatment has greater advantages to maintain the quality of watermelon juice. Industrial relevance: The application of high pressure carbon dioxide (HPCD) processing on several food products has already been proven to be successful for pasteurization. HPCD processing to inactivate endogenous enzymes and retain quality of food needs to be further studied. Studies dealing with the combination effect of pressure and mild heat conditions on enzyme activities and quality parameters are relevant to understand the prospects for watermelon juice processing. © 2011 Elsevier Ltd.

Nishinari K.,Hubei Engineering University | Fang Y.,Hubei Engineering University | Guo S.,China Agricultural University | Phillips G.O.,Hubei Engineering University
Food Hydrocolloids | Year: 2014

Composition of soybean proteins is briefly described. Gels and gelling processes of soybean proteins and other functionalities such as colloidal properties and emulsifying properties are described. The effects of temperature, pH, ionic strength, processing conditions such as high pressure, ultrasonic treatment, utilisation of enzyme, chemical modification are also described since they have been found useful to improve the processing and final product. © 2014 Elsevier Ltd.

Qiu L.-C.,China Agricultural University
Procedia Engineering | Year: 2015

A two-dimensional coupling model of the discrete element method (DEM) and the lattice Boltzmann method (LBM) was used to study the fluid flow through porous media. The fluid flow was modeled at a mesoscale level by using the LBM. The particle motion was modeled at microscale level by means of the DEM. The interfacial interaction between the fluid and the solids is resolved by an implicit immersed boundary method (IBM). The proposed method has validated by comparing the numerical results with theoretic solutions in the literature. It demonstrates the ability of the proposed method to simulate fluid flows through complex porous media. © 2015 The Authors.

Duan J.,Chinese Academy of Agricultural Sciences | Duan J.,China Agricultural University | Xia C.,Chinese Academy of Agricultural Sciences | Zhao G.,Chinese Academy of Agricultural Sciences | And 2 more authors.
BMC Genomics | Year: 2012

Background: Rapid advances in next-generation sequencing methods have provided new opportunities for transcriptome sequencing (RNA-Seq). The unprecedented sequencing depth provided by RNA-Seq makes it a powerful and cost-efficient method for transcriptome study, and it has been widely used in model organisms and non-model organisms to identify and quantify RNA. For non-model organisms lacking well-defined genomes, de novo assembly is typically required for downstream RNA-Seq analyses, including SNP discovery and identification of genes differentially expressed by phenotypes. Although RNA-Seq has been successfully used to sequence many non-model organisms, the results of de novo assembly from short reads can still be improved by using recent bioinformatic developments.Results: In this study, we used 212.6 million pair-end reads, which accounted for 16.2 Gb, to assemble the hexaploid wheat transcriptome. Two state-of-the-art assemblers, Trinity and Trans-ABySS, which use the single and multiple k-mer methods, respectively, were used, and the whole de novo assembly process was divided into the following four steps: pre-assembly, merging different samples, removal of redundancy and scaffolding. We documented every detail of these steps and how these steps influenced assembly performance to gain insight into transcriptome assembly from short reads. After optimization, the assembled transcripts were comparable to Sanger-derived ESTs in terms of both continuity and accuracy. We also provided considerable new wheat transcript data to the community.Conclusions: It is feasible to assemble the hexaploid wheat transcriptome from short reads. Special attention should be paid to dealing with multiple samples to balance the spectrum of expression levels and redundancy. To obtain an accurate overview of RNA profiling, removal of redundancy may be crucial in de novo assembly. © 2012 Duan et al.; licensee BioMed Central Ltd.

Gao H.,China Agricultural University | Shreeve J.M.,University of Idaho
RSC Advances | Year: 2014

Synthesis, characterization, and thermolysis studies of new polynitro compounds with good oxygen balance are reported. These compounds have been fully characterized by IR, NMR, elemental analysis, differential scanning calorimetry (DSC), density, and impact sensitivity measurements. Additionally, the structure of 2,2,2-trinitro-N-2,2,2-trinitroethylidene-ethanamine (9) was confirmed by single-crystal X-ray diffraction. Based on experimental and calculated values, the properties of the new polynitro compounds, such as decomposition temperatures (102.7-154.4 °C), oxygen balance (-26.7-30.5%), detonation pressures (21.4-36.1 GPa) and velocities (7368-8749 ms-1), and impact sensitivities (3-29 J), were obtained. © 2014 the Partner Organisations.

Ma C.,University of Arizona | Ma C.,Northwest University, China | Zhang H.H.,University of Arizona | Wang X.,University of Arizona | Wang X.,China Agricultural University
Trends in Plant Science | Year: 2014

Rapid advances in high-throughput genomic technology have enabled biology to enter the era of 'Big Data' (large datasets). The plant science community not only needs to build its own Big-Data-compatible parallel computing and data management infrastructures, but also to seek novel analytical paradigms to extract information from the overwhelming amounts of data. Machine learning offers promising computational and analytical solutions for the integrative analysis of large, heterogeneous and unstructured datasets on the Big-Data scale, and is gradually gaining popularity in biology. This review introduces the basic concepts and procedures of machine-learning applications and envisages how machine learning could interface with Big Data technology to facilitate basic research and biotechnology in the plant sciences. © 2014 Elsevier Ltd.

Yuan Y.,Jilin University | Wu S.-J.,Jilin University | Liu X.,China Agricultural University | Zhang L.-L.,Jilin University
Food and Function | Year: 2013

Furan, a widely used industrial compound, has been found in many heat-treated foods, especially baby food. The presence of furan in food raises concerns about public health. In this study, we evaluated the protective effect of salidroside (SR) against furan-induced hepatocyte damage in mice livers. The in vitro antioxidant effects of SR were also evaluated. The results suggested that furan significantly increased hepatocyte damage, as proven by the increased activities of aminotransferase (AST), alanine aminotransferase (ALT) and levels of direct bilirubin (DBIL). Furan also caused oxidative stress, as evidenced by increased reactive oxygen species (ROS) production as well as malondialdehyde (MDA) levels and glutathione S-transferase (GST) activity in mice livers. Pretreatment with SR markedly attenuated the activities of AST, ALT, GST and the levels of DBIL, ROS, and MDA in a dose-dependent manner. The protective effects of SR against furan-induced hepatocyte damage were due to its excellent ability to scavenge free radicals such as 2′-azino-bis(3-ethylbenzothiazoline-6- sulphonic acid) radicals, OH, 2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl radicals and O2 -. Thus, SR exerted excellent antioxidant effects, and it may be a novel therapeutic and preventive agent for oxidative stress-related diseases. © 2013 The Royal Society of Chemistry.

Qiu L.-C.,China Agricultural University | Wu C.-Y.,University of Surrey
Journal of Hydrodynamics | Year: 2014

A hybrid scheme coupling the discrete element method (DEM) with the computational fluid dynamics (CFD) is developed to model solid-liquid flows. Instead of solving the pressure Poisson equation, we use the compressible volume-averaged continuity and momentum equations with an isothermal stiff equation of state for the liquid phase in our CFD scheme. The motion of the solid phase is obtained by using the DEM, in which the particle-particle and particle-wall interactions are modelled by using the theoretical contact mechanics. The two phases are coupled through the Newton's third law of motion. To verify the proposed method, the sedimentation of a single spherical particle is simulated in water, and the results are compared with experimental results reported in the literature. In addition, the drafting, kissing, and tumbling (DKT) phenomenon between two particles in a liquid is modelled and reasonable results are obtained. Finally, the numerical simulation of the density-driven segregation of a binary particulate suspension involving 10 000 particles in a closed container is conducted to show that the presented method is potentially powerful to simulate real particulate flows with large number of moving particles. © 2014 Publishing House for Journal of Hydrodynamics.

Zhang H.,Beijing Agricultural College | Rui Y.-K.,China Agricultural University
Journal of Saudi Chemical Society | Year: 2012

Mineral elements are essential components for human health from food, but their contents in wheat, millet, corn and soybean have not been compared. Contents of mineral elements in wheat, millet, corn and soybean from Beijing market of China were detected by ICP-MS. The RSDs (relative standard deviation) range from 0.85% to 3.52% and the detecting limits range from 0.13 to 0.85. μg/L, which showed that this method is accurate and precise to detect mineral elements in grains simultaneously. The data showed that (1) ICP-MS is a simple and precise method to determine many mineral elements in grains simultaneously. (2) Elements followed by descending order in four grains are usually K. >. Mg. >. Ca. >. Fe. >. Zn. >. Mn. >. Cu. >. Mo. >. Li, and grains arranged in order from high to low levels of mineral elements are usually soybean. >. millet. >. wheat. ≈. corn. So we should take in more minor grains, such as soybean and millet on daily diet. © 2010.

Zhang J.-F.,China Agricultural University
The Scientific World Journal | Year: 2013

The concept of L-fuzzy lattice is presented by means of an L-fuzzy partially ordered set. An L-fuzzy partially ordered set A is an L-fuzzy lattice if and only if one of A[a], A[a], and A(a) is a lattice. © 2013 Jun-Fang Zhang.

Zhang T.,CAS Institute of Atmospheric Physics | Huang Y.,CAS Institute of Botany | Yang X.,China Agricultural University
Global Change Biology | Year: 2013

An extensive dataset on rice phenology in China, including 202 series broadly covering the past three decades (1980s-2000s), was compiled. From these data, we estimated the responses of growth duration length to temperature using a regression model based on the data with and without detrending. Regression coefficients derived from the detrended data reflect only the temperature effect, whereas those derived from data without detrending represent a combined effect of temperature and confounding cultivar shifts. Results indicate that the regression coefficients calculated from the data with and without detrending show an average shortening of the growth duration of 4.1-4.4days for each additional increase in temperature over the full growth cycle. Using the detrended data, 95.0% of the data series exhibited a negative correlation between the growth duration length and temperature; this correlation was significant in 61.9% of all of the data series. We then compared the difference between the two regression coefficients calculated from data with and without detrending and found a significantly greater temperature sensitivity using the data without detrending (-2.9days°C-1) than that derived from the detrended data (-2.0 days°C-1) in the period of emergence to heading for the late rice, producing a negative difference in temperature sensitivity (-0.9days°C-1). This implies that short-duration cultivars were planted with increase in temperature and exacerbated the undesired phenological change. In contrast, positive differences were detected for the single (0.6days°C-1) and early rice (0.5days°C-1) over the full growth cycle, which might indicate that long-duration cultivars were favoured with climate warming, but these differences were insignificant. In summary, our results suggest that a major, temperature induced change in the rice growth duration is underway in China and that using a short-duration cultivar has been accelerating the process for late rice. © 2012 Blackwell Publishing Ltd.

Li P.,Peking University | Yang Y.,CAS Institute of Botany | Han W.,China Agricultural University | Fang J.,Peking University
Global Ecology and Biogeography | Year: 2014

Aim: To investigate broad-scale patterns of soil microbial nitrogen (N) and phosphorus (P) stoichiometry and their environmental drivers. Location: Global forests. Methods: By synthesizing 652 observations of soil microbial biomass N and P derived from the published literature, we investigated global patterns of soil microbial N, P and N:P ratios and their relationships with climate, soil and vegetation types. Results: Microbial N and P concentrations varied widely among forest types, with relatively low N and P concentrations but high N:P ratios in tropical forests. The N and P concentrations increased and the N:P ratio decreased with increasing latitude (or decreasing temperature). The N:P ratio showed a similar pattern along the precipitation gradient to that along the temperature gradient, whereas microbial N and P displayed weak trends along the precipitation gradient. Edaphic variables also regulated the patterns of microbial N and P stoichiometry: microbial N and P concentrations increased with soil N and P concentrations as well as with soil pH. Mixed-effects models revealed that edaphic factors explained the largest part of the variation in microbial N, P and the N:P ratio, suggesting their dominant role. Main conclusions: Our findings highlight that there are broad-scale patterns in microbial N, P and the N:P ratio along the gradients of latitude, temperature and precipitation, which are similar to those reported in plants and soils. The consistency of these patterns in plant-soil-microbe ecosystems supports the hypothesis that P is more often the major limiting element at low latitudes than at high latitudes. © 2014 John Wiley & Sons Ltd.

Borras Jr. S.M.,China Agricultural University | McMichael P.,Cornell University | Scoones I.,University of Sussex
Journal of Peasant Studies | Year: 2010

This introduction frames key questions on biofuels, land and agrarian change within agrarian political economy, political sociology and political ecology. It identifies and explains big questions that provide the starting point for the contributions to this collection. We lay out some of the emerging themes which define the politics of biofuels, land and agrarian change revolving around global (re)configurations; agro-ecological visions; conflicts, resistances and diverse outcomes; state, capital and society relations; mobilising opposition, creating alternatives; and change and continuity. An engaged agrarian political economy combined with global political economy, international relations and social movement theory provides an important framework for analysis and critique of the conditions, dynamics, contradictions, impacts and possibilities of the emerging global biofuels complex. Our hope is that this collection demonstrates the significance of a political economy of biofuels in capturing the complexity of the 'biofuels revolution' and at the same time opening up questions about its sustainability in social and environmental terms that provide pathways towards alternatives. © 2010 Taylor & Francis.

Borras S.M.,Saint Marys University, Halifax | Borras S.M.,China Agricultural University | Borras S.M.,Fellow of the Amsterdam based Transnational Institute TNI
Development and Change | Year: 2010

The transnational agrarian movements (TAMs) which have emerged in recent decades have been actively engaged in the politics and policies of international (rural) development. Intergovernmental and non-governmental development agencies have welcomed and supported TAMs in the context of promoting international 'partnerships for development'. The analysis in this article revolves around the politics of TAM representation, intermediation and mobilization around the issue of land. It focuses on La Vía Campesina in relation to three other coalitions: the International Federation of Agricultural Producers, IPC for Food Sovereignty and International Land Coalition. It is argued here that 'people linked to the land' are socially differentiated and thus have varied experiences of neoliberal globalization. Their social movements and organizations are just as differentiated, ideologically, politically and institutionally. This differentiation is internalized within and between TAMs, and partly shapes TAMs' political agendas and strategies in their interaction with international development institutions. © 2010 International Institute of Social Studies.

Zheng Z.,China Agricultural University | Henneberry S.R.,Oklahoma State University
China Economic Review | Year: 2012

The nutritional impacts of rising food prices on urban households across income classes are assessed using the 2004 NBS urban household survey data for Jiangsu province of China. Empirical results from this study suggest that the across-the-board food price increase is expected to have a substantial adverse impact on nutritional well-being of urban households and in particular, the poor. Moreover, an increase in the price of food grains alone will have the largest adverse impact on calorie and protein intakes, whereas an increase in price of oils and fats only will induce the largest reduction in fat intake. © 2012 Elsevier Inc.

Accurately estimating grassland net primary productivity (NPP) plays an important role in the study of global carbon budgeting. The six different methods (Miami Model, Schuur Model, Chikugo Model, Beijing Model, Synthetic Model and Classification Indices-based Model) were compared in terms of their performance in predicting grassland NPP with NPP derived from field-observed data at eight study sites along an altitudinal gradient in the Helan Mountain range and the surrounding desert in the Alxa Rangeland, Western Inner Mongolia, China. One hundred and twenty plot-based NPP sets from the eight study sites were used, which were obtained from 2003 to 2005, within areas classified as alpine meadow, cold temperate-humid montane meadow, cool temperate-subhumid meadow steppe, cool temperate-semiarid temperate typical steppe and cool temperate-arid temperate zonal semi-desert according to the Integrated Orderly Classification System of Grassland (IOCSG). The relative high model efficiency in predicting grassland NPP using the Classification Indices-based Model and Chikugo Model indicates that these models outperform others. On the basis of input data requirements and the number of free parameters involved in each model, the Classification Indices-based Model was found to be the best choice for the given grassland classes. The results presented in this study were not only specific to this region, but more importantly, were specific to the given grassland classes according to the IOCSG approach, which can be scaled up from plots to estimate landscape-scale effects. © 2013 Japanese Society of Grassland Science.

Chen B.,University of Houston | Chen B.,China Agricultural University | Morales R.,University of Houston | Barria M.A.,University of Houston | Soto C.,University of Houston
Nature Methods | Year: 2010

Prions, the proteinaceous infectious agent responsible for prion diseases, can be detected with high sensitivity by protein misfolding cyclic amplification (PMCA) technology. Here we describe a quantitative PMCA procedure to calculate the concentration of very low levels of prions in biological samples. Using this procedure, we determined the quantities of misfolded prion protein (PrP Sc) in brain, spleen, blood and urine of scrapie-affected hamsters. © 2010 Nature America, Inc. All rights reserved.

Chen H.,China Agricultural University | Pang T.,National University of Singapore
Bulletin of the World Health Organization | Year: 2015

The progress in genomic research has led to increased sampling and storage of biological samples in biobanks. Most biobanks are located in high-income countries, but the landscape is rapidly changing as low- and middle-income countries develop their own. When establishing a biobank in any setting, researchers have to consider a series of ethical, legal and social issues beyond those in traditional medical research. In addition, many countries may have inadequate legislative structures and governance frameworks to protect research participants and communities from unfair distribution of risks and benefits. International collaborations are frequently being created to support the establishment and proper running of biobanks in low- and middle-income countries. However, these collaborations cause cross-border issues – such as benefit sharing and data access. It is thus necessary to define and implement a fair, equitable and feasible biobank governance framework to ensure a fair balance of risks and benefits among all stakeholders. © 2014 by Institute of Fundamental Technological Research.

Ying-fen W.,China Agricultural University
Journal of Convergence Information Technology | Year: 2011

In SVM model, both training points and outputs are real numbers, that is, the measures in classification models belong to only one class. Tradition classification models cannot solve uncertain problem with fuzzy information in input and output. In this paper, we proposed a new classification method based on SVM and fuzzy optimization. So we formulate fuzzy classification problem as a fuzzy coefficient optimization. Meanwhile the optimization problem can be transformed into its γ-optimal programming. And computer algorithm is proposed also. In order to show its rationality, an example is presented. In addition, we also propose a strategy to decide the optimal threshold value in our algorithm.

Wang X.-J.,China Agricultural University
Progress in Biochemistry and Biophysics | Year: 2010

Membrane fusion between the viral envelope and host cell membrane is a key step for an enveloped virus entering into the host cell. The process involves intricate interactions between and conformational changes of viral envelope glycoproteins and corresponding cellular receptors. Herpesvirus contains many glycoproteins and different types of cellular receptors, the transformable receptor-glycoprotein complex constitutes a multipartite entry-fusion system. The molecular mechanisms of membrane fusion are generally regarded as the one of the most challenging issues in the study of enveloped virus. Much progress has been made recently in achieving a substantially improved knowledge base of this subject. A comprehensive review was presented on the structures and functions of important viral glycoproteins and receptors, formation of a receptor-glycoprotein complex during herpesvirus entry, and associated pathways. Detailed models of viral membrane fusion are also given. In addition, the prospect of future research is addressed.

Ortega D.L.,Michigan State University | Wang H.H.,Purdue University | Olynk Widmar N.J.,Purdue University | Wu L.,China Agricultural University
China Economic Review | Year: 2014

The increasing share of imported food in developed countries, such as the U.S. and European Union countries, poses new challenges for food safety and quality regulators. China as the world's biggest food producer has the fastest growing share of fish and shellfish exports to these countries. While there have been an increasing number of studies conducted on consumer demand for various food product attributes, little research has been focused on producer behavior, and studies on Chinese food producers are especially absent in the literature. The objective of this study is to assess Chinese aquaculture producers' willingness-to-change (WTC) and adopt certain production practices related to food safety. Producer preferences for enhanced food safety measures, and sustainable/eco-friendly production practices are assessed using a choice experiment. Primary data was collected in the leading aquaculture producing provinces of southern China. The average net income per farmer of our sample was 81,286. RMB/year of which approximately 72% originated from their aquaculture operation. Derived WTC estimates from a random parameters logit model suggest that the representative Chinese producer would require a 2.49% premium per jin of fish to adopt enhanced food safety practices such as those required for China GAP, and No Public Harm voluntary certifications and they would accept a 3.22% discount before being indifferent between having an antibiotic-free facility and using antibiotics. WTC estimates of sustainable eco-friendly practices and verification by various entities were also assessed. A latent class model (LCM) is used to segregate producers into group with similar underlying characteristics to develop policies to improve producer practices and ultimately product safety and quality. © 2013 Elsevier Inc.

Garg S.,University of Idaho | Gao H.,China Agricultural University | Parrish D.A.,U.S. Navy | Shreeve J.M.,University of Idaho
Inorganic Chemistry | Year: 2011

Syntheses of the first Cu(NH3)2(FOX)2 and various Cu(amine)2(FOX)2 (methyl, propyl, and dimethyl amine) complexes were achieved by using metathetical reactions which add a new chapter to the metal chemistry of FOX-7 (1,1-diamino-2,2-dintroethene). The crystal structures of Cu(NH3)2(FOX)2 and Cu(C3H7NH2)2(FOX)2 which show square planar geometry at copper aid in the understanding of the bonding modes in FOX-7 copper complexes which is supported by natural bond orbital (NBO) calculations. Water-free K-FOX was also structured. © 2010 American Chemical Society.

Gou K.-M.,University of Oxford | Gou K.-M.,China Agricultural University | Chang C.-C.,National Taiwan University | Shen Q.-J.,University of Oxford | And 3 more authors.
Experimental Cell Research | Year: 2014

CTP synthase is an essential metabolic enzyme responsible for the de novo synthesis of CTP. Multiple studies have recently showed that CTP synthase protein molecules form filamentous structures termed cytoophidia or CTP synthase filaments in the cytoplasm of eukaryotic cells, as well as in bacteria. Here we report that CTP synthase can form cytoophidia not only in the cytoplasm, but also in the nucleus of eukaryotic cells. Both glutamine deprivation and glutamine analog treatment promote formation of cytoplasmic cytoophidia (C-cytoophidia) and nuclear cytoophidia (N-cytoophidia). N-cytoophidia are generally shorter and thinner than their cytoplasmic counterparts. In mammalian cells, both CTP synthase 1 and CTP synthase 2 can form cytoophidia. Using live imaging, we have observed that both C-cytoophidia and N-cytoophidia undergo multiple rounds of fusion upon glutamine analog treatment. Our study reveals the coexistence of cytoophidia in the cytoplasm and nucleus, therefore providing a good opportunity to investigate the intracellular compartmentation of CTP synthase. © 2014.

Fu Y.,China Agricultural University
Current Opinion in Plant Biology | Year: 2015

The cytoskeleton in pollen tubes has been intensively studied, because of its abundance and prominent roles and because the pollen tube is an excellent experimental system for cell biological studies. Pollen actin microfilaments (MFs) exist as multiple distinct populations, each participating in a specific cellular trafficking or organization process. Consequently, MFs are essential for pollen tube growth and are tightly regulated in response to various signals. Pollen microtubules (MTs) are non-essential and less characterized, but recent studies have implicated MTs in vesicle trafficking and cell wall construction in pollen tubes. This review summarizes recent advances in understanding the organization and regulation of both MFs and MTs and discusses their roles in cellular trafficking and the modulation of pollen-tube tip growth. © 2015 Elsevier Ltd.

Cen S.,Tsinghua University | Fu X.-R.,China Agricultural University | Zhou M.-J.,Tsinghua University
Computer Methods in Applied Mechanics and Engineering | Year: 2011

By simply improving the first version of hybrid stress element method proposed by Pian, several 8- and 12-node plane quadrilateral elements, which are immune to severely distorted mesh containing elements with concave shapes, are successfully developed. Firstly, instead of the stresses, the stress function φ is regarded as the functional variable and introduced into the complementary energy functional. Then, the fundamental analytical solutions (in global Cartesian coordinates) of φ are taken as the trial functions for 2D finite element models, and meanwhile, the corresponding unknown stress-function constants are introduced. Thus, the resulting stress fields must be more reasonable because both the equilibrium and the compatibility relations can be satisfied. Thirdly, by using the principle of minimum complementary energy, these unknown stress-function constants can be expressed in terms of the displacements along element boundaries, which can be interpolated directly by the element nodal displacements. Finally, the complementary energy functional can be rewritten in terms of element nodal displacement vector, and thus, the element stiffness matrix of such hybrid stress-function (HS-F) element is obtained. This technique establishes a universal frame for developing reasonable hybrid stress elements based on the principle of minimum complementary energy. And the first hybrid stress element proposed by Pian is just a special case within this frame. Following above procedure, two 8-node and two 12-node quadrilateral plane elements are constructed by employing different fundamental analytical solutions of Airy stress function. Numerical results show that, the 8-node and 12-node models can produce the exact solutions for pure bending and linear bending problems, respectively, even the element shape degenerates into triangle and concave quadrangle. Furthermore, these elements do not possess any spurious zero energy mode and rotational frame dependence. © 2011 Elsevier B.V.

Durenkamp M.,Rothamsted Research | Luo Y.,China Agricultural University | Brookes P.C.,Rothamsted Research
Soil Biology and Biochemistry | Year: 2010

The efficiency of the fumigation extraction method on the determination of soil microbial biomass carbon and ninhydrin-N was tested in three different soils (UK grassland, UK arable, Chinese arable) amended with black carbon (biochar or activated charcoal). Addition of activated charcoal to soil resulted in a significant decrease in K2SO4 extractable carbon and ninhydrin-N in all three soils, whereas the addition of biochar generally did not. A lower concentration of the extraction reagent (0.05 M vs. 0.5 M K2SO4) resulted in a significantly lower extraction efficiency in the grassland soil. The extraction efficiency of organic carbon was more affected by black carbon than that of ninhydrin-N, which resulted in a decreased biomass C/ninhydrin-N ratio. The impact of black carbon on the extraction efficiency of soil microbial biomass depended on the type of black carbon, on the concentration of the extraction medium and on soil type. © 2010.

Li Y.,China Agricultural University | Li Y.,China National Institute of Biological Sciences | Zhang Q.,China National Institute of Biological Sciences | Zhang J.,China National Institute of Biological Sciences | And 3 more authors.
Plant Physiology | Year: 2010

Pathogen-associated molecular patterns (PAMPs) trigger plant defenses when perceived by surface-localized immune receptors. PAMP-triggered immunity (PTI) plays a vital role in the resistance of plants to numerous potential pathogens. MicroRNA (miRNA) biogenesis is known to be important for PTI, but miRNA species involved in this process have not been fully explored. Here we show that the Arabidopsis (Arabidopsis thaliana) miRNA effector protein, Argonaute1 (AGO1), is required for a number of PTI responses including PAMP-induced callose deposition, gene expression, and seedling growth inhibition. Deep sequencing of AGO1-bound small RNAs led to the identification of a number of miRNAs that are up- or down-regulated by flg22, a well-studied PAMP. Overexpression of selected miRNAs in stable transgenic plants demonstrated that miR160a positively regulate PAMP-induced callose deposition, whereas miR398b and miR773 negatively regulate PAMP-induced callose deposition and disease resistance to bacteria, suggesting a complexity of the miRNA regulation in plant innate immunity. © 2010 American Society of Plant Biologists.

Derpsch R.,Rolf Derpsch | Friedrich T.,Food and Agriculture Organization FAO | Kassam A.,University of Reading | Hongwen L.,China Agricultural University
International Journal of Agricultural and Biological Engineering | Year: 2010

In 1999 no-tillage farming, synonymous of zero tillage farming or conservation agriculture, was adopted on about 45 million ha world wide, growing to 72 million ha in 2003 and to 111 million ha in 2009, corresponding to an growth rate of 6 million ha per annum. Fastest adoption rates have been experienced in South America where some countries are using no-tillage farming on about 70% of the total cultivated area. Opposite to countries like the USA where often fields under no-tillage farming are tilled every now and then, more than two thirds of the area under no-tillage systems in South America is permanently not tilled; in other words once adopted, the soil is never tilled again. The spread of no-tillage systems on more than 110 million ha world-wide shows the great adaptability of the systems to all kinds of climates, soils and cropping conditions. No-tillage is now being practiced from the artic circle over the tropics to about 50olatitude south, from sea level to 3,000 m altitude, from extremely rainy areas with 2,500 mm a year to extremely dry conditions with 250 mm a year. No-till farming offers a way of optimizing productivity and ecosystem services, offering a wide range of economic, environmental and social benefits to the producer and to the society. At the same time, no-till farming is enabling agriculture to respond to some of the global challenges associated with climate change, land and environmental degradation, and increasing cost of food, energy and production inputs. The wide recognition of no-till farming as a truly sustainable system should ensure the spread of the no-till technology and the associated practices of organic soil cover and crop rotation, as soon as the barriers to its adoption have been overcome, to areas where adoption is currently still low. The widespread adoption globally also shows that no-tillage farming cannot any more be considered a temporary fashion or a craze; instead largely through farmers'own effort, the system has established itself as a farming practice and a different way of thinking about sustainable agro-ecosystem management that can no longer be ignored by scientists, academics, extension workers, farmers at large as well as equipment and machine manufacturers and politicians.

Xu Y.,University of Science and Technology Beijing | Xu Y.,Gordon Life Science Institute | Wen X.,University of Science and Technology Beijing | Shao X.-J.,Binzhou University | And 3 more authors.
International Journal of Molecular Sciences | Year: 2014

Post-translational modifications (PTMs) play crucial roles in various cell functions and biological processes. Protein hydroxylation is one type of PTM that usually occurs at the sites of proline and lysine. Given an uncharacterized protein sequence, which site of its Pro (or Lys) can be hydroxylated and which site cannot? This is a challenging problem, not only for in-depth understanding of the hydroxylation mechanism, but also for drug development, because protein hydroxylation is closely relevant to major diseases, such as stomach and lung cancers. With the avalanche of protein sequences generated in the post-genomic age, it is highly desired to develop computational methods to address this problem. In view of this, a new predictor called "iHyd-PseAAC" (identify hydroxylation by pseudo amino acid composition) was proposed by incorporating the dipeptide position-specific propensity into the general form of pseudo amino acid composition. It was demonstrated by rigorous cross-validation tests on stringent benchmark datasets that the new predictor is quite promising and may become a useful high throughput tool in this area. A user-friendly web-server for iHyd-PseAAC is accessible at http://app.aporc.org/iHyd-PseAAC/. Furthermore, for the convenience of the majority of experimental scientists, a step-by-step guide on how to use the web-server is given. Users can easily obtain their desired results by following these steps without the need of understanding the complicated mathematical equations presented in this paper just for its integrity. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

Tao G.,Swedish University of Agricultural Sciences | Tao G.,China Agricultural University | Geladi P.,Swedish University of Agricultural Sciences | Lestander T.A.,Swedish University of Agricultural Sciences | Xiong S.,Swedish University of Agricultural Sciences
Renewable and Sustainable Energy Reviews | Year: 2012

A study was carried out based on ash composition data (relative proportion of SiO 2, K 2O, CaO, MgO, Na 2O, P 2O 5, Al 2O 3, Fe 2O 3 and SO 2 in ash) in a large number of biomass species and assortments. The data were collected from 109 peer-reviewed publications and consisted of 367 objects for ash composition analysis. Principal component analysis (PCA) was used to analyze the data. The analyses were performed at five levels of plant classifications respectively: level 1-3 for life-forms/species groups, level 4 for assortments and level 5 for species. Woody species data points tended to differ from herbaceous ones in terms of PCA for level 1 analysis. The loading plot of the two first components (PC1 and PC2) indicated that the woody species tended to be associated with Ca-Mg-P-K-S, while the herbaceous ones were closer to Si. Ca and Si had the largest contributions in forming the pattern. The woody group had a larger variation than the herbaceous group in terms of ash composition but this could be explained only by differentiation in assortments as illustrated with the level 4 analysis. The PCA analyses at levels 2 and 3 did not generate significant patterns, as the variations within the groups were larger than between the groups. The variation of the herbaceous data, however, could be explained by all level 2-5 analyses and attributed to differences between herbaceous dicots and graminoids, between C3 and C4 plants, and between assortments such as husk, fruit residues and bagasse. The robust analysis had in general the same results. These results could be further interpreted by the trend that Si decreased but Ca increased gradually in the following order: C3 graminoids → C4 graminoids → herbaceous dicots → woody groups. It was also found that K, P, Mg and S were higher in herbaceous dicots than in graminoids. © 2012 Elsevier Ltd. All rights reserved.

Longin C.F.H.,University of Hohenheim | Muhleisen J.,University of Hohenheim | Maurer H.P.,University of Hohenheim | Zhang H.,China Agricultural University | And 2 more authors.
Theoretical and Applied Genetics | Year: 2012

Hybrid breeding in autogamous cereals has a long history of attempts with moderate success. There is a vast amount of literature investigating the potential problems and solutions, but until now, market share of hybrids is still a niche compared to line varieties. Our aim was to summarize the status quo of hybrid breeding efforts for the autogamous cereals wheat, rice, barley, and triticale. Furthermore, the research needs for a successful hybrid breeding in autogamous cereals are intensively discussed. To our opinion, the basic requirements for a successful hybrid breeding in autogamous cereals are fulfilled. Nevertheless, optimization of the existing hybridization systems is urgently required and should be coupled with the development of clear male and female pool concepts. We present a quantitative genetic framework as a first step to compare selection gain of hybrid versus line breeding. The lack of precise empirical estimates of relevant quantitative genetic parameters, however, is currently the major bottleneck for a robust evaluation of the potential of hybrid breeding in autogamous cereals. © 2012 Springer-Verlag.

Zhao J.H.,China Agricultural University | Ho P.,Leiden University | Azadi H.,Leiden University
Environmental Monitoring and Assessment | Year: 2011

In the past, scientific research has predicted a decrease in the effectiveness of Bt cotton due to the rise of secondary and other sucking pests. It is suspected that once the primary pest is brought under control, secondary pests have a chance to emerge due to the lower pesticide applications in Bt cotton cultivars. Studies on this phenomenon are scarce. This article furnishes empirical evidence that farmers in China perceive a substantial increase in secondary pests after the introduction of Bt cotton. The research is based on a survey of 1,000 randomly selected farm households in five provinces in China. We found that the reduction in pesticide use in Bt cotton cultivars is significantly lower than that reported in research elsewhere. This is consistent with the hypothesis suggested by recent studies that more pesticide sprayings are needed over time to control emerging secondary pests, such as aphids, spider mites, and lygus bugs. Apart from farmers' perceptions of secondary pests, we also assessed their basic knowledge of Bt cotton and their perceptions of Bt cotton in terms of its strengths and shortcomings (e.g.; effectiveness, productivity, price, and pesticide use) in comparison with non-transgenic cotton. © 2010 The Author(s).

Meng X.,Zhejiang University of Technology | Pan Q.,China Agricultural University | Ding Y.,Zhejiang University of Technology | Jiang L.,Northeast Agricultural University
Food Chemistry | Year: 2014

A rapid mid-FTIR method was developed to quantitatively determine the total phospholipid (PL) content of vegetable oils. The method simply requires that the oil be diluted 4:1 (w/w) with hexane, its spectrum taken and ratioed against a hexane background. A calibration was devised using partial least squares by adding purified soybean PL at levels of 0.02-2.0% to phospholipid-free oils (soybean, rapeseed, sunflower) using the spectral region encompassing 1357-1000 cm-1 and validated using the AOCS 12-55. Using calibration and leave-one-out cross-validation predictive errors, a 200-20,000 ppm calibration was accurate to within ±362 and 488 ppm, respectively, while for sub-calibrations ranging from 200 to 2000; 2000 to 8000 and 8000 to 20,000 ppm, they were ±72-172, ±119-220, and ± 242-371 ppm, respectively. Although limited to 3 oil types in this study, the calibration is simple to devise and can be broadened to the universe of oil types of interest, the analytical protocol being straightforward and the analysis readily automatable. © 2013 Elsevier Inc. All rights reserved.

Gao Z.,Agricultural University of Hebei | Yuan H.,Agricultural University of Hebei | Ma W.,Agricultural University of Hebei | Liu X.,China Agricultural University | Desjardins R.L.,Agriculture and Agri Food Canada
Environmental Pollution | Year: 2011

Accurately determining methane emission factors of dairy herd in China is imperative because of China's large population of dairy cattle. An inverse dispersion technique in conjunction with open-path lasers was used to quantify methane emissions from a dairy feedlot during the fall and winter seasons in 2009-2010. The methane emissions had a significant diurnal pattern during both periods with three emission peaks corresponding to the feeding schedule. A 10% greater emission rate in the fall season was obtained most likely by the higher methane emission from manure during that period. An annual methane emission rate of 109 ± 6.7 kg CH4 yr-1 characterized with a methane emission intensity of 32.3 ± 1.59 L CH4 L-1 of milk and a methane conversion factor (Ym) of 7.3 ± 0.38% for mature cattle was obtained, indicating the high methane emission intensity and low milk productivity in Northern China. © 2011 Elsevier Ltd. All rights reserved.

Gao H.,China Agricultural University | Shreeve J.M.,University of Idaho
Chemical Reviews | Year: 2011

An energetic material is a compound or a mixture of compounds that, when subjected controllably to friction, impact, spark, or shock, undergoes rapid, heat-producing decomposition. Modification of azoles with either a mono- or multifunctional energy group builds molecules which may be transformed into salts through neutralization or quaterization reactions combined with subsequent metathesis. The enthalpies of formation of azoles are dependent on their ring structures. They can be adjusted by substitution of the hydrogen atoms with various energetic functional groups. Tetrazoles are an important core of energetic materials because of the practical and theoretical significance of these unique compounds and the diversity of their properties. Most tetrazolate salts are highly endothermic compounds. The reaction of 5-Nitroimino-tetrazoles which are five-membered aromatic heterocycles with a nitroimine functional group, with heterocyclic bases yield 5-nitroimino-1H-tetrazolate monohydrate salts.

Wang W.,Heilongjiang Bayi Agricultural University | Yan L.,Heilongjiang Bayi Agricultural University | Cui Z.,China Agricultural University | Gao Y.,Heilongjiang Bayi Agricultural University | And 2 more authors.
Bioresource Technology | Year: 2011

A microbial consortium, designated WCS-6, was established by successive subcultivation in the presence of rice straw under static conditions. The degradation efficiencies of WSC-6 for 0.5. g filter paper, cotton and rice straw after 3. days of cultivation were 99.0 ± 0.7%, 76.9 ± 1.5% and 81.3 ± 0.8%, respectively as determined by gravimetrical methods. Nine bacterial isolates were obtained from WCS-6 plated under aerobic conditions, and sequencing of their 16S rDNA indicated that these bacteria were related to Bacillus thermoamylovorans BTa, Paenibacillus barengoltzii SAFN-016, Proteobacterium S072, Pseudoxanthomonas taiwanensis CB-226, Rhizobiaceae str. M100, Bacillus sp. E53-10, Beta proteobacterium HMD444, Petrobacter succinimandens 4BON, and Tepidiphilus margaritifer N2-214. DGGE (denaturing gradient gel electrophoresis) and sequencing of 16S rDNA sequences amplified from total consortium DNA revealed the presence of sequences related to those of Ureibacillus thermosphaericus, uncultured bacterium clone GC3, uncultured Clostridium sp. clone A1-3, Clostridium thermobutyricum, and Clostridium thermosuccinogenes in addition to the sequences identified from the cultured bacteria. The microbial community identified herein is a potential candidate consortium for the degradation of waste lignocellulosic biomass. © 2011 Elsevier Ltd.

Song Y.,Nanjing Agricultural University | Shumin Z.,China Agricultural University
International Journal of Agricultural and Biological Engineering | Year: 2015

In order to optimize the structure schema of flexible comb-type grass seeder, the effects of combing teeth gap L, rotation speed of comb shaft N, seed metering device inclining angle α and groove strip inclining angle θ on the rate and uniformity of seeding were observed by test and analyzed, then the coefficient of seeding stability variation was explored in the simulating planting environment on the soil tank test bed based on the above four influencing factors, with Festuca arundinacea seeds as example. According to the results of regression analysis, the model fits well with the actual situation. L, N, α, and the interaction term of N and θ are significant, and the interaction term of θ and α is extremely significant. The analysis of interaction factor effect shows that the variation coefficient responds to the interaction of N and θ in the same manner as that responds to the interaction of θ and α, showing ‘saddle’ variation tendency. Suppose the acceptable maximum value of coefficient of seeding uniformity variation is 4%, then the inverse proportion relationship between factors is inferred according to the change trend of the above interaction factors and derivation of regression equation. Then the regression equation was simplified according to the inverse proportion equation, and four groups of parameters were obtained. Each parameter group was tested, and the test results agreed with the regression equation’s predicting value, with the correlation coefficient 0.726. This research can provide reference for the development of seed metering devices and grass seeders. © 2014 Chinese Society of Agricultural Engineering. All Rights reserved.

Li S.,China Agricultural University
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2016

The degree of freedom (DOF) is a significant index to reflect the moving capability of flexure mechanisms. Since the complexity and deficiency for analyzing the DOF of flexure mechanisms, two methods for analyzing the DOF of flexure mechanisms are presented. First one is a visualized method to analyze the DOF through mapping, based on the former research on graphic method, this method is simple and straight to be understood; the other method is based on the comparison of the normalized eigen-compliances of compliance matrix to analyze the DOF of flexure mechanisms. After the detailed analyzing on parallelogram flexure module, cartwheel flexure module, and the combination of these two modules, the derived two methods are certified their validity and practicability. © 2016 Journal of Mechanical Engineering.

Shock C.C.,Oregon State University | Wang F.-X.,China Agricultural University
HortScience | Year: 2011

A fundamental way to schedule irrigation is through the monitoring and management of soil water tension (SWT). Soil water tension is the force necessary for plant roots to extract water from the soil. With the invention of tensiometers, SWT measurements have been used to schedule irrigation. There are different types of field instruments used to measure SWT, either directly or indirectly. Precise irrigation scheduling by SWT criteria is a powerful method to optimize plant performance. Specific SWT criteria for irrigation scheduling have been developed to optimize the production and quality of vegetable crops, field crops, trees, shrubs, and nursery crops. This review discusses known SWT criteria for irrigation scheduling that vary from 2 to 800 kPa depending on the crop species, plant product to be optimized, environmental conditions, and irrigation system. By using the ideal SWT and adjusting irrigation duration and amount, it is possible to simultaneously achieve high productivity and meet environmental stewardship goals for water use and reduced leaching.

Ye L.,China Agricultural University | Lin L.Z.,CAS Institute of Electrical Engineering
IEEE Transactions on Applied Superconductivity | Year: 2010

As electrical energy will be provided from renewable sources, the connection of a large number of wind farms to existing distribution networks may lead to the increasing fault levels beyond the capacity of existing switchgear, especially in urban areas. Fault current limiters (FCLs) are essentially expected to control the prospective short circuit currents. In this paper, investigations were carried out to assess the effectiveness of the resistive superconducting fault current limiters (SFCLs) for fault level management in wind power system. System studies confirmed that the superconducting fault current limiter (SFCL) could not only control the fault currents but also suppress the inrush currents, when wind farm has adopted in the case of the system interconnection. As a result, the highly efficient operation of the wind power system becomes more possible by introducing the superconducting fault current limiters. © 2006 IEEE.

Shao Y.-H.,Zhejiang University of Technology | Deng N.-Y.,China Agricultural University | Yang Z.-M.,Zhejiang University of Technology
Pattern Recognition | Year: 2012

In this paper we formulate a least squares version of the recently proposed projection twin support vector machine (PTSVM) for binary classification. This formulation leads to extremely simple and fast algorithm, called least squares projection twin support vector machine (LSPTSVM) for generating binary classifiers. Different from PTSVM, we add a regularization term, ensuring the optimization problems in our LSPTSVM are positive definite and resulting better generalization ability. Instead of usually solving two dual problems, we solve two modified primal problems by solving two systems of linear equations whereas PTSVM need to solve two quadratic programming problems along with two systems of linear equations. Our experiments on publicly available datasets indicate that our LSPTSVM has comparable classification accuracy to that of PTSVM but with remarkably less computational time. © 2011 Elsevier Ltd. All rights reserved.

Jiang C.,China Agricultural University | Jiang C.,University of Oxford | Mithani A.,Lahore University of Management Sciences | Belfield E.J.,University of Oxford | And 3 more authors.
Genome Research | Year: 2014

Evolution is fueled by phenotypic diversity, which is in turn due to underlying heritable genetic (and potentially epigenetic) variation. While environmental factors are well known to influence the accumulation of novel variation in microorganisms and human cancer cells, the extent to which the natural environment influences the accumulation of novel variation in plants is relatively unknown. Here we use whole-genome and whole-methylome sequencing to test if a specific environmental stress (high-salinity soil) changes the frequency and molecular profile of accumulated mutations and epimutations (changes in cytosine methylation status) in mutation accumulation (MA) lineages of Arabidopsis thaliana. We first show that stressed lineages accumulate ∼100% more mutations, and that these mutations exhibit a distinctive molecular mutational spectrum (specific increases in relative frequency of transversion and insertion/deletion [indel] mutations). We next show that stressed lineages accumulate ∼45% more differentially methylated cytosine positions (DMPs) at CG sites (CG-DMPs) than controls, and also show that while many (∼75%) of these CG-DMPs are inherited, some can be lost in subsequent generations. Finally, we show that stress-associated CG-DMPs arise more frequently in genic than in nongenic regions of the genome. We suggest that commonly encountered natural environmental stresses can accelerate the accumulation and change the profiles of novel inherited variants in plants. Our findings are significant because stress exposure is common among plants in the wild, and they suggest that environmental factors may significantly alter the rates and patterns of incidence of the inherited novel variants that fuel plant evolution. © 2014 Jiang et al.

Wang F.,China Agricultural University
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2016

Rotating turbulent flows are widely existed in pumps, turbines, compressors and other fluid machinery. The three-dimensional stochastic fluctuations are very strong in this kind of flow. The high adverse pressure gradient, large streamline curvature and complex wall surface in rotating turbulent flow have significant effects on the performance of fluid machinery. Although a lot of turbulence models have been developed, there is no universal turbulence model that could be used to simulate rotating turbulent flow in fluid machinery. Each turbulence model has its own applicable scope. The prediction performance of the existing turbulence models either in physical or numerical aspects has not yet met the actual need of fluid machinery. Aiming at strong rotating and large curvature turbulent flow, the turbulence models were reviewed. From three aspects of the high Reynolds number flow in turbulent core area, the low Reynolds number flow near wall and the transition flow from laminar to turbulent areas, the applicability of existing turbulence models for fluid machinery was analyzed. The problems of two series turbulence models, including Reynolds-averaged Navier-Stokes models and scale-resolving simulation models used in solving rotating turbulent flow were compared. The typical Reynolds-averaged Navier-Stokes models introduced included Spalart-Allmaras, k-ε, k-ω, V2F and RSM models. The typical scale-resolving simulation models included LES, SAS, DES and ELES models. The effective methods to use the suitable turbulence model for different problems and different targets were investigated. The development trend of turbulence model and the application of turbulence model in fluid machinery were discussed. © 2016, Chinese Society of Agricultural Machinery. All right reserved.

Chang F.,Fudan University | Chang F.,China Agricultural University | Chang F.,University of California at Riverside | Gu Y.,University of California at Riverside | And 3 more authors.
Molecular Plant | Year: 2013

The ROP1 GTPase-based signaling network controls tip growth in Arabidopsis pollen tubes. Our previous studies imply that ROP1 might be directly activated by RopGEF1, which belongs to a plant-specific family of Rho guanine nucleotide exchange factors (RopGEFs) and in turn may be activated by an unknown factor through releasing RopGEF1's auto-inhibition. In this study, we found that RopGEF1 forms a complex with ROP1 and AtPRK2, a receptor-like protein kinase previously shown to interact with RopGEFs. AtPRK2 phosphorylated RopGEF1 in vitro and the atprk1,2,5 triple mutant showed defective pollen tube growth, similar to the phenotype of the ropgef1,9,12,14 quadruple mutant. Overexpression of a dominant negative form of AtPRK2 (DN-PRK2) inhibited pollen germination in Arabidopsis and reduced pollen elongation in tobacco. The DN-PRK2-induced pollen germination defect was rescued by overexpressing a constitutively active form of RopGEF1, RopGEF1(90'457), implying that RopGEF1 acts downstream of AtPRK2. Moreover, AtPRK2 increased ROP1 activity at the apical plasma membrane whereas DN-PRK2 reduced ROP1 activity. Finally, two mutations at the C-terminal putative phosphorylation sites of RopGEF1 (RopGEF1S460A and RopGEF1S480A) eliminated the function of RopGEF1 in vivo. Taken together, our results support the hypothesis that AtPRK2 acts as a positive regulator of the ROP1 signaling pathway most likely by activating RopGEF1 through phosphorylation. © 2013 The Author.

Yong Y.-C.,Nanyang Technological University | Yong Y.-C.,China Agricultural University | Dong X.-C.,Nanjing University of Posts and Telecommunications | Chan-Park M.B.,Nanyang Technological University | And 2 more authors.
ACS Nano | Year: 2012

Microbial fuel cell (MFC) is of great interest as a promising green energy source to harvest electricity from various organic matters. However, low bacterial loading capacity and low extracellular electron transfer efficiency between the bacteria and the anode often limit the practical applications of MFC. In this work, a macroporous and monolithic MFC anode based on polyaniline hybridized three-dimensional (3D) graphene is demonstrated. It outperforms the planar carbon electrode because of its abilities to three-dimensionally interface with bacterial biofilm, facilitate electron transfer, and provide multiplexed and highly conductive pathways. This study adds a new dimension to the MFC anode design as well as to the emerging graphene applications. © 2012 American Chemical Society.

Shao Y.-H.,Zhejiang University of Technology | Deng N.-Y.,China Agricultural University
Neural Computing and Applications | Year: 2013

For classification problems, twin support vector machine (TWSVM) determines two nonparallel hyperplanes by solving two related SVM-type problems. TWSVM classifies binary patterns by the proximity of it to one of the two nonparallel hyperplanes. Thus, to calculate the distance of a pattern from the hyperplane, we need the unity norm of the normal vector of the hyperplane. But in the formulation of TWSVM, these equality constraints were not considered. In this paper, we consider unity norm constraints by using Euclidean norm and add a regularization term with the idea of maximizing some margin in TWSVM and propose a novel margin-based twin support vector machines with unity norm hyperplanes (UNH-MTSVM). We solved UNH-MTSVM by Newton's method, and the solution is updated by conjugate gradient method. The performance of both the linear and nonlinear UNH-MTSVM is verified experimentally on several bench mark and synthetic datasets. Experimental results show the effectiveness of our methods in both computation time and classification accuracy. © 2012 Springer-Verlag London Limited.

Meng L.,China National Institute of Biological Sciences | Meng L.,China Agricultural University | Jin W.,Tsinghua University | Wang X.,China National Institute of Biological Sciences
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

Systematic inflammation contributes to the development of many diseases, including cardiovascular disease, which is the leading cause of mortality worldwide. How such inflammation is initiated and maintained throughout the course of disease remains unclear. In the current study, we report the observation of specific phosphorylation of the receptor-interacting protein 3 (RIP3) kinase that marks the activation of programmed necrosis (also called the "necroptosis pathway") in the atherosclerotic plaques in apolipoprotein E (ApoE)-knockout mice. The mRNA expression levels of 10 inflammatory cytokines, including IL-1α, were decreased significantly in the plaque regions of mice lacking RIP3. Lymphocyte infiltrations in the adipocyte tissue and in skin lesions of ApoE single-knockout mice were significantly mitigated in ApoE/RIP3 double-knockout mice. The high percentage of inflammatory monocytes with high levels of lymphocyte antigen 6C in the blood of ApoE single-knockout mice also was greatly decreased in the ApoE/RIP3 double-knockout mice. Most significantly, the double-knockout mice displayed dramatically delayed mortality compared with ApoE single-knockout mice. Our findings indicate that necrotic death in areas such as atherosclerotic plaques may release cytokines that mobilize monocytes from bone marrow to the lesion sites, exacerbating the lesions in multiple tissues and resulting in the premature death of the animals. © 2015, National Academy of Sciences. All rights reserved.

Yu Z.,China Agricultural University
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2011

The ecological and landscaping strategy and technologies of rural land consolidation in China were discussed aiming at providing solutions to the problems in China's rural land use and meeting the demands in rural landscape enhancement. The present land use problems in the rural area of China and the development of modern land consolidation were reviewed and the strategies, approaches and technical demands related to rural land consolidation were proposed. The landscape character should be assessed for the conservation and enhancement of the cultural and aesthetic value of rural landscape. Study on multifunctional land use should be strengthened to enhance the ecological services and landscape values, mainly including the construction of ecological network and green infrastructure in large scale, the enhancement and creation of the habitat and landscape quality in small scale. The eco-hydraulogical process of watershed should be studied for the control of non-point pollutions, mitigation and adaptation of climate change. The ecological and landscape engineering need to be studied for the improvement of land consolidation guideline, as well as the updating of land consolidation stewardship for the increase of the public participation.

Cao S.,Beijing Forestry University | Chen L.,CAS Institute of Soil and Water Conservation | Shankman D.,University of Alabama | Wang C.,Beijing Forestry University | And 2 more authors.
Earth-Science Reviews | Year: 2011

Afforestation is a primary tool for controlling desertification and soil erosion in China. Large-scale afforestation, however, has complex and poorly understood consequences for the structure and composition of future ecosystems. Here, we discuss the potential links between China's historical large-scale afforestation practices and the program's effects on environmental restoration in arid and semi-arid regions in northern China based on a review of data from published papers, and offer recommendations to overcome the shortcomings of current environmental policy. Although afforestation is potentially an important approach for environmental restoration, current Chinese policy has not been tailored to local environmental conditions, leading to the use of inappropriate species and an overemphasis on tree and shrub planting, thereby compromising the ability to achieve environmental policy goals. China's huge investment to increase forest cover seems likely to exacerbate environmental degradation in environmentally fragile areas because it has ignored climate, pedological, hydrological, and landscape factors that would make a site unsuitable for afforestation. This has, in many cases, led to the deterioration of soil ecosystems and decreased vegetation cover, and has exacerbated water shortages. Large-scale and long-term research is urgently needed to provide information that supports a more effective and flexible environmental restoration policy. © 2010 Elsevier B.V.

Gu J.,Wageningen University | Yin X.,Wageningen University | Stomph T.-J.,Wageningen University | Wang H.,China Agricultural University | Struik P.C.,Wageningen University
Journal of Experimental Botany | Year: 2012

To understand the physiological basis of genetic variation and resulting quantitative trait loci (QTLs) for photosynthesis in a rice (Oryza sativa L.) introgression line population, 13 lines were studied under drought and well-watered conditions, at flowering and grain filling. Simultaneous gas exchange and chlorophyll fluorescence measurements were conducted at various levels of incident irradiance and ambient CO2 to estimate parameters of a model that dissects photosynthesis into stomatal conductance (gs), mesophyll conductance (gm), electron transport capacity (Jmax), and Rubisco carboxylation capacity (Vcmax). Significant genetic variation in these parameters was found, although drought and leaf age accounted for larger proportions of the total variation. Genetic variation in light-saturated photosynthesis and transpiration efficiency (TE) were mainly associated with variation in gs and gm. One previously mapped major QTL of photosynthesis was associated with variation in gs and gm, but also in Jmax and Vcmax at flowering. Thus, gs and gm, which were demonstrated in the literature to be responsible for environmental variation in photosynthesis, were found also to be associated with genetic variation in photosynthesis. Furthermore, relationships between these parameters and leaf nitrogen or dry matter per unit area, which were previously found across environmental treatments, were shown to be valid for variation across genotypes. Finally, the extent to which photosynthesis rate and TE can be improved was evaluated. Virtual ideotypes were estimated to have 17.0% higher photosynthesis and 25.1% higher TE compared with the best genotype investigated. This analysis using introgression lines highlights possibilities of improving both photosynthesis and TE within the same genetic background. © [2012] The Author.

Feng Z.,CAS Research Center for Eco Environmental Sciences | Hu E.,CAS Research Center for Eco Environmental Sciences | Wang X.,CAS Research Center for Eco Environmental Sciences | Jiang L.,CAS Research Center for Eco Environmental Sciences | Liu X.,China Agricultural University
Environmental Pollution | Year: 2015

Ground-level ozone (O3) pollution has become one of the top environmental issues in China, especially in those economically vibrant and densely populated regions. In this paper, we reviewed studies on the O3 concentration observation and O3 effects on food crops throughout China. Data from 118 O3 monitoring sites reported in the literature show that the variability of O3 concentration is a function of geographic location. The impacts of O3 on food crops (wheat and rice) were studied at five sites, equipped with Open Top Chamber or O3-FACE (free-air O3 concentration enrichment) system. Based on exposure concentration and stomatal O3 flux-response relationships obtained from the O3-FACE experimental results in China, we found that throughout China current and future O3 levels induce wheat yield loss by 6.4-14.9% and 14.8-23.0% respectively. Some policies to reduce ozone pollution and impacts are suggested. © 2015 Elsevier Ltd. All rights reserved.

Zhang Y.,University of Idaho | Gao H.,China Agricultural University | Joo Y.-H.,Hanwha Corporation | Shreeve J.M.,University of Idaho
Angewandte Chemie - International Edition | Year: 2011

In propellant systems, fuels of choice continue to be hydrazine and its derivatives, even though they comprise a class of acutely carcinogenic and toxic substances which exhibit rather high vapor pressures and require expensive handling procedures and costly safety precautions. Only recently (2008), ionic liquids (salts with melting points less than 100 °C) with the dicyanamide anion were shown to exhibit hypergolic properties (instantaneous ignition when contacted with oxidizers (100 % nitric acid, WFNA)). Such liquids tend to have low volatilities, and high thermal and chemical stabilities, and often exhibit long liquid ranges which could allow utilization of these substances as bipropellant fuels over a variety of conditions. A new family of dicyanoborates is presented, which can be synthesized in water, with substituted N-acyclic, N-cyclic, and azolium cations has met nearly all of the desired important criteria needed for well-performing fuels. Ignite my fire: Design and synthesis of ionic-liquid-based energetic materials provides a powerful methodology in the development of a new type of hypergolic fuel (one that undergoes instantaneous ignition on contact with oxidizers). A new family of dicyanoborate ionic liquids is presented (see picture), which are synthesizable in water, and has met nearly all of the desired important criteria for well performing fuels. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hairong Y.,Hong Kong Polytechnic University | Yiyuan C.,China Agricultural University | Bun K.H.,Hong Kong Polytechnic University
Journal of Peasant Studies | Year: 2016

Lester Brown sounded an alarm in 1995: who will feed China? Against this backdrop, this contribution examines China's dramatic turn from having been a soybean net exporter, up until the mid-1990s, to being the biggest importer of genetically modified (GM) soybeans, since 2000. With China's growing soybean imports, domestic soybean production has experienced a drastic fall, creating an outcry about a ‘soybean crisis’ in China. This paper examines competing interpretations about China's soybean imports and how a wide arrange of heated debates and critical reflections have emerged about China's position in globalization, the role of the state in food security, the safety of GM foods, consumer rights, what constitutes scientific authority, and the power of transnational corporations. In these debates, Chinese critics have very different views about the US and South America, where significant GM soybeans are produced for export to China. © 2016 Taylor & Francis.

Chen M.-H.,China Agricultural University | Fang H.-W.,Tsinghua University | Huang L.,Tsinghua University
Ocean Dynamics | Year: 2013

Surface charge distribution has great impact on interactions between sediment particles, which is essential for flocculation studies. In this paper, the micro-morphology and surface charge distribution of quartz sand are measured using the electrical force microscope. Then, the statistical relationship between micro-morphology and surface charge distribution is obtained. Results show that quartz sand possesses a complex surface morphology, which has great impact on the charge distribution. Positive and negative charges mostly concentrate in the saddle, convex, and concave parts of the surface, while their distribution is less in the groove, ridge, and flat parts. A fitting equation between surface charge and non-spherical curvature is also obtained. The surface charge distribution on a mathematical sediment particle is then reproduced according to these relations, and the effect of charge heterogeneity on interactions between different particles is quantified and analyzed, indicating that surface charge distribution has a dramatic effect on interactions between sediment particles, and local surface potential is more important than the average surface potential. This study provides a new method for understanding the processes of flocculation in coastal and estuarine zones. © 2013 Springer-Verlag Berlin Heidelberg.

Ding Y.,Huazhong Agricultural University | Wang S.,China Agricultural University
Nongye Jixie Xuebao/Transactions of the Chinese Society of Agricultural Machinery | Year: 2010

The vision navigation control hardware system was set up in the combine harvester and a histogram fusion algorithm for multi-frame navigation lines was put forward. On the basis of kinematics of simplified two-wheel vehicle, model one fuzzy PD controller was constructed. The tests in wheat field show that the rotation and projection algorithm with histogram fusion algorithm is valid to recognize the cut/uncut line, and can improve the precision of the system and robustness, the change of harvesting width is in 0.18 m during the working speed, and it could come back to the right path in 2-5 s when given manual disturbance using steering wheel.

Duan Y.E.,China Agricultural University
Journal of Software | Year: 2011

In recent years, accidents in food quality & safety frequently occur, and more and more people have begun to think highly of food quality & safety and encourage food producers to be able to trace the origin of ingredients and process of production along the supply chain. With the development of IT, more and more practices have shown that the supply chain of agricultural products should rely on IT. The using of IT directly decides the degree of agricultural informatization and efficiency of agricultural supply chain management. In this paper, on the basis of introducing the meanings and characteristics of supply chain management and agricultural supply chain management, it also analyzes the information flow's attributes throughout the process of agricultural supply and the technological attributes of Internet of Things, finally, the designing method and architecture of integrated information platform of agricultural supply chain management based on internet of things was discussed in detail. © 2011 ACADEMY PUBLISHER.

Guo P.,China Agricultural University | Huang G.H.,University of Regina | Huang G.H.,Peking University | Li Y.P.,Peking University
Advances in Water Resources | Year: 2010

In this study, an inexact fuzzy-chance-constrained two-stage mixed-integer linear programming (IFCTIP) approach is developed for flood diversion planning under multiple uncertainties. A concept of the distribution with fuzzy boundary interval probability is defined to address multiple uncertainties expressed as integration of intervals, fuzzy sets and probability distributions. IFCTIP integrates the inexact programming, two-stage stochastic programming, integer programming and fuzzy-stochastic programming within a general optimization framework. IFCTIP incorporates the pre-regulated water-diversion policies directly into its optimization process to analyze various policy scenarios; each scenario has different economic penalty when the promised targets are violated. More importantly, it can facilitate dynamic programming for decisions of capacity-expansion planning under fuzzy-stochastic conditions. IFCTIP is applied to a flood management system. Solutions from IFCTIP provide desired flood diversion plans with a minimized system cost and a maximized safety level. The results indicate that reasonable solutions are generated for objective function values and decision variables, thus a number of decision alternatives can be generated under different levels of flood flows. © 2009 Elsevier Ltd. All rights reserved.

Shao Y.-H.,Zhejiang University of Technology | Wang Z.,Jilin University | Chen W.-J.,Zhejiang University of Technology | Deng N.-Y.,China Agricultural University
Knowledge-Based Systems | Year: 2013

For the recently proposed projection twin support vector machine (PTSVM) [1], we propose a simpler and reasonable variant from theoretical point of view, called projection twin support vector machine with regularization term, RPTSVM for short. Note that only the empirical risk minimization is introduced in primal problems of PTSVM, incurring the possible singularity problems. Our RPTSVM reformulates the primal problems by adding a maximum margin regularization term, and, therefore, the singularity is avoided and the regularized risk principle is implemented. In addition, the nonlinear classification ignored in PTSVM is also considered in our RPTSVM. Further, a successive overrelaxation technique and a genetic algorithm are introduced to solve our optimization problems and to do the parameter selection, respectively. Computational comparisons of our RPTSVM against original PTSVM, TWSVM and MVSVM indicate that our RPTSVM obtains better generalization than others. © 2012 Elsevier B.V. All rights reserved.

Shao Y.-H.,Zhejiang University of Technology | Deng N.-Y.,China Agricultural University | Chen W.-J.,Zhejiang University of Technology
Knowledge-Based Systems | Year: 2013

Note that for GEPSVM proposed in [1], the predicted class of a testing point is determined by comparing two distances between the testing point and two hyperplanes, while the optimization problems are based on comparing two distances between a hyperplane and two kinds of the training points. So there exists some inconformity between the decision process and the training process. In this paper, we propose a new proximal classifier, called PCC for short, with consistency, which is always based on comparing two distances between a point (the testing point in the decision process and the training point in the training process) and two hyperplanes. This consistency not only makes our PCC to be more reasonable logically, but also naturally leads to a simpler decision function with less computation cost. Furthermore, in our PCC two general eigenvalue problems in GEPSVM are replaced by two simple eigenvalues problems with a parameter δ. In addition, different regularization terms are introduced in the formulation of our PCC, avoiding the singular problems possibly appeared in GEPSVM. Experimental results on several benchmark data sets show that our PCC is not only faster, but also has better generalization. © 2013 Elsevier B.V. All rights reserved.

Wang X.,Ludong University | Wang R.,Kunming Medical University | Zhang Y.,CAS Kunming Institute of Zoology | Zhang H.,China Agricultural University
Genome Biology and Evolution | Year: 2013

The druggable subset of the human genome, termed the "druggable genome, " provides the pharmaceutical industry with a unique opportunity for the advancement of new therapeutic interventions for a multitude of diseases and disorders. To date, there is no systematic assessment of the evolutionary history and nature of the defined druggable proteins derived from the contemporary druggable genome (i.e., proteins that bind or are predicted to bind with high affinity to a biologic). An understanding of drug-protein target interactions in specific cellular compartments is crucial for the optimal therapeutic delivery of pharmaceutical agents, as well as for preclinical drug trials in model animals. This study applied the concept of pharmacophylogenomics, the study of genes, evolution, and drug targets, to conduct an evolutionary survey of drug targets with respect to their sub cellular localizations. Using multiple model sand modes of druggable genome comparison, the results concordantly indicated that orthologous drug targets with anuclear localization inthehuman, macaque, mouse, and rat show edahigher trend for evolutionary conservation compared with drug targets in the cell membrane and the extracellular compartment. As such, this study provides important information regarding druggable protein targets and the druggable genome at the pharmacophylogenomics level. © The Author(s) 2013.

An Q.,Centers for Disease Control and Prevention | Prejean J.,Centers for Disease Control and Prevention | Harrison K.M.,Centers for Disease Control and Prevention | Fang X.,China Agricultural University
American Journal of Public Health | Year: 2013

Objectives. We examined the association between socioeconomic position (SEP) and HIV diagnosis rates in the United States and whether racial/ethnic disparities in diagnosis rates persist after control for SEP. Methods. We used cases of HIV infection among persons aged 13 years and older, diagnosed 2005 through 2009 in 37 states and reported to national HIV surveillance through June 2010, and US Census data, to examine associations between county-level SEP measures and 5-year average annual HIV diagnosis rates overall and among race/ethnicity-sex groups. Results. The HIV diagnosis rate was significantly higher for individuals in the low-SEP tertile than for those in the high-SEP tertile (rate ratios for low- vs high-SEP tertiles range = 1.68-3.38) except for White males and Hispanic females. The SEP disparities were larger for minorities than for Whites. Racial disparities persisted after we controlled for SEP, urbanicity, and percentage of population aged 20 to 50 years, and were high in the low-SEP tertile for males and in low- and high-SEP tertiles for females. Conclusions. Findings support continued prioritization of HIV testing, prevention, and treatment to persons in economically deprived areas, and Blacks of all SEP levels. Copyright © 2012 by the American Public Health Association®.

Gao Y.,University of Kassel | Ricoeur A.,University of Kassel | Zhang L.,China Agricultural University
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2011

Based on the complex potential method, plane problems of cubic quasicrystal media containing an elliptic hole subjected to uniform remote loadings are solved. The explicit solutions for the coupled fields are given in the closed form. Degenerating the elliptic hole into a crack, the asymptotic distribution of the phonon and phason stress fields near the crack tip exhibits inverse square root singularities. Explicit expressions for the stress intensity factors, crack opening displacements and strain energy release rate are also presented. © 2011 Elsevier B.V. All rights reserved.

Ying-fen W.,China Agricultural University
Journal of Convergence Information Technology | Year: 2011

A new early-warning method named leave-one-out classification mining is firstly introduced which can be derived directly by leave-one-out error bound. By kernel methods, linear classifier can be constructed. And early-warning feature selection algorithm is also proposed by minimizing leaver-oneout error bounds. In fact, early-warning problem has uncertain input or output. And by Newton's method, algorithm can be efficiently performed. Traditional eave-one-out classification can not solute uncertainty problem with probabilistic warning degrees or labels. Thus uncertainty leave-one-out classification model is proposed then which can deal with training data with uncertain labels. We interpreted the meaning of uncertainty and then derived the algorithm. The early-warning production problem is solved by our model and algorithm. Data experiment shows our classification model playing a good performance.

Zheng B.,China Agricultural University | Zheng B.,University of Pennsylvania | Jia T.,University of Pennsylvania | Walsh P.J.,University of Pennsylvania
Organic Letters | Year: 2013

An efficient catalytic system for the direct intermolecular α-arylation of acetamide derivatives with aryl chlorides is presented. Chemoselectivities up to 10:1 in the mono-and diarylation of acetamides were achieved by careful selection of bases, solvents, and stoichiometry. Bis-arylated amides were prepared in up to 95% yield. © 2013 American Chemical Society.

Dai Z.-L.,Nanjing Agricultural University | Wu G.,Texas A&M University | Wu G.,China Agricultural University | Zhu W.-Y.,Nanjing Agricultural University
Frontiers in Bioscience | Year: 2011

Bacteria in the gastrointestinal (GI) tract play an important role in the metabolism of dietary substances in the gut and extraintestinal tissues. Amino acids (AA) should be taken into consideration in the development of new strategies to enhance efficiency of nutrient utilization because they are not only major components in the diet and building blocks for protein but also regulate energy and protein homeostasis in organisms. The diversity of the AA-fermenting bacteria and their metabolic redundancy make them easier to survive and interact with their neighboring species or eukaryotic host during transition along GI tract. The outcomes of the interactions have important impacts on gut health and whole-body homeostasis. The AA-derived molecules produced by intestinal bacteria affect host health by regulating either host immunity and cell function or microbial composition and metabolism. Emerging evidence shows that dietary factors, such as protein, non-digestible carbohydrates, probiotics, synbiotics and phytochemicals, modulate AA utilization by gut microorganisms. Interdisciplinary research involving nutritionists and microbiologists is expected to rapidly expand knowledge about crucial roles for AA in gut ecology and host health.

Liu W.,Fuyang Normal College | Zhao C.,China Agricultural University
Biochemical Genetics | Year: 2011

The zebra finch (Taeniopygia guttata) is an established organism for developmental, behavioral, and neurological research. In this study, we conducted a genomewide survey using the zebra finch genome project databases and identified 86 bHLH sequences in silico in the zebra finch genome. Phylogenetic analysis revealed that 85 proteins belong to 38 families with 29, 18, 18, 3, 11, and 6 bHLH members in supergroups A, B, C, D, E, and F, respectively. One orphan member belonged to none of these groups. Comparisons of zebra finch with chicken and human bHLH repertoires suggested that both humans and birds have a number of lineage-specific bHLH members. Chromosome distribution patterns and phylogenetic analysis suggest that the zebra finch bHLH members should have arisen through gene duplication. This study provides useful information for further research using zebra finch as a model system. © 2010 Springer Science+Business Media, LLC.

Hou X.-L.,China Agricultural University | Wu Y.-L.,Ningbo Academy of Agricultural science | Yang T.,Ningbo Academy of Agricultural science | Du X.-D.,Henan Agricultural University
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2013

A simple and cost-effective pre-treatment procedure was developed for 18 sulfonamides in pork using dispersive solid phase extraction (dSPE) with multi-walled carbon nanotubes (MWCNTs). The sample was analysed after purification by ultra high-performance liquid chromatography-positive electrospray ionisation tandem mass spectrometry (UHPLC-ESI-MS/MS). After extraction with phosphate buffer (pH 6.0), a dSPE procedure was conducted with MWCNTs. The pH value of the extract, extraction time with MWCNTs, type and amount of MWCNTs and type of eluent were optimised to increase the sample throughput and sensitivity. The samples were quantified using sulfamethazine-13C6 as an internal standard. The recoveries of the target compounds from the pork samples were most efficient when 150mg of MWCNTs with an outer diameter of less than 8nm and a length of 0.5-2μm was used. A mixture of acetonitrile/50mM ammonium acetate (95:5, v/v) was shown to be the most suitable solvent for desorbing the compounds from the MWCNTs. The proposed method was validated according to the European Commission Decision 2002/657/EC, which determines linearity, specificity, decision limit (CCα), detection capability (CCβ), recovery, precision and stability. © 2013 Elsevier B.V.

Zhu H.,University of Regina | Huang G.H.,University of Regina | Guo P.,China Agricultural University
Water, Air, and Soil Pollution | Year: 2012

A simulation-based interval-fuzzy nonlinear programming (SIFNP) approach was developed for seasonal planning of stream water quality management. The techniques of inexact modeling, nonlinear programming, and interval-fuzzy optimization were incorporated within a general framework. Based on a multi-segment stream water quality simulation model, dynamic waste assimilative capacity of a river system within a multi-season context was considered in the optimization process. The method could not only address complexities of various system uncertainties but also tackle nonlinear environmental-economic interrelationships in water quality management problems. In addition, interval-fuzzy numbers were introduced to reflect the dual uncertainties, i.e., imprecision associated with fixing the lower and upper bounds of membership functions. The proposed method was applied to a case of water quality management in the Guoyang section of the Guo River in China. Interval solutions reflecting the inherent uncertainties were generated, and a spectrum of cost-effective schemes for seasonal water quality management could thus be obtained by adjusting different combinations of the decision variables within their solution intervals. The results indicated that SIFNP could effectively communicate dual uncertainties into the optimization process and help decision makers to identify desired options under various complexities of system components. © Springer Science+Business Media B.V. 2011.

Sun D.,China Agricultural University
International Journal of Applied Earth Observation and Geoinformation | Year: 2015

This study was to detect dryland degradation coupling linear spectral unmixing model of Landsat images with syndrome concept in temperate dryland system, Minqin, China. The phenological contrast and complementation between green vegetation fraction in summer, sandland fraction and saline land fraction in spring, was firstly structured to quantify degradation characteristics by simple correlation analysis with ground data. The spatiotemporal patterns of the three degradation indicators were interpreted with the help "dust bowl" syndrome, qualitatively deciphered the degradation causal clusters, loops and important consequences in the study area. The results indicate water-using and distribution pattern was changed, agricultural intensity and productivity increased, salinization lessened in oasis, whereas sandification risk heightened. This approach developed in this study, has the potentially broad applicability, for dryland system monitoring and modelling. © 2015 Elsevier B.V.

Luo L.,CAS Institute of Zoology | Luo L.,University of Chinese Academy of Sciences | Sun Y.-J.,China Agricultural University | Wu Y.-J.,CAS Institute of Zoology
Insect Biochemistry and Molecular Biology | Year: 2013

Many insects have evolved resistance to abamectin but the mechanisms involved in this resistance have not been well characterized. P-glycoprotein (P-gp), an ATP-dependent drug-efflux pump transmembrane protein, may be involved in abamectin resistance. We investigated the role of P-gp in abamectin (ABM) resistance in Drosophila using an ABM-resistant strain developed in the laboratory. A toxicity assay, Western blotting analysis and a vanadate-sensitive ATPase activity assay all demonstrated the existence of a direct relationship between P-gp expression and ABM resistance in these flies. Our observations indicate that P-gp levels in flies' heads were higher than in their thorax and abdomen, and that both P-gp levels and LC50 values were higher in resistant than in susceptible and P-gp-deficient strains. In addition, P-gp levels in the blood-brain barrier (BBB) of resistant flies were higher than in susceptible and P-gp-deficient flies, which is further evidence that a high level of P-gp in the BBB is related to ABM resistance. Furthermore, we found greater expression of Drosophila EGFR (dEGFR) in the resistant strain than in the susceptible strain, and that the level of Drosophila Akt (dAkt) was much higher in resistant than in susceptible flies, whereas that in P-gp-deficient flies was very low. Compared to susceptible flies, P-gp levels in the resistant strain were markedly suppressed by the dEGFR and dAkt inhibitors lapatinib and wortmannin. These results suggest that the increased P-gp in resistant flies was regulated by the dEGFR and dAkt pathways and that increased expression of P-gp is an important component of ABM resistance in insects. © 2013 Elsevier Ltd.

Xu Y.,China Agricultural University
Journal of Information Science and Engineering | Year: 2015

Twin support vector regression (TSVR), as an effective regression machine, solves a pair of smaller-sized quadratic programming problems (QPPs) rather than a single large one as in the classical support vector regression (SVR), which makes the learning speed of TSVR approximately 4 times faster than that of the conventional SVR. However, the empirical risk minimization principle is implemented in TSVR, which reduces its generalization ability to a certain extent. In order to improve the prediction accuracy and stability of algorithm, we propose a novel TSVR for the regression problem by introducing a regularization term into the objective function, which ensures the new algorithm implements the structural risk minimization principle instead of the empirical risk minimization principle. Moreover, the up-and down-bound functions obtained in our algorithm are as parallel as possible. Thus it ensures that our proposed algorithm yields lower prediction error and lower standard deviation in theory. The experimental results on one artificial dataset and six benchmark datasets indicate the feasibility and validity of our novel TSVR.

Chen J.,China Agricultural University
Luminescence | Year: 2014

White light-emitting diodes (LEDs) for green lighting are new solutions for energy saving and environmental protection. Ca3SiO4Cl2:Ce,Eu is an efficient phosphor for white LEDs. Effective energy transfer from Ce3+ to Eu2+ occurs in Ca3SiO4Cl2:Ce,Eu due to good spectrum overlap between the emission band of Ca3SiO4Cl2:Ce and the excitation band of Ca3SiO4Cl2:Eu, and hues vary systematically from blue to green at different Ce concentrations. A great improvement in the luminescent property of Ca3SiO4Cl2:Eu has been observed on Ce3+ doping, which is attributed to energy transfer from Ce3+ to Eu2+ and an increase in the number of luminescent centers (Eu2+) on Ce doping. The optimal sample has a quantum efficiency of up to 75%, and can be an efficient green phosphor for white LEDs. © 2014 John Wiley & Sons, Ltd.

Wang X.-Y.,Peking University | Lin H.-R.,Peking University | Lei T.,Peking University | Yang D.-C.,Peking University | And 4 more authors.
Angewandte Chemie - International Edition | Year: 2013

Boron-nitrogen units were incorporated into thiophene-fused polycyclic aromatic compounds. Organic field-effect transistors based on these azaborine compounds were fabricated, demonstrating a novel engineering concept of organic semiconductors and providing opportunities of a broad class of BN-containing compounds for application in future organic electronic devices (see picture; μFET=hole mobility). © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lan B.,China Agricultural University
Communications in Computer and Information Science | Year: 2012

In this paper, we put forward a kind of set up precision agriculture information service system. The key to the system, based on geographic information system (GIS) and global positioning system is built on concatenating data sets. The geographic information system (GIS) and global positioning system integration technology is a technical and social development is. A word, precision agriculture information system, based on GIS and GPS research shows that this paper is just a simple example to show brings the advantage, geographic information system (GIS) and global positioning system integration technology. Therefore, we have more work to do, to realize the actual precision agriculture information system based on GIS and GPS. © 2012 Springer-Verlag Berlin Heidelberg.

Dumbrell A.J.,University of York | Dumbrell A.J.,University of Essex | Ashton P.D.,University of York | Aziz N.,University of York | And 5 more authors.
New Phytologist | Year: 2011

Understanding the dynamics of rhizosphere microbial communities is essential for predicting future ecosystem function, yet most research focuses on either spatial or temporal processes, ignoring combined spatio-temporal effects. Using pyrosequencing, we examined the spatio-temporal dynamics of a functionally important community of rhizosphere microbes, the arbuscular mycorrhizal (AM) fungi. We sampled AM fungi from plant roots growing in a temperate grassland in a spatially explicit manner throughout a year. Ordination analysis of the AM fungal assemblages revealed significant temporal changes in composition and structure. Alpha and beta diversity tended to be negatively correlated with the climate variables temperature and sunshine hours. Higher alpha diversity during colder periods probably reflects more even competitive interactions among AM fungal species under limited carbon availability, a conclusion supported by analysis of beta diversity which highlights how resource limitation may change localized spatial dynamics. Results reveal distinct AM fungal assemblages in winter and summer at this grassland site. A seasonally changing supply of host-plant carbon, reflecting changes in temperature and sunshine hours, may be the driving force in regulating the temporal dynamics of AM fungal communities. Climate change effects on seasonal temperatures may therefore substantially alter future AM fungal community dynamics and ecosystem functioning. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

Kuleszewicz K.,Imperial College London | Fu X.,Imperial College London | Fu X.,China Agricultural University | Kudo N.R.,Imperial College London
Cell Division | Year: 2013

Background: Sister chromatid cohesion mediated by the cohesin complex is essential for accurate chromosome segregation during mitosis and meiosis. Loading of cohesin onto chromosomes is dependent on another protein complex called kollerin, containing Nipbl/Scc2 and Mau2/Scc4. Nipbl is an evolutionarily conserved large protein whose haploinsufficiency in humans causes a developmental disorder called Cornelia de Lange syndrome. Although the function of Nipbl homologues for chromosome cohesion in meiotic cells of non-vertebrate models has been elucidated, Nipbl has not been characterized so far in mammalian spermatocytes or oocytes.Findings: Here we describe our analyses on the expression and localization of Nipbl in nuclei of mouse spermatocytes and oocytes at different stages of meiotic prophase. In both spermatocytes and oocytes we found that Nipbl is associated with the axial/lateral element of the synaptonemal complex (AE/LE) to which cohesin also localizes. Interestingly, Nipbl in spermatocytes, but not in oocytes, dissociates from the AE/LE at mid-pachytene stage coincident with completion of DNA double-strand break repair.Conclusions: Our data propose that cohesin loading activity is maintained during early stages of meiotic prophase in mammalian spermatocytes and oocytes. © 2013 Kuleszewicz et al.; licensee BioMed Central Ltd.

Guo P.,China Agricultural University | Huang G.H.,University of Regina | Huang G.H.,North China Electrical Power University | Zhu H.,University of Regina | Wang X.L.,Tianjin University
Environmental Modelling and Software | Year: 2010

In this study, a fuzzy stochastic two-stage programming (FSTP) approach is developed for water resources management under uncertainty. The concept of fuzzy random variable expressed as parameters' uncertainties with both stochastic and fuzzy characteristics was used in the method. FSTP has advantages in uncertainty reflection and policy analysis. FSTP integrates the fuzzy robust programming, chance-constrained programming and two-stage stochastic programming (TSP) within a general optimization framework. FSTP can incorporate pre-regulated water resources management policies directly into its optimization process. Thus, various policy scenarios with different economic penalties (when the promised amounts are not delivered) can be analyzed. FSTP is applied to a water resources management system with three users. The results indicate that reasonable solutions were generated, thus a number of decision alternatives can be generated under different levels of stream flows, α-cut levels and different levels of constraint-violation probability. The developed FSTP was also compared with TSP to exhibit its advantages in dealing with multiple forms of uncertainties. © 2010 Elsevier Ltd.

Xing J.-Z.,Tianjin Polytechnic University | Wang Y.-G.,China Agricultural University
Archive of Applied Mechanics | Year: 2013

A general model for vibration of beams restrained with two transversal and two rotational elastic springs subject to a constant axially load is presented. The frequency equations and the shape functions are derived analytically. The proposed model can be employed for simulating the dynamic responses of elastically supported beams in tension or compression for most classical boundary conditions. Some simplifications in the degenerate cases are deduced to evaluate the effectiveness of the model. Numeric examples are given for engineering applications. This model unifies most of the previous vibration models and provides a convenient tool for the analyses of various beam vibrations in tension and compression conditions. © 2012 Springer-Verlag.

Abdollahi A.,University of Connecticut | Zhang P.,University of Connecticut | Xue H.,China Agricultural University | Li S.,University of Connecticut
IEEE Transactions on Power Delivery | Year: 2013

Recently, the subspace-least mean square (S-LMS) method has been proposed for power system measurement. The high accuracy and high resolution of the S-LMS method are achieved at the cost of being computationally expensive. In this paper, the S-LMS method is enhanced in two aspects: 1) speed and 2) accuracy. The computation burden of S-LMS is significantly reduced in three ways: 1) exploring the sparsity of power system signals; 2) using an iterative multisectional search scheme; and 3) the combination of these two techniques. Further, detection of the harmonic components based on the fact that they are multiples of the fundamental frequency has been effectively employed, resulting in a more accurate and robust algorithm for fundamental and harmonic estimation in the presence of noise. The enhanced S-LMS algorithm, which detects harmonics more accurately, is more than 150 times faster than the original S-LMS if the interharmonic level is negligibly low. The dynamic behavior of the method is discussed and the method is compared with Prony and DFT. Simulations show the methods are highly resilient to off-nominal conditions and noise. © 1986-2012 IEEE.

Shen L.,Beijing Wuzi University | Li Z.,Texas A&M University | He P.,China Agricultural University
Electrochemistry Communications | Year: 2010

In this paper, the voltammetric characteristics of several β2-agonists including salbutamol, ractopamine, bamethane, isoxsuprine, ritodrine, fenoterol, terbutaline, metaproterenol, clenbuterol, clenproperol, mabuterol, cimaterol, cimbuterol and brombuterol were comparatively evaluated using graphite nanosheet (GN) modified glassy carbon (GC) electrodes. All the compounds can be oxidized at GN modified electrodes with enhanced peak current and reduced peak potential compared with naked GC electrodes. The electrochemical behaviors of the compounds are different due to different substituent groups on the aromatic rings. For the first time, an ECE process was observed for salbutamol and its analogues. The capability of determining β2-agonists individually or simultaneously from aqueous solution using differential pulse voltammetry and amperometry with the developed electrode was also investigated. © 2010 Elsevier B.V. All rights reserved.

Qiu L.-C.,China Agricultural University
Industrial and Engineering Chemistry Research | Year: 2013

We present a numerical method combining the smoothed particle hydrodynamics (SPH) and discrete element method (DEM) to model liquid flows in the presence of solid particles. This approach does not require a computational mesh, nor does it rely on empirical models to couple the liquid and solid phases. In the present method, the SPH is applied to simulate the liquid flows, and the DEM together with interaction laws based on the theoretical contact mechanics is introduced into the SPH method to calculate the effects of contact between solid particles and between solid particles and walls. The introduced DEM model is verified by experimental analyses for the collapse of six solid cylinder layers. The proposed DEM-SPH model is then applied to simulate the free falling of a rigid sphere in water with a free surface. © 2013 American Chemical Society.

Guangli L.,China Agricultural University | Chengyu S.,Shandong University
Journal of Convergence Information Technology | Year: 2011

Tariff is an important tool for China international trade. To make Rationalizing tariff policy needs information technology and decision support. First, tariff database management system is designed and implemented, based on tariff government management demand, by which one can make various forms of queries and updating. Database covers eight parts such as agricultural product and chemical products and machinery and so on. Then, based on work needs an intelligent word document extraction system is building by which can easy to achieve data import from Excel files and generate tariff word document. China tariff system can play a decision support role for tariff business by testing.

Carberry P.S.,CSIRO | Liang W.-L.,Agricultural University of Hebei | Twomlow S.,International Fund for Agricultural Development | Holzworth D.P.,CSIRO | And 5 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2013

Global food security requires eco-efficient agriculture to produce the required food and fiber products concomitant with ecologically efficient use of resources. This eco-efficiency concept is used to diagnose the state of agricultural production in China (irrigated wheat-maize double-cropping systems), Zimbabwe (rainfed maize systems), and Australia (rainfed wheat systems). More than 3,000 surveyed crop yields in these three countrieswere compared against simulated grain yields at farmer-specified levels of nitrogen (N) input. Many Australian commercial wheat farmers are both close to existing production frontiers and gain little prospective return from increasing their N input. Significant losses of N from their systems, either as nitrous oxide emissions or as nitrate leached from the soil profile, are infrequent and at lowintensities relative to their level of grain production. These Australian farmers operate close to ecoefficient frontiers in regard to N, and so innovations in technologies and practices are essential to increasing their production without added economic or environmental risks. In contrast, many Chinese farmers can reduce N input without sacrificing production through more efficient use of their fertilizer input. In fact, there are real prospects for the double-cropping systems on the North China Plain to achieve both production increases and reduced environmental risks. Zimbabwean farmers have the opportunity for significant production increases by both improving their technical efficiency and increasing their level of input; however, doing so will require improved management expertise and greater access to institutional support for addressing the higher risks. This paper shows that pathways for achieving improved eco-efficiency will differ among diverse cropping systems.

Shao Y.-H.,Zhejiang University of Technology | Deng N.-Y.,China Agricultural University | Chen W.-J.,Zhejiang University of Technology | Wang Z.,Jilin University
IEEE Signal Processing Letters | Year: 2013

In this letter, we propose an improved version of generalized eigenvalue proximal support vector machine (GEPSVM), called IGEPSVM for short. The main improvements are 1) the generalized eigenvalue decomposition is replaced by the standard eigenvalue decomposition, resulting in simpler optimization problems without the possible singularity. 2) An extra meaningful parameter is introduced, resulting in the stronger classification generalization ability. Experimental results on both the artificial datasets and several benchmark datasets show that our IGEPSVM is superior to GEPSVM in both computation time and classification accuracy. © 2013 IEEE.

Borras Jr. S.M.,International Institute of Social Studies | Franco J.C.,Transnational Institute | Wang C.,China Agricultural University
Globalizations | Year: 2013

The emergence of 'flex crops and commodities' within a fluid international food regime transition, the rise of BRICS and middle-income countries, and the revalued role of nation-states are critical context for land grabbing. These global transformations that shape and are reshaped by contemporary land grabbing have resulted in the emergence of competing interpretations of the meaning of such changes, making the already complex governance terrain even more complicated. We are witnessing a three-way political contestation at the global level to control the character, pace, and trajectory of discourse, and the instruments in and practice of land governance. These are 'regulate to facilitate', 'regulate to mitigate negative impacts and maximize opportunities', and 'regulate to block and rollback' land grabbing. Future trajectories in land grabbing and its governance will be shaped partly by the balance of state and social forces within and between these three political tendencies. Given this an unfolding global development, this article offers a preliminary analysis by mapping under-explored areas of inquiry and puts forward initial ways of questioning, rather than firm arguments based on complete empirical material. © 2013 Copyright Taylor and Francis Group, LLC.

Liu X.,China Agricultural University
China Agricultural Economic Review | Year: 2014

Purpose - What this paper aims to tackle is how much did the return of rural migrant labor during the financial crisis affect China's GDP and the growth rate of the national economy. Design/methodology/approach - This paper constructs a computable general equilibrium (CGE) model and uses data of China's 2007 Input-Output Table to analyze the impact of the return of rural migrant labor on China's economy during the financial crisis. Findings - The results show that the return of rural migrant labor during the financial crisis had substantial impacts on China's economy. The national GDP decreased by about 0.499-1.463 percent, mainly due to the number of rural labor who migrated from the non-agricultural sector to agriculture. Of the major sectors of economy, the manufacturing, construction and other services sectors were the most affected. Originality/value - This paper assesses the impacts of return of rural migrant labor during the financial crisis on China's GDP and the growth rate of the national economy. Copyright © 2014 Emerald Group Publishing Limited. All rights reserved.

Gu B.,Zhejiang University | Ju X.,China Agricultural University | Chang J.,Zhejiang University | Ge Y.,Zhejiang University | Vitousek P.M.,Stanford University
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

Reactive nitrogen (Nr) plays a central role in food production, and at the same time it can be an important pollutant with substantial effects on air and water quality, biological diversity, and human health. China now creates far more Nr than any other country. We developed a budget for Nr in China in 1980 and 2010, in which we evaluated the natural and anthropogenic creation of Nr, losses of Nr, and transfers among 14 subsystems within China. Our analyses demonstrated that a tripling of anthropogenic Nr creation was associated with an even more rapid increase in Nr fluxes to the atmosphere and hydrosphere, contributing to intense and increasing threats to human health, the sustainability of croplands, and the environment of China and its environs. Under a business as usual scenario, anthropogenic Nr creation in 2050 would more than double compared with 2010 levels, whereas a scenario that combined reasonable changes in diet, N use efficiency, and N recycling could reduce N losses and anthropogenic Nr creation in 2050 to 52% and 64% of 2010 levels, respectively. Achieving reductions in Nr creation (while simultaneously increasing food production and offsetting imports of animal feed) will require much more in addition to good science, but it is useful to know that there are pathways by which both food security and health/environmental protection could be enhanced simultaneously. © 2015, National Academy of Sciences. All rights reserved.

Chen Y.,China Agricultural University | Liu P.,CAS Institute of Botany | Hoehenwarter W.,University of Vienna | Lin J.,CAS Institute of Botany
Journal of Proteome Research | Year: 2012

The pollen tube is a tip-growing system that delivers sperm to the ovule and thus is essential for sexual plant reproduction. Sucrose and other microelements act as nutrients and signaling molecules through pathways that are not yet fully understood. Taking advantage of high-throughput liquid chromatography coupled to mass spectrometry (LC-MS), we performed a label-free shotgun proteomic analysis of pollen in response to nutrient limitation using mass accuracy precursor alignment. We compared 168 LC-MS analyses and more than 1 million precursor ions and could define the proteomic phenotypes of pollen under different conditions. In total, 166 proteins and 42 phosphoproteins were identified as differentially regulated. These proteins are involved in a variety of signaling pathways, providing new insights into the multifaceted mechanism of nutrient function. The phosphorylation of proteins involved in cytoskeleton dynamics was found to be specifically responsive to Ca2+ and sucrose deficiency, suggesting that sucrose and extracellular Ca2+ influx are necessary for the maintenance of cytoskeleton polymerization. Sucrose limitation leads to widespread accumulation of proteins involved in carbohydrate metabolism and protein degradation. This highlights the wide range of metabolic and cellular processes that are modulated by sucrose but complicates dissection of the signaling pathways. © 2012 American Chemical Society.

Zhang W.,Fuzhou University | Zhang W.,North Carolina State University | Yuan W.,North Carolina State University | Zhang X.,China Agricultural University | Coronado M.,North Carolina State University
Applied Energy | Year: 2012

This work reports the use of mid- and near-infrared spectroscopy (MIR and NIR) to predict the kinematic and dynamic viscosities of biodiesel-diesel blends. A partial least square regression (PLSR) modeling method was employed to develop the calibration models based on information from four commonly used biodiesel and three different commercial diesel fuels. For MIR spectroscopy, wavelengths in the fingerprint region of 550-1500cm-1 were chosen for developing the model. The root mean square error of prediction (RMSEP) for kinematic viscosity and dynamic viscosity were 0.114 and 0.119mm2/s, respectively, based on the validation set that consisted of 26 biodiesel-diesel blend samples made of six different biodiesel and three different diesel fuels. For the NIR spectroscopy, the PLSR model established using the spectral regions of 1100-1500nm, 1600-1700nm, and 1800-2200nm obtained better results. The RMSEP were 0.070mm2/s for kinematic viscosity and 0.062mm2/s for dynamic viscosity prediction. The results indicated that both MIR and NIR can be used to accurately predict the viscosities of biodiesel-diesel blends, but better results can be obtained using NIR spectroscopy. © 2012 Elsevier Ltd.

Li C.,Hebei University of Engineering | Wu Y.L.,Ningbo Agriculture Products Quality Detector Center | Shen J.Z.,China Agricultural University
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2010

An analytical method for the simultaneous determination of Sudan dyes (Sudan Red G, Sudan I, Sudan II, Sudan III, Sudan Red 7B and Sudan IV) and Para Red in food by ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-ESI-MS/MS) was developed. Samples were extracted with acetonitrile, and water added into the extract. The supernatant was analysed by UPLC-MS/MS after refrigeration and centrifugation. The sample was separated on an Acquity BEH C18 column, and detected by MS/MS with the multiple reaction monitoring mode. Matrix calibration was used for quantitative testing of the method. The linear matrix calibrations of Sudan dyes and Para Red were 2-50 and 10-250 ng g-1, respectively, and the regression coefficients were >0.9945. The recoveries were 83.4-112.3% with good coefficients of variation of 2.0-10.8%. The limits of detection were between 0.3 and 1.4 ng g-1 for the six Sudan dyes, and between 3.7 and 6.0 ng g-1 for Para Red. The limits of quantification were between 0.9 and 4.8 ng g-1 for the six Sudan dyes, and between 12.2 and 19.8 ng g-1 for Para Red. © 2010 Taylor & Francis.

Ng T.B.,Chinese University of Hong Kong | Wong J.H.,Chinese University of Hong Kong | Wang H.,China Agricultural University
Current Protein and Peptide Science | Year: 2010

The intent of this article is to review recent literature on ribosome inactivating proteins (RIPs) including isolation and characterization of new RIPs, studies on the crystal structures and mechanisms of actions of RIPs, the use of saporin-based neurotoxins to selectively lesion cholinergic neurons in neuroscience research, and the use of RIP-based conjugates and immunotoxins in anticancer therapy. © 2010 Bentham Science Publishers Ltd.

Liu G.-H.,Chinese Academy of Agricultural Sciences | Liu G.-H.,Hunan Agricultural University | Shao R.,University of The Sunshine Coast | Li J.-Y.,Chinese Academy of Agricultural Sciences | And 4 more authors.
BMC Genomics | Year: 2013

Background: Analyses of mitochondrial (mt) genome sequences in recent years challenge the current working hypothesis of Nematoda phylogeny proposed from morphology, ecology and nuclear small subunit rRNA gene sequences, and raise the need to sequence additional mt genomes for a broad range of nematode lineages.Results: We sequenced the complete mt genomes of three Ascaridia species (family Ascaridiidae) that infest chickens, pigeons and parrots, respectively. These three Ascaridia species have an identical arrangement of mt genes to each other but differ substantially from other nematodes. Phylogenetic analyses of the mt genome sequences of the Ascaridia species, together with 62 other nematode species, support the monophylies of seven high-level taxa of the phylum Nematoda: 1) the subclass Dorylaimia; 2) the orders Rhabditida, Trichinellida and Mermithida; 3) the suborder Rhabditina; and 4) the infraorders Spiruromorpha and Oxyuridomorpha. Analyses of mt genome sequences, however, reject the monophylies of the suborders Spirurina and Tylenchina, and the infraorders Rhabditomorpha, Panagrolaimomorpha and Tylenchomorpha. Monophyly of the infraorder Ascaridomorpha varies depending on the methods of phylogenetic analysis. The Ascaridomorpha was more closely related to the infraorders Rhabditomorpha and Diplogasteromorpha (suborder Rhabditina) than they were to the other two infraorders of the Spirurina: Oxyuridorpha and Spiruromorpha. The closer relationship among Ascaridomorpha, Rhabditomorpha and Diplogasteromorpha was also supported by a shared common pattern of mitochondrial gene arrangement.Conclusions: Analyses of mitochondrial genome sequences and gene arrangement has provided novel insights into the phylogenetic relationships among several major lineages of nematodes. Many lineages of nematodes, however, are underrepresented or not represented in these analyses. Expanding taxon sampling is necessary for future phylogenetic studies of nematodes with mt genome sequences. © 2013 Liu et al.; licensee BioMed Central Ltd.

Fan J.,China Agricultural University | Fan J.,John Innes Center | Doerner P.,University of Edinburgh | Doerner P.,Joseph Fourier University
Current Opinion in Plant Biology | Year: 2012

Nonhost resistance (NHR), in which a successful pathogen on some plants fails to overcome host barriers on others, has attracted much attention owing to its potential for robust crop improvement. Recent advances reveal that a multitude of underlying mechanisms contribute to NHR, ranging from components shared with recognition-based defenses up to recessive susceptibility factors involved in plant primary metabolism. Most NHR appears multi-factorial and quantitative. This implies that there is no single, 'silver bullet' NHR mechanism that can be used to broadly restrict pathogens in many or all crops. © 2012 Elsevier Ltd.

Lai J.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Luo Y.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Ren L.,China Agricultural University
Soil Science Society of America Journal | Year: 2010

The double-ring infiltrometer is widely used to measure soil saturated hydraulic conductivity in the field. Both the inner ring size and outer ring size (two factors in the buffer index) of an infiltrometer affect the measurements of saturated hydraulic conductivity. Few systematic studies have been conducted to investigate the combined effects of the inner and outer ring sizes of a double-ring infiltrometer on the measurements of field saturated hydraulic conductivity. A total of 7224 numerical simulations were conducted to investigate the optimum combination of inner and outer ring sizes for reliable saturated hydraulic conductivity measurements by using 24 infiltrometers with six inner ring diameters ( 10,20,40,80,120, and 200 cm) and, for each ring diameter, four buffer indices [b = 0.2,0.33,0.5, and 0.71). Results demonstrated that the inner ring size is a more important factor to be considered than the buffer index itself (or the outer ring size) in practice, and a larger inner ring diameter assembled with an outer ring (in most cases, with diameter ≥ 80 cm and b ≥ 0.33) is recommended to obtain reliable in situ measurement of soil field saturated hydraulic conductivity. © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA All rights reserved.

Gao Y.,China Agricultural University | Gao Y.,TU Bergakademie Freiberg
Acta Mechanica | Year: 2010

Without employing ad hoc assumptions, various equations and solutions for quasicrystal beams are deduced systematically and directly from the plane problem of one-dimensional quasicrystals. These equations and solutions can be used to construct the exact theory of deep beams for extension or compression and bending deformation forms. A method for the solution of two-dimensional equations is presented, and with the method the exact theory can now be explicitly established from the general solution of quasicrystals and the Lur'e method. The exact governing equations for beams under transverse loadings are derived directly from the exact beam theory. In three illustrative examples of quasicrystal beams it is shown that the exact or accurate solutions can be obtained by use of the exact theory. © Springer-Verlag 2009.

Sunkara L.T.,Oklahoma State University | Zeng X.,Oklahoma State University | Zeng X.,China Agricultural University | Curtis A.R.,Oklahoma State University | Zhang G.,Oklahoma State University
Molecular Immunology | Year: 2014

Host defense peptides (HDP) have both microbicidal and immunomodulatory properties. Specific induction of endogenous HDP synthesis has emerged as a novel approach to antimicrobial therapy. Cyclic adenosine monophosphate (cAMP) and butyrate have been implicated in HDP induction in humans. However, the role of cAMP signaling and the possible interactions between cAMP and butyrate in regulating HDP expression in other species remain unknown. Here we report that activation of cAMP signaling induces HDP gene expression in chickens as exemplified by β-defensin 9 (AvBD9). We further showed that, albeit being weak inducers, cAMP agonists synergize strongly with butyrate or butyrate analogs in AvBD9 induction in macrophages and primary jejunal explants. Additionally, oral supplementation of forskolin, an adenylyl cyclase agonist in the form of a Coleus forskohlii extract, was found to induce AvBD9 expression in the crop of chickens. Furthermore, feeding with both forskolin and butyrate showed an obvious synergy in triggering AvBD9 expression in the crop and jejunum of chickens. Surprisingly, inhibition of the MEK-ERK mitogen-activated protein kinase (MAPK) pathway augmented the butyrate-FSK synergy, whereas blocking JNK or p38 MAPK pathway significantly diminished AvBD9 induction in chicken macrophages and jejunal explants in response to butyrate and FSK individually or in combination. Collectively, these results suggest the potential for concomitant use of butyrate and cAMP signaling activators in enhancing HDP expression, innate immunity, and disease resistance in both animals and humans. © 2013 Elsevier Ltd.

Chen G.-Q.,Tsinghua University | Wang Y.,China Agricultural University
Chinese Journal of Polymer Science (English Edition) | Year: 2013

Microbial polyhydroxyalkanoates (PHAs) are a family of biopolyesters produced by many wild type and engineered bacteria. PHAs have diverse structures accompanied by flexible thermal and mechanical properties. Combined with their in vitro biodegradation, cell and tissue compatibility, PHAs have been studied for medical applications, especially medical implants applications, including heart valve tissue engineering, vascular tissue engineering, bone tissue engineering, cartilage tissue engineering, nerve conduit tissue engineering as well as esophagus tissue engineering. Most studies have been conducted in the authors' lab in the past 20+ years. Recently, mechanism on PHA promoted tissue regeneration was revealed to relate to cell responses to PHA biodegradation products and cell-material interactions mediated by microRNA. Very importantly, PHA implants were found not to cause carcinogenesis during long-term implantation. Thus, PHAs should have a bright future in biomedical areas. © 2013 Chinese Chemical Society, Institute of Chemistry, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg.

Zhang Y.,University of Idaho | Gao H.,China Agricultural University | Guo Y.,University of Idaho | Joo Y.-H.,University of Idaho | Shreeve J.M.,University of Idaho
Chemistry - A European Journal | Year: 2010

N,N-Dimethylhydrazinium dicyanamide and nitrocyanamide ionic liquids (ILs) were prepared by quaterization of N,N-dimethylhydrazine with alkyl halides followed by metathesis reactions with silver dicyanamide or silver nitrocyanamide. The key physicochemical properties, such as melting point and decomposition temperatures, density, viscosity, heat of formation, detonation pressure and velocity, and specific impulse were measured/calculated. The impact of anions and alkyl substituted cations on these properties is demonstrated. Droplet tests with white-fuming nitric acid (WFNA) as an oxidizer were utilized to show that the 14 new N,N-dimethylhydrazinium salts are hypergolic with ignition delay (ID) times ranging from 22 to 1642 ms, thereby suggesting that some may have potential as bipropellants. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

Yu L.,University of Florida | Xiong Y.-M.,China Agricultural University | Polfer N.C.,University of Florida
Analytical Chemistry | Year: 2011

We report trends in the theoretically derived number of compositionally distinct peptides (i.e., peptides made up of different amino acid residues) up to a nominal mass of 1000. A total of 21 amino acid residues commonly found in proteomics studies are included in this study, 19 natural, nonisomeric amino acid residues as well as oxidated methione and acetamidated cysteine. The number of possibilities is found to increase in an exponential fashion with increasing nominal mass, and the data show a periodic oscillation that starts at mass ∼200 and continues throughout to 1000. Note that similar effects are reported in the companion article on fragment ions from electron capture/transfer dissociation (ECD/ETD) (Mao et al. Anal. Chem.2011, DOI: 10.1021/ac201619t). The spacing of this oscillation is ∼15 mass units at lower masses and ∼14 mass units at higher nominal masses. This correlates with the most common mass differences between the amino acid building blocks. In other words, some mass differences are more common than others, thus determining the periodicity in this data. From an analytical point of view, nominal masses with a larger number of compositionally distinct peptides include a substantial number of isomers, which cannot be separated based on mass. Consequently, even ultrahigh mass accuracy (i.e., 0.5 ppm) does not lead to a substantially enhanced rate of identification. Conversely, for adjacent nominal masses with a lower number of isomers, moderately accurate mass (i.e., 10 ppm) gives a higher degree of certainty in identification. These effects are limited to the mass range between 200 and 500 Da. At higher masses, the percentage of uniquely identified peptides drops off to close to zero, independent of nominal mass, due the inherently high number of isomers. While the exact number of isobars/isomers at each nominal mass depends on the amino acid building blocks that are considered, the periodicity in the data is found to be remarkably robust; for instance, inclusion of phosphorylated residues barely affects the pattern at lower masses (i.e., <500 Da). © 2011 American Chemical Society.

Jia H.,Tsinghua University | Yao H.,China Agricultural University | Yu S.L.,University of Virginia
Frontiers of Environmental Science and Engineering | Year: 2013

China is at present experiencing a very rapid urbanization process, which has brought a number of adverse impacts upon the water environment. In particular, urban runoff quantity and quality control have emerged as one of the key concerns for municipal officials. One of the strategies being considered is the use of a Low Impact Development type of Best Management Practices (LID BMPs) for urban storm water runoff quantity and quality control. In this paper, the situation surrounding urban runoff control in China is reviewed first. Then the conventional strategy and technologies for the construction and management of urban drainage systems are discussed, while exploring their inherent dilemmas. The LID BMPs are then introduced to control urban runoff in the context of urban sustainable water systems. After the comprehensive analysis of the various LID BMPs, the advances in LID BMPs research and practice for urban runoff control in China are investigated and summarized. At last, the difficulties of implementing LID BMPs in China are discussed, and a direction for the future is proposed. © 2013 Higher Education Press and Springer-Verlag Berlin Heidelberg.

Yin C.-G.,China Agricultural University | Ma Y.-S.,University of Alberta
Advanced Engineering Informatics | Year: 2012

This paper presents the exploration and application of a feature-based design methodology within mechanical product development cycles. Based on a review of the feature technology and previous research work, this paper focuses on the modeling of intricate relations among features of different design aspects. A concept of feature parameter map that leads to a constraint mapping method is proposed. Further, features are classified into different levels; and information management for product lifecycle support is considered. The application of this method is demonstrated with the conceptual design and optimization of a gearbox as the study case. In addition, an extended feature system for product development was explored. With a spreadsheet package and a computer aided design (CAD) tool, the product model generation, change management and final optimization of the case assembly including its bulk shape, have been achieved. Two important information chains were used to address the aspect of "design for post-manufacture services" with concurrent engineering consideration, i.e. a field installation pattern and a set of wrapping dimensions for product transport packaging. In order to demonstrate the feasibility of change management, a different product derivative model was regenerated by adopting and changing the values of a main conceptual feature. The result is promising. © 2012 Elsevier Ltd. All rights reserved.

Mei Y.,CAS Shanghai Institutes for Biological Sciences | Gao H.-B.,CAS Shanghai Institutes for Biological Sciences | Yuan M.,China Agricultural University | Xue H.-W.,CAS Shanghai Institutes for Biological Sciences
Plant Cell | Year: 2012

Armadillo repeat-containing proteins (ARCPs) are conserved across eukaryotic kingdoms and function in various processes. Regulation of microtubule stability by ARCPs exists widely in mammals and algae, but little is known in plants. Here, we present the functional characterization of an Arabidopsis thaliana ARCP, which was previously identified as Cellulose synthase-interactive protein1 (CSI1), and prove its crucial role in anther and root development. CSI1 is highly expressed in floral tissues, and knockout mutants of CSI1 (three allelic lines) accordingly exhibit defective anther dehiscence, which can be partially rescued by mammalianmicrotubule-stabilizer MAP4, suggesting that CSI1 functions by stabilizing themicrotubular cytoskeleton. CSI1 binds microtubules in vitro, and immunofluorescence and coimmunoprecipitation studies confirmed the physical interactions between CSI1 and microtubules in vivo. Analysis using oryzalin, a microtubule-disrupting drug, further revealed the destabilized microtubules under CSI1 deficiency and confirmed the crucial role of CSI1 in microtubule stability. The dynamic change of CSI1 in response to dehydration strongly suggests the important function of CSI1 in dehydrationinduced microtubule depolymerization and reorganization, which is crucial for anther development. These results indicate the pivotal role of CSI1 in anther development by regulating microtubule stability and hence cell morphogenesis. © 2012 American Society of Plant Biologists. All rights reserved.

Saengwilai P.,Pennsylvania State University | Tian X.,Pennsylvania State University | Tian X.,China Agricultural University | Lynch J.P.,Pennsylvania State University
Plant Physiology | Year: 2014

In developing nations, low soil nitrogen (N) availability is a primary limitation to crop production and food security, while in rich nations, intensive N fertilization is a primary economic, energy, and environmental cost to crop production. It has been proposed that genetic variation for root architectural and anatomical traits enhancing the exploitation of deep soil strata could be deployed to develop crops with greater N acquisition. Here, we provide evidence that maize (Zea mays) genotypes with few crown roots (crown root number [CN]) have greater N acquisition from low-N soils. Maize genotypes differed in their CN response to N limitation in greenhouse mesocosms and in the field. Low-CN genotypes had 45% greater rooting depth in low-N soils than high-CN genotypes. Deep injection of 15N-labeled nitrate showed that low-CN genotypes under low-N conditions acquired more N from deep soil strata than high-CN genotypes, resulting in greater photosynthesis and plant N content. Under low N, low-CN genotypes had greater biomass than high-CN genotypes at flowering (85% in the field study in the United States and 25% in South Africa). In the field in the United States, 1.83 variation in CN was associated with 1.83 variation in yield reduction by N limitation. Our results indicate that CN deserves consideration as a potential trait for genetic improvement of N acquisition from low-N soils. © 2014 American Society of Plant Biologists. All rights reserved.

Du Z.,Tongji University | Fei T.,Dana-Farber Cancer Institute | Fei T.,Harvard University | Verhaak R.G.W.,Anderson University, South Carolina | And 6 more authors.
Nature Structural and Molecular Biology | Year: 2013

Despite growing appreciation of the importance of long noncoding RNAs (lncRNAs) in normal physiology and disease, our knowledge of cancer-related lncRNAs remains limited. By repurposing microarray probes, we constructed expression profiles of 10,207 lncRNA genes in approximately 1,300 tumors over four different cancer types. Through integrative analysis of the lncRNA expression profiles with clinical outcome and somatic copy-number alterations, we identified lncRNAs that are associated with cancer subtypes and clinical prognosis and predicted those that are potential drivers of cancer progression. We validated our predictions by experimentally confirming prostate cancer cell growth dependence on two newly identified lncRNAs. Our analysis provides a resource of clinically relevant lncRNAs for the development of lncRNA biomarkers and the identification of lncRNA therapeutic targets. It also demonstrates the power of integrating publically available genomic data sets and clinical information for discovering disease-associated lncRNAs.

Sun W.,University of Wisconsin - Madison | Sun W.,China Agricultural University | Cao Y.,University of Wisconsin - Madison | Labby K.J.,University of Wisconsin - Madison | And 4 more authors.
Plant Cell | Year: 2012

FLAGELLIN SENSING2 (FLS2) is a transmembrane receptor kinase that activates antimicrobial defense responses upon binding of bacterial flagellin or the flagellin-derived peptide flg22. We find that some Arabidopsis thaliana FLS2 is present in FLS2-FLS2 complexes before and after plant exposure to flg22. flg22 binding capability is not required for FLS2-FLS2 association. Cys pairs flank the extracellular leucine rich repeat (LRR) domain in FLS2 and many other LRR receptors, and we find that the Cys pair N-terminal to the FLS2 LRR is required for normal processing, stability, and function, possibly due to undescribed endoplasmic reticulum quality control mechanisms. By contrast, disruption of the membrane-proximal Cys pair does not block FLS2 function, instead increasing responsiveness to flg22, as indicated by a stronger oxidative burst. There was no evidence for intermolecular FLS2-FLS2 disulfide bridges. Truncated FLS2 containing only the intracellular domain associates with full-length FLS2 and exerts a dominant-negative effect on wild-type FLS2 function that is dependent on expression level but independent of the protein kinase capacity of the truncated protein. FLS2 is insensitive to disruption of multiple N-glycosylation sites, in contrast with the related receptor EF-Tu RECEPTOR that can be rendered nonfunctional by disruption of single glycosylation sites. These and additional findings more precisely define the molecular mechanisms of FLS2 receptor function. © 2012 American Society of Plant Biologists. All rights reserved.

Chen X.,China Agricultural University
China Agricultural Economic Review | Year: 2010

Purpose - China's economic and social structure are changing quickly since the start of the new century and how to balance the urban-rural development has become a key point of the further development of the whole economy. Based on a brief review of rural policies since the new century, the paper aims to investigate whether these policies are successful and discusses what the government should do next as well as how to improve the reform and development of rural economy. Design/methodology/approach - The paper reviews the framework of China's rural policy since 2000 in the first section. Then, the impact of the financial crisis on rural development is analyzed. In the third section, this paper discusses the new issues of current rural reform and development. Findings - The current rural polices are successful and have improved rural economic and social development greatly in the past six years. However, new problems have appeared such as insufficient funds for rural public services, inefficiency of agricultural subsidies, and unfair treatment of rural migrant workers and so on. The impact of the financial crisis on rural development is not as bad as anticipated. Originality/value - The paper reviews the main policies of China's agriculture and rural development and points out the new issues during the rural reform. The impact of the financial crisis on rural development is discussed also. The paper's findings are very important for future policy making. © Emerald Group Publishing Limited.

Wu H.,Huazhong Agricultural University | Wang F.,Huazhong Agricultural University | Hu S.,Zhejiang University | Yin C.,Huazhong Agricultural University | And 4 more authors.
Cellular Signalling | Year: 2012

Autophagy is an evolutionarily conserved process responsible for degradation and recycling of cytoplasmic components through the lysosomal machinery. It has been proved to play pivotal roles in cellular homeostasis, cell growth and organism development. Moreover, abnormalities of autophagy have been linked to numerous human pathophysiologies. Emerging evidence has linked leucine deprivation induced protein breakdown to autophagy, but the underlying mechanisms controlling autophagic activity in this process are not fully understood. Here, we demonstrate that two members of the miR-17 microRNA family, miR-20a and miR-106b, may participate in regulating leucine deprivation induced autophagy via suppression of ULK1 expression in C2C12 myoblasts. We showed that leucine deprivation downregulated miR-20a and miR-106b expression via suppression of their transcription factor c-Myc. We discovered the essential autophagy gene ULK1 as cellular target of miR-20a and miR-106b. Treatment of C2C12 cells with the miR-20a or miR-106b mimic decreased the endogenous ULK1 protein levels. Dual luciferase reporter assay confirmed that the miRNA binding sequences in the 3' UTR of ULK1 contribute to the modulation of ULK1 expression by miR-20a and miR-106b. Furthermore, inhibition of ULK1 expression by the miR-20a or miR-106b mimic blunted activation of autophagy induced by leucine deprivation, while suppression of endogenous miR-20a or miR-106b by specific antagomir in C2C12 cells showed normal autophagic activity. Altogether, our data demonstrated that miR-20a and miR-106b regulated autophagy induced by leucine deprivation in C2C12 cells via targeting ULK1. © 2012 Elsevier Inc.

Xue H.,China Agricultural University | Xue H.,University of Connecticut | Zhang P.,University of Connecticut
IEEE Transactions on Power Delivery | Year: 2012

A high-resolution method for harmonic and interharmonic measurements in power systems is proposed based on the concepts of subspace and least mean square. A subspace function is constructed by using the noise eigenvectors of the autocorrelation matrix of the test signal. The harmonic and interharmonic frequencies of the signal are derived by finding the zeros of the subspace function. A least mean square approach is introduced to compute the amplitudes and phase angles of harmonic and interharmonic components based on the computed frequencies and time-domain measurements of the signal. The proposed method is compared with some of the recently proposed harmonic/interharmonic analysis methods, including discrete Fourier transform (DFT), windowed interpolation DFT, Prony, iterative DFT, and min-norm methods. The effects of noise, fundamental frequency deviation, and subharmonics have been considered. Numerical results show that the proposed method can perform accurate harmonic/interharmonic measurements for power system signals. © 2012 IEEE.

Rong Y.,Tsinghua University | Liu M.,Tsinghua University | Ma L.,Tsinghua University | Du W.,Tsinghua University | And 10 more authors.
Nature Cell Biology | Year: 2012

Autophagy is a lysosome-based degradation pathway. During autophagy, lysosomes fuse with autophagosomes to form autolysosomes. Following starvation-induced autophagy, nascent lysosomes are formed from autolysosomal membranes through an evolutionarily conserved cellular process, autophagic lysosome reformation (ALR), which is critical for maintaining lysosome homeostasis. Here we report that clathrin and phosphatidylinositol-4,5- bisphosphate (PtdIns(4,5)P2) regulate ALR. Combining a screen of candidates identified through proteomic analysis of purified ALR tubules, and large-scale RNAi knockdown, we unveiled a tightly regulated molecular pathway that controls lysosome homeostasis, in which clathrin and PtdIns(4,5)P 2 are the central components. Our functional study demonstrates the central role of clathrin and its associated proteins in cargo sorting, phospholipid conversion, initiation of autolysosome tubulation, and proto-lysosome budding during ALR. Our data not only uncover a molecular pathway by which lysosome homeostasis is maintained through the ALR process, but also reveal unexpected functions of clathrin and PtdIns(4,5)P2 in lysosome homeostasis. © 2012 Macmillan Publishers Limited. All rights reserved.

Zhao G.,China Agricultural University
Biochimica et Biophysica Acta - General Subjects | Year: 2010

Background: Plant and animal ferritins stem from a common ancestor, but plant ferritins exhibit various features that are different from those of animal ferritins. Phytoferritin is observed in plastids (e.g., chloroplasts in leaves, amyloplasts in tubers and seeds), whereas animal ferritin is largely found in the cytoplasm. The main difference in structure between plant and animal ferritins is the two specific domains (TP and EP) at the N-terminal sequence of phytoferritin, which endow phytoferritin with specific iron chemistry. As a member of the nonheme iron group of dietary iron sources, phytoferritin consists of 24 subunits that assemble into a spherical shell storing up to ~2000 Fe3+ in the form of an iron oxyhydroxide-phosphate mineral. This feature is distinct from small molecule nonheme iron existing in cereals, which has poor bioavailability. Scope of review: This review focuses on the relationship between structure and function of phytoferritin and the recent progress in the use of phytoferritin as iron supplement. Major conclusions: Phytoferritin, especially from legume seeds, represents a novel alternative dietary iron source. General significance: An understanding of the chemistry and biology of phytoferritin, its interaction with iron, and its stability against gastric digestion is beneficial to design diets that will be used for treatment of global iron deficiency. © 2010 Elsevier B.V.

Bi D.,China Agricultural University | Bi D.,China National Institute of Biological Sciences | Cheng Y.T.,University of British Columbia | Li X.,University of British Columbia | Zhang Y.,China National Institute of Biological Sciences
Plant Physiology | Year: 2010

Arabidopsis (Arabidopsis thaliana) suppressor of npr1-1, constitutive1 (snc1) contains a gain-of-function mutation in a Toll/interleukin receptor-nucleotide binding site-leucine-rich repeat Resistance (R) protein and it has been a useful tool for dissecting R-protein-mediated immunity. Here we report the identification and characterization of snc4-1D, a semidominant mutant with snc1-like phenotypes. snc4-1D constitutively expresses defense marker genes PR1, PR2, and PDF1.2, and displays enhanced pathogen resistance. Map-based cloning of SNC4 revealed that it encodes an atypical receptor-like kinase with two predicted extracellular glycerophosphoryl diester phosphodiesterase domains. The snc4-1D mutation changes an alanine to threonine in the predicted cytoplasmic kinase domain. Wild-type plants transformed with the mutant snc4-1D gene displayed similar phenotypes as snc4-1D, suggesting that the mutation is a gain-of-function mutation. Epistasis analysis showed that NON-RACE-SPECIFIC DISEASE RESISTANCE1 is required for the snc4-1D mutant phenotypes. In addition, the snc4-1D mutant phenotypes are partially suppressed by knocking out MAP KINASE SUBSTRATE1, a positive defense regulator associated with MAP KINASE4. Furthermore, both the morphology and constitutive pathogen resistance of snc4-1D are partially suppressed by blocking jasmonic acid synthesis, suggesting that jasmonic acid plays an important role in snc4-1D-mediated resistance. Identification of snc4-1D provides us a unique genetic system for analyzing the signal transduction pathways downstream of receptor-like kinases. © 2010 American Society of Plant Biologi.

Zheng B.,China Agricultural University | Zheng B.,University of Pennsylvania | Jia T.,University of Pennsylvania | Walsh P.J.,University of Pennsylvania
Organic Letters | Year: 2013

A direct and efficient approach for palladium-catalyzed arylation of aryl and alkyl methyl sulfones with aryl bromides has been developed. The catalytic system affords arylated sulfones in good to excellent yields (73-90%). © 2013 American Chemical Society.

Liu C.,Beijing Union University | Chen B.,China Agricultural University
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2014

The parameters such as the length, the number of ear rows, and the quantity of kernels in an ear of corn were measured during corn breeding and quality studies. It is usually done mainly manually. This research proposes an efficient image processing algorithm to detect the parameters of an ear of corn based on a machine vision. An experimental device was designed to detect the parameters. It mainly included a computer, a module of data acquisition and control, a stepper motor, a stepper motor driver, a PC camera, and other mechanical components. The computer was used to control the stepper motor to rotate the ear of corn and trigger the PC camera to capture images. The image was segmented after the ear of corn was captured. Its contour was traced. The length and the width of it were obtained by measuring the contour. The horizontal and vertical accumulated pixel values histograms were used in this research. One point in the upper edge and one point in the lower edge of the central ear row were found by first searching for the concaves of the horizontal accumulated pixel values histogram in a specified region. All the points in the upper and the lower edges of the central row were obtained by searching for the concaves of the horizontal accumulated pixel values histograms in a specified moving region which moved following the edge of the central ear row direction. So the image of this central ear row was determined. Each gap between the adjacent kernels could be distinguished by searching for the concaves of the vertical accumulated pixel values histogram in the image area of the central ear row. Then the width of the central ear row and the quantity of kernels in this ear row were recorded. The image of the next adjacent ear row was taken while this ear row was rotated to the location in which the former ear row was imaged. The condition of stopping detection was judged by matching the image of the current ear row with the first. So the number of the ear rows was determined. The quantity of the kernels in this ear of corn could be obtained by accumulating the kernels of all ear rows. In this research, an experimental device was designed to detect the parameters of an ear of corn. And an algorithm was supplied on the base of a machine vision for the same purpose. The image of each ear row in the ear of corn was effectively taken with no repeat. The parameters were detected such as the length and the width of the ear of corn, the width of one ear row, the number of ear rows, and the quantity of kernels in the ear of corn. Experiments showed that the measurement accuracy of the length, the width, and the number of the ear rows of the ear of corn was up to 98%. The measurement accuracy of the width of each ear row and the quantity of kernels was up to 95%. The detection speed was about 102 seconds per ear of corn.

Xu S.,Chinese Institute of Scientific and Technical Information | An X.,Beijing Forestry University | Qiao X.,Chinese Institute of Scientific and Technical Information | Zhu L.,Chinese Institute of Scientific and Technical Information | Li L.,China Agricultural University
Pattern Recognition Letters | Year: 2013

Multi-output regression aims at learning a mapping from a multivariate input feature space to a multivariate output space. Despite its potential usefulness, the standard formulation of the least-squares support vector regression machine (LS-SVR) cannot cope with the multi-output case. The usual procedure is to train multiple independent LS-SVR, thus disregarding the underlying (potentially nonlinear) cross relatedness among different outputs. To address this problem, inspired by the multi-task learning methods, this study proposes a novel approach, Multi-output LS-SVR (MLS-SVR), in multi-output setting. Furthermore, a more efficient training algorithm is also given. Finally, extensive experimental results validate the effectiveness of the proposed approach. © 2013 Elsevier Ltd. All rights reserved.

Brondum R.F.,University of Aarhus | Ma P.,University of Aarhus | Ma P.,China Agricultural University | Lund M.S.,University of Aarhus | Su G.,University of Aarhus
Journal of Dairy Science | Year: 2012

This study investigated the accuracies of imputation from 50K genotypes to high-density genotypes for animals from the Danish, Swedish, or Finnish Red dairy cattle populations, using either a national, combined Red, or combined Red and Holstein reference population. Combining the Red populations increased the imputation accuracy for all 3 populations compared with using single-nationality references. Including Holstein animals in the reference further increased the imputation accuracy for Danish Red. © 2012 American Dairy Science Association.

Cao G.,Nanjing University of Information Science and Technology | Cao G.,Shanghai University of Finance and Economics | Cao J.,Nanjing University of Information Science and Technology | Xu L.,Shanghai University of Finance and Economics | He L.,China Agricultural University
Physica A: Statistical Mechanics and its Applications | Year: 2014

We propose a new method called the multifractal asymmetric detrended cross-correlation analysis method (MF-ADCCA) to investigate the asymmetric cross-correlations in nonstationary time series that combine the multifractal detrended cross-correlation analysis (MF-DCCA) and asymmetric detrended fluctuation analysis (A-DFA). The study aims to determine whether different scaling properties of the cross-correlations are obtained if a one-time series trending is either positive or negative. We apply MF-ADCCA to analyze empirically the scaling behavior of the cross-correlations among the Chinese stock market, the RMB exchange market, and the US stock market. Empirical results indicate that the cross-correlations between the Chinese stock market and the RMB/USD exchange market are more persistent when any one of the markets is falling. On the contrary, the cross-correlations between the Chinese stock market and the RMB/EU, RMB/GBP, RMB/JPY exchange markets and the US stock market are more persistent when one of the markets is rising. Moreover, asymmetric cross-correlations between any two of the selected financial markets are multifractal. © 2013 Elsevier B.V. All rights reserved.

Chai L.,Beijing Academy of Agriculture and Forestry Sciences | Ma C.,China Agricultural University
Nongye Jixie Xuebao/Transactions of the Chinese Society of Agricultural Machinery | Year: 2012

The heating test was conducted in a glass-covering multi-span greenhouse (756 m 2) with groundwater-style GSHP technology. The heat quantity estimating models based on air enthalpy difference method (AEDM) were developed according to the heating characteristics of GSHP. The economical performance and carbon footprint (greenhouse gas emission level) of the GSHP was analyzed and compared with currently widely used coal fired heating system (CFHs)and natural gas fired heating system (GFHs) based on investigated various energy sources price during heating tests. According to the compared results, the GSHPs heating cost is higher than CFHs, but lower than GFHs. Meanwhile, GSHPs CO 2 emission during heating is higher than GFHs, but lower than CFHs.

Bai L.,Jilin University | Wang Z.,Jilin University | Shao Y.-H.,Zhejiang University of Technology | Deng N.-Y.,China Agricultural University
Knowledge-Based Systems | Year: 2014

Both support vector machine (SVM) and twin support vector machine (TWSVM) are powerful classification tools. However, in contrast to many SVM-based feature selection methods, TWSVM has not any corresponding one due to its different mechanism up to now. In this paper, we propose a feature selection method based on TWSVM, called FTSVM. It is interesting because of the advantages of TWSVM in many cases. Our FTSVM is quite different from the SVM-based feature selection methods. In fact, linear SVM constructs a single separating hyperplane which corresponds a single weight for each feature, whereas linear TWSVM constructs two fitting hyperplanes which corresponds to two weights for each feature. In our linear FTSVM, in order to link these two fitting hyperplanes, a feature selection matrix is introduced. Thus, the feature selection becomes to find an optimal matrix, leading to solve a multi-objective mixed-integer programming problem by a greedy algorithm. In addition, the linear FTSVM has been extended to the nonlinear case. Furthermore, a feature ranking strategy based on FTSVM is also suggested. The experimental results on several public available benchmark datasets indicate that our FTSVM not only gives nice feature selection on both linear and nonlinear cases but also improves the performance of TWSVM efficiently. © 2014 Elsevier B.V. All rights reserved.

Gao Y.,China Agricultural University
Pramana - Journal of Physics | Year: 2012

By generalizing the complex potential approach developed by Lekhnitskii, plane problems of one-dimensional quasicrystals are solved ?rst by using an octet formalism for which there are four pairs of complex roots. The approach uses a representation of stresses and proceeds by integration of the expressions for deformations and application of the anisotropic constitutive law and the compatibility of displacements. To illustrate its utility, the generalized Lekhnitskii's formalism is used to analyse the coupled phonon and phason ?elds in an in?nite quasicrystal medium containing an elliptic rigid inclusion. © Indian Academy of Sciences.

Deol P.,North Carolina State University | Heitman J.,North Carolina State University | Amoozegar A.,North Carolina State University | Ren T.,China Agricultural University | Horton R.,Iowa State University
Water Resources Research | Year: 2012

Accurate quantification of energy and mass transfer during soil water evaporation is critical for improving understanding of the hydrologic cycle and for many environmental, agricultural, and engineering applications. Drying of soil under radiation boundary conditions results in formation of a dry surface layer (DSL), which is accompanied by a shift in the position of the latent heat sink from the surface to the subsurface. Detailed investigation of evaporative dynamics within this active near-surface zone has mostly been limited to modeling, with few measurements available to test models. Soil column studies were conducted to quantify nonisothermal subsurface evaporation profiles using a sensible heat balance (SHB) approach. Eleven-needle heat pulse probes were used to measure soil temperature and thermal property distributions at the millimeter scale in the near-surface soil. Depth-integrated SHB evaporation rates were compared with mass balance evaporation estimates under controlled laboratory conditions. The results show that the SHB method effectively measured total subsurface evaporation rates with only 0.01-0.03 mm h-1 difference from mass balance estimates. The SHB approach also quantified millimeter-scale nonisothermal subsurface evaporation profiles over a drying event, which has not been previously possible. Thickness of the DSL was also examined using measured soil thermal conductivity distributions near the drying surface. Estimates of the DSL thickness were consistent with observed evaporation profile distributions from SHB. Estimated thickness of the DSL was further used to compute diffusive vapor flux. The diffusive vapor flux also closely matched both mass balance evaporation rates and subsurface evaporation rates estimated from SHB. © 2012. American Geophysical Union. All Rights Reserved.

Liu X.,China Agricultural University | Winterton S.L.,California State Collection of Arthropods
PLoS ONE | Year: 2016

The taxonomy of Megaloptera from the Nearctic region is fairly well known and their faunal diversity has been largely surveyed, even in relatively remote regions. However, the evolutionary history of Nearctic Megaloptera is still poorly known with phylogenetic and biogeographic studies lacking. In this paper, we report a new fishfly species of the endemic North American genus Neohermes Banks, 1908, increasing the total number known of species to six. This new species (Neohermes inexpectatus sp. nov.) is currently known to occur only in California (USA) and is apparently confined to the Northern Coastal Range. The new species resembles the three Neohermes species from eastern North America based on the relatively small body size and the presence of female gonostyli 9. However, our phylogenetic analysis using adult morphological data recovered the new species as the sister species to the remaining Neohermes, which includes two species from western North America and three from eastern North America. According to the present interspecific phylogeny of Neohermes, with reconstructed ancestral areas, the initial divergence within the genus was found to take place in western North America, with a subsequent eastward dispersal. This likely lead to the modern distribution of Neohermes in eastern North America with the closure of the Mid-Continental Seaway, which separated western and eastern North America in the Mid-Late Cretaceous (100-80 MYA) and finally disappeared at the end of the Cretaceous (70 MYA). The uplift of the Cordilleran System probably accounted for the divergence between the eastern and two western Neohermes species. This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.

Bernstein H.,China Agricultural University
Journal of Peasant Studies | Year: 2016

This paper provides a selective survey of food regimes and food regime analysis since the seminal article by Harriet Friedmann and Philip McMichael in 1989, and further traced through their subsequent (individual) work. It identifies eight key elements or dimensions of food regime analysis, namely the international state system; international divisions of labour and patterns of trade; the ‘rules’ and discursive (ideological) legitimations of different food regimes; relations between agriculture and industry, including technical and environmental change in farming; dominant forms of capital and their modalities of accumulation; social forces (other than capitals and states); the tensions and contradictions of specific food regimes; and transitions between food regimes. These are used to summarise three food regimes in the history of world capitalism to date: a first regime from 1870 to 1914, a second regime from 1945 to 1973, and a third corporate food regime from the 1980s proposed by McMichael within the period of neoliberal globalisation. Questions of theory, method and evidence are noted in the course of the exposition and pulled together in a final section which criticises the ‘peasant turn’ of the ‘corporate food regime’ and the analytical and empirical weaknesses associated with it. © 2016 Informa UK Limited, trading as Taylor & Francis Group.

Hao X.,China Agricultural University | Thelen K.,Michigan State University | Gao J.,Nanjing University
Biosystems Engineering | Year: 2012

The primary objective was to investigate the potential of using dry-grind maize spectral data for predicting ethanol yield, as well as to identity important wavelengths related to ethanol yield production. Spectral data from 222 ground maize grain samples were obtained over the spectral region of 400-2498 nm in 2 nm intervals. Thirty replicate runs were conducted, and for each run, 166 out of 222 samples were randomly selected for calibration, and the remaining 56 samples were used for validation. Partial least square regressions (PLSRs) were conducted on the complete spectra and on the wavelengths selected by bootstrapping based on the computed variable importance for projection values (Boot_VIP). Models with the wavelengths selected by the Boot_VIP and models with the complete spectra had similar prediction capabilities in the independent validation, with the average root mean square error of prediction (RMSEP) of 0.56%, which is comparable to the standard deviation of the dry fermentation reference method. The Boot_VIP procedure selected wavelengths consistently in 30 replicate runs, averaging 109 wavelengths selected at each run, and there were 101 wavelengths selected for all 30 runs. The selected wavelengths concentrated on 400-550 nm of the visible region and 2300-2360 nm of the NIR region. The first two factors from the Boot_VIP models were almost identical to the respective first two factors from models with the complete spectra. © 2012 IAgrE.

Joo Y.-H.,Hanwha Corporation | Gao H.,China Agricultural University | Parrish D.A.,U.S. Navy | Cho S.G.,Agency for Defense Development | And 2 more authors.
Journal of Materials Chemistry | Year: 2012

2-(5-Nitroiminotetrazol-1-yl)acetic acid (4) was synthesized from 100% nitric acid and ethyl 2-(5-aminotetrazol-1-yl)acetate (2), which was easily obtained by reaction of ethyl aminoacetate hydrochloride, sodium hydroxide, and cyanogen azide. Compound 4 was also formed with 100% nitric acid and 2-(5-aminotetrazol-1-yl)acetic acid which was prepared from sodium 5-aminotetrazolate and 2-chloroacetic acid. New energetic materials comprised of nitroiminotetrazolate salts with nitroiminotetrazolate and carboxylate anions have been characterized spectroscopically as well as with single crystal X-ray diffraction and elemental analyses. In addition, the heats of formation (ΔH f), and detonation pressures (P) and velocities (D) were calculated. All compounds were insensitive (>40 J) for impact with BAM Fallhammer. This journal is © The Royal Society of Chemistry 2012.

Zhao L.,CAS Institute of Genetics and Developmental Biology | Wang D.,CAS Institute of Genetics and Developmental Biology | Wang D.,China Agricultural University | Wang Q.,CAS Institute of Genetics and Developmental Biology | And 2 more authors.
PLoS Genetics | Year: 2013

The formation of synapses and the proper construction of neural circuits depend on signaling pathways that regulate cytoskeletal structure and dynamics. After the mutual recognition of a growing axon and its target, multiple signaling pathways are activated that regulate cytoskeletal dynamics to determine the morphology and strength of the connection. By analyzing Drosophila mutations in the cytoplasmic FMRP interacting protein Cyfip, we demonstrate that this component of the WAVE complex inhibits the assembly of filamentous actin (F-actin) and thereby regulates key aspects of synaptogenesis. Cyfip regulates the distribution of F-actin filaments in presynaptic neuromuscular junction (NMJ) terminals. At cyfip mutant NMJs, F-actin assembly was accelerated, resulting in shorter NMJs, more numerous satellite boutons, and reduced quantal content. Increased synaptic vesicle size and failure to maintain excitatory junctional potential amplitudes under high-frequency stimulation in cyfip mutants indicated an endocytic defect. cyfip mutants exhibited upregulated bone morphogenetic protein (BMP) signaling, a major growth-promoting pathway known to be attenuated by endocytosis at the Drosophila NMJ. We propose that Cyfip regulates synapse development and endocytosis by inhibiting actin assembly. © 2013 Zhao et al.

Roberts M.,University of North Carolina at Chapel Hill | Tang S.,China Agricultural University | Stallmann A.,University of North Carolina at Chapel Hill | Dangl J.L.,University of North Carolina at Chapel Hill | Bonardi V.,University of North Carolina at Chapel Hill
PLoS Genetics | Year: 2013

Plants react to pathogen attack via recognition of, and response to, pathogen-specific molecules at the cell surface and inside the cell. Pathogen effectors (virulence factors) are monitored by intracellular nucleotide-binding leucine-rich repeat (NB-LRR) sensor proteins in plants and mammals. Here, we study the genetic requirements for defense responses of an autoactive mutant of ADR1-L2, an Arabidopsis coiled-coil (CC)-NB-LRR protein. ADR1-L2 functions upstream of salicylic acid (SA) accumulation in several defense contexts, and it can act in this context as a "helper" to transduce specific microbial activation signals from "sensor" NB-LRRs. This helper activity does not require an intact P-loop. ADR1-L2 and another of two closely related members of this small NB-LRR family are also required for propagation of unregulated runaway cell death (rcd) in an lsd1 mutant. We demonstrate here that, in this particular context, ADR1-L2 function is P-loop dependent. We generated an autoactive missense mutation, ADR1-L2D484V, in a small homology motif termed MHD. Expression of ADR1-L2D848V leads to dwarfed plants that exhibit increased disease resistance and constitutively high SA levels. The morphological phenotype also requires an intact P-loop, suggesting that these ADR1-L2D484V phenotypes reflect canonical activation of this NB-LRR protein. We used ADR1-L2D484V to define genetic requirements for signaling. Signaling from ADR1-L2D484V does not require NADPH oxidase and is negatively regulated by EDS1 and AtMC1. Transcriptional regulation of ADR1-L2D484V is correlated with its phenotypic outputs; these outputs are both SA-dependent and -independent. The genetic requirements for ADR1-L2D484V activity resemble those that regulate an SA-gradient-dependent signal amplification of defense and cell death signaling initially observed in the absence of LSD1. Importantly, ADR1-L2D484V autoactivation signaling is controlled by both EDS1 and SA in separable, but linked pathways. These data allows us to propose a genetic model that provides insight into an SA-dependent feedback regulation loop, which, surprisingly, includes ADR1-L2. © 2013 Roberts et al.

Wang X.-J.,China Agricultural University
Acta Virologica | Year: 2011

Literature pertaining to the interactions between Marek's disease virus (MDV) entry-related glycoproteins and corresponding receptors is still limited. Results from a Western blot analysis of cellular proteins for virus receptors and co-immunoprecipitation suggest that heat shock protein 70 (HSP70) is a potential cellular receptor for MDV glycoprotein gH. Plaque inhibition assays confirm the involvement of HSP70 in the early stages of MDV entry into chicken embryo fibroblasts (CEF). The present work supports that HSP70 is implicated in the MDV entry process by binding to gH, and enhances the understanding of multifunctional HSP70 and the MDV infection process.

Wang Y.,China Agricultural University | Wang Y.,Childrens Nutrition Research Center | Guan X.,Childrens Nutrition Research Center | Guan X.,Baylor College of Medicine
American Journal of Physiology - Endocrinology and Metabolism | Year: 2010

Glucagon-like peptide-2 (GLP-2) is a neuropeptide secreted from endocrine cells in the gut and neurons in the brain. GLP-2 stimulates intestinal crypt cell proliferation and mucosal blood flow while decreasing gastric emptying and gut motility. However, a GLP-2-mediated signaling network has not been fully established in primary cells. Since the GLP-2 receptor mRNA and protein were highly expressed in the mouse hippocampus, we further characterized that human 125I-labeled GLP-2 1-33 specifically bound to cultured hippocampal neurons with Kd = 0.48 nM, and GLP-2 acutely induced subcellular translocalization of the early gene c-Fos. Using the whole cell patch clamp, we recorded barium currents (I Ba) flowing through voltage-gated Ca 2+ channels (VGCC) in those neurons in the presence of GLP-2 with and without inhibitors. We showed that GLP-2 (20 nM) enhanced the whole cell I Ba mediated by L-type VGCC that was defined using an L-type Ca 2+ channel blocker (nifedipine, 10 μM). Moreover, GLP-2-potentiation of L-type VGCC was abolished in neurons pretreated with a PKA inhibitor (PKI 14- 22, 1 μM). Finally, using a fluorescent nonmetabolized glucose analog (6-NBDG) tracing imaging, we showed that glucose was taken up directly by cultured neurons. GLP-2 increased 2-deoxy-D-[ 3H]glucose uptake that was dependent upon dosage, activation of PKA, and potentiation of L-type VGCC. We conclude that GLP-2 potentiates L-type VGCC activity through activating PKA signaling, partially stimulating glucose uptake by primary cultured hippocampal neurons. The potentiation of L-type VGCC may be physiologically relevant to GLP-2-induced neuroendocrine modulation of neurotransmitter release and hormone secretion. Copyright © 2010 the American Physiological Society.

Wang F.,Chinese Academy of Forestry | Pan X.,Chinese Academy of Inspection and Quarantine | Wang D.,Chinese Academy of Forestry | Shen C.,China Agricultural University | Lu Q.,Chinese Academy of Forestry
Land Use Policy | Year: 2013

China is a developing country plagued by a long-term and large-scale desertification, which causes serious environmental problems. At the same time, China also has a long history of fighting desertification, especially in the recent decades. Thus, we think China's experience and lessons may be very important and useful for other developing countries to promote the degradation mitigation and life improvement. © 2012 Elsevier Ltd.

Wang X.-L.,Shandong Agricultural University | Gao X.-Q.,Shandong Agricultural University | Wang X.-C.,China Agricultural University
Plant, Cell and Environment | Year: 2011

Actin filaments and chloroplasts in guard cells play roles in stomatal function. However, detailed actin dynamics vary, and the roles that they play in chloroplast localization during stomatal movement remain to be determined. We examined the dynamics of actin filaments and chloroplast localization in transgenic tobacco expressing green fluorescent protein (GFP)-mouse talin in guard cells by time-lapse imaging. Actin filaments showed sliding, bundling and branching dynamics in moving guard cells. During stomatal movement, long filaments can be severed into small fragments, which can form longer filaments by end-joining activities. With chloroplast movement, actin filaments near chloroplasts showed severing and elongation activity in guard cells during stomatal movement. Cytochalasin B treatment abolished elongation, bundling and branching activities of actin filaments in guard cells, and these changes of actin filaments, and as a result, more chloroplasts were localized at the centre of guard cells. However, chloroplast turning to avoid high light, and sliding of actin fragments near the chloroplast, was unaffected following cytochalasin B treatment in guard cells. We suggest that the sliding dynamics of actin may play roles in chloroplast turning in guard cells. Our results indicate that the stochastic dynamics of actin filaments in guard cells regulate chloroplast localization during stomatal movement. © 2011 Blackwell Publishing Ltd.

Zhu J.,Pennsylvania State University | Zhang C.,Pennsylvania State University | Zhang C.,China Agricultural University | Lynch J.P.,Pennsylvania State University
Functional Plant Biology | Year: 2010

Root hairs are subcellular protrusions from the root epidermis that are important for the acquisition of immobile nutrients such as phosphorus (P). Genetic variation exists for both root hair length and the plasticity of root hair length in response to P availability, where plasticity manifests as increased root hair length in response to low P availability. Although it is known that long root hairs assist P acquisition, the utility of phenotypic plasticity for this trait is not known. To assess the utility of root hair plasticity for adaptation to low phosphorus availability, we evaluated six recombinant inbred lines of maize (Zea mays L.) with varying root hair lengths and root hair plasticity in a controlled environment and in the field. Genotypes with long root hairs under low P availability had significantly greater plant growth, P uptake, specific P absorption rates and lower metabolic cost-benefit ratios than short-haired genotypes. Root hair length had no direct effect on root respiration. In the controlled environment, plastic genotypes had greater biomass allocation to roots, greater reduction in specific root respiration and greater final biomass accumulation at low phosphorus availability than constitutively long-haired genotypes. In the field study, the growth of plastic and long-haired genotypes were comparable under low P, but both were superior to short-haired genotypes. We propose that root hair plasticity is a component of a broader suite of traits, including plasticity in root respiration, that permit greater root growth and phosphorus acquisition in low P soils. © 2010 CSIRO.

Schultzhaus Z.,Texas A&M University | Yan H.,China Agricultural University | Shaw B.D.,Texas A&M University
Molecular Microbiology | Year: 2015

Endocytosis and exocytosis are strictly segregated at the ends of hyphal cells of filamentous fungi, with a collar of endocytic activity encircling the growing cell tip, which elongates through directed membrane fusion. It has been proposed that this separation supports an endocytic recycling pathway that maintains polar localization of proteins at the growing apex. In a search for proteins in the filamentous fungus Aspergillus nidulans that possess an NPFxD motif, which signals for endocytosis, a Type 4 P-Type ATPase was identified and named DnfA. Interestingly, NPFxD is at a different region of DnfA than the same motif in the Saccharomyces cerevisiae ortholog, although endocytosis is dependent on this motif for both proteins. DnfA is involved in asexual sporulation and polarized growth. Additionally, it is segregated within the Spitzenkörper from another Type 4 P-type ATPase, DnfB. Next, the phosphatidylserine marker GFP::Lact-C2 was expressed in growing hyphae, which revealed that this phospholipid is enriched on the cytosolic face of secretory vesicles. This distribution is affected by deleting either dnfA or dnfB. These findings provide evidence for the spatial and temporal segregation of Type4-ATPases in filamentous fungi, and the asymmetric distribution of phosphatidylserine to the Spitzenkörper in A.nidulans. © 2015 John Wiley & Sons Ltd.

Zhang Z.,Texas A&M University | Liu X.,CAS Institute of Genetics and Developmental Biology | Guo X.,Texas A&M University | Guo X.,China Agricultural University | And 2 more authors.
Nature Plants | Year: 2016

Argonaute (AGO) proteins recruit 21.24-nucleotide (nt) small RNAs (sRNAs) to constitute RNA-induced silencing complexes (RISCs) to regulate gene expression at transcriptional or posttranscriptional levels1.3. Arabidopsis encodes nine functional AGO proteins. These proteins are classified into three clusters, AGO1/5/10, AGO2/3/7 and AGO4/6/9, based on their sequence similarity, functional redundancy, as well as species and features of AGO-bound sRNAs4.7. Although most Arabidopsis AGO proteins have been studied well, AGO3- bound sRNAs and their basic function remain unknown. Here we observed that AGO3 could not complement the signature function of AGO2, the closest genetic paralog of AGO3, in host antiviral defence. We also found, surprisingly, that AGO3 predominantly bound 24-nt sRNAs with 5′-terminal adenine. The spectrum of AGO3-associated sRNAs was different from those bound to AGO2, further indicating their functional divergence. By contrast, approximately 30% of AGO3-bound 24-nt sRNAs overlapped with those bound to AGO4, and over 60% of AGO3-associated 24-nt sRNAenriched loci were identical to those of AGO4. Moreover, the redundancy of AGO3- and AGO4-bound sRNAs is much more than that of AGO6- and AGO4-recruited sRNAs. In addition, expression of AGO3 driven by the AGO4 promoter partially complemented AGO4 function and rescued a DNA methylation defect in the ago4-1 background. Together, our results indicated that AGO3, similarly to AGO4, is a component in the epigenetic pathway. © 2016 Macmillan Publishers Limited. All rights reserved.

Qiu J.,Tsinghua University | Li F.-F.,China Agricultural University
Journal of Microscopy | Year: 2014

Microscopic images of curvilinear fibre network structure like cytoskeleton are traditionally analysed by qualitative observation, which can hardly provide quantitative information of their morphological properties. However, such information is crucially contributive to the understanding of important biological events, even helps to learn about the inner relations hard to perceive. Individual fibre segmentation-based curvilinear structure detector proposed in this study can identify each individual fibre in the network, as well as connections between different fibres. Quantitative information of each individual fibre, including length, orientation and position, can be extracted; so are the connecting modes in the fibre network, such as bifurcation, intersection and overlap. Distribution of fibres with different morphological properties is also presented. No manual intervening or subjective judging is required in the analysing process. Both synthesized and experimental microscopic images have verified that the detector is capable to segment curvilinear network at the subcellular level with strong noise immunity. The proposed detector is finally applied to the morphological study on cytoskeleton. It is believed that the individual fibre segmentation-based curvilinear structure detector can greatly enhance our understanding of those biological images generated from tons of biological experiments. © 2014 Royal Microscopical Society.

Shao Y.-H.,Zhejiang University of Technology | Wang Z.,Jilin University | Chen W.-J.,Zhejiang University of Technology | Deng N.-Y.,China Agricultural University
Applied Intelligence | Year: 2013

In this paper, we propose a novel least squares twin parametric-margin support vector machine (TPMSVM) for binary classification, called LSTPMSVM for short. LSTPMSVM attempts to solve two modified primal problems of TPMSVM, instead of two dual problems usually solved. The solution of the two modified primal problems reduces to solving just two systems of linear equations as opposed to solving two quadratic programming problems along with two systems of linear equations in TPMSVM, which leads to extremely simple and fast algorithm. Classification using nonlinear kernel with reduced technique also leads to systems of linear equations. Therefore our LSTPMSVM is able to solve large datasets accurately without any external optimizers. Further, a particle swarm optimization (PSO) algorithm is introduced to do the parameter selection. Our experiments on synthetic as well as on several benchmark data sets indicate that our LSTPMSVM has comparable classification accuracy to that of TPMSVM but with remarkably less computational time. © 2013 Springer Science+Business Media New York.

Wu B.M.,China Agricultural University | Subbarao K.V.,University of California at Davis
Phytopathology | Year: 2014

Verticillium wilt, caused by Verticillium dahliae, is a destructive disease in lettuce, and the pathogen is seedborne. Even though maximum seed infestation rates of <5% have been detected in commercial lettuce seed lots, it is necessary to establish acceptable contamination thresholds to prevent introduction and establishment of the pathogen in lettuce production fields. However, introduction of inoculum into lettuce fields for experimental purposes to determine its long term effects is undesirable. Therefore, we constructed a simulation model to study the spread of Verticillium wilt following pathogen introduction from seed. The model consists of four components: the first for simulating infection of host plants, the second for simulating reproduction of microsclerotia on diseased plants, the third for simulating the survival of microsclerotia, and the fourth for simulating the dispersal of microsclerotia. The simulation results demonstrated that the inoculum density-disease incidence curve parameters and the dispersal gradients affect disease spread in the field. Although a steep dispersal gradient facilitated the establishment of the disease in a new field with a low inoculum density, a long-tail gradient allowed microsclerotia to be dispersed over greater distances, promoting the disease spread in fields with high inoculum density. The simulation results also revealed the importance of avoiding successive lettuce crops in the same field, reducing survival rate of microsclerotia between crops, and the need for breeding resistance against V. dahliae in lettuce cultivars to lower the number of microsclerotia formed on each diseased plant. The simulation results, however, suggested that, even with a low seed infestation rate, the pathogen would eventually become established if susceptible lettuce cultivars were grown consecutively in the same field for many years. A threshold for seed infestation can be established only when two of the three drivers of the disease-(i) low microsclerotia production per diseased plant, (ii) long-tail dispersal gradient, and (iii) low microsclerotia survival between lettuce crops-are present. © 2014 The American Phytopathological Society.

Dai X.,Chinese Academy of Sciences | Huo Z.,China Agricultural University | Wang H.,Chinese Academy of Sciences
Field Crops Research | Year: 2011

In saline fields, irrigation management often requires understanding crop responses to soil moisture and salt content. Developing models for evaluating the effects of soil moisture and salinity on crop yield is important to the application of irrigation practices in saline soil. Artificial neural network (ANN) and multi-linear regression (MLR) models respectively with 10 (ANN-10, MLR-10) and 6 (ANN-6, MLR-6) input variables, including soil moisture and salinity at crop different growth stages, were developed to simulate the response of sunflower yield to soil moisture and salinity. A connection weight method is used to understand crop sensitivity to soil moisture and salt stress of different growth stages. Compared with MLRs, both ANN models have higher precision with RMSEs of 1.1 and 1.6tha-1, REs of 12.0% and 17.3%, and R2 of 0.84 and 0.80, for ANN-10 and ANN-6, respectively. The sunflower sensitivity to soil salinity varied with the different soil salinity ranges. For low and medium saline soils, sunflower yield was more sensitive at crop squaring stage, but for high saline soil at seedling stage. High soil moisture content could compensate the yield decrease resulting from salt stress regardless of salt levels at the crop sowing stage. The response of sunflower yield to soil moisture at different stages in saline soils can be understood through the simulated results of ANN-6. Overall, the ANN models are useful for investigating and understanding the relationship between crop yield and soil moisture and salinity at different crop growth stages. © 2011 Elsevier B.V.

Xu Y.,China Agricultural University | Luo D.,Chongqing Geomatics Center | Peng J.,Central University of Costa Rica
Journal of Geographical Sciences | Year: 2011

Due to the extremely poor soil cover, a low soil-forming rate, and inappropriate intensive land use, soil erosion is a serious problem in Guizhou Province, which is located in the centre of the karst areas of Southwest China. In order to bring soil erosion under control and restore environment, the Chinese Government has initiated a serious of ecological rehabilitation projects such as the Grain-for-Green Programme and Natural Forest Protection Program and brought about tremendous influences on land-use change and soil erosion in Guizhou Province. This paper explored the relationship between land use and soil erosion in the Maotiao River watershed, a typical agricultural area with severe soil erosion in central Guizhou Province. In this study, we analyzed the spatio-temporal dynamic change of land-use type in Maotiao River watershed from 1973 to 2007 using Landsat MSS image in 1973, Landsat TM data in 1990 and 2007. Soil erosion change characteristics from 1973 to 2007, and soil loss among different land-use types were examined by integrating the Revised Universal Soil Loss Equation (RUSLE) with a GIS environment. The results indicate that changes in land use within the watershed have significantly affected soil erosion. From 1973 to 1990, dry farmland and rocky desertified land significantly increased. In contrast, shrubby land, other forestland and grassland significantly decreased, which caused accelerated soil erosion in the study area. This trend was reversed from 1990 to 2007 with an increased area of land-use types for ecological use owing to the implementation of environmental protection programs. Soil erosion also significantly varied among land-use types. Erosion was most serious in dry farmland and the lightest in paddy field. Dry farmland with a gradient of 6°-25° was the major contributor to soil erosion, and conservation practices should be taken in these areas. The results of this study provide useful information for decision makers and planners to take sustainable land use management and soil conservation measures in the area. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.

Lu Y.,Huazhong Agricultural University | Yuan M.,Huazhong Agricultural University | Gao X.,China Agricultural University | Kang T.,Huazhong Agricultural University | And 3 more authors.
PLoS ONE | Year: 2013

Reverse transcription quantitative polymerase chain reaction (qRT-PCR) has rapidly become the most sensitive and accurate method for the quantification of gene expression. To facilitate gene expression studies and obtain more accurate qRT-PCR data, normalization relative to stable housekeeping genes is required. These housekeeping genes need to show stable expression under the given experimental conditions for the qRT-PCR results to be accurate. Unfortunately, there are no studies on the stability of housekeeping genes used in Spodoptera litura. In this study, eight candidate reference genes, elongation factor 1 alpha (EF1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), ribosomal protein L10 (RPL10), ribosomal protein S3 (RPS3), beta actin (ACTB), beta FTZ-F1 (FTZF1), ubiquinol-cytochrome c reductase (UCCR), and arginine kinase (AK), were evaluated for their suitability as normalization genes under different experimental conditions using the statistical software programs, BestKeeper, geNorm and Normfinder, and the comparative ΔCt method. We determined the expression levels of the candidate reference genes for three biotic factors (developmental stage, tissue and population), and four abiotic treatments (temperature, insecticide, food and starvation). The results indicated that the best sets of candidates as reference genes were as follows: GAPDH and UCCR for developmental stages; RPL10, AK and EF1 for different tissues; RPL10 and EF1 for different populations in China; GAPDH and EF1 for temperature-stressed larvae; AK and ACTB for larvae treated with different insecticides; RPL10, GAPDH and UCCR for larvae fed different diets; RPS3 and ACTB for starved larvae. We believe that these results make an important contribution to gene analysis studies in S. litura and form the basis of further research on stable reference genes in S. litura and other organisms. © 2013 Lu et al.

Liu X.-Z.,Ludong University | Wang G.,China Agricultural University
Rapid Communications in Mass Spectrometry | Year: 2010

The natural abundances of stable nitrogen isotopes in plants and soils have been viewed as recorders that can be used to reconstruct paleoclimate and ecological processes or to indicate the biogeochemical cycle of nitrogen in nature. This study systematically measured the nitrogen isotope composition (δ15N) in plants and surface soils along an altitudinal transect of elevation range of 1200 to 4500m on the eastern slope of Mount Gongga in southwest China. The influences of photosynthetic pathways on plant d15N as well as the effects of temperature and precipitation on d15N altitudinal trends in plants and surface soils are discussed. Across this altitude transect, the d15N values of C3 and C4 plants on Mount Gongga range between-9.87% and 7.58% with a mean value of-1.33%, and between-3.98% and 4.38% with a mean value of-0.25%, respectively. There is an evident δ15N difference between C3 plants and C4 plants. If, however, you only compare C4 plants with those C3 plants growing at the same altitudinal range, no significant difference in δ15N exists between them, suggesting that photosynthetic pathway does not have an influence on the plant δ15N values. In addition, we found that C3, C4 plants and surface soil (0-5 cm depth) all trend significantly towards more negative δ15N with increasing elevation. Furthermore, this study shows that the mean annual temperature and the mean annual precipitation positively and negatively correlate with δ15N in C3 and C4 plants, respectively. This indicates that precipitation and temperature are the main controlling factors of the δ15N variation in plants with altitude. We propose that lower δ15N values of plants and soils at higher altitude should be attributed to lower mineralization and lower net nitrification rates induced by low temperature and abundant rainfall. © 2010 John Wiley & Sons, Ltd.

Wang J.,China Agricultural University | Wang E.,CSIRO | Liu D.L.,Wagga Wagga Agricultural Institute
Theoretical and Applied Climatology | Year: 2011

The study used a modelling approach to assess the potential impacts of likely climate change and increase in CO2 concentration on the wheat growth and water balance in Murray-Darling Basin in Australia. Impacts of individual changes in temperature, rainfall or CO2 concentration as, well as the 2050 and 2070 climate change scenarios, were analysed. Along an E-W transect, wheat yield at western sites (warmer and drier) was simulated to be more sensitive to temperature increase than that at eastern sites; along the S-N transect, wheat yield at northern warmer sites was simulated to be more sensitive to temperature increase, within 1-3°C temperature increase. Along the E-W and S-N transects, wheat at drier sites would benefit more from elevated [CO2] than at wetter sites, but more sensitive to the decline in rainfall. The increase in temperature only did not have much impact on water balance. Elevated [CO2] increased the drainage in all the sites, whilst rainfall reduction decreased evapotranspiration, runoff and drainage, especially at drier sites. In 2050, wheat yield would increase by 1-10% under all climate change scenarios along the S-N transect, except for the northernmost site (Dalby). Along the E-W transect, the most obvious increase of wheat yields under all climate change scenarios occurred in cooler and wetter eastern sites