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Agricultural pesticide use and food safety:California's model

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Journal of Integrative Agriculture 2015年第11期14卷 2340-2357页

作者： Minghua Zhang Michael R Zeiss Shu Geng Department of Land Air and Water ResourcesUniversity of California California Department of Pesticide Regulation Sino-US Joint food Safety Research Center Northwest A&F University Department of Plant Sciences University of California

Pesticides have been an essential part of agriculture to protect crops and livestock from pest infestations and yield reduction for many decades. Despite their usefulness, pesticides could pose potential risks to food safety and the environment as well as human health. This paper reviews the positive benefits of agricultural pesticide use as well as some potential negative impacts on the environment and food safety. In addition, using the case of California, we discuss the need for both residue monitoring and effective pest management to promote food safety. Twenty years＇ pesticide residue data from California＇s pesticide residue monitoring program were analyzed. Results showed that more than 95% of food samples were in compliance with US pesticide residue standards （tolerances）. However, certain commodities from certain sources had high percentages of residues above tolerance levels. Even when residues above tolerance levels were detected, most were at levels well below 1 mg kg^-1, and most posed negligible acute health risk. However, a few detected residues had the potential to cause health effects. Therefore, establishing an effective food residue monitoring program is important to ensure food quality throughout the marketplace.

关键词： food safety food security pesticide use residue monitoring environmental impacts IPM tolerances maximum residue limits (MRLs)

Methods to detect a vian influenza virus for food safety surveillance

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Journal of Integrative Agriculture 2015年第11期14卷 2296-2308页

作者： SHI Ping Shu Geng LI Ting-ting LI Yu-shui fENG Ting WU Hua-nan School of Environment and Energy Peking University Shenzhen Graduate School Sino-US Joint food Safety Research Center Northwest A&F University Department of Plant Science University of California

Avian influenza （AI）, caused by the influenza A virus, has been a global concern for public health. AI outbreaks not only impact the poultry production, but also give rise to a risk in food safety caused by viral contamination of poultry products in the food supply chain. Distinctions in AI outbreak between strains H5N1 and H7N9 indicate that early detection of the AI virus in poultry is crucial for the effective warning and control of AI to ensure food safety. Therefore, the establishment of a poultry surveillance system for food safety by early detection is urgent and critical. In this article, methods to detect AI virus, including current methods recommended by the World Health Organization （WHO） and the World Organisation for Animal Health （Office International des Epizooties, OIE） and novel techniques not commonly used or commercialized are reviewed and evaluated for feasibility of use in the poultry surveillance system. Conventional methods usually applied for the purpose of AI diagnosis face some practical challenges to establishing a comprehensive poultry surveillance program in the poultry supply chain. Diverse development of new technologies can meet the specific requirements of AI virus detection in various stages or scenarios throughout the poultry supply chain where onsite, rapid and ultrasensitive methods are emphasized. Systematic approaches or integrated methods ought to be employed according to the application scenarios at every stage of the poultry supply chain to prevent AI outbreaks.

关键词： avian influenza food safety detection methods poultry supply chain surveillance system

Transient content caching and updating with modified harmony search for Internet of Things

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Digital Communications and Networks 2019年第1期5卷 24-33页

作者： Chao Xu Xijun Wang Key Laboratory of Agricultural Internet of Things Ministry of Agriculuture and Rural Affairs School of Information Engineering Northwest A&F University Yangling Shaanxi China School of Electronics and Communication Engineering Sun Yat-sen University Guangzhou China

Internet of Things (IoT) has emerged as one of the new use cases in the 5th Generation wireless networks. However, the transient nature of the data generated in IoT networks brings great challenges for content caching. In this paper, we study a joint content caching and updating strategy in IoT networks, taking both the energy consumption of the sensors and the freshness loss of the contents into account. In particular, we decide whether or not to cache the transient data and, if so, how often the servers should update their contents. We formulate this content caching and updating problem as a mixed 0–1 integer non-convex optimization programming, and devise a Harmony Search based content Caching and Updating (HSCU) algorithm, which is self-learning and derivativefree and hence stipulates no requirement on the relationship between the objective and variables. finally, extensive simulation results verify the effectiveness of our proposed algorithm in terms of the achieved satisfaction ratio for content delivery, normalized energy consumption, and overall network utility, by comparing it with some baseline algorithms.

关键词： IoT Content caching and updating Data freshness

The Development of a Two-finger Dexterous Bionic Hand with Three Grasping Patterns-NWAfU Hand

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Journal of Bionic Engineering 2020年第4期17卷 718-731页

作者： Zhiguo Li Zhongliang Hou Yuxiao Mao Yan Shang Lukasz Kuta College of Mechanical and Electronic Engineering Northwest A&F UniversityYangling 712100China Key Laboratory of Agricultural Internet of Things Ministry of Agriculture and Rural AffairsYangling 712100China Institute of Environmental Protection and Development Wroclaw University of Environmental and Life SciencesWroclaw 50-375Poland

Bionic inspiration from human thumb and index finger was the drive to design a high-performance two-finger dexterous *** size of each phalanx and the motion range of each joint in the human thumb and index finger were summarized,and the features of three grasping patterns were described in ***,a two-finger dexterous bionic hand with 6 Degrees of freedom(Dofs)was *** the mechanical thumb and index finger were made up of three rigid phalanx links and three mechanical rotation *** grasp-release tests validated that the bionic hand can perform three grasping patterns:power grasp,precision pinch and lateral *** grasping success rates were high under the following cases:(1)when power grasping was used to grasp a ring with external diameter 20 mm-140 mm,a cylinder with massf *** work provided a method for developing two-fimger bionic hand with three grasping patterns,and further revealed the linkage between the difference in fimger structure and size and the hand manipulation dexterity.

关键词： dexterous bionic hand mechanical finger power grasp precision pinch lateral pinch

Model of soybean NDVI change based on time series

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International Journal of Agricultural and Biological Engineering 2014年第5期7卷 64-70页

作者： Zhang Zhitao Yubin Lan Wu Pute Han Wenting College of Water Resources and Architectural Engineering Northwest A&F UniversityYangling 712100China Aerial Application Technology USDA-ARS-SPARC-AATRUCollege StationTX 77845USA Institute of Water Saving Agriculture in Arid Area of China Northwest A&F UniversityYangling 712100China

Normalized Difference Vegetation Index(NDVI)has been found to have good correlations with many physical properties of soybean *** to the factors of air temperature,humidity,solar radiation,soil moisture,etc.,NDVI of soybean varies dynamically in a *** establishment of the soybean NDVI prediction model at different times in a day can effectively modify this *** soybean NDVI values are continuously monitored in hours during soybean seeding,flowering&podding and maturating stages by way of Green *** show that the trend of NDVI change every day in the three stages is taken on as a reverse *** NDVI value reaches to the maximum at 8 am or 9 am and decreases to its minimum at 2 pm before a moderate rise.A model for intraday and long-term NDVI change for soybean is *** test of the model with independent data indicates that the precision meets the demands,with the root mean square error(RMSE)of each day being 3.95,5.45 and 2.86 for the seeding stage,the bean podding stage and the maturation period,*** prediction RMSEs of the soybean NDVI model for soybeans of the three stages for the fifth day are 5.75,2.65 and 5.51,respectively and the prediction RMSEs for the sixth day are 9.74,2.82 and 14.04,respectively according to the data from the first four days.

关键词： model NDVI monitoring time time series atmospheric radiation soybean

带有年龄结构的捕食者-食饵模型研究(英文)

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生物数学学报 2011年第1期26卷 48-56页

作者：郑立飞赵惠燕西北农林科技大学理学院陕西杨凌712100 西北农林科技大学植保学院陕西杨凌712100

研究带有年龄结构的捕食者-食饵模型的渐近行为.本文所研究的模型假定捕食者从幼年阶段到成年阶段的转变率依赖于幼年种群的密度,还假定幼年捕食者捕食食饵.本文最终给出了有年龄结构的捕食者-食饵模型的捕食者持久和灭绝的若干条件.

关键词：年龄结构持久稳定性平衡点

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轻量土击实密度模型与工程特性(英文)

岩土工程学报 2014年第11期36卷 2127-2135页

作者：侯天顺西北农林科技大学水利与建筑工程学院陕西杨凌712100

为了探索软夹杂土体压实机理,指导轻量土配方设计与压实施工,基于混合土物质结构组成及土体压缩变密的物理本质,建立了击实密度模型。试验发现模型预测值与实测湿密度基本一致,绝对误差仅有0.003~0.051 g/cm3,相对误差仅有0.282%~5.267%... 详细信息

为了探索软夹杂土体压实机理,指导轻量土配方设计与压实施工,基于混合土物质结构组成及土体压缩变密的物理本质,建立了击实密度模型。试验发现模型预测值与实测湿密度基本一致,绝对误差仅有0.003~0.051 g/cm3,相对误差仅有0.282%~5.267%,证明击实密度模型可以准确预测混合土不同击实条件下的湿密度。EPS颗粒压缩率、混合土湿密度随击实次数增大而增大,增大趋势逐渐变缓;混合土孔隙比随击实次数增大而减小。在击实作用下,轻量土湿密度的提高是由土体的孔隙减少和EPS颗粒软夹杂的塑性压缩共同完成的。与砂土轻量土性质相似,粘土轻量土的湿密度、无侧限抗压强度随击实次数增大而增大。n=25击时,EPS颗粒压缩率范围6.13%~11.51%;n=94击时,EPS颗粒压缩率范围12.80%~14.87%。证明规范规定的击实次数与击实能量适合混合土的击实,不会导致EPS颗粒消泡。考虑到击实密度模型参数测定非常繁琐,根据工程实际情况,假设压实过程中土料含水量不变与压实后土颗粒-EPS颗粒之间的孔隙近似为0,进一步提出了简化击实密度模型,并且通过试验证明了简化模型完全适用于实际工程。

关键词：轻量土击实密度模型湿密度无侧限抗压强度压缩率击实次数

Predicting wheat kernels’protein content by near infrared hyperspectral imaging

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International Journal of Agricultural and Biological Engineering 2016年第2期9卷 163-170页

作者： Yang Shuqin He Dongjian Ning Jifeng College of Mechanical and Electronic Engineering Northwest A&F UniversityYangling 712100China College of Information Engineering Northwest A&F UniversityYangling 712100China

The objective of this study was to explore the potential of near infrared hyperspectral imaging combined with statistical regression models and neural networks for nondestructive prediction of protein content of wheat ***-nine samples from 11 breeds of wheat kernels were *** protein percentage of each sample measured by semimicro-Kjeldahl method was taken as the reference *** comparing the prediction models of principal components regression(PCR)and partial least squares regression(PLSR)with various pretreatment methods,PLSR preprocessed by zero mean normalization(z score)function of MATLAB was found to obtain better prediction results than other regression *** on 10 latent variables of PLSR,the radial basis function(RBf)neural network was applied to improve the prediction,in which the coefficients of determination(R2)were greater than 0.92 for both the calibration set and validation set,while the corresponding RMSE values were 0.3496 and 0.4005,***,hyperspectral imaging can provide a fast and non-destructive method for predicting the wheat kernels’protein content.

关键词： wheat kernels protein nondestructive prediction near infrared hyperspectral imaging partial least squares regression radial basis function neural network

Impact of Closed Greenhouse on Yield and Water Productivity of four Vegetable Crop Species

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Agricultural Science & Technology 2017年第12期18卷 2606-2611,2616页

作者： qiang fan min zhang yaai dang xuzhang xue college of water resources and architectural engineering northwest a&f universityYangling 712100China college of science northwest a&f universityYangling 712100China national engineering research center for information technology in agriculture Beijing 100097China

Aiming to provide theoretical foundations for crop growth and water control optimization in closed greenhouses, this paper compares the closed greenhouse and the conventional greenhouse in terms of crop growth, yield and irrigation water productivity. The results showed that environmental factors such as temperature, humidity and CO_2 in a closed greenhouse, were far higher than those in a conventional greenhouse. Compared with tomato and cowpea, spinach and alfalfa adapted well to high temperature and high humidity, and their water requirement and water use efficiency in the closed greenhouse were higher than those in the conventional greenhouse.

关键词： Closed greenhouse Water use efficiency Crop growth