Optimal vision-based guidance row locating for autonomous agricultural machines

Precision Agriculture - With the rapid advances in precision agriculture technology, machine vision is emerging as a means to obtain accurate spatial information for a control system at relatively...     

基于互联网的温室控制系统开发(摘选)

该研究旨在设计一种基于互联网的温室控制系统,以便实现远程监测和控制。所设计的系统包括硬件(传感器、单片机、交换机、电脑、网络摄像头和执行器)和软件(采集和控制)。通过将执行器(风机、泵、喷雾器、机械遮光装置和可旋转摄像头)安装在试验温室并且连接到计算机互联网上对系统性能进行测试。在水培生菜等整个生长期内对其微气候参数进行监测,在3种操作模式(手动、自动和定时)下,对温度、湿度、光照和含水率进行控制。利用开关对风机、泵和喷雾器进行控制以确保微气候参数能保持在所需范围内。机械遮阴和摄头旋转采用伺服电机驱动,由PWM信号驱动进行控制。对3种模式下系统的性能进行评价和比较。结果表明,对温度、湿度、光照和含水率4个参数可以通过互联网Remote Desktop完成远程控制。监控单元提供的植物生长图片可作为制定控制决策的附加信息。     

Renal and biochemical changes produced in broilers by high-protein, high-calcium, urea-containing, and vitamin-A-deficient diets

Three hundred 18-day-old male chicks (Arbor Acre) were divided into five groups of 60 each and given high-protein (42.28%), high-calcium (3.37%), urea-containing (5%), vitamin-A-deficient, or control diets to study the effect of nutritional imbalances on the development of nephritis and related biochemical changes over 15 weeks. The first four diets increased the levels of glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, uric acid, and nonprotein nitrogen in serum. Blood urea was increased by only the urea diet. Hypoglycemia and a decrease in hepatic glucose-6-phosphatase were also observed in chicks fed the first four diets. The vitamin-A-deficient diet resulted in a depletion of vitamin A in the liver and kidneys. These changes were directly correlated with the prolonged feeding of experimental diets and also with the severity of nephritis and degenerative changes in various organs. It was concluded that increasing the intake of nitrogen or calcium in order to increase production may in fact have the opposite effect, leading to degenerative changes in various tissues and to nephritis.     

Application of low altitude remote sensing (LARS) platform for monitoring crop growth and weed infestation in a soybean plantation

Crop growth and weed infestation in a soybean field were monitored by processing low altitude remote sensing (LARS) images taken from crane-mounted and unmanned radio controlled helicopter-mounted platforms. Images were taken for comparison between true color (R?CG?CB) and color-infrared (NIR) digital cameras acquired at different heights above ground. All LARS images were processed to estimate vegetation-indices for distinguishing stages of crop growth and estimating weed density. LARS images from the two platforms (low-dynamic and high-dynamic) were evaluated. It was found that crane-mounted RGBC and NIRC platforms resulted in better quality images at lower altitudes (<10?m). This makes the crane-mounted platform an attractive option in terms of specific low altitude applications at an inexpensive cost. Helicopter-mounted RGBH and NIRH images were found suitable at altitudes >10?m. Comparison of NDVIC and NDVIH images showed that NDVI values at 28 DAG (days after germination) exhibited a strong relationship with altitudes used to capture images (R ² of 0.75 for NDVIC and 0.79 for NDVIH). However, high altitudes (>10?m) decreased NDVI values for both systems. Higher R ² values (??0.7) were also obtained between indices estimated from crane-and helicopter-mounted images with those obtained using an on-ground spectrometer, which showed an adequate suitability of the proposed LARS platform systems for crop growth and weed infestation detection. Further, chlorophyll content was well correlated with the indices from these images with high R ² values (>0.75) for 7, 14, 21 and 28 DAG.     

Anatrichosoma sp. in the footpads of a cat: Diagnosis and pathology of Namibian case

Anatrichosoma species are an unusual group of zoonotic trichuroid nematodes. Due to limited knowledge of their life cycle and diagnostic challenges, anatrichosomiasis has been reported only 3 times in domestic animals. A short-haired cat from central Windhoek, Namibia, presented with ulceration, swelling, and sepsis on all four paws, a severe generalized lymphadenopathy and considerable invasive eosinophilia. Histological analysis revealed epidermal hyperplasia, with severe serocellular crusting on the skin surface. One specimen revealed a series of thick-walled eggs within nematode segments with a few sections containing eggs with bioperculate appearance which is compatible with the Aphasmid group of nematodes, more specifically, the genus Anatrichosoma. Ivermectin treatment completely cleared the condition. This is the first report of Anatrichosoma sp. in the Republic of Namibia, identified from a unique location in the capital, Windhoek.     

Rejuvenation influences indirect organogenesis from leaf explants of Pomegranate (Punica granatum L.) ‘Kandhari Kabuli’

Sequential subculturing leads to a gradual physiological change in cells that may be termed ‘rejuvenation’. The effect of repetitive subculturing on callus induction and shoot regeneration from leaf explants of Punica granatum L. ‘Kandhari Kabuli’ were investigated. Surface-sterilised leaves were cultured on 1.0× Murashige and Skoog (MS) medium supplemented with 4.0 mg l^–1 α-naphthaleneacetic acid (NAA) and 2.0 mg l^–1 6-benzyladenine (BA) for callus induction. Shoots were regenerated from callus on 1.0× MS medium supplemented with 1.5 mg l^–1 BA, 0.5 mg l^–1 kinetin, and 0.25 mg l^–1 NAA. Subculturing of callus onto fresh medium maintained the rate of shoot formation and substantially increased the production of shoot buds up to the second subculture. Following further subculture passages, a lower shoot regeneration potential from callus was observed. A maximum shoot bud induction from callus of 63.9% was observed at the second subculture passage. The rate of multiplication of in vitro shoots increased until the fourth subculture, then became constant. Similarly, in vitro rooting of micro-shoots increased up to the third subculture, followed by a decline during further subculturing.