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91.
The Euclidean position and orientation of a wheeled mobile robot (WMR) is typically required for autonomous selection and control of agricultural operations in a greenhouse. A vision-based localization scheme is formulated as a desire to identify the position and orientation of a WMR navigating in a greenhouse by utilizing the image feedback of the above-the-aisle targets from an on-board camera. An innovative daisy chaining strategy is used to find the local coordinates of the above-the-aisle targets in order to localize a WMR. In contrast to typical camera configurations used for vision-based control problems, the localization scheme in this paper is developed using a moving on-board camera viewing reseeding targets. Multi-view photogrammetric methods are used to develop relationships between different camera frames and WMR coordinate systems. Experimental results demonstrate the feasibility of the developed geometric model.  相似文献   
92.
A field experiment was conducted to evaluate the response of chickpea, Cicer arietinum cv. GG 2 to cobalt sulfate and cobalt chloride at 0, 100, 200, 400, 800 and 1,600?g ha?1. At three leaf stage chickpea seedlings were fertigated with both cobalt sources and levels. Both cobalt sources at the higher level (400 to 1,600?g ha?1) were found injurious to chickpea. All growth, yield, and quality parameters were adversely affected by cobalt sulfate at every level; however, cobalt chloride has given appreciable result up to 100 and 200?g ha?1 over no application of cobalt. Cobalt content in plant and soil increased linearly with increases in cobalt concentration, which reduced chickpea yield linearly. Cobalt sulfate was apparently more harmful than cobalt chloride. The study suggests cobalt chloride has not shown any toxicity up to 100?g ha?1 and can be used for higher productivity of chickpea.  相似文献   
93.
Of the wheat grown in North-West India the majority is consumed as traditional Indian flat bread (chapatti). Chapatti quality is important to consumers and people are willing to pay more for better quality wheat flour, but farmers do not specifically target quality outcomes as the majority of their wheat is sold with no segregation. For farmers the main objective is to harvest maximum yields, but in the last decade productivity growth for wheat yields has slowed in the areas where the wheat is grown in a double cropping pattern. Nutrient depletion and temperature-related stress are possible causes for this decline in productivity growth. Farmers meanwhile are looking to opportunities to maintain profitability and, with consumers willing to pay a higher price for better chapatti wheat, an opportunity exists for farmers to manage their wheat to improve both the yield as well as quality of wheat. In this paper we evaluate management practices that best achieve high yield and better chapatti quality, and assess the temperature environment for the winter wheat growing season. A step-wise analysis of the long-term temperature trend for sites in NW India showed that mean annual temperature has increased by 0.7-1.0 °C during the last decade. Field experiments with wheat varieties (C-306, WH-283, DBW-17, PBW-343, PBW-502, PBW-550, Raj-3765 and WH-1025) were conducted at farmers’ fields under 4 different sequential cropping rotations for the 2007-08 and 2008-09 winter seasons in Haryana (India). C-306 and WH-283 are varieties with excellent chapatti quality but are lower yielding by 15-26% than the more widely grown varieties such as PBW-343 and PBW-502. The replicated experiments involved three sowing times, these being an early sowing (late October to early November, timely sowing (mid November) and a late sowing (early December). A differential response of varieties was observed to sowing time with the yield of C-306 better whereas that of WH-283 and Raj-3765 was poor in early sown conditions. The varieties DBW-17, PBW-343 and PBW-502 were the highest yielding wheat with similar performance under early as well as timely sowing. All the varieties had lowest yield in December sowing. In general, late sowing had lower thousand grain weight but higher protein content. Of the quality measure grain hardness was the only attribute with a consistent positive correlation with chapatti quality. The chapatti score was higher for varieties C-306 and WH-283 compared to the other varieties but grain hardness and chapatti score was not much affected by sowing time. With all varieties included in the analysis there was no correlation between protein and chapatti score, but within an individual variety usually higher protein resulted in a higher chapatti score. There was no association of grain test weight or sedimentation value with chapatti score. From the results shown here it is evident that farmers will be able to manage with variety choice and timely sowing to obtain chapatti quality without losing grain yield benefits.  相似文献   
94.
通过破坏性抽样、相片网格法和落叶采受器法,获得了印度Shoolpaneshwar野生动物禁猎区内生长的柚木和印度实竹叶面积指数。建立了一个异速生长方程来决定两个树种的叶面积指数。结果表明,异速生长方程获得的叶面积指数与破坏性抽样、相片网格法和落叶采受器法评估得到的指数值相近;2种测定方式下,柚木的均方根误差分别是0.90和1.15,印度实竹的均方根误差分别为0.38和0.46。估计的和计算获得的叶面积指数值匹配性较好,说明用建立的方程计算得到的2个树种叶面积指数的准确性较好。总之,冠幅伸展是一个估计树木叶面积较好的且敏感的参数。本文所提出的方程可以用作估计热带柚木和印度实竹叶面积指数。图4表1参22。  相似文献   
95.
Organophosphate (OP) pesticides are among the most widely used synthetic chemicals for controlling a wide variety of pests. Chlorpyrifos (o,o′-diethyl-o-3,5,6-trichloro-2-pyridyl phosphorothionate, CPF) is among the leading OP pesticides used extensively throughout the world including India while methyl parathion (o,o-di methyl-o-p-nitrophenyl phosphorothioate, MPT) another OP compound, widely used as insecticide and acaricide to control many biting or sucking pests of agricultural crops. Present study was carried out to compare the chronic toxicity of CPF and MPT, their potential to generate oxidative stress and ameliorating effects of antioxidant vitamins in brain of rats. Results of the present study clearly demonstrated that the oral exposure of CPF or MPT, generated oxidative stress in different parts of rat brain consequently accumulating malondialdehyde (MDA) and 4-hydroxynonanal (4HNE), the two major end products of lipid peroxidation, in all the three brain regions i.e. fore-, mid- and hind-brain. The levels of hydrogen peroxide (H2O2) were also increased in all the three brain regions when compared with control. CPF and MPT exposure caused decrease in the levels of reduced glutathione (GSH) and increase in the levels of oxidized glutathione (GSSG) in all the three brain regions. The increase in the levels of MDA, 4HNE, H2O2 and GSSG was less pronounced when CPF or MPT was given to the rats fed with a mixture of vitamin A, E and C. The present findings clearly show that oral intake of a mixture of vitamin A, E and C protects the rats from MPT or CPF induced oxidative stress and suggest that this treatment alleviates the toxicity of these pesticides to a greater extent.  相似文献   
96.
Resource-poor farmers in India cultivate upland rice as a subsistence crop in poor soil with minimum inputs, often applying little or no fertilizer and controlling weeds by hand. Consequently, upland rice yields are very low. In our study, the response to management intensification of fertilizer application at rates of 40 N ha−1, 13 P ha−1, and 16.7 K ha−1 and two weed control treatments as compared with no fertilizer, and one hand weeding practice commonly followed by farmers in rainfed upland areas was examined with a large set of advanced breeding lines and adapted upland varieties tested over 3 years in multi-location trials. Highly significant genotype × environment interaction was observed in combined analyses across environments, leading to sub-grouping of sites into the high-yielding or favorable and low-yielding or unfavorable upland environment groups. A significant effect of management regime was observed. Averaged over 15 environments, the moderate-input treatment out-yielded the low-input treatment by nearly 65% or 0.8 t ha−1 under favorable environments and by nearly 48% (0.3 t ha−1) in unfavorable environments. A significant genotype effect and genotype × input management interaction for yield at favorable sites was observed. However, the same was not significant at unfavorable sites. Varietal differences were relatively small at unfavorable sites across input levels. The heritability estimates for grain yield were moderately high in both moderate- and low-input conditions in favorable environments. The genetic correlation between yields in moderate- and low-input conditions was high in both favorable and unfavorable environments. The study indicated that improved varieties performed well relative to landraces under low-input management. Improved varieties along with modestly intensified management offer an attractive option to increase the productivity of rainfed upland environments. For both favorable and unfavorable environments, indirect selection under moderate-input conditions was less efficient than direct selection for grain yield in low-input conditions, indicating upland breeding programs to adopt selection for grain yield under both moderate- and low-input conditions.  相似文献   
97.
98.
In order to provide normal morphological data and reference values for fibre type proportions, against which changes due to facial nerve paralysis or primary facial muscle myopathies can be compared, a histological and histochemical study was carried out on the buccinator muscle of clinically normal adult dogs. Using myosin adenosine triphosphatase under acidic pre-incubation (pH 4.3) conditions, three histochemical fibre types--1, 2A and 2C were recognised. There was no significant difference in mean diameter between left- and right-sided buccinator muscle samples for type 1 versus 2. Mean diameters of fibre types were: type 1, 27.02 +/- 6.61 microns and type 2, 29.05 +/- 7.75 microns. The histographical distribution of fibre type diameters was unimodal. The buccinator muscle had a type 2 fibre predominance with a mean type 1 to type 2 ratio of 32:68. The number of fibres with internal nuclei was less than or equal to 1 per cent, atrophy-hypertrophy factors typically were less than or equal to 200, and variability coefficients approximated 250. Muscle spindles were not observed in any muscle sample.  相似文献   
99.
Serial peripheral nerve biopsies from two golden retriever littermates with chronic neurologic disease were taken for morphologic and morphometric evaluation. Teased nerve preparations were difficult to interpret due to the lightness of myelin staining. Light and electron microscopic findings were characterized by the following: reduced number of myelinated axons, presence of myelinated sheaths inappropriately thin for the caliber of the fiber, poor myelin compaction, increased numbers of Schwann cell nuclei, increased concentration of neurofilaments in myelinated axons, many Schwann cells with voluminous cytoplasm, and increased perineurial collagen. Onion bulb formation was not seen. In contrast to control data, a poor correlation was seen between numbers of myelin lamellae (ML) and axonal circumference (AC). The frequency distribution of ML ranged from 5 to 55 lamellae in affected animals (mean, 28 lamellae) compared to 20 to 140 lamellae in controls (mean, 66 lamellae). The ML/AC ratio was significantly reduced (P less than 0.001) in nerves of affected dogs. Morphometric results indicated that fibers of all calibers were hypomyelinated.  相似文献   
100.
A morphologic and morphometric study was carried out on the facial nerve: to determine normal histologic data in myelinated fibers of clinically normal young adult dogs; to establish reference values for mean fiber diameter, and to delineate the relative diameter frequency distribution curve. Few degenerative changes were observed in single teased-nerve fibers and semithin cross-sectional nerve preparations. Statistical difference was not observed between left and right facial nerves. The distribution of fiber diameters in the facial nerve was unimodal. Mean (+/- SD) fiber diameter of the facial nerve was 3.92 +/- 1.18 microns. Approximately 89% of fibers in the facial nerve had diameter between 3 and 6 microns. Fiber diameter ranged from 2 to 12 microns; however, less than 1% of fibers had diameter greater than 8 microns.  相似文献   
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