共查询到18条相似文献，搜索用时 171 毫秒
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红颈苇鹀育雏行为及雏鸟发育观察 总被引：1，自引：0，他引：1
在吉林省西部首见红颈苇鹀繁殖和育雏行为,填补了历史上该区域无繁殖的记录。观察发现,茂密的植被和陈旧的草簇构成了红颈苇鹀繁殖的要件;红颈苇巫鸟的育雏行为有明确分工,雌鸟履行孵化职责,而雄鸟则负责安全警戒,孵化期约15 d,育雏期约16 d;全天喂雏行为有差别,从清晨到上午8:00时、从下午18:00时到日落为喂食高峰期,雄鸟喂食雏鸟的次数高于雌鸟;红颈苇鹀以草籽和谷物为食,繁殖季节主要捕食昆虫;50 d左右,幼鸟完全可以自食其力。 相似文献
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于2015～2017年的3年间在小五台山自然保护区分别对褐马鸡的家鸡代孵及育雏进行了初步研究。结果表明:整个孵化期为28.3 d,大致分为初期(1～10 d)、中期(11～21 d)、后期(22～28 d)。其受精率为64%,孵化率为50.3%。孵化的平均温度为37.37℃,平均湿度为60.63%,凉蛋平均温度为23.33℃。育雏采用室内自然育雏与室外自然育雏相结合的方法进行。室内自然育雏的平均密度为0.1～0.2只/m~2,喂食为用温水泡软不定量的小米、2颗熟鸡蛋黄/d、只,10～15 g黄粉虫和蚁卵,以后逐渐增加,饮水为1/1000的青霉素温开水,室内自然育雏期为18 d;室外自然育雏的平均密度为0.05～0.1只/m~2,喂食为雏鸡饲料、绿叶蔬菜、一定量黄粉虫和蚁卵,饮水为1/1000的青霉素温开水,室外自然育雏期为50～65 d。 相似文献
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Soichi Tanaka Yuko Fujiwara Yoshihisa Fujii Shogo Okumura Hiroyoshi Togo Naoya Kukutsu Shoji Mochizuki 《Journal of Wood Science》2013,59(5):367-374
To evaluate the dielectric anisotropy caused by wood structure at a millimeter wave frequency of 100 GHz, the dielectric parameters for flat-sawn specimens of nine wood species at 0 and 11 % moisture content (MC) were measured using a free space method devised for reducing the multiple reflections under an electric field of millimeter waves parallel to longitudinal and tangential directions of wood, and those in radial direction were estimated using a conventional approximation theory. The dielectric parameters in the tangential and radial directions were almost identical and constantly smaller than those in the longitudinal direction. All the dielectric parameters increased with wood density and were larger at 11 than 0 % MC. The dielectric parameters in the longitudinal and transverse directions and the dielectric anisotropy between them were well fitted to the regression lines based on a dielectric mixture model composed of pores and dielectric isotropic wood substance, and a parallel capacitor and Lichtenecker’s exponential formulas were employed to represent the dielectric parameters of the mixture in the longitudinal and transverse directions, respectively. It was concluded that the dielectric anisotropy at 100 GHz is caused by the pore alignment and that the dielectric parameters are almost unaffected by anatomical structures, such as the rays. It was also confirmed that the free space method was effective for the measurement of the dielectric parameters for the flat-sawn specimens. 相似文献
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种子介电分选技术研究新进展 总被引：10，自引：0，他引：10
本文讨论了植物种子的电场、磁场效应,肯定了电磁场处理对种子生理生化指标的正效应,它能提高种子活力和发芽率,增大发芽势;对国内外种子介电分选装置与设备的现状和发展作了介绍和分析;对介电分选机理作了进一步的探讨,提出了区别于传统分选技术的关键因素是电极化力。在分析分选电场的构成及计算方法的同时,对作为分选介质的种子在电场中的状态、介电性质以及影响因素作了说明,指出影响种子介电性质的主要因素是种子含水率 相似文献
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Stavros Avramidis Lazaros Iliadis Shawn D. Mansfield 《Wood Science and Technology》2006,40(7):563-574
An artificial neural network that can predict the dielectric properties of wood was developed and tested with experimental data. The network was capable of accurately predicting the loss factor of two wood species not only as a function of ambient electro-thermal conditions but also as a function of basic wood chemistry. This way, an important predictive tool is created that allows optimization of dielectric heating and drying for many wood species without significant experimentation should their chemical composition be known under variable temperatures, moisture contents and electric filed characteristics. 相似文献
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The attenuation coefficients of 100-GHz millimeter waves polarized linearly were measured for cross-cut, quarter-sawn, and
flat-sawn boards of hinoki (Chamaecyparis obtusa) that were 0.2–2.0 cm thick. This was done to examine the applicability of free-wave propagation theory for applying electromagnetic
waves to wood. It was found that the transmittance of a millimeter wave through the specimen boards was lower when the fiber
direction of a board was parallel to the direction of the electric field of the incident wave than when the fiber direction
was perpendicular to the electric field, and there was little difference in the transmittance between the tangential and radial
directions for the former case. These findings can be quantitatively explained by using propagation theory and the dielectric
properties of wood. 相似文献
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Onyango Irene Awino Robert Skilton Shadrack Muya Samuel Kabochi Hellen Kutima Muo Kasina 《East African Agricultural and Forestry Journal》2017,82(1):23-35
Varroa mite (Varroa destructor Anderson and Trueman) is a major global threat to the western honey bee (Apis mellifera L.). The ectoparasite has been implicated in the spread of honeybee viruses. Beekeeping plays a major role in transmission of the mite. The study aimed at assessing levels of Varroa infestation, bee viruses and bacteria incidences in domesticated honeybee colonies. Samples of adult honey bees, bee brood and Varroa mites were collected from Baringo, Narok, Kwale, Magarini, Voi, Ijara, Busia and Siaya in Kenya. Ten hives in each site were inspected for the presence of Varroa mites on adult bees using the icing sugar technique and forceps in sealed brood cells. The number of mites observed were recorded per site. Ribonucleic acid was extracted from the mites, brood and adult bees and a polymerase chain reaction was performed to detect the black queen cell virus. Pooled RNA samples of brood and adult bees were used in next generation sequencing on a 454 GS FLX platform to detect bee viruses and bacteria. Varroa mites were reported in all the study sites at varying levels. The black queen cell virus and three iflaviruses, European foul brood and its secondary causative agent Enterococcus faecalis were reported. The Kenyan honeybee population is threatened by bee pests and pathogens. There is a need for constant monitoring of bee pests and diseases in honeybee colonies in the country for early detection and to provide data on the status of bee health. All stakeholders in the beekeeping value chain should be enlightened on their role in pest and disease transmission. 相似文献