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1.
《Journal of dairy science》2021,104(12):12912-12924
The objective of this study was to evaluate the effect of an ultra-diluted complex supplemented as a prophylactic strategy on the incidence risk of diseases, metabolism, and performance of weaned Holstein calves immediately after grouping. Additionally, the objective was to investigate the carryover effects on heifer-raising and first-lactation periods, in a double-blind, placebo-controlled trial. A total of 184 weaned Holstein calves (83 ± 7.9 d of life; 112.5 ± 11.7 kg of body weight; values are mean ± standard deviation) were allocated to 8 paddocks in a completely randomized block design experiment. During a 112-d period, animals received a total mixed ration and were randomly allocated into 2 groups: (1) CON: placebo-control (basal diet + calcium carbonate, top-dressed at 30 g/animal per day of placebo), or (2) UD: ultra-diluted complex (basal diet + TopVita-Real H, top-dressed at 30 g/animal per day of sulfur (10−60) + viola tricolor (10−14) + caladium seguinum (10−30) + zincum oxydatum (10−30) + phosphorus (10−60) + carduus marianus (10−60) + colibacillinum (10−30) + podophyllum (10−30) + vehicle: calcium carbonate; quantum sufficit 1 kg). Incidence risk of diseases, number of days with disease, and mortality events were recorded daily. Performance measurements and blood collection were carried out at enrollment and every 28 d until the end of the study period. The incidence risk of digestive problems was higher for the CON group. Additionally, the CON group had higher cumulative number of days per calf affected by tick-borne disease. Blood analysis revealed that CON calves had increased mean corpuscular hemoglobin amount and concentration than UD calves on d 28 after enrollment and had increased serum albumin and total protein concentration on d 84. Furthermore, higher albumin to globulin ratio was found in CON calves than in those of UD group at enrollment; however, on d 56, the inverse was observed. On d 28 after enrollment, CON calves had increased serum cortisol concentration. Regarding body measurements, higher withers height and body depth were detected in UD calves, on d 28 and d 84, respectively. Finally, higher culling risk was observed in the CON group during the heifer-raising period. In conclusion, a lower incidence risk of digestive problems and days with tick-borne disease were detected in the UD group. Additionally, systemic inflammation was improved by UD complex based on circulating inflammation and stress biomarkers on specific days after enrollment. However, UD product did not improve performance at the post-weaning, heifer-raising, and first-lactation periods.  相似文献   
2.
刘蕾  朱绪胜  申皓 《测控技术》2020,39(11):18-22
针对现有激光跟踪测量系统可视性分析方法在计算效率方面的不足,提出一种基于透视投影的激光跟踪测量系统可视性分析方法。给出了激光跟踪仪可视性分析的数学定义,利用测点与站位点之间的关系对可视性分析进行描述;利用包络盒对障碍物进行简化,同时根据障碍物、测点、站位点之间的关系,剔除了不参与可视性分析运算的障碍物;在此基础上,利用透视投影的原理,对障碍物在跟踪仪可布置平面上的投影进行了求解,并利用该投影与站位点之间是否包含的关系,得到了测点与站位点之间的可视性矩阵,结合提出的可视性势能的概念,对跟踪仪满足可视性的区域进行了求解。最后,以某飞机舱门检验工装的测量为例,验证了该方法和模型的正确性和有效性。  相似文献   
3.
Illumination is essential for modern life as colorful world is perceived by human visionary system. Display technology has been developing rapidly in recent decades, and the basic principle is related to the way that the image is illuminated and light is emanated. Traditional illumination is provided by different types of light sources, and the display image is visible in large viewing space until the emanating light decays to zero. This work proposes and demonstrates a novel illumination scheme for a display in which the displaying images are visible only in specific spatial regions. The directional backlight ensures the image propagating to specific direction while imaging visibility can be controlled to terminate abruptly at certain distance from the display screen while exerting no influence to nearby regions. The working principle for such an illumination scheme is the use of the modulated coherent directional backlight through an axicon lens. It is shown that the illumination scheme can robustly deliver carried image information to the designated viewing region. This new illumination scheme has many advantages over conventional illumination, including its usage for personal display, very lower energy consumption, as well as minimizing light hazard pollution.  相似文献   
4.

Due to limited depth-of-field of digital single-lens reflex cameras, the scene content within a limited distance from the imaging plane remains in focus while other objects closer to or further away from the point of focus appear as blurred (out-of-focus) in the image. Multi-Focus Image Fusion can be used to reconstruct a fully focused image from two or more partially focused images of the same scene. In this paper, a new Fuzzy Based Hybrid Focus Measure (FBHFM) for multi-focus image fusion has been proposed. Optimal block size is very critical step for multi-focus image fusion. Particle Swarm Optimization (PSO) algorithm has been used to find optimal size of the block of the images for extraction of focus measure features. After finding optimal blocks, three focus measures Sum of Modified Laplacian, Gray Level Variance and Contrast Visibility has been extracted and combined these focus measures by using intelligent fuzzy technique. Fuzzy based hybrid intelligent focus values were estimated using contrast visibility measure to generate focused image. Different sets of multi-focus images have been used in detailed experimentation and compared the results with state-of-the-art existing techniques such as Genetic Algorithm (GA), Principal Component Analysis (PCA), Laplacian Pyramid discrete wavelet transform (DWT), and aDWT for image fusion. It has been found that proposed method performs well as compare to existing methods.

  相似文献   
5.
提出了一种用无单元法模拟弹性体中三维不连续面的处理方法。该法采用可视准则来处理不连续面对高斯点影响域的隔离作用并考虑不连续面两表面的相互作用对整体平衡方程组的贡献。为此,推导了不连续面对整体平衡方程组的贡献方程,研究了模拟不连续面实际接触状态的非线性迭代算法。在上述基础上,编制了模拟三维不连续面的无单元法程序。最后,应用上述方法和程序对一含裂纹的立方体进行了受力分析,结果表明该方法和程序是合理可行的。  相似文献   
6.
徐春凤  韩成  姜会林 《兵工学报》2016,37(11):2015-2021
为研究航空平台间激光通信系统中主要环节和信道对信标光功率的影响,根据捕获探测器的信噪比和探测概率关系,分析激光器发射到探测器接收全环节的信标光功率变化情况,建立了空空激光通信捕获链路仿真系统。通过该仿真系统,分析不同大气能见度所对应的探测概率,在此基础上讨论要实现探测概率为99%,需要的最小发射功率和最长通信距离。仿真结果表明:发射功率越大,大气能见度对航空平台间激光通信探测概率的影响越明显;发射功率不变,大气能见度越高时,最长链路距离越远;当发射功率为5 W,地面能见度大于等于10 km时,即可实现150 km的激光链路。通过仿真系统得出了信标光发射功率与探测概率之间的关系,对激光器的选择起到一定的借鉴作用。在仿真的基础上,开展的飞机间野外试验,可以有效地模拟飞机间激光通信系统的捕获探测概率。  相似文献   
7.
能见度仪校准系统作为能见度校准的标准器,其不确定度直接影响到前向散射式能见度仪的校准结果。介绍了国家级能见度仪校准实验室的能见度仪校准系统的组成和校准方法,分析了校准系统不确定度的主要来源,依据国家计量校准规范JJF 1059.1-2012《测量不确定度评定与表示》,利用能见度测量数据,对校准系统A类和B类不确定度进行了评定分析,并对3台前向散射式能见度仪进行了校准试验。结果显示,整个校准系统在能见度3 000 m以下,扩展不确定度为5.8%,校准后的3台前向散射式能见度仪在100、500、1 000、1 500、2 000、3 000 m六个测试点的相对误差,最大为7.8%,最小为1.8%,满足能见度仪校准和实际观测要求。  相似文献   
8.
Visibility Culling Algorithm with Hierarchical Adaptive Bounding Setting   总被引:1,自引:0,他引:1  
Visibility determination is an i mportant task incomputer graphics.The goal of visibility determina-tion is to efficiently determine visible parts of themodel given a viewpoint and a viewing direction.Toachieve the output-sensitivity of the visibility algo-rithm,we exploit the idea of hierarchical adaptivebounding setting(HABS);it is used to effectivelydetermine a subset of potentially visible sets(PVS)objects.In addition,some flexible culling strategiestoi mprove frame rate per second are …  相似文献   
9.
在基于后向散射原理的大气能见度测量过程中,大气消光系数边界值的选取对反演精度具有较大影响。提出一种基于弦截法的大气消光系数边界值的确定方法,并利用迭代的思想对边界值的选取结果进行修正。通过理论仿真和实地测量对本方法的可行性进行验证,结果表明,弦截法具有较快的收敛速度,且迭代次数较少,经过比对迭代修正之后的消光系数边界值可以更准确的反演出大气消光系数,进而实现大气能见度的高精度测量,具有较强的实际应用价值。  相似文献   
10.
近年来发生的火灾多在人员密集场所,当突发事件发生时,人员疏散往往特别困难,因此,规划行人在大型公众聚集建筑物中的疏散路径非常重要。基于能见度图建构的元胞疏散最短路径模型可直接用于实际的紧急疏散指示路径的规划,避免设置大量逃生指示装置致使工程成本过高及视觉不美观,并且也解决了有限制逃生指示装置数量当作限制条件的最大涵盖面积的求解复杂、空间大的问题。  相似文献   
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