The effect of pair housing on dairy calf health,performance, and behavior

Individual housing of dairy calves prevails in Europe and North America despite its negative effects on calf development. One of the main reasons is that farmers find individual housing of calves more practical than group housing. A compromise between practice and welfare could be housing calves in pairs. Therefore, we aimed to compare health, feed intake, growth, and behavior in a novel arena of 22 individually (INDI) and 44 pair-housed calves that were randomly assigned a treatment. Diarrhea and respiratory problems were recorded every day for the period of 49 d. Intake of calf starter and milk were measured every day for the period 48 and 49 d, respectively. Calf body weight gains were calculated as average daily gain. Calves were individually tested in a novel arena at 11 to 18 d, and their behavior was recorded according to an ethogram including 8 behavioral categories. Behavioral categories were first diminished by principal component (PC) analysis. We found that 2 PC explained 66% of the total variation in calf behavior. Movement-related behaviors (activity, play, and crossing the stair) loaded positively on PC1, and PC2 had positive loading on self-grooming and negative loading on exploration. There were no effects of housing on calf health, feed intake, or average daily gain. The INDI calves had higher PC1 scores than pair-housed calves, indicating a rebound effect of movement. Our results are consistent with other studies that found no negative effect of pair housing of calves on their health, feed intake, or growth compared with individually-housed calves. The rebound effect of movement-related behaviors of INDI calves in a novel arena implies that individual housing of calves causes activity deprivation by the second week of age.     

水文综合改变度动态评估模型构建与应用

根据龙羊峡水库下游贵德水文站1954～2017年流量数据,利用粗糙集理论、集对分析理论及变化范围法确定水文综合改变度,通过集对-马氏链评估方法建立了一种关于水文综合改变度的动态评估模型,探讨龙羊峡水库水文综合改变度变化及趋势。结果表明,该模型在时段预测及稳态预测有较好的表现;2013～2017年时段的模型预测结果与实际计算结果相同,同为中度改变;现阶段水文综合改变度处于高度改变状态,但具有逐渐向好的态势,经多个周期变化达到稳定态势后呈现为低度改变。     

关闭矿山社会生态系统恢复力评价研究 ——以徐州市大黄山矿区为例

本文以徐州市大黄山矿区为研究对象,从社会、生态、经济三大系统遴选18个指标,构建矿区社会生态系统恢复力评价指标体系,运用集对分析法评价系统恢复力,揭示大黄山矿区闭矿以来恢复力变化趋势。结果表明:2000～2014年间大黄山镇社会生态系统受到的扰动指数居于0.43～0.54之间,应对能力指数从0.23上升到0.77;2000～2014年间大黄山镇社会生态系统总恢复力指数从0.32上升到0.72;经济发展水平对矿区社会生态恢复力的影响较大,是矿区转型发展的主要支撑。     

量子保密术和保密通信

基于量子物理原理的量子密码术已被证明是保密通信中密钥安全分配的有效手段．本文介绍了量子密码的基本原理，探讨了实现量子密码的几种方案，并研究了各自的密钥分配机制．还讨论了量子密码通信的历史发展和指出现存在的问题以及未来的发展前景。     

网络可用带宽的高精度测量算法

精确的网络带宽测量对于许多Internet应用和协议都有很重要的作用.本文在分析网络可用带宽测量算法IGI的基础上,提出了改进算法.改进算法在准确性和跟踪可用带宽变化的能力等方面和原来算法相比有很大的改善.另外,针对PTR算法测量结果不稳定以及在网络路径的瓶颈链路的利用率较高时测量不准确的问题,提出改进算法.实验表明,改进的PTR算法在测量时间以及测量负载增加量不大的情况下,提高了测量的准确性,使得测量结果更平稳,并且能很好地跟随网络路径可用带宽的变化.     

A New Improved Method for Symbolic Reliability Analysis

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Formation Mechanism of Epitaxial Palladium–Platinum Core–Shell Nanocatalysts in a One‐Step Supercritical Synthesis

The scarcity of platinum group metals provides a strong incentive to optimize the catalytic activity and stability, e.g., through nanoalloys or core–shell nanoparticles. Here, time‐resolved X‐ray total scattering and transmission electron microscopy characterization are used to study the formation of palladium–platinum core–shell nanoparticles under solvothermal conditions. It is shown that Pd rapidly forms small (5–10 nm), disordered primary particles, which agglomerate and crystallize when reaching 20–25 nm. The primary Pd particles provide nucleation sites for Pt, and, with extended reaction time, the Pd cores become fully covered with Pt shells. The observed core–shell material is surprising when considering the Pt–Pd phase diagram and relative surface energies, but it can be rationalized through the kinetics of precursor conversion. To bridge the gap between scientific studies and industrial demand for large‐scale production, the synthesis process is successfully transferred to a continuous flow supercritical reactor providing a simple scalable and green process for production of bimetallic nanocatalysts.     

基于模糊群决策的天津特色食品包装SPA–TOPSIS评价

目的 针对地方特色食品包装设计需兼具功能性和文化性的特征,开展包装设计方案评价,有效辅助设计开发过程,丰富地方特色食品包装设计的思路。方法 以天津特色食品——麻花包装为研究对象,构建分层次的包装评价准则框架;采用基于梯形模糊数的专家评价法来获得备选方案在各准则上的评分,通过群决策来集结多位专家的评判意见,进而求解得到备选方案的准则值;引入集对分析理论(SPA),采用连接向量距离来替换经典TOPSIS中的欧氏距离,提出SPA–TOPSIS评价方法来实现备选方案的评价和排序。结果 针对麻花的6种包装设计方案,实施了基于模糊群决策的SPA–TOPSIS评价,6种包装设计方案与正理想解的贴近度依次为0.55、0.46、0.53、0.49、0.56、0.44,方案5为最优方案。结论 通过天津特色食品包装评价,完善了城市文化内涵包装设计的理念,为包装的文化性设计提供了重要支持。     

区域水资源可持续利用系统评价的集对分析模型

总结评价区域水资源可持续利用水平的若干指标,应用集对分析理论建立了区域水资源可持续利用系统评价的集对分析模型。用差异度系数分析所论集对的同异反联系,从目标层、准则层、评价指标层等3个层次上系统阐明了集对分析理论在各层指标评价过程中的意义,通过计算区域水资源可持续利用系统评价的n元联系数,确定了某区域水资源可持续利用系统的综合评价级别,评价结论为一般。     

内点法在偶对潮流优化中的应用

当前东北区域电力市场改革试点正处在日前交易开放前阶段，其日调度计划的优化不仅要处理常规约束等一般性问题，而且具有其特殊性，既要保证完成各竞价电厂中长期合同交易分解到日的电能量，又要满足各竞价电厂日负荷率彼此相等，以体现调度上的公平。针对该问题，建立了日前交易开放前的日调度计划优化模型，利用原 — 对偶内点法在处理大量常规不等式约束方面的优势，提出将时段偶对解耦方法与原 — 对偶内点法有机结合，前者处理特殊性问题，后者处理一般性问题，优势互补，使优化算法能较贴切地适应该类日调度计划优化模型的特点和需要。数值算例表明，该方法简洁、有效。