Musial Frauke, Kowalski Axel, Treiber Annemarie, Enck Paul
Biological and Clinical Psychology, Friedrich-Schiller-University, Am Steiger 3/Haus 1, D-07743 Jena, Germany.
Physiol Behav. 2006 Jan 30;87(1):206-18. doi: 10.1016/j.physbeh.2005.08.012. Epub 2005 Oct 25.
Correlations between meal size and inter-meal intervals as a characteristic of ingestive behavior are generally calculated utilizing Pearson's correlation coefficient. However, this commonly used method may exhibit disadvantages and methodological problems when dealing with dependent time series. Alternatively, a modified version of Pearson's r (r(diff)) or a nonparametric procedure, Pfanzagl's T combined with an expanded sampling theorem offer a statistical alternative for correlational analysis, robust to stochastic interdependencies between time series. In two studies, porcine self-initiated feeding behavior was observed in a closed economy setup, and a comparison of all three correlation coefficients was performed. STUDY 1: Twelve Munich mini-pigs were observed for 2 weeks. The rate of food ingestion was a stable characteristic of each individual pig, feeding and defecation behavior were temporally associated and light/dark cycle differences were seen for feeding. STUDY 2: Eight Munich mini-pigs were studied for 4 weeks. Kendall's Tau was utilized to test the stability of feeding behavior across weeks. Stability increased over time and feeding was more stable during the light period. Both correlation measures revealed a strong association between meal size and inter-meal intervals.
Munich-miniature pigs exhibited a stable pattern of self-initiated ingestive and excretory behaviors. In both studies, Pfanzagl's T-values as well as r(diff)-values revealed a corresponding and consistent association between meal size and inter-meal intervals. In combination with the conventional Pearson's r, all three coefficients characterize different aspects of feeding behavior.
进食行为特征中，餐量与餐间间隔的相关性通常使用皮尔逊相关系数来计算。然而，这种常用方法在处理相关时间序列时可能存在缺点和方法问题。另外，皮尔逊r的修正版（r(diff)）或非参数程序，即潘扎格T结合扩展抽样定理，为相关分析提供了一种统计替代方法，对时间序列之间的随机相互依赖性具有稳健性。在两项研究中，在封闭经济环境中观察了猪的自主进食行为，并对所有三个相关系数进行了比较。研究1：观察12只慕尼黑小型猪两周。食物摄取率是每只猪的稳定特征，进食和排便行为在时间上相关，且进食存在昼夜周期差异。研究2：对8只慕尼黑小型猪进行了四周研究。使用肯德尔等级相关系数检验进食行为在数周内的稳定性。稳定性随时间增加，且在光照期进食更稳定。两种相关测量方法均显示餐量与餐间间隔之间存在强关联。
慕尼黑小型猪表现出稳定的自主进食和排泄行为模式。在两项研究中，潘扎格T值以及r(diff)值均显示餐量与餐间间隔之间存在相应且一致的关联。与传统的皮尔逊r相结合，所有三个系数表征了进食行为的不同方面。
