Revisiting a central prediction of the Gill Oxygen Limitation Theory: Gill area index and growth performance

The Gill Oxygen Limitation Theory (GOLT) posits that a mismatch in oxygen supply and demand stemming from geometric constraints on gill surface area limits metabolic rate and energy available for biological processes. This theory has been suggested to explain numerous phenomena observed with warming yet is based upon a relationship among maximum size, growth, and gill surface area established over 40 years ago. However, the metric used in this relationship to characterize gill surface area, gill area index, fails to capture the known variability in the scaling of gill surface area and is biased by the sizes at which gills were measured. Here, we revisit a central prediction of the GOLT, asking four key questions that examine limitations in the original relationship. We find that gill area index does indeed explain variation in growth performance across 132 species of fish and this relationship is strikingly similar to the original relationship across 42 species. Yet, we argue that gill area index is not an adequate measure of gill surface area because (1) gill surface area has a non-linear relationship with size and, thus, changes ontogenetically as an individual grows over time and (2) because it is based on mean estimates of both gill surface area and body mass. Indeed, we show that the value of gill area index for a given species is variable depending on how it is calculated. We therefore suggest a pathway forward for assessing whether gill surface area is an important factor in explaining variation in growth performance.     

具有椭圆盘极点约束的线性系统滤波器设计

整理者认为《为狱等状四种》中“吏议”的主体为县吏，然县吏似无权参与案件的审判，而直接听命于郡守的都吏是有断狱和向廷尉奏谳的权力的，故“吏议”之主体当为都吏。一般认为“邦亡”指逃出国境，然从《癸、琐相移谋购案》可知秦人逃亡到南郡被定为“邦亡”罪，而案发时南郡早已划入秦版图之中，故知“邦亡”当为逃离秦故地，而非逃离国境。“邦亡”是一定历史时期内秦国特有的称谓，秦统一后该词未见于文献之中。