A new family of standardized and symmetric indices for measuring the intensity and importance of plant neighbour effects

1. Measurements of competition and facilitation between plants often rely upon intensity and importance indices that quantify the net effect of neighbours on the performance of a target plant. A systematic analysis of the mathematical behaviour of the indices is lacking and leads to structural pitfalls, e.g. statistical problems detected in importance indices. 2. We summarize and analyse themathematical properties that the indices should display. We reviewthe properties of the commonly used indices focusing on standardization and symmetry, which are necessary to avoid compromising data interpretation.We introduce a new family of indices ‘Neighbour-effect Indices’ that meet all the proposed properties. 3. Considering the commonly used indices, none of the importance indices are standardized, and onlyRII (Relative Interaction Index) displays all the required mathematical properties. The existing indices show two types of symmetries, namely, additive or commutative, which are currently confounded, potentially resulting in misleading interpretations. Our Neighbour-effect Indices encompass two intensity and two importance indices that are standardized and have different and defined symmetries. 4. Our new additive intensity index, NIntA, is the first of its kind, and it is generally more suitable for assessing competition and facilitation intensity than the widely used RII, which may underestimate facilitation. Our new standardized importance indices solve the main statistical problems that are known to affectCimp and Iimp. Intensity and importance with the same symmetry should be used within the same study. The Neighbour-effect Indices, sharing the same formulation, will allow for unbiased comparisons between intensity and importance, and between types of symmetry.The research of R.D.S. was supported by funding from Ministry of Economy and Competitivity (AGL2015-69151-R). V.R.D. was supported by a Ram on y Cajal fellowship (RYC-2012-10970, MINECO, Spain). The research of M.B. and M.R. was supported by funding from the European Union’s Seventh Framework Programme (FP7/2007–2013), grant agreement 283068 (CASCADE). M.V. was supported by an NWO–ALW ‘open competition’ grant. (Netherlands Science Foundation – Earth and Life Sciences, project number 820.01.020.)

Palmitoyl carnitine : an endogenous promoter of calcium efflux from rat heart mitochondria

Original article can be found at: http://www.sciencedirect.com/science/journal/00062952 Copyright Elsevier Inc. DOI: 10.1016/0006-2952(88)90307-3 [Full text of this article is not available in the UHRA]The effects of the fatty acid ester palmitoyl carnitine (PC) on mitochondrial Ca2+ handling and ATP synthesis are described. At low concentrations (5–40 μM) PC was found to produce changes in mitochondrial Ca2+ handling, the most significant effect (P < 0.05) being the promotion of Ca2+ efflux (EC25 = 1.19 ± 0.11 μM). Studies on mitochondrial substrate oxidation in the presence of either glutamate plus malate, or succinate, confirmed the ability of PC (10–100 μM) to cause loss of respiratory control as shown by reductions in the Respiratory Control Index for each substrate. It was concluded that the effect of PC on Ca2+ transport was due to a direct action on the Na+---Ca2+ antiporter system, whilst the effect on respiration was due to an uncoupling action.Peer reviewe

Bay K 8644, modifier of calcium transport and energy metabolism in rat heart mitochondria: a new intracellular site of action

Copyright British Pharmacological Society [Full text of this article is not available in the UHRA]Peer reviewe