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Menzel's `Coefficient of Scalability' (CofS) (See SA 687) & Jackson's `Plus Percentage Ratio' (PPR) are intended to be more accurate measures of acalability than Guttman's CofR. In evaluating some affective checklist data 3 measures were used. The results using CofS for individual items proved to be identical with those obtained by computing PPR's. Moreover, if one uses formula (1) to compute the PPR for the entire scale the figure obtained is identical with that for CofS. (formula not translated) In accepting or rejecting a set of data as scalable the author considers both CofS & CofR. Individual items are chosen on the basis of reproducibility & response category f's. PPR occasionally may be of help in judging the quality of an item. However, it is not a precise measure for items with extreme Maxginals. W. Delany.

A. conceptual framework, through which accident variables are defined and certain cause-and-effect relationships are established, is confirmed through application of the technique of factor analysis to a set of lightplane accident data. Relationships between aircraft structural damage and injury to the occupant were seen to increase as a function of proximity. Individual measures of the consequences of impact were found to inter correlate higher than the implied cause-effect relations from impact to damage.

Running waters contribute substantially to global carbon fluxes through decomposition of terrestrial plant litter by aquatic microorganisms and detritivores. Diversity of this litter may influence instream decomposition globally in ways that are not yet understood. We investigated latitudinal differences in decomposition of litter mixtures of low and high functional diversity in 40 streams on 6 continents and spanning 113° of latitude. Despite important variability in our dataset, we found latitudinal differences in the effect of litter functional diversity on decomposition, which we explained as evolutionary adaptations of litter-consuming detritivores to resource availability. Specifically, a balanced diet effect appears to operate at lower latitudes versus a resource concentration effect at higher latitudes. The latitudinal pattern indicates that loss of plant functional diversity will have different consequences on carbon fluxes across the globe, with greater repercussions likely at low latitudes. ; This study was part of the DecoDiv project conducted by the GLoBE network (www.globenetwork.es), which is coordinated by L.B. Most research was based on crowdfunding (details on specific funding sources at each region are given in the Supplementary Materials). Project coordination was funded by Basque Government funds (ref. IT951-16) to the Stream Ecology Group (UPV/EHU, Spain). Litter trait analyses were funded by the 2014–2020 Operational Programme FEDER Andalusia, Spain (ref. UAL18-RNM-B006-B to J.J.C.) and the Portuguese Science Foundation, Portugal (ref. UIDB/04292/2020 to MARE). ; Peer reviewed

he relationship between detritivore diversity and decomposition can provide information on how biogeochemical cycles are affected by ongoing rates of extinction, but such evidence has come mostly from local studies and microcosm experiments. We conducted a globally distributed experiment (38 streams across 23 countries in 6 continents) using standardised methods to test the hypothesis that detritivore diversity enhances litter decomposition in streams, to establish the role of other characteristics of detritivore assemblages (abundance, biomass and body size), and to determine how patterns vary across realms, biomes and climates. We observed a positive relationship between diversity and decomposition, strongest in tropical areas, and a key role of abundance and biomass at higher latitudes. Our results suggest that litter decomposition might be altered by detritivore extinctions, particularly in tropical areas, where detritivore diversity is already relatively low and some environmental stressors particularly prevalent. ; This study was part of the DecoDiv project conducted by the GLoBE network (www.globenetwork.es), which is coordinated by L. B. Most research was based on crowdfunding (details on specific funding sources at each region are given in Supplementary Information). Project coordination was funded by Basque Government funds (Ref. IT951-16) to the Stream Ecology Group (UPV/EHU, Spain). ; Peer reviewed