LogletLab 5, now in beta version, offers new web-based features for single and multiple logistics. We welcome feedback. We plan in the spring to release 5.1 with more fitting algorithms and also logistic substitution.
Jesse H. Ausubel joins Jason Spiess on The Crude Life to discuss “Peak Human” and “Peak Humans” in a 34-minute podcast and explore new research showing how humans’ minds and bodies may near their limits and even start on a downward curve. “For 200-250 years humanity has had an incredible run,” Ausubel said. “When you think of your great grandparents, grandparents, parents and you, generally speaking you are going to be better… than they were.”
The paper finds that integrating allometry significantly improved correlations between organism abundance and metabarcoding read count relative to traditional metrics of abundance (density and biomass) for bony fishes. Future studies investigating the relationship between eDNA signal strength and metrics of fish abundance could improve by accounting for allometry; to this end, the paper develops an online tool that can facilitate the integration of allometry in eDNA/abundance relationships.
Explore how accounting for allometric scaling in environmental DNA (eDNA) shedding rates influences the correlation with organism count and abundance data. Users can upload their own datasets and use the slider to vary the allometric scaling coefficient (b). Allometry can be applied intra-specifically (among populations) or interspecifically (among species). Size-distribution data supplied to the function can also either be individual-level (e.g. a size distribution of individuals for each population) or population-level (e.g. the mean mass of individuals within a population).
Journalist/author Robert Bryce interviews Jesse Ausubel about PHE’s work on “peak human” and “peak humans.” The interview covers four dimensions of human performance: the physical (how far and fast can we go?), lifetime (how long can we live and how well?), cognitive (measures of intelligence and learning), and immunity (is our resistance to disease waning?). The podcast was recorded on December 7, 2022. For the audio and transcript, see the Bryce website, and also on YouTube.
We thank Song Sun and Ke Chen for editorial assistance.
Summary: Human and domesticated animal sequences, commonly detected in environmental DNA (eDNA) metabarcoding studies, are routinely excluded from analysis. Here we suggest that reporting human and domesticated animal eDNA results might open new lines of investigation. For example, the relative abundance of human and domesticated animal eDNA as compared to that of wild vertebrate species might provide an index of human impact on local biota. Such an index could be applied to sites ranging from urban harbors to remote villages, and possibly to analyze historical samples. Various potential sources of contamination complicate the picture, but it should be possible to develop procedures that minimize risk of DNA introduction during collection and processing. Our near-term recommendation is to encourage inclusion of human and domesticated animal data in eDNA publications as an incentive for discovery, to lift quality controls, and to collectively contribute to new vistas that eDNA science might open.
While our paper focuses on fish, we believe the approach of “spiking” samples collected in nature with known amounts of DNA from a species that would not be present in the sample (such as ostrich) offers great promise for increasing the value of a wide range of aquatic DNA studies. The exhibit below shares some of the main points from the paper.