2,761 research outputs found
Fore Tarsus Attachment Device of the Male Scuttle Fly, Aenigmatias lubbockii
The fore tarsus of the male scuttle fly, Aenigmatias lubbockii (Verrall) (Diptera: Phoridae), is broad and equipped with flattened and apically truncated (FAT) setae on the ventral surface, which are suggested to be involved in the intraspecific phoretic behaviour including airlifting and dispersal of the female. The combination of FAT setae on the male fore tarsi and regularly arranged microtrichia on the female thoracic surfaces is suggested to form a combination of an adhesive structure and possibly a fastener system. Comparisons are made to Puliciphora borinquenensis (Wheeler), which also has apterous females and male-facilitated female dispersal, but where fore tarsal FAT setae are absent
Ahead of the curve: three approaches to mass digitisation of vials with a focus on label data capture
There has been little research on novel approaches to digitising liquid-preserved natural history specimens stored in jars or vials. This paper discusses and analyses three different prototypes for high-throughput digitisation using cheap, readily available components. This paper has been written for other digitisation teams or curators who want to trial or improve upon these new digitisation approaches in liquid preserved collections.This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
The attached file is the published pdf.NHM Repositor
Species‐level image classification with convolutional neural network enables insect identification from habitus images
1. Changes in insect biomass, abundance, and diversity are challenging to track at
sufficient spatial, temporal, and taxonomic resolution. Camera traps can capture
habitus images of ground-dwelling insects. However, currently sampling involves
manually detecting and identifying specimens. Here, we test whether a convolutional neural network (CNN) can classify habitus images of ground beetles to
species level, and estimate how correct classification relates to body size, number
of species inside genera, and species identity.
2. We created an image database of 65,841 museum specimens comprising 361
carabid beetle species from the British Isles and fine-tuned the parameters of a
pretrained CNN from a training dataset. By summing up class confidence values
within genus, tribe, and subfamily and setting a confidence threshold, we trade-off
between classification accuracy, precision, and recall and taxonomic resolution.
3. The CNN classified 51.9% of 19,164 test images correctly to species level and
74.9% to genus level. Average classification recall on species level was 50.7%.
Applying a threshold of 0.5 increased the average classification recall to 74.6% at
the expense of taxonomic resolution. Higher top value from the output layer and
larger sized species were more often classified correctly, as were images of species in genera with few species.
4. Fine-tuning enabled us to classify images with a high mean recall for the whole
test dataset to species or higher taxonomic levels, however, with high variability.
This indicates that some species are more difficult to identify because of properties such as their body size or the number of related species.
5. Together, species-level image classification of arthropods from museum collections
and ecological monitoring can substantially increase the amount of occurrence
data that can feasibly be collected. These tools thus provide new opportunities in
understanding and predicting ecological responses to environmental change.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium,
provided the original work is properly cited.
© 2019 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
The attached file is the published pdf
Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV
The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8 TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
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