Photovoltaics at multi-terawatt scale: Waiting is not an option.

25% annual PV growth is possible over the next decade.

CrowdCurio: an online crowdsourcing platform to facilitate climate change studies using herbarium specimens.

Phenology is a key aspect of plant success. Recent research has demonstrated that herbarium specimens can provide important information on plant phenology. Massive digitization efforts have the potential to greatly expand herbarium-based phenological research, but also pose a serious challenge regarding efficient data collection. Here, we introduce CrowdCurio, a crowdsourcing tool for the collection of phenological data from herbarium specimens. We test its utility by having workers collect phenological data (number of flower buds, open flowers and fruits) from specimens of two common New England (USA) species: Chelidonium majus and Vaccinium angustifolium. We assess the reliability of using nonexpert workers (i.e. Amazon Mechanical Turk) against expert workers. We also use these data to estimate the phenological sensitivity to temperature for both species across multiple phenophases. We found no difference in the data quality of nonexperts and experts. Nonexperts, however, were a more efficient way of collecting more data at lower cost. We also found that phenological sensitivity varied across both species and phenophases. Our study demonstrates the utility of CrowdCurio as a crowdsourcing tool for the collection of phenological data from herbarium specimens. Furthermore, our results highlight the insight gained from collecting large amounts of phenological data to estimate multiple phenophases.

Prion protein NMR structures of cats, dogs, pigs, and sheep.

The NMR structures of the recombinant cellular form of the prion proteins (PrPC) of the cat (Felis catus), dog (Canis familiaris), and pig (Sus scrofa), and of two polymorphic forms of the prion protein from sheep (Ovis aries) are presented. In all of these species, PrPC consists of an N-terminal flexibly extended tail with approximately 100 amino acid residues and a C-terminal globular domain of approximately 100 residues with three alpha-helices and a short antiparallel beta-sheet. Although this global architecture coincides with the previously reported murine, Syrian hamster, bovine, and human PrPC structures, there are local differences between the globular domains of the different species. Because the five newly determined PrPC structures originate from species with widely different transmissible spongiform encephalopathy records, the present data indicate previously uncharacterized possible correlations between local features in PrPC three-dimensional structures and susceptibility of different mammalian species to transmissible spongiform encephalopathies.

NMR structure of the bovine prion protein isolated from healthy calf brains.

NMR structures of recombinant prion proteins from various species expressed in Escherichia coli have been solved during the past years, but the fundamental question of the relevancy of these data relative to the naturally occurring forms of the prion protein has not been directly addressed. Here, we present a comparison of the cellular form of the bovine prion protein isolated and purified from healthy calf brains without use of detergents, so that it contains the two carbohydrate moieties and the part of the GPI anchor that is maintained after enzymatic cleavage of the glycerolipid moiety, with the recombinant bovine prion protein expressed in E. coli. We show by circular dichroism and (1)H-NMR spectroscopy that the three-dimensional structure and the thermal stability of the natural glycoprotein and the recombinant polypeptide are essentially identical. This result indicates possible functional roles of the glycosylation of prion proteins in healthy organisms, and provides a platform and validation for future work on the structural biology of prion proteins, which will have to rely primarily on the use of recombinant polypeptides.