158 research outputs found

    Dietary exposure to PCBs and dioxins.

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    comments on S. Patandin et al. : Dietary exposure to polychlorinated biphenyls and dioxins from infancy until adulthood: a comparison between breast-feeding, toddler, and long-term exposure. Environ Health Perspect 107:45-51 (1999)

    The status quo of research on entrepreneurial orientation : conversational landmarks and theoretical scaffolding

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    This research aims to gain a deeper appreciation of where the entrepreneurial orientation (EO) conversation has gained momentum based upon an analysis of its key conversational landmarks and the studies which have thus far provided its principal theoretical scaffolding. Drawing upon a bibliometric analysis of 62,499 citations from all 822 publications on EO existing so far, thereby building the most comprehensive overview of EO studies collected to date, we are able to identify which studies, journals, and disciplines have offered critical landmarks within the conversation. Moreover, we categorize these influential landmark studies into four primary areas, namely “Defining pieces”, “Methods and measurement”, “Contingencies”, and “Impact”, and discuss how prominent landmarks within the EO conversation have created the current theoretical scaffolding upon which EO research is now building. Notably, our study observes Schumpeter (1934) theory of entrepreneurship and innovation as ‘creative destruction’ as well as Barney (1991) resource-based view (RBV) as landmarks within EO’s present theoretical scaffolding

    Globally invariant metabolism but density-diversity mismatch in springtails.

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    Soil life supports the functioning and biodiversity of terrestrial ecosystems. Springtails (Collembola) are among the most abundant soil arthropods regulating soil fertility and flow of energy through above- and belowground food webs. However, the global distribution of springtail diversity and density, and how these relate to energy fluxes remains unknown. Here, using a global dataset representing 2470 sites, we estimate the total soil springtail biomass at 27.5 megatons carbon, which is threefold higher than wild terrestrial vertebrates, and record peak densities up to 2 million individuals per square meter in the tundra. Despite a 20-fold biomass difference between the tundra and the tropics, springtail energy use (community metabolism) remains similar across the latitudinal gradient, owing to the changes in temperature with latitude. Neither springtail density nor community metabolism is predicted by local species richness, which is high in the tropics, but comparably high in some temperate forests and even tundra. Changes in springtail activity may emerge from latitudinal gradients in temperature, predation and resource limitation in soil communities. Contrasting relationships of biomass, diversity and activity of springtail communities with temperature suggest that climate warming will alter fundamental soil biodiversity metrics in different directions, potentially restructuring terrestrial food webs and affecting soil functioning

    Global fine-resolution data on springtail abundance and community structure

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    Springtails (Collembola) inhabit soils from the Arctic to the Antarctic and comprise an estimated ~32% of all terrestrial arthropods on Earth. Here, we present a global, spatially-explicit database on springtail communities that includes 249,912 occurrences from 44,999 samples and 2,990 sites. These data are mainly raw sample-level records at the species level collected predominantly from private archives of the authors that were quality-controlled and taxonomically-standardised. Despite covering all continents, most of the sample-level data come from the European continent (82.5% of all samples) and represent four habitats: woodlands (57.4%), grasslands (14.0%), agrosystems (13.7%) and scrublands (9.0%). We included sampling by soil layers, and across seasons and years, representing temporal and spatial within-site variation in springtail communities. We also provided data use and sharing guidelines and R code to facilitate the use of the database by other researchers. This data paper describes a static version of the database at the publication date, but the database will be further expanded to include underrepresented regions and linked with trait data.</p
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