Implicit media frames: Automated analysis of public debate on artificial sweeteners

The framing of issues in the mass media plays a crucial role in the public understanding of science and technology. This article contributes to research concerned with diachronic analysis of media frames by making an analytical distinction between implicit and explicit media frames, and by introducing an automated method for analysing diachronic changes of implicit frames. In particular, we apply a semantic maps method to a case study on the newspaper debate about artificial sweeteners, published in The New York Times (NYT) between 1980 and 2006. Our results show that the analysis of semantic changes enables us to filter out the dynamics of implicit frames, and to detect emerging metaphors in public debates. Theoretically, we discuss the relation between implicit frames in public debates and codification of information in scientific discourses, and suggest further avenues for research interested in the automated analysis of frame changes and trends in public debates

Isotopic signatures of methane emissions from tropical fires, agriculture and wetlands: the MOYA and ZWAMPS flights

We report methane isotopologue data from aircraft and ground measurements in Africa and South America. Aircraft campaigns sampled strong methane fluxes over tropical papyrus wetlands in the Nile, Congo and Zambezi basins, herbaceous wetlands in Bolivian southern Amazonia, and over fires in African woodland, cropland and savannah grassland. Measured methane δ13CCH4 isotopic signatures were in the range −55 to −49‰ for emissions from equatorial Nile wetlands and agricultural areas, but widely −60 ± 1‰ from Upper Congo and Zambezi wetlands. Very similar δ13CCH4 signatures were measured over the Amazonian wetlands of NE Bolivia (around −59‰) and the overall δ13CCH4 signature from outer tropical wetlands in the southern Upper Congo and Upper Amazon drainage plotted together was −59 ± 2‰. These results were more negative than expected. For African cattle, δ13CCH4 values were around −60 to −50‰. Isotopic ratios in methane emitted by tropical fires depended on the C3 : C4 ratio of the biomass fuel. In smoke from tropical C3 dry forest fires in Senegal, δ13CCH4 values were around −28‰. By contrast, African C4 tropical grass fire δ13CCH4 values were −16 to −12‰. Methane from urban landfills in Zambia and Zimbabwe, which have frequent waste fires, had δ13CCH4 around −37 to −36‰. These new isotopic values help improve isotopic constraints on global methane budget models because atmospheric δ13CCH4 values predicted by global atmospheric models are highly sensitive to the δ13CCH4 isotopic signatures applied to tropical wetland emissions. Field and aircraft campaigns also observed widespread regional smoke pollution over Africa, in both the wet and dry seasons, and large urban pollution plumes. The work highlights the need to understand tropical greenhouse gas emissions in order to meet the goals of the UNFCCC Paris Agreement, and to help reduce air pollution over wide regions of Africa

Reassessing the variability in atmospheric H2 using the two-way nested TM5 model

This work reassesses the global atmospheric budget of H₂ with the TM5 model. The recent adjustment of the calibration scale for H₂ translates into a change in the tropospheric burden. Furthermore, the ECMWF Reanalysis-Interim (ERA-Interim) data from the European Centre for Medium-Range Weather Forecasts (ECMWF) used in this study show slower vertical transport than the operational data used before. Consequently, more H2 is removed by deposition. The deposition parametrization is updated because significant deposition fluxes for snow, water, and vegetation surfaces were calculated in our previous study. Timescales of 1–2 h are asserted for the transport of H2 through the canopies of densely vegetated regions. The global scale variability of H₂ and δD[H2] is well represented by the updated model. H₂ is slightly overestimated in the Southern Hemisphere because too little H2 is removed by dry deposition to rainforests and savannahs. The variability in H2 over Europe is further investigated using a high-resolution model subdomain. It is shown that discrepancies between the model and the observations are mainly caused by the finite model resolution. The tropospheric burden is estimated at 165+- 8 Tg H2. The removal rates of H2 by deposition and photochemical oxidation are estimated at 53 +- 4 and 23 +- 2 Tg H2/yr, resulting in a tropospheric lifetime of 2.2 +- 0.2 year

Reassessing the variability in atmospheric H2 using the two-way nested TM5 model

This work reassesses the global atmospheric budget of H₂ with the TM5 model. The recent adjustment of the calibration scale for H₂ translates into a change in the tropospheric burden. Furthermore, the ECMWF Reanalysis-Interim (ERA-Interim) data from the European Centre for Medium-Range Weather Forecasts (ECMWF) used in this study show slower vertical transport than the operational data used before. Consequently, more H2 is removed by deposition. The deposition parametrization is updated because significant deposition fluxes for snow, water, and vegetation surfaces were calculated in our previous study. Timescales of 1–2 h are asserted for the transport of H2 through the canopies of densely vegetated regions. The global scale variability of H₂ and δD[H2] is well represented by the updated model. H₂ is slightly overestimated in the Southern Hemisphere because too little H2 is removed by dry deposition to rainforests and savannahs. The variability in H2 over Europe is further investigated using a high-resolution model subdomain. It is shown that discrepancies between the model and the observations are mainly caused by the finite model resolution. The tropospheric burden is estimated at 165+- 8 Tg H2. The removal rates of H2 by deposition and photochemical oxidation are estimated at 53 +- 4 and 23 +- 2 Tg H2/yr, resulting in a tropospheric lifetime of 2.2 +- 0.2 year

"The post-antibiotic apocalypse" and the "war on superbugs": catastrophe discourse in microbiology, its rhetorical form and political function

Discourses evoking an antibiotic apocalypse and a war on superbugs are emerging just at a time when so-called "catastrophe discourses" are undergoing critical and reflexive scrutiny in the context of global warming and climate change. This article combines insights from social science research into climate change discourses with applied metaphor research based on recent advances in cognitive linguistics, especially with relation to "discourse metaphors." It traces the emergence of a new apocalyptic discourse in microbiology and health care, examines its rhetorical and political function and discusses its advantages and disadvantages. It contains a reply by the author of the central discourse metaphor, "the post-antibiotic apocalypse," examined in the article

IgA and IgG antibody responses following systemic immunization of cattle with native H7 flagellin differ in epitope recognition and capacity to neutralise TLR5 signalling

Systemic immunization of cattle with H7 flagellin results in induction of both H7-specific IgA and IgG antibodies but only partially protects against subsequent colonization with Escherichia coli O157:H7. Recent studies indicate that anti-flagellin antibodies directed against TLR5 binding domains located in the conserved N- and C-terminal domains of flagellin can neutralise TLR5 activation and impair vaccine efficacy. In the current study we determined whether systemic immunization of cattle with H7 flagellin induces antibodies capable of interfering with flagellin-mediated TLR5 activation. Both anti-H7 IgG1 and IgG2 but not IgA antibodies recognised epitopes within the conserved N- and C-terminal domains of H7 flagellin, and purified H7-specific IgG but not IgA was capable of inhibiting H7-mediated TLR5 activation in vitro. These results suggest that (i) IgA and IgG isotypes originated from different populations of B cells and (ii) systemically induced H7-specific IgG but not IgA may impair innate immune responses to E. coli 0157: H7 via neutralisation of TLR5 activation and subsequently reduce vaccine efficacy