984 research outputs found

    A Comparative Framing Analysis of Embedded and Behind-the-Lines Reporting on the 2003 Iraq War

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    Although a contested position, we believe that reporters and editors frame the news in a way that reflects their personal feelings and newsroom culture (Kuypers, 1997, 2002, 2005; Cooper, in press). Audiences usually receive their political news from only a few press sources; rarely do they read the original statements of those being reported upon

    The President and the Press: The Framing of George W. Bush’s Speech to the United Nations

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    In this essay, we provide a brief overview of how frames work, discuss the relationship of frames to the news media, and perform a qualitatively based, comparative framing analysis of President Bush’s speech to the United Nations and the mainstream American press response that followed. Findings suggest that by the end of formal military operations in Afghanistan, the press was increasingly framing its reports in such a way that President Bush’s public statements were inaccurately transmitted to the public at large. Three key findings are advanced: one, the press depicted the Bush administration as an enemy of civil liberties; two, hard news stories echoed the positions generated by editorials and opinion essays; three, as early as eight weeks after 9/11, the press was actively contesting the meaning of the War on Terror. Also discussed is the nature of the War on Terror as a master frame

    George W. Bush, the American Press, and the Initial Framing of the War on Terror after 9/11

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    President George W. Bush\u27s speech to the General Assembly of the United Nations on November I 0, 200 I, marks an important moment in the history of the War on Terror. 1 It followed closely upon the joint U.S.-Northern Alliance military capture of Mazari Sarif, Afghanistan, which significantly disrupted the Taliban\u27s operations and arguably marked the official beginning of America\u27s War on Terror. As President Bush stated, The time for sympathy has now passed; the time for action has now arrived. 2 In some ways, the speech offered nothing new. It reiterated words and ideas that the president frequently used to label elements of the situation following the 9/11 attacks

    Nitric oxide turnover in permeable river sediment

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    We measured nitric oxide (NO) microprofiles in relation to oxygen (O-2) and all major dissolved N-species (ammonium, nitrate, nitrite, and nitrous oxide [N2O]) in a permeable, freshwater sediment (River Weser, Germany). NO reaches peak concentrations of 0.13 mu mol L-1 in the oxic zone and is consumed in the oxic-anoxic transition zone. Apparently, NO is produced by ammonia oxidizers under oxic conditions and consumed by denitrification under microoxic conditions. Experimental percolation of sediment cores with aerated surface water resulted in an initial rate of NO production that was 12 times higher than the net NO production rate in steady state. This initial NO production rate is in the same range as the net ammonia oxidation rate, indicating that NO is transiently the main product of ammonia oxidizers. Stable isotope labeling experiments with the N-15-labeled chemical NO donor S-nitroso-N-acetylpenicillamine (SNAP) (1) confirmed denitrification as the main NO consumption pathway, with N2O as its major product, (2) showed that denitrification combines one free NO molecule with one NO molecule formed from nitrite to produce N2O, and (3) suggested that NO inhibits N2O reduction

    Mechanisms of transient nitric oxide and nitrous oxide production in a complex biofilm

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    Nitric oxide (NO) and nitrous oxide (N2O) are formed during N-cycling in complex microbial communities in response to fluctuating molecular oxygen (O2) and nitrite (NO2−) concentrations. Until now, the formation of NO and N2O in microbial communities has been measured with low spatial and temporal resolution, which hampered elucidation of the turnover pathways and their regulation. In this study, we combined microsensor measurements with metabolic modeling to investigate the functional response of a complex biofilm with nitrifying and denitrifying activity to variations in O2 and NO2−. In steady state, NO and N2O formation was detected if ammonium (NH4+) was present under oxic conditions and if NO2− was present under anoxic conditions. Thus, NO and N2O are produced by ammonia-oxidizing bacteria (AOB) under oxic conditions and by heterotrophic denitrifiers under anoxic conditions. NO and N2O formation by AOB occurred at fully oxic conditions if NO2− concentrations were high. Modeling showed that steady-state NO concentrations are controlled by the affinity of NO-consuming processes to NO. Transient accumulation of NO and N2O occurred upon O2 removal from, or NO2− addition to, the medium only if NH4+ was present under oxic conditions or if NO2− was already present under anoxic conditions. This showed that AOB and heterotrophic denitrifiers need to be metabolically active to respond with instantaneous NO and N2O production upon perturbations. Transiently accumulated NO and N2O decreased rapidly after their formation, indicating a direct effect of NO on the metabolism. By fitting model results to measurements, the kinetic relationships in the model were extended with dynamic parameters to predict transient NO release from perturbed ecosystems

    The rate and fate of N-2 and C fixation by marine diatom-diazotroph symbioses

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    N-2 fixation constitutes an important new nitrogen source in the open sea. One group of filamentous N-2 fixing cyanobacteria (Richelia intracellularis, hereafter Richelia) form symbiosis with a few genera of diatoms. High rates of N-2 fixation and carbon (C) fixation have been measured in the presence of diatom-Richelia symbioses. However, it is unknown how partners coordinate C fixation and how the symbiont sustains high rates of N-2 fixation. Here, both the N-2 and C fixation in wild diatom-Richelia populations are reported. Inhibitor experiments designed to inhibit host photosynthesis, resulted in lower estimated growth and depressed C and N-2 fixation, suggesting that despite the symbionts ability to fix their own C, they must still rely on their respective hosts for C. Single cell analysis indicated that up to 22% of assimilated C in the symbiont is derived from the host, whereas 78-91% of the host N is supplied from their symbionts. A size-dependent relationship is identified where larger cells have higher N-2 and C fixation, and only N-2 fixation was light dependent. Using the single cell measures, the N-rich phycosphere surrounding these symbioses was estimated and contributes directly and rapidly to the surface ocean rather than the mesopelagic, even at high estimated sinking velocities (<10 m d(-1)). Several eco-physiological parameters necessary for incorporating symbiotic N-2 fixing populations into larger basin scale biogeochemical models (i.e., N and C cycles) are provided

    Evidence of nitrification and denitrification in high and low microbial abundance sponges

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    Aerobic and anaerobic microbial key processes were quantified and compared to microbial numbers and morphological structure in Mediterranean sponges. Direct counts on histological sections stained with DAPI showed that sponges with high microbial abundances (HMA sponges) have a denser morphological structure with a reduced aquiferous system compared to low microbial abundance (LMA) sponges. In Dysidea avara, the LMA sponge, rates of nitrification and denitrification were higher than in the HMA sponge Chondrosia reniformis, while anaerobic ammonium oxidation and sulfate reduction were below detection in both species. This study shows that LMA sponges may host physiologically similar microbes with comparable or even higher metabolic rates than HMA sponges, and that anaerobic processes such as denitrification can be found both in HMA and LMA sponges. A higher concentration of microorganisms in the mesohyl of HMA compared to LMA sponges may indicate a stronger retention of and, hence, a possible benefit from associated microbes
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