3,602 research outputs found
Unusual distributions of long-chain alkenones and tetrahymanol from the highly alkaline Lake Van, Turkey
No full textLong-chain C37 to C40 alkenones with di-, tri-, and tetra-unsaturation are very abundant in sediment trap material and Holocene to Late Pleistocene core samples from the Earth's largest soda lake, Lake Van (Turkey). Thus, the known distribution range of these typical biomarkers for haptophyte microalgae is extended to highly alkaline environments. The observed unsaturation patterns differ strikingly from those found in open marine haptophytes and sediments by an enhanced relative abundance of the tetra-unsaturated compounds, especially the C37:4 methyl ketone. Their preponderance is suggested to be a facies marker pattern for lacustrine and marginal marine areas of sedimentation. Using published U37K calibrations, no reliable absolute temperatures were obtained for the Lake Van samples. Accordingly, marine sea surface temperature determinations based on long-chain alkenones should be applied with caution when a contribution of these compounds from coastal or nonmarine sources can not be excluded. The presence of tetrahymanol and gammacer-3-one in the Lake Van materials is attributed to organic matter contributions of ciliates. The relative abundance of long-chain alkenones and of tetrahymanol/gammacer-3-one is considered to reflect changes in the environmental conditions, in particular in the hydrological setting. We suggest that times of pronounced stagnation are recognised by very high tetrahymanol/gammacer-3-one concentrations together with drastically increased stanol/stenol ratios, and intervals of enhanced convection or of high freshwater input are characterised by high alkenone contributions
Microbial carbonate crusts - a key to the environmental analysis of fossil spongiolites?
No full textresearc
Professor Angela Shannon
No full textAngela Shannon shares her poetry with the Taylor community.
Angela Shannon is the author of Singing the Bones Together, a 2004 Minnesota Book Awards Finalist. She teaches English at Bethel University. Her work has been published in journals, textbooks, and anthologies, including TriQuarterly, Ploughshares, Where One Ends Another Begins: 150 Years of Minnesota Poetry, and Beyond the Frontier: African American Poetry for the 21st Century. Her choreopoem Root Woman premiered at the Fleetwood-Jourdain Theater in Evanston, Ill
Angela Shanté : 2022 Irma Black Award Silver Medal Acceptance Speech
No full textAuthor Angela Shanté gives an acceptance speech for When My Cousins Come to Town, illustrated by Keisha Morris (West Margin Press)https://educate.bankstreet.edu/irma_black_awards/1004/thumbnail.jp
The Family History of Angela Ruth Weidert
No full textAngela Ruth Weidert authored this family history as part of the course requirements for HIST 550/700 Your Family in History offered online in Spring 2018 and was submitted to the Pittsburg State University Digital Commons. Please contact the author directly with any questions or comments: [email protected]
Mid-chain branched alkanoic acids from "living fossil" demosponges: a link to ancient sedimentary lipids?
No full textThe lipid assemblages of the "living fossil" stromatoporoid Astrosclera willeyana (Great Barrier Reet) and the demosponge Agelas aroides (Mediterranean Sea) were investigated. Large amounts of branched carboxylic acids are present in the sponges studied. These compounds include terminally branched carboxylic acids (isa -/anteisa-) and abundant mid-chain branched carboxylic acids (MBCA) wh ich are characterized by an intriguing variety of structural isomers present in the C 15- C25 range. The most prominent MBCA are comprised of isomeric methylhexadecanoic acids and methyloctadecanoic acids. A second cluster of MBCA includes methyldocosanoic acids and methyltetracosanoic acids, but other homologues are also present. Methyl branching points were generally observed between the w5- and w9-positions. These complex isomeric mixtures apparently derive from symbiotic bacteria living exclusively in demosponges. Comparison with hydrocarbon compositions of ancient carbonates reveals evidence that the MBCA found are potential lipid precursors of mid-chain branched monomethylalkanes often observed in fossil sediments and oils. As a working hypo thesis, we suggest that their bacterial source organisms have been widespread in the geological past, and are found " inherited" in the protective environment of distinctive sponge hosts in recent marine ecosystems. Furthermore, both sponges contain abundant linear, longchain C24- C26 dienoic "demospongic" acids. The demospongic acid distribution and the presence of phytanic acid in A. willeyana match the patterns found in A. aroides and other members of the Agelasida. These findings confirm the systematic position of A. willeyana within this demosponge taxon
Materia-autore = Author-Matter
No full textThe etymology of the word author refers to an act of creation, an act of augmentation, from the Latin verb augere. Author instantiates creation, the expansion of the pre-existing. In 1967 Roland Barthes declared the death of the author in his famous essay to state once more that the crisis is that of the author as a single subjectivity and as a term that condenses prestige, undermined by the de-subjectivation strategies of automatism, fortuity and fragmentation of the historical avant-gardes, as well as by the machinic act and by the reproducibility of the second avant-gardes.
Fifty years after Barthes’ paradigmatic formula, this lack of authorship appears to be a successful brand. The ten- sions between the anomie of matter, the law that establishes authorship and the economy that makes the work pos- sible, invoke discordant perspectives. Artists make the self-destruction of their work the real work, and appeal is made for the demolition of architectures, whether by a recognised author or not, in order to re-design, or better still, re-claim the territory. Artificial intelligence consolidates its logics and its design by progressively shedding human ingenuity. The space of criticism becomes, finally, increasingly ephemeral. However, there is an acceptation of criti- cism that is, rather than an individual ‘signature’, an exploration and explanation of how design makes theory.
The binomial author-matter seeks to mark these tensions and contradictions: the featured term author is main- tained to underline the persistence of that prestigious subjectivity, at the very moment when the rhetoric of “mat- ter as an author” promises other forms of authorship
Giussani Sansoni, Angela
No full textLa scheda ricostruisce la vita e l'apporto della scrittrice Angela Giussani Sansoni alla letteratura per l'infanzia.The headword explains the biography and the contribution of the author Angela Giussani Sansoni to the children's literature
Mid-chain branched alkanoic acids from "living fossil" demosponges: a link to ancient sedimentary lipids?
No full textThe lipid assemblages of the "living fossil" stromatoporoid Astrosclera willeyana (Great Barrier Reet) and the demosponge Agelas aroides (Mediterranean Sea) were investigated. Large amounts of branched carboxylic acids are present in the sponges studied. These compounds include terminally branched carboxylic acids (isa -/anteisa-) and abundant mid-chain branched carboxylic acids (MBCA) wh ich are characterized by an intriguing variety of structural isomers present in the C 15- C25 range. The most prominent MBCA are comprised of isomeric methylhexadecanoic acids and methyloctadecanoic acids. A second cluster of MBCA includes methyldocosanoic acids and methyltetracosanoic acids, but other homologues are also present. Methyl branching points were generally observed between the w5- and w9-positions. These complex isomeric mixtures apparently derive from symbiotic bacteria living exclusively in demosponges. Comparison with hydrocarbon compositions of ancient carbonates reveals evidence that the MBCA found are potential lipid precursors of mid-chain branched monomethylalkanes often observed in fossil sediments and oils. As a working hypo thesis, we suggest that their bacterial source organisms have been widespread in the geological past, and are found " inherited" in the protective environment of distinctive sponge hosts in recent marine ecosystems. Furthermore, both sponges contain abundant linear, longchain C24- C26 dienoic "demospongic" acids. The demospongic acid distribution and the presence of phytanic acid in A. willeyana match the patterns found in A. aroides and other members of the Agelasida. These findings confirm the systematic position of A. willeyana within this demosponge taxon
Deliberation and journalism
No full textThe first chapter in 'International Journalism and Democracy' re-examines current ideas about the role of journalism in promoting democracy, introducing the concept of "deliberative journalism". 'Deliberation and Journalism' lists the ways in which journalists can assist deliberation and politics in communities around the world. The chapter defines deliberation as a specific form of conversation that precedes and promotes decision-making and action by members of a community. The author recognises the difficulty of engaging in deliberation in communities that are divided by different interests, identities, backgrounds, resources and needs. She provides examples of strategies that journalists can use to encourage inclusive and productive deliberation in the face of community diversity.\ud
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The chapter introduces examples of types of deliberative journalism that have emerged around the globe. These include strategies that have been sometimes been labeled as public journalism, civic journalism, peace journalism, development journalism, citizen journalism, the street press, community journalism, environmental journalism, and social entrepreneurism. The chapter also includes models of journalism that have not yet been given any particular name. Although the book identifies problems surrounding the theory and practice of these forms of journalism, the author notes that this is to be expected. Most models of deliberative journalism are relatively new, with none being more than a few decades old. The author concludes that resolution of these problems will only occur incrementally
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