2,906 research outputs found

    Intracellular metabolites in marine microorganisms during an experiment evaluating microbial mortality

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    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Longnecker, K., & Kujawinski, E. B. Intracellular metabolites in marine microorganisms during an experiment evaluating microbial mortality. Metabolites, 10(3), (2020): 105, doi: 10.3390/metabo10030105.Metabolomics is a tool with immense potential for providing insight into the impact of biological processes on the environment. Here, we used metabolomics methods to characterize intracellular metabolites within marine microorganisms during a manipulation experiment that was designed to test the impact of two sources of microbial mortality, protozoan grazing and viral lysis. Intracellular metabolites were analyzed with targeted and untargeted mass spectrometry methods. The treatment with reduced viral mortality showed the largest changes in metabolite concentrations, although there were organic compounds that shifted when the impact of protozoan grazers was reduced. Intracellular concentrations of guanine, phenylalanine, glutamic acid, and ectoine presented significant responses to changes in the source of mortality. Unexpectedly, variability in metabolite concentrations were not accompanied by increases in microbial abundance which indicates that marine microorganisms altered their internal organic carbon stores without changes in biomass or microbial growth. We used Weighted Correlation Network Analysis (WGCNA) to identify correlations between the targeted and untargeted mass spectrometry data. This analysis revealed multiple unknown organic compounds were correlated with compatible solutes, also called osmolytes or chemical chaperones, which emphasizes the dominant role of compatible solutes in marine microorganisms.This research was funded by the US National Science Foundation (OCE-1154320 to EBK and KL, OCE-1634016 to EBK) and WHOI’s Ocean Life Institute (to EBK and KL). The mass spectrometry samples were analyzed at the WHOI FT-MS Users’ Facility with instrumentation funded by the National Science Foundation (OCE-0619608 and OCE-1058448)

    Electronic gating circuit and ultraviolet laser excitation permit improved dosimeter sensitivity

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    Standard dosimeter reader, modified by adding an electronic gating circuit to trigger the intensity level photomultiplier, increases readout sensitivity of photoluminescent dosimeter systems. The gating circuit is controlled by a second photomultiplier which senses a short ultraviolet pulse from a laser used to excite the dosimeter

    Dissolved organic matter in newly formed sea ice and surface seawater

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    © The Author(s), 2015. This is the author's version of the work and is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Geochimica et Cosmochimica Acta 171 (2015): 39-49, doi:10.1016/j.gca.2015.08.014.Changes in sea ice in the Arctic will have ramifications on regional and global carbon cycling. Research to date has primarily focused on the regional impacts to biological activity and global impacts on atmospheric processes. The current project considers the molecular-level composition of organic carbon within sea ice compared to the organic matter in seawater. The project revealed that the composition of organic matter within sea ice was more variable than the composition of organic matter within the surface ocean. Furthermore, sea ice samples presented two distinct patterns in the composition of organic matter with a portion of the sea ice samples containing protein-like organic matter. Yet, the samples were collected in the early winter period when little biological activity is expected. Thus, one hypothesis is that physical processes acting during the formation of sea ice selectively transferred organic matter from seawater into sea ice. The present project expands our understanding of dissolved organic matter in sea ice and surface seawater and thereby increases our knowledge of carbon cycling in polar regions.This research was funded by a grant from WHOI’s Arctic Research Initiative to KL.2016-09-0

    Teacher practices with adaptive math technology: Sitting in the driver’s seat of a self-driving car

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    The 21st century has seen adaptive math technology (AMT), often formatted as digital game-based learning, integrated into a greater number of elementary classrooms as students have more access to devices than ever before. This study explores the practices of power users, teachers who are highly effective users and integrators of that technology. Specifically, the top ten percent of users of the adaptive math program, DreamBox, were surveyed (n = 117) about their practices and routines when integrating the AMT. The results of this study contribute to teacher practices for integrating this technology into the K-5 classroom. The findings show teachers with the highest amount of average student growth deliberately schedule time daily for program use, have time and/or lesson requirements for their students, give rewards (often in the form of public acknowledgment), and hold their students accountable for their progress in learning. When these power users view individual student data on the program’s dashboard, the practices they engage in most often are viewing the student’s total amount of time using the program and lessons completed. When viewing the class as a whole, they view lessons completed and total standards completed. The teachers reported they use the AMT most often for student review of content from the current grade and additional practice of that content, essentially pairing the lessons students engage in the program with what they are presently teaching. This study establishes the practices of highly effective teachers for using AMT in the classroom as: (1) pairing lessons with current content being taught, (2) having daily scheduled time for AMT, (3) time/lesson requirement for students, (4) a system of rewards & accountability, (5) assigning lessons to fill in gaps & enrichment, and (6) identifying students struggling & holding help sessions

    A Study of the Coccinellidae of Iowa

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    The writer has collected Coccinellids in several localities of Iowa for some time, and also has exchanged specimens with collectors in this and other parts of the country. The specimens have been classified and are in the collection of Iowa Wesleyan College

    The Old Soul of Design

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    Can the critique of modern dwelling be resolved through the restoration and integration of old architecture and the stories it carries? And can these pieces of historic architecture be reshaped to bridge time and place? Following the critique given by several philosophers and cultural critics, there is a distinct neglect for the stories of historic architecture which contributes to the disconcerting attempt to dwell within our modern cities. Considering the German philosopher, Martin Heidegger?s, critique in his essay Building Dwelling Thinking, is it possible that our technology has advanced so far that we have forgotten what came before us, that which allowed us to dwell in a place in a meaningful way

    Boots on the Ground: Use and Implications of War Metaphors in a Top Team

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    This paper describes the use and implications of war and military metaphors shared by a top management team working in the defense industry. The team used war metaphors pervasively to make meaning of the ambiguity and uncertainty in its environment. Five categories of war metaphors and action verbs were found. Findings from this study suggest the team used metaphors to structure and communicate abstract ideas and experiences, highlight or hide aspects of the work environment, unite team members, lead their organization, and maintain their warlike culture. Further findings demonstrate how the team constructed and maintained metaphors individually, intersubjectively, unreflectively, and in ongoing dialogue. The implications of this study provide insights into how a top management team used metaphor to define its perception of itself and its environment and in so doing, to manage its relationships within that environment

    Boots on the Ground: Use and Implications of War Metaphors in a Top Team

    Get PDF
    This paper describes the use and implications of war and military metaphors shared by a top management team working in the defense industry. The team used war metaphors pervasively to make meaning of the ambiguity and uncertainty in its environment. Five categories of war metaphors and action verbs were found. Findings from this study suggest the team used metaphors to structure and communicate abstract ideas and experiences, highlight or hide aspects of the work environment, unite team members, lead their organization, and maintain their warlike culture. Further findings demonstrate how the team constructed and maintained metaphors individually, intersubjectively, unreflectively, and in ongoing dialogue. The implications of this study provide insights into how a top management team used metaphor to define its perception of itself and its environment and in so doing, to manage its relationships within that environment
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