1,656 research outputs found

    A microfluidic platform for quantitative analysis of single mycobacteria cells

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    Thesis (Ph.D.)--Boston UniversityMycobacterium tuberculosis (MTB), the causative agent of tuberculosis (TB), is the leading bacterial cause of death worldwide. A significant barrier to global MTB eradication is 'latent' TB infection, where MTB persists in the human host in a metabolically dormant and highly drug-tolerant state. Latently infected individuals constitute a vast global reservoir of disease (~2 billion people worldwide), and the heightened drug tolerance of dormant MTB necessitates long antibiotic treatments (up to 9 months of combination antibiotic therapy). MTB dormancy is thought to be the result of an adaptive response to host-induced stresses, involving coordinated transcriptional regulation of hundreds of genes as well as numerous metabolic changes. Currently, our understanding of this process is limited by a lack of tools for studying dynamic behavior in single cells. Gene regulation is a dynamic phenomenon that occurs within each cell individually, but many assays rely on steady-state measurements of a population average and thus fail to capture important information about the dynamics of cellular behavior. Additionally, cell-to-cell phenotypic variation has been identified as a key source of microbial drug tolerance, further highlighting the need for single-cell studies. To address this need, we developed a microfluidic platform to study Mycobacteria species at the single-cell level. This platform enables on-chip culture and fluorescent imaging of live cells in precisely controlled conditions, and can thus be used to study dynamic processes within single cells as well as phenotypic heterogeneity across a cellular population. We used this platform to obtain diverse new insights about mycobacterial biology, using the fast-growing mycobacterium M smegmatis. 1) We directly observed gene regulation by the transcription factor KstR in single cells, confirming regulatory interactions that had been predicted computationally. 2)We analyzed morphology, growth, and division data across hundreds of single cells and found that cell division in Mycobacteria is governed using size-based, rather than time-based, control mechanisms. 3) We found that individual cells exhibit considerable differences in their responses to antibiotic stress, and that these differences have implications for cellular survival

    His story/her story: A dialogue about including men and masculinities in the women’s studies curriculum

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    The article discusses the issue of inclusion of men and masculinities in the Women\u27s Studies curriculum. Women\u27s Studies programs were started to compensate for the male domination in the academics. Women\u27s Studies presented a platform where scholarship for women was produced and taken seriously, female students and faculty could find their say or voice, and theoretical investigations required for the advancement of the aims of the women\u27s movement could take place. If the academy as a whole does not sufficiently integrate Women\u27s Studies into the curriculum, integrating Men\u27s Studies into Women\u27s Studies might end up further marginalizing Women\u27s Studies by decreasing the number of classroom hours students spend engaging women\u27s lives and feminist scholarship. Such an integration would presents an another form of male privilege, with men manipulating their way into the only branch of scholarship that has consistently focused on women. On a ground level, feminist scholars are apprehensive that a move from a Women\u27s Studies program to a Gender Studies program will reduce the political aspect of women\u27s programs

    Jean Epstein

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    Filmmaker and theoretician Jean Epstein profoundly influenced film practice, criticism and reception in France during the 1920s and well beyond. His work not only forms the crux of the debates of his time, but also remains key to understanding later developments in film practice and theory. Epstein' s film criticism is among the most wide-ranging, provocative and poetic writing about cinema and his often breathtaking films offer insights into cinema and the experience of modernity. This collection - the first comprehensive study in English of Epstein's far-reaching influence - arrives as several of the concerns most central to Epstein' s work are being reexamined, including theories of perception, realism, and the relationship between cinema and other arts. The volume also includes new translations from every major theoretical work Epstein published, presenting the widest possible historical and contextual range of Epstein' s work, from his beginnings as a biology student and literary critic to his late film projects and posthumously published writings.Filmmaker en -theoreticus Jean Epstein beïnvloedde sterk de filmpraktijk, -kritiek en -receptie in Frankrijk en ver daarbuiten tijdens de jaren twintig van de vorige eeuw. Zijn werk vormde niet alleen de kern van de debatten in die tijd, maar is ook een sleutel voor het begrijpen van latere ontwikkelingen in de filmpraktijk en -theorie. Epsteins filmkritieken zijn uiteenlopende, uitdagende en poëtisch geschreven teksten, en zijn vaak adembenemende films bieden belangrijke en moderne inzichten in de cinema. Dit boek verschijnt op het moment dat een aantal van de thema' s die centraal staan in het werk van Epstein opnieuw wordt onderzocht, met inbegrip van de theorie van de waarneming, realisme en de relatie tussen cinema en de andere kunsten. De kritische essays vormen een waardevolle inleiding tot het creatieve oeuvre van Epstein

    Pathways of Anaerobic Carbon Cycling Across an Ombrotrophic–Minerotrophic Peatland Gradient

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    Peatland soils represent globally significant stores of carbon, and understanding carbon cycling pathways in these ecosystems has important implications for global climate change. We measured aceticlastic and autotrophic methanogenesis, sulfate reduction, denitrification, and iron reduction in a bog, an intermediate fen, and a rich fen in the Upper Peninsula of Michigan for one growing season. In 3-d anaerobic incubations of slurried peat, denitrification and iron reduction were minor components of anaerobic carbon mineralization. Experiments using 14C-labeled methanogenic substrates showed that methanogenesis in these peatlands was primarily through the aceticlastic pathway, except early in the growing season in more ombrotrophic peatlands, where the autotrophic pathway was dominant or codominant. Overall, methane production was responsible for 3-70% of anaerobic carbon mineralization. Sulfate reduction accounted for 0-26% of anaerobic carbon mineralization, suggesting a rapid turnover of a very small sulfate pool. A large percentage of anaerobic carbon mineralization (from 29% to 85%) was unexplained by any measured process, which could have resulted from fermentation or possibly from the use of organic molecules (e.g., humic acids) as alternative electron acceptors

    Solid-Phase Organic Matter Reduction Regulates Anaerobic Decomposition in Bog Soil

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    Peatlands store globally significant amounts of carbon and are important sources of the greenhouse gas methane (CH4) to the atmosphere. However, for reasons which are not well understood, many peatland soils produce smaller amounts of CH4 than theoretically predicted, and carbon dioxide (CO2) produced during anaerobic decomposition in peatland soils cannot be accounted for by commonly measured microbial processes. Here we show that the reduction of solid-phase organic matter (i.e., humic substances) suppresses CH4 production in a bog soil and can be responsible for 33–61% of the total carbon mineralization in this soil. These results demonstrate that the reduction of organic matter is a key component of anaerobic decomposition in peatlands, and is at least partially responsible for their low CH4 production. Thus, organic matter reduction may be a key regulator of how peatlands respond to ongoing global change

    Jean Epstein

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    Filmmaker and theoretician Jean Epstein profoundly influenced film practice, criticism and reception in France during the 1920s and well beyond. His work not only forms the crux of the debates of his time, but also remains key to understanding later developments in film practice and theory. Epstein' s film criticism is among the most wide-ranging, provocative and poetic writing about cinema and his often breathtaking films offer insights into cinema and the experience of modernity. This collection - the first comprehensive study in English of Epstein's far-reaching influence - arrives as several of the concerns most central to Epstein' s work are being reexamined, including theories of perception, realism, and the relationship between cinema and other arts. The volume also includes new translations from every major theoretical work Epstein published, presenting the widest possible historical and contextual range of Epstein' s work, from his beginnings as a biology student and literary critic to his late film projects and posthumously published writings

    Personality type differences between Ph.D. climate researchers and the general public: implications for effective communication

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    Effectively communicating the complexity of climate change to the public is an important goal for the climate change research community, particularly for those of us who receive public funds. The challenge of communicating the science of climate change will be reduced if climate change researchers consider the links between personality types, communication tendencies and learning preferences. Jungian personality type is one of many factors related to an individual’s preferred style of taking in and processing information, i.e., preferred communication style. In this paper, we demonstrate that the Jungian personality type profile of interdisciplinary, early career climate researchers is significantly different from that of the general population in the United States. In particular, Ph.D. climate researchers tend towards Intuition and focus on theories and the “big picture”, while the U.S. general population tends towards Sensing and focuses on concrete examples and experience. There are other differences as well in the way the general public as a group prefers to take in information, make decisions, and deal with the outer world, compared with the average interdisciplinary climate scientist. These differences have important implications for communication between these two groups. We suggest that climate researchers will be more effective in conveying their messages if they are aware of their own personality type and potential differences in preferred learning and communication styles between themselves and the general public (and other specific audiences), and use this knowledge to more effectively target their audience
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