125 research outputs found

    Column CO2 Measurement From an Airborne Solid-State Double-Pulsed 2-Micron Integrated Path Differential Absorption Lidar

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    NASA LaRC is developing and integrating a double-Pulsed 2-micron direct detection IPDA lidar for CO2 column measurement from an airborne platform. The presentation will describe the development of the 2-micrometers IPDA lidar system and present the airborne measurement of column CO2 and will compare to in-situ measurement for various ground target of different reflectivity

    Damping and decoherence of a nanomechanical resonator due to a few two level systems

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    We consider a quantum model of a nanomechanical flexing beam resonator interacting with a bath comprising a few damped tunneling two level systems (TLS's). In contrast with a resonator interacting bilinearly with an ohmic free oscillator bath (modeling clamping loss, for example), the mechanical resonator damping is amplitude dependent, while the decoherence of quantum superpositions of mechanical position states depends only weakly on their spatial separation

    Selection for antimicrobial resistance is reduced when embedded in a natural microbial community

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    This is the final version. Available from Springer Nature via the DOI in this record.Antibiotic resistance has emerged as one of the most pressing, global threats to public health. In single-species experiments selection for antibiotic resistance occurs at very low antibiotic concentrations. However, it is unclear how far these findings can be extrapolated to natural environments, where species are embedded within complex communities. We competed isogenic strains of Escherichia coli, differing exclusively in a single chromosomal resistance determinant, in the presence and absence of a pig faecal microbial community across a gradient of antibiotic concentration for two relevant antibiotics: gentamicin and kanamycin. We show that the minimal selective concentration was increased by more than one order of magnitude for both antibiotics when embedded in the community. We identified two general mechanisms were responsible for the increase in minimal selective concentration: an increase in the cost of resistance and a protective effect of the community for the susceptible phenotype. These findings have implications for our understanding of the evolution and selection of antibiotic resistance, and can inform future risk assessment efforts on antibiotic concentrations.Medical Research Council (MRC)European Commissio

    Epigenetic mechanisms in virus-induced tumorigenesis

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    About 15–20% of human cancers worldwide have viral etiology. Emerging data clearly indicate that several human DNA and RNA viruses, such as human papillomavirus, Epstein–Barr virus, Kaposi’s sarcoma-associated herpesvirus, hepatitis B virus, hepatitis C virus, and human T-cell lymphotropic virus, contribute to cancer development. Human tumor-associated viruses have evolved multiple molecular mechanisms to disrupt specific cellular pathways to facilitate aberrant replication. Although oncogenic viruses belong to different families, their strategies in human cancer development show many similarities and involve viral-encoded oncoproteins targeting the key cellular proteins that regulate cell growth. Recent studies show that virus and host interactions also occur at the epigenetic level. In this review, we summarize the published information related to the interactions between viral proteins and epigenetic machinery which lead to alterations in the epigenetic landscape of the cell contributing to carcinogenesis

    Intersexuality and Trans-Identities within the Diversity Management Discourse

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    Within both the scientific discourse on workforce diversity, and diversity management practice, intersexuality and transgender issues have hitherto remained marginalized topics. This chapter gives an overview of the discourses on both phenomena, and proposes starting points for more inclusive organizational diversity management initiatives. It is shown that both topics represent different aspects of the category of "gender". The common practice of conceptually lumping together intersexuality, transgenderism, and sexual orientation can be seen as one important reason that intersexuality and transgenderism are rarely considered in organizational diversity management programs in terms of concrete action. Against this background, a modified, and more integrated approach to structuring the workforce alongside the different dimensions of diversity is proposed. It is shown that the categories of "biological sex and gender", "gender identity", and "sexual orientation" cannot be regarded as being separate from each other. They represent, rather, an interrelated organizational field of action that should be considered as being one interrelated topic for organizational diversity practices. This chapter derives this claim theoretically and discusses the consequences for organizational diversity management practices. For most organizations, this would mean a fundamental rethinking of their goals, in terms of workforce diversity, and the shaping of their diversity management programs

    Central pathways causing fatigue in neuro-inflammatory and autoimmune illnesses

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