18 research outputs found

    Robust estimation of bacterial cell count from optical density

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    Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

    Taking state of biodiversity reporting into the information age – A South African perspective

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    South Africa’s National Biodiversity Assessment (NBA) is the primary tool for monitoring and reporting on the state of biodiversity, with a focus on spatial information and key indicators. The NBA distills information that informs policies and strategies, meets national and international reporting requirements, and helps prioritize limited resources for managing and conserving biodiversity. The three previous versions of the NBA (2004, 2011 and 2018) are in the form of detailed thematic technical reports and a synthesis report, served on a simple, static web page. Selected spatial products from the report are available via a dedicated web platform (http://nba.sanbi.org.za/). While all methods and data are clearly described in the technical reports, most of the underlying analyses are inaccessible, lacking reproducibility and transparency. This makes iterative updates to indicators or metrics challenging and inefficient, complicates version control, and exacerbates the risk of capacity, knowledge and data loss during staff turnover. To move the assessment process into the information age we aim to develop well documented and reproducible workflows, and to serve the indicators and their accompanying synthesis on an interactive web platform that facilitates uptake. Achieving these aims will deliver efficiency, greater transparency and trust in future NBA products and will strengthen communication and engagement with the content by the many different users of those products. While these visions will not be realized overnight, the skills and systems required to achieve them can be adaptively built towards an improved NBA that better serves the needs of our society

    Personal Attributes and Latino Voting Behavior in Congress

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    Objective. Researchers have long examined the nature of representation, paying particular attention to the dynamics of descriptive and substantive representation in racial and ethnic communities. The objective of this article is to determine the extent to which personal attributes influence the voting behavior of Latino members of Congress. Methods. We test the relationship between legislator's personal attributes and Poole and Rosenthal's DW‐NOMINATE scores for Latino members of the 101st–108th Congresses. Results. After controlling for institutional and electoral factors, results show that education, gender, nativity, and generation have significant effects on Latino legislators' voting behavior. Religion and national origin appear not to have an effect. Conclusions. This analysis shows that personal attributes predict Latino congressional voting even when controlling for district and institutional factors. As such, this study demonstrates that Latino legislators have in‐group differences and therefore should not be considered a monolithic group

    ESICM guidelines on acute respiratory distress syndrome: definition, phenotyping and respiratory support strategies

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    The aim of these guidelines is to update the 2017 clinical practice guideline (CPG) of the European Society of Intensive Care Medicine (ESICM). The scope of this CPG is limited to adult patients and to non-pharmacological respiratory support strategies across different aspects of acute respiratory distress syndrome (ARDS), including ARDS due to coronavirus disease 2019 (COVID-19). These guidelines were formulated by an international panel of clinical experts, one methodologist and patients’ representatives on behalf of the ESICM. The review was conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement recommendations. We followed the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess the certainty of evidence and grade recommendations and the quality of reporting of each study based on the EQUATOR (Enhancing the QUAlity and Transparency Of health Research) network guidelines. The CPG addressed 21 questions and formulates 21 recommendations on the following domains: (1) definition; (2) phenotyping, and respiratory support strategies including (3) high-flow nasal cannula oxygen (HFNO); (4) non-invasive ventilation (NIV); (5) tidal volume setting; (6) positive end-expiratory pressure (PEEP) and recruitment maneuvers (RM); (7) prone positioning; (8) neuromuscular blockade, and (9) extracorporeal life support (ECLS). In addition, the CPG includes expert opinion on clinical practice and identifies the areas of future research
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