967 research outputs found
The precautionary principle at work: The case of neonicotinoids and the health of bees
In recent years, scientists have noted a decline in the health of bee populations. Whereas a whole host of possible causes have been identified, it is the use of pesticides in agricultureâspecifically the use of neonicotinoidsâthat has warranted some investigation. The scientific evidence of their impact on the health of bees remains debated. This article examines how the UK Government has responded to the decline in bee populations and the apparent link to neonicotinoids. While notionally committed to deploying the Precautionary Principle in such instances, the government has tended to err more on âsound scienceâ as a policymaking tool. Early evidence indicates that the government used the latter initially but has become more amenable to utilising a precautionary approach recently. Whether this can be attributed to an embrace of the Precautionary Principle, or simply a change caused by the installation of a new Secretary of State for the Environment, is open to interpretation
AutoTuner: high fidelity and robust parameter selection for metabolomics data processing
© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in McLean, C., & Kujawinski, E. B. AutoTuner: high fidelity and robust parameter selection for metabolomics data processing. Analytical Chemistry, 92(8), (2020): 5724-5732, doi:10.1021/acs.analchem.9b04804.Untargeted metabolomics experiments provide a snapshot of cellular metabolism but remain challenging to interpret due to the computational complexity involved in data processing and analysis. Prior to any interpretation, raw data must be processed to remove noise and to align mass-spectral peaks across samples. This step requires selection of dataset-specific parameters, as erroneous parameters can result in noise inflation. While several algorithms exist to automate parameter selection, each depends on gradient descent optimization functions. In contrast, our new parameter optimization algorithm, AutoTuner, obtains parameter estimates from raw data in a single step as opposed to many iterations. Here, we tested the accuracy and the run-time of AutoTuner in comparison to isotopologue parameter optimization (IPO), the most commonly used parameter selection tool, and compared the resulting parametersâ influence on the properties of feature tables after processing. We performed a Monte Carlo experiment to test the robustness of AutoTuner parameter selection and found that AutoTuner generated similar parameter estimates from random subsets of samples. We conclude that AutoTuner is a desirable alternative to existing tools, because it is scalable, highly robust, and very fast (âŒ100â1000Ă speed improvement from other algorithms going from days to minutes). AutoTuner is freely available as an R package through BioConductor.We thank Titus Brown and Ben Temperton for advice on the algorithm validation, Arthur Eschenlauer for constructive feedback on the software design, Krista Longnecker for continuous support and discussions, Gabriel Leventhal for mathematics advice, the users of AutoTuner for debugging help through Github, and David Angeles-Albores and two anonymous reviewers for critical feedback on the manuscript. Funding support included the National GEM Consortium and NSF graduate research program fellowships (C.M.) and grants from the MIT Microbiome Center (Award 6936800, E.B.K.) and the Simons Foundation (Award ID #509034, E.B.K.)
A metabolic lens on phytoplankton physiology
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemical Oceanography at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2021.Phytoplankton are communities of diverse groups of prokaryotic and eukaryotic single-celled organisms responsible for nearly 50% of global primary production. The relative abundance of individual groups changes dynamically in response to environmental perturbations. Recent studies suggest that such changes are primarily driven by the distinct physiological responses employed by each group towards a particular perturbation. Although knowledge of some of these responses has come to light in recent years, many aspects of their metabolisms remain unknown. We attempt to address this gap by studying the metabolism of several phytoplankton groups using metabolomics. Firstly, we developed a method to enhance the analysis of untargeted metabolomics data. Secondly, we constructed two conceptual models describing how metabolism of the raphidophyte Heterosigma akashiwo responds to phosphorus and nitrogen stress. These conceptual models revealed several new stress response mechanisms not previously reported in other phytoplankton. Finally, we compared the metabolic changes of several distinct phytoplankton groups to uncover possible adaptation and acclimations that distinguish them. This analysis revealed several pathways and metabolites that represent the studied groups. The contributions of these pathways and metabolites towards physiology may support the ecological fitness of these organisms.None of this work would have been possible without a variety of funding sources. I was supported for three years by a National Science Foundation Graduate Research Fellowship and one year with a GEM fellowship. The research was carried out with grants from the MIT Microbiome Center (Award ID #6936800, EBK), the Simons Foundation (Award ID #509034, EBK), the Gordon and Betty Moore Foundation (Award ID #3304 EBK), the National Science Foundation (Award ID #OCE-0619608 to EBK and OCE-1057447 to EBK and MCKS) and the WHOI Ocean Ventures Fund
The Growth of the Anti-Transgender Movement in the United Kingdom. The Silent Radicalization of the British Electorate
This article examines the development of anti-transgender debates within the United Kingdom, which have gained traction due to proposed amendments to the countryâs Gender Recognition Act (GRA). A group of determined lobby groups, taking their lead from like-minded organizations in the United States, has protested vigorously against the proposed changes to the GRA, especially with respect to âsingle-sex spacesâ. As a result of this furor, the lives of transgender people have become the subject of open debate. Trans people now see their legitimacy questioned, and their ability to access services increasingly being placed under the microscope. This article argues that the literature on radicalization â developed in response to domestic terrorism â can explain these developments. UK lobby groups are successfully pushing a radical agenda to deny the basic rights of trans people, and are doing so under the cover of âfree speechâ â a sacrosanct element of life in Anglo-Saxon countries
Calibration and alignment of metrology system for the Nuclear Spectroscopic Telescope Array mission
A metrology system to measure the on-orbit movement of a ten
meter mast has been built for the Nuclear Spectroscopic Telescope Array (NuSTAR) x-ray observatory. In this paper, the metrology system is described, and the performance is measured. The laser beam stability is discussed in detail. Pre-launch alignment and calibration are also described. The invisible infrared laser beams must be aligned to their corresponding detectors without deploying the telescope in Earthâs gravity. Finally, a possible method for in-flight calibration of the metrology system is described
Evaluation of the South Australian default 50 km/h speed limit
On 1 March 2003 the default urban speed limit in South Australia was reduced from 60 km/h to 50 km/h. On-road speeds just before the default limit was introduced were compared with speeds a year later. The numbers of casualty crashes and casualties in the year before the default limit was introduced were compared with the corresponding numbers in the first year that the default limit was in effect. On roads where the speed limit was reduced from 60 km/h to 50 km/h, average vehicle speeds decreased by 2.3 km/h and casualties by 24 per cent. On roads where the speed limit remained at 60 km/h, average vehicle speeds decreased by 0.9 km/h and casualties by 7 per cent.C.N. Kloeden, J.E. Woolley and A.J. McLea
Front side window tinting visual light transmittance requirements
The Australasian Branch of the International Window Film Association has lobbied for approval for tinting of front side windows of cars down to a level such that 35% of incident visible light is transmitted through to the driver. South Australia currently has a minimum level of visible light transmittance of 70% for front side windows. This Report explores the safety implications of the proposed greater levels of tinting on front side windows and concludes that road safety would be adversely affected by allowing such a move.M.R.J. Baldock, A.J. McLean and C.N.Kloede
Gaining insights from Candida biofilm heterogeneity: one size does not fit all
Despite their clinical significance and substantial human health burden, fungal infections remain relatively under-appreciated. The widespread overuse of antibiotics and the increasing requirement for indwelling medical devices provides an opportunistic potential for the overgrowth and colonization of pathogenic Candida species on both biological and inert substrates. Indeed, it is now widely recognized that biofilms are a highly important part of their virulence repertoire. Candida albicans is regarded as the primary fungal biofilm forming species, yet there is also increasing interest and growing body of evidence for non-Candida albicans species (NCAS) biofilms, and interkingdom biofilm interactions. C. albicans biofilms are heterogeneous structures by definition, existing as three-dimensional populations of yeast, pseudo-hyphae, and hyphae, embedded within a self-produced extracellular matrix. Classical molecular approaches, driven by extensive studies of laboratory strains and mutants, have enhanced our knowledge and understanding of how these complex communities develop, thrive, and cause host-mediated damage. Yet our clinical observations tell a different story, with differential patient responses potentially due to inherent biological heterogeneity from specific clinical isolates associated with their infections. This review explores some of the recent advances made in an attempt to explore the importance of working with clinical isolates, and what this has taught us
TOTAL REPLACEMENT OF FISHMEAL WITH AN ORGANICALLY CERTIFIED YEASTâBASED PROTEIN IN PACIFIC WHITE SHRIMP (Litopenaeus Vannamei) DIETS: LABORATORY AND FIELD TRIALS
The feasibility of totally replacing the fishmeal component of marine shrimp (Litopenaeus vannamei) diets was examined both in the laboratory setting and during a fullâscale commercial trial. Animals were fed either a traditional fishmealâbased diet or one in which complete replacement of fishmeal, on a per protein basis, was manufactured using a yeastâbased product, NuProÂź. Laboratory studies determined that irrespective of diet fed, no difference in shrimp performance (weight gain, survival and SGR) occurred. A field trial was thus activated to determine whether labâscale studies were transferable to the commercial setting. Trials were conducted in earthen ponds from midâJune to early November 2005. Ponds were initially stocked with PL12â16 shrimp at a rate of 100,000 per hectare. At trial end, ponds receiving the NuProÂźâbased feed had equivalent growth to that of shrimp fed the traditional, fishmealâbased diet. Percent increase in weight from initial values and survival for the NuProÂź ponds was 296, 269 and 275%, and 78, 76 and 85% respectively, whereas that for the fishmealâbased diet was 305% and 80% respectively. Noteworthy was that within pond size variation of L. vannamei was lower in NuProÂź fed animals (±2.3 g) when compared against animals receiving the traditional feed (±4.1 g). Overall observations from the field trial indicate the importance of the »bioreactor« pond with respect to the supply of energy to sustain shrimp growth potential
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