891 research outputs found

    Paley, William: science and rhetoric in his natural theology

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    William Paley's Natural Theology is probably the nineteenth century's most well- known design argument. As such an influential book, it is almost expected that twentieth century intellectual historians should at least pay a footnote to it. In midst of all these studies about the impact of Natural Theology upon the nineteenth century, one key fact is forgotten: Natural Theology and its sources were written in the eighteenth century. It is the goal of this thesis to demonstrate that Paley's design argument must be compared to the intellectual climate of that time period. Chapters 1 and 2 outline the rhetorical argument and the tools that Paley used to persuade his polite eighteenth century audience. The majority of scientific sources and examples he used were well-known names and therefore implicitly contributed to the believability of his argument. Accordingly, chapters 3 and 4 investigate why Paley's scientific sources added credibility to Natural Theology. Chapters 5 and 6 examine the actual scientific data that Paley turned into examples for his design argument. Setting the rhetoric aside, what was the actual scientific picture communicated by his examples? In these chapters, we find that even though Paley argues against random change, he does support a morphological telic change—the development of a supplemental part based on a pre-existing, fixed body part. As every chapter of this thesis unfolds, it will become more apparent that Paley was an intellectual heir to the eighteenth century. He wrote in a polite manner and employed a body of standard eighteenth century natural philosophical knowledge. It is this context that must be addressed and seriously considered when studying the nineteenth century intellectual legacy of Natural Theology

    The 'ingenious' rev. Dr. John Walker: chemistry, mineralogy and geology in enlightenment Edinburgh (1740-1800)

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    Rev. Dr. John Walker (1731-1803) held the Regius Chair of Natural History in the University of Edinburgh's Medical School from 1779 until 1803. As a student of William Cullen, advisor to Lord Karnes and friend of Joseph Black, he went on to teach well over seven hundred students and was a founding member of the Royal Society of Edinburgh. This study uses his career to trace the course of the nascent earth sciences within the Medical School's local reality. It is based on the publications of Walker and his colleagues, and on the vast archive of his personal manuscripts, correspondence and lecture notes housed in the University of Edinburgh’s Special Collections. After Chapter 1's biographical introduction, Chapters 2 and 3 concentrate on his early chemical education and show that a principle-based form of experimental pharmacology laid the epistemological and methodological foundation for Edinburgh's interest in mineralogy. This is done by examining the Medical School's 1750s chemistry course in relation to Walker's early publications and then by detailing his mid-career tours and attempts at mineralogical taxonomy. Moving on to his time as Professor of Natural History, Chapters 4 and 5 excavate his 'fossil' sources and vocabulary and detail his 1797 mineralogical system. The final chapter gives an account of his geology lectures and how they were directly affected by his conception of chemistry and mineralogy; special attention is given to geological methodology, time, extraneous fossils and testimony taken from classical works. The conclusion proceeds to illustrate how histories interested in the 'forerunners' of the chemical revolution and/or the evolutionary paradigm ignore the large number of chemically trained industrialists and medical professionals who contributed to Enlightenment concepts of the earth's form and structure

    Connectivity of Markoff mod-p graphs and maximal divisors

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    Markoff mod-pp graphs are conjectured to be connected for all primes pp. In this paper, we use results of Chen and Bourgain, Gamburd, and Sarnak to confirm the conjecture for all p>3.448⋅10392p > 3.448\cdot10^{392}. We also provide a method that quickly verifies connectivity for many primes below this bound. In our study of Markoff mod-pp graphs we introduce the notion of \emph{maximal divisors} of a number. We prove sharp asymptotic and explicit upper bounds on the number of maximal divisors, which ultimately improves the Markoff graph pp-bound by roughly 140 orders of magnitude as compared with an approach using all divisors

    The Nature of Notebooks: How Enlightenment Schoolchildren Transformed the Tabula Rasa

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    John Locke's comparison of the mind to a blank piece of paper, the tabula rasa, was one of the most recognizable metaphors of the British Enlightenment. Though scholars embrace its impact on the arts, humanities, natural sciences, and social sciences, they seldom consider why the metaphor was so successful. Concentrating on the notebooks made and used by the schoolchildren of Enlightenment Scotland, this essay contends that the answer lies in the material and visual conditions that gave rise to the metaphor's usage. By the time students had finished school, they had learned to conceptualize the pages, the script, and the figures of their notebooks as indispensable learning tools that could be manipulated by scores of adaptable folding, writing, and drawing techniques. In this article, I reveal that historicizing the epistemology and manipulability of student manuscript culture makes it possible to see that the success of Locke's metaphor was founded on its appeal to everyday note-keeping activities performed by British schoolchildren

    The Genetic Links to anxiety and depression (GLAD) study: Online recruitment into the largest recontactable study of depression and anxiety

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    Background: Anxiety and depression are common, debilitating and costly. These disorders are influenced by multiple risk factors, from genes to psychological vulnerabilities and environmental stressors, but research is hampered by a lack of sufficiently large comprehensive studies. We are recruiting 40,000 individuals with lifetime depression or anxiety and broad assessment of risks to facilitate future research. Methods: The Genetic Links to Anxiety and Depression (GLAD) Study (www.gladstudy.org.uk) recruits individuals with depression or anxiety into the NIHR Mental Health BioResource. Participants invited to join the study (via media campaigns) provide demographic, environmental and genetic data, and consent for medical record linkage and recontact. Results: Online recruitment was effective; 42,531 participants consented and 27,776 completed the questionnaire by end of July 2019. Participants’ questionnaire data identified very high rates of recurrent depression, severe anxiety, and comorbidity. Participants reported high rates of treatment receipt. The age profile of the sample is biased toward young adults, with higher recruitment of females and the more educated, especially at younger ages. Discussion: This paper describes the study methodology and descriptive data for GLAD, which represents a large, recontactable resource that will enable future research into risks, outcomes, and treatment for anxiety and depression

    Mechanism of subunit interaction at ketosynthase-dehydratase junctions in trans-AT polyketide synthases

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    Modular polyketide synthases (PKSs) produce numerous structurally complex natural products with diverse applications in medicine and agriculture. They typically consist of several multienzyme subunits that utilize structurally-defined docking domains (DDs) at their N- and C-termini to ensure correct assembly into functional multi-protein complexes. Here we report a fundamentally different mechanism for subunit assembly in trans-AT modular PKSs at the junction between ketosynthase (KS) and dehydratase (DH) domains. This involves direct interaction of a largely unstructured docking domain (DD) at the C-terminus of the KS with the surface of the downstream DH. Acyl transfer assays and mechanism-based cross-linking established that the DD is required for the KS to communicate with the acyl carrier protein appended to the DH. Two distinct regions for binding of the DD to the DH were identified using NMR spectroscopy, carbene foot-printing and mutagenesis, providing a foundation for future elucidation of the molecular basis for interaction specificity

    Microchannel cooling for the LHCb VELO Upgrade I

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    The LHCb VELO Upgrade I, currently being installed for the 2022 start of LHC Run 3, uses silicon microchannel coolers with internally circulating bi-phase \cotwo for thermal control of hybrid pixel modules operating in vacuum. This is the largest scale application of this technology to date. Production of the microchannel coolers was completed in July 2019 and the assembly into cooling structures was completed in September 2021. This paper describes the R\&D path supporting the microchannel production and assembly and the motivation for the design choices. The microchannel coolers have excellent thermal peformance, low and uniform mass, no thermal expansion mismatch with the ASICs and are radiation hard. The fluidic and thermal performance is presented.Comment: 31 pages, 27 figure

    Global Carbon Budget 2022

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    Accurate assessment of anthropogenic carbon dioxide (CO2_2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesize data sets and methodologies to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2_2 emissions (EFOS_{FOS}) are based on energy statistics and cement production data, while emissions from land-use change (ELUC_{LUC}), mainly deforestation, are based on land use and land-use change data and bookkeeping models. Atmospheric CO2_2 concentration is measured directly, and its growth rate (GATM_{ATM}) is computed from the annual changes in concentration. The ocean CO2_2 sink (SOCEAN_{OCEAN}) is estimated with global ocean biogeochemistry models and observation-based data products. The terrestrial CO2_2 sink (SLAND_{LAND}) is estimated with dynamic global vegetation models. The resulting carbon budget imbalance (BIM_{IM}), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the year 2021, EFOS_{FOS} increased by 5.1 % relative to 2020, with fossil emissions at 10.1 ± 0.5 GtC yr−1^{−1} (9.9 ± 0.5 GtC yr−1^{−1} when the cement carbonation sink is included), and ELUC_{LUC} was 1.1 ± 0.7 GtC yr−1^{−1}, for a total anthropogenic CO2_2 emission (including the cement carbonation sink) of 10.9 ± 0.8 GtC yr−1^{−1} (40.0 ± 2.9 GtCO2_2). Also, for 2021, GATM_{ATM} was 5.2 ± 0.2 GtC yr−1^{−1} (2.5 ± 0.1 ppm yr−1^{−1}), SOCEAN_{OCEAN} was 2.9  ± 0.4 GtC yr−1^{−1}, and SLAND_{LAND} was 3.5 ± 0.9 GtC yr−1^{−1}, with a BIM_{IM} of −0.6 GtC yr−1^{−1} (i.e. the total estimated sources were too low or sinks were too high). The global atmospheric CO2_2 concentration averaged over 2021 reached 414.71 ± 0.1 ppm. Preliminary data for 2022 suggest an increase in EFOS_{FOS} relative to 2021 of +1.0 % (0.1 % to 1.9 %) globally and atmospheric CO2_2 concentration reaching 417.2 ppm, more than 50 % above pre-industrial levels (around 278 ppm). Overall, the mean and trend in the components of the global carbon budget are consistently estimated over the period 1959–2021, but discrepancies of up to 1 GtC yr−1^{−1} persist for the representation of annual to semi-decadal variability in CO2_2 fluxes. Comparison of estimates from multiple approaches and observations shows (1) a persistent large uncertainty in the estimate of land-use change emissions, (2) a low agreement between the different methods on the magnitude of the land CO2_2 flux in the northern extratropics, and (3) a discrepancy between the different methods on the strength of the ocean sink over the last decade. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this data set. The data presented in this work are available at https://doi.org/10.18160/GCP-2022 (Friedlingstein et al., 2022b)

    Global carbon budget 2019

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    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere – the “global carbon budget” – is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (EFF) are based on energy statistics and cement production data, while emissions from land use change (ELUC), mainly deforestation, are based on land use and land use change data and bookkeeping models. Atmospheric CO2 concentration is measured directly and its growth rate (GATM) is computed from the annual changes in concentration. The ocean CO2 sink (SOCEAN) and terrestrial CO2 sink (SLAND) are estimated with global process models constrained by observations. The resulting carbon budget imbalance (BIM), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the last decade available (2009–2018), EFF was 9.5±0.5 GtC yr−1, ELUC 1.5±0.7 GtC yr−1, GATM 4.9±0.02 GtC yr−1 (2.3±0.01 ppm yr−1), SOCEAN 2.5±0.6 GtC yr−1, and SLAND 3.2±0.6 GtC yr−1, with a budget imbalance BIM of 0.4 GtC yr−1 indicating overestimated emissions and/or underestimated sinks. For the year 2018 alone, the growth in EFF was about 2.1 % and fossil emissions increased to 10.0±0.5 GtC yr−1, reaching 10 GtC yr−1 for the first time in history, ELUC was 1.5±0.7 GtC yr−1, for total anthropogenic CO2 emissions of 11.5±0.9 GtC yr−1 (42.5±3.3 GtCO2). Also for 2018, GATM was 5.1±0.2 GtC yr−1 (2.4±0.1 ppm yr−1), SOCEAN was 2.6±0.6 GtC yr−1, and SLAND was 3.5±0.7 GtC yr−1, with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 407.38±0.1 ppm averaged over 2018. For 2019, preliminary data for the first 6–10 months indicate a reduced growth in EFF of +0.6 % (range of −0.2 % to 1.5 %) based on national emissions projections for China, the USA, the EU, and India and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. Overall, the mean and trend in the five components of the global carbon budget are consistently estimated over the period 1959–2018, but discrepancies of up to 1 GtC yr−1 persist for the representation of semi-decadal variability in CO2 fluxes. A detailed comparison among individual estimates and the introduction of a broad range of observations shows (1) no consensus in the mean and trend in land use change emissions over the last decade, (2) a persistent low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) an apparent underestimation of the CO2 variability by ocean models outside the tropics. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this data set (Le QuĂ©rĂ© et al., 2018a, b, 2016, 2015a, b, 2014, 2013). The data generated by this work are available at https://doi.org/10.18160/gcp-2019 (Friedlingstein et al., 2019)
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