338 research outputs found

    The composition of famuli labour on English demesnes, c.1300

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    This article explores the nature of agricultural labour in England c.1300. Using a national sample of over 400 manorial accounts containing detailed data for over 4000 individuals, the piece looks closely at famuli labour, the nucleus of the workforce on seigneurial demesnes (the farms directly cultivated by manorial lords as opposed to the land of their tenants) at the beginning of the fourteenth century, a period considered to be the pinnacle of medieval population and intensive land exploitation. By examining the rates of remuneration as well as the availability of work for the range of famuli labourers, we argue that famuli labour was divided into a bipartite system of first- and second-tier workers where core, or first-tier (and mostly male), labourers such as ploughmen, carters, and shepherds were paid higher wages and presented with more opportunities to work as compared to a group of more subsidiary 'second-tier' labourers largely comprised of women, the young and the elderly

    Analysis of the conversion of Ī“-(l-Ī±-aminoadipoyl)-l-cysteinyl-d-Ī±-aminobutyrate by active-site mutants of Aspergillus nidulans isopenicillin N synthase

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    AbstractBackground: Penicillins and cephalosporins constitute a major class of clinically useful antibiotics. A key step in their biosynthesis involves the oxidative cyclisation of Ī“-l-Ī±-aminoadipoyl)-l-cysteinyl-d-valine to isopenicillin N by isopenicillin N synthase (IPNS). This chemically remarkable transformation has been extensively studied using substrate analogues. The conversion of an analogue in which the valine is replaced by a-aminobutyrate results in three products, two epimeric penams and a cepham. The ratio of these products in reactions catalysed by four different IPNS isozymes has been used previously to probe the thermicity of the chemical mechanism. But how IPNS restricts the products from the natural substrate to a single penam (isopenicillin N) has remained unknown.Results: A key active-site residue, Leu223, identified according to a model of enzyme-substrate binding, has been altered to sterically less demanding residues. As the steric constraints on the upper part of the active site are reduced, the ratio of the Ī²-methyl penam to the cepham increases when the Ī±-aminobutyrate-containing substrate analogue is used. These results suggest a mechanism for processing of the natural substrate in which IPNS uses steric control to restrict the conformational freedom of an intermediate such that the only product is the penam.Conclusions: Using steric pressure to control conformation, and hence to disfavour reactions leading to alternate products, is probably the result of evolutionary selection for a biologically active product at the expense of biologically inactive byproducts. It is likely that this sort of enzymatic catalysis is used in situations where substrate conversion is highly exothermic and a variety of products are possible

    Final Report on Retrospective Testing and Application of an Automated Building Commissioning Analysis Tool (ABCAT)

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    More than $18 billion of energy is wasted annually in the U.S. commercial building sector. Commissioning services have proven successful in reducing building energy consumption, but the optimal energy performance obtained by commissioning may subsequently degrade. Therefore, it is very helpful to have tools that can help maintain the optimal building energy performance. An Automated Building Commissioning Analysis Tool (ABCAT) that combines a calibrated simulation operated in conjunction with diagnostic techniques is such a simple and cost efficient tool, which can continuously monitor whole building energy consumption after commissioning, warn operation personnel when an HVAC system problem has increased energy consumption, and assist them in identifying the possible cause(s) of the problem. This report presents the results of six retrospective and nine live test case implementations of ABCAT on a total of fifteen buildings located in the United States and Europe. For each building, the energy simulation model used was calibrated to the building energy consumption data in a baseline period. Then, the model was used to predict the optimal cooling and heating consumption in the following days. A cumulative energy difference plot is the primary fault detection metric used in ABCAT; this plot continuously computes and plots the algebraic sum of the daily differences between the measured and simulated consumption. A fault detection standard is developed and defined in the report. In total, ABCAT detected 23 faults in ten of the fifteen buildings using the fault detection standard developed and other means. This report also outlines a methodology for identifying the cause(s) of the faults identified. Where applicable, the reasons for the detected faults are discussed in the report. The causes of some of the detected faults are verified with historical documentation, and the remaining diagnoses remain unconfirmed due to data quality issues, incomplete information on maintenance performed in the buildings and time constraints

    Recreational ketamine-related deaths notified to the National Programme on Substance Abuse Deaths, England, 1997-2019

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    Ā© 2021 The Authors. This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/open-access-at-sage).Background: Ketamine is a phencyclidine derivative with dissociative anaesthetic properties. Increasing numbers of individuals in England take ketamine recreationally. Information on deaths arising from such use in England is presented. Methods: Cases were extracted on 31 January 2020 from the National Programme on Substance Abuse Deaths database, based on text searches of the cause of death, coronerā€™s verdict and positive toxicology results for the terms ā€˜ketamineā€™ or ā€˜norketamineā€™. Findings: During 1997ā€“2005, there were <5 deaths p.a. in which ketamine was implicated. Numbers increased until 2009 (21), plateauing until 2016; thereafter, deaths have risen to about 30 p.a. Decedentsā€™ characteristics (N = 283): male 84.1%, mean age 31.2 (SD 10.0) years, employed 56.5%, drug use history 79.6% and living with others 60.3%. Ketamine was detected with other substances in most cases. Main (74.6%) underlying cause of death was accidental poisoning. Ketamine may have impaired judgement in other cases. Conclusions: Although controlled, recreational ketamine use and related fatalities continue to increase. Consumers need to be more aware of the potentially fatal risks they face.Peer reviewedFinal Published versio

    Symmetric Grothendieck polynomials, skew Cauchy identities, and dual filtered Young graphs

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    Symmetric Grothendieck polynomials are analogues of Schur polynomials in the K-theory of Grassmannians. We build dual families of symmetric Grothendieck polynomials using Schur operators. With this approach we prove skew Cauchy identity and then derive various applications: skew Pieri rules, dual filtrations of Young's lattice, generating series and enumerative identities. We also give a new explanation of the finite expansion property for products of Grothendieck polynomials

    Tilt engineering of spontaneous polarization and magnetization above 300 K in a bulk layered perovskite

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    Crystalline materials that combine electrical polarization and magnetization could be advantageous in applications such as information storage, but these properties are usually considered to have incompatible chemical bonding and electronic requirements. Recent theoretical work on perovskite materials suggested a route for combining both properties. We used crystal chemistry to engineer specific atomic displacements in a layered perovskite, (CaySr1ā€“y)1.15Tb1.85Fe2O7, that change its symmetry and simultaneously generate electrical polarization and magnetization above room temperature. The two resulting properties are magnetoelectrically coupled as they arise from the same displacements

    Anterior Abdominal Stab Injury: A Comparison of Self-Inflicted and Intentional Third-Party Stabbings

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    Background: There is minimal literature comparing self-inflicted (SI) with nonā€“self-inflicted (NSI) anterior abdominal stab wounds (AASW). Methods: Adult patients treated at a level 1 trauma center from 2006 through 2011 with an AASW were reviewed. Results: There were 215 patients with an AASW; 20% were SI. NSI patients had more nonabdominal injuries (47% vs 16%, P \u3c .01) and disposition directly to the operating room (45% vs 26%, P = .02). Intra-abdominal injury rates were similar. One hundred twenty-eight patients had isolated AASWs; 28% were SI. SI patients had higher admission rates (86% vs 63%, P = .01). One hundred three patients had isolated stable/asymptomatic AASWs; 31% were SI. SI patients had more admissions (84% vs 52%, P \u3c .01), had higher intensive care unit admission rates (23% vs 5%, P = .01), longer LOS (3.2 vs 1.4, P \u3c .01), and higher hospital charges (18,000vs18,000 vs 11,000, P \u3c .01). The rates of intra-abdominal injury were again similar. Conclusions: Controlling for extra-abdominal injuries, SI AASW patients have similar rates of intra-abdominal injury but use more resources

    Anterior Abdominal Stab Injury: A Comparison of Self-Inflicted and Intentional Third-Party Stabbings

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    Background: There is minimal literature comparing self-inflicted (SI) with nonā€“self-inflicted (NSI) anterior abdominal stab wounds (AASW). Methods: Adult patients treated at a level 1 trauma center from 2006 through 2011 with an AASW were reviewed. Results: There were 215 patients with an AASW; 20% were SI. NSI patients had more nonabdominal injuries (47% vs 16%, P \u3c .01) and disposition directly to the operating room (45% vs 26%, P = .02). Intra-abdominal injury rates were similar. One hundred twenty-eight patients had isolated AASWs; 28% were SI. SI patients had higher admission rates (86% vs 63%, P = .01). One hundred three patients had isolated stable/asymptomatic AASWs; 31% were SI. SI patients had more admissions (84% vs 52%, P \u3c .01), had higher intensive care unit admission rates (23% vs 5%, P = .01), longer LOS (3.2 vs 1.4, P \u3c .01), and higher hospital charges (18,000vs18,000 vs 11,000, P \u3c .01). The rates of intra-abdominal injury were again similar. Conclusions: Controlling for extra-abdominal injuries, SI AASW patients have similar rates of intra-abdominal injury but use more resources

    Visible Light Photo-oxidation of Model Pollutants Using CaCu3Ti4O12: An Experimental and Theoretical Study of Optical Properties, Electronic Structure, and Selectivity

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    [Image: see text] Charge transfer between metal ions occupying distinct crystallographic sublattices in an ordered material is a strategy to confer visible light absorption on complex oxides to generate potentially catalytically active electron and hole charge carriers. CaCu(3)Ti(4)O(12) has distinct octahedral Ti(4+) and square planar Cu(2+) sites and is thus a candidate material for this approach. The solāˆ’gel synthesis of high surface area CaCu(3)Ti(4)O(12) and investigation of its optical absorption and photocatalytic reactivity with model pollutants are reported. Two gaps of 2.21 and 1.39 eV are observed in the visible region. These absorptions are explained by LSDA+U electronic structure calculations, including electron correlation on the Cu sites, as arising from transitions from a Cu-hybridized O 2p-derived valence band to localized empty states on Cu (attributed to the isolation of CuO(4) units within the structure of CaCu(3)Ti(4)O(12)) and to a Ti-based conduction band. The resulting charge carriers produce selective visible light photodegradation of 4-chlorophenol (monitored by mass spectrometry) by Pt-loaded CaCu(3)Ti(4)O(12) which is attributed to the chemical nature of the photogenerated charge carriers and has a quantum yield comparable with commercial visible light photocatalysts
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