3,805 research outputs found

    Electrical continuity scanner facilitates identification of wires for soldering to connectors

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    Electrical continuity scanner automatically scans 50 wires in 2 seconds to correlate all wires in a circuit with their respective known ends. Modifications made to the basic plan provide circuitry for scanning up to 250 wires

    Changes in invertebrate assemblage composition in benthic and hyporheic zones during a severe supraseasonal drought

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    Droughts are unpredictable disturbances characterized in streams by declining flow, reduced habitat availability, and deteriorating abiotic conditions. Such events typically reduce benthic invertebrate taxon richness and modify assemblage composition, but little is known about how hyporheic invertebrate assemblages respond to drought or how these responses relate to changes in benthic assemblages. We hypothesized that taxon richness (diversity) and variability (as within-site diversity) in benthic assemblage composition would decline as drought proceeded, whereas concurrent changes in hyporheic assemblages would be lower in this more stable environment. We predicted that benthic assemblage composition between sites would converge as epigean taxa were selectively eliminated, whereas between-site hyporheic diversity would change little. We sampled benthic and hyporheic invertebrates concurrently from 4 sites along a groundwater-fed stream during the final stages of a severe supraseasonal drought punctuated by a record heat wave. Abiotic conditions in benthic habitats deteriorated as flow declined, but changes were less pronounced in the hyporheic zone. Benthic diversity declined during drought, whereas hyporheic diversity changed little. However, benthic within-site diversity increased as the drought progressed because of localized variation in the abundance of common taxa. Temporal trends in hyporheic diversity were less consistent. Benthic assemblages at individual sites became more similar, especially during the heat wave, reflecting low diversity and abundance. Hyporheic assemblages changed markedly because of temporary increases in abundances of epigean and hypogean amphipods. These contrasting responses of benthic and hyporheic assemblages to drought should be recognized when developing management strategies for drought-impacted streams

    The relationships between total acidity, titratable acidity and pH in grape tissue

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    The relationships between the total acidity, titratable acidity and pH in grape cluster tissue have been proposed and confirmed. Published data for seven cultivars, eight vineyard locations and eight seasons have been used to demonstrate the general nature of these relationships. A mechanism for the uptake of monovalent metal cations is proposed and its effect on the acidity measures in grapes is shown.Les rapports entre l'acidité total, l'acidité titrable et le pH dans le tissu de raisinLes rapports fondamentaux permettant une prédiction de l'acidité titrable et du pH du tissu et du jus de raisin ont été étudiés. L'influence de quelques substances minérales, en particulier du potassium, sur l'acidité titrable et sur le pH est exposée. Un mécanisme possible de transport dans les baies est discuté. Les relations existantes sont vérifiées à l'aide des analyses déjà publiées réalisées sur baies des cépa­ges Merlot et Cabernet Sauvignon. Des analyses de la pulpe, des pellicules et des rafles des cépages Semillon, Sauvignon blanc, Merlot et Cabernet Sauvignon confirment les rapports discutés. Les valeurs de l'acidité titrable et du pH trouvées pour les jus des cé­pages Riesling, Crouchen et Syrah sont comparées avec les chiffres déjà publiés pour démontrer Je caractère universel des relations existantes

    Spotlight on the Replisome: Aetiology of DNA Replication-Associated Genetic Diseases.

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    Human development and tissue homeostasis depend on the regulated control of cellular proliferation and differentiation. DNA replication is essential to couple genome duplication and cell division with the establishment and maintenance of cellular differentiation programs. In eukaryotes, DNA replication is performed by a large machine known as the 'replisome,' which is strictly regulated in a cell cycle-dependent manner. Inherited mutations of replisome components have been identified in a range of genetic conditions characterised by developmental abnormalities and reduced organismal growth in addition to an involvement of the immune and endocrine systems and/or heightened tumour predisposition. Here, we review the current knowledge of the molecular genetics of replisome dysfunction disorders and discuss recent mechanistic insights into their pathogenesis, with a focus on the specific steps of DNA replication affected in these human diseases

    The decline of adult smallpox in eighteenth-century London.

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    Smallpox was probably the single most lethal disease in eighteenth-century Britain, but was a minor cause of death by the mid-nineteenth century. Although vaccination was crucial to the decline of smallpox, especially in urban areas, from the beginning of the nineteenth century, it remains disputed the extent to which smallpox mortality declined before vaccination. Analysis of age-specific changes in smallpox burials within the large west London parish of St Martin-in-the-Fields revealed a precipitous reduction in adult smallpox risk from the 1770s, and this pattern was duplicated in the east London parish of St Dunstan's. Most adult smallpox victims were rural migrants, and such a drop in their susceptibility is consistent with a sudden increase in exposure to smallpox in rural areas. We investigated whether this was due to the spread of inoculation, or an increase in smallpox transmission, using changes in the age patterns of child smallpox burials. Smallpox mortality rose among infants, and smallpox burials became concentrated at the youngest ages, suggesting a sudden increase in infectiousness of the smallpox virus. Such a change intensified the process of smallpox endemicization in the English population, but also made cities substantially safer for young adult migrants.We would like to thank the Wellcome Trust, Award no. 081508, for funding the research on St Martin-in-the-Fields ... Romola Davenport was partially funded by a Wellcome strategic award, ‘Generation to Reproduction’

    System Description: an Interface Between CLAM and HOL

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    . The CLaM proof planner has been interfaced to the HOL interactive theorem prover to provide the power of proof planning to people using HOL for formal verification, etc. The interface sends HOL goals to CLaM for planning and translates plans back into HOL tactics that solve the initial goals. The project homepage can be found at http://www.cl.cam.ac.uk/Research/HVG/Clam.HOL/intro.html. 1 Introduction CLaM [2] is a proof planning system for Oyster, a tactic-based implementation of the constructive type theory of Martin-Lof. CLaM works by using formalized pre- and post-conditions of Oyster tactics as the basis of plan search. These specifications of tactics are called methods. When a plan for a goal is found, the expectation is that the resulting tactic will solve the goal. Experience shows that the search space for plans is often tractable: CLaM has been able to automatically plan many proofs. A particular emphasis of research with CLaM has been the automation of inductive proo..

    System Description: CyNTHIA

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    A General Framework for Sound and Complete Floyd-Hoare Logics

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    This paper presents an abstraction of Hoare logic to traced symmetric monoidal categories, a very general framework for the theory of systems. Our abstraction is based on a traced monoidal functor from an arbitrary traced monoidal category into the category of pre-orders and monotone relations. We give several examples of how our theory generalises usual Hoare logics (partial correctness of while programs, partial correctness of pointer programs), and provide some case studies on how it can be used to develop new Hoare logics (run-time analysis of while programs and stream circuits).Comment: 27 page
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