111 research outputs found
Do carbonate karst terrains affect the global carbon cycle?
Carbonate minerals comprise the largest reservoir of carbon in the earthâs lithosphere, but they are generally assumed to have no net impact on the global carbon cycle if rapid dissolution and precipitation reactions represent equal sources and sinks of atmospheric carbon. Observations of both terrestrial and marine carbonate systems indicate that carbonate minerals may simultaneously dissolve and precipitate within different portions of individual hydrologic systems. In all cases reported here, the dissolution and precipitation reactions are related to primary production, which fixes atmospheric CO2 as organic carbon, and the subsequent remineralization in watersheds of the organic carbon to dissolved CO2. Deposition of carbonate minerals in the ocean represents a flux of CO2 to the atmosphere. The dissolution of oceanic carbonate minerals can act either as a sink for atmospheric CO2 if dissolved by carbonic acid, or as a source of CO2 if dissolved through sulfide oxidation at the freshwater-saltwater boundary. Since dissolution and precipitation of carbonate minerals depend on ecological processes, changes in these processes due to shifts in rainfall patterns, earth surface temperatures, and sea level should also alter the potential magnitudes of sources and sinks for atmospheric CO2 from carbonate terrains, providing feedbacks to the global carbon cycle that differ from modern feedbacks.Keywords: Global carbon cycle, carbonate terrains, organic carbon fixation, remineralization, carbonate mineral dissolution, carbonate mineral precipitation.DOI: 10.3986/ac.v42i2-3.66
E HOÊ»I I KA PIKO - NÄ PIKO Ê»EHÄ - I PIKO HOU NO NÄ PIKO Ê»EKOLU
M.A.M.A. Thesis. University of HawaiÊ»i at MÄnoa 201
A Review of Problem Structuring Methods for Consideration in Prognostics and Smart Manufacturing
Successful use of prognostics involves the prediction of future system behaviors in an effort to maintain system availability and reduce the cost of maintenance and repairs. Recent work by the National Institute of Standards and Technology indicates that the field of prognostics and health management is vital for remaining competitive in todayâs manufacturing environment. While prognostics-based maintenance involves many traditional operations research-centric challenges for successful deployment such as limited availability of information and concerns regarding computational efficiency, the authors argue in this paper that the field of prognostics and health management, still in its embryonic development stage, could benefit greatly from considering soft operations research techniques as well. Specifically, the authors propose the use of qualitative problem structuring techniques that aid in problem understanding and scoping. This paper provides an overview of these soft methods and discusses and demonstrates how manufacturers might use them. An approach combining problem structuring methods with traditional operations research techniques would help accelerate the development of the prognostics field
A Review of Problem Structuring Methods for Consideration in Prognostics and Smart Manufacturing
Successful use of prognostics involves the prediction of future system behaviors in an effort to maintain system availability and reduce the cost of maintenance and repairs. Recent work by the National Institute of Standards and Technology indicates that the field of prognostics and health management is vital for remaining competitive in todayâs manufacturing environment. While prognostics-based maintenance involves many traditional operations researchcentric challenges for successful deployment such as limited availability of information and concerns regarding computational efficiency, the authors argue in this paper that the field of prognostics and health management, still in its embryonic development stage, could benefit greatly from considering soft operations research techniques as well. Specifically, the authors propose the use of qualitative problem structuring techniques that aid in problem understanding and scoping. This paper provides an overview of these soft methods and discusses and demonstrates how manufacturers might use them. An approach combining problem structuring methods with traditional operations research techniques would help accelerate the development of the prognostics field
A Method for Key Performance Indicator Assessment in Manufacturing Organizations
Key Performance Indicators (KPIs) are an essential element of an organizationâs ability to monitor its
strategic health, helping to ensure the strategic goals of the organization are achieved. However, KPI assessment and
improvement is often an ad hoc and consultant-driven process rather than one undertaken using scientific principles.
This paper outlines the development and subsequent deployment of a method for KPI assessment founded in
scholarly literature and balancing practitioner concerns for ease of use. The proposed method draws heavily on
organizational stakeholder involvement at varying levels throughout the KPI assessment process, improving current
methods by introducing a mathematical foundation based on value-focused thinking. The proposed method allows
stakeholders to evaluate the organizationâs KPIs in an effort to determine organizational performance against
predetermined KPI thresholds. The method is demonstrated on a case study and suggestions for future research are
offered
Predicting trajectories of offending over the life course:findings from a Dutch conviction cohort
Criminal Justice: Legitimacy, accountability, and effectivit
The Scientific Investigation of Unidentified Aerial Phenomena (UAP) Using Multimodal Ground-based Observatories
Peer reviewedPublisher PD
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De novo variants in the RNU4-2 snRNA cause a frequent neurodevelopmental syndrome.
Around 60% of individuals with neurodevelopmental disorders (NDD) remain undiagnosed after comprehensive genetic testing, primarily of protein-coding genes1. Large genome-sequenced cohorts are improving our ability to discover new diagnoses in the non-coding genome. Here we identify the non-coding RNA RNU4-2 as a syndromic NDD gene. RNU4-2 encodes the U4 small nuclear RNA (snRNA), which is a critical component of the U4/U6.U5 tri-snRNP complex of the major spliceosome2. We identify an 18âbase pair region of RNU4-2 mapping to two structural elements in the U4/U6 snRNA duplex (the T-loop and stem III) that is severely depleted of variation in the general population, but in which we identify heterozygous variants in 115 individuals with NDD. Most individuals (77.4%) have the same highly recurrent single base insertion (n.64_65insT). In 54 individuals in whom it could be determined, the de novo variants were all on the maternal allele. We demonstrate that RNU4-2 is highly expressed in the developing human brain, in contrast to RNU4-1 and other U4 homologues. Using RNA sequencing, we show how 5 splice-site use is systematically disrupted in individuals with RNU4-2 variants, consistent with the known role of this region during spliceosome activation. Finally, we estimate that variants in this 18âbase pair region explain 0.4% of individuals with NDD. This work underscores the importance of non-coding genes in rare disorders and will provide a diagnosis to thousands of individuals with NDD worldwide
Maria Coswayâs Hours: Cosmopolitan and Classical Visual Culture in Thomas Macklinâs Poets Gallery
Thomas Macklinâs Gallery of Poets opened at the Mitre Tavern in Fleet Street in 1788 with the aim to âdisplay British Geniusâ through âPrints Illustrative of the Most Celebrated British Poetsâ. Early newspaper coverage promised âa monument of the powers of the pencil in England, as the Vatican is at Romeâ. The incongruous juxtaposition between Fleet Street and the Vatican spells out the cosmopolitan ambition of the literary gallery phenomenon through its real and imagined geographies of display. Through the format of the paper gallery of prints, Macklinâs Poets offered the inventions of British Poets as a repository of painting. This chapter examines how the cosmopolitan idiom of the paper gallery is negotiated in the first number of Macklinâs Poets. This essay examines the extent to which this ambition was achieved in the first Number of Macklinâs Poets which carried an engraving of Maria Coswayâs The Hours, originally a painting with an impressively European iconographic heritage. The painting was first exhibited at the Royal Academy in 1783, and was retroactively associated by Macklin with Thomas Grayâs âOde on the Springâ. The trope of the Hours brought with it a weighty provenance derived from classical marble bas-relief, through the antiquarian pages of Pietro Santi Bartoli and Bernard de Montfaucon to Flaxmanâs designs for Wedgwood plaques and vases. Coswayâs name also imported into Grayâs poem her reputation as a cosmopolitan, cultured woman who had completed the Grand Tour and who moved in elite circles including those of the Prince of Wales in London and the Duke of Orleans, Pierre dâHancarville and Thomas Jefferson in Paris. The iconographies of the painting, the print, and the poem articulate a European cosmopolitan tradition for British Art
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