71 research outputs found

    GEOCHEMICAL CHARACTERIZATION OF THE BONE SPRING FORMATION, DELAWARE BASIN, USING CHEMOSTRATIGRAPHY AND INTEGRATED PETROPHYSICS

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    The Delaware Basin forms part of West Texas\u27s and New Mexico’s famous petroleum-generating Permian Basin. The Bone Spring Formation is a prolific hydrocarbon producer within this basin, creating one of the world’s richest oil shales. This formation has lithological sequences that are characterized by repeating carbonate and siliciclastic intervals of a third-order cycle which can largely be correlated to highstand and lowstand systems tracts, respectively. Lithological complexity and facies change are manifested by debris flows, turbidites, and slumps. In addition to glacio-eustasy, both tectonism and broader Milankovitch cycles have influenced the depositional history. Previous investigations have utilized cores and wireline logs to provide high-resolution chemo-facies segregation, which can be correlated with reservoir and rock properties; however,core and wireline logs are sporadically collected, whereas drill cuttings are available from most wells. For this study, XRF elemental data derived from drill cuttings collected at 30 – 60ft (9 – 18m) intervals have been compared to wireline well logs. XRF measurements were categorized using hierarchical cluster and principal component analysis based on chemical facies. Chemostratigraphic units and packages were applied to generate cross-sections and facies maps to understand depositional cyclicity, terrigenous influence, grain size, ii mineralogy, organic content and rock property distribution. These data sets can be used to high-grade acreage for resource identification and storage to optimize drilling performance, completion designs and as a geosteering input

    Book Reviews

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    Reviews of the following books: The Lobster Coast: Rebels, Rusticators, and the Struggle for Forgotten Frontier by Colin Woodard; Writing on Stone: Scenes from a Maine Island Life by Christina Marsden Gillis; photographs by Peter Ralston and Forward by Philip Conkling; Owascoag, Black Poynt, Mayne: History of Black Point (Scarborough) Maine, ca. 1600-1800: A Narrative by Patricia Bowden Corey; Continental Liar from the State of Maine: James G. Blaine by Neil Rolde; No Flies on Bill : The Story of an Uncontrollable Old Woman, My Grandmother, Ethel Billie Gammon by Darcy Wakefield; An Upriver Passamaquoddy by Allan J. Sockabasin; Rug Hooking in Maine, 1838 - 1940 by Mildred Cole Peladea

    Cumulative mutagenesis of the basic residues in the 201-218 region of insulin-like growth factor (IGF)-binding protein-5 results in progressive loss of both IGF-I binding and inhibition of IGF-I biological action

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    We have reported previously that mutation of two conserved nonbasic amino acids (G203 and Q209) within the highly basic 201–218 region in the C-terminal domain of IGF-binding protein-5 (IGFBP-5) decreases binding to IGFs. This study reveals that cumulative mutagenesis of the 10 basic residues in this region, to create the C-Term series of mutants, ultimately results in a 15-fold decrease in the affinity for IGF-I and a major loss in heparin binding. We examined the ability of mutants to inhibit IGF-mediated survival of MCF-7 cells and were able to demonstrate that this depended not only upon the affinity for IGF-I, but also the kinetics of this interaction, because IGFBP-5 mutants with similar affinity constants (KD) values, but with different association (Ka) and dissociation (Kd) rate values, had markedly different inhibitory properties. In contrast, the affinity for IGF-I provided no predictive value in terms of the ability of these mutants to enhance IGF action when bound to the substratum. Instead, these C-Term mutants appeared to enhance the actions of IGF-I by a combination of increased dissociation of IGF-IGFBP complexes from the substratum, together with dissociation of IGF-I from IGFBP-5 bound to the substratum. These effects of the IGFBPs were dependent upon binding to IGF-I, because a non-IGF binding mutant (N-Term) was unable to inhibit or enhance the actions of IGF-I. These results emphasize the importance of the kinetics of association/dissociation in determining the enhancing or inhibiting effects of IGFBP-5 and demonstrate the ability to generate an IGFBP-5 mutant with exclusively IGF-enhancing activity

    Human physiologically based pharmacokinetic model for propofol

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    BACKGROUND: Propofol is widely used for both short-term anesthesia and long-term sedation. It has unusual pharmacokinetics because of its high lipid solubility. The standard approach to describing the pharmacokinetics is by a multi-compartmental model. This paper presents the first detailed human physiologically based pharmacokinetic (PBPK) model for propofol. METHODS: PKQuest, a freely distributed software routine , was used for all the calculations. The "standard human" PBPK parameters developed in previous applications is used. It is assumed that the blood and tissue binding is determined by simple partition into the tissue lipid, which is characterized by two previously determined set of parameters: 1) the value of the propofol oil/water partition coefficient; 2) the lipid fraction in the blood and tissues. The model was fit to the individual experimental data of Schnider et. al., Anesthesiology, 1998; 88:1170 in which an initial bolus dose was followed 60 minutes later by a one hour constant infusion. RESULTS: The PBPK model provides a good description of the experimental data over a large range of input dosage, subject age and fat fraction. Only one adjustable parameter (the liver clearance) is required to describe the constant infusion phase for each individual subject. In order to fit the bolus injection phase, for 10 or the 24 subjects it was necessary to assume that a fraction of the bolus dose was sequestered and then slowly released from the lungs (characterized by two additional parameters). The average weighted residual error (WRE) of the PBPK model fit to the both the bolus and infusion phases was 15%; similar to the WRE for just the constant infusion phase obtained by Schnider et. al. using a 6-parameter NONMEM compartmental model. CONCLUSION: A PBPK model using standard human parameters and a simple description of tissue binding provides a good description of human propofol kinetics. The major advantage of a PBPK model is that it can be used to predict the changes in kinetics produced by variations in physiological parameters. As one example, the model simulation of the changes in pharmacokinetics for morbidly obese subjects is discussed

    Using microbiological data to improve the use of antibiotics for respiratory tract infections: A protocol for an individual patient data meta-analysis

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    Background: Resistance to antibiotics is rising and threatens future antibiotic effectiveness. ‘Antibiotic targeting’ ensures patients who may benefit from antibiotics receive them, while being safely withheld from those who may not. Point-of-care tests may assist with antibiotic targeting by allowing primary care clinicians to establish if symptomatic patients have a viral, bacterial, combined, or no infection. However, because organisms can be harmlessly carried, it is important to know if the presence of the virus/bacteria is related to the illness for which the patient is being assessed. One way to do this is to look for associations with more severe/prolonged symptoms and test results. Previous research to answer this question for acute respiratory tract infections has given conflicting results with studies has not having enough participants to provide statistical confidence. Aim: To undertake a synthesis of IPD from both randomised controlled trials (RCTs) and observational cohort studies of respiratory tract infections (RTI) in order to investigate the prognostic value of microbiological data in addition to, or instead of, clinical symptoms and signs. Methods: A systematic search of Cochrane Central Register of Controlled Trials, Ovid Medline and Ovid Embase will be carried out for studies of acute respiratory infection in primary care settings. The outcomes of interest are duration of disease, severity of disease, repeated consultation with new/worsening illness and complications requiring hospitalisation. Authors of eligible studies will be contacted to provide anonymised individual participant data. The data will be harmonised and aggregated. Multilevel regression analysis will be conducted to determine key outcome measures for different potential pathogens and whether these offer any additional information on prognosis beyond clinical symptoms and signs. Trial registration: PROSPERO Registration number: CRD42023376769

    Effect of the relative shift between the electron density and temperature pedestal position on the pedestal stability in JET-ILW and comparison with JET-C

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    The electron temperature and density pedestals tend to vary in their relative radial positions, as observed in DIII-D (Beurskens et al 2011 Phys. Plasmas 18 056120) and ASDEX Upgrade (Dunne et al 2017 Plasma Phys. Control. Fusion 59 14017). This so-called relative shift has an impact on the pedestal magnetohydrodynamic (MHD) stability and hence on the pedestal height (Osborne et al 2015 Nucl. Fusion 55 063018). The present work studies the effect of the relative shift on pedestal stability of JET ITER-like wall (JET-ILW) baseline low triangularity (\u3b4) unseeded plasmas, and similar JET-C discharges. As shown in this paper, the increase of the pedestal relative shift is correlated with the reduction of the normalized pressure gradient, therefore playing a strong role in pedestal stability. Furthermore, JET-ILW tends to have a larger relative shift compared to JET carbon wall (JET-C), suggesting a possible role of the plasma facing materials in affecting the density profile location. Experimental results are then compared with stability analysis performed in terms of the peeling-ballooning model and with pedestal predictive model EUROPED (Saarelma et al 2017 Plasma Phys. Control. Fusion). Stability analysis is consistent with the experimental findings, showing an improvement of the pedestal stability, when the relative shift is reduced. This has been ascribed mainly to the increase of the edge bootstrap current, and to minor effects related to the increase of the pedestal pressure gradient and narrowing of the pedestal pressure width. Pedestal predictive model EUROPED shows a qualitative agreement with experiment, especially for low values of the relative shift

    What might the Covid Pandemic mean for the SERA Theory and Philosophy of Education Network?

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    Some prominent theorists and philosophers of education recently offered their reflections on the ongoing crisis by way of a collective project which begins with the provocative words of Arundhati Roy: “[o]ur minds are still racing back and forth, longing for a return to ‘normality’”
“[n]othing could be worse that a return to normality” (Peters et. al. 2020, 1). Whether or not one is persuaded, Roy is surely right that this rupture offers us a glimpse of something different if we are “ready to imagine another world” (Roy 2020). Roy points to the “brutal, structural, social and economic inequality” of India and elsewhere that the pandemic has illuminated. That it takes a pandemic to face some basic social problems may be disheartening, but it suggests that, in an era of such fundamental uncertainty, we may be able to meaningfully open up basic questions of the nature and purpose of education, questions that are otherwise taken for granted. Thus, the theoretical and philosophical basis of our educational work comes into sharper focus

    Editorial

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    Editorial for Theory & Philosophy Network Special Issue no 11

    Beyond virtue and vice : a return to uncertainty

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    Education is astonishingly simple. We have all been through it, whether as children or later in life – indeed, many of us are still going through it in some form or other; we all know what works; and we are all committed to realising its individual and social potential. Such a view of the matter might dispense with the need for philosophy of education altogether since the problems of education are seen as little more than puzzles to be solved. We know (or think that we know) what we want to achieve, the challenge is how to do so most efficiently. If only the virtues of education were this perspicuous, this simple. If only the vices were so easily identified and expunged. It turns out that education is astonishingly complex. The following chapters aspire to re-introduce a certain complexity that abstains from an all-too easy understanding. They seek not to offer solutions, but complications, disruptions, dissensions. The authors assume positions against the usual associations and evaluations regarding certain words and phrases – a revaluation that turns the virtues to vices and the vices to virtues
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