72 research outputs found

    Complete Sets of Reductions Modulo A Class of Equational Theories which Generate Infinite Congruence Classes

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    In this paper we present a generalization of the Knuth-Bendix procedure for generating a complete set of reductions modulo an equational theory. Previous such completion procedures have been restricted to equational theories which generate finite congruence classes. The distinguishing feature of this work is that we are able to generate complete sets of reductions for some equational theories which generate infinite congruence classes. In particular, we are able to handle the class of equational theories which contain the associative, commutative, and identity laws for one or more operators. We first generalize the notion of rewriting modulo an equational theory to include a special form of conditional reduction. We are able to show that this conditional rewriting relation restores the finite termination property which is often lost when rewriting in the presence of infinite congruence classes. We then develop Church-Rosser tests based on the conditional rewriting relation and set forth a completion procedure incorporating these tests. Finally, we describe a computer program which implements the theory and give the results of several experiments using the program

    Termination Via Conditional Reductions

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    We Generalize the Notion of Rewriting Modulo an Equational Theory to Include a Special Form of Conditional Reduction. We Are Able to Show that This Conditional Rewriting Relation Restores the Finite Termination Property Which is Often Lost When Rewriting in the Presence of Infinite Congruence Classes. in Particular, We Are Able to Handle the Class of Collapse Equational Theories Which Contain Associative, Commutative, and Identity Laws for One or More Operators

    Anti-MĂŒllerian Hormone and Lifestyle, Reproductive, and Environmental Factors Among Women in Rural South Africa

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    Few data exist regarding antiMĂŒllerian hormone, a marker of ovarian reserve, in relation to environmental factors with potential ovarian toxicity

    Anti-MĂŒllerian hormone and lifestyle, reproductive, and environmental factors among women in rural South Africa

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    BACKGROUND : Few data exist regarding anti-MĂŒllerian hormone, a marker of ovarian reserve, in relation to environmental factors with potential ovarian toxicity. METHODS : This analysis included 420 women from Limpopo, South Africa studied in 2010-2011. Women were administered comprehensive questionnaires, and plasma concentrations of anti-MĂŒllerian hormone and dichlorodiphenyltrichloroethane were determined. We used separate multivariable models to examine the associations between natural log-transformed anti-MĂŒllerian hormone concentration (ng/ml) and each of the lifestyle, reproductive, and environmental factors of interest, adjusted for age, body mass index, education, and parity. RESULTS : The median age of women was 24 years (interquartile range [IQR] = 22 to 26); the median anti-MĂŒllerian hormone concentration was 3.1 ng/ml (IQR = 2.0 to 6.0). Women who reported indoor residual spraying in homes with painted walls (indicative of exposure to pyrethroids) had 25% lower (95% confidence interval [CI] = -39%, -8%) anti-MĂŒllerian hormone concentrations compared with women who reported no spraying. Little evidence of decreased anti-MĂŒllerian hormone concentrations was observed among women with the highest dichlorodiphenyltrichloroethane levels. Compared with women who used an electric stove, no association was observed among women who cooked indoors over open wood fires. The findings also suggested lower anti-MĂŒllerian hormone concentrations among women who drank coffee (-19% [95% CI = -31%, -5%]) or alcohol (-21% [95% CI = -36%, -3%]). CONCLUSIONS : These are among the first data regarding anti-MĂŒllerian hormone concentrations relative to pesticides and indoor air pollution. Our results are suggestive of decreased ovarian reserve associated with exposure to pyrethroid pesticides, which is consistent with laboratory animal data.http://journals.lww.com/epidem/pages/default.aspx2016-05-31hb201

    Research protocol: general practice organ donation intervention-a feasibility study (GPOD)

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    BACKGROUND: New interventions are required to increase the number of people donating their organs after death. In the United States of America (USA), general practice has proved to be a successful location to increase organ donor registration. However, a dearth of research exists examining this in the United Kingdom (UK). due to the unique challenges presented by the National Health Service (NHS). This protocol outlines a feasibility study to assess whether UK general practice is a feasible and acceptable location for organ donation intervention targeting NHS Organ Donor Register (NHS ODR) membership. METHODS: The primary intervention element, prompted choice, requires general practice to ask patients in consultations if they wish to join the NHS ODR. Two additional intervention techniques will be used to support prompted choice: staff training and leaflets and posters. The intervention will run for 3 months (April-July 2018) followed by a period of data collection. The following methods will be used to assess feasibility, acceptability and fidelity: registration data, a training evaluation survey, focus groups with staff and online surveys for staff and patients. DISCUSSION: By examining the feasibility, acceptability and fidelity of a prompted choice intervention in UK general practice, important knowledge can be gathered on whether it is a suitable location to conduct this. Additional learning can also be gained generally for implementing interventions in general practice. This could contribute to the knowledge base concerning the feasibility of NHS general practice to host interventions

    Oleic Acid Biosynthesis in Plasmodium falciparum: Characterization of the Stearoyl-CoA Desaturase and Investigation as a Potential Therapeutic Target

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    BACKGROUND:Plasmodium falciparum parasitization of erythrocytes causes a substantial increase in the levels of intracellular fatty acids, notably oleic acid. How parasites acquire this monounsaturated fatty acid has remained enigmatic. Here, we report on the biochemical and enzymatic characterization of stearoyl-CoA desaturase (SCD) in P. falciparum. METHODOLOGY/PRINCIPAL FINDINGS:Metabolic labeling experiments allowed us to demonstrate the production of oleic acid from stearic acid both in lysates of parasites incubated with [(14)C]-stearoyl-CoA and in parasite-infected erythrocytes labeled with [(14)C]-stearic acid. Optimal SCD activity was detected in schizonts, the stage of maximal membrane synthesis. This activity correlated with a late trophozoite stage-specific induction of PFE0555w transcripts. PFE0555w harbors a typical SCD signature. Similar to mammalian SCDs, this protein was found to be associated with the endoplasmic reticulum, as determined with PFE0555w-GFP tagged transgenic P. falciparum. Importantly, these parasites exhibited increased rates of stearic to oleic acid conversion, providing additional evidence that PFE0555w encodes the plasmodial SCD (PfSCD). These findings prompted us to assess the activity of sterculic acid analogues, known to be specific Delta9-desaturase inhibitors. Methyl sterculate inhibited the synthesis of oleic acid both with parasite lysates and infected erythrocytes, most likely by targeting PfSCD. This compound exhibited significant, rapid and irreversible antimalarial activity against asexual blood stages. This parasiticidal effect was antagonized by oleic acid. CONCLUSION/SIGNIFICANCE:Our study provides evidence that parasite-mediated fatty acid modification is important for blood-stage survival and provides a new strategy to develop a novel antimalarial therapeutic based on the inhibition of PfSCD

    Perfluoroalkyl substances and lipid concentrations in plasma during pregnancy among women in the Norwegian Mother and Child Cohort Study

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    Perfluoroalkyl substances (PFASs) are widespread and persistent environmental pollutants. Previous studies, primarily among non-pregnant individuals, suggest positive associations between PFAS levels and certain blood lipids. If there is a causal link between PFAS concentrations and elevated lipids during pregnancy, this may suggest a mechanism by which PFAS exposure leads to certain adverse pregnancy outcomes, including preeclampsia

    The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

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    The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

    Evaluation of a novel magneto-optical method for the detection of malaria parasites

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    Improving the efficiency of malaria diagnosis is one of the main goals of current malaria research. We have recently developed a magneto-optical (MO) method which allows high-sensitivity detection of malaria pigment (hemozoin crystals) in blood via the magnetically induced rotational motion of the hemozoin crystals. Here, we evaluate this MO technique for the detection of Plasmodium falciparum in infected erythrocytes using in-vitro parasite cultures covering the entire intraerythrocytic life cycle. Our novel method detected parasite densities as low as approximately 40 parasites per microliter of blood (0.0008% parasitemia) at the ring stage and less than 10 parasites/microL (0.0002% parasitemia) in the case of the later stages. These limits of detection, corresponding to approximately 20 pg/microL of hemozoin produced by the parasites, exceed that of rapid diagnostic tests and compete with the threshold achievable by light microscopic observation of blood smears. The MO diagnosis requires no special training of the operator or specific reagents for parasite detection, except for an inexpensive lysis solution to release intracellular hemozoin. The devices can be designed to a portable format for clinical and in-field tests. Besides testing its diagnostic performance, we also applied the MO technique to investigate the change in hemozoin concentration during parasite maturation. Our preliminary data indicate that this method may offer an efficient tool to determine the amount of hemozoin produced by the different parasite stages in synchronized cultures. Hence, it could eventually be used for testing the susceptibility of parasites to antimalarial drugs

    Comment letters to the National Commission on Commission on Fraudulent Financial Reporting, 1987 (Treadway Commission) Vol. 1

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    https://egrove.olemiss.edu/aicpa_sop/1661/thumbnail.jp
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