39 research outputs found

    Examining Rational Bubbles in Oil Prices: Evidence from Frequency Domain Estimates

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    This study examined the existence of rational bubbles in oil prices by employing a frequency domain econophysics technique that have capacity to identify both explosive behaviour and bubbles in oil prices for the three largest oil future markets – WTI, Brent and OPEC basket. Our results show that the three prices experienced bubbles in four distinct periods. We attempt to provide some explanations on each of these bubbles using geopolitical, war and economic events. We equally noted that oil prices bubbles are largely influenced by the fact that oil is a major source of energy and is nonrenewable. The study observed that existence of bubbles have some economic consequences such as welfare loss resulting from distortion in prices and economic instability among others. We provide some policy recommendatio

    Activity-Based Funding of Hospitals and Its Impact on Mortality, Readmission, Discharge Destination, Severity of Illness, and Volume of Care: A Systematic Review and Meta-Analysis

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    Background: Activity-based funding (ABF) of hospitals is a policy intervention intended to re-shape incentives across health systems through the use of diagnosis-related groups. Many countries are adopting or actively promoting ABF. We assessed the effect of ABF on key measures potentially affecting patients and health care systems: mortality (acute and post-acute care); readmission rates; discharge rate to post-acute care following hospitalization; severity of illness; volume of care.     Methods: We undertook a systematic review and meta-analysis of the worldwide evidence produced since 1980. We included all studies reporting original quantitative data comparing the impact of ABF versus alternative funding systems in acute care settings, regardless of language. We searched 9 electronic databases (OVID MEDLINE, EMBASE, OVID Healthstar, CINAHL, Cochrane CENTRAL, Health Technology Assessment, NHS Economic Evaluation Database, Cochrane Database of Systematic Reviews, and Business Source), hand-searched reference lists, and consulted with experts. Paired reviewers independently screened for eligibility, abstracted data, and assessed study credibility according to a pre-defined scoring system, resolving conflicts by discussion or adjudication.     Results: Of 16,565 unique citations, 50 US studies and 15 studies from 9 other countries proved eligible (i.e. Australia, Austria, England, Germany, Israel, Italy, Scotland, Sweden, Switzerland). We found consistent and robust differences between ABF and no-ABF in discharge to post-acute care, showing a 24% increase with ABF (pooled relative risk = 1.24, 95% CI 1.18–1.31). Results also suggested a possible increase in readmission with ABF, and an apparent increase in severity of illness, perhaps reflecting differences in diagnostic coding. Although we found no consistent, systematic differences in mortality rates and volume of care, results varied widely across studies, some suggesting appreciable benefits from ABF, and others suggesting deleterious consequences.     Conclusions: Transitioning to ABF is associated with important policy- and clinically-relevant changes. Evidence suggests substantial increases in admissions to post-acute care following hospitalization, with implications for system capacity and equitable access to care. High variability in results of other outcomes leaves the impact in particular settings uncertain, and may not allow a jurisdiction to predict if ABF would be harmless. Decision-makers considering ABF should plan for likely increases in post-acute care admissions, and be aware of the large uncertainty around impacts on other critical outcomes

    Treated Rhizophora mucronata tannin as a corrosion inhibitor in chloride solution

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    Treated Rhizopora mucronata tannin (RMT) as a corrosion inhibitor for carbon steel and copper in oil and gas facilities was investigated. Corrosion rate of carbon-steel and copper in 3wt% NaCl solution by RMT was studied using chemical (weight loss method) and spectroscopic (FTIR) techniques at various temperatures in the ranges of 26–90C. The weight loss data was compared to the electrochemical by the application of Faraday’s law for the conversion of corrosion rate data from one system to another. The inhibitive efficiency of RMT was compared with commercial inhibitor sodium benzotriazole (BTA-S). The best concentration of RMT was 20% (w/v), increase in concentration of RMT decreased the corrosion rate and increased the inhibitive efficiency. Increase in temperature increased the corrosion rate and decreased the inhibitive efficiency but, the rate of corrosion was mild with RMT. The FTIR result shows the presence of hydroxyl group, aromatic group, esters and the substituted benzene group indicating the purity of the tannin. The trend of RMT was similar to that of BTA-S, but its inhibitive efficiency for carbon-steel was poor (6%) compared to RMT (59%). BTA-S was efficient for copper (76%) compared to RMT (74%) at 40% (w/v) and 20% (w/v) concentration respectively. RMT was efficient even at low concentration therefore, the use of RMT as a cost effective and environmentally friendly corrosion inhibiting agent for carbon steel and copper is herein proposed

    Non-invasive determination of reference arterial blood pressure indices of healthy Alsatian and Boerboel dogs

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    In order to evaluate and manage Boerboels and Alsatians under critical and emergency care, knowledge of ranges and causes of variability of normal arterial blood pressure (ABP) indices is desirable. The systolic arterial pressure (SAP), diastolic arterial pressure (DAP) and mean arterial pressure (MAP) of 30 healthy dogs were evaluated with human sphygmomanometer and neonatal cuff. The age, sex, breed, weight, height, weight to height ratio (WTH), of each dog was recorded. The mean and range of ABP values for Alsatians and Boerboels were similar to those of some other breeds. There were no age, breed and sex differences in ABP indices of dogs. The coefficient of variations and ranges of DAP and MAP were significantly higher than SAP measurements. In all dogs, SAP was influenced by breed and interaction of breed and sex when all confounders were controlled. The WTH and sex were found to independently influence SAP in presence of confounders. In Alsatian, WTH and sex interaction influenced all pressures in presence of confounders. The DAP was significantly influenced by heart rate and WTH in presence and absence of confounders respectively. Although age did not influence ABP in all dogs, it influenced SAP and DAP in females and Boerboel. The absence of age, sex, and breed differences in ABP of dogs may be due to multiple interactions between these factors. The human sphygmomanometer has the best precision for SAP measurements and WTH may be used as canine’s body mass index (BMI) because of its influence on ABP.Keywords: Blood pressure, dogs, breed, sex, age, oscillometr

    qSUB2: A novel QTL with positive epistasis with SUB1 locus enhances submergence tolerance in rice

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    Climate change is expected to significantly increase submergence stress of lowland rice (Oryza sativa) production in Africa. There is a need to further improve the ability of SUB1 gene to tolerate submergence stress. Genetic control of submergence tolerance was studied in a moderately tolerant to submergence African rice landrace “TOS6454.” Three mapping populations with a total of 1182 lines were developed by crossing TOS6454 with three popular rice varieties of West Africa that are high-yielding but submergence susceptible, that is, FARO44, FARO52, and FARO60. The screening for submergence was conducted at the Africa Rice Center (AfricaRice) station in Ibadan, Nigeria during 2016–2018. The three mapping populations were genotyped with single nucleotide polymorphic markers either on the Kompetitive allele specific PCR or the DArTseq platforms. Quantitative trait locus (QTL) analysis revealed five different QTLs on chromosomes 1, 2, 3, 4, and 9. The QTLs on chromosomes 2 (qSUB2) and 9 (qSUB9) had consistent large effects and the tolerance alleles were contributed by TOS6454. The QTL on chromosome 9 (qSUB9) had a large effect on submergence tolerance in all three mapping populations. This QTL had a highest logarithm of odds (LOD) score of 30.46 and explained as much as 27.7% phenotypic variation (R2), with an additive effect of up to 9.39. The QTL on chromosome 2 (qSUB2) had a highest LOD score of 10.78 and explained up to 10.8% R2 for this trait. Furthermore, qSUB2 had positive epistasis with qSUB9 which further increased submergence tolerance. A total of 57 lines carrying both qSUB2 and qSUB9 alleles were superior to all other lines in submergence tolerance. qSUB9 co-segregated with ART5 a marker for the SUB1 gene; thus, it is suggested that qSUB9 is the same as the well-known SUB1 gene. Pyramiding qSUB2 with the SUB1 gene locus is expected to further improve submergence tolerance in elite rice varieties

    An overview of chemical enhanced oil recovery: recent advances and prospects

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    Despite the progress made on renewable energy, oil and gas remains the world’s primary energy source. Meanwhile, large amounts of oil deposits remain unrecovered after application of traditional oil recovery methods. Chemical enhanced oil recovery (EOR) has been adjudged as an efficient oil recovery technique to recover bypassed oil and residual oil trapped in the reservoir. This EOR method relies on the injection of chemicals to boost oil recovery. In this overview, an up-to-date synopsis of chemical EOR with detailed explanation of the chemicals used, and the mechanism governing their oil recovery application have been discussed. Challenges encountered in the application of the various conventional chemical EOR methods were highlighted, and solutions to overcome the challenges were proffered. Besides, the recent trend of incorporating nanotechnology and their synergistic effects on conventional chemicals stability and efficiency for EOR were also explored and analysed. Finally, laboratory results and field projects were outlined. The review of experimental studies shows that pore-scale mechanisms of conventional chemical EOR is enhanced by incorporating nanotechnology, hence, resulted in higher efficiency. Moreover, the use of ionic liquid chemicals and novel alkaline–cosolvent–polymer technology shows good potentials. This overview presents an extensive information about chemical EOR applications for sustainable energy production

    Application of Polymers for Chemical Enhanced Oil Recovery: A Review

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    Polymers play a significant role in enhanced oil recovery (EOR) due to their viscoelastic properties and macromolecular structure. Herein, the mechanisms of the application of polymeric materials for enhanced oil recovery are elucidated. Subsequently, the polymer types used for EOR, namely synthetic polymers and natural polymers (biopolymers), and their properties are discussed. Moreover, the numerous applications for EOR such as polymer flooding, polymer foam flooding, alkali–polymer flooding, surfactant–polymer flooding, alkali–surfactant–polymer flooding, and polymeric nanofluid flooding are appraised and evaluated. Most of the polymers exhibit pseudoplastic behavior in the presence of shear forces. The biopolymers exhibit better salt tolerance and thermal stability but are susceptible to plugging and biodegradation. As for associative synthetic polyacrylamide, several complexities are involved in unlocking its full potential. Hence, hydrolyzed polyacrylamide remains the most coveted polymer for field application of polymer floods. Finally, alkali–surfactant–polymer flooding shows good efficiency at pilot and field scales, while a recently devised polymeric nanofluid shows good potential for field application of polymer flooding for EOR
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