421 research outputs found

    Oil price forecasting using gene expression programming and artificial neural networks

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    This study aims to forecast oil prices using evolutionary techniques such as gene expression programming (GEP) and artificial neural network (NN) models to predict oil prices over the period from January 2, 1986 to June 12, 2012. Autoregressive integrated moving average (ARIMA) models are employed to benchmark evolutionary models. The results reveal that the GEP technique outperforms traditional statistical techniques in predicting oil prices. Further, the GEP model outperforms the NN and the ARIMA models in terms of the mean squared error, the root mean squared error and the mean absolute error. Finally, the GEP model also has the highest explanatory power as measured by the R-squared statistic. The results of this study have important implications for both theory and practice

    The exposure of shipping firms’ stock returns to financial risks and oil prices: a global perspective

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    Shipping is an industry that is highly geared towards international trade and therefore, would seem to be highly susceptible to fluctuations in macroeconomic factors. This article investigates the impact of exchange rates, interest rates and oil prices on stock returns of 143 shipping companies from 16 countries. We also investigate the factors which determine the extent to which firm are sensitive to macroeconomic variables. Our results indicate that the low incidence of significant exposure to exchange rate and interest rates suggests that most shipping firms have utilised reasonably successful hedging strategies to reduce the impact of these macroeconomic risks. Finally, we find that, for the minority of shipping firms significantly affected by oil price increases, the effects have usually been beneficial

    The Electron Microscope Detection and X-Ray Quantitation of Cations in Bacterial Cells

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    Electron microscope autoradiography and X-ray microanalysis have been used for the detection and quantitation of cations in the bacterium Pseudomonas tabaci. These techniques differ in the information they provide (relating to either cation uptake or in situ levels), their applicability to different cations, their sensitivity and their spatial resolution. With uptake of 63Ni2+, high resolution autoradiography (involving gold latensification and physical development) demonstrated a high degree of cation localisation to the central nucleoid area (glutaraldehyde-fixed cells) and within this to the constituent chromatin (acetic-alcohol preparations). X-ray microanalysis of whole bacterial cells revealed the presence of substantial levels of K (mainly soluble cation}, Ca, Mn, Ni, Cu and Zn (mainly in soluble cations) and Fe (present as major soluble and insoluble components). The use of whole cells provided a particularly useful experimental system to demonstrate the importance of cell preparation technique in relation to element detectability. The application of X-ray microanalysis to lysed cells permitted analysis of extruded contents -including cell protoplast (protoplasm without associated cell wall material) and chromatin fibrils. The microprobe detection of DNA-associated cations was most effective with freshly extracted chromatin and showed the presence of bound K, Ca and transition metals

    EFFICIENCY OF TWO MOLECULAR TOOLS BASED ON DNA USED FOR DIFFERENTIATING SOME MICROBIAL STRAINS

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    In the present study, two molecular biology tools based on DNA were compared in the differentiating between some microbial strains isolated from soil. Two types (16SrRNA and 18SrRNA) of ribosomal RNA genes were used for identification of the four bacterial and three fungal isolates, respectively. The identified microbial isolates were submitted in GenBank as strains of Escherichia coli MSL-19 (LC455952.1); Bacillus sp. MSLB-1 (LC455953.1); Bacillus sp. MSLB2 (LC455954.1); Bacillus sp. MSLB3 (LC455955.1); Penicillium sp. MLSP1 (LC455956.1); Aspergillus niger MLSAs1 (LC455958.1); Aspergillus sp. MLSAs2 (LC455959.1). The DNA obtained from the seven microbial strains was used as templates for RAPDPCR differentiating in the presence of eight random primers. Electrophoresis analysis was performed, and on scoring, the identity percentages between the bacterial and fungal strains were separately analyzed. A percentage of 82-83% was recorded between the E. coli and the three Bacillus strains, while, identities of 93-98% were recorded between the three Bacillus strains. Similar trend (90-96%) was observed between the Penicillium and Aspergillus strains. Results confirmed that identities based on the two ribosomal RNA genes (82-98%) was higher than that of RAPD-PCR (70.0-79.7%), and this is because of ribosomal RNA genes are in limited sizes (~1500-1600 bp) and specific for differentiating species, while RAPD-PCR tool depends on using some random primers could be recorded on the whole genome. The phylogenetic trees based on the two molecular  tools supported the obtained results. As a conclusion, tools of RAPD-PCR and ribosomal RNA genes were successfully used to identify and detect the genetic variability of microbial strains isolated from soil

    Comparison of the accuracy of two scoring systems in predicting the outcome of organophosphate intoxicated patients admitted to intensive care unit (ICU)

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    AbstractIntroductionOrganophosphates(OP) are one of the most common causes of poisoning, especially in developing countries, with high morbidity and mortality. As mortality rate of OP poisoning is still high, early diagnosis and appropriate treatment is often life saving. OP is the main cause of poisoning and death in the poison control centre (PCC), Ain Shams University (ASU) in Egypt.ObjectiveTo compare the accuracy of acute physiology and chronic health evaluation score (APACHE IV) and simplified acute physiology score (SAPS II) in the prediction of mortality of patients with organophosphate poisoning (OPP) who required admission to the Intensive Care Unit (ICU) of PCC of ASU between January 1st, 2009 and December 31st, 2009.MethodsA prospective study conducted by collecting data on consecutive patients with acute OPP admitted to the intensive care unit over 12months. Data required to calculate the patients’ predicted mortality by (APACHE) IV and (SAPS) II scoring systems were collected.ResultsNinety patients were recruited in the study with acute OP toxicity. The observed mortality following acute OP toxicity was 13.3% (12 patients). The area under the receiver operator characteristic (ROC) curves of APACHE IV score was better than SAPS II score (0.921±0.054 SE, 0.807±0.078 SE, respectively). APACHE IV and SAPS II scores were significantly higher in the non-survival than in the survival group (P<0.05).ConclusionAPACHE IV and SAPS II scores calculated within the first 24h are good prognostic indicators among patients with acute OP toxicity that required ICU admission with preference to APACHE IV score. APACHE IV and SAPS II scores above 89, 44, respectively within the first 24h are a predictor of poor outcome in patients with acute OP toxicity.RecommendationApplication of APACHE IV and SAPS II scores is a good predictor of high mortality in OP intoxicated patients which helps in proper allocation of resources

    Breast cancer resistance protein (BCRP) gene expression in a cohort of adult Egyptian patients with acute myeloid leukemia

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    Background: Acute myeloid leukemia (AML), an aggressive clonal disease, is genetically heterozygous. The prognostic role of expression of Breast Cancer Resistance Protein (BCRP) gene, which behaves as a multidrug transporter, in adult AML is ambiguous. Objective: The objective is to assess the level of mRNA expression of BCRP gene in newly diagnosed cytogenetically normal adult Egyptian AML patients; and to clarify its potential influence and association between therapeutic responsiveness and disease free survival.Methods: The BCRP gene expression was evaluated by quantifying its mRNA using real time RT-PCR in fifty newly diagnosed cytogenetically normal adult AML patients and 20 healthy normal controls. The expression was evaluated in relation to clinical and prognostic factors, response to treatment and the survival rate. Results: BCRP mRNA was over expressed in adult AML patients compared to controls. This study showed a positive statistical correlation between BCRP gene expression and the percent of CD34 expression. Statistical analysis did not reveal  any association between BCRP expression level and chemotherapeutic responsiveness or disease free survival rate. Conclusion: The significance of BCRP gene expression and its function in AML is very complicated, therefore more standardized clinical studies are needed.Keywords: BCRP, adult AML, gene expression, prognosis, Egypt

    Inter - Relationship of Awareness, Knowledge, Attitude, Some Socio-Economic Variables and Osteoporosis in Sample of Egyptian Women

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    BACKGROUND: Osteoporosis is a global health problem, and its prevalence is rapidly increasing worldwide. AIM: The aim was to assess the awareness concerning some nutritional and socio-economic variables causes the disease in a sample of Egyptian women. METHODS: This study was done among 116 female volunteers. They were divided into two groups, pre and post-menopausal, with a mean age of 42.05 ± 8.25 &amp; 51.13 ± 5.82 years and mean body mass index (BMI) of 30.83 ± 8.18 &amp; 34.24 ± 8.80 kg/m2. A standardised questionnaire, socioeconomic and food frequency chart were used to assess osteoporosis and food intake awareness. Bone mineral density was measured by dual-energy X-ray absorptiometry (DEXA). Statistical analyses were done using simple percentage and Chi-square test. RESULTS: Data revealed that a low percentage of pre and post-menopausal women were aware of osteoporosis and fracture (16.67% &amp; 12.96% and 30.65% &amp; 19.35%). They had incomplete knowledge about the sources and the beneficial effects of consumption of calcium and vitamin D rich diet. Non-osteoporotic women showed more awareness. Odds ratio predict occupations and educations levels as risk factors for osteoporosis. CONCLUSION: Awareness about osteoporosis and consumption healthy diet were low among Egyptian women, so it is important to implement special osteoporosis prevention program

    Structural and Energetic Properties of Weak Noncovalent Interactions in Two Closely Related 3,6-Disubstituted-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole Derivatives: In Vitro Cyclooxygenase Activity, Crystallography, and Computational Investigations

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    Two 3,6-disubstituted-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole derivatives, namely, 3-(adamantan-1-yl)-6-(2-chloro-6-fluorophenyl)-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole 1 and 6-(2-chloro-6-fluorophenyl)-3-phenyl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole 2, were prepared, and the detailed analysis of the weak intermolecular interactions responsible for the supramolecular self-assembly was performed using X-ray diffraction and theoretical tools. Analyses of Hirshfeld surface and 2D fingerprint plot demonstrated the effect of adamant-1-yl/phenyl moieties on intermolecular interactions in solid-state structures. The effect of these substituents on H···H/Cl/N contacts was more specific. The CLP-PIXEL and density functional theory methods provide information on the energetics of molecular dimers observed in these compounds. The crystal structure of compound 1 stabilizes with a variety of weak intermolecular interactions, including C–H···N, C–H···π, and C–H···Cl hydrogen bonds, a directional C–S···π chalcogen bond, and unconventional short F···C/N contacts. The crystal structure of compound 2 is stabilized by π-stacking interactions, C–H···N, C–H···π, and C–H···Cl hydrogen bonds, and highly directional attractive σ–hole interactions such as the C–Cl···N halogen bond and the C–S···N chalcogen bond. In addition, S(lp)···C(π) and short N···N contacts play a supportive role in the stabilization of certain molecular dimers. The final supramolecular architectures resulting from the combination of different intermolecular interactions are observed in both the crystal packing. The molecular electrostatic potential map reveals complementary electrostatic potentials of the interacting atoms. The quantum theory of atoms in molecules approach was used to delineate the nature and strength of different intermolecular interactions present in different dimers of compounds 1 and 2. The in vitro experiments suggest that both compounds showed selectivity against COX-2 targets rather than COX-1. Molecular docking analysis showed the binding pose of the compounds at the active sites of COX-1/2 enzymes
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