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167 results on '"Omar, Ayman"'

12. Selected aspects of price formation in commodity markets

Author

Omar, Ayman M. A. A., Wisniewski, Tomasz, and Nolte, Sandra

Subjects
658
Abstract

The thesis is driven by the strategic importance of crude oil, and aims to contribute to the knowledge on crude oil pricing and markets by conducting three investigative undertakings. The first examines the ability of crude petroleum to act as a safe haven asset for investors in equity markets around the start of international violent conflicts and wars. The second investigates the price differentials between US domestic benchmark crudes and the global marker Brent around the start of upstream production disruptions. The third empirical examination explores the presence of abnormal behaviour in the vicinity of the start dates of US sanctions on net exporting and importing nations, and builds on these findings to estimate gains accrued to, and losses inflicted on, the US economy. The thesis reports a number of findings. First, it shows that crude oil prices register a significant abnormal rise around the start of violent conflicts and wars. The significant portion of this abnormal increase accumulates well before the outbreak of crises. The thesis also reports a significant abnormal decline in the valuations of US and international equities around the start of these events. Secondly, the thesis builds on these findings, and demonstrates that crude oil possesses the ability to act as a safe haven from stock markets around the start of these events. Third, the thesis reports significant tightening in the price spreads around the start of unscheduled production outages. These findings are shown to be robust even after accounting for extreme weather conditions, changes in petroleum stocks, and costs of logistics. Fourth, the thesis reports significant abnormal changes in the valuations of crude oil around the start of US sanctions. The direction and magnitude of these changes depend on whether the targeted nation is a net exporter or importer. Fifth, the thesis builds on these findings, and reports gains and losses to the US economy due to the imposition of sanctions. These findings contribute to the academic literature, and highlight a number of implications for equity investors, insurance companies, oil traders, and policy makers in the US and other net importing and exporting nations. These implications concern the energy security of the US and other nations, the use of oil in hedging and diversification, the role of benchmarks in pricing, and the economic consequences of the US foreign policy.

Published
2016

34. A behavioral theory of sustainable supply chain management decision making in non-exemplar firms

Author

Kirchoff, Jon F., Omar, Ayman, and Fugate, Brian S.

Subjects
Sustainable development -- Analysis, Decision-making -- Analysis, Logistics -- Analysis, Business, general, Business
Abstract

Empirical evidence shows that investments in sustainable supply chain management can improve economic-based performance. Thus, based on standard economic theory, rational business decision makers should and will implement sustainable supply chain management practices. However, through inductive research methods, we uncovered an intriguing theme that runs counter to both the existing empirical evidence and such economic-based assumptions. We find that managers operating in firms without exemplary sustainable supply chain management practices face immense hurdles in developing a business case for implementing sustainability initiatives. Despite the lack of such practices--and in tension with the prevailing empirical evidence and theory--the firms within which these managers operate were performing well on economic-based performance metrics. Departing from the neoclassical economic theory of the firm, we apply the Behavioral Theory of the Firm's theoretical assumptions to findings which suggest four segments of managers in non-exemplary firms who vary based primarily on how they perceive strategic vulnerability, evaluate choices, and utilize sustainability knowledge. Keywords: sustainable supply chain management; human judgment and decision making; environmental issues; social responsibility; grounded theory; qualitative data analysis; behavioral theory of the firm, INTRODUCTION The debate on whether or not a strong business case exists for developing and implementing socially and environmentally sustainable practices has attracted considerable attention from practitioners and academics. In [...]

Published
2016

35. Health Consequences of Obesity: A Review

Author

Alsudairy, Najlaa Mohammad, primary, Alameer, Wafa Hamad M., primary, Alattas, Ohoud Ali A., primary, Altalhi, Marwan Abdulmalik Modkel, primary, Alghraibi, Ahmad Mohammed A., primary, Kanoori, Elaf Abdulkader, primary, Alharbi, Abdulrahman Khulaif, primary, Yumen, Lujain Mohamed, primary, Altowairqi, Rawan Mohammed M., primary, Alghamdi, Saleh Ali, primary, Alqahtani, Osama Hassan, primary, Omar, Ayman Mohamed, primary, Alzuwayed, Anas Mohammad, primary, and Bajebair, Abdullah Mohammed A., primary

Published
2021
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36. SYNERGISTIC EFFECTS OF PLANT GROWTH PROMOTING RHIZOBACTERIA IN IMPROVEMENT THE CROP PRODUCTION AND SUSTAINABLE AGRICULTURE.

Author

Omar, Ayman F., Rehan, Medhat, and Al-Turki, Ahmad

Abstract

The population growth is one of the most important global problems that researchers must overcome. So, application of plant growth promoting rhizobacteria (PGPR) can play a significant role in enhancing the agricultural production through facilitating water and nutrient uptake for plants under various conditions as an important and alternative strategy to overcome overpopulation all over the world. Plant growth promoting rhizobacteria can used as low-cost and environmentally safe biofertilizer to improve crop growth and development by regulating hormonal balance, maintaining nutrients and producing plant growth regulators, however, the chemical fertilizers can harm the ecosystem and human health severely. PGPR treatments may positively affect physiological, biochemical and anatomical features resulting in improve various morphological characters such as number of leaves, leaf area and stem height. Additionally, chlorophyll a and b, carotenoids, relative water content (RWC), antioxidant enzymes and plant hormones as well as crop yield were increased in many plants with the application of PGPR. Moreover, application of PGPR led to improve the anatomical characters of stems and leaves such as stem diameter, lamina thickness, phloem thickness, xylem vessels diameter and number of xylem vessels. Previous studies also reported that PGPR can mitigate the adverse effects of several biotic and abiotic stresses resulted in improve plant growth and yield in many stressed plants. This review article gives an overview on the impacts of PGPR in enhancing morphological, physio-biochemical and anatomical characters through improving the antioxidant enzymes activity, producing plant hormones and consequently crop production. [ABSTRACT FROM AUTHOR]

Published
2022

37. Factors Accelerating Recovery of Intestinal Motility after Radical Cystectomy with Urinary Diversion

Author

Mohamed A. Omar Ayman A. Hassan, Mohamed A. Elbendary, and Mohamed A. Refat Tarek A. Gameel

Subjects
medicine.medical_specialty, Bladder cancer, Ileus, business.industry, medicine.medical_treatment, Urinary system, Urinary diversion, Urology, Soft diet, Perioperative, medicine.disease, Group B, Cystectomy, medicine, business
Abstract

Background: Radical cystectomy (RC) with urinary tract reconstruction currently remains the gold standard treatment for invasive bladder cancer. RC associated with many com-plications, postoperative ileus is the most common one which lead to increasing length of hospital stay. Multiple perioperative care plans was put aimed to decrease POI.Aim of Study: Evaluation of the different factors that can help to accelerate recovery of intestinal motility after radical cystectomy and urinary diversion in order to decrease the length of hospital stay.Patients and Methods: A total of 37 patients who under-went radical cystectomy with urinary diversion using intestinal segments were divided into 2 groups. In group A (n=23), our new protocol of perioperative preparation applied, in group B (n=14) classic way of perioperative preparation applied. The main differences between both ways are one day intestinal preparation with use of fortrans preoperative, anal dilatation intraoperative and chewing gums postoperative.Results: There was statistical significance in first intestinal sound first passage of flatus, beginning of soft diet, time to regular diet and hospital stay in favor of group A as compared to the group B (p-value

Published
2019

38. BACTERIAL LEAF SPOT DIESASE OF PEPPER CAUSED BY Xanthomonas axonopodis IN SAUDI ARABIA: IDENTIFICATION AND BIOCONTROL USING Streptomyces sp. In-Vitro.

Author

Omar, Ayman F., Rehan, Medhat, and Al-Turki, Ahmad

Abstract

Xanthomonas genus causes lesions on plant leaves, stems, and fruits. Xanthomonas campestris is considered as one of the most devastating pathogens that infects pepper and tomato worldwide. Traditionally the Xanthomonas disease are controlled by using chemicals control methods that possess numerous demerits. There is a need to develop an effective and safe biocontrol strategies to control these diseases. The present work was aimed to isolate and identify Xanthomonas sp. from infected pepper plants and to develop a suitable biocontrol agent. In the present study we report four new isolates of X. axonopodis from infected pepper plants. Based on 16S rDNA homology, these isolates were identified as X. axonopodis QXP1, X. axonopodis QXP2, X. axonopodis QXP3, and X. axonopodis QXP5. These isolates were able to cause the re-infections in pepper plant. Eight strains of Streptomyces sp. were tested for their biocontrol activity against Xanthomonas isolates. Streptomyces tricolor strain HM10 exhibited potent biocontrol activity against the tested pathogens. To the best of our knowledge, this is the first report regarding the isolation X. axonopodis from pepper plants. [ABSTRACT FROM AUTHOR]

Published
2022

40. Impact of Pathologic Complete Response following Neoadjuvant Chemotherapy ± Trastuzumab in Locally Advanced Breast Cancer

Author

Al-Tweigeri, Taher, primary, Elshenawy, Mahmoud, additional, Badran, Ahmed, additional, Omar, Ayman, additional, Suleman, Kausar, additional, Al Malik, Osama, additional, Anwar, Ihab, additional, Jastaniya, Noha, additional, Tulbah, Asma, additional, Al Shabanah, Mohammad, additional, Ajarim, Dahish, additional, and Al Sayed, Adher, additional

Published
2021
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42. Assessing Frequency and Clinical Outcomes of BRCA Mutated Ovarian Cancer in Saudi Women

Author

Agha, Naela, primary, Alshamsan, Bader, additional, Al-Farsi, Sharifa, additional, Ateya, Heba Aly, additional, Almugbel, Fahed A, additional, Alotaibi, Hazem Abdullah, additional, Omar, Ayman, additional, Mohamed, Amgad Shahin, additional, Alharthy, Hanan, additional, Elhassan, Tusneem, additional, Salem, Hany, additional, and Alhussainia, Hamed, additional

Published
2021
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43. Assessing Frequency and Clinical Outcomes of BRCA Mutated Ovarian Cancer in Saudi Women

Author

Agha, Naela, primary, Alshamsan, Bader, additional, Al-Farsi, Sharifa, additional, Ateya, Heba Aly, additional, Almugbel, Fahed A, additional, Alotaibi, Hazem Abdullah, additional, Omar, Ayman, additional, Mohamed, Amgad Shahin, additional, Alharthy, Hanan, additional, Elhassan, Tusneem, additional, Salem, Hany, additional, and Alhussainia, Hamed, additional

Published
2020
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44. Trastuzumab, Pertuzumab, and Docetaxel as the First Line for HER-2-Positive Metastatic Breast Cancer among Arabs

Author

Suleman, Kausar, primary, Mushtaq, Ali Hassan, additional, Haque, Emaan, additional, Badran, Ahmed Ali, additional, Ajarim, Dahish, additional, Elashwah, Ahmed Mohammed, additional, Gad, Ahmed Mostafa, additional, Abdelsamad, Amgad Shaheen, additional, Omar, Ayman, additional, Khan, Khurshid Ahmed, additional, Al-Tweigeri, Taher, additional, Elshentenawy, Ayman, additional, and Alsayed, Adher, additional

Published
2020
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49. Tribulus terrestris versus placebo in the treatment of erectile dysfunction and lower urinary tract symptoms in patients with late-onset hypogonadism: A placebo-controlled study

Author

Omar Ayman Saadeldin, Sameh Fayek GamalEl Din, Ahmed Ragab Ahmed, Mohamed Ahmed Abdel Salam, Ramzy Raafat Elnabarway, Ahmed Tarek Motawaa, and Mohamed Shokr Mohamed

Subjects
Adult, Male, medicine.medical_specialty, Tribulus terrestris, Protodioscin, 030232 urology & nephrology, Gastroenterology, 03 medical and health sciences, chemistry.chemical_compound, 0302 clinical medicine, Erectile Dysfunction, Lower Urinary Tract Symptoms, Lower urinary tract symptoms, Internal medicine, Androgen deficiency, medicine, Tribulus, Outpatient clinic, Humans, Single-Blind Method, Prospective Studies, Aged, 030219 obstetrics & reproductive medicine, business.industry, Hypogonadism, Age Factors, General Medicine, Middle Aged, medicine.disease, Erectile dysfunction, Treatment Outcome, chemistry, International Prostate Symptom Score, business, Sexual function, Phytotherapy
Abstract

Aging is associated with a series of morphological and functional modifications that leads to reduced physiological efficiency and atrophy of various organs and systems. Tribulus terrestris induces its effect in fertility and sexual functions through the steroidal saponins, particularly the dominant saponins protodioscin. We aimed in this study to evaluate the efficacy and safety profiles of Tribulus terrestris in aging males with partial androgen deficiency who suffered from erectile dysfunction and lower urinary tract symptoms. A total of 70 randomized aging patients with erectile dysfunction and lower urinary tract symptoms were recruited from June 2017 to March 2018 from our andrology outpatient clinic. Thirty-five patients (group A) received Tribulus terrestris three times daily for 3 months and the other 35 patients (group B) received placebo. The mean of aspartate transaminase was elevated in group A after 3 months of receiving Tribulus terrestris (26.5 (before), 27.8 (after), respectively, p = 0.03). Moreover, there were significant elevations in the means of both total testosterone together with the score of the validated Arabic index of erectile function (5-item version of the International Index of Erectile Function) (2.2, 10.7 (before), 2.7, 16.1 (after), p

Published
2018

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