Proposing a rigorous empirical model for estimating the bubble point pressure in heterogeneous carbonate reservoirs

 Bubble point pressure is of great significance in reservoir engineering calculations affecting the success of reservoir simulation. For determining this valuable parameter, experimental tests are the most reliable techniques; however, these measurements are costly and time-consuming. So, it is crucial to propose an empirical model for estimating bubble point pressure. The existing correlations mainly have large errors and develop based on restricted database from a specific geographical location. As a result, development of an all-inclusive correlation is essential. In current article, gene expression programming (GEP) was used to create a generalized model for bubble point pressure estimation. To do this, an all-inclusive source of data was utilized for training and testing the model from the petroleum industry. Several statistical approaches including both illustration tools and diverse error functions were utilized to show the supremacy of the developed GEP model. Consequently, the recommended model is the most accurate as compared to the similar correlations in literature with the average absolute relative error (AARE = 11.41%) and determination coefficient (R2 = 0.96). Furthermore, the solution gas-oil ratio shows to be the most influencing variable on determining bubble point pressure according to sensitivity analysis. The results of contour map analysis demonstrate that most portions of the experimental region are predicted via the GEP equation with fewer errors as compared to two well-known literature correlations. Finally, the proposed GEP model can be of high prominence for accurate bubble point pressure estimation.Cited as: Rostami, A., Daneshi, A., Miri, R. Proposing a rigorous empirical model for estimating the bubble point pressure in heterogeneous carbonate reservoirs. Advances in Geo-Energy Research, 2020, 4(2): 126-134, doi: 10.26804/ager.2020.02.0

The model of workforce agility dependent on drivers, strategies, practices, and results

For the time being, organizations throughout the world are in an environment that is constantly changing in various aspects including technological developments, customers’ preferences, emerging markets, and globalization. In this environment, the concept of agility, especially workforce agility is a valuable tool for organizations and can assist them considerably to cope with this situation. Given a substantial number of scholars have studied the concept of agility from the technical point of view up until now, and have neglected the human resource aspect, this study aims to, first of all, investigate the concept of workforce agility through a model incorporating drivers, practices, strategies advocating and stimulating the implementation of this concept and examine the relationships between these variables and second of all determine the results of implementing workforce agility system. The sample of the present study was selected from the staff and managers of the Ports and Maritime Organization of Iran, who had a bachelor's degree or higher and were working in the field of human resource management. Besides, we used a questionnaire to evaluate the variable. According to the findings, except for the relationship between drivers and implementation results all other relationships between drivers, practices, strategies, and results have been supported

El modelo de agilidad de la fuerza laboral dependiente de los conductores, estrategias, prácticas y resultados

For the time being, organizations throughout the world are in an environment that is constantly changing in various aspects including technological developments, customers’ preferences, emerging markets, and globalization. In this environment, the concept of agility, especially workforce agility is a valuable tool for organizations and can assist them considerably to cope with this situation. Given a substantial number of scholars have studied the concept of agility from the technical point of view up until now, and have neglected the human resource aspect, this study aims to, first of all, investigate the concept of workforce agility through a model incorporating drivers, practices, strategies advocating and stimulating the implementation of this concept and examine the relationships between these variables and second of all determine the results of implementing workforce agility system. The sample of the present study was selected from the staff and managers of the Ports and Maritime Organization of Iran, who had a bachelor's degree or higher and were working in the field of human resource management. Besides, we used a questionnaire to evaluate the variable. According to the findings, except for the relationship between drivers and implementation results all other relationships between drivers, practices, strategies, and results have been supported.         Por el momento, las organizaciones de todo el mundo se encuentran en un entorno que cambia constantemente en varios aspectos, incluidos los desarrollos tecnológicos, las preferencias de los clientes, los mercados emergentes y la globalización. En este entorno, el concepto de agilidad, especialmente la agilidad de la fuerza laboral, es una herramienta valiosa para las organizaciones y puede ayudarlas considerablemente a hacer frente a esta situación. Dado que un número sustancial de académicos han estudiado el concepto de agilidad desde el punto de vista técnico hasta ahora, y han descuidado el aspecto de recursos humanos, este estudio tiene como objetivo, en primer lugar, investigar el concepto de agilidad de la fuerza laboral a través de un modelo que incorpora impulsores. , prácticas, estrategias que propugnan y estimulan la implementación de este concepto y examinan las relaciones entre estas variables y, en segundo lugar, determinan los resultados de la implementación del sistema de agilidad laboral. La muestra del presente estudio fue seleccionada entre el personal y los gerentes de la Organización de Puertos y Marítima de Irán, que tenían una licenciatura o un título superior y trabajaban en el campo de la gestión de recursos humanos. Además, utilizamos un cuestionario para evaluar la variable. Según los hallazgos, a excepción de la relación entre los impulsores y los resultados de la implementación, se han respaldado todas las demás relaciones entre los impulsores, las prácticas, las estrategias y los resultados

The Role of Schema-theory based on Background Knowledge and Graphic Organizer on Enhancing EFL Learners’ Listening Comprehension

The main purpose of this study was to investigate the effect of schema-theory based on background knowledge and graphic organizers on the listening comprehension of EFL learners. Initially, 90 male intermediate learners were selected non-randomly for the purpose of this study. Next, they were given a Nelson Proficiency Test the results of which were drawn upon to select a homogeneous pool of sixty five participants. These participants were then divided into two groups. Following that, a pretest of was administered to the participants of the two groups to make sure that the two groups were not significantly different in terms of listening comprehension performance. Then, as for the first experimental group GO (Graphic Organizer) tasks were used for all the 5 sessions of treatment. As for the second experimental group before listening to the text, the researchers assisted the participants in activating their background knowledge regarding the topic of the listening material. The whole treatment lasted for 5 sessions. Having finished the treatment sessions, both groups sat for the listening posttest. The results of statistical analysis indicated that both schema related activities and graphic organizers led to improvement of the listening comprehension performance of the participants. Moreover, the results of the independent samples t-test on the posttest scores of the two groups indicated that the participants who received graphic organizers as treatment outperformed the participants in the group which received schema related activities on the listening comprehension posttest

Unit Root Volatility Due to Covid-19 Epidemic in the Crude Oil Market

The price of crude oil is one of the most important indicators of the global economy, which is monitored by policymakers, producers, consumers, and participants in financial markets. Oil prices are changing course depending on economic conditions, which is why it is so volatile. The knowledge of researchers, policymakers, and stakeholders about the impact of crises on the oil market provides better control over its negative consequences. Studies show that as a result of various crises, the Volatility Persistence of the oil market is very high. Therefore, it makes sense to consider the hypothesis of a unit root in the Volatility shocks of this market. In the present study, the long-term Volatility Persistence shocks due to the Covid-19 epidemic crisis in the Brent and WTI oil markets, which are the two criteria for determining global oil prices, are investigated using a test proposed by Lee and Yu (2010). The results of this study indicate the existence of a unit root in oil market turbulence. Therefore, the oil market and the economic climate are long-term affected by the effects of this crisis. This can have a significant impact on the revenues of exporting countries and investors in the crude oil sector. Thus, market players and governments need to assess the consequences of this crisis more carefull

Neurological and Vascular Manifestations of Ethylmalonic Encephalopathy

How to Cite This Article: Tavasoli AR, Rostami P, Ashrafi MR, Karimzadeh P. Neurological and Vascular Manifestations of Ethylmalonic Encephalopathy. Iran J Child Neurol. Spring 2017; 11(2):57-60. AbstractObjectiveEthylmalonic encephalopathy (EE) is a severe mitochondrial disease of early infancy clinically characterized by a combination of developmental delay, progressive pyramidal signs, and vascular lesions including petechial purpura, orthostatic acrocyanosis, and chronic hemorrhagic diarrhea. Biochemical hallmarks of the disease are persistently high level of lactate, and C4–C5-acylcarnitines in blood, markedly elevated urinary excretion of methylsuccinic and ethylmalonic (EMA) acids. Here we report two patients with EE as a 16-months-old male infant and a 2-yr-old boy referred to Pediatric Neurology Clinic in Children’s Medical Center, Tehran-Iran that in one patient genetic analysis revealed a homozygous mutation of the ETHE1 gene in favor of ethylmalonic acidemia. References 1. 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Tiranti V, Briem E, Lamantea E, Mineri R, Papaleo E, De Gioia L, et al. ETHE1 mutations are specific to ethylmalonic encephalopathy. J Med Genet 2006; 43:340-346.7. Heberle Lada Cindro LC, Al Tawari Asma A AA, Ramadan Dina G DG, Ibrahim Jamila K JK. Ethylmalonic encephalopathy report of two cases. Brain & Development 2006; 28(5):329–331.8. Mineri R, Rimoldi M, Burlina AB. Identification of new mutations in the ETHE1 gene in a cohort of 14 patients presenting with ethylmalonic encephalopathy. J Med Genet 2008; 45:473-478.9. H.R. Yoon, S.H. Hahn, Y.M. Ahn, S.H. Jang, Y.J. Shin, E.H. Lee, K.H. Ryu, B.L. Eun, P.Rinaldo, S. Yamaguchi. Therapeutical trial in the first three Asian cases of ethylmalonic encephalopathy: response to riboflavin. J Inherit Metab Dis 2001; 24:870–873.10. Maja Di Rocco, Ubaldo Caruso, Egill Briem, Andrea Rossi, Anna E.M. Allegri, Davide Buzzi, Valeria Tiranti. A case of ethylmalonic encephalopathy with atypical clinical and biochemical presentation. 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Chen E, Jurecki ER, Rinaldo P, Keilman C, Packman S, Johnston K. Nephrotic syndrome and dysmorphic facial features in a new family of three affected siblings with ethylmalonic encephalopathy. Am J Hum Genet 1994; 55:A2000.17. Lehnert W, Ruitenbeek W. Ethylmalonic aciduria associated with progressive neurological disease and partial cytochrome c oxidase deficiency. J Inherit Metab Dis 1993; 16:557–559.18. Garavaglia B, Colamaria V, Carrara F, Tonin P, RimoldiM,Uziel G. Muscle cytochrome c oxidase deficiency in two Italian patients with ethylmalonic aciduria and peculiar clinical phenotype. J Inherit Metab Dis 1994; 17:301–303.19. Ozand PT, Rashed M, Millington DS, SakatiN,Hazzaa S, Rahbeeni Z, al OdaibA,Youssef N, Mazrou A,Gascon GG. Ethylmalonic aciduria: an organic acidemia with CNS involvement and vasculopathy. Brain Dev 1994; 16: 12–22.20. Burlina AB, Dionisi-Vici C, Bennett MJ, Gibson KM, Servidei S, Bertini E, Hale DE, Schmidt-Sommerfeld E, Sabetta G, Zachello F, Rinaldo P. A new syndrome with ethylmalonic aciduria and normal fatty acid oxidation in fibroblasts. J Pediatr 1994; 125:79–86. 

Application of a new approach for modeling the oil field formation damage due to mineral scaling

International audienceMineral scaling has been considered a great concern for developing the oil production from the underground petroleum reservoirs. One of the main causes of this phenomenon is known as the chemical incompatibility of injected brine, frequently sea water, with the reservoir brine leading to the deposition of various supersaturated salts such as calcium carbonate, calcium sulfate and barium sulfate. In present communication, an evolutionary approach namely, Gene Expression Programming (GEP), was employed for rigorous modeling of formation damage by mineral scaling of mixed sulfate salt deposition. At first, a large databank of damaged permeability datapoints as a function of injected volume, injection flowrate, temperature, differential pressure and ionic concentrations of the existing chemical species in the porous media was employed. In this regard, a user-friendly correlation was extended for the first time by the aforementioned technique in the literature. Professional evaluation of the suggested GEP-based model was implemented by different statistical parameters and appealing visualization tools. Having proposed the GEP-based correlation, statistical parameters of the Average Absolute Relative Deviation Percent (AARD%) of 0.640% and determination coefficient (R2) of 0.984 was calculated. Accordingly, it is demonstrated that the proposed model has a superior performance and great potential for efficient prediction of damaged permeability due to the mixed sulfate salt scaling. Moreover, the implemented outlier diagnosis technique verified the validity of the databank used for modeling, as well as the high robustness of the suggested model was confirmed. In conclusion, the developed correlation in this work can be of enormous practical value for skillful engineers and scientists in any academic study and industrial applications dealing with mixed salt deposition

Assessment of the Microbiome Role in Skin Protection Against UV Irradiation Via Network Analysis

Introduction: Diverse microbiotas which have some contributions to gene expression reside in human skin. To identify the protective role of the skin microbiome against UV exposure, protein-protein interaction (PPI) network analysis is used to assess gene expression alteration.Methods: A microarray dataset, GEO accession number GSE117359, was considered in this respect. Differentially expressed genes (DEGs) in the germ-free (GF) and specific pathogen-free (SPF) groups are analyzed by GEO2R. The top significant DEGs were assigned for network analysis via Cytoscape 3.7.2 and its applications.Results: A total of 28 genes were identified as significant DEGs and the centrality analysis of the network indicated that only one of the seven hub-bottlenecks was from queried genes. The gene ontology analysis of Il6, Cxcl2, Cxcl1, TNF, Il10, Cxcl10, and Mmp9 showed that the crucial genes were highly enriched in the immune system.Conclusion: The skin microbiome plays a significant role in the protection of the skin against UV irradiation and the role of TNF and IL6 is prominent in this regard

Application of nanofluids for treating fines migration during hydraulic fracturing: Experimental study and mechanistic understanding

 Hydraulic fracturing has emerged as one of the best and most economic methods for enhancing oil recovery from low permeability reservoirs such as shale gas reservoirs. However, its performance will be negatively affected by fines migration due to hydraulic fracturing process. In the present study, it has been tried to experimentally investigate the efficiency of a synthesized Nanosilica particles in reducing fines migration for the first time in literature. To this end, two sets of static and dynamic experiments, namely glass bead funnel test and core displacement analysis, were implemented, respectively. In the static test, increasing the soaking time and addition of Nanosilica led to the clearer effluent fluid, resulting in less concentrations of clay particles in solution. When the mixture of Nanosilica and glass beads was available in the solution, a higher differential pressure was obtained during dynamic condition in comparison to only glass beads, which means the lower permeability of the porous media. Moreover, DLVO theory was applied to demonstrate the clay particles absorption on the sand proppants surfaces.  Consequently, it was observed that the use of Nanosilica particles mixed with sand proppant can effectively reduce fines migration; thereby, it can enhance hydraulic performance of the fracturing operation.Cited as: Moghadasi, R., Rostami, A., Hemmati-Sarapardeh, A. Application of nanofluids for treating fines migration during hydraulic fracturing: Experimental study and mechanistic understanding. Advances in Geo-Energy Research, 2019, 3(2): 198-206, doi: 10.26804/ager.2019.02.0