Miracle-dz/UniFAR-FTUs huggingface dataset:
Crude Oil Prices and COVID-19: Persistence of the Shock

The effect of the COVID-19 crisis on crude oil prices is investigated by using long memory techniques. The oil price series is highly persistent with an order of integration of 0.84, displaying mean reversion. When we examine data before the onset of COVID-19, the first order integration hypothesis cannot be rejected. The results are consistent with evidence of market efficiency prior to the crisis, with the oil market becoming inefficient when incorporating the data covering the crisis. The evidence that oil price series is mean reverting implies that the shock will be transitory albeit with very long-lasting effects.
Plasmonic effects of copper nanoparticles in polymer photovoltaic devices for outdoor and indoor applications

The use of metal nanoparticles (NPs) that can trigger localized surface plasmon resonance (LSPR) is an effective method for improving the performance of organic photovoltaics (OPVs). Currently, most plasmonic NPs are based on noble metals, including gold and silver; their high cost limits their commercial applications in the cost-effective OPVs. Herein, copper (Cu) NPs, which are more abundant and cheaper, are adopted to fabricate OPVs. To avoid oxidation of Cu NPs, they are positioned at the cathode interface, so that their fabrication could be implemented in an inert environment. The resulting OPVs exhibited improved power conversion efficiencies (PCEs) under illumination at 1 sun, and the device enhancement could be attributed to the LSPR effects of Cu NPs. Further, their potential to enhance the performance of OPVs under indoor lighting conditions is evaluated. The enhancement factor of PCEs was higher, while the light source had a lower color temperature. It could be due to the fact that the main plasmonic band of the Cu NPs is localized in the red spectral range. The results reveal the consideration of matching between the LSPR spectral range and the emission spectra of the artificial light sources is very critical for indoor applications.
Contextualizing The Framework For Knowledge Management System At The Organizational Level

Formulation of knowledge management system (KMS) is significance to support knowledge management activities within organizations; moreover, information technology has become the driving factors for business strategies and directions. In the past studies, the focus of KMS establishment are diverse; ranging from its successful adoption, perceived usefulness of the users or on its supporting roles in organization strategy to improve their performance and smooth operations. Despite its benefits to the organization, however, gap has been identified on the lack of existence and definition of KMS framework at the organizational level studied by other researchers. Thus, the objective of this study is to formulate the KMS framework at the organizational level known as OKMS (organization-based knowledge management system). This study is performed by methodologically conducting a review and analysis of the past literature and related areas of concern on establishment of KMS. Outcome of this study will not only help to motivate for other future empirical and theoretical research for KMS at the organization level, but, it also provide a departing point for other KMS researches establishment for organizations.
The Effect of the Board of Directors’ Characteristics on Company Value

This study aims to analyze the influence of the characteristics of the board of directors on company value. The characteristics of the board of directors are measured by size, age, and activities on company values. The samples of this research were taken randomly from 266 companies listed in the Indonesia Stock Exchange during 2011-2017. The results of this study indicate that the size of board of directors has a negative and significant effect on company value. However, age and activities of the board of directors and company growth do not have a significant effect on company value. Meanwhile, company leverage has a positive and significant effect on company value.
Bien choisir son outil d’extraction de contenu à partir du Web (Choosing the appropriate tool for Web Content Extraction )

Nous proposons une démonstration sur l’extraction de contenu textuel dans des pages web ainsi que son évaluation. Nous nous concentrons sur les pages web contenant du texte (articles de presse, magazines en ligne et blogs) et montrons que les textes peuvent varier grandement selon différentes dimensions : diachronique, géographique et typologique. Dès lors, les outils et mesures d’évaluation correspondantes sont sujettes à caution : les indicateurs communément utilisés et censés présider au choix de l’outil approprié par les utilisateurs finaux sont à la fois imprécis et difficiles à interpréter.
Critical Factors Affecting the Salaries of Employees of Manufacturing Enterprises in Vietnam

The study aims to identify and measure factors affecting the salaries of employees in manufacturing enterprises in Hanoi, the important area of Vietnam’s economy. We conducted a questionnaire consisting of 31 observation variables with a 5-point Likert scale. Independent variables were measured from 1 “without effect” to 5 “strongly”. Based on the literature review and results of interviews, a total of 350 questionnaires were sent to participants; 300 of them met the standards and were subject to be analyzed. The results of Exploratory Factor Analysis (EFA) and Multiple Regression Analysis (MRA) identify six main determinants influencing the salaries of employees in manufacturing enterprises in Hanoi, including Paying views of business leaders (PV), Financial ability of the enterprise (FA), Capacity of workers (CW), Capacity of the contingent of employees engaged in salary work (CC), Role of grassroots trade unions (TU), and State policies and laws on labor – salaries (STL). Based on the findings, some recommendations have been proposed to help the firm leaders design appropriate personnel policies for creating better job satisfactions for employees in the future. On this basis, the authors propose a number of recommendations to improve the salaries of employees in manufacturing enterprises in Hanoi.
Emotional Evaluation of Homelike Residence Halls Using Self-Assessment Manikins

Students’ residence halls have been studied repeatedly during the last decades from various perspectives (eg satisfaction). However, our knowledge is very limited in terms of students’ emotions towards various residence hall interior and exterior spaces. Besides, very little study exists on the impact of homelike furniture on students’ emotions. The question driving this research is whether the replacement of institutional furniture with home like furniture affects students’ emotional states towards their residence hall? The research follows a mixed, multi-staged methodology. Stage one used structured interviews of students about what might make a residence hall similar to home environments. This second stage evaluates students’ emotions toward their current residence halls (with institutional furniture) and modified images of the same place with homelike furniture. We used SAM to evaluate students’ emotional reactions in terms of valence, arousal, and dominance. The findings of the study suggests that home like residence halls significantly affect students’ positive emotions. The most positive emotions (valence, arousal, and dominance) were reported on kitchenette, corridor, and yard spaces and no significant differences were found on in-room décor.
Markov-Switching Stochastic Processes in an Active Trading Algorithm in the Main Latin-American Stock Markets

In the present paper, we review the use of two-state, Generalized Auto Regressive Conditionally Heteroskedastic Markovian stochastic processes (MS-GARCH). These show the quantitative model of an active stock trading algorithm in the three main Latin-American stock markets (Brazil, Chile, and Mexico). By backtesting the performance of a U.S. dollar based investor, we found that the use of the Gaussian MS-GARCH leads, in the Brazilian market, to a better performance against a buy and hold strategy (BH). In addition, we found that the use of t-Student MS-ARCH models is preferable in the Chilean market. Lastly, in the Mexican case, we found that is better to use Gaussian time-fixed variance MS models. Their use leads to the best overall performance than the BH portfolio. Our results are of use for practitioners by the fact that MS-GARCH models could be part of quantitative and computer algorithms for active trading in these three stock markets.
Methane Hydrate Formation, Storage and Dissociation Behavior in Unconsolidated Sediments in the Presence of Environment-Friendly Promoters

Methane hydrate in the porous medium is formed within the pores of the sediments. The presence of a porous medium enhanced the heat transfer, whereas the presence of a hydrate promoter could enhance the mass transfer between the liquid-gas interface. In this study, we have studied the effect of sediment particle size and type of promoter on the kinetics of the methane hydrate formation and dissociation in the combined system. Environment-friendly amino acids (L-valine, L-methionine & L-histidine) and surfactant Sodium dodecyl sulfate are used as a promoter with four different particle sizes (46.4-245 μm, 160-630μm, 480-1800μm, 1400-5000μm) silica sand. Isothermal experiments are carried out using 3000 ppm promoter concentration at 100 bar, 274.15°C using the rocking cell to investigate the induction time, gas uptake, hydrate saturation. Temperature is further lowered to 266.15K to investigate the dissociation behavior of methane hydrate to study the self-preservation effect in the combined system. The experimental results show that induction time in the combined system decreases as a sediment particle size decreases. Gas uptake remained unchanged in the combined system by changing the sediment particle size. We also report similar formation kinetics of hydrophobic amino acids (L-valine, L- methionine) and SDS at four particle sizes. At similar hydrate saturation, SDS has displayed weaker self- preservation effects compare to a hydrophilic amino acid in the porous medium. Results in this study, support the conclusion available through other studies at lower concentration (500 ppm) of SDS and provide additional information about formation behavior at higher concentration (3000 ppm) of SDS. Results collected in this research could be beneficial in the selection of environmentally friendly chemicals for rapid methane hydrate formation in sediments to be used either in laboratory studies or for natural gas storage and transportation.
Traffic Incident Clearance Time Prediction and Influencing Factor Analysis Using Extreme Gradient Boosting Model

Accurate prediction and reliable significant factor analysis of incident clearance time are two main objects of traffic incident management (TIM) system, as it could help to relieve traffic congestion caused by traffic incidents. This study applies the extreme gradient boosting machine algorithm (XGBoost) to predict incident clearance time on freeway and analyze the significant factors of clearance time. The XGBoost integrates the superiority of statistical and machine learning methods, which can flexibly deal with the nonlinear data in high-dimensional space and quantify the relative importance of the explanatory variables. The data collected from the Washington Incident Tracking System in 2011 are used in this research. To investigate the potential philosophy hidden in data, K-means is chosen to cluster the data into two clusters. The XGBoost is built for each cluster. Bayesian optimization is used to optimize the parameters of XGBoost, and the MAPE is considered as the predictive indicator to evaluate the prediction performance. A comparative study confirms that the XGBoost outperforms other models. In addition, response time, AADT (annual average daily traffic), incident type, and lane closure type are identified as the significant explanatory variables for clearance time.
Synthesis and analysis of Mg–3%Al alloy nanocomposites reinforced by RGO

ABSTRACT Graphene and its derivatives, due to their extraordinary mechanical, thermal, and tribological properties, are extensively used to fabricate bulk graphene-based nanocomposites. On the other hand, magnesium alloys are lightweight and manifest excellent mechanical properties. In the present study, the hardness and compressive responses of Mg–3 wt%Al/xRGO (x = 0.1 wt% and 0.3 wt.%) nanocomposites at ambient temperature were investigated. Further, the coefficient of thermal expansion of Mg–3 wt%Al/xRGO (x = 0.1 wt% and 0.3 wt.%) nanocomposites at elevated temperatures were estimated and compared with those of pure Mg and Mg–3 wt%Al alloy. Reduced graphene oxide (RGO) synthesized through the improved Hummer’s Method followed by the thermal reduction method was used as the reinforcement material. The bulk samples of pure Mg, Mg–3%Al alloy, and nanocomposites were synthesized by blending of Mg, Al and RGO powder followed by cold compaction, microwave sintering and hot extrusion. Nanocomposite samples displayed significant changes in microstructures and substantial improvements in both Vickers hardness and ultimate compressive strength. The lower thermal expansion coefficients of Mg–3%Al/xRGO (x = 0.1 wt% and 0.3 wt.%) nanocomposites demonstrated better thermal and dimensional stability with respect to temperature. The obtained results would be conducive to design lightweight structural materials.
Antimicrobial Poly (methyl methacrylate) with Silver Nanoparticles for Dentistry: A Systematic Review

Poly(methyl methacrylate) (PMMA) is a widely used polymer for dental applications, and it is mainly used in the fabrication of dental prostheses. In an increasing number of these applications, the risk of suffering bacterial or fungal infection is higher than 60% among oral-prosthesis users. Some authors have reported the failure of other implants in the human body due to biofilm formation on the surface (mainly for total hip implants). In the dental field, the formation of bacterial and fungal biofilms on prosthesis’s surface is the etiologic factor for stomatitis, mainly caused by Candida albicans and bacteria such as Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa and Enterococcus faecalis, as well as many others. The antibacterial and antifungal properties of silver nanoparticles (AgNPs) have been widely reported, and their use in dental materials can prevent oral infections, such as candidiasis and stomatitis, and promote better oral health in dental-prosthesis users. They can even be used in other biomedical applications that require controlling biofilm formation on surfaces. In this review, the reported studies that use composites of PMMA and AgNPs (PMMA-AgNPs) for dental applications are listed and checked, with the aim of gaining a wider perspective of the use and application of this approach in the dental field.
The stakeholder challenge: dealing with challenging situations involving stakeholders

Abstract Project managers are an occupational group who is exposed to high levels of stress caused by various aspects such as resources and communication or working relationships. One particularly challenging area is the interaction with stakeholders, who are often perceived to ‘be difficult’. With this study, we investigate how project managers cope with challenging situations involving stakeholders in projects. We do this through a qualitative study involving interviews and focus groups to explore the lived experiences of the project managers in specific situations. Our findings suggest that a project manager perspective on stakeholder management is particularly valuable to account for contextual factors such as sources of challenging situations. We propose a project coping model which transfers Lazarus and Folkman’s stress and coping model into the project context and adds the layer of project coping to emphasise the project managers’ perception of accountability and commitment to the project.
Évaluation d'un nouveau milieu de culture pour la recherche de Listeria monocytogenes dans le lait cru

Depuis les dernieres epidemies de listeriose humaine, un grand nombre de milieux de culture et de techniques ont ete developpes pour detecter la presence de Listeria dans les aliments. Actuellement, les methodes appliquees dans le cadre des analyses de routine ne permettent pas la mise en evidence de Listeria monocytogenes directement a partir du milieu d'isolement, la discrimination entre L. monocytogenes et les autres Listeria etant difficile a ce stade. L'objectif de notre etude est d'evaluer le milieu EHA (enhanced haemolysis agar), qui met en evidence une hemolyse amplifiee et rend possible un reperage precoce de L. monocytogenes.
A new species of Stemonitis pseudoflavogenita from Russia, and the first record of Stemonitis capillitionodosa in Eurasia

This paper reports a new Stemonitidaceae species, Stemonitis pseudoflavogenita, found in Krasnodar Territory and Novosibirsk Region of Russia. We provide morphological and molecular characterization of S. pseudoflavogenita and data on its distribution and habitat. Compared to other representatives of the genus Stemonitis, S. pseudoflavogenita and three other species of this genus (S. capillitionodosa, S. flavogenita, and S. sichuanensis) have thickening and widening of the column apex, which makes them a separate morphological group. However, the above three known species have warted and spinulose spore ornamentations, S. pseudoflavogenita shows complex ornamentation consisting of large warts and a few small warts irregularly scattered among the large ones and small indentations on the spore surface. Stemonitis capillitionodosa is a rare myxomycete. We found and retrieved the specimens of Stemonitis capillitionodosa from the Laplandskiy Biosphere Reserve (Murmansk Region, Russia), the first record of this species in Eurasia. We present a scanning electron microscopic study of both S. pseudoflavogenita and S. capillitionodosa. New sequences for SSU rDNA of S. pseudoflavogenita and S. capillitionodosa were obtained.
Ecology, Phylogeny, and Potential Nutritional and Medicinal Value of a Rare White “Maitake” Collected in a Mediterranean Forest

Albino Grifola frondosa (Dicks.) Gray “maitake” mushrooms (described as G. albicans Imazeki and then placed in synonymy with G. frondosa) are particularly rare, and the few pertinent records are not treated in scientific publications. A field investigation carried out in Sicily (Italy) led to the collection of an unusual white Grifola specimen at the base of a living tree of Quercus pubescens Willd. s.l. The outcome of sequencing the internal transcribed spacer (ITS) region of nuclear ribosomal DNA (nrDNA) indicated that it belongs to G. frondosa and provided an insight to the phylogenetic relationships within the genus. The results of nutritional composition analysis showed that the albino basidioma possesses relatively high contents of Ca, Fe, K, and Cu and is rather low in Na when compared with literature data on edible mushrooms. Vitamin (B1, B2, B3, B5, B9, and D2) contents ranged from 0.15 to 3.89 mg per 100 g of mushroom dry weight. The cold-water extract of this specimen was effective at inhibiting the growth of Staphylococcus epidermidis ATCC 12228 and Pseudomonas aeruginosa ATCC 15442 at the maximum screening concentration of 50% v/v. In addition, the extract slowed down the ability of Staphylococcus aureus ATCC 43300 to form biofilms. According to data hereby reported, the albino G. frondosa is a culinary-medicinal mushroom with a promising exploitation potential.
Interactions of metal and metalloid ions with fungal biomass

In theory, the higher the covalent index value of a metal ion, the greater its potential to form covalent bonds with biological ligands. Metabolism-independent equilibrium metal ion adsorption to freeze dried Rhizopus arrhizus biomass was found to increase in the order Sr2+ < Mn2+ < Zn2+ < Cd2+ < Cu2+ < Pb2+ and positively correlated with covalent index. Adsorption was rapid and 95% complete within five minutes of metal-microbe contact, and equilibrium was independent of solution biomass concentrations. The potential of a metal to displace other preloaded cations from the biomass ligands, and the extent to which a preloaded ion inhibited the adsorption of another both increased with increasing covalent index for Mn2+, Zn2+, Cd2+, Cu2+ and Pb2+. An almost complete inversion of this order was observed in the case where Sr2+ was the primary binding test ion. According to the hard and soft principle of metal ions, Mn2+, Zn2+, Cd2+, Cu2+ and Pb2+ are classified as soft-borderline, Sr2+ is classified as hard, and theoretically the polar nature of these cations increase in the same order as covalent index. As a consequence of metal ion adsorption, Ca2+ and Mg2+ displacement from the biomass ligands was observed for both hard and soft borderline ions, whereas displacement of H+ was observed for soft borderline ions only. Overall, the soft borderline ions exhibited a significant degree of both covalent and ionic binding, and the hard metal Sr2+ was found to exhibit ionic binding only. Linear reciprocal Langmuir and Scatchard transformation plots reflected the predominantly ion exchange mechanism of Sr2+ and Cd2+ adsorption, and a curved Scatchard transformation plot reflected the more covalent nature of Cu2+ adsorption. The transformation and accumulation of the oxyanion selenite (1000 |imol I'1) by a growing Penicillium species was investigated over a 2 week period. Selenium in the aqueous phase decreased by ca. 49.8%, and selenium accumulated by the fungal biomass totalled ca. 36.6%. Transformation into volatile selenium compounds amounted to an average value of ca. 8.8%, and the process was determined to be both growth and nongrowth associated. Activated charcoal traps were successfully used to retain the volatile selenium compounds which were determined to be organic in nature. The reduction of selenite to amorphous elemental selenium was observed only during the decline phases of growth. Selenite transformation, particularly reduction to amorphous elemental selenium, was enhanced by the addition of amino acids and vitamins to the aqueous medium, and with such amendments selenite reduction was observed both during the rapid and stationary phases of growth.
Cell Membrane Stability as a Measure of Heat Tolerance in Hexaploid and Tetraploid Wheat

A comparison was made of the physiological and morphological differences between Inqlab-91 (hexaploid) and Langdon (tetralpoid) wheat genotypes in response to high temperature stress applied at third leaf stage of growth. Electrolytes leakage technique was used to detect differences in the heat sensitivities of leaves of Inqlab-91 and Langdon. This method showed that at both 35 or 40°C Inqlab-91 was more heat tolerant than Langdon.