Air pollution is considered one of the biggest threats for the ecological system and human existence. Therefore, air quality monitoring has become a necessity in urban and industrial areas. Recently, ...the emergence of Machine Learning techniques justifies the application of statistical approaches for environmental modeling, especially in air quality forecasting. In this context, we propose a novel feature ranking method, termed as Ensemble of Regressor Chains-guided Feature Ranking (ERCFR) to forecast multiple air pollutants simultaneously over two cities. This approach is based on a combination of one of the most powerful ensemble methods for Multi-Target Regression problems (Ensemble of Regressor Chains) and the Random Forest permutation importance measure. Thus, feature selection allowed the model to obtain the best results with a restricted subset of features. The experimental results reveal the superiority of the proposed approach compared to other state-of-the-art methods, although some cautions have to be considered to improve the runtime performance and to decrease its sensitivity over extreme and outlier values.
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•Forecasting multiple air pollutant concentrations simultaneously.•The combination of Multi-Target Regression method and the Random Forest paradigm.•The proposed method ensures better performance in air quality forecast.
The paper is aimed at a class of fractional-slot permanent magnet- synchronous machines (FSPMSMs) equipped with phases made up of one coil parallel branches, with emphasis on their potential to ...reject the circulating harmonic currents. Following the identification and topological characterization of this class of machines treated in Part 1, the star of slots approach is extended to the investigation of their back-EMF harmonic content, and the possible resulting circulating harmonic currents. It is found that all identified candidates exhibit the potential to reject the circulating harmonic currents. A case study dedicated to a candidate equipped with three phases made up of six parallel branches of one coil each, is treated. Following an analysis of its back-EMF harmonic content, the torque-speed characteristic is analytically-predicted and validated by 2D finite element analysis and by experiments. The study is achieved by a special attention paid to the iron loss and thermal analysis.
•Three PGP bacteria were tested as bioelicitors for Pelargonium graveolens L'Hér growth.•Positive effects on growth parameters and photosynthetic pigments were observed.•Inoculation with P. ...rhizophila S211 + O. iheyensis E9 gave the highest leaf biomass.•The consortium was the most efficient to enhance phenolic and flavonoid production.•The dual inoculations are highly efficient to improve essential oils accumulation.
Pelargonium graveolens L'Hér. well known as rose-scented geranium is used worldwide in perfume, cosmetic, pharmaceutical and food industries. The essential oil and phenolic concentrations for this species were reported to be very low which requires their improvement. The effect of three plant growth promoting bacteria namely Pseudomonas rhizophila S211, Halomonas desertis G11 and Oceanobacillus iheyensis E9 on P. graveolens transplants were evaluated with single, dual and consortium modalities under semi controlled conditions. Significant positive effects on the growth related parameters, leaf and root biomass, photosynthetic pigments and secondary metabolites production were observed with inoculum-specific response. The highest root biomass was recorded with the dual inoculation H. desertis G11+ O. iheyensis E9 while the inoculum P. rhizophila S211 + O. iheyensis E9 showed the highest ability to enhance fresh leaf biomass (12.27 ± 0.61 g) leading to an improvement rate of 43.34 % over the control. A significant increase in the amounts of total phenolics and flavonoids contents in the inoculated plants over the control was revealed for all the treatments. The consortium was the most efficient to enhance the contents of total phenolics (105.62 ± 2.95 mg GAE/g DW) and flavonoids (48.55 ± 1.25 mg RE/g DW) resulting in an increase over the control of 67.35 % and 53.59 %, respectively. The essential oil synthesis was enhanced significantly for all the inoculated transplants compared with the control conditions. The dual inoculations resulted in the highest levels of essential oil contents in P. graveolens leaves, followed by the consortium than individual inoculants. The dual inoculation H. desertis G11 + O. iheyensis E9 gave the highest essential oil amount (0.49 ± 0.03 %) with an increase of 68.96 % over the control (0.29 ± 0.01 %). The GC–MS analyses of the essential oils resulted in the identification of 23 compounds. In all treatments, citronellol (25.84–40.02 %), geraniol (9.67–11.96 %), citronellyl formate (5.35–10.14 %), 2-phenylethyl tiglate (4.58–7.13 %), epi-γ-eudesmol (4.38–5.87 %) and linalool (2.56–4.07 %) are the main compounds with qualitative and quantitative variation. Interestingly, the three dual inoculations gave the highest amounts of citronellol, citronellyl formate and citronellyl tiglate compounds. The highest concentration of the high-value citronellol (40.02 %) which defines the commercial value of P. graveolens was recorded with the inoculum H. desertis G11+ O. iheyensis E9 resulting in an increase rate of 54.87 % over the control (25.84 %). This study suggests the efficiency of the studied inoculums as promising biofertilizers with significant potentials to enhance P. graveolens biomass and secondary metabolites production which present an alternative biotechnological tool to limit the excessive use of chemical fertilizers.
This work proposes an approach to design fractional-slot permanent magnet synchronous machines (FSPMSMs) equipped with phases made up of one coil parallel branches. These machines exhibit attractive ...potentialities, especially their enhanced open-circuit fault tolerance capability. Beyond their intrinsic fault tolerance, an open-circuit affecting the targeted topologies leads to a torque step-down limited to the one developed by the concerned coil rather than the torque produced by the total phase in FSPMSMs equipped with phases made up of series-connected coils. Furthermore, these topologies are suitably-adapted to low-voltage power supply that makes them viable candidates in automotive applications. This potentiality is by far vital in battery electric vehicles with the risk of electrocution in case of accident totally-eradicated thanks to the reduction of the DC bus voltage. Part 1 of the developed work is aimed at a star of slots-based identification and topological characterization of the FSPMSMs enabling the arrangement of the armature phases according to one coil parallel branches. The study distinguishes the topologies with odd and even number of phases, arranged in single- and double-layer slots. A case study is treated using a 2D finite element analysis and validated by experiments.
Purpose
The purpose of this paper is to analyze how monetary fundamentals affect exchange rate movements.
Design/methodology/approach
To develop this paper, a Bayesian Network modeling is applied to ...explore the causal interactions between monetary fundamentals and exchange rate fluctuations. Subsequently, a sensitivity analysis is performed to asses and estimate exchange rate behavior with uncertain monetary fundamentals. Furthermore, a Granger Causality test is used as suggested in the Econometric literature to determine the causality direction among factors.
Findings
The empirical findings show that money supply and interest rate have a significant positive effect on exchange rate, whereas inflation rate has a considerable negative effect on exchange rate. In addition, the authors deduce that real income has an indirect impact on exchange rate and a direct impact on inflation rate, interest rate and money supply. Furthermore, the sensitivity analysis shows that monetary uncertainty has a considerable effect on exchange rate fluctuations. Moreover, the Granger Causality test reveals that there is a unique unidirectional causality running from money supply to exchange rate.
Practical implications
The model can be considered as a vital management tool for international investors and financial analysts to explore the effect of monetary fundamentals on exchange rate behavior. It allows estimating exchange rate fluctuations with uncertain monetary factors.
Originality/value
This study is the first one which applied a Bayesian Network modeling to examine the exchange rate determination problem. Results of this research are presented under a clear graphical representation that can be easily useful by monetary policymakers and international traders to determine the influential monetary factors on exchange rate behavior. Also, the model will help them in estimating the effect of monetary uncertainty on exchange rate fluctuations.
In this work, a native exopolysaccharide (nEPS) produced by Halomonas desertis G11 isolated from a Tunisian extreme environment was modified by gamma irradiation. Characterization as well as the ...antioxidant and antitumor activities of nEPS and its gamma-irradiated derivatives (iEPSs) were comparatively evaluated. In vitro and in vivo antioxidant potentials were determined by using different methods and through different antioxidant enzymes. The antitumor activity was checked against a human colon cancer cell line. Analyses of the complete genome sequence were carried out to identify genes implicated in the production of nEPS. Thus, the genomic biosynthesis pathway and the export mechanism of nEPS were proposed. Analyses of irradiation data showed that iEPSs acquired new functional groups, lower molecular weights, and gained significantly (p < 0.05) higher antioxidant and antitumor abilities compared with nEPS. These findings provide a basis for using iEPSs as novel pharmaceutical agents for human therapies.
La sexualité est un aspect central de la personne humaine qui, devant des problèmes sexuels, va fréquemment se tourner vers une source qu'elle considère compétente et bien informée, son médecin. Les ...objectifs de notre étude étaient d’évaluer les connaissances, les attitudes et les pratiques des étudiants en médecine en termes de sexualité et d’identifier les principaux déterminants du manque de connaissances basiques à ce sujet. Notre étude était descriptive et analytique, menée auprès des étudiants à la faculté de médecine de Sfax (Tunisie). Le questionnaire, rempli individuellement et de manière anonyme par chaque étudiant, recueillait les données sociodémographiques, les connaissances en matière de sexualité ainsi que leurs sources, les attitudes adoptées par les étudiants vis-à-vis de la sexualité et les pratiques sexuelles. La note totale moyenne relative aux questions de sexologie était de 11,05/20. Les facteurs corrélés à un score moyen élevé aux questions de sexologie étaient le sexe masculin (p=0,003), le statut de marié (p=0,012), le niveau socio-économique élevé (p=0,02), les livres comme source d’informations (p=0,041) et la présence de pratiques sexuelles (p<0,001). Ces pratiques étaient toutes significativement plus fréquentes chez les étudiants de sexe masculin (p<0,001). Des lacunes dans les connaissances en matière de sexualité existent chez les étudiants en médecine, du moins dans certains de ses aspects. Un programme d'enseignement complet et uniforme sur la sexualité humaine, surtout dans ses aspects physiologiques, peut sensiblement améliorer la capacité des futurs médecins à fournir des soins optimaux à leurs patients.
Les phénomènes paroxystiques sont fréquents en période néonatale, notamment au cours de l’encéphalopathie anoxo-ischémique (EAI). La détermination de la nature épileptique de ses phénomènes est ...essentielle dans la prise en charge de l’EAI.
L’objectif de ce travail est d’étudier l’utilité de l’EEG dans l’analyse des phénomènes paroxystiques au cours de l’EAI et la détermination de leur nature épileptique.
Étude rétrospective colligeant 39 nouveaux-nés (NN) à terme admis pour prise en charge d’une EAI probable et ayant présenté des mouvements anormaux en période néonatale. Une analyse de la sémiologie clinique des phénomènes paroxystiques et des données d’un enregistrement électroencéphalographie vidéo (EEG-vidéo) ont été réalisés.
Le terme moyen était de 39,57±1,16 semaines d’aménorrhées avec un sexe ratio de 2,25. Les crises épileptiques, suspectées cliniquement, étaient séquentielles dans 66,7 % avec des automatismes chez 61,5 % des NN. L’EEG-vidéo a confirmé la nature épileptique de ces crises chez 12,8 % des NN tandis que les phénomènes paroxystiques non épileptiques, à type de trémulation, ont été retrouvés chez 23,10 % des NN. Des crises électrographiques seules sans manifestations cliniques ont été observées chez 7,7 % des NN.
L’écart observé entre les crises décrites cliniquement et les crises confirmées par l’EEG peut être expliqué par le sur-diagnostic clinique des crises épileptiques mais aussi par l’utilisation d’enregistrement EEG-vidéo non prolongé dans le temps réduisant la probabilité de capter des crises électro-cliniques.
Dans le contexte d’EAI, l’EEG-vidéo, a un rôle essentiel dans le diagnostic des crises épileptiques par distinction entre les manifestations épileptiques et non épileptiques et dans le diagnostic des crises électrographiques seules.
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