The effect of oil price shocks on the Saudi manufacturing sector

This paper aims to examine the effects of oil price shocks on the manufacturing sector in Saudi Arabia during the period 2002 – 2014, using quarterly data. A unit root test was conducted, in which the data were shown to be non-stationary in the level, and they became stationary in the first difference for all variables. The co-integration model was applied, and the results indicated that no co-integrating equation exists, which means that there is no long run effect of oil price shocks on the manufacturing sector. So, we estimate a Vector Auto Regressive model, the results of which implied that oil price shocks do not affect in the manufacturing sector in the short run, and it may have an effect on the manufacturing sector after 10 quarter according to the impulse response function

14-Bromo-12-chloro-2,16-dioxapentacyclohenicosa-3(8),10,12,14-tetraene-7,20-dione

In the title compound, C19H16BrClO4, both the fused xanthene rings and one of the cyclohexane rings adopt envelope conformations, while the other cyclohexane ring is in a chair conformation. In the crystal, molecules are linked by C-H...O hydrogen bonds, forming infinite chains running along [10-1] incorporating R22(16) ring motifs. In addition, C-H...[pi] interactions and weak [pi]-[pi] stacking interactions [centroid-centroid distance = 3.768 (3) Å] help to consolidate the packing

Hydrodynamic drag-force measurement and slip length on microstructured surfaces

International audienceIn this paper, a drainage experiment of water between a borosilicate sphere and a microstructured surface constituted by regularly spaced pillars is presented. The microstructured surface has two parts: on one part the liquid forms a Cassie interface and on the second it forms a Wenzel interface. The measured hydrodynamic drag force is larger on the Cassie part compared to the Wenzel part. Furthermore, for the Cassie part, from the hydrodynamic drag force measurements on a pillar and between pillars the corresponding local slip lengths have been extracted. The area average slip length on the surface is in agreement with the value expected by Philip's equation

Egg-associated Salmonella enterica serovar Enteritidis: comparative genomics unveils phylogenetic links, virulence potential, and antimicrobial resistance traits

Salmonella enterica serovar Enteritidis (SE) remains a frequent cause of foodborne illnesses associated with the consumption of contaminated hen eggs. Such a food–pathogen association has been demonstrated epidemiologically, but the molecular basis for this association has not been explored. Comparative genomic analysis was implemented to decipher the phylogenomic characteristics, antimicrobial resistance, and virulence potential of eggs-associated SE. Analyzing 1,002 genomes belonging to 841 sequence types of food-isolated SE strains suggests a high genomic similarity within the egg-related lineage, which is phylogenetically close to SE strains isolated from poultry but is different from those isolated from beef. Core genome- and single nucleotide polymorphism (SNP)-based phylogeny of 74 SE strains of egg origin showcased two distinct sublineages. Time-scaled phylogeny supported the possibility of a common ancestor of egg-related SE lineages. Additionally, genome mining revealed frequent antibiotic resistance due to the presence of aac(6’)-Iaa and mdsAB encoded on the genomes of egg-associated SE strains. For virulence gene profiling, 103–113 virulence determinants were identified in the egg-associated SE, which were comparable to 112 determinants found in human-associated SE, emphasizing the capacity of egg-associated strains to infect humans and cause diseases. The findings of this study proved the genomic similarity of egg-associated SE strains, and these were closely related to poultry strains. The egg-associated strains also harbor virulence genes equivalent to those found in human-associated SE strains. The analysis provided critical insights into the genetic structure, phylogenomics, dynamics of virulence, and antibiotic resistance of Salmonella Enteritidis, circulating in eggs and emphasizing the necessity of implementing anti-Salmonella intervention strategies, starting at the production stage of the poultry supply chain

Untargeted metabolomics unveiled the role of butanoate metabolism in the development of Pseudomonas aeruginosa hypoxic biofilm

Pseudomonas aeruginosa is a versatile opportunistic pathogen which causes a variety of acute and chronic human infections, some of which are associated with the biofilm phenotype of the pathogen. We hypothesize that defining the intracellular metabolome of biofilm cells, compared to that of planktonic cells, will elucidate the metabolic pathways and biomarkers indicative of biofilm inception. Disc-shaped stainless-steel coupons (12.7 mm diameter) were employed as a surface for static biofilm establishment. Each disc was immersed in a well, of a 24-well microtiter plate, containing a 1-mL Lysogeny broth (LB) suspension of P. aeruginosa ATCC 9027, a strain known for its biofilm prolificacy. This setup underwent oxygen-depleted incubation at 37°C for 24 hours to yield hypoxic biofilms and the co-existing static planktonic cells. In parallel, another planktonic phenotype of ATCC 9027 was produced in LB under shaking (200 rpm) incubation at 37°C for 24 hours. Planktonic and biofilm cells were harvested, and the intracellular metabolites were subjected to global untargeted metabolomic analysis using LC-MS technology, where small metabolites (below 1.5 kDa) were selected. Data analysis showed the presence of 324 metabolites that differed (p < 0.05) in abundance between planktonic and biofilm cells, whereas 70 metabolites did not vary between these phenotypes (p > 0.05). Correlation, principal components, and partial least square discriminant analyses proved that the biofilm metabolome is distinctly clustered away from that of the two planktonic phenotypes. Based on the functional enrichment analysis, arginine and proline metabolism were enriched in planktonic cells, but butanoate metabolism was enriched in biofilm cells. Key differential metabolites within the butanoate pathway included acetoacetate, 2,3-butandiol, diacetyl, and acetoin, which were highly upregulated in the biofilm compared to the planktonic cells. Exogenous supplementation of acetoin (2 mM), a critical metabolite in butanoate metabolism, augmented biofilm mass, increased the structural integrity and thickness of the biofilm, and maintained the intracellular redox potential by balancing NADH/NAD+ ratio. In conclusion, P. aeruginosa hypoxic biofilm has a specialized metabolic landscape, and butanoate pathway is a metabolic preference and possibly required for promoting planktonic cells to the biofilm state. The butanoate pathway metabolites, particularly acetoin, could serve as markers for biofilm development

Combustion contribution to noise in jet engines

The relative importance of combustion as a source of noise in a flow regime representative of a subsonic jet engine exhaust was investigated. The combustion noise source characteristics were obtained from pressure and temperature fluctuation measurements in the combustor and exhaust nozzle. The similarity between the fluctuations in this source region and the far field noise were compared. In the jet exhaust velocity range between 450 and 660 ft/sec investigated in detail, the frequencies of dominant pressure and temperature fluctuations in the combustor were also the frequencies of the dominant far field noise. The overall noise levels were 14 to 20 dB higher than from a corresponding clean jet in the same velocity range. Thus it seemed clear that the unsteadiness associated with the combustion process was responsible for the dominant noise in the far field. A simple analysis to predict the far field noise due to the internal pressure fluctuations causing exit plane velocity fluctuations produced trends closely resembling the measured results, but under predicted the far field noise over the spectral range examined. The possible reason for the higher far field noise is direct transmission of acoustic waves through the nozzle, which was not accounted for in the prediction scheme

Some Heavy Metals Status in Ashtoum El-Gamil Protected Area

ABSTRACT A survey study was conducted on some heavy metals (Pb, Cd, Cu, Zn, and Fe) in water, sediment, and fish samples from Ashtoum El-Gamil protected area during May 2010 to January 2011. Data obtained revealed that there were significant (P≤0.0001) differences among sampling seasons and stations as well as their interactions concerning the levels of heavy metals tested in either water, sediment, or fish collected from this protected area. The elements level took the descending order Zn ≥ Cd ≥ Pb ≥ Fe ≥ Cu in the water, Pb ≥ Fe ≥ Cu ≥ Zn ≥ Cd in the sediment, and Fe ≥ Pb ≥ Zn ≥ Cu ≥ Cd in the fish body samples. Proximate analysis of the tested fish (mullet and tilapia) reflected also significant (P≤0.0001) effects due to sampling seasons and stations and their interactions besides fish species. Some significant correlations were calculated among heavy metals (in water, sediments, and fish) and chemical composition of the fish

7-Bromo-9-(2-hy­droxy-4,4-dimethyl-6-oxocyclo­hex-1-en-1-yl)-3,3-dimethyl-2,3,4,9-tetra­hydro-1H-xanthen-1-one

In the xanthene ring system of the title compound, C23H25BrO4, the 4H-pyran ring is almost planar [maximum deviation = 0.040 (3) Å] and the cyclo­hexene ring adopts a sofa conformation. The cyclo­hexene ring attached to the xanthene system is puckered [Q T = 0.427 (3) Å, θ = 55.0 (4) ° and ϕ = 164.4 (6) °]. In the crystal, mol­ecules are linked to each other by O—H⋯O and C—H⋯O hydrogen bonds

An Adaptive Protection Scheme Based on a Modified Heap-Based Optimizer for Distance and Directional Overcurrent Relays Coordination in Distribution Systems

This paper proposes an adaptive protection scheme (APS) based on the original heap-based optimization (HBO) and a modified HBO (MHBO). APS is used to solve protection relays coordination problems that include directional overcurrent relays (DOCRs) as well as the distance relay’s second zone times. The complexity of the coordination problem increases with the impact of distributed generators (DGs) switching (ON/OFF). Topological changes in grid configuration frequently occur in distributing networks, equipped with DGs, causing changes in the values and direction of short circuit currents. This issue becomes a challenge for protection systems to avoid relays miscoordination and save a network’s reliability. In the proposed MHBO, the Original HBO is modified by three points, population are divided into subgroups, then they are unified into one group gradually, those subgroups are exchanging some search agents between themselves, these search agents are called travelling agents, and the last one is about, upgrading an internal equation in the original algorithm. For validating the proposed relays coordination, the IEEE 8-bus test system, and the IEEE 14-bus distribution network are selected as case studies. The obtained simulated results of the proposed algorithm show better performance compared with those obtained by the previous algorithms. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This work was funded by the Deanship of Scientific Research at Jouf University under grant No (DSR-2021-02-0306)

Vector Control of a Doubly-Fed Induction Generator by Using a Classical PI and a fuzzy PI Controllers

This work deals with the conversion of wind systems in order to improve the quality of the provided energy. To this end, we are interested in the modeling and the simulation of a Doubly-Fed Induction Generator (DFIG) with a wound rotor used in the electromechanical conversion of wind systems. In this paper, we carried out the modeling and the direct and indirect vector control of the (DFIG) by using a classical PI controller and then a fuzzy logic PI controller. The aim of these control systems is to minimize the interaction between active and reactive power and to ensure an efficient decoupling by the use of two algorithms: fuzzy logic control and classical control.nbsp The algorithms are developed and tested under Matlab/Simulink