Selfishness in secure internet of things networks: 6TiSCH case study

Wireless Networks - Performance and communication security in the Internet of Things (IoT) area draw a major concern for both academic and industrial communities. Indeed, an emerging number of IoT...     

Detection of methicillin-resistant coagulase-negative staphylococci and PVL/mecA genes in cefoxitin-susceptible Staphylococcus aureus (t044/ST80) from unpasteurized milk sold in stores in Djelfa,Algeria

This study was designed to determine antimicrobial resistance phenotypes and genotypes and virulence factors in Staphylococcus aureus and coagulase-negative staphylococci (CNS) in unpasteurized milk sold in Djelfa, Algeria. Eighty-two unpasteurized cow milk samples were randomly obtained from 82 retail stores in Djelfa and tested to detect staphylococci. Species were identified by biochemical tests and MALDI-TOF. Antimicrobial resistance phenotypes and genotypes were determined by disk diffusion test, PCR, and sequencing. The Staph. aureus isolates were subjected to spa typing, multilocus sequence typing, and detection of virulence genes and the scn gene by PCR and sequencing. Forty-five (54.9%) milk samples were contaminated by staphylococci and 45 isolates were recovered: 10 Staph. aureus (12.2% of total samples) and 35 CNS (42.7%). Resistance to penicillin (blaZ), tetracycline (tetL/tetK), and erythromycin (ermB/msrA/ermC) were the most common phenotypes (genotypes). Three CNS were methicillin-resistant and all were mecA-positive. The Staph. aureus isolates were ascribed to the following lineages [spa type/sequence type/associated clonal complex (number of isolates)]: t267/ST479/CC479 (n = 6), t1510/ST5651/CC45 (n = 1), t359/ST97/CC97/ (n = 1), t346/ST15/CC15 (n = 1), and t044/ST80 (n = 1). The mecA gene was detected in the cefoxitin-susceptible t044/ST80 isolate and co-harbored the lukF/lukS-PV and scn genes. The detection of mecA-PVL-positive Staph. aureus, methicillin-resistant CNS, and multidrug-resistant staphylococcal species indicates a potentially serious health issue and reveals that unpasteurized milk sold in Djelfa city could be a potential vehicle for pathogenic and antimicrobial-resistant staphylococci.     

Treated municipal wastewater as option to the use of fresh water for the cultivation of valuable pastoral species Buffel grass (Cenchrus ciliaris L.)

The increasing aridity exacerbated by climatic changes is leading to loss of perennial herbaceous plants Cenchrus ciliaris, an apomictic, polyploid grass used as forage in hot and dry areas, and is currently under threat for the increased scarcity of water. In this study, treated municipal wastewater (TWW) was used to irrigate two ploidy levels of C. ciliaris for two consecutive years. The objectives were (1) to assess the possibility of using unconventional water for watering C. ciliaris and (2) to identify at what extent TWW irrigation affected growth and nutritive properties of C. ciliaris that differed for polyploidy level. TWW irrigation positively affected growth and physiological plant parameters. In leaves of TWW watered C. ciliaris, the concentration of N_t, P and K significantly increased. The tetraploid C. ciliaris showed a better growth and quality than the hexaploid ones, appearing the most suitable cultivar to be irrigated with TWW for feed uses. In short, TWW can be strategically used for irrigating forage species with the double output of ameliorating soil properties, recovering degraded area and improving the nutritive values of fodder species contributing to the promotion of a green and sustainable circular economy, more in climatically under pressure developing countries.     

Study of C.I. Reactive Yellow 145, C.I. Reactive Red 238, and C.I. Reactive Blue 235 dyestuffs in order to use them in color formulation. Part 1: characterization and compatibility

Generally, textile dyeing is based on a mixture of several dyestuffs used in different proportions to achieve the desired-colors. The dyes used in a mixture should react with the fiber similarly; thus they must be compatible among themselves. So, to realize mixtures it is indispensable to study the compatibility of dyes, in order to ensure optimal dyeing formulation. This paper describes the characterization and studies the compatibility of three cold bifunctionnal reactive dyes (C.I. Reactive Yellow 145, C.I. Reactive Red 238, and C.I. Reactive Blue 235) in order to explore the possibility to use them in mixtures. The dye compatibility was studied based on several criteria such as dye extinction coefficients, exhaustion and fixation yield rates, adsorption kinetics, and adsorption isotherms. The exhaustion and fixation yield rates of all three dyes was compared between them and their adsorption kinetics and adsorption isotherms models were drawn and discussed. Between the different studied models, the Elovich model presents the best model describing the kinetics of different dyes, and Freundlich model presents the best model for analyzing the adsorption isotherms. The obtained results show that the analyzed dyes are perfectly compatible and have the same dyeing properties. They present close extinction coefficients as well as similar exhaustion and fixation yield rates.     

Purely accelerating and decelerating flows within two flat disks

Summary This paper deals with the power series solutions of the steady, laminar, radial flows either purely accelerating, or purely decelerating, that develop in the gap formed by two flat disks. The results include velocity profiles and static pressure distributions. These are compared with previously reported approximate solutions or the experimental data for the pressure obtained by others. The development of the two types of flows is shown to be entirely different except for (parameter that combines the non-dimensional radial distance and Reynolds number) close to zero where both behave as Poiseuille's flows between two infinite plates. For the inflow, the radial velocity flattens near the mid-plane diffusing towards the walls as the parameter increases. In contrast to the inflow, the magnitude of the maximum velocity of the outflow is shown to increase with , indicating that most of the fluid motion is taking place near the central channel region. For the outflow, two critical values of are used to indicate notable flow field transformations. The first marks the point where the pressure difference changes sign, while the second denotes when the derivative of the velocity (in the axial direction) on the wall becomes zero. Beyond the second value, purely decelerating flow cannot exist. The sign change of the pressure is attributed to the interaction between the inertia, viscous, and pressure forces.     

Synthetic Co-Attractants of the Aggregation Pheromone of the Date Palm Root Borer <Emphasis Type="Italic">Oryctes agamemnon</Emphasis>

Laboratory and field investigations to identify and evaluate plant co-attractants of the aggregation pheromone of the date palm pest Oryctes agamemnon are reported. Volatiles emitted by freshly cut palm core and palm core with feeding males, were collected, analyzed by gas chromatography coupled to mass spectrometry and evaluated in olfactometers alone or combined with synthetic pheromone. A collection of palm odor without male effluvia was attractive alone and enhanced attraction to synthetic pheromone in an olfactometer similar to that to a collection of palm odor emitted with feeding males and containing natural pheromone. Behavioral responses to collections of palm volatiles were correlated to the amount of volatiles material in them. Enhancement of the attractiveness of the pheromone was not correlated to chemicals specific to beetle feeding. The chemicals common to the active collections extracts were benzoate esters, mostly ethyl benzoate, anisole derivatives and sesquiterpenes. Blends of the most abundant components of the extracts were evaluated for enhancement of the attractiveness of pheromone (1 μg) in olfactometers at 1 or 10 μg doses. The mixtures were further evaluated by field trapping in Tunisia at 3–10 mg/day using reference (6 mg/day) or experimental pheromone formulations. A mixture of ethyl benzoate, 4-methylanisole and farnesol (1:1:1 w/w at 6.5 mg/day) enhanced captures in pheromone baited traps in 2014 and 2015 and this mixture was as active as the natural palm bait. The practical prospect of the result for the management for O. agamemnon, and other palm beetles is discussed.     

The power manipulability – A new homogeneous performance index of robot manipulators

Jacobian-based performance indices such as the manipulability ellipsoid, the condition number and the minimum singular value, have been very helpful tools both for mechanical manipulator design and for determining suitable manipulator postures to execute a given task. For a manipulator having complex degrees of freedom (translations and rotations), Jacobian matrix becomes non-homogeneous, i.e. it contains elements with different physical units; therefore, the evaluation of its determinant, eigenvalues or singular values needs the combination of quantities of different nature, which is physically inconsistent and moreover it corresponds to a noncommensurable system. In this paper, a new performance index of robot manipulators is proposed. It is fully homogeneous and it constitutes a physically consistent system whether the manipulator contains joints of different natures, or the task space combines both translation and rotation motion. The development is concerned with the study of power within the mechanism. Given that the power has the same physical units in translation and rotation, it can be used as a homogeneous or natural performance index of manipulators by examining the behaviour of its basic components namely, force and speed, at different kinematics configurations. Furthermore, the new concept of vectorial power is introduced, followed by to the quadrivector of apparent power, and leading to the final homogeneous performance index of the power manipulability (PM). This new approach matches perfectly with mechanisms having joints of different natures, as well as with a task space combining both translation and rotation.     

Dietary exposure of Tunisian adult population aged from 19 to 65 years old to pesticides residues

ABSTRACT

Dietary exposure of the Tunisian adult population to pesticide residue was assessed using the Total Diet Study method. In the present study 170 pesticides were searched for in 42 aggregated foods characterised by 64 food samples representing the Tunisian diet. All the food samples were collected, prepared, and analysed for remains of pesticides including organochlorine, organophosphorous, carbamates and pyrethroids. The GC-MS analysis and the LC-MS/MS analysis and some other specific analytical methods were employed for the quantification of the pesticide residues in the food samples. Results revealed that21pesticides reached amounts greater than the LOQ(12.3%) and 149 pesticides reached amounts below the LOD (88%).For the 21 pesticides quantified, the ADI was not exceeded. For the 149 non-quantified pesticides, an interval defined by the lower and upper bounds was defined to assess the dietary exposure of the Tunisian adult population to those pesticides. We conclude that 8 pesticides theoretically exceed the ADI with the 95^th percentile of exposure, those are: Diféthialone, Brodifacoum, Bromadiolone, Glufosinate, Heptachlor, Dieldrin Aldrin Oxydemeton-methyl. This study concludes that there is a low dietary exposure to pesticide residue of the Tunisian adult population. In fact, all the cases where the ADI was exceeded were theoretical due to the lower ADI value used.     

Efficiency investigation of a new-design air solar plate collector used in a humidification–dehumidification desalination process

The aim of this research is to experimentally study the efficiency of a new-design plate collector used to heat air in a new desalination humidification–dehumidification process. In fact, in such processes, the air solar collectors work at unusual experimental parameters (forced convection, elevated air humidity, high solar irradiation…). At these stressed experimental conditions, few published works are available in literature. Furthermore, the comparison of the efficiency of collectors running with normal air humidity content (about 10–20 g kg⁻¹) and air of elevated humidity (20–50 g kg⁻¹) were not yet published as our knowledge. In the present investigation, a new air solar plate collector was designed and developed for its use in a desalination process. Moreover, a characterization of such collector was performed under different experimental conditions. The effect of different parameters, namely: the solar radiation, the wind velocity, the ambient temperature, the air mass flow rate, the inlet air humidity and temperature, on the collector efficiency was also investigated. The collector was optimized for its use in a new solar desalination process. In fact, the air solar collector was designed in order to lower its economic cost making them applicable for water desalination.