The current study is the first phylogenetic and secondary RNA structure analysis of Dactylogyrus species parasitising gill filaments of Iraqi cyprinid fishes. Most previous phylogenetic studies have targeted on primary DNA sequence data. Nevertheless, RNA secondary configuration is principally helpful in systematics since they comprise features that do not appear in the primary sequence and provide morphological information. The primary objective was molecular-based identification of Dactylogyrids species using evolutionary tree and secondary RNA structure prediction. A total of 681 fish were collected from the Lesser Zab River in the northeast of Iraq in the sub-district of Altun-Kopru from August 2016 to September 2017 and brought to the Zoology Research Laboratory, Salahaddin University-Erbil, Iraq. All fish were classified as 18 cyprinid species. The species of Dactylogyrus were identified by the 28S rDNA subunit using PCR and sequencing methods, and the obtained nucleotide sequences were then compared with the available GenBank sequences. Phylogenetic relationships were concluded using Neighbour-Joining (NJ), Maximum Likelihood (ML), and Minimum Evolution (ME) methods. The results justify the validation of 11 Dactylogyrus species (three of them were newly recorded in Iraq). Additionally, out of nine infected fish species, seven of them were regarded as a new host for Dactylogyrus species. Secondary RNA configuration prediction using minimum free energy was considered as a hopeful tool for species identification. This was considered the first comprehensive phylogenetic study in the area. It was concluded that PCR sequencing, phylogenetic and secondary RNA analysis were proper molecular methods for identifying Dactylogyrids species on the gills of fishes.
One of the applications of tether system is in the field of satellite technology, where the mother ship and satellite equipment are connected with a cable. In order to grasp the motion of this kind of tether system in detail, the tether can be effectively modeled as flexible body and dealt by multibody dynamic analysis. In the analysis and modeling of flexible body of tether, large deformation and large displacement must be considered. Multibody dynamic analysis such as Absolute Nodal Coordinate Formulation with an introduction of the effect of damping force formulation can be used to describe the motion behavior of a flexible body. In this study, a parameter identification technique via an experimental approach is proposed in order to verify the modeling method. An example of swing-up control using the genetic algorithm control approach is performed through simulation and experiment. The validity of the model and availability of motion control based on multibody dynamics analysis are shown by comparison between numerical simulation and experiment.
Most of the formulations regarding the characteristics of a shell and tube heat exchanger have a common assumption; namely that the baffle plates are equidistant. This assumption fails to cater the real world scenario for defective baffles as the alteration in a shell and tube heat exchanger invalidates the equidistant baffle spacing of the plates. In this regard, a small six baffles heat exchanger was modeled in the computational fluid dynamics software package and studied by removing each baffle plate one at a time. Effect of removing each baffle plate on the temperature, pressure, heat transfer coefficient, and total heat transfer rate was recorded. It was observed that variation in the pressure drop for the same number of baffle plates varies along the axial order of the plates. The change in pressure drop due to the removal of the baffle plate near the inlet and the outlet was lowest and reaches a maximum in the axial center. It was also found that the plates below the radial center contribute higher towards the overall heat transfer as compared to those above.
There is a growing body of research investigating the relationships among gratitude, self-esteem, and subjective well-being. However, there remains a scarcity of research examining the impact of self-esteem on the relationship between gratitude and subjective well-being within Arabic context. In this study, 300 Arabic speaking adults completed measurements of gratitude, self-esteem, satisfaction with life, and positive and negative experiences. Participants’ ages ranged between 18 and 54 years with a mean age of 29.67 years (SD = 8.91). The correlation results revealed that there were significant positive relationships between gratitude, self-esteem, satisfaction with life, and positive experience, while there were significant negative relationships between gratitude, self-esteem, satisfaction with life, and negative experience. The results also showed that gratitude and self-esteem directly predicted subjective well-being. Additionally, using structural equation modeling, self-esteem exerted a mediation effect on the relationship between gratitude and subjective well-being. The results suggest that enhancing self-esteem could assist adults who have gratitude to experience greater subjective well-being. Using the source of self-esteem, researchers and professionals could improve one’s subjective wellbeing by employing various gratitude activities.
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