This work aims to analyze a three-dimensional discrete-time biological system, a prey-predator model with a constant harvesting amount. The stage structure lies in the predator species. This analysis is done by finding all possible equilibria and investigating their stability. In order to get an optimal harvesting strategy, we suppose that harvesting is to be a non-constant rate. Finally, numerical simulations are given to confirm the outcome of mathematical analysis.

The nanocrystalline porous silicon (PS) films are prepared by electrochemical etching ECE of p -type silicon wafer with current density (10mA/cm ) and etching times on the formation nano -sized pore array with a dimension of around different etching time (10 and 20) min. The films were characterized by the measurement of XRD, atomic force microscopy properties (AFM). We have estimated crystallites size from X -Ray diffraction about nanoscale for PS and AFM confirms the nanometric size Chemical fictionalization during the electrochemical etching show on the surface chemical composition of PS. The atomic force microscopy investigation shows the rough silicon surface, with increasing etching process (current density and etching time) porous st

          The present paper studies the generalized Φ-  recurrent of Kenmotsu type manifolds. This is done to determine the components of the covariant derivative of the Riemannian curvature tensor. Moreover, the conditions which make Kenmotsu type manifolds to be locally symmetric or generalized Φ- recurrent have been established. It is also concluded that the locally symmetric of Kenmotsu type manifolds are generalized recurrent under suitable condition and vice versa. Furthermore, the study establishes the relationship between the Einstein manifolds and locally symmetric of Kenmotsu type manifolds.

The effects of gamma irradiation on the structure of ZnS films , which preparing by flash evaporation method, are studied using XRD. Two peaks of (111), (220) orientations are appeared in X ray chart indicating the cubic phase of the films .The lattice parameter, grain size, average internal stress, microstrain, dislocation density and degree of preferred orientation in the film are calculated and correlated with gamma irradiation.

    The plant Abrus precatorius, which belong to Leguminosae (Fabaceae) family and known as Crab’s eyes, Rosary pea with characteristic red and black seeds. It was used in folk medicine in India, China and East Asian countries for treatment of various diseases.    The plant was extracted by '' general method of extraction'' (Harborne, 1973) using 80% aqueous ethanol as a solvent of extraction by soxhlet apparatus. Preliminary qualitative phytochemical screening were performed on the crude ethanolic extract  and revealed the presence of alkaloids, flavonoids ,terpenoids and phytosterols in Iraqi Abrus precatorius plant. Three different fractions were obtained from crude extract which are fraction one (chloroform fractio

With the exception of Antarctica, all continents are home to Echinococcus species. These parasite infections are thought to be quite dangerous, causing high rates of morbidity and mortality as well as large financial losses for the cattle sector from a human and veterinary standpoint, the two primary species to consider are Echinococcus granulosus sensu lato (s.l.) and Echinococcus multilocularis, which cause cystic echinococcosis (CE) and alveolar echinococcosis (AE), respectively. The present state-of-the-art knowledge on these two parasites is compiled in this study in four major areas that are pertinent to both human and veterinary professionals: diagnosis, treatment and prevention, clinical symptoms and pathogenesis, and transm

In the present study, new five polymers of acryloyl chloride have been synthesized by reaction 4-aminoantipyrine with many substituted acid chloride (A-E). Then condensation of polyacryloyl chloride with the product in one step (A-E), in a suitable solvent in the presence amount of (Et3N) to obtain new polyimides(A1-E5). The prepared compounds were characterized by UV. FT-IR, 1H-NMR and 13C-NMR spectroscopy and measuring of other physical properties such as softening point, melting point and solublities.

Objectives: To assess the psychological adjustment of middle school students and to identify the relationship between differences in demographic characteristics and psychological adjustment.

Methodology: A descriptive correlation design was used. The study utilized a simple random sample to select (381) students using self-report to select students who will be recruited into the study for the period from November 26^th, 2021 to April 1^st, 2022. A scale approved in the study consisting of 40 items was chosen. It measures four trends which are personal, social, familial, and emotional adjustment. The data were analyzed by applying the descriptive statistical dat