We focus on studying the dynamics of bulk semiconductor optical amplifiers and their effects on the saturation region for short pulse that differ, however there is the same unsaturated gain for both dynamics. Parameters like current injection, fast dynamics present by carrier heating (CH), and spectra hole burning (SHB) are studied for regions that occur a response to certain dynamics. The behavior of the saturation region is found to be responsible for phenomena such as recovery time and chirp for the pulse under study.
In this paper, an ecological model with stage-structure in prey population, fear, anti-predator and harvesting are suggested. Lotka-Volterra and Holling type II functional responses have been assumed to describe the feeding processes . The local and global stability of steady points of this model are established. Finally, the global dynamics are studied numerically to investigate the influence of the parameters on the solutions of the system, especially the effect of fear and anti-predation.
Man has a great role in the development of society in all fields, and therefore the human thought played a great role in its continuous pursuit and insight into the social classes that differ in their privileges, which makes the members of society not reconcile because of that disparity that is not based on human principles, so one class exploits another, and this is what stopped me Rather, it prompted me to choose the topic (class and its impact on society) in order to show the impact of classes on each other negatively and positively, so I work to avoid the first with the recommendations I put forward and offer guidance, and strengthen the second, and after this topic of necessity in a place because of the imbalance and promise of appr
... Show Moreيهدف البحث الحالي الى استكشاف علاقات التفاعل والتاثير بين الاحتكام للمكانة والتوجه للفردية– الجماعية والدمج التنظيمي مستنداً على مزج اختلاف القيم الشخصية مع افكار نظرية الهوية الاجتماعية لبلورة نموذج البحث. وفي ضوء هذا تم صياغة عدد من الفرضيات التي توضح علاقات التفاعل ما بين ابعاد الاحتكام للمكانة والتوجه للفردية– الجماعية للتنبؤ بوجود الدمج التنظيمي. جمعت البيانات باستخدام استمارة الاستبيان ووزع
... Show MoreThe aim of the present study is to investigate whether or not xanthine oxidase (XO)–derived reactive oxygen species (ROS) may play a role in the pathogenesis of alloxan (ALX)–induced diabetes in rats using the specific XO inhibitor and hydroxyl radical scavenger, allopurinol
The involvement of oxidative stress in ALX – diabetes was assessed by the measurement of plasma and various tissues lipid peroxides levels ( using thiobarbituric acid ( TBA ) reactive substances ). Furthermore, the ability of allopurinol to influence these and other biochemical parameters, including plasma and urine ketones levels were also investigated in diabetic rats.
Rats were divided into four groups: control, untreated diabe
... Show MoreAdditive aluminum powder to the polystyrene to prepare the composites Polystyrene– Aluminum.The samples were prepared by using mechanical compressed method at low pressure and a temperature 120°C. Measurements of absorbance and reflectance spectra were carried out by UV-Visible spectrophotometer , the effect of additive aluminum on the optical band gap Eop and optical constants ( refractive index n, extinction coefficient k ,dielectric constant ε and optical conductivity σop) were studied for the prepared composites . Results showed a decrease in the Eop with increasing perc
... Show MoreFive representative sampling stations were selected in upper region of Euphrates river. Bimonthly sampling were collected from December 2000 to December 2001. Rotifera showed high density in December 2000 while high density of cladocera which recorded in October .The results of relative abundance index showed that rotifera: Polyarthera dolichoptera , Keratella cochlearis , K. valga, Cephalodella auriculata and cladocera: Bosmina longirostris , B.coregoni ,Chydorus spharicus, were more abundant in study stations. The results of constancy index showed 4 taxa belonged to rotifera and 2 taxa belonged to cladocera which were considered constant in the Euphrates river, where the other species varied between accessory and accidental speci
... Show MoreThe Tamarix aphylla is a wild perennial shrub with erect stems that are long and glabrous. They have leaves that are simple, alternate, sheathed, and the apex of the blade is acuminate. And a scaly clawed bract and the the inflorescences were simple, spike-like. The pistil consists of ovary pyramidal, 3 styles, and 3 stigmas. The androecium consists of five stamens that are antisepalous. The perianth was distinct with five sepals and five petals. The fruits were capsule-shaped, pyramidal, and smooth. The seed has an apical pappus of unicellular hygroscopic hairs; endosperm is absent. The anatomical study of the leaves contained a uniseriate epidermis consisting of one layer of elongated cells covered by a layer of papillary cuti
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