In this paper the queuing system (M/Er/1/N) has been considered in equilibrium. The method of stages introduced by Erlang has been used. The system of equations which governs the equilibrium probabilities of various stages has been given. For general N the probability of j stages of service are left in the system, has been introduced. And the probability for the empty system has been calculated in the explicit form.

Let G be a graph, each edge e of which is given a weight w(e). The shortest path problem is a path of minimum weight connecting two specified vertices a and b, and from it we have a pre-topology. Furthermore, we study the restriction and separators in pre-topology generated by the shortest path problems. Finally, we study the rate of liaison in pre-topology between two subgraphs. It is formally shown that the new distance measure is a metric

The study includes the relationship between the ecologia and Abbaside's community in the middle ages, and the role of Baghdad capital city to increasing the sensibility of the people to the outwardly peripheral.

The study explains the efforts between the people and Abbaside's government to cure the knowledge of ecologia, to prevent the separation of diseases and  pollutions of the community. 

 Keywords: Ecologia, Abbasid's, diseases, pollutions.

     A Spectroscopic study has been focused in this article to study one of the main types of active galaxies which are quasars, and to be more precise this research focuses on studying the correlation between the main engine of Quasi-Stellar Objects (QSO), the central black hole mass (SMBH) and other physical properties (e.g. the star formation rate (SFR)). Twelve objects have been randomly selected for “The Half Million Quasars (HMQ) Catalogue” published in 2015 and the data collected from Salon Digital Sky survey (SDSS) Dr. 16. The redshift range of these galaxies were between (0.05 – 0.17). The results show a clear linear proportionality between the SMBH and the SFR, as well as direct proportional between the luminosit

Measuring university teachers attitudes towards the security man Summary This research aims to study the measurement of university teachers attitudes towards the security man, and represented the research sample (196) of teachers, including 124 males and 72 females from different faculties of Salah al-Din - Erbil University. The researchers adopted on a scale (Al-Tarawneh 2008), as amended, and its development, the scale consists of four areas and (28) paragraph covers paragraphs measure the beliefs and feelings of the individual towards the security man as the theme of direction. The research sample answered all the paragraphs of the scale grade five similar styles (Likert) (strongly OK, OK, neutral, non-OK, Strongly Disagree). The rese

A study of the emission spectra of isotopic for electronic states has been carried out. The energies of the vibration levels ( =0,1,..25) and the values of spectral lines R(J) and P(J) versus rotational quantum number (J=0,1..25). It was found that were an increase of the value of R(J) with the increase of the values of J was found while the value of P(J) decreases with decreasing of the values of J . It was found that corresponding to R(J) and P(J) the spectral line R(J) increases when the values of m increased.

This study deals with The Millstone (1965) which is a dramatic depiction of a single
mother heroine in a classic predicament. This novel is considered as representative of the age
in which it was written. The primary theme is her intense preoccupation with questions of
fatalism and will. The work also involves, both explicitly and implicitly, feminist concerns.
Because the central protagonist is a woman and the society in which she lives is depicted,
accurately, as deeply patriarchal and class-bound, the problem of the individual's capacity for
self-determination is inevitably tied to the feminist perspective.