The present paper focuses on the nature of the different interactions between cometary nucleus and tail with solar wind. The dynamics of the comet will impose many features that provide unique behavior of the comet when entering the solar system. These features are reviewed in this paper and few investigations are made. The calculations made in this work represent the analysis and interpretation of the different features of the comet, such as perihelion and eccentricity dependence on the gas production rate, and the dependence of the latter on the composition of the comet nucleus. The dependences of the heliocentric, bow shock, contact surface, and stand-off distances with gas production rate for many types of comets that cover linear and n

Through this study, the following has been proven, if  is an algebraically paranormal operator acting on separable Hilbert space, then  satisfies the ( ) property and  is also satisfies the ( ) property for all . These results are also achieved for  ( ) property.    In addition, we prove that for a polaroid operator with finite ascent then after the property ( ) holds for  for all.

      Let A, and N  are a semiring ,and  a left A- semimodule, respectively. In this work we will discuss two cases: 

1. The direct summand of π-projective semi module is π-projective, while the direct sum of two π-projective semimodules in general is not π-projective . The details of the proof will be given.
2. We will give a condition under which the direct sum of two π-projective semi modules is π-projective, as well as we also set conditions under which π-projective semi modules are projective.

This paper focuses on developing a strategy to represent the -connected ominoes using an abacus. We use the idea of -connected ominoes with respect to a frame in modelling nested chain abacus. Then, we formulate and prove the unique connected partition for any -connected ominoes. Next, the topological structure of nested chain abacus is presented.

Digital technologies have come to shake up the traditional paradigm of learning, and to change the existing relationship of "know-teaching" to put in place a key concept of the time is "to accompany through digital tools Our intervention is part of a technical-pedagogical approach and will focus on an action research work in which we will try:
First, to present on line an accessible digital device that facilitates and organizes project planning and provides means to govern and control the quality of administrative acts.
Next, We will show the first results of the experimentation of this tool in our context of research represented by 355 directors of the secondary schools of the provincial delegation of Taza. Morocco, pointing out a

Well dispersed Cu2FeSnSe4 (CFTSe) nanofilms were synthesized by hot-injection method. The structural and morphological measurements were characterized using XRD (X-ray diffraction), Raman spectroscopy, SEM (scanning electron microscopy), and TEM (transmission electron microscopy). Chemical composition and optical properties of as-synthesized CFTSe nanoparticles were characterized using EDS (energy dispersive spectroscopy) and UV-Vis spectrophotometry. The average particle size of the nanoparticles was about 7-10 nm. The UV-Vis absorption spectra showed that the synthesized CFTS nanofilms have a band gap (Eg) of about 1.16 eV. Photo-electrochemical characteristics of CFTSe nanoparticles were studied and indicated their potential application

Back ground : Fever is a common medical problem in
children. parents have been shown unrealistic fears of
harmful effects of fever in their children. Resulting in
inappropriate management of fever in their children.
Objective: the objective of this study was to survey
parents about their knowledge andattitude concerning fever
in their children.
Methods : The study involved random selection of
parents who brought their febrile children to emergency
department or out-patient clinics of five teaching and non
teaching hospitals in Baghdad from first of October to end
of December 2002.
Parents of 400 febrile children were interviewed using a
standard questionnaire to obtain sociodemographic
informatio