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jeasiq-288
A Comparative Study of Some Methods of Estimating Robust Variance Covariance Matrix of the Parameters Estimated by (OLS) in Cross-Sectional Data
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Abstract

The Classical Normal Linear Regression Model Based on Several hypotheses, one of them is Heteroscedasticity as it is known that the wing of least squares method (OLS), under the existence of these two problems make the estimators, lose their desirable properties, in addition the statistical inference becomes unaccepted table. According that we put tow alternative,  the first one is  (Generalized Least Square) Which is denoted by (GLS), and the second alternative is to (Robust covariance matrix estimation) the estimated parameters method(OLS), and that the way (GLS) method neat and certified, if the capabilities (Efficient) and the statistical inference Thread on the basis of an acceptable but this method requires knowledge and knowledge of the nature of the problem and the private model of the problem, whether the Heteroscedasticity otherwise, the method (GLS) become inappropriate. The second alternative is a matrix contrast common variation fortified it does not require prior knowledge of the nature of your problem model, it's also an easy way and by this method has met with popular and interest in more than two decades by researchers, that the estimated of Robust covariance matrix the estimated parameters method(OLS), shall be according to data that is handled type, and we have dealt with in this study, cross-sectional data where the problem of Heteroscedasticity in contrast may be contained therein(Heteroscedasticity- Consistent Covariance matrix Estimation) and symbolized by the (HCCME) and includes many ways, and we have dealt with in our study of these methods  

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Publication Date
Wed Mar 20 2019
Journal Name
Journal Of Legal Sciences
Open Price Contract- Compertive Study
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The ultimate goal of any sale contract is to maximize the combined returns of the parties, knowing that these returns are not realized (in long-term contracts) except in the final stages of the contract. Therefore, this requires the parties to the contract to leave some elements open, including the price, because the adoption of a fixed price and inflexible will not be appropriate to meet their desires when contracting, especially with ignorance of matters beyond their will and may affect the market conditions, and the possibility of modifying the fixed price through The elimination is very limited, especially when the parties to the contract are equally in terms of economic strength. Hence, in order to respond to market uncertainties, the

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Publication Date
Fri Jul 29 2022
Journal Name
Journal For Vascular Ultrasound
A Comparative Study of the Right and Left Carotid Arteries in Relation to Age for Patients With Diabetes and Hypertension
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Introduction:

Age, hypertension, and diabetes can cause significant alterations in arterial structure and function, including changes in lumen diameter (LD), intimal-medial thickness (IMT), flow velocities, and arterial compliance. These are also considered risk markers of atherosclerosis and cerebrovascular disease. A difference between right and left carotid artery blood flow and IMT has been reported by some researchers, and a difference in the incidence of nonlacunar stroke has been reported between the right and left brain hemispheres. The aim of this study was to determine whether there are differences between the right and left common carotid arteries and internal carotid arteries in patient

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Publication Date
Fri Jun 30 2017
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Comparative Study for Removal of Zn+2 Ions from Aqueous Solutions by Adsorption and Forward Osmosis
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The aim of this paper was to investigate the removal efficiencies of Zn+2 ions from wastewater by adsorption (using tobacco leaves) and forward osmosis (using cellulose triacetate (CTA) membrane). Various experimental parameters were investigated in adsorption experiment such as: effect of pH (3 - 7), contact time (0  - 220) min, solute concentration (10 - 100) mg/l, and adsorbent dose (0.2 - 5)g. Whereas for forward osmosis the operating parameters studied were: draw solution concentration (10 - 150) g/l, pH of feed solution (4 - 7), feed solution concentration (10 - 100) mg/l. The result showed that the removal efficiency by using adsorption was 70% and the removal efficiency by using forward osmosis was 96.2 %. 

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Publication Date
Sat Dec 01 2018
Journal Name
Al-khwarizmi Engineering Journal
Study the Characterizations of Cement Mortar by Nano Pozzolanic Materials Additions
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This study involves adding nano materials and interaction with cement mortar behavior for several mortar samples under variable curing time with constant water to cement ratio (W/C = 0.5). The effects of adding nano materials on the microstructure of cement mortar were studied by (Scanning Electronic Microscopy (SEM) and X-Ray (for samples at different curing time 28 and 91 days. Small ratio replacements of nano particles (SiO2 or Al2O3) were added to Ordinary Portland Cement (OPC) type (I). The percentage of nano materials additives replacement by weight of ordinary Portland cement includes (1, 2, 3, 4 and 5%) for both types of nano materials with constant (W/C) ratio, also the amount of the fin

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Publication Date
Fri Oct 20 2023
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
A Morphological Study of Some Silene L. Species of Caryophyllaceae family in Iraq
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The current works included morphological features study (vegetative and floral parts) for five species of the genus Silene L., S. ampullata, S. chlorifolia, S. colorata, S. conoidea and S. longipetala belong to the family Caryophyllaceae, samples were collected from various areas of northern Iraq. Confirmation in the description was on the most critical parts of the plant, including the shape of the leaves, length, and shape of the calyx tube and venation, the modification shapes of coronal scales petals and appendages, anther ornamentation and structures of pistils. Images enhanced the morphological characteristics under study. Information on the locations and dates of the collection

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Publication Date
Wed Dec 01 2021
Journal Name
Journal Of Physics: Conference Series
Analytical Study of the Royal-Jelly Effect on Sperms Morphological Characteristics and some Liver Function Parameters and their Correlation with some Antioxidants in Male Albino Rats Treated with Pregabalin Drug
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Abstract<p>In recent years, the consideration of natural products as anti-inflammatory and antioxidative treatments has more interested worldwide. Moreover, natural products are easily obtained and are relatively safe the Royal jelly (RJ) is one of them. The current study was carried to evaluate the effects of pregabalin (PGB) on physiological activity of sperms, reproductive hormones assay and some biochemical analysis. Forty (40) male albino rats (10-weeks-old) were divided into four groups (10 rats each): G1 (treated with PGB drug, 150 mg/kg B.wt (Lyrica-Pfizer-Pharmaceutical Industries), G2 (treated with RJ 1g/kg), G3 (treated with PGB drug and RJ together), and G4 control treated with norma</p> ... Show More
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Publication Date
Thu Nov 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
Estimate size sub-population by Killworth method
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The aim of the thesis is to estimate the partial and inaccessible population groups, which is a field study to estimate the number of drug’s users in the Baghdad governorate for males who are (15-60) years old.

Because of the absence of data approved by government institutions, as well as the difficulty of estimating the numbers of these people from the traditional survey, in which the respondent expresses himself or his family members in some cases. In these challenges, the NSUM Network Scale-Up Method Is mainly based on asking respondents about the number of people they know in their network of drug addicts.

Based on this principle, a statistical questionnaire was designed to

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Publication Date
Sun Feb 10 2019
Journal Name
Journal Of The College Of Education For Women
Woman’s Identity Crisis in the Clash of Cultures: A Study of Betool Khedairi’s Novel: A Sky So close
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This paper is an attempt to clarify the impact of Postcolonialism, one of the most
challenging fields of study that has emerged in recent years, on representations of women in
once-colonised countries and in Western locations. It discusses the influence of cultural
differences on the status and identity of a woman who experience ‗multiculturalism‘. The
study is an analytical reading of a contemporary novel written by the Iraqi writer Betool Al-
Kudairi. The emphasis lies on the clash between two different cultures and traditions
represented by the British mother and the Iraqi father and its effect on the life and identity of
the protagonist. The main focus is on idea of ‗hybrid identity‘ and the absence of th

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Publication Date
Sat Jul 01 2017
Journal Name
Al–bahith Al–a'alami
The Use of Digital Public – Relations in the Work of Iraqi Universities: A Survey Study of the Workers in the Departments of Public Relations
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the digital public relations aim at make the workers getting the necessary information about the governmental institutions where they work and the enveronment surrounding them. it also tries to let the workers get the special knowlege of tthe publich relations and their jobs like the works of planning , arranging the active communication and executive skills needed in their writing , editing , special art skills for designing , production and technological skills to deal with the computer.
the problem of the research includes some questions as :
1- what are the uses achieved by degetal public relations workers at Iraqi universities (Baghdad, Mustansiriya, and Iraqi)
2- what are the tools used to apply digital public relations

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Publication Date
Fri May 16 2025
Journal Name
Journal Of Baghdad College Of Dentistry
An evaluation of canal transportation and centering ability at different levels of root canals prepared by self-adjusting file using computed tomography (A comparative study)
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Background: The new concepts and technologies continue to change the dynamics of endodontic practices in the world. Rapid and significant changes in techniques, instrument design, and the type of metals used to manufacture endodontic instruments which have been made during the last few years in an attempt to overcome canal preparation errors. The purpose of this study is to measure and compare canal transportation and centering ability of Self Adjusting File with two rotary nickel-titanium (Ni-Ti) systems, ProTaper and BioRaCe at different levels. Material and Methods: Forty five distal roots of mandibular first molars with moderate curvature were selected using Schneider method. Roots were divided randomly into 3 groups of 15 each and were

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