This paper study two stratified quantile regression models of the marginal and the conditional varieties. We estimate the quantile functions of these models by using two nonparametric methods of smoothing spline (B-spline) and kernel regression (Nadaraya-Watson). The estimates can be obtained by solve nonparametric quantile regression problem which means minimizing the quantile regression objective functions and using the approach of varying coefficient models. The main goal is discussing the comparison between the estimators of the two nonparametric methods and adopting the best one between them
Degradation of soil quality is an inevitable consequence of modifications to the characteristics of the soil that contribute to a decrease in ecosystem services. Numerous stressors, including chemical, biological, and physical ones, as well as those originating from both natural and artificial sources. The most prevalent kind of soil contamination that contaminates soil biota is agrochemicals. Soil is the most common place for xenobiotic dumping, which makes it the most probable source of other natural resources' pollution, such as surface and ground waters, based on the results of several studies. The danger to the environment posed by polluted soils is influenced by a variety of biological and physicochemical mechanisms that regulate the
... Show MoreThe research aims to identify the relationship between spatial ability and the physical structure of concepts to the students of the Faculty of Education for Pure Sciences / Ibn al-Haitham، research involved students from the third class / morning study for the year 2011/2012 totaling (98) male and female students ،distributed into three groups which were selected randomly . The number of students (26 males and females) represented research sample after excluding repeaters and absentees، the research included two tests ; one test of spatial ability، which included (20) items and other test the physical structure of concepts، which included (12) items distributed into four domains ، the first (linking b
... Show MoreThe geopolities considering as build from the basies builds of the polities
geography, participating in appointing the military geography, and submit to it
geo-polities purveyed, playing important role to appointing the builds relations
between the high strategy and the military strategy, while the foreign polities of
the state, which considering as a tool for the state outside it environment and
borders playing the role of the performance and the functional works to the
peaceful or hostile reaction according to the geopolities purveyed which
participating in amassing the recourse for the economical, political, social,
military and technology strategies and activating it to achieving the state interests
and obj
Purpose: The aim of this study is to examine knowing the real role and impact of manufacturing flexibility on competitiveness through operations management practices, which is to determine the role and impact of manufacturing flexibility on competitiveness directly in the General Company for the Battery Industry. On the other hand, identifying the indirect role of flexible manufacturing systems in enhancing competitiveness. Theoretical framework: The main purpose of the theoretical framework is to identify all the dimensions and variables included in the current study, and thus form a deep scientific view of the study and its variables. Design/methodology/approach: field coexistence, personal interviews, and classification of
... Show MoreThe interaction in the city is reflected in the movement of people motivated by their activities and their economic and social goals, which include many variables subject to the planning process in the interpretation of this movement and the mapping of trends of transport intensity through the concept of transport function and its functional relationships with the uses of the earth in the sustainability and effectiveness of the movement of transport and Economic activity and population movement. Transport planners are concerned with the requirements of land use, which are linked to and included in the transport planning process as a factor for the future transport needs. There is a strong relationship between the transport system
... Show MoreThe aim of this research is to construct a three-dimensional maritime transport model to transport nonhomogeneous goods (k) and different transport modes (v) from their sources (i) to their destinations (j), while limiting the optimum quantities v ijk x to be transported at the lowest possible cost v ijk c and time v ijk t using the heuristic algorithm, Transport problems have been widely studied in computer science and process research and are one of the main problems of transport problems that are usually used to reduce the cost or times of transport of goods with a number of sources and a number of destinations and by means of transport to meet the conditions of supply and demand. Transport models are a key tool in logistics an
... Show MoreAbstract Introduction: Aphthous stomatitis is a recurring oral ulceration condition that affects a significant proportion of the population. While several factors have been proposed to contribute to its occurrence, the link between caffeine consumption, anxiety levels, and the development of aphthous stomatitis remains unknown. This survey-based study aimed to understand the association between coffee, anxiety, and the development of aphthous stomatitis in this specific demographic, which can provide useful insights for medical management as well as preventive strategies. Material and methods: A structured online questionnaire was distributed via various social media platforms targeting a sample of the Armenian population. The quest
... Show MoreThis narrative review focused on research investigating the impact of loneliness on the prevalence of dementia and its relationship with other risk factors. A comprehensive and rigorous search was conducted using a variety of scientific databases with specific keywords to identify all prior studies that examined the correlation between dementia and loneliness. The inquiry was confined to articles published in English from January 2017 to March 2024. The narrative review identified a consensus regarding the role of loneliness in enhancing the risk of all‐cause dementia, with a particular emphasis on the subjective perception of loneliness. This phenomenon may be caused by the sensations of exclusion, discrimination, and alienation that are
... Show MoreWater one of the most important sources Which is no doubt essential for life surviving, water is vital in many sectors of life e.g. ( agriculture, industrial, power and so many things can’t be restricted on the mentioned items, water has become major problem facing the world today. Competition over water resources between nations has made it as a vital commodity and a justification for waging wars against its neighbor’s countries, there are currently 263 rivers that either cross or demarcate international political boundaries. Geographically, Europe has the largest number of international basins (69), followed by Africa (59), Asia (57), North America (40), and South America (38).The absolute numbers of international basins, as well as t
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