نتایج جستجو برای: spatial distribution

تعداد نتایج: 914935  

ژورنال: پژوهش های ریاضی 2022

The common methods for spatial risk estimation are investigated for a stationary random field. Because of simplifying, lets distribution is known, and parametric variogram for the random field are considered. In this paper, we study a nonparametric spatial method for spatial risk. In this method, we model the random field trend by a local linear estimator, and through bias-corrected residuals, ...

Journal: :iranian journal of health sciences 0
zahra nourbakhsh department of environmental management, school of environment and energy, islamic azad university, science and research branch, tehran, iran naser moharamnejad department of environmental management, school of environment and energy, islamic azad university, science and research branch, tehran, iran naser mehrdadi department of environmental engineering, school of environment, university of tehran, tehran, iran amir hesam hassani department of environmental engineering, school of environment and energy, islamic azad university, science and research branch, tehran, iran hossein yousefi department of renewable energies and environmental engineering, school of new sciences and technologies, university of tehran, tehran, iran

abstract background and purpose:in many regions especially in the north of iran groundwater is the most important resource for drinking supply. a present study was carried out in the tajan plain in northern iran. the aim of this study was to evaluate the quality of groundwater. materials and methods:in order to constructing the groundwater quality index (gwqi) 3 main levels were composed select...

Journal: :تحقیقات آب و خاک ایران 0
آرش کرمی کارشناسی ارشد، دانشگاه تهران قوام الدین زاهدی دانشیار، دانشگاه تهران جهانگیر فقهی دانشیار، دانشگاه تهران

some soil physical and chemical characteristics were analyzed in order to reveal the relationship between forest soils and regeneration patches. gorazbon district of kheyrud was selected as a case study for the research area. all regeneration patches were recorded using gps device. to assess the spatial structure and to quantify the metrics of regeneration patches, analyzing of landscape metric...

Journal: :تحقیقات جغرافیایی 0
حسین عساکره زهره سیفی پور گروه جغرافیای دانشگاه زنجان

due to deep, complex and everlasting interaction between precipitation and climatic elements-factors, there are changes and varieties in both time and space dimensions. so that climate experts and related scientists take their attentions to this phenomenon. an approach to do this kind of investigations is to describe spatial variations based on spatial statistics. in this paper the main object ...

Maghsoudlou, Abdol Wahab, Olad Azimi, Niloofar,

Abstract In the present study, the structure of macrobenthos communities of Chabahar Bay prior to monsoon in 2016 was investigated.  We identified 87 species contain 22 amphipods species, 14 species of other crustaceans, 31 species of molluscs, and 20 polychaets species, where amphipods followed by polychates were dominant taxa. The PERMANOVA test revealed that there is a significant difference...

ژورنال: علوم آب و خاک 2006
محمدحسن راشد محصل, , مهدی نصیری ‌محلاتی, , آسیه سیاه‌مرگویی, , حمـید رحیمیان‌ مشهدی, , محمد بنایان‌اول, ,

This study was conducted in a sugar beet field at Collage of Agriculture Experimental Station, Ferdowsi University of Mashhad, Iran. In order to describe the pattern of spatial variations and density of Chenopodium album, Solanum nigrum, Amaranthus sp., Portulaca oleracea, Echinochla crus-galli, and Convulvulus arvense as the main prevalent annual and perennial weeds of sugar beet fields, geost...

Presence of toxic metals in agricultural soils can impose adverse health impact on consumers. The main purpose of this study was to determine spatial distribution of elements Fe, Sb, Mn in agriculture soils and crops of Hamedan Province in Iran. Soil samples (0-20 cm depth) were collected from an area of 2831 km2.  Iron, Antimony and Manganese in samples of soil and agricultural crop...

Journal: :جنگل و فرآورده های چوب 0
فریده امیدوار حسینی دانشجوی کارشناسی ارشد رشتۀ جنگلداری، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، تهران، ایران رضا اخوان استادیار پژوهش، مؤسسۀ تحقیقات جنگل ها و مراتع کشور، تهران، ایران هادی کیادلیری استادیار گروه جنگلداری، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات، تهران، ایران اسداله متاجی دانشیار گروه جنگلداری، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات، تهران، ایران

one of the most visible aspects of a forest stand structure is the spatial patterns of trees. competition affects on forest structure and its understanding is important, when the purpose of forest management is to imitate the dynamic of natural ecosystems. for this purpose, an unmanaged intact forest was selected with 26 hectares area. all chestnut leaf oak (quercus castaneifolia) trees with a ...

The process of spatial distribution of urban services in order to provide equitable access to opportunities and reduced regional disparities, and earning the highest citizen satisfaction are among the main challenges facing urban management. This requires knowledge of the current status of spatial distribution of public services in the city, followed by optimal resource allocation under varying...

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