نتایج جستجو برای: narrow valleys and high mountains

تعداد نتایج: 17085710  

Journal: :The New phytologist 2011
Rui Wang Jin-Feng Wang Zhi-Jing Qiu Bin Meng Fang-Hao Wan Yin-Zheng Wang

• With growing concerns over serious ecological problems, a particular challenge is to reveal the complex mechanisms underlying rapid expansion of invasive species. Ageratina adenophora is of particular interest in addressing this question. • We used geographic information systems and logistic regression to identify the geographic and environmental factors contributing to the presence of A. ade...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه اراک - دانشکده علوم 1392

the history of plant’s used for mankind is as old as the start of humankind. initially, people used plants for their nutritional proposes but after the discovery of medicinal properties, this natural ?ora became a useful source of disease cure and health improvement across various human communities. berberis vulgaris is one of the medicinal plants used in iranian traditional medicine. berberis ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1390

abstract ion selective electrodes (ises) are electrochemical sensors that respond selectivity to the activity of ionic species. an ion-selective electrode is an electrochemical device that uses a thin selective membrane or film as the recognition element, and is an electrochemical half-cell equivalent to other half-cells of the zeroth (inert metal in a redox electrolyte). in common methods o...

Journal: :Remote Sensing 2022

Linking snow cover frequency (SCF) and atmospheric circulation is vital for comprehension of hemispheric-scale change mechanisms accurate forecasting. This study combined MODIS imagery with meteorological observations to investigate the variation annual SCFs in Qilian Mountains. Results indicated that more than 80% SCF distributed at high elevations mostly on northern slopes, greater west east....

2013
Arun Bhakta Shrestha

The Hindu Kush Himalayas (HKH) is a mountain system of extremes with great influence over the Asian continent. The system stretches 3,500 km over eight countries, from Afghanistan in the west to Myanmar in the east. It is the world’s largest and highest mountain system, with more than 30 peaks measuring over 7,600 m. It is also the youngest mountain system on Earth and still tectonically active...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت دبیر شهید رجایی - دانشکده علوم انسانی 1393

according to research, academic self-concept and academic achievement are mutually interdependent. in the present study, the aim was to determine the relationship between the academic self-concept and the academic achievement of students in english as a foreign language and general subjects. the participants were 320 students studying in 4th grade of high school in three cities of noor, nowshah...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده ادبیات و علوم انسانی دکتر علی شریعتی 1389

the current study examined iranian undergraduate efl students’ willingness to communicate with regard to their vocabulary knowledge. in general, participants were somewhat willing to communicate in english. the total mean score of 730 university students’ perception of willing to communicate was 83.53 out of 135. results, regarding four parts of willingness to communicate, revealed that part...

Journal: :تحقیقات جغرافیایی 0
مریم عسگری گروه جغرافیای طبیعی- دانشگاه تبریز معصومه رجبی گروه جغرافیای طبیعی- دانشگاه تبریز فریبا کرمی

abstract: the aim of this study is analysis of drainage basins neotectonic in the north slope of bozqoosh mountains by geomorphological methods. to attain this aim, it used of field observation, areal photographs and five geomorphic indexes in 20 basins of the north slope of bozqoosh mountains. indexes were calculated by topography maps (1: 50000), geological maps (1: 100000) and areal photogr...

2013
Wei-Kuo Tao Di Wu Toshihisa Matsui Christa Peters-Lidard Stephen Lang Arthur Hou Michele Rienecker Walter Petersen Michael Jensen

[1] Previous observational studies have identified three different types of diurnal precipitation variation over the conterminous U.S.: localized afternoon rainfall maxima over the Mississippi and Ohio valleys, propagating mesoscale convective systems (MCSs) from the Rocky Mountain region, and propagating MCSs over the Appalachian Mountains. This study focuses on the second type, which involves...

2003
J. Stock W. E. Dietrich

[1] The sculpture of valleys by flowing water is widely recognized, and simplified models of incision by this process (e.g., the stream power law) are the basis for most recent landscape evolution models. Under steady state conditions a stream power law predicts that channel slope varies as an inverse power law of drainage area. Using both contour maps and laser altimetry, we find that this inv...

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