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 ...

in order to study the effect of elevation on quantitative and qualitative characteristics of the humid forests of guilan shafaroud, series 17, 16 and 7 were selected that fall in to three height classes; class 1 (‏less than 500 m), class 2 (‏500 – 1000 m) and class 3 (‏1000 – 1600 m). in height class 1, 2 and 3 sample plots were determined as 4, 15 and 20 respectively and each sample plot was 0...

construction of forest roads disorders the natural trend of water movement. it is vital to make ditch and cross line drainage culvert to prevent the area from being destroyed and conduct the water of streems and vallies. determination of culvert diameters depends on the information of area discharge, physiographic characteristic, vegetation cover and site land use. in order to determine the amo...

A small placental surface area at birth is associated with an increased risk of hypertension in the offspring in later life. Preeclampsia is associated with impaired implantation and with increased blood pressure in the offspring. We hypothesized that preeclampsia would be associated with a small placental surface area. We studied placental size in 6410 deliveries at the Helsinki University Cen...

Real networks, including biological networks, are known to have the small-world property, characterized by a small "diameter", which is defined as the average minimal path length between all pairs of nodes in a network. Because random networks also have short diameters, one may predict that the diameter of a real network should be even shorter than its random expectation, because having shorter...

One of the promising methods to search for life on extra-solar planets (exoplanets) is to detect life’s signatures in their atmospheres. Spectra of exoplanet atmospheres at the modest resolution needed to search for oxygen, carbon dioxide, water, and methane will demand large collecting areas and large diameters to capture and isolate the light from planets in the habitable zones around the sta...

Mapping mean axon diameter and intra-axonal volume fraction may have significant clinical potential because nerve conduction velocity is directly dependent on axon diameter, and several neurodegenerative diseases affect axons of specific sizes and alter axon counts. Diffusion-weighted MRI methods based on the pulsed gradient spin echo (PGSE) sequence have been reported to be able to assess axon...

A design diagram of comb formation roller in resilient stems is given. Comb-forming consists support and small discs, as well elastic rods. Elastic rods are installed along the perimeter diameter disks through their holes. Analytical dependences mathematical models obtained for determining distance between disks, diameter, length number One-factor experiments were carried out to substantiate It...

a new species of cassiduloid echinoids, pygaulus baghinensis is reported for the first time from aptian sediments of baghin area, west of kerman, iran. the diagnostic features of the species are centrally positioned of the apical disc and approximately low profile of the test. variation in gonopore size in different individuals allows to conclude that p. baghinensis is sexually dimorphic. speci...

BACKGROUND AND PURPOSE Conventional X-ray angiography lacks the sensitivity and spatial resolution needed to detect small amounts of iodinated contrast material and to quantitate diameters of the small vessels in the brain. The purpose of this study was to ascertain whether digitized synchrotron radiation microangiography, with the use of a high-definition TV camera system, can accurately show ...