We call a module M , quasi-catenary if for each pair of quasi-prime submodules K and L of M with K L all saturated chains of quasi-prime submodules of M from K to L have a common finite length. We show that any homomorphic image of a quasi-catenary module is quasi-catenary. We prove that if M   is a module with following properties: (i) Every quasi-prime submodule of M has finite quasi-height;...

this study aims at analyzing spatial pattern and associations of fagus oriantalis lipsky in different vertical classes in intact beech forests. data collection was done in 25 ha plot in gorazbon district of educational and experimental forests of university of tehran. species and dbh of all trees with dbh > 7.5 cm were recorded. the location of each tree was determined using azimuth and distanc...

in the current research, wind energy potential at yazd synoptic stations, which contain wind data with 10 years statistic period and beyond, including yazd synoptic station (1976-2006), tabass (1987-2006), robate poshte badam (1992-2006), bafgh (1993-2006) and marvast (1997-2006), has been studied. wind data were obtained from the recorded data at yazd meteorology organization. the data were re...

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...

The gravitational component of water potential and frictional resistance during transpiration lead to substantial reductions in leaf water potential (Psi(l)) near the tops of tall trees, which can influence both leaf growth and physiology. We examined the relationships between morphological features and gas exchange in foliage collected near the tops of Douglas-fir (Pseudotsuga menziesii (Mirb....

the effects of initial spacing layout on some allometric characteristics of 12-year-old quercus castaneifolia trees grown in central mazandaran, north of iran were examined. trees were planted in 5 different layouts (1?1, 1.5?1.5, 2?2.5, 2?3 and 4?4 m). tree height, diameter at breast height, natural pruning height and the survival of trees were recorded in each sample plot. tree basal area and...

The effects of initial spacing layout on some allometric characteristics of 12-year-old Quercus castaneifolia trees grown in Central Mazandaran, north of Iran were examined. Trees were planted in 5 different layouts (1?1, 1.5?1.5, 2?2.5, 2?3 and 4?4 m). Tree height, diameter at breast height, natural pruning height and the survival of trees were recorded in each sample plot. Tree basal area and...

Canopy height is a key variable in tropical forest functioning and for regional carbon inventories. We investigate the spatial structure of the canopy height of a tropical forest, its relationship with environmental physical covariates, and the implication for tropical forest height variation mapping. Making use of high-resolution maps of LiDAR-derived Digital Canopy Model (DCM) and environment...

Age, height, weight and body mass index (weight/height2) of women finalists from seven running events (100 m, 200 m, 400 m, 800 m, 1500 m, 3000m and marathon) are analysed. The data on 174 runners are derived from four Olympics (Munich, Montreal, Moscow and Los Angeles). On average endurance runners (3000 m and marathon are 4.8 years older, 6 cm shorter and 5 kg lighter for their height than sp...