for half a century, the limitations of obtaining cross-combinations in lilies because of the incompatibility and incongruity between different varieties have been known. somatic hybridization is one of the most powerful tools for achieving distant interspecific hybrids. for this purpose, protoplast preparation is a first and important step in efficient system for the regeneration of plants from...

a stratigraphic section from the tirgan formation was selected in arkan village nearby bojnourd city in order to study echinoderm fauna systematically. many specimens of echinoderms, especially toxasteridae which is associated with brachiopods were collected and studied systematically in this paper. microscopie slides were also prepared and studied. all slides contain benthic foraminifers and c...

due to their widespread availability, sandstones are commonly used as a natural stone for buildings, monuments and sculptures. in thecurrent study, nine sandstone samples from the upper red formation (specified by the letters a, b, c, cg, s, s1, sh, tr and min)were studied from a petrophysical point of view and their durability was evaluated. then, their suitability as building stones wasassess...

the investigated section cropping out in kuh-e-banesh, zagros basin (southern iran) is represented by limestone, cherty beds and marllevels bearing abundant planktonic foraminifers, radiolarian microfaunas, and ammonite imprints. for the first time, well to moderatelypreserved forms of planktonic foraminifera have been extracted from black shale and marls levels. extracted biota was studied wit...

suppose that $h$ is a subgroup of $g$‎, ‎then $h$ is said to be‎ ‎$s$-permutable in $g$‎, ‎if $h$ permutes with every sylow subgroup of‎ ‎$g$‎. ‎if $hp=ph$ hold for every sylow subgroup $p$ of $g$ with $(|p|‎, ‎|h|)=1$)‎, ‎then $h$ is called an $s$-semipermutable subgroup of $g$‎. ‎in this paper‎, ‎we say that $h$ is partially $s$-embedded in $g$ if‎ ‎$g$ has a normal subgroup $t$ such that $ht...

this paper presents a new nonlinear mathematical model to solve a cell formation problem which assumes that processing time and inter-arrival time of parts are random variables. in this research, cells are defined as a queue system which will be optimized via queuing theory. in this queue system, each machine is assumed as a server and each part as a customer. the grouping of machines and parts...

the present study is concerned with measuring and simulating soot formation and combustion in turbulent liquid fuel spray flames. soot concentrations inside the combustor are measured by filter paper technique. the simulation is based on the solution of the fully-coupled conservation equations for turbulent flow, chemical species kinetic modeling, fuel droplet evaporation and combustion and soo...

fitzhugh-nagumo (fhn) model is a famous reaction-diffusion system which first introduced for the conduction of electrical impulses along a nerve fiber. this model is also considered as an abstract model for pattern formation. here, we have used the cellular automata method to simulate the pattern formation of the fhn model. it is shown that the pattern of this model is very similar to those of ...

statistical studies on palynology contents of late cretaceous to paleocene age gurpi formation in a surface section in zagros basin,sw iran indicate changes in abundance, species diversity, ratio of spiniferites to cyclonephelium (s/c), palynological marine index(pmi) values and organic facies. these palynological variations clearly reflect fluctuations in relative sea-level and depositionalenv...

the nayband formation was measured and sampled in parvadeh area, southern tabas city. in this area, this formation has a thickness of 1410 m, dividing into four members, namely gelkan, bidestan, howz-e-sheikh and howz-e-khan. a total 573 samples were treated for palynological analysis, and only 120 samples were productive. a total of 57 miospore taxa and 11 plant macrofossil were encountered. b...