the cypress tree mealybug, planococcus vovae (nasonov) (hem., pseudococcidae) is one of the most important pests of cypress trees, especially cupressus semprevirens fastigiata l. in iran. a survey was carried out to determine the natural enemies of cypress tree mea-lybug in tehran province, during 2004-2005. as a result of this study, 17 species of preda-tors, parasitoids and hyperparasitoids b...

A quartz crystal oscillator can be thought ofas a resonator connected across an amplifier considered asa nonlinear dipole the impedance of which depends on theamplitude of the current that flows through it. The non-linear amplifier resistance and reactance are obtained byusing a time domain electrical simulator like SPICE (Simu-lation Program with Integrated Circuit Emph...

the relocation of nutrients and water fluxes to the forest floor varies spatially due to partition of rainfall into throughfall and stemflow by tree canopies. in this study, nutrient concentrations of rainfall and stemflow were measured for seven rainfall events in chaboksar area in the hyrcanian ecozone of iran composed of juglans regia linn and cup. sempervirens l. var. fastigiata where such ...

the aim of this study is comparison of soil characteristics and biodiversity in plantation of bald cypress and caucasian alder forest stands in kludeh region (mazandaran province). in order to study biodiversity in forest stands and control region, 10 sample plots (releve) were selected and the name and abundance of plant species of the forest floor were recorded. biodiversity of herbal plants ...

The survey gives an overview of the achievements in topology of real algebraic varieties in the direction initiated in the early 70th by V. I. Arnold and V. A. Rokhlin. We make an attempt to systematize the principal results in the subject. After an exposition of general tools and results, special attention is paid to surfaces and curves on surfaces.

Alstromeria has beautiful flowers that is popular in the world. One of the most problem in commercial of this flower is ethylene sensitivity and bacterial contamination in stem end of cut flowers. In this experiment, effect of essential oils of bitter orange (0, 25 and 50 mg l-1) and lawson cypress (0, 100 and 200 mg l-1) and nonchemical treatment (with and without) with 18 treatments, 3 replic...

Identification of widespread species collected from islands can be challenging due to the potential for local ecological and phenotypic divergence in isolated populations. We sought to determine how many species of the spruce budworm (Choristoneura fumiferana) complex reside in Cypress Hills, an isolated remnant coniferous forest in western Canada. We integrated data on behavior, ecology, morph...