the life table parameters of schizaphis graminum (rondani) (hemiptera: aphididae) on four commercial cultivars of wheat (kohdasht, pastor, tajan and zagros) were determined in laboratory conditions. fertility life table were constructed using age-specific survivorship (lx) and age-specific fecundity (mx) and subsequently analyzed using jackknife method and anova. there were significant differen...

effects of four pesticides (imidacloprid, dichlorvos, pymetrozine and abamectin) were evaluated on life table parameters of orius albidipennis (reuter). pesticides were used at the concentrations recommended by the manufacturers. the bioassays were carried out using drum-cell method, in a growth chamber at 27 â± 1âºc, r.h. of 65 â± 5% and 16 h photo phase. the net reproductive rate (r0) value f...

the tomato fruit borer, helicoverpa armigera (hã¼bner), is a destructive insect pest of many host crops in iran and worldwide. the effect of different tomato cultivars (sun 6108 f1, rio grande ug, korral, ch falat, hed rio grande and cal jn3) was studied on life table parameters of h. armigera under laboratory (25 â± 1 â°c, 65 â± 5% rh and a photoperiod of 16: 8 (l: d) hours), and on the activi...

From the time of De Moivre (1725), suggestions have been made as to the law of mortality as a mathematical formula, of which the most famous is perhaps that of Gompertz (1825). Since John Graunt (1620–1674) life tables had been constructed empirically. These life tables represented mortality over the whole human lifespan, and it was natural to ask if the mathematical functions defined by the li...

the effect of eight cucumis l. (cucurbitaceae) genotypes, including native cucumber genotypes (hormozgan, bushehr and gilan), greenhouse cucumber genotypes (girtap, negeen, sepehr and pouya) and armenian cucumber (cucumis melo var. flexuosus) was studied on the life table and population growth parameters of aphis gossypii glover to evaluate antibiosis resistance. the experiment was conducted at...

In this paper we explore the life expectancy limits by based on the stochastic modeling of mortality and applying the first exit or hitting time theory of a stochastic process. The main assumption is that the health state or the “vitality”, according to Strehler and Mildvan, of an individual is a stochastic variable and thus it was introduced and applied a first exit time density function to mo...

(iv) un = (a b)/(a b), yn = a + £. If i4 = £ = 1, then un, Vn are the Fibonacci and Lucas sequences, respectively. If A = 3 and 5 =-2, then un, t;n are the Mersenne and Fermat sequences, respectively. If A = 2 and 5 = 1 (so that Z? = 8), then un is called the Pell sequence (see [4, p. 187]), and is denoted Pn; vn may be called the secondary Pell sequence, and denoted i?n, following [7]. For the...