Nucleocytoplasmic Gynodioecy

We study the evolution of a gynodioecious species under mixed-mating through a nucleocytoplasmic male sterility model. We consider two cytoplasmic types and a nuclear locus with two alleles. Here, the interaction between one cytoplasmic type and a recessive nuclear male-sterility factor gives rise to only one female genotype, while the remaining types correspond to hermaphroditic plants. We include two fitness paramaters: the advantageous female fitness t of females relative to that of hermaphrodites;and a silent and dominant cost of restoration, that is, a diminished fitness for plants carrying a dominant restorer gene relative to that of hermaphrodites. The parameter related to the cost of restoration is assumed to be present on outcrossing male fertility only. We find that every population converges to a stable population. We also determine the nature of the attracting stable population, which could be a nucleocytoplasmic polymorphism, a nuclear polymorphism or another population with some genotypes absent. This depends on the position of t with respect to critical values expressed in terms of the other parameters and also on the initial population.

Inhibition of the growth and development of mosquito larvae of Culex quinquefasciatus(Diptera:Culicidae) treated with extract from leaves of Pseudocalymma alliaceum(Bignonaceae)

Objective:To determine larvicidal activity of the essential oil,hydrolat and botanical extracts derived from leaves ol Pseudocalymma alliaceum an mosquito larvae of Culex quinquefasciatus.Methods:Groups of twenty lanae were used in the larvicidal assays.The mortality,relative growth rate,the larval and pupal duration and viability was estimated.The essential oil was analyzed by solid phase microextraction using gas chromatography coupled to mass spectrometry.Results:Essential oil at 800 ppm showed larvicidal activity at 24 h with lethal values of LC_(50) and LC_(90) of 267.33 and 493.63 ppm.The hvdrolat at 20% and 10% on 2nd stage larvae showed 100%effectiveness after 24 h.The aqueous extract at 10% had a relative growth index of 0.58.while the ethanolic and methanolic extract obtained values of 0.76 and 0.70 and control reached 0.99.Larvae treated with 10% of methanol,ethanol and aqueous extract showed a reduction in larval duration of 5.00,2.20 and 4.35 days;ethanol extract at 1% provoke decrease of 2.40 days in the development and exhibited an increment of 3.30 days when treated with 0.01%.Aqueous,ethanol and methanol extracts at 10%reduced in 6.15,3.42 and 5.57 days pupal development.The main compounds were diallyl disulfide(50.05%),diallyl sulfide(11.77%) and disulfide di-2-propenyl(10.37%).Conclusions:The study demonstrated for the first time,the larvicidal activity of the essential oil and hydrolat of Pseudocalymma alliaceum:aqueous,ethanol and methanol extracts inhibited the normal growth and development of mosquito larvae,prolonging and delaying larval and pupal duration.

Characteristics of the Elastic Response of Isotropic Linear Micropolar Solids under Imposed Loads

This article proposes a simplified way to solve solid mechanic problems in micropolar elasticity using the solution found in the classic theory of elasticity as a starting point. In this study, an analysis of the linear isotropic micropolar elasticity is conducted based on the properties imposed on the micropolar medium by the constitutive and equilibrium equations. To ascertain how the micropolar medium responses deviate from Hooke’s theory of elasticity, different loading conditions were classified. Three cases have been found so far: the rotational couple response, the quasi-classic equilibrium of momentum response and the general case. This study is the first in a series planned to explore the use of commercial packages of finite element in order to solve micropolar elasticity problems.