An enduring problem in evolutionary biology is the near ubiquity of sexual reproduction despite the inherent cost of transmitting only half the parent's genes to progeny. Queens of some ant species circumvent this cost by using selectively both sexual reproduction and parthenogenesis: workers arise from fertilized eggs, while new queens are produced by parthenogenesis. We show that queens of th...

The near-ubiquity of sexual reproduction in animal species has long been considered a paradox because sexually reproducing individuals transmit only half of their genome to their progeny. Here, we show that the ant Cataglyphis cursor circumvents this cost by using alternative modes of reproduction for the production of reproductive and nonreproductive offspring. New queens are almost exclusivel...

Individuals who reproduce asexually have a two-fold advantage over their sexually-reproducing counterparts as they are able to reproduce twice as fast. Explaining why sexual reproduction is favoured over asexual reproduction therefore remains an important challenge in evolutionary biology. Various mechanisms involving resistance to parasites, adaptation to novel environments and helping to purg...

ISO/TC130 is responsible for international printing standards development. Normative requirements for process control have been centered on solid coloration and TVI. Grey balance and grey reproduction are being addressed in the revision of ISO/WD1 12647-2 (2011). In this regard, the ISO/WD1 12647-2 (2011) takes paper color into consideration when defining grey reproduction aims, but there is a ...

According to life-history theory, reproductive investments involve costs in terms of growth, future fecundity, and/or survival. However, studies to date have often failed to detect costs of reproduction, with survival costs among the less documented. We investigated the cost of reproduction in Helianthemum squamatum (Cistaceae), a short-lived perennial of semiarid Mediterranean environments. Af...

OBJECTIVE To determine the effect of different retraction cord medicaments on surface detail reproduction of polyvinyl siloxane impression materials and compare this effect on any two brands of commercially available polyvinyl siloxane impression materials. MATERIAL AND METHODS Four stainless steel dies were made according to ADA specification no.19. Three dies were treated with aluminium chl...

Abstract
 This research attempted to investigate the effects of double dose vaccination in a non-linear mathematical model Covid-19 infections with special compartments class termed first and second vaccination. The basic reproduction number was obtained, stability analyzed, sensitivity analysis also carried out. Of interest is numerical simulation where impacts contact rate, were studied....