a simple but novel and applicable approach is proposed to solve the problem of smoothing effect of ordinary kriging estimate which is widely used in mining and earth sciences. it is based on transformation equation in which z scores are derived from ordinary kriging estimates and then rescaled by the standard deviation of sample data and the sample mean is added to the result. it bears the grea...

Asexual organisms that are descended from ancient asexual lineages defy current thinking on the evolution of sexual reproduction; theoreticians have been anxious to explain away their existence. However, a number of groups of organisms, from ferns to rotifers, have been suggested to be anciently asexual, and favourable evidence is being accumulated. Furthermore, new techniques for assessing cla...

conditions throughout the test. The hens were provided nutrients to meet the needs of all the hens based upon compilation of the breeder recommendations. The eggs from these strains were collected every 28 days from the previous 24 hrs production. Once collected the quality and compositional properties of the eggs such as pH, solids, whipping height, Haugh units and angel food cakes were evalua...

the pollution of aquatic ecosystems may affect natural reproduction of fish populations by decreasing the fertilization efficiency. among the various sources of pollution, heavy metals are important group, being found in both freshwater and marine environment. the present study investigated changes of sperm characteristics of caspimyzon wagneri when exposed to manganese (mn). spermatozoids were...

the objective was to quantify and compare cow cervical morphology on oestrus vs. non-oestrus daysusing a new farm technology. the cervical tissues were videotaped using a cervixscope involving newcamera equipment in four holstein cows on multiple oestrus and non-oestrus days to score tissue morphology as altered by oestrus. the non-oestrous days were in diestrus phases. the videotaped records w...

in this study, the morphological and histological studies of male and female gonads in mudskipper, periophthalmus waltoni koumans, 1941 from helleh estuary (bushehr province, southwestern iran) were performed to determine its gonadal development stages and histo-morphological characteristics. sampling was done from april 2010 to march 2011 and a total of 81 individuals were collected by hand ne...

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...