Jacques Loeb [5] is best known for his embryological work investigating parthenogenesis in invertebrates. Artificial Parthenogenesis and Fertilization [4] is a revised and English-translated work from his earlier book, Die chemische Entwicklungserregung des tierischen Eies (1900). Artificial Parthenogenesis [6] describes Loeb?s many and varied methodical experiments to initiate egg [7] developm...

The genetic control of apomixis was studied in numerous segregating progenies originated from intercrossing and selfing of obligate sexual and facultative apomictic parents in Poa pratensis by means of the flow cytometric seed screen. The data support a novel model with five major genes required to control asexual seed formation: the Apospory initiator (Ait) gene, the Apospory preventer (Apv) g...

Facultative automictic parthenogenesis has only recently been confirmed in the most ancient jawed vertebrates, the chondrichthyan fishes (sharks, batoids, and chimeras). To date, however, in both documented cases, the females have only produced a single parthenogen offspring, and none of these have lived for more than 3 days. We present a genetically verified case of automictic parthenogenesis ...

Parthenogenesis in animals is often associated with polyploidy and restriction to extreme habitats or recently deglaciated areas. It has been hypothesized that benefits conferred by asexual reproduction and polyploidy are essential for colonizing these habitats. However, while evolutionary routes to parthenogenesis are manifold, study systems including polyploids are scarce in arthropods. The j...

Phylogenetic studies of asexual lineages and their sexual progenitors are useful for inferring the causes of geographical parthenogenesis and testing hypotheses regarding the evolution of sex. With five known parthenogens and well-studied ecology, Timema walking-sticks are a useful system for studying these questions. Timema are mainly endemic to California and they exhibit the common pattern o...

T he cyclical banks have different behavior than other banks. The structure of the balance sheet in cyclical banks is different from anti-cyclical banks. The cyclical banks have a relationship between leverage growth and asset growth while the other banks have no relationship between asset growth and leverage growth in the banking system. This relationship depends on the structure of...

The problem of the maintenance of anisogamous sex is addressed by considering the effect of fertilization on the fitness of parthenogenetic females when such fertilization yields inviable triploid progeny. We consider four types of parthenogenesis: (i) apomixis, (ii) homogametic amphimixis, (iii) heterogametic amphimixis, and (iv) homogametic automixis. Homozygous sexual populations are genetic...

We consider the multiple shift scheduling problem modelled as a covering problem. Such problems are characterized by a constraint matrix that has in every column blocks of consecutive ones, each corresponding to a shift. We focus on three type of shift scheduling problems classified according to the column structure in the constraint matrix: consecutive ones columns, cyclical ones columns and k...