In 1989, B. Greene, a postdoc of Yau at the time, and R. Plesser constructed an important example of mirror manifolds. Using physics argument, they proved the first case of mirror symmetry for Calabi-Yau threefolds. Their result is considered fundamental, though its proof lacks the precision of a mathematical proof, hence the result does not constitute a mathematical theorem. Two years later, C...

‘‘The whole organism is so tied together that when slight variations in one part occur, and are accumulated through natural selection, other parts become modified. This is a very important subject, most imperfectly understood.’’ (Darwin, 1859, The Origin of Species). ‘‘Hence if man goes on selecting, and thus augmenting, any peculiarity, he will almost certainly modify unintentionally other par...

Accommodating many users in a small area is a major issue in the communication system. Frequency spectrum sharing and time sharing are used in the conventional systems. Hence, they have limitation on the capacity of the system. With the advent of spread spectrum, many users can be accommodated within the fixed bandwidth by making use of certain coding properties over the bandwidth. However, thi...

The problem of on-line bin packing restricted to instances with only two item sizes (known in advance) has a well-known lower bound of 4/3 for its asymptotic competitive ratio. We present an algorithm which shows that this lower bound is also an upper bound. Hence the asymptotic competitive ratio for this on-line problem is equal to 4/3. Our result extends the corresponding result of Faigle, Ke...

This paper offers a rigorous step-by-step methodology for either developing or testing theories and contains specific and detailed guidelines for IS researchers to follow in carrying out positivist case studies. The methodology is largely inspired by the work of Yin (1994), Eisenhardt (1989), Miles and Huberman (1994) and several others who are strong proponents of and have wide experience in t...

This study investigated digital financial services and economic growth of Nigeria from 2006 to 2021. The specific objectives include investigation the relationship between automated teller machine real gross domestic product; evaluation point sales determination mobile banking web product 2021 in Nigeria. anchored on technology acceptance model (TAM) advanced by Davis (1989) purposive sampling ...

fuller, in 1989, described probiotic microorganisms as “a live microbial feed supplement,which beneficially affects the host animal, by improving its intestinal microbial balance”.saccharomyces cerevisiae var. boulardii (s.boulardii) is an accurate probiotic yeast idol.the detection and budding of s.boulardiiis firmly related to the impression of healthinessto promote microorganisms from foodst...

Chairman: 1989-93 D. E. Wells (UK); Secretaly: 1989-93 D. G. Westmoreland (USA); Titular Members: K. Biemann (USA; 1989-91); W. H. Gries (FRG; 1989-91); M. J.-F. Leroy (France; 1989-93); M. W. Linscheid (FRG; 1991-93); M. Morita (Japan; 1989-93); M. J. Pellin (USA; 1991-93); B. Ya. Spivakov (Russia; 1989-93); Associate Members: S . Caroli (Italy; 1991-93); W. P. Cofino (Netherlands; 1989-93); R...