Bacterial chemotaxis without gradient-sensing

Models for chemotaxis are based on gradient sensing of individual organisms. The key contribution of Keller and Segel is showing that erratic movements of individuals may result in an accurate chemotaxis phenomenon as a group. In this paper we provide another option to understand chemotactic behavior when individuals do not sense the gradient of chemical concentration by any means. We show that, if individuals increase their motility to find food when they are hungry, an accurate chemotactic behavior may obtained without sensing the gradient. Such a random dispersal has been suggested by Cho and Kim and is called starvation driven diffusion. This model is surprisingly similar to the original derivation of Keller-Segel model. A comprehensive picture of traveling band and front solutions is provided with numerical simulations.Comment: 19 pages, 4 figure

The factors influencing a contract payment structure in biotech licensing deals

Department of Management EngineeringThere are many studies which try to identify and verify theoretically and empirically many factors influencing technology market???s elements including rate of technology licensing, informational asymmetry, pricing of technology and so forth. In this study, based on conventional bargaining power???s approach and signaling theory???s perspective, I identified and verified empirically a couple of determinants influencing contract payment structure of licensing. Licensor???s size and licensee???s size has a positive impact on a share of fixed upfront payment in contract payment structure. Licensed technology???s development phase has a positive impact on a share of fixed upfront payment in contract payment structure and licensing region has a negative impact on a share of fixed upfront payment in contract payment structure. There is significant moderation of technology development phase on direct effect of licensor???s size and leverage on contact payment structure. Generally, in biotechnology industry, conventional bargaining power???s approach is dominant over signaling theory???s perspective. Total asset as a proxy for size is justified empirically compared to other size measures such as total revenue.ope

Hodge ideals and spectrum of isolated hypersurface singularities

We introduce Hodge ideal spectrum for isolated hypersurface singularities to see the difference between the Hodge ideals and the microlocal $V$-filtration modulo the Jacobian ideal. Via the Tjurina subspectrum, we can compare the Hodge ideal spectrum with the Steenbrink spectrum which can be defined by the microlocal $V$-filtration. As a consequence of a formula of Mustata and Popa, these two spectra coincide in the weighted homogeneous case. We prove sufficient conditions for their coincidence and non-coincidence in some non-weighted-homogeneous cases where the defining function is semi-weighted-homogeneous or with non-degenerate Newton boundary in most cases. We also show that the convenience condition can be avoided in a formula of Zhang for the non-degenerate case, and present an example where the Hodge ideals are not weakly decreasing even modulo the Jacobian ideal.Comment: 29 page

Investigating Factors Affecting Electronic Word-Of-Mouth In The Open Market Context: A Mixed Methods Approach

Electronic Word-of-Mouth (eWOM) has been identified as one of key factors affecting online sales. There has been, however, lack of understanding about the factors leading to eWOM in the open market context. As many Internet vendors have adopted the open market business, it is essential to understand the factors leading to eWOM for the success of open market business. This study investigates factors affecting eWOM in the open market context based on a sequential combination of qualitative and quantitative research methods. The exploratory findings in the qualitative study become the basis for the quantitative study, survey research. The findings from the mixed methods explain the significance of three new factors (information sharing desire, self-presentation desire, and open market reward) and two other factors (open market satisfaction and open market loyalty) affecting eWOM directly and indirectly. This study contributes to research by adding to the broader literature on eWOM. The findings also can inform open market providers on how to promote and manage eWOM for their online business success