A-optimal designs for an additive quadratic mixture model

Quadratic models are widely used in the analysis of experiments involving mixtures. This paper gives A-optimal designs for an additive quadratic mixture model for q ≥ 3 mixture components. It is proved that in these A-optimal designs, vertices of the simplex S q-1 are support points, and other support points shift gradually from barycentres of depth 1 to barycentres of depth 3 as q increases. A-optimal designs with minimal support are also discussed.published_or_final_versio

Effect of a point impurity on the vortex bound states in an s-wave superconductor: A self-consistent analysis

On the basis of self-consistent numerical solution of the Bogoliubov-de Gennes equations on a finite-size lattice, we study the variation of the vortex bound state when an impurity potential is added to the core of an isolated vortex line in an s-wave superconductor. The local density of states is investigated at both the core and its neighbor site. By analyzing the impurity-induced increase of the pair potential near the vortex core, we elucidate the mechanism of the vortex pinning in detail.published_or_final_versio

Electronic structure of the vortex lattice of d-, d+is-, and dx2-y2+idxy-wave superconductors

On the basis of the self-consistent Bogoliubov-de Gennes equations and a tight-binding lattice model, we investigate the quasiparticle spectrum of vortex-lattice state in pure d-, mixed d+is, and dx2-y2+idxy-wave superconductors. For a d-wave case, the local density of states (LDOS) at the vortex core shows a multipeak structure, and the positions of peaks as well as the width of splitting between peaks are sensitively dependent on both the magnetic-field strength and the orientation of the vortex lattice. For the mixed d+is- and dx2-y2+idxy-wave pairing states, we observe a double-peak structure of the local density of states at vortex center, where the two peaks are asymmetrically situated around the Fermi energy. By taking into account the matrix-element effect, the local density of states appears to be qualitatively consistent with the scanning-tunneling-microscopy experimental data.published_or_final_versio

Analysis on the critical factors of over-time and over-pay problems for government engineering project construction

2007-2008 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Design of 2D Time-Varying Vector Fields

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Construction and Control of Genetic Regulatory Networks: A Multivariate Markov Chain Approach

In the post-genomic era, the construction and control of genetic regulatory networks using gene expression data is a hot research topic. Boolean networks (BNs) and its extension Probabilistic Boolean Networks (PBNs) have been served as an effective tool for this purpose. However, PBNs are difficult to be used in practice when the number of genes is large because of the huge computational cost. In this paper, we propose a simplified multivariate Markov model for approximating a PBN The new model can preserve the strength of PBNs, the ability to capture the inter-dependence of the genes in the network, qnd at the same time reduce the complexity of the network and therefore the computational cost. We then present an optimal control model with hard constraints for the purpose of control/intervention of a genetic regulatory network. Numerical experimental examples based on the yeast data are given to demonstrate the effectiveness of our proposed model and control policy.published_or_final_versio

Optimal designs for an additive quadratic mixture model involving the amount of mixture

This paper is concerned with D- and A-optimal designs for a quadratic additive model for experiments with mixtures, in which the response depends not only on the relative proportions but also on the actual amounts of the mixture components. It is found that the origin and vertices of the simplex are support points of these optimal designs, and when the number of mixture components increases, other support points shift gradually from barycentres of depth 1 to barycentres of higher depths. It is shown that the D-optimal designs have high efficiency in terms of A-optimality, and vice versa.published_or_final_versio

Women’s beliefs about the duration of pregnancy and the earliest gestational age to safely give birth.

Background: American evidence suggests women are not well informed about the optimal duration of pregnancy or the earliest time for safe birth. Similar evidence does not exist in Australia. Aims: To explore pregnant women’s beliefs about the duration of pregnancy and the earliest time for safe birth, and to compare the results with US data. Methods: A cross-sectional survey of pregnant women attending antenatal clinics at four public hospitals in Sydney, Australia, included collection of maternal and pregnancy characteristics, and two questions exploring women’s beliefs about the duration of pregnancy, and the earliest time for safe birth. Responses were grouped as: late preterm (34-36 weeks), early term (37-38 weeks), and full term (39-40 weeks). Results: Of 784 surveyed women, 52% chose 39-40 weeks as the duration of a full term pregnancy, while for the earliest time for safe birth, 10% chose 39-40 weeks and 57% chose 37-38 weeks. Some maternal characteristics were associated with women’s beliefs, including having a medical and/or pregnancy complication, country of birth, level of education, employment status, and attending a tertiary hospital. The associations were different for each question. In comparison with US studies, Australian women were more likely to choose later gestations for both the duration of pregnancy and the earliest time for safe birth. Conclusions: A significant proportion of Australian women believe that full term pregnancy and earliest time for safe birth occur before 39 weeks, suggesting opportunities for antenatal education.The authors would like to thank the women who participated in the survey, and acknowledge the contribution of the research midwives, Jill Milligan, Rachel Reid, Jocelyn Sedgley and Katrina White-Mathews, as well as Dr. Antonia Shand for assisting with participant recruitment. This work was supported by an Australian National Health and Medical Research Council (NHMRC) Centre for Research Excellence Grant (1001066). CLR is supported by an NHMRC Senior Research Fellowship (#APP1021025)

Genetic diversity among natural populations of Ottelia acuminata (Gaghep.) Dandy revealed by ISSR

Ottelia acuminata (Gagnep.) Dandy, an aquatic species of the Hydrocharitaceae, is endemic to China. A performance comparison of genetic diversity of 4 natural populations was conducted to investigatewhether or not water pollution in their habitats has anything to do with this species being endangered. A total number of 120 O. acuminate accessions were analyzed, by amplification of their DNAs with 15 primers (ISSR). Thirteen primers were scored and 214 bands were detected, of which 170 werepolymorphic (79.44%). The results showed that the genetic indices in polluted Jian Lake group were always the smallest ones, when compared with those of the other groups. It indicated that the polluted water did affect the genetic diversity of O. acuminate populations. And ISSRs seemed to be effectivetools for detecting genetic variation among O. acuminate geographical groups