Factors contributing to biofilm formation of Yersinia enterocolitica : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology, Massey University, Palmerston North, New Zealand

Content removed from thesis due to copyright reasons: Wang H., Palmer J., & Flint S. (2015). A rapid method for the nonselective enumeration of Yersinia enterocolitica, a foodborne pathogen associated with pork. Meat Science, 113: 59–61. doi:10.1016/j.meatsci.2015.11.005; Wang H., Tay M., Palmer J., Flint S. (2016) Biofilm formation of Yersinia enterocolitica and its persistence following treatment with different sanitation agents. Food Control, 73, 433-437. doi:10.1016/j.foodcont.2016.08.033Biofilms of pathogenic bacteria are recognised as a threat to food safety. The aim of the present study was to investigate the potential of Yersinia enterocolitica to form biofilms in the pork processing environment and identify the resistance of these biofilms to sanitation. The biofilm formation by Y. enterocolitica was monitored at conditions simulating pork processing environment under daily cleaning routine using an impedance method established in this study. Results showed that Y. enterocolitica had the potential to form biofilm and become resistant to sanitation in a pork processing environment. An investigation into the factors influencing biofilm formation of Y. enterocolitica indicated that the Ca2+ ion increased the level of biofilm formation. In addition, the presence of the virulence plasmid pYV is essential for the biofilm Ca2+ response. Further analysis of the bacterial cell surface properties and extracellular polymeric substance (EPS) composition suggested that the pYV+ cell surfaces are more negatively charged and more hydrophobic than the pYV- cells although no significant difference was observed with the addition of Ca2+. The pYV+ cells appear to produce more exopolysaccharide than the pYV- cells regardless of Ca2+ concentration. Ca2+ was able to increase the yield of extracellular DNA while the presence of pYV appeared to be dispensable in terms of extracellular DNA release. Analysis of cell wall protein revealed one protein expressed in the pYV+ cells but absent in the pYV- cells

Sense, Model and Identify the Load Signatures of HVAC Systems in Metro Stations

The HVAC systems in subway stations are energy consuming giants, each of which may consume over 10, 000 Kilowatts per day for cooling and ventilation. To save energy for the HVAC systems, it is critically important to firstly know the "load signatures" of the HVAC system, i.e., the quantity of heat imported from the outdoor environments and by the passengers respectively in different periods of a day, which will significantly benefit the design of control policies. In this paper, we present a novel sensing and learning approach to identify the load signature of the HVAC system in the subway stations. In particular, sensors and smart meters were deployed to monitor the indoor, outdoor temperatures, and the energy consumptions of the HVAC system in real-time. The number of passengers was counted by the ticket checking system. At the same time, the cooling supply provided by the HVAC system was inferred via the energy consumption logs of the HVAC system. Since the indoor temperature variations are driven by the difference of the loads and the cooling supply, linear regression model was proposed for the load signature, whose coefficients are derived via a proposed algorithm . We collected real sensing data and energy log data from HaiDianHuangZhuang Subway station, which is in line 4 of Beijing from the duration of July 2012 to Sept. 2012. The data was used to evaluate the coefficients of the regression model. The experiment results show typical variation signatures of the loads from the passengers and from the outdoor environments respectively, which provide important contexts for smart control policies.Comment: 5 pages, 5 figure

L'espace sym\'etrique de Drinfeld et correspondance de Langlands locale I

Let $K$ be a finite extension of $\mathbb{Q}_p$. We study the geometry and cohomology of the tamely ramified cover of Drinfeld's symmetric space over $K.$ We prove, in a purely local way, that the cohomology in middle degree realises the local Langlands correspondence and local Jacquet-Langlands correspondence for the depth zero supercuspidal representations.Comment: in Frenc

Improved time-decay for a class of many-magnetic Schr\"odinger flows

Consider the doubled magnetic Schr\"odinger operator \begin{equation*} H_{\alpha,B_0}=\left(i\nabla-\left(\frac{B_0|x|}{2}+\frac{\alpha}{|x|}\right)\left(-\frac{x_2}{|x|},\frac{x_1}{|x|}\right)\right)^2,\quad x=(x_1,x_2)\in\R^2\setminus\{0\}, \end{equation*} where $\frac{B_0|x|}{2}\left(-\frac{x_2}{|x|},\frac{x_1}{|x|}\right)$ stands for the homogeneous magnetic potential with $B_0>0$ and $\frac{\alpha}{|x|}\left(-\frac{x_2}{|x|},\frac{x_1}{|x|}\right)$ is the well-known Aharonov-Bohm potential with $\alpha\in\R\setminus\mathbb{Z}$. In this note, we obtain an improved time-decay estimate for the Schr\"odinger flow $e^{-itH_{\alpha,B_0}}$. The key ingredient is the dispersive estimate for $e^{-itH_{\alpha,B_0}}$, which was established in \cite{WZZ23} recently. This work is motivated by L. Fanelli, G. Grillo and H. Kova\v{r}\'{\i}k \cite{FGK15} dealing with the scaling-critical electromagnetic potentials in two and higher dimensions.Comment: 11pages,no figures,to appear in JMA