Paracoccus sp. Strain LL1 as a Single Cell Factory for the Conversion of Waste Cooking Oil to Polyhydroxyalkanoates and Carotenoids

Background and objective: Polyhydroxyalkanoates have drawn significant attention as alternative to petroleum-based plastics; however, their industrial production is still hindered by the costly feed materials. Co-generation of other high-value products in addition to polyhydroxyalkanoate by the same microbial strains can be helpful in alleviating overall production cost up to 50%. This study for the first time demonstrates that polyhydroxyalkanoate and astaxanthin-rich carotenoids can be co-produced by Paracoccus sp. LL1 using waste cooking oil as substrate.Material and methods: The halophilic strain of Paracoccus sp. LL1 was grown under batch fermentation using mineral media supplemented with 1% (v v-1) waste cooking oil. Different surfactants were used to improve substrate utilization. Polyhydroxyalkanoate obtained after the fermentation was characterized by fluorescent microscopy, gas chromatography, and Fourier Transform Infra-Red spectroscopy.Results and conclusion: Oil as a substrate, led to 1.0 g l-1 poly (3-hydroxybutyrate-co-3-hydroxyvalerate) with concomitant production of 0.89 mg l-1 of carotenoids after 96 h. An enhancement of 2.7-folds in total cell dry mass was achieved when 0.1% (v v-1) Tween-80 was used as surfactant for ease in oil metabolism. Paracoccus sp. LL1 has the potential to serve as a single cell factory for bioconversion of cheap substrates into high value products.Conflict of interest: The authors declare no conflict of interest

CRM Strategies for A Small-Sized Online Shopping Mall Based on Association Rules and Sequential Patterns

Data mining has a tremendous contribution to the extraction of knowledge and information which have been hidden in a large volume of data. This study has proposed customer relationship management (CRM) strategies for a small-sized online shopping mall based on association rules and sequential patterns obtained by analyzing the transaction data of the shop. We first defined the VIP customer in terms of recency, frequency and monetary value. Then, we developed a model which classifies customers into VIP or non-VIP, using various techniques such as decision tree, artificial neural network and bagging with each of these as a base classifier. Last, we identified association rules and sequential patterns from the transactions of VIPs, and then these rules and patterns were utilized to propose CRM strategies for the online shopping mall

Critical currents for vortex defect motion in superconducting arrays

We study numerically the motion of vortices in two-dimensional arrays of resistively shunted Josephson junctions. An extra vortex is created in the ground states by introducing novel boundary conditions and made mobile by applying external currents. We then measure critical currents and the corresponding pinning energy barriers to vortex motion, which in the unfrustrated case agree well with previous theoretical and experimental findings. In the fully frustrated case our results also give good agreement with experimental ones, in sharp contrast with the existing theoretical prediction. A physical explanation is provided in relation with the vortex motion observed in simulations.Comment: To appear in Physical Review

Vip-Focused Crm Strategies In An Open-Market

Nowadays, an open-market which provides sellers and consumers a cyber place for making a transaction over the Internet has emerged as a prevalent sales channel because of convenience and relatively low price it provides. However, there are few studies about CRM strategies based on VIP consumers for an open-market even though understanding VIP consumers’ behaviours in an open-market is absolutely important to increase its revenue. Therefore, we propose CRM strategies focused on VIP customers, obtained by analyzing the transaction data of VIP customers from an open-market using data mining techniques. To that end, we first defined the VIP customers in terms of recency, frequency and monetary (RFM) values. Then, we used data mining techniques to develop a model which best classifies customers into VIPs or non-VIPs. We also validate each of promotion types in the aspect of effectiveness to VIP customers and identify association rules among the types from the transactions of VIP customers. Then, based on the findings from these experiments, we propose strategies from the perspectives of CRM dimensions such as customer identification, attraction, retention and development for the open-market to thrive

Spatiotemporal Stochastic Resonance in Fully Frustrated Josephson Ladders

We consider a Josephson-junction ladder in an external magnetic field with half flux quantum per plaquette. When driven by external currents, periodic in time and staggered in space, such a fully frustrated system is found to display spatiotemporal stochastic resonance under the influence of thermal noise. Such resonance behavior is investigated both numerically and analytically, which reveals significant effects of anisotropy and yields rich physics.Comment: 8 pages in two columns, 8 figures, to appear in Phys. Rev.

Dynamic transition and Shapiro-step melting in a frustrated Josephson-junction array

We consider a two-dimensional fully frustrated Josephson-junction array driven by combined direct and alternating currents. Interplay between the mode locking phenomenon, manifested by giant Shapiro steps in the current-voltage characteristics, and the dynamic phase transition is investigated at finite temperatures. Melting of Shapiro steps due to thermal fluctuations is shown to be accompanied by the dynamic phase transition, the universality class of which is also discussed