Expanding (3+1)-dimensional universe from a Lorentzian matrix model for superstring theory in (9+1)-dimensions

We reconsider the matrix model formulation of type IIB superstring theory in (9+1)-dimensional space-time. Unlike the previous proposal in which the Wick rotation was used to make the model well-defined, we regularize the Lorentzian model by introducing infrared cutoffs in both the spatial and temporal directions. Monte Carlo studies reveal that the two cutoffs can be removed in the large-N limit and that the theory thus obtained has no parameters other than one scale parameter. Moreover, we find that three out of nine spatial directions start to expand at some "critical time", after which the space has SO(3) symmetry instead of SO(9).Comment: 4 pages, 3 figures; minor corrections, reference added; improved discussions, the version published in PR

Evaluation of a Microalgal Bioassay Based on Community Level Physiological Profiling (CLPP)

This thesis examined the use of commercially available Biolog 96-well plates containing different carbon sources for a microalgal bioassay. Quaternary ammonium compounds (QACs) were used as potentially toxic model compounds to demonstrate the applicability of the assay. Toxicity of dodecyl trimethyl ammonium chloride (DTAC) and didecyl dimethyl ammonium bromide (DDAB) on the growth of Scenedesmus obliquus varied significantly under autotrophic, heterotrophic and mixotrophic growth conditions. The concentration for 50% growth inhibition effect (EC50) of DTAC followed the order: autotrophic (0.48 ± 0.03 mg of DTAC/L) \u3e heterotrophic (1.46 ± 0.04 mg of DTAC/L) \u3e mixotrophic (2.11 ± 0.06 mg of DTAC/L), whereas for DDAB, the order of inhibition was different as: heterotrophic (0.52 ± 0.02 mg of DDAB/L) \u3e autotrophic (1.18 ± 0.08 mg of DDAB/L) \u3e mixotrophic (1.35 ± 0.02 mg of DDAB/L). Moreover, EC50 values were a function of carbon source and growth regime, showing that only EC­50 values do not fully capture the toxic effects of a potentially toxic compound might have on algal communities. Therefore, a new assay was developed based on community level physiological profiling (CLPP). Five different mixtures of artificially defined microalgal communities were employed and the changes in substrate utilization patterns by the treatment of hexadecyl trimethyl ammonium chloride (CTAC) were quantified using principal component analysis (PCA). The toxic effect of CTAC was significant (P \u3c 0.05), showing 58% inhibition compared to the control and the effect was more pronounced for the treatment than that obtained by varying the initial composition of the defined algal communities. The newly developed assay was further applied on wetland water samples, wastewaters (i.e. primary and secondary), river water, and activated carbon treated and untreated oil sand process waters (OSPWs). The assay was able to generate a distinguishable response among these samples, measuring small differences within the respective water groups and larger differences between them

Percolation properties of growing networks under an Achlioptas process

We study the percolation transition in growing networks under an Achlioptas process (AP). At each time step, a node is added in the network and, with the probability $\delta$, a link is formed between two nodes chosen by an AP. We find that there occurs the percolation transition with varying $\delta$ and the critical point $\delta_c=0.5149(1)$ is determined from the power-law behavior of order parameter and the crossing of the fourth-order cumulant at the critical point, also confirmed by the movement of the peak positions of the second largest cluster size to the $\delta_c$. Using the finite-size scaling analysis, we get $\beta/\bar{\nu}=0.20(1)$ and $1/\bar{\nu}=0.40(1)$, which implies $\beta \approx 1/2$ and $\bar{\nu} \approx 5/2$. The Fisher exponent $\tau = 2.24(1)$ for the cluster size distribution is obtained and shown to satisfy the hyperscaling relation.Comment: 4 pages, 5 figures, 1 table, journal submitte

Thriving in the Political Sport Arena: LMX as a Mediator of the Political Skill– Career Success Relationship

Organizational politics, be it in sport organizations or other business contexts, is an unavoidable aspect of work and life. Further, some individuals are better than others at navigating the political arena and advancing their careers. It is therefore important to understand what characteristics those individuals possess and how exactly those characteristics lead to desirable career outcomes. This study progresses the organizational behavioral sciences forward by examining the mediation effects of leader-member exchange (LMX) in the relationships between intern political skill and four career-related outcomes (career satisfaction, perceived external marketability, life satisfaction, and perceived effectiveness). A total of 201 sport management student subjects were obtained. A boot-strapping method estimated with structural equation modeling (SEM) was used to test the mediation effects. The results of the study show that all the hypothesized mediation effects were indeed supported. Therefore, we concluded that the mediated paths of political skill through LMX to support career-success outcomes were supported. These results will hopefully stimulate continued interest in the individual “skills” and intervening ways through which aspiring sport professionals can achieve success in their internships (and subsequent employment) and current sport professionals can attain beneficial career-related outcomes