Internal Diffusion-Limited Aggregation: Parallel Algorithms and Complexity

The computational complexity of internal diffusion-limited aggregation (DLA) is examined from both a theoretical and a practical point of view. We show that for two or more dimensions, the problem of predicting the cluster from a given set of paths is complete for the complexity class CC, the subset of P characterized by circuits composed of comparator gates. CC-completeness is believed to imply that, in the worst case, growing a cluster of size n requires polynomial time in n even on a parallel computer. A parallel relaxation algorithm is presented that uses the fact that clusters are nearly spherical to guess the cluster from a given set of paths, and then corrects defects in the guessed cluster through a non-local annihilation process. The parallel running time of the relaxation algorithm for two-dimensional internal DLA is studied by simulating it on a serial computer. The numerical results are compatible with a running time that is either polylogarithmic in n or a small power of n. Thus the computational resources needed to grow large clusters are significantly less on average than the worst-case analysis would suggest. For a parallel machine with k processors, we show that random clusters in d dimensions can be generated in O((n/k + log k) n^{2/d}) steps. This is a significant speedup over explicit sequential simulation, which takes O(n^{1+2/d}) time on average. Finally, we show that in one dimension internal DLA can be predicted in O(log n) parallel time, and so is in the complexity class NC

Rich States, Poor States: ALEC-Laffer State Economic Competitiveness Index

Ranks states' business climates based on income, population growth, and employment and outlook based on current tax policies; analyzes their fiscal conditions; reviews 2010 fiscal reform initiatives; and recommends policies to spur economic growth

A Dichotomy Theorem for Circular Colouring Reconfiguration

The "reconfiguration problem" for circular colourings asks, given two $(p,q)$-colourings $f$ and $g$ of a graph $G$, is it possible to transform $f$ into $g$ by changing the colour of one vertex at a time such that every intermediate mapping is a $(p,q)$-colouring? We show that this problem can be solved in polynomial time for $2\leq p/q <4$ and is PSPACE-complete for $p/q\geq 4$. This generalizes a known dichotomy theorem for reconfiguring classical graph colourings.Comment: 22 pages, 5 figure

MCMC-ODPR : primer design optimization using Markov Chain Monte Carlo sampling

Background Next generation sequencing technologies often require numerous primer designs that require good target coverage that can be financially costly. We aimed to develop a system that would implement primer reuse to design degenerate primers that could be designed around SNPs, thus find the fewest necessary primers and the lowest cost whilst maintaining an acceptable coverage and provide a cost effective solution. We have implemented Metropolis-Hastings Markov Chain Monte Carlo for optimizing primer reuse. We call it the Markov Chain Monte Carlo Optimized Degenerate Primer Reuse (MCMC-ODPR) algorithm. Results After repeating the program 1020 times to assess the variance, an average of 17.14% fewer primers were found to be necessary using MCMC-ODPR for an equivalent coverage without implementing primer reuse. The algorithm was able to reuse primers up to five times. We compared MCMC-ODPR with single sequence primer design programs Primer3 and Primer-BLAST and achieved a lower primer cost per amplicon base covered of 0.21 and 0.19 and 0.18 primer nucleotides on three separate gene sequences, respectively. With multiple sequences, MCMC-ODPR achieved a lower cost per base covered of 0.19 than programs BatchPrimer3 and PAMPS, which achieved 0.25 and 0.64 primer nucleotides, respectively. Conclusions MCMC-ODPR is a useful tool for designing primers at various melting temperatures at good target coverage. By combining degeneracy with optimal primer reuse the user may increase coverage of sequences amplified by the designed primers at significantly lower costs. Our analyses showed that overall MCMC-ODPR outperformed the other primer-design programs in our study in terms of cost per covered base

Saving Souls and Securing the Socioeconomic Status Quo: A Consideration of Billy Sunday and the Pacific Garden Mission

With these words, professional baseball player-turned-evangelist Billy Sunday placed himself outside the mainstream of middle-class America\u27s growing urban culture. However, as historian Laurence Moore notes, outsiderhood is a characteristic way of inventing one\u27s Americanness. Indeed, as Sunday\u27s fiery blend of evangelism and vaudeville antics reached into the furthest recesses of the nation\u27s religious consciousness, the revivalist found himself at the forefront of the early twentieth century fundamentalist movement. Emerging from his conversion at Chicago\u27s Pacific Garden Mission, Sunday attained the pinnacle of his success between 1908 and 1920. Little interested in developing a comprehensive theology, both Sunday and Pacific Garden Mission came to perceive themselves as metaphorical lighthouses, moral beacons that could lead sinners through the turbulent seas of sin to safe harbor In Jesus Christ. Despite attempting to address social ills through evangelism, the message of Sunday and the Mission tacitly endorsed the socioeconomic status quo by overwhelmingly emphasizing personal spiritual conversion as the sole means of meaningful reform

An Investigation into the Relationship Between the Subjective Descriptor Aggressive and the Universal Audio 1176 FET Compressor

In popular music productions, the lead vocal is often the main focus of the mix and engineers will work hard to impart creative colouration on this source. This paper conducts listening experiments to test if there is a correlation between perceived distortion and the descriptor “aggressive” which is often used to describe the sonic signature of the Universal Audio 1176. The results from this study show compression settings that impart audible distortion are perceived as aggressive by the listener and. Furthermore, there is a strong correlation between the subjective scores for distortion and aggressive. eIt was also shown that there is a strong correlation between compression settings measured rated to have 0.5% THD and above were rated as both the most distorted and most aggressive. high aggressive scores and the audio feature roughness