Origenes Research Articles

A Gaze-Driven Evolutionary Algorithm to Study Aesthetic Evaluation of Visual Symmetry.

Empirical work has shown that people like visual symmetry. We used a gaze-driven evolutionary algorithm technique to answer three questions about symmetry preference. First, do people automatically evaluate symmetry without explicit instruction? Second, is perfect symmetry the best stimulus, or do people prefer a degree of imperfection? Third, does initial preference for symmetry diminish after familiarity sets in? Stimuli were generated as phenotypes from an algorithmic genotype, with genes for symmetry (coded as deviation from a symmetrical template, deviation–symmetry, DS gene) and orientation (0° to 90°, orientation, ORI gene). An eye tracker identified phenotypes that were good at attracting and retaining the gaze of the observer. Resulting fitness scores determined the genotypes that passed to the next generation. We recorded changes to the distribution of DS and ORI genes over 20 generations. When participants looked for symmetry, there was an increase in high-symmetry genes. When participants looked for the patterns they preferred, there was a smaller increase in symmetry, indicating that people tolerated some imperfection. Conversely, there was no increase in symmetry during free viewing, and no effect of familiarity or orientation. This work demonstrates the viability of the evolutionary algorithm approach as a quantitative measure of aesthetic preference.

Attenuation of porcine circovirus type-2b by replacement with the Rep gene of porcine circovirus type-1

Porcine circovirus type-2 (PCV2) is the primary causative agent of porcine circovirus-associated diseases and has 4 main ORFs, ORF1 (Rep gene), ORF2 (Cap gene), ORF3 within ORF1, and ORF4, which is overlapped with ORF3, and 1 origin (Ori) of replication located between ORF1 and ORF2. The chimeric PCV1-2, containing the PCV2 capsid, PCV1 rep, and Ori genes, is attenuated in pigs. In order to verify the role of the Rep gene or Ori in the virulence of PCV2, 3 chimeric viruses [PCV2b-Ori1 (PCV1 Ori gene cloned into the backbone of PCV2b), PCV2b-rep1 (PCV1 Rep gene cloned into the backbone of PCV2b), and PCV2b-rep1-Ori1 (PCV1 Rep and Ori genes cloned into the backbone of PCV2b)] and 2 wild-type recombinant PCV2b and PCV1 were constructed and identified. The experimental results in piglets showed that clinical symptoms, viremia, viral load, lesions in lymphoid and lung tissues, and IL-10 and TNF-α expression levels in PBMCs in the PCV2b-rep1-Ori1 and PCV2b-rep1 groups were significantly decreased, compared to PCV2-infected piglets. Meanwhile, histological lesions of lymphoid and lung tissues, viral loads in lymphoid tissues, viremia, and TNF-α expression in PBMCs were not significantly different between groups PCV2b-Ori1 and PCV2b, suggesting that the Rep gene (ORF1) likely contributes to viral pathogenicity in vivo.

MORS PHILOSOPHI : THE DEATH OF JESUS IN LUKE

The death of Jesus of Nazareth by crucifixion was the source of numerous difficulties for early proponents of Christianity. Paul's statement to the Corinthians, “We preach Christ crucified, to the Jews a cause of offense and to the Gentiles foolishness” (1 Cor 1:23), was not hyperbolic rhetoric, but a sober assessment of the difficulty of proclaiming a condemned criminal to be the “Lord of glory” (1 Cor 2:8). The fundamental problem is obvious: a crucified Lord struck most ancients as an oxymoron.Early Christian authors were keenly aware of the negative associations of the cross; see Justin, 1 Apol. 13.4; Origen, Cels. 6.10; Lactantius, Inst. 4.26 and Epit. 50–51. The gospels did little to overcome the problem from a pagan perspective; in some cases they even exacerbated it. For example, Celsus, the learned and perceptive second-century critic of Christianity, found that the manner in which the evangelists described Jesus as he faced death undermined Christian claims for him. He wrote: “Why does he howl, lament, and pray to escape the fear of destruction, expressing himself in a manner like this: ‘Oh Father, if it be possible, let this cup pass’?”Origen, Cels. 6.10. Origen countered by pointing out that Celsus had doctored the texts by adding “lament” and omitting the all-important qualifying clause that demonstrates Jesus' voluntary obedience to the Father, “nevertheless, not as I will, but as you will.”Origen, Cels. 2.24. All translations are my own. I have used the edition of Paul B. Koetschau, Origenes Werke 1 (GCS; Leipzig: J. C. Hinrichs, 1899). However, he found it difficult to offer much more of a rebuttal and was forced to conclude: “But these matters, which require extended discussion by the wisdom of God, and which may reasonably be considered by those whom Paul calls ‘perfect’ …we, for the present, pass by …”Ibid.

Role of homology and pathway specificity for recombination between plasmids and bacteriophage lambda.

To determine the minimum amount of homology required for efficient recombination in Escherichia coli, we measured recombination frequencies between bacteriophage lambda and pBR322 derivatives containing lambda DNA fragments of various sizes by assaying for phages that could transduce the bla and ori genes of pBR322. Efficient recombination required about 40 bp of homology; increases in homology above 40 bp resulted in proportionate increases in recombination, while decreases below 40 bp resulted in precipitous decreases in recombination. The recA+ gene stimulated recombination over the entire range of homologies tested. Restriction enzyme digests of several recombinant DNA molecules indicated that they contained the complete plasmid DNA inserted in the lambda genome as expected for a reciprocal crossover. Analysis of recombination frequencies in different recombination-deficient mutant strains indicated that the formation of lambda-plasmid cointegrates by homologous recombination proceeded predominantly by the RecBC pathway and very inefficiently, if at all, by the RecE and RecF pathways.