5,404 research outputs found
Design degrees of freedom and mechanisms for complexity
We develop a discrete spectrum of percolation forest fire models characterized by increasing design degrees of freedom (DDOF’s). The DDOF’s are tuned to optimize the yield of trees after a single spark. In the limit of a single DDOF, the model is tuned to the critical density. Additional DDOF’s allow for increasingly refined spatial patterns, associated with the cellular structures seen in highly optimized tolerance (HOT). The spectrum of models provides a clear illustration of the contrast between criticality and HOT, as well as a concrete quantitative example of how a sequence of robustness tradeoffs naturally arises when increasingly complex systems are developed through additional layers of design. Such tradeoffs are familiar in engineering and biology and are a central aspect of the complex systems that can be characterized as HOT
Lord Dunsany and the Great War: \u3ci\u3eDon Rodriguez\u3c/i\u3e and the Rebirth of Romance
Considers Lord Dunsany’s response to the Great War and modernized conflict in general in Don Rodriguez. In a pivotal section of this Quixotic romantic adventure, the character of Rodriguez is shown visions of modern war that cause him to question not just his heroic warrior ideals, but the purpose of Creation itself; his following adventures are increasingly in the ironic mode. Rodriguez is able to transcend his experiences in the end
A molecular dynamics simulation of DNA damage induction by ionizing radiation
We present a multi-scale simulation of early stage of DNA damages by the
indirect action of hydroxyl (OH) free radicals generated by electrons
and protons. The computational method comprises of interfacing the Geant4-DNA
Monte Carlo with the ReaxFF molecular dynamics software. A clustering method
was employed to map the coordinates of OH-radicals extracted from the
ionization track-structures onto nano-meter simulation voxels filled with DNA
and water molecules. The molecular dynamics simulation provides the time
evolution and chemical reactions in individual simulation voxels as well as the
energy-landscape accounted for the DNA-OH chemical reaction that is
essential for the first principle enumeration of hydrogen abstractions,
chemical bond breaks, and DNA-lesions induced by collection of ions in clusters
less than the critical dimension which is approximately 2-3 \AA. We show that
the formation of broken bonds leads to DNA base and backbone damages that
collectively propagate to DNA single and double strand breaks. For illustration
of the methodology, we focused on particles with initial energy of 1 MeV. Our
studies reveal a qualitative difference in DNA damage induced by low energy
electrons and protons. Electrons mainly generate small pockets of
OH-radicals, randomly dispersed in the cell volume. In contrast,
protons generate larger clusters along a straight-line parallel to the
direction of the particle. The ratio of the total DNA double strand breaks
induced by a single proton and electron track is determined to be 4
in the linear scaling limit. The tool developed in this work can be used in the
future to investigate the relative biological effectiveness of light and heavy
ions that are used in radiotherapy.Comment: 7 pages, 7 figures, accepted for publication in Physics in Medicine
and Biolog
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Reflective Group Writing Project for ENG 3140
This assignment is a culminating group writing project/presentation for ENG 3140 Native American and Indigenous Literatures. Students are asked to assess the course content and pedagogy through two lenses: (1) theories regarding the nature of decolonizing pedagogy derived from the field of indigenous studies, and (2) CSUSBs specific GE Diversity and Inclusion and Global Perspectives designations. The goal is for students to assess whether the way our institution frames its GE ILOs is compatible with decolonial practice as defined within the field
Vertex and source determine the block variety of an indecomposable module
AbstractThe block variety VG,b(M) of a finitely generated indecomposable module M over the block algebra of a p-block b of a finite group G, introduced in (J. Algebra 215 (1999) 460), can be computed in terms of a vertex and a source of M. We use this to show that VG,b(M) is connected, and that every closed homogeneous subvariety of the affine variety VG,b defined by block cohomology H*(G,b) (cf. Algebras Rep. Theory 2 (1999) 107) is the variety of a module over the block algebra. This is analogous to the corresponding statements on Carlson's cohomology varieties in (Invent. Math. 77 (1984) 291)
The D=1 Matrix Model and the Renormalization Group
We compute the critical exponents of string theory to leading order,
using the renormalization group approach recently suggested by Br\'{e}zin and
Zinn-Justin.Comment: 8 pages, Latex, CERN-TH-6546/9
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