Continuous-Time Quantum Walks on Directed Bipartite Graphs

This paper investigates continuous-time quantum walks on directed bipartite graphs based on a graph's adjacency matrix. We prove that on bipartite graphs, probability transport between the two node partitions can be completely suppressed by tuning a model parameter $\alpha$. We provide analytic solutions to the quantum walks for the star and circulant graph classes that are valid for an arbitrary value of the number of nodes $N$, time $t$ and the model parameter $\alpha$. We discuss quantitative and qualitative aspects of quantum walks based on directed graphs and their undirected counterparts. Numerical simulations of quantum walks on circulant graphs show complex interference phenomena and how complete suppression of transport is achieved near $\alpha=\pi/2$. By proving two mirror symmetries around $\alpha=0$ and $\pi/2$ we show that these quantum walks have a period of $\pi$ in $\alpha$. We show that undirected edges lose their effect on the quantum walk at $\alpha=\pi/2$ and present non-bipartite graphs that exhibit suppression of transport. Finally, we analytically compute the Hamiltonians of quantum walks on the directed ring graph.Comment: 10 pages, 3 figure

Suitability of a CMV/EGFP cassette to monitor stable expression from human artificial chromosomes but not transient transfer in the cells forming viable clones

Human artificial chromosomes (HACs) were generated by transfer of telomerized PAC constructs containing alpha satellite DNA of various human chromosomes. To monitor which cells took up constructs and subsequently formed stable clones under blasticidin S (BS) selection, a CMV/EGFP expression cassette was inserted into a HAC construct based on chromosome 5 alpha satellite DNA (142 kb). Lipofection into HT1080 cells resulted in a small proportion of cells exhibiting bright green fluorescence on day 1. Areas containing such early green cells were marked, and plates monitored over 2 weeks. In only one out of 41 marked areas, a viable clone developed. In the remaining 40 areas, the green cells ceased division at 1-8 cells. In contrast, outside the marked areas, 16 stable clones formed which did not exhibit green fluorescence during the first cell divisions, but all cells of each became green around day 4 -6. Fluorescence in situ hybridization (FISH) analysis of isolated clonal lines demonstrated low copy HAC formation without integration. We conclude that transient expression of an EGFP marker on HAC DNA is not a suitable means for the identification of the proportion of transfected cells which are capable of forming viable clones. One explanation could be that the high copy number required to consistently detect transient EGFP expression (Schindelhauer and Laner, 2002) impairs viability and clone formation. Copyright (C) 2004 S. Karger AG, Basel

Run 2 Upgrades to the CMS Level-1 Calorimeter Trigger

The CMS Level-1 calorimeter trigger is being upgraded in two stages to maintain performance as the LHC increases pile-up and instantaneous luminosity in its second run. In the first stage, improved algorithms including event-by-event pile-up corrections are used. New algorithms for heavy ion running have also been developed. In the second stage, higher granularity inputs and a time-multiplexed approach allow for improved position and energy resolution. Data processing in both stages of the upgrade is performed with new, Xilinx Virtex-7 based AMC cards.Comment: 10 pages, 7 figure

Caring critique. Exploring pedagogical spheres between critical and post-critical approaches

Preservation, positive affection, hope and experience are some of the core concerns of post-critical pedagogy. In order to highlight them, post-critical approaches regard it as necessary to refuse critical action on the one hand and separate the pedagogical from the political sphere on the other. In his paper the author will suggest that there is a possibility to stress post-critical ideas and the need to rethink what pedagogical thinking and action is about without abandoning the critical attitude and the orientation towards the political. This possibility is bound to an inverse perspective on critique and politics. In this inverse view, which the author develops engaging with recent debates in critical theory, critique can be framed as a situated engagement that faces the other within a lively present experience. Politics can be understood as variable forms of living together with humans and non-humans on the basis of shared times and spaces. Bringing in this perspective, makes it possible to go beyond the critique-post-critique-struggle and introduce an approach that is sympathetic with both critical and post-critical concerns. (DIPF/Orig.

Knowledge base to facilitate anthropogenic resource assessment

Non-energy mineral resources such as iron and ferro-alloy metals, non-ferrous metals, precious metals, industrial minerals and construction materials are essential for industrial production, the prosperity of nations and modern living standards