The structure of preserved information in quantum processes

We introduce a general operational characterization of information-preserving structures (IPS) -- encompassing noiseless subsystems, decoherence-free subspaces, pointer bases, and error-correcting codes -- by demonstrating that they are isometric to fixed points of unital quantum processes. Using this, we show that every IPS is a matrix algebra. We further establish a structure theorem for the fixed states and observables of an arbitrary process, which unifies the Schrodinger and Heisenberg pictures, places restrictions on physically allowed kinds of information, and provides an efficient algorithm for finding all noiseless and unitarily noiseless subsystems of the process

The electoral effectiveness of constituency campaigning in the 2010 British General Election: The ‘triumph’ of Labour?

This is the post-print version of the final paper published in Electoral Studies. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2011 Elsevier B.V.This article establishes a model of likely campaign effectiveness, before examining the intensity of constituency campaigning at the 2010 general election in Britain and its subsequent impact on electoral outcomes, using both aggregate and individual level data. It shows that constituency campaigning yielded benefits in varying degrees for all three main parties and that Labour’s constituency campaign efforts were effective despite the electoral context, and ultimately affected the overall outcome of the election. These findings have significant implications for our understanding of the circumstances under which campaigns are likely to be more or less effective, and provide further evidence that a carefully managed campaign stands the most chance of delivering tangible electoral payoffs

Quantum Error Correction of Observables

A formalism for quantum error correction based on operator algebras was introduced in [1] via consideration of the Heisenberg picture for quantum dynamics. The resulting theory allows for the correction of hybrid quantum-classical information and does not require an encoded state to be entirely in one of the corresponding subspaces or subsystems. Here, we provide detailed proofs for the results of [1], derive a number of new results, and we elucidate key points with expanded discussions. We also present several examples and indicate how the theory can be extended to operator spaces and general positive operator-valued measures.Comment: 22 pages, 1 figure, preprint versio

Relationship between Hexokinase and the Aquaporin PIP1 in the Regulation of Photosynthesis and Plant Growth

Increased expression of the aquaporin NtAQP1, which is known to function as a plasmalemma channel for CO2 and water, increases the rate of both photosynthesis and transpiration. In contrast, increased expression of Arabidopsis hexokinase1 (AtHXK1), a dual-function enzyme that mediates sugar sensing, decreases the expression of photosynthetic genes and the rate of transpiration and inhibits growth. Here, we show that AtHXK1 also decreases root and stem hydraulic conductivity and leaf mesophyll CO2 conductance (gm). Due to their opposite effects on plant development and physiology, we examined the relationship between NtAQP1 and AtHXK1 at the whole-plant level using transgenic tomato plants expressing both genes simultaneously. NtAQP1 significantly improved growth and increased the transpiration rates of AtHXK1-expressing plants. Reciprocal grafting experiments indicated that this complementation occurs when both genes are expressed simultaneously in the shoot. Yet, NtAQP1 had only a marginal effect on the hydraulic conductivity of the double-transgenic plants, suggesting that the complementary effect of NtAQP1 is unrelated to shoot water transport. Rather, NtAQP1 significantly increased leaf mesophyll CO2 conductance and enhanced the rate of photosynthesis, suggesting that NtAQP1 facilitated the growth of the double-transgenic plants by enhancing mesophyll conductance of CO2

An investigation of a mathematical model to characterize the nonlinear nature of a lithographic film system

An attempt was made to obtain a set of spatial transfer functions which would allow the prediction of output effective exposure distributions for a nonlinear lithographic film system. Slit exposures were used as one-dimensional system inputs. It was proposed that the use of slits would allow the calculation of a general system transfer function to be simplified. The mathematical model chosen to describe this nonlinear transfer was shown to be invalid due to the nonlinear relationship of small area system gain (small area output effective exposure divided by the input exposure) as a function on input exposure. The model,, based on a condensation of the multidimensional MacLaurin series, required this relationship to be linear. Data obtained from the small area effective exposure distributions allowed the calculation of a small area semi-specular density vs. relative log exposure curve. There existed a dramatic reduction in contrast for the small area curve as compared with the large area characteristics of the lithographic film system

Anti-HER2 IgY antibody-functionalized single-walled carbon nanotubes for detection and selective destruction of breast cancer cells

BACKGROUND: Nanocarrier-based antibody targeting is a promising modality in therapeutic and diagnostic oncology. Single-walled carbon nanotubes (SWNTs) exhibit two unique optical properties that can be exploited for these applications, strong Raman signal for cancer cell detection and near-infrared (NIR) absorbance for selective photothermal ablation of tumors. In the present study, we constructed a HER2 IgY-SWNT complex and demonstrated its dual functionality for both detection and selective destruction of cancer cells in an in vitro model consisting of HER2-expressing SK-BR-3 cells and HER2-negative MCF-7 cells. METHODS: The complex was constructed by covalently conjugating carboxylated SWNTs with anti-HER2 chicken IgY antibody, which is more specific and sensitive than mammalian IgGs. Raman signals were recorded on Raman spectrometers with a laser excitation at 785 nm. NIR irradiation was performed using a diode laser system, and cells with or without nanotube treatment were irradiated by 808 nm laser at 5 W/cm(2 )for 2 min. Cell viability was examined by the calcein AM/ethidium homodimer-1 (EthD-1) staining. RESULTS: Using a Raman optical microscope, we found the Raman signal collected at single-cell level from the complex-treated SK-BR-3 cells was significantly greater than that from various control cells. NIR irradiation selectively destroyed the complex-targeted breast cancer cells without harming receptor-free cells. The cell death was effectuated without the need of internalization of SWNTs by the cancer cells, a finding that has not been reported previously. CONCLUSION: We have demonstrated that the HER2 IgY-SWNT complex specifically targeted HER2-expressing SK-BR-3 cells but not receptor-negative MCF-7 cells. The complex can be potentially used for both detection and selective photothermal ablation of receptor-positive breast cancer cells without the need of internalization by the cells. Thus, the unique intrinsic properties of SWNTs combined with high specificity and sensitivity of IgY antibodies can lead to new strategies for cancer detection and therapy

Stress Distribution Due to a Tangential Concentrated Load in a Thin Cylinder

A solution is shown for stress distribution in an infinite strip with a transverse concentrated load acting at its center. Deformation relations are satisfied to permit this strip to be rolled transversely into an infinite cylinder. Equilibrium conditions are then satisfied by adding a pressure distribution normal to the surface of this cylinder. The stress due to this pressure distribution is solved by methods previously developed for thin cylinders are superposed on the strip stress. Results show that the stresses are nearly the same as those obtained by the elementary methods of strength of materials except near the point of application of the load, where there are localized bending stresses. This bending can be evaluated by the thin cylinder methods, but the process is very involved and a simpler approach is desired. This is found by considering the resultant of the pressure distribution to be a moment applied at the loading point. Two methods of analyzing stress in a thin cylinder loaded with a circumferential couple are shown and deformation curves plotted. The stress criterion is shown to be the normal stress developed near the load in the infinite (unrolled) strip