13,088 research outputs found

    Effects of strand and directional asymmetry on base-base coupling and charge transfer in double-helical DNA

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    Mechanistic models of charge transfer (CT) in macromolecules often focus on CT energetics and distance as the chief parameters governing CT rates and efficiencies. However, in DNA, features unique to the DNA molecule, in particular, the structure and dynamics of the DNA base stack, also have a dramatic impact on CT. Here we probe the influence of subtle structural variations on base-base CT within a DNA duplex by examining photoinduced quenching of 2-aminopurine (Ap) as a result of hole transfer (HT) to guanine (G). Photoexcited Ap is used as a dual reporter of variations in base stacking and CT efficiency. Significantly, the unique features of DNA, including the strandedness and directional asymmetry of the double helix, play a defining role in CT efficiency. For an (AT)(n) bridge, the orientation of the base pairs is critical; the yield of intrastrand HT is markedly higher through (A)n compared with (T)(n) bridges, whereas HT via intrastrand pathways is more efficient than through interstrand pathways. Remarkably, for reactions through the same DNA bridge, over the same distance, and with the same driving force, HT from photoexcited Ap to G in the 5' to 3' direction is more efficient and less dependent on distance than HT from 3' to 5'. We attribute these differences in HT efficiency to variations in base-base coupling within the DNA assemblies. Thus base-base coupling is a critical parameter in DNA CT and strongly depends on subtle structural nuances of duplex DNA

    Mapping, sensing and visualising the digital co-presence in the public arena

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    This paper reports on work carried out within the Cityware project using mobile technologies to map, visualise and project the digital co-presence in the city. This paper focuses on two pilot studies exploring the Bluetooth landscape in the city of Bath. Here we apply adapted and ‘digitally augmented’ methods for spatial observation and analysis based on established methods used extensively in the space syntax approach to urban design. We map the physical and digital flows at a macro level and observe static space use at the micro level. In addition we look at social and mobile behaviour from an individual’s point of view. We apply a method based on intervention through ‘Sensing and projecting’ Bluetooth names and digital identity in the public arena. We present early findings in terms of patterns of Bluetooth flow and presence, and outline initial observations about how people’s reaction towards the projection of their Bluetooth names practices in public. In particular we note the importance of constructing socially meaningful relations between people mediated by these technologies. We discuss initial results and outline issues raised in detail before finally describing ongoing work

    Farm Technical Efficiency and Extension

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    This paper presents a methodology for estimating technical efficiency levels for individual farms using both a fixed effects panel model and a stochastic production frontier approach. It tests whether the estimated technical efficiency levels are associated with measures of contact with the advisory service. The approach is applied to a panel of 307 farms drawn from the Irish National Farm Survey over the period 1984 to 1994. The results show evidence that extension contact has had a positive impact on agricultural output.

    Statistical Mechanics of 2+1 Gravity From Riemann Zeta Function and Alexander Polynomial:Exact Results

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    In the recent publication (Journal of Geometry and Physics,33(2000)23-102) we demonstrated that dynamics of 2+1 gravity can be described in terms of train tracks. Train tracks were introduced by Thurston in connection with description of dynamics of surface automorphisms. In this work we provide an example of utilization of general formalism developed earlier. The complete exact solution of the model problem describing equilibrium dynamics of train tracks on the punctured torus is obtained. Being guided by similarities between the dynamics of 2d liquid crystals and 2+1 gravity the partition function for gravity is mapped into that for the Farey spin chain. The Farey spin chain partition function, fortunately, is known exactly and has been thoroughly investigated recently. Accordingly, the transition between the pseudo-Anosov and the periodic dynamic regime (in Thurston's terminology) in the case of gravity is being reinterpreted in terms of phase transitions in the Farey spin chain whose partition function is just a ratio of two Riemann zeta functions. The mapping into the spin chain is facilitated by recognition of a special role of the Alexander polynomial for knots/links in study of dynamics of self homeomorphisms of surfaces. At the end of paper, using some facts from the theory of arithmetic hyperbolic 3-manifolds (initiated by Bianchi in 1892), we develop systematic extension of the obtained results to noncompact Riemannian surfaces of higher genus. Some of the obtained results are also useful for 3+1 gravity. In particular, using the theorem of Margulis, we provide new reasons for the black hole existence in the Universe: black holes make our Universe arithmetic. That is the discrete Lie groups of motion are arithmetic.Comment: 69 pages,11 figures. Journal of Geometry and Physics (in press

    Theology at the coal-face of hospitalisation - the development and evaluation of a postgraduate certificate in Healthcare Chaplaincy

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    Healthcare chaplaincy is working towards recognition as a registered health profession. An accredited programme of professional education is part of that process. The University of Glasgow supported by NHS Education for Scotland have developed a programme of professional education for healthcare chaplains that is integrated into an MSc. (MedSci) in healthcare. This article outlines the commissioning, development and evaluation of a postgraduate certificate in healthcare chaplaincy by students, clinical mentors and experienced healthcare chaplains. It also highlights an innovative approach to practice development in spiritual and religious care in healthcare

    Superorbital Period in the High Mass X-ray Binary 2S 0114+650

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    We report the detection of a superorbital period in the high-mass X-ray binary 2S 0114+650. Analyses of data from the Rossi X-ray Timing Explorer (RXTE) All-Sky Monitor (ASM) from 1996 January 5 to 2004 August 25 reveal a superorbital period of 30.7 +/- 0.1 d, in addition to confirming the previously reported neutron star spin period of 2.7 h and the binary orbital period of 11.6 d. It is unclear if the superorbital period can be ascribed to the precession of a warped accretion disc in the system.Comment: 5 pages, 5 figures, submitted to MNRAS 27th January 2005. Manuscript expanded to include discussion of evolution of periods, and hardness ratio variability. Number of figures increased from 5 to 9. Accepted for publication 19th December 200

    Human Resource Management in New Jersey State Government

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    In 2005, the State of New Jersey Department of Personnel commissioned the Heldrich Center to study the critical human resource management issues confronting New Jersey state government. This report highlights the study's findings including: the human resource management function must be elevated to a position of primacy in state government, the state must reengineer the Department of Personnel into an effective human resource management agency with a broader mission than overseeing transactions and compliance with statutes and regulations, and the state must support its human resource function with adequate staff resources
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