5,789 research outputs found

    Prioritising project management competences across the software project life cycle

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    Purpose The purpose of this paper is to investigate the relative importance of project management (PM) competences across the different stages of a software project life cycle to identify competence development gaps and opportunities. Design/methodology/approach A deductive and quantitative approach was adopted to address the research questions with a web-based survey for data collection. Findings After reviewing the context of competences and PM competences, the importance of the PM competences overall and for specific stages in the project life cycle was analysed. The result highlights that functional and meta-competences are perceived to be the most important competence dimensions for software project practitioners. Originality/value This study makes three contributions. First, it consolidates PM competences into a set of 20 within four competence dimensions. Second, it prioritises these competences across the software project life cycle. Third, it identifies the significance of the inter-relationship between PM competences and project life cycle to reveal PM competence development gaps and opportunities

    Superfluid-insulator transition of the Josephson junction array model with commensurate frustration

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    We have studied the rationally frustrated Josephson-junction array model in the square lattice through Monte Carlo simulations of (2+1)(2+1)D XY-model. For frustration f=1/4f=1/4, the model at zero temperature shows a continuous superfluid-insulator transition. From the measurement of the correlation function and the superfluid stiffness, we obtain the dynamical critical exponent z=1.0z=1.0 and the correlation length critical exponent Ī½=0.4Ā±0.05\nu=0.4 \pm 0.05. While the dynamical critical exponent is the same as that for cases f=0f=0, 1/2, and 1/3, the correlation length critical exponent is surprisingly quite different. When f=1/5f=1/5, we have the nature of a first-order transition.Comment: RevTex 4, to appear in PR

    N_pN_n dependence of empirical formula for the lowest excitation energy of the 2^+ states in even-even nuclei

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    We examine the effects of the additional term of the type āˆ¼eāˆ’Ī»ā€²NpNn\sim e^{- \lambda' N_pN_n} on the recently proposed empirical formula for the lowest excitation energy of the 2+2^+ states in even-even nuclei. This study is motivated by the fact that this term carries the favorable dependence of the valence nucleon numbers dictated by the NpNnN_pN_n scheme. We show explicitly that there is not any improvement in reproducing Ex(21+)E_x(2_1^+) by including the extra NpNnN_pN_n term. However, our study also reveals that the excitation energies Ex(21+)E_x(2_1^+), when calculated by the NpNnN_pN_n term alone (with the mass number AA dependent term), are quite comparable to those calculated by the original empirical formula.Comment: 14 pages, 5 figure

    Mapping local optical densities of states in silicon photonic structures with nanoscale electron spectroscopy

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    Relativistic electrons in a structured medium generate radiative losses such as Cherenkov and transition radiation that act as a virtual light source, coupling to the photonic densities of states. The effect is most pronounced when the imaginary part of the dielectric function is zero, a regime where in a non-retarded treatment no loss or coupling can occur. Maps of the resultant energy losses as a sub-5nm electron probe scans across finite waveguide structures reveal spatial distributions of optical modes in a spectral domain ranging from near-infrared to far ultraviolet.Comment: 18 pages, 4 figure

    Phase Transitions in the Two-Dimensional XY Model with Random Phases: a Monte Carlo Study

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    We study the two-dimensional XY model with quenched random phases by Monte Carlo simulation and finite-size scaling analysis. We determine the phase diagram of the model and study its critical behavior as a function of disorder and temperature. If the strength of the randomness is less than a critical value, Ļƒc\sigma_{c}, the system has a Kosterlitz-Thouless (KT) phase transition from the paramagnetic phase to a state with quasi-long-range order. Our data suggest that the latter exists down to T=0 in contradiction with theories that predict the appearance of a low-temperature reentrant phase. At the critical disorder TKTā†’0T_{KT}\rightarrow 0 and for Ļƒ>Ļƒc\sigma > \sigma_{c} there is no quasi-ordered phase. At zero temperature there is a phase transition between two different glassy states at Ļƒc\sigma_{c}. The functional dependence of the correlation length on Ļƒ\sigma suggests that this transition corresponds to the disorder-driven unbinding of vortex pairs.Comment: LaTex file and 18 figure

    Moving Wigner Glasses and Smectics: Dynamics of Disordered Wigner Crystals

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    We examine the dynamics of driven classical Wigner solids interacting with quenched disorder from charged impurities. For strong disorder, the initial motion is plastic -- in the form of crossing winding channels. For increasing drive, the disordered Wigner glass can reorder to a moving Wigner smectic -- with the electrons moving in non-crossing 1D channels. These different dynamic phases can be related to the conduction noise and I(V) curves. For strong disorder, we show criticality in the voltage onset just above depinning. We also obtain the dynamic phase diagram for driven Wigner solids and prove that there is a finite threshold for transverse sliding, recently found experimentally.Comment: 4 pages, 4 postscript figure

    Real-time, label-free, intraoperative visualization of peripheral nerves and microvasculatures using multimodal optical imaging techniques

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    Accurate, real-time identification and display of critical anatomic structures, such as the nerve and vasculature structures, are critical for reducing complications and improving surgical outcomes. Human vision is frequently limited in clearly distinguishing and contrasting these structures. We present a novel imaging system, which enables noninvasive visualization of critical anatomic structures during surgical dissection. Peripheral nerves are visualized by a snapshot polarimetry that calculates the anisotropic optical properties. Vascular structures, both venous and arterial, are identified and monitored in real-time using a near-infrared laser-speckle-contrast imaging. We evaluate the system by performing in vivo animal studies with qualitative comparison by contrast-agent-aided fluorescence imaging

    Microbial nar-GFP cell sensors reveal oxygen limitations in highly agitated and aerated laboratory-scale fermentors

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    Background: Small-scale microbial fermentations are often assumed to be homogeneous, and oxygen limitation due to inadequate micromixing is often overlooked as a potential problem. To assess the relative degree of micromixing, and hence propensity for oxygen limitation, a new cellular oxygen sensor has been developed. The oxygen responsive E. coli nitrate reductase (nar) promoter was used to construct an oxygen reporter plasmid (pNar-GFPuv) which allows cell-based reporting of oxygen limitation. Because there are greater than 109 cells in a fermentor, one can outfit a vessel with more than 109 sensors. Our concept was tested in high density, lab-scale ( 5 L), fed-batch, E. coli fermentations operated with varied mixing efficiency - one verses four impellers. Results: In both cases, bioreactors were maintained identically at greater than 80% dissolved oxygen ( DO) during batch phase and at approximately 20% DO during fed-batch phase. Trends for glucose consumption, biomass and DO showed nearly identical behavior. However, fermentations with only one impeller showed significantly higher GFPuv expression than those with four, indicating a higher degree of fluid segregation sufficient for cellular oxygen deprivation. As the characteristic time for GFPuv expression (approx 90 min.) is much larger than that for mixing (approx 10 s), increased specific fluorescence represents an averaged effect of oxygen limitation over time and by natural extension, over space. Conclusion: Thus, the pNar-GFPuv plasmid enabled bioreactor-wide oxygen sensing in that bacterial cells served as individual recirculating sensors integrating their responses over space and time. We envision cell-based oxygen sensors may find utility in a wide variety of bioprocessing applications.open1123sciescopu

    Constellations of identity: place-ma(r)king beyond heritage

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    This paper will critically consider the different ways in which history and belonging have been treated in artworks situated in the Citadel development in Ayr on the West coast of Scotland. It will focus upon one artwork, Constellation by Stephen Hurrel, as an alternative to the more conventional landscapes of heritage which are adjacent, to examine the relationship between personal history and place history and argue the primacy of participatory process in the creation of place and any artwork therein. Through his artwork, Hurrel has attempted to adopt a material process through which place can be created performatively but, in part due to its non-representational form, proves problematic, aesthetically and longitudinally, in wholly engaging the community. The paper will suggest that through variants of ā€˜new genre public artā€™ such as this, personal and place histories can be actively re-created through the redevelopment of contemporary urban landscapes but also highlight the complexities and indeterminacies involved in the relationship between artwork, people and place
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