21,052 research outputs found
The Tcard Implementation Failure - The Need to Reconfigure Pre-existing Structures
The Tcard was first promised in time for the 2000 Sydney Olympics, but serious implementation plans only started in 2003 when the company ERG was contracted to deliver the Tcard. An amendment bill was passed to establish an organisation to overlook the technical rollout of the Tcard and massive financial investment followed. However, the Tcard was never implemented and the contract with ERG was cancelled in 2008. Meanwhile other global cities – Tokyo, Hong Kong, Seoul, London as well as other Australian cities have successfully implemented smartcard systems over the last two decades. This study uses two theoretical frameworks to find out what caused the failure of Tcard implementation. Both frameworks reveal that the key actors’ decisions to leave pre-existing legacy fares and bureaucratic structures led to the failure. The study also uncovers beyond the direct findings of the two frameworks, exposing that key actors failed to reform pre-existing structures due to their confinement in electoral interests, causing policy myopia and a major misunderstanding of public demands on transportation
The Tcard Implementation Failure - The Need to Reconfigure Pre-existing Structures
The Tcard was first promised in time for the 2000 Sydney Olympics, but serious implementation plans only started in 2003 when the company ERG was contracted to deliver the Tcard. An amendment bill was passed to establish an organisation to overlook the technical rollout of the Tcard and massive financial investment followed. However, the Tcard was never implemented and the contract with ERG was cancelled in 2008. Meanwhile other global cities – Tokyo, Hong Kong, Seoul, London as well as other Australian cities have successfully implemented smartcard systems over the last two decades. This study uses two theoretical frameworks to find out what caused the failure of Tcard implementation. Both frameworks reveal that the key actors’ decisions to leave pre-existing legacy fares and bureaucratic structures led to the failure. The study also uncovers beyond the direct findings of the two frameworks, exposing that key actors failed to reform pre-existing structures due to their confinement in electoral interests, causing policy myopia and a major misunderstanding of public demands on transportation
A 2D percolation-based model for characterizing the piezoresistivity of carbon nanotube-based films
Carbon nanotubes (CNTs) have attracted considerable attention due to their unique electrical, mechanical, and electromechanical properties. In particular, thin films formed by embedding CNTs in polymer matrices have been shown to exhibit strain-sensitive electromechanical properties, which can serve as an alternative to traditional strain sensors. Although numerous experimental studies have characterized their electrical properties and piezoresistivity, it remains unclear as to what nano-scale mechanisms dominate to govern nanocomposite electromechanical properties. Therefore, the objective of this study is to create a two-dimensional (2D) percolation-based numerical model to understand the electrical and coupled electromechanical behavior of CNT-based thin films. First, a percolation-based model with randomly dispersed straight nanotubes was generated. Second, the percolation and unstrained electrical properties of the model were evaluated as a function of CNT density and length. Next, uniaxial tensile–compressive strains were applied to the model for characterizing their electromechanical response and piezoresistivity. In addition, the effects of different intrinsic strain sensitivities of individual nanotubes were also considered. The results showed that bulk film strain sensitivity was strongly related to CNT density, length, and its intrinsic strain sensitivity. In particular, it was found that strain sensitivity decreased with increasing CNT density. While these strain sensitivity trends were consistent for different intrinsic CNT gage factors, the results were more complicated near the percolation threshold. These results were also compared to other experimental research so as to understand how different nano-scale parameters propagate and affect bulk film response
Intrinsic spin torque without spin-orbit coupling
We derive an intrinsic contribution to the nonadiabatic spin torque for nonuniform magnetic textures. It differs from previously considered contributions in several ways and can be the dominant contribution in some models. It does not depend on the change in occupation of the electron states due to the current flow but rather is due to the perturbation of the electronic states when an electric field is applied. Therefore it should be viewed as electric-field-induced rather than current-induced. Unlike previously reported nonadiabatic spin torques, it does not originate from extrinsic relaxation mechanisms or spin-orbit coupling. This intrinsic nonadiabatic spin torque is related by a chiral connection to the intrinsic spin-orbit torque that has been calculated from the Berry phase for Rashba systems.1197Ysciescopu
Perpendicular magnetic anisotropy of two-dimensional Rashba ferromagnets
We compute the magnetocrystalline anisotropy energy within two-dimensional Rashba models. For a ferromagnetic free-electron Rashba model, the magnetic anisotropy is exactly zero regardless of the strength of the Rashba coupling, unless only the lowest band is occupied. For this latter case, the model predicts in-plane anisotropy. For a more realistic Rashba model with finite band width, the magnetic anisotropy evolves from in-plane to perpendicular and back to in-plane as bands are progressively filled. This evolution agrees with first-principles calculations on the interfacial anisotropy, suggesting that the Rashba model captures energetics leading to anisotropy originating from the interface provided that the model takes account of the finite Brillouin zone. The results show that the electron density modulation by doping or an external voltage is more important for voltage-controlled magnetic anisotropy than the modulation of the Rashba parameter.115Ysciescopu
High efficiency In Vivo genome engineering with a simplified 15-RVD GoldyTALEN design
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Cross inoculation of rumen fluid to improve dry matter disappearance and its effect on bacterial composition using an in vitro batch culture model
Environmental pressures of ruminant production could be reduced by improving digestive efficiency. Previous in vivo attempts to manipulate the rumen microbial community have largely been unsuccessful probably due to the influencing effect of the host. Using an in vitro consecutive batch culture technique, the aim of this study was to determine whether manipulation was possible once the bacterial community was uncoupled from the host. Two cross inoculation experiments were performed. Rumen fluid was collected at time of slaughter from 11 Holstein-Friesian steers from the same herd for Experiment 1, and in Experiment 2 were collected from 11 Charolais cross steers sired by the same bull and raised on a forage only diet on the same farm from birth. The two fluids that differed most in their in vitro dry matter disappearance (IVDMD; “Good,” “Bad”) were selected for their respective experiment. The fluids were also mixed (1:1, “Mix”) and used to inoculate the model. In Experiment 1, the mixed rumen fluid resulted in an IVDMD midway between that of the two rumen fluids from which it was made for the first 24 h batch culture (34, 29, 20 g per 100 g DM for the Good, Mix, and Bad, respectively, P < 0.001) which was reflected in fermentation parameters recorded. No effect of cross inoculation was seen for Experiment 2, where the Mix performed most similarly to the Bad. In both experiments, IVDMD increased with consecutive culturing as the microbial population adapted to the in vitro conditions and differences between the fluids were lost. The improved performance with each consecutive batch culture was associated with reduced bacterial diversity. Increases in the genus Pseudobutyrivibrio were identified, which may be, at least in part, responsible for the improved digestive efficiency observed, whilst Prevotella declined by 50% over the study period. It is likely that along with host factors, there are individual factors within each community that prevent other microbes from establishing. Whilst we were unable to manipulate the bacterial community, uncoupling the microbiota from the host resulted in changes in the community, becoming less diverse with time, likely due to environmental heterogeneity, and more efficient at digesting DM
An Iterative CT Reconstruction Algorithm for Fast Fluid Flow Imaging
The study of fluid flow through solid matter by computed tomography (CT) imaging has many applications, ranging from petroleum and aquifer engineering to biomedical, manufacturing, and environmental research. To avoid motion artifacts, current experiments are often limited to slow fluid flow dynamics. This severely limits the applicability of the technique. In this paper, a new iterative CT reconstruction algorithm for improved a temporal/spatial resolution in the imaging of fluid flow through solid matter is introduced. The proposed algorithm exploits prior knowledge in two ways. First, the time-varying object is assumed to consist of stationary (the solid matter) and dynamic regions (the fluid flow). Second, the attenuation curve of a particular voxel in the dynamic region is modeled by a piecewise constant function over time, which is in accordance with the actual advancing fluid/air boundary. Quantitative and qualitative results on different simulation experiments and a real neutron tomography data set show that, in comparison with the state-of-the-art algorithms, the proposed algorithm allows reconstruction from substantially fewer projections per rotation without image quality loss. Therefore, the temporal resolution can be substantially increased, and thus fluid flow experiments with faster dynamics can be performed
Oral health and later coronary heart disease: Cohort study of one million people
AIMS:
Systematic reviews report an association between poorer oral health and an increased risk of coronary heart disease. This contentious relationship may not be causal but existing studies have been insufficiently well powered comprehensively to examine the role of confounding, particularly by cigarette smoking. Accordingly, we sought to examine the role of smoking in generating the relationship between oral health and coronary heart disease in life-long non-smokers.
METHODS AND RESULTS:
In the Korean Cancer Prevention Study, 975,685 individuals (349,579 women) aged 30–95 years had an oral examination when tooth loss, a widely used indicator of oral health, was ascertained. Linkage to national mortality and hospital registers over 21 years of follow-up gave rise to 64,784 coronary heart disease events (19,502 in women). In the whole cohort, after statistical adjustment for age, there was a moderate, positive association between tooth loss and coronary heart disease in both men (hazard ratio for seven or more missing teeth vs. none; 95% confidence interval 1.08; 1.02, 1.14; Ptrend across tooth loss groups <0.0001) and women (1.09; 1.01, 1.18; Ptrend 0.0016). Restricting analyses to a subgroup of 464,145 never smokers (25,765 coronary heart disease events), however, resulted in an elimination of this association in men (1.01; 0.85, 1.19); Ptrend 0.7506) but not women (1.08; 0.99, 1.18; Ptrend 0.0086).
CONCLUSION: In men in the present study, the relationship between poor oral health and coronary heart disease risk appeared to be explained by confounding by cigarette smoking so raising questions about a causal link
Systemic inflammation and suicide risk: cohort study of 419 527 Korean men and women
BACKGROUND: Data from only one study have been used to examine the relationship between systemic inflammation and later suicide risk, and a strong positive association was apparent. More research is needed, particularly looking at gender, not least because women are seemingly more vulnerable to inflammation-induced mood changes than men. METHODS: The Korean Cancer Prevention Study had a cohort of over 1 million individuals aged 30-95 years at baseline examination between 1992 and 1995, when white blood cell count, our marker of systemic inflammation, was assessed. RESULTS: A mean of 16.6 years of mortality surveillance gave rise to 1010 deaths from suicide in 106 643 men, and 1019 deaths from suicide in 312 884 women. There was little evidence of an association between our inflammation marker and suicide mortality in men after multiple adjustments. In women, however, those in the second inflammation quartile and higher experienced around 30% increase risk of death (HR 1.35; 95% CI: 1.11-1.64). CONCLUSIONS: Higher levels of systemic inflammation were moderately related to an elevated risk of suicide death in women but not in men
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