2,662 research outputs found
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Searching for Policy Priorities in the Formulation of a Freight Transport Strategy: An Analysis of Freight Industry Attitudes Towards Policy Initiatives
An efficient and effective freight transport strategy can be aided by early professional contributions from key stakeholders. One broad group who have historically been given limited opportunity to influence the drafting of a freight strategy, at least in Australia, are commercial road users and shippers who manufacture and distribute goods. Utilising a data set collected in Australia in 1996 from a sample of organisations involved directly and indirectly in road freight transportation, views were sought on road infrastructure changes, new road infrastructure, non-road infrastructure needs, and transport policies. An optimal scaling approach using non-linear canonical correlation is implemented to search for structural relationships between the underlying policy and infrastructure dimensions and the various industry categories. This framework provides a very powerful mechanism for identifying policy priorities supported or otherwise by stakeholder classes
Bus rapid transit systems: A comparative assessment
There is renewed interest in many developing and developed countries in finding ways of providing efficient and effective public transport that does not come with a high price tag. An increasing number of nations are asking the question – what type of public transport system can deliver value for money? Although light rail has often been promoted as a popular ‘solution’, there has been progressively emerging an attractive alternative in the form of bus rapid transit (BRT). BRT is a system operating on its own right-of-way either as a full BRT with high quality interchanges, integrated smart card fare payment and efficient throughput of passengers alighting and boarding at bus stations; or as a system with some amount of dedicated right-of-way (light BRT) and lesser integration of service and fares. The notion that buses essentially operate in a constrained service environment under a mixed traffic regime and that trains have privileged dedicated right-of-way, is no longer the only sustainable and valid proposition. This paper evaluates the status of 44 BRT systems in operation throughout the world as a way of identifying the capability of moving substantial numbers of passengers, using infrastructure whose costs overall and per kilometre are extremely attractive. When ongoing lifecycle costs (operations and maintenance) are taken into account, the costs of providing high capacity integrated BRT systems are an attractive option in many contexts
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Greenhouse Gas Emissions and Australian Commutersà Attitudes and Behaviour Concerning Abatement Policies and Personal Involvement
Public interest in the environment is building as we gain information about the deterioration in air quality and the potential threat of global warming. This research addresses the dichotomy between an individual’s behavior and his or her attitudinal support for policies which are promoted as benefiting the environment. We study how responses to attitudinal survey questions are interrelated, and how such responses are related to actual travel behavior using data from a survey undertaken in six capital cities in Australia in 1994. A measurement model is used to establish a set of latent attitudinal factors, and these factors are related in a structural equations model to a set of behavioral variables representing commuterÃs mode choice and choice of compressed work schedules, conditioned by a set of exogenous variables. We find that individuals with a strong environmental commitment are more likely to be female, from smaller households with fewer cars, be either under 30 years old or over 50 years old, have high household income and be highly educated. However, women are likely to view the car as a status symbol, and this attitude is conducive to choice of solo driving. We also find that mode choice influences attitudes; commuters who use public transport are more likely to support policies aimed at reducing greenhouse gas emissions. Our conclusion is that switching commuters away from solo driving can have effects that transcend the benefit obtained from reduced vehicle use for the journey to work alone
The Trip Chaining Activity of Sydney Residents: A Cross- Section Assessment by Age Group with a focus on Seniors
In this paper we use a pooled (2002-2004) cross-section of the Sydney travel survey, an annual continuous survey since 1997, to investigate the current profile of trip chaining travel activity of individual’s in 5-year groups, with a particular focus on those over 64 years old (i.e., seniors), given the aging of the population. Multiple Correspondence Analysis is used to establish causality of nonlinear and non-monotonic relationships between socioeconomic descriptors and measures of travel behaviour (assessed as trip chains). A benchmark setting for today not only establishes the way in which the elderly currently ‘cope’ with the existing supply network and the available modal alternatives, given their needs, but also is useful in providing hints as to what might be the key emerging transport policy and planning challenges in the future to serve this growing and increasingly influential population sub-strata. The main policy finding is that after age 64, travel demand shifts from car driving (partly linked to loss of driving license, but partly through choice), to car passenger and then to public transport in complex trip chains, especially for singles and for all women
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Driving Behaviour of Long Distance Truck Drivers: The Effects of Schedule Compliance on Drug Use and Speeding Citations
This paper reports the results of an econometric analysis of the influences on on-road behaviour of long distance truck drivers in Australia. The approach is couched in terms of a utility maximisation framework in which a driver trades-off economic reward with occupational risk. The physical risks to the driver due to driving while fatigued are proxied by the use of stimulants. Drawing on a 1990 survey of a sample of 402 truck drivers selected from owner drivers and employee drivers, we evaluate a number of alternative hypotheses on the relationship between drug taking, compliance with schedules and the propensity to speed. A system of structural equations is specified to test alternative hypotheses on causality between the endogenous variables and a set of exogenous effects. The models are estimated using distribution-free methods for mixed dichotomous and continuous variables. The main findings within the set of endogenous variables is that increasing speed is positively influenced by the propensity to take stay-awake pills which is itself positively influenced by the propensity to self-impose schedules. After controlling for a number of contextual influences on the endogenous variables, rates of financial reward have a significant impacts on all three endogenous variables. This study has highlighted the complex relationships which exist between speeding, social behaviour and economic reward
Exploring the use of pulsed erbium lasers to retrieve a zirconia crown from a zirconia implant abutment
Background
Removal of cement-retained implant fixed restorations when needed, can be challenging. Conventional methods of crown removal are time consuming and costly for patients and practitioners. This research explored the use of two different types of pulsed erbium lasers as a non-invasive tool to retrieve cemented zirconia crowns from zirconia implant abutments. Materials and methods
Twenty identical zirconia crowns were cemented onto 20 identical zirconia prefabricated abutments using self-adhesive resin cement. The specimens were divided into two groups for laser assisted crown removal; G1 for erbium-doped yttrium aluminum garnet laser (Er:YAG), and G2 for erbium, chromium-doped yttrium, scandium, gallium and garnet (Er,Cr:YSGG). For the G1, after the first crown removal, the specimens were re-cemented and removed again using the Er:YAG laser. Times needed to remove the crowns were recorded and analyzed using ANOVA (α = 0.05). The surfaces of the crown and the abutment were further examined using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses.
Results
The average times of zirconia crown removal from zirconia abutments were 5 min 20 sec and 5 min 15 sec for the Er:YAG laser of first and second experiments (G1), and 5 min 55 sec for the Er,Cr:YSGG laser experiment (G2). No statistical differences were observed among the groups. SEM and EDS examinations of the materials showed no visual surface damaging or material alteration from the two pulsed erbium lasers.
Conclusions
Both types of pulsed erbium lasers can be viable alternatives for retrieving a zirconia crown from a zirconia implant abutment. Despite operating at different wavelengths, the Er:YAG and Er,Cr:YSGG lasers, perform similarly in removing a zirconia crown from a zirconia implant abutment with similar parameters. There are no visual and elemental composition damages as a result of irradiation with pulsed erbium lasers
Light dark forces at flavor factories
SuperB experiment could represent an ideal environment to test a new U (1)
symmetry related to light dark forces candidates. A promising discovery channel
is represented by the resonant production of a boson U, followed by its decay
into lepton pairs. Beyond approximations adopted in the literature, an exact
tree level calculation of the radiative processes and corresponding QED
backgrounds is performed, including also the most important higher-order
corrections. The calculation is implemented in a release of the generator
BabaYaga@NLO useful for data analysis and interpretation. The distinct features
of U boson production are shown and the statistical significance is analysed
Mitochondria DNA mutations cause sex-dependent development of hypertension and alterations in cardiovascular function
Aging is associated with conduit artery stiffening that is a risk factor for and can precede hypertension and ventricular dysfunction. Increases in mitochondria DNA (mtDNA) frequency have been correlated with aging. Mice with a mutation in the encoding domain (D257A) of a proof-reading deficient version of mtDNA polymerase-γ (POLG) have musculoskeletal features of premature aging and a shortened lifespan. However, few studies using these mice have investigated the effects of mtDNA mutations on cardiovascular function. We hypothesized that the proof-reading deficient mtDNA POLG leads to arterial stiffening, hypertension, and ventricular hypertrophy. Ten to twelve month-old D257A mice (n=13) and age- and sex-matched wild-type controls (n=13) were catheterized for hemodynamic and ventricular function measurements. Left common carotid arteries (LCCA) were harvested for mechanical tests followed by histology. Male D257A mice had pulmonary and systemic hypertension, arterial stiffening, larger LCCA diameter (701±45 vs. 597±60 μm), shorter LCCA axial length (8.96±0.56 vs. 10.10±0.80 mm), and reduced hematocrit (29.1±6.1 vs. 41.3±8.1; all p<0.05). Male and female D257A mice had biventricular hypertrophy (p<0.05). Female D257A mice did not have significant increases in pressure or arterial stiffening, suggesting that the mechanisms of hypertension or arterial stiffening from mtDNA mutations differ based on sex. Our results lend insight into the mechanisms of age-related cardiovascular disease and may point to novel treatment strategies to address cardiovascular mortality in the elderly
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