72 resultados para R41 - Transportation: Demand, Supply, and Congestion


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Mixed-species restoration tree plantings are being established increasingly, contributing to mitigate climate change and restore ecosystems. Including nitrogen (N)-fixing tree species may increase carbon (C) sequestration in mixed-species plantings, as these species may substantially increase soil C beneath them. We need to better understand the role of N-fixers in mixed-species plantings to potentially maximize soil C sequestration in these systems. Here, we present a field-based study that asked two specific questions related to the inclusion of N-fixing trees in a mixed-species planting: 1) Do non-N-fixing trees have access to N derived from fixation of atmospheric N2 by neighbouring N-fixing trees? 2) Do soil microbial communities differ under N-fixing trees and non-N-fixing trees in a mixed-species restoration planting? We sampled leaves from the crowns, and litter and soils beneath the crowns of two N-fixing and two non-N-fixing tree species that dominated the planting. Using the 15N natural abundance method, we found indications that fixed atmospheric N was utilized by the non-N-fixing trees, most likely through tight root connections or organic forms of N from the litter layer, rather than through the decomposition of N-fixers litter. While the two N-fixing tree species that were studied appeared to fix atmospheric N, they were substantially different in terms of C and N addition to the soil, as well as microbial community composition beneath them. This shows that the effect of N-fixing tree species on soil carbon sequestration is species-specific, cannot be generalized and requires planting trails to determine if there will be benefits to carbon sequestration. © 2014 Elsevier Ltd.

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We introduce two new variations on the Nash demand game. One, like all known Nash-like demand games so far, has the Nash solution outcome as its equilibrium outcome. In the other, the range of solutions depends on an exogenous breakdown probability; surprisingly, the Kalai-Smorodinsky outcome proves to be the most robust equilibrium outcome. While the Kalai- Smorodinsky solution always finishes on top, there is no possible general ranking among the remaining solution concepts considered; in fact, the rest of the solution concepts take their turns at the bottom at various bargaining problems, depending on the specifics of the bargaining setup.

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This paper details a system dynamics model developed to simulate proposed changes to water governance through the integration of supply, demand and asset management processes. To effectively accomplish this, interconnected feedback loops in tariff structures, demand levels and financing capacity are included in the model design, representing the first comprehensive life-cycle modelling of potable water systems. A number of scenarios were applied to Australia's populated South-east Queensland region, demonstrating that introducing temporary drought pricing (i.e. progressive water prices set inverse with availability), in conjunction with supply augmentation through rain-independent sources, is capable of efficiently providing water security in the future. Modelling demonstrated that this alternative tariff structure reduced demand in scarcity periods thereby preserving supply, whilst revenues are maintained to build new water supply infrastructure. In addition to exploring alternative tariffs, the potential benefits of using adaptive pressure-retarded osmosis desalination plants for both potable water and power generation was explored. This operation of these plants for power production, when they would otherwise be idle, shows promise in reducing their net energy and carbon footprints. Stakeholders in industry, government and academia were engaged in model development and validation. The constructed model displays how water resource systems can be reorganised to cope with systemic change and uncertainty.

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Recruitment is known to influence distributions and abundances of benthic marine organisms. It is therefore important to document patterns of variability in recruitment and how these relate to patterns in established assemblages. This study provides an integrated assessment of the temporal and spatial variation in supply and recruitment of propagules and established populations of several macroalgae. Propagules in water samples from two stages of the incoming tide, recruitment to artificial substrata and percentage cover of species established on the shore were recorded every 2 months from December 1994 to October 1995, in two zones of an intertidal, wave-exposed rocky shore. Variability in recruitment was measured at three spatial scales: 10s cm, 100s cm and 100s m. Availability and recruitment of most taxa were greatest between April and August, although many species had available propagules and recruited throughout the year. Temporal variation in the established assemblages was, however, more species-specific. Differences in established assemblages between zones were reflected in differences in availability and recruitment of propagules between zones. Recruitment could not be predicted directly from supply of propagules, but the two processes were linked. For most species, the greatest variation in recruitment occurred at the smallest spatial scale of 10s cm, although there was also considerable large-scale (between site) variation in recruitment of several species. Results indicate that while pre-and post-settlement mortality are likely to influence macroalgal distribution and abundance, the temporal and spatial variability in supply and recruitment of propagules can explain much of the patchiness in macroalgal assemblages.

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This paper discusses the economic transition and the property market emergence in transition economies. It compares the Chinese property market with the Polish market. It preliminarily examines market emergence and maturity in the context of economic transition, comparing the transitions with the emphasis placed on commercial property markets especially their formation and behaviour. Supply and demand for commercial space in China and Poland are also contrasted. As commercial property market behaviour is somewhat driven by market structure formation process and the business cycle, the transition has provided a “common ground” that enables similarities between the property markets in China and Poland. The challenge for state intervention is mainly due to the agency problem which is also a problem in mature markets; it appears that transitional economies do share common features in their emerging property markets. This paper suggests state intervention in market formation and emergence is necessary and essential. However the actual formation and behaviour of property markets have some distinctive characteristics. Value or implication of the study include: knowing the stage of market emergence is essential for making investment decisions, especially when identifying markets with varying backgrounds. This paper is also relevant to policy-makers in the process of facilitating transitions in emerging markets.

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Purpose – This paper aims to provide an invaluable insight into long-term forecasting of demand for aged care facilities. This will ensure the provision of adequate supply by government bodies, stakeholders and developers in order to meet the anticipated level of demand, without creating an over-supply or an under-supply scenario.

Design/methodology/approach – Using an innovative approach, different data sources were collectively used to forecast separate individual supply and demand levels, which were then examined together in order to measure the difference between the two variables between 2009-2020. A case study approach was used for Victoria, Australia.

Findings – The paper finds that, although there is excess supply between 2009-2010 and 2019-2020, the period between 2010 and 2019 will experience an under-supply period which cannot be easily rectified over the short term.

Research limitations/implications –
The case study was limited to residential care facilities in Victoria, Australia, although some countries have substantially different age profiles and accommodation supply for older residents. Forecasts are based on information sources from various data suppliers and collectively analysed.

Practical implications – The results are also of direct interest to place managers and planning authorities who are charged with providing medium- and long-term visions and plans for specific locations. This type of research is essential when planning for the eventual aging of the population, where the methodology can be replicated in different areas. Most importantly, this research approach provides a solid basis for decisions regarding the supply of residential aged care facilities as opposed to a simple estimate.

Originality/value – The study adopted a unique approach to analysing the individual supply and demand components for aged care facilities over the long term. This approach is able to accurately determine when there will be an under-supply or over-supply situation and thus provide the opportunity to address the difference before it occurs. This will allow informed decisions about planning aged care facilities in the future to be made as required.

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Issue addressed: The determinants of individual and community mental health and wellbeing are diverse and many lie outside the sphere of action of the health sector. Developing the confidence and skills of these other sectors to contribute to improved mental health has been identified as a priority at State and national levels that requires the development of specific workforce capacity-building strategies. Methods: VicHealth developed and implemented a two day short course to raise the capacity of organisations from a range of sectors to contribute to the mental health and wellbeing of communities. The model of this short course was constructed to reflect the diverse sectors targeted, which included health, local government, community arts, sport and recreation, justice, and education. Results: Evaluation of the two year pilot program, with more than 1,000 participants, has identified a high degree of satisfaction with the content and delivery model of the course, with clear changes in knowledge, skills and practice having been achieved. Cross-sector understanding and collaborations between participants increased as a result of the course. Conclusions: Continuing demand for the course demonstrates clearly that mental health and well-being is relevant to the core business of a broad range of community and professional organisations. The course has increased the confidence and capacity of these sector representatives to take action on mental health as well as increased cross-sector dialogue and partnerships. The recruitment of trainers from diverse sectors was successful in promoting a key component of the program, which was the message that mental health promotion should be the business of all sectors.

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In this paper, we re-estimate the import and the export demand functions for Mauritius and South Africa using time series data. We use the bounds tests for cointegration and find evidence of a long-run relationship between import demand, income and prices for both countries. Our long run elasticities reveal that domestic income and relative prices have significant effects on the import demand for both countries, with income being the most important determinant. Furthermore, we find that while South Africa’s export demand is not responsive to relative prices or income; for Mauritius income is statistically significant.

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Any attempt to model an economy requires foundational assumptions about the relations between prices, values and the distribution of wealth. These assumptions exert a profound influence over the results of any model. Unfortunately, there are few areas in economics as vexed as the theory of value. I argue in this paper that the fundamental problem with past theories of value is that it is simply not possible to model the determination of value, the formation of prices and the distribution of income in a real economy with analytic mathematical models. All such attempts leave out crucial processes or make unrealistic assumptions which significantly affect the results. There have been two primary approaches to the theory of value. The first, associated with classical economists such as Ricardo and Marx were substance theories of value, which view value as a substance inherent in an object and which is conserved in exchange. For Marxists, the value of a commodity derives solely from the value of the labour power used to produce it - and therefore any profit is due to the exploitation of the workers. The labour theory of value has been discredited because of its assumption that labour was the only ‘factor’ that contributed to the creation of value, and because of its fundamentally circular argument. Neoclassical theorists argued that price was identical with value and was determined purely by the interaction of supply and demand. Value then, was completely subjective. Returns to labour (wages) and capital (profits) were determined solely by their marginal contribution to production, so that each factor received its just reward by definition. Problems with the neoclassical approach include assumptions concerning representative agents, perfect competition, perfect and costless information and contract enforcement, complete markets for credit and risk, aggregate production functions and infinite, smooth substitution between factors, distribution according to marginal products, firms always on the production possibility frontier and firms’ pricing decisions, ignoring money and credit, and perfectly rational agents with infinite computational capacity. Two critical areas include firstly, the underappreciated Sonnenschein-Mantel- Debreu results which showed that the foundational assumptions of the Walrasian general-equilibrium model imply arbitrary excess demand functions and therefore arbitrary equilibrium price sets. Secondly, in real economies, there is no equilibrium, only continuous change. Equilibrium is never reached because of constant changes in preferences and tastes; technological and organisational innovations; discoveries of new resources and new markets; inaccurate and evolving expectations of businesses, consumers, governments and speculators; changing demand for credit; the entry and exit of firms; the birth, learning, and death of citizens; changes in laws and government policies; imperfect information; generalized increasing returns to scale; random acts of impulse; weather and climate events; changes in disease patterns, and so on. The problem is not the use of mathematical modelling, but the kind of mathematical modelling used. Agent-based models (ABMs), objectoriented programming and greatly increased computer power however, are opening up a new frontier. Here a dynamic bargaining ABM is outlined as a basis for an alternative theory of value. A large but finite number of heterogeneous commodities and agents with differing degrees of market power are set in a spatial network. Returns to buyers and sellers are decided at each step in the value chain, and in each factor market, through the process of bargaining. Market power and its potential abuse against the poor and vulnerable are fundamental to how the bargaining dynamics play out. Ethics therefore lie at the very heart of economic analysis, the determination of prices and the distribution of wealth. The neoclassicals are right then that price is the enumeration of value at a particular time and place, but wrong to downplay the critical roles of bargaining, power and ethics in determining those same prices.

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Commuting to work is one of the most important and regular routines of transportation in towns and cities. From a geographic perspective, the length of people’s commute is influenced, to some degree, by the spatial separation of their home and workplace and the transport infrastructure. The rise of car ownership in Australia from the 1950s to the present was accompanied by a considerable decrease of public transport use. Currently there is an average of 1.4 persons per car in Australia, and private cars are involved in approximately 90% of the trips, and public transportation in only 10%. Increased personal mobility has fuelled the trend of decentralised housing development, mostly without a clear planning for local employment, or alternative means of transportation. Transport sector accounts for 14% of Australia’s net greenhouse gas emissions. Without further policy action, Australia’s emissions are projected to continue to increase. The Australian Federal Government and the new Department of Climate Change have recently published a set of maps showing that rising seas would submerge large parts of Victoria coastal region. Such event would lead to major disruption in planned urban growth areas in the next 50 years with broad scale inundation of dwellings, facilities and road networks. The Greater Geelong Region has well established infrastructure as a major urban centre and tourist destination and hence attracted the attention of federal and state governments in their quest for further development and population growth. As a result of its natural beauty and ecological sensitivity, scenarios for growth in the region are currently under scrutiny from local government as well as development agencies, scientists, and planners. This paper is part of a broad research in the relationship between transportation system, urban form, trip demand, and emissions, as a paramount in addressing the challenges presented by urban growth. Progressing from previous work focused on private cars, this present paper investigates the use of public transport as a mode for commuting in the Greater Geelong Region. Using a GIS based interaction model, it characterises the current use of the existing public transportation system, and also builds a scenario of increased use of the existing public transportation system, estimating potencial reductions in CO2 emissions. This study provides an improved understanding of the extent to which choices of transport mode and travel activity patterns, affect emissions in the context of regional networks. The results indicate that emissions from commuting by public transportation are significantly lower than those from commuting by private car, and emphasise that there are opportunities for large abatment in the greenhouse emissions from the transportation sector related to efforts in increasing the use of existing public transportation system.

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We examined the neuroendocrine and cellular stress responses of diploid and triploid rainbow trout Oncorhynchus mykiss to transportation. Juvenile diploid and triploid rainbow trout (28 and 26 g/fish average weight, respectively) were stocked at 100 g/L in replicate 70-L tanks and subjected to transportation for an 8-h period. Subsequent levels of plasma cortisol and glucose and of cellular hepatic glutathione (GSH) and heat shock protein 70 (Hsp70) were similar between ploidy groups, indicating that triploid fish respond to transportation in much the same way as diploid fish. A stationary treatment was also included that involved confinement of experimental fish in similar tanks without transport to determine to what extent high-density containment contributed to the stress response in the absence of the noise and vibration of transport. Unexpectedly, fish in the stationary treatment had significantly higher plasma cortisol and glucose levels than the transported fish; however, this might be attributable to a confounding effect of hyperoxia, as oxygen levels fluctuated between 150% and 460% saturation in the stationary tank, while those in the transported tank remained within 100–200% saturation. We suggest that when long stops are necessary while transporting fish, water agitators be used to preclude the additional stress of excessive gas saturation. This may be particularly important for triploid fish, which had lower hepatic GSH levels than diploid fish as well as a low level of mortality in the stationary treatment, unlike the diploid fish.

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Introduction
Throughout the world, alcohol consumption is common among adolescents. Adolescent alcohol use and misuse have prognostic significance for several adverse long-term outcomes, including alcohol problems, alcohol dependence, school disengagement and illicit drug use. The aim of this study was to evaluate whether randomisation to a community mobilisation and social marketing intervention reduces the proportion of adolescents who initiate alcohol use before the Australian legal age of 18, and the frequency and amount of underage adolescent alcohol consumption.
Method and analysis
The study comprises 14 communities matched with 14 non-contiguous communities on socioeconomic status (SES), location and size. One of each pair was randomly allocated to the intervention. Baseline levels of adolescent alcohol use were estimated through school surveys initiated in 2006 (N=8500). Community mobilisation and social marketing interventions were initiated in 2011 to reduce underage alcohol supply and demand. The setting is communities in three Australian states (Victoria, Queensland and Western Australia). Students (N=2576) will complete school surveys in year 8 in 2013 (average age 12). Primary outcomes: (1) lifetime initiation and (2) monthly frequency of alcohol use. Reports of social marketing and family and community alcohol supply sources will also be assessed. Point estimates with 95% CIs will be compared for student alcohol use in intervention and control communities. Changes from 2006 to 2013 will be examined; multilevel modelling will assess whether random assignment of communities to the intervention reduced 2013 alcohol use, after accounting for community level differences. Analyses will also assess whether exposure to social marketing activities increased the intervention target of reducing alcohol supply by parents and community members.

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Water supply and demand planning is often conducted independently of social and economic strategies. There are presently no comprehensive life-cycle approaches to modelling urban water balances that incorporate economic feedbacks, such as tariff adjustment, which can in turn create a financing capacity for investment responses to low reservoir levels. This paper addresses this gap, and presents a system dynamics model that augments the usual water utility representation of the physical linkages of water grids, by adding inter-connected feedback loops in tariff structures, demand levels and financing capacity. The model, applied in the south-east Queensland region in Australia, enables simulation of alternatives and analysis of stocks and flows around a grid or portfolio of bulk supplies including an increasing proportion of rain-independent desalination plants. Such rain-independent water production plants complement the rain-dependent sources in the region and can potentially offer indefinite water security at a price. The study also shows how an alternative temporary drought pricing regime not only defers costly bulk supply infrastructure but actually generates greater price stability than traditional pricing approaches. The model has implications for water supply planners seeking to pro-actively plan, justify and finance portfolios of rain-dependent and rain-independent bulk water supply infrastructure. Interestingly, the modelling showed that a temporary drought pricing regime not only lowers the frequency and severity of water insecurity events but also reduces the long-run marginal cost of water supply for the region when compared to traditional reactive planning approaches that focus on restrictions to affect demand in scarcity periods.

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To assess the degree to which reimbursement prices in Australia and England differ for a range of generic drugs, and to analyse the supply- and demand-side factors that may contribute to these differences.

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Coal comprises 70 per cent of China’s primary energy source and 80 per cent of China's electricity generation. This study investigates the long-run relationship between coal consumption-economic growth nexus considering both supply and demand side models in a multivariate framework over the period of 1978 and 2010. Our innovation in this paper is to include a coal-to-electricity efficiency indicator into the economic growth model ; and trade exposure in coal demand. Using Autoregressive Distributed Lag bounds testing approach, we find improvement in coal-to-efficiency indicator causes almost 35 per cent increase in real GDP in the long-run. The Toda-Yamamoto approach of causality test indicates unidirectional causality from coal consumption to economic growth; feedback effect both for coal-to-electricity efficiency indicator to economic growth and openness to coal consumption. For robustness check, using the generalised forecast error variance decomposition method we forecast the validity of causal relationships beyond the sample horizon. The paper suggests the role of advanced coal technologies will play a significant role along with other environmental and energy policies in maintaining sustainable economic growth in China .