2,484 research outputs found

    Intervening for exhaustion

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    "The search for psychosocial factors that contribute to the aetiology and course of coronary heart disease (CHD) has been an energetic, although not always fruitful, pursuit for more than half a century. Around 20 years ago, Appels [1] identified a prodromal constellation of symptoms, including physical exhaustion and feelings of hopelessness, that preceded major CHD events. It was hypothesized that this syndrome of “vital exhaustion” (VE) was a causal risk factor for CHD events, and several observational studies demonstrating prospective associations between VE and subsequent events have been adduced as supporting the hypothesis [2], [3], [4] and [5]. In a recent commentary, however, we discussed the difficulties inherent in drawing causal conclusions from observational evidence [6]. Applying general arguments that are by now very well rehearsed [7] and [8], we suggested that considerations such as confounding by common antecedents of both VE and CHD and reverse causation could not be readily dismissed and resolution was likely only following experimental studies. For example, an explanation of these prospective associations that regards CHD events as the result of inflammatory processes involved in the progress of atherosclerosis and VE as a consequence of such processes is just as parsimonious as one that regards VE as a causal risk. It is also equally, if not more, plausible biologically; there is now substantial evidence that inflammatory cytokines communicate with the central nervous system contributing to illness behaviour and experience and fostering feelings of depression and fatigue [9]. We also posed the question of what implications do the results of observational studies of VE hold for treatment [6]. Again, we would argue that in the absence of experimental evidence, the implications are extremely limited."\ud \u

    Forest rotation lengths under carbon sequestration payments

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    Carbon dioxide emissions resulting from direct human activities, primarily fossil fuel use and land clearing, have altered the global carbon cycle. Carbon is absorbed (sequestered) by plant matter during photosynthesis, so that approximately 50% of the dry weight of a forest’s biomass is carbon. This paper examines how payments to foresters for the carbon sequestered in their trees would affect harvesting decisions. It uses a theoretical multi-crop model adapted from the original Faustmann formula to consider different scenarios of the degree of carbon liability incurred at the time of harvest, and their impact on the length of the optimal crop rotation. These results are then contrasted with the equivalent output from a numerical model based on a simulated New South Wales Pinus radiata plantation. The finding of the paper provides an insight into which carbon sequestration payment policy would be the best at aligning public and private incentives.carbon sequestration

    The Role of Auctions in Allocating Public Resources

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    This paper provides an economic framework within which to consider the effectiveness and limitations of auction markets. The paper looks at the use of auctions as a policy instrument and the effects of auction design on consumer interests, the efficient allocation of resources, and industry competitiveness.Australia; Research; Ascending-bid auction; Auctions; Bidders; Conservation funds; Descending-bid auction; Dutch auction; English auction; Environmental Management; First-price sealed-bid auction; Infrastructure; Markets; Oral auction; Outcry auction; Pollutant emission permits; Power supply contracts; Public resources; Radio- spectrum; Second-price sealed-bid auction Spectrum licences; Vickrey auction; Water rights;

    Responsiveness of Demand for Irrigation Water: A Focus on the Southern Murray-Darling Basin

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    The Productivity Commission staff working paper, 'Responsiveness of Demand for Irrigation Water: A Focus on the Southern Murray-Darling Basin', was released August 2004. This paper explores the determinants of the elasticity of demand for irrigation water. It focuses on three main irrigated industries - rice, dairy and horticulture - to gain a greater understanding of the value that farmers place on water as an input. This paper provides detail relating to farm decision behaviour and biophysical production realities faced by irrigators in the southern Murray-Darling Basin. The views expressed in this paper are those of the staff involved and do not necessarily reflect those of the Productivity Commission.Resource /Energy Economics and Policy,

    Modelling Water Trade in the Southern Murray-Darling Basin

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    Released in November 2004, the paper uses TERM-Water, a bottoms-up regional CGE model of the Australian economy, to examine the regional effects of expanding trade of irrigation water in the southern Murray- Darling Basin. The study finds that water trading dampens the impact of water allocation cuts on gross regional product (GRP). The benefits of introducing trading within irrigation districts are greater than the further benefits of expanding trade to between these regions. Permitting trade of seasonal allocations allows irrigators to reallocate water in reaction to climatic conditions and water availability - and it is this flexibility that enables GRP reductions to be minimised.southern murray-darling basin, CGE model, irrigation water, water allocation, water trade,

    Greenhouse gas emissions and the productivity growth of electricity generators

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    This paper analyses electricity generation in four Australian states and the Northern Territory in the late 1990s It finds that productivity growth estimates for electricity generators can change significantly when allowance is made for greenhouse gas emissions. Using an innovative analytical technique for incorporating environmental impacts in productivity estimates, it shows that productivity growth is overestimated when emission intensity is rising and underestimated when emission intensity is falling. This is because emissions are undesirable and so if they fall (grow) per unit of output then this will tend to increase (decrease) estimated productivity.greenhouse gas emissions - productivity growth - electricity - abatement

    Thermodynamics of Accelerating Black Holes

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    We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermo- dynamics, with the usual identification of entropy proportional to the area of the event horizon — even though the event horizon contains a conical singularity. We show how to generalise this result, formulating thermodynamics for black holes with varying conical deficits. We derive a new potential for the varying tension defects: the thermodynamic length, both for accelerating and static black holes. We discuss possible physical processes in which the tension of a string ending on a black hole might vary, and also map out the thermodynamic phase space of accelerating black holes and explore their critical phenomena. We then revisit the critical limit in which asymptotically-AdS black holes develop maximal conical deficits, first for a stationary rotating black hole, and then for an accelerated black hole, by taking various upper bounds for the parameters in the spacetimes presented. We explore the thermodynamics of these geometries and evaluate the reverse isoperimetric inequal- ity, and argue that the ultra-spinning black hole only violates this condition when it is nonaccelerating. Finally, we return to some of our earlier findings and adjust them in light of new results; a new expression for the mass is obtained by computing the dual stress-energy tensor for the spacetime and finding that it corresponds to a relativistic fluid with a nontrivial viscous shear tensor. We compare the holographic computation with the method of conformal completion showing it yields the same result for the mass

    Wheat functional genomics and engineering crop improvement

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    Genetic mapping and determination of the organization of the wheat genome are changing the wheat-breeding process. New initiatives to analyze the expressed portion of the wheat genome and structural analysis of the genomes of Arabidopsis and rice are increasing our knowledge of the genes that are linked to key agronomically important traits

    Integrating wheat nucleolus structure and function: Variation in the wheat ribosomal RNA and protein genes

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    We review the coordinated production and integration of the RNA (ribosomal RNA, rRNA) and protein (ribosomal protein, RP) components of wheat cytoplasmic ribosomes in response to changes in genetic constitution, biotic and abiotic stresses. The components examined are highly conserved and identified with reference to model systems such as human, Arabidopsis, and rice, but have sufficient levels of differences in their DNA and amino acid sequences to form fingerprints or gene haplotypes that provide new markers to associate with phenotype variation. Specifically, it is argued that populations of ribosomes within a cell can comprise distinct complements of rRNA and RPs to form units with unique functionalities. The unique functionalities of ribosome populations within a cell can become central in situations of stress where they may preferentially translate mRNAs coding for proteins better suited to contributing to survival of the cell. In model systems where this concept has been developed, the engagement of initiation factors and elongation factors to account for variation in the translation machinery of the cell in response to stresses provided the precedents. The polyploid nature of wheat adds extra variation at each step of the synthesis and assembly of the rRNAs and RPs which can, as a result, potentially enhance its response to changing environments and disease threats

    Strategic management: An Eastern Cape construction SME case study

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    Small and Medium-size Enterprises (SMEs) fulfil an important role in the long-term growth and development of the economy of the country. The development and growth of construction SMEs are important for all countries, as a strong SME base has the capacity to produce a high-quality infrastructure for the country. However, research has revealed the high failure rate of small businesses within the first five years of their existence in South Africa. In addition, research also indicated that lack of long-term planning and lack of strategic thinking are major contributing factors to the failure of most SMEs. For instance, despite the considerable growth in the industry in the past decade due to government’s considerable infrastructural spending occasioned by the 2010 FIFA World Cup, the majority of construction SMEs failed to use the opportunities gained in this period to develop into established construction entities. This study investigates how strategic management can be applied to address the problems faced by construction SMEs, and to explore techniques and tools of strategic management that can make a significant contribution to their growth and development. The research findings, based on a literature review and a qualitative research approach, suggest that, although many construction SMEs perform poorly, some have the potential to grow and develop into more established entities by proactively managing their firms strategically. In addition, the findings indicate that SMEs that practise strategic management perform better, and that there are many advantages for SMEs that adopt strategic management principles at the organisational level
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