3,903 research outputs found

    The use of heart rate indices and subjective questionnaires in the determination of fatigue in motor-manual tree felling and delimbing operations in New Zealand exotic plantation forests : a thesis presented in partial fulfilment of the requirements for the degree of Master of Business Studies in Ergonomics at Massey University

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    This study assessed the use of heart rate indices and subjective questionnaires in the determination of fatigue in motor-manual tree felling operations in New Zealand exotic plantation forests. The research design consisted of a causal study utilising an amalgamation of both observational and ex post facto data collection techniques employing a cross sectional case study approach within a field study research environment. Findings from the research indicate that motor-manual tree felling and delimbing are tasks not necessarily analogous with excessively high levels of fatigue, even though the physiological measures categorised motor-manual felling and delimbing as being moderate to heavy workload tasks. Chronic fatigue was avoided, and acute fatigue mitigated by the effective use of the fallers self-pacing mechanism, combined with both structured and spontaneous rest breaks analogous with the work method adopted by motor-manual fallers. Consequently, production was not negatively affected by the progression of the working day. Poor work postures commonly adopted by the fallers encourage the progressive development musculo-skeletal damage. Hazards encountered by the subjects followed national trends for felling and trimming. Significant decreases in thermal comfort and sensation ratings occurred, accompanied by an increase in the skin wettedness rating and higher thermal regulation ratings for the majority of the fallers. No discernible increase in mental fatigue could be identified during the study. The ambient thermal environment and work site terrain had minimal effect on the subjects performance levels or physiological and psycho-physiological loadings

    Escaping poverty traps?: Collective action and property rights in post-war rural Cambodia

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    "This paper introduces and applies an analytical framework to study how formal and informal institutions influence socio-economic change and poverty reduction in rural Cambodia, giving specific reference to property rights and collective action. It focuses on emerging endogenous mechanisms of cooperation as well as on the role of external actors and instruments in forming or enhancing collective action institutions, and enforcing use and ownership rights among the rural poor. Within this framework key contextual factor, such as asset endowments, legal structures, and power relations, have an impact on poverty and rural livelihoods, but are also mediated and changed by property right regimes and local cooperation. Findings indicate that access to and use of natural capital still contributes significantly to rural incomes. Access to natural resources is, however, defined by multiple and overlapping rights, both private and common ones, which are, in turn, governed by formal and informal patterns of cooperation. Collective action also contributes to improve livelihoods. Nevertheless, depending on asset endowments, differences exist in the degree of participation. Owing to Cambodia's recent history of genocide, forced collectivization and resettlement, property rights regimes have been severely affected, remain contested, and are re-established only slowly. In this context, the mutual trust necessary for successful cooperation in common property issues is severely undermined." authors' abstractCollective action, Property rights, Post-war, Rural development, Livelihoods,

    The effect of environmental variability on livestock and land-use management: the Borana Plateau, Southern Ethiopia

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    The Borana people are the predominant ethnic group on the Borana Plateau in southern Ethiopia, who have recently increased their reliance on crops. Rainfall in the region averages between 353 mm to 873 mm; variability is high, with coefficients of variation ranging from .21 to .68. Anectdotal evidence implies that the vulnerability of pastoralist households to drought is increasing; stock levels increase dramatically during good rainfall years but plummet when rainfall is poor, indicating that the drought cycle is becoming more pronounced. In recent years, there has also been a dramatic increase in land allocated to crops, and land allocated to pastures that are either privatized or accessible to only a small sub-group of people. It is hypothesized that one of the key determinants of the productivity and sustainability of the systems is the ability of community members to cooperate over the use and maintenance of these resources. In this paper, we develop indicators of cooperation and examine factors affecting these indicators. We then use these indicators to determine the impact of cooperation on stock densities and land allocation patterns. Results indicate that cooperation is positively related to factors that increase the profitability of livestock, but negatively related to the total number of households, the use of community pastures by non-community members, and heterogeneity of wealth within the community.Ethiopia., Pastoral systems Environmental aspects Africa., Land use Ethiopia., Livestock., Crops.,

    Quasar Tomography: Unification of Echo Mapping and Photoionisation Models

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    Reverberation mapping uses time-delayed variations in photoionised emission lines to map the geometry and kinematics of emission-line gas in active galactic nuclei. In previous work, the light travel time delay tau=R(1+cos(theta))/c and Doppler shift v give a 2-d map Psi(tau,v) for each emission line. Here we combine the velocity-delay information with photoionisation physics in a maximum entropy fit to the full reverberating spectrum F_lam(lam,t) to recover a 5-d map of the differential covering fraction f(R,theta,n,N,v), with n and N the density and column density of the gas clouds. We test the method for a variety of geometries (shells, rings, disks, clouds, jets) by recovering a 3-d map f(R,theta,n) from reverberations in 7 uv emission lines. The best test recovers a hollow shell geometry, defining R to 0.15 dex, n to 0.3 dex, and ionisation parameter U ~ 1/(n R^2) to 0.1 dex. The results are sensitive to the adopted distance and luminosity, suggesting that these parameters may be measurable as well.Comment: Accepted 4 Sep 2002 for publication in MNRA

    Land-tenure policy reforms: Decollectivization and the Doi Moi system in Vietnam

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    millions fed, food security, rice, Land tenure, Land reform, Doi Moi, Decollectivization,
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