RESUMEN
Several partly overlapping diseases have Parkinsonism as a symptom and tools that may differentiate between these disorders would be helpful. The authors evaluated the discriminating properties of the objective automated posturo-locomotor-manual (PLM) L-DOPA test in regard to health, and the movement disorders Parkinson's disease (PD), multiple system atrophy (MSA), and progressive supranuclear palsy (PSP). A PLM test-retest procedure was performed in healthy controls (n = 37) and results were compared with PLM L-DOPA tests performed by 132 patients with Parkinsonism in intermediate to advanced stages (56 PD, 53 MSA, 23 PSP). The movement time (MT) for the standardized movement and its different components was measured. The discriminating abilities of individual, or combinations of, test variables were determined by forward stepwise multiple logistic regression and evaluated with receiver-operating characteristic (ROC) analysis. Each PLM variable separated healthy persons from patients with Parkinsonism before administration of L-DOPA (area under the curve (AUC) = 0.94-0.99, p < .001 for any separate variable). A combination of (MToff - MTon)/MToff and MTon had the highest ability to separate patients with PD from patients with atypical Parkinsonism (area under the curve = 0.91, p < .001). The PLM test discriminates between healthy controls and patients with Parkinsonism, and between patients with Parkinson's disease and patients with atypical Parkinsonism.
Asunto(s)
Movimiento/fisiología , Trastornos Parkinsonianos/fisiopatología , Anciano , Antiparkinsonianos/uso terapéutico , Diagnóstico Diferencial , Femenino , Humanos , Levodopa/uso terapéutico , Modelos Lineales , Modelos Logísticos , Masculino , Persona de Mediana Edad , Atrofia de Múltiples Sistemas/diagnóstico , Atrofia de Múltiples Sistemas/fisiopatología , Trastornos Parkinsonianos/diagnóstico , Postura/fisiología , Curva ROC , Reproducibilidad de los Resultados , Parálisis Supranuclear Progresiva/diagnóstico , Parálisis Supranuclear Progresiva/fisiopatologíaRESUMEN
Landfills have historically been seen as the ultimate solution for storing waste at minimum cost. It is now a well-known fact that such deposits have related implications such as long-term methane emissions, local pollution concerns, settling issues and limitations on urban development. Landfill mining has been suggested as a strategy to address such problems, and in principle means the excavation, processing, treatment and/or recycling of deposited materials. This study involves a literature review on landfill mining covering a meta-analysis of the main trends, objectives, topics and findings in 39 research papers published during the period 1988-2008. The results show that, so far, landfill mining has primarily been seen as a way to solve traditional management issues related to landfills such as lack of landfill space and local pollution concerns. Although most initiatives have involved some recovery of deposited resources, mainly cover soil and in some cases waste fuel, recycling efforts have often been largely secondary. Typically, simple soil excavation and screening equipment have therefore been applied, often demonstrating moderate performance in obtaining marketable recyclables. Several worldwide changes and recent research findings indicate the emergence of a new perspective on landfills as reservoirs for resource extraction. Although the potential of this approach appears significant, it is argued that facilitating implementation involves a number of research challenges in terms of technology innovation, clarifying the conditions for realization and developing standardized frameworks for evaluating economic and environmental performance from a systems perspective. In order to address these challenges, a combination of applied and theoretical research is required.
Asunto(s)
Reciclaje , Administración de Residuos , MineríaRESUMEN
There has been increased focus on recycling in Sweden during recent years. This focus can be attributed to external environmental factors such as tougher legislation, but also to the potential gains for raw materials suppliers. Recycling centres are important components in the Swedish total recycling system. Recycling centres are manned facilities for waste collection where visitors can bring, sort and discard worn products as well as large-sized, hazardous, and electrical waste. The aim of this paper was to identify and describe the main flows and layout types at Swedish recycling centres. The aim was also to adapt and apply production theory for designing and managing recycling centre operations. More specifically, this means using lean production principles to help develop guidelines for recycling centre design and efficient control. Empirical data for this research was primarily collected through interviews and questionnaires among both visitors and employees at 16 Swedish recycling centres. Furthermore, adapted observation protocols have been used in order to explore visitor activities. There was also close collaboration with a local recycling centre company, which shared their layout experiences with the researchers in this project. The recycling centres studied had a variety of problems such as queues of visitors, overloading of material and improper sorting. The study shows that in order to decrease the problems, the recycling centres should be designed and managed according to lean production principles, i.e. through choosing more suitable layout choices with visible and linear flows, providing better visitor information, and providing suitable technical equipment. Improvements can be achieved through proper planning of the layout and control of the flow of vehicles, with the result of increased efficiency and capacity, shorter visits, and cleaner waste fractions. The benefits of a lean production mindset include increased visitor capacity, waste flexibility, improved sorting quality, shorter time for visits and improved working conditions.
Asunto(s)
Eficiencia Organizacional , Arquitectura y Construcción de Instituciones de Salud/métodos , Reciclaje/métodos , Eliminación de Residuos/métodos , Entrevistas como Asunto , Reciclaje/economía , Eliminación de Residuos/economía , Encuestas y Cuestionarios , SueciaRESUMEN
This paper analyses how different actors influence the sorting quality of waste at recycling centres. Users (i.e. citizens) play an essential role since they conduct the actual sorting. They have difficulties sorting many of their discarded products, leading to decreased performance of the entire waste management system of which recycling centres are a part. Several measures addressing this problem are identified such as product design, improved terminology for labelling waste and increased manning at recycling centres. A fundamental task for managers and employees is to further develop information and guidance for users, both at home and at recycling centres. Several obstacles for improvements are also discussed, including working conditions and the economy of recycling centres, as well as the routines for communication and quality assurance among actors in the recycling business.
Asunto(s)
Eficiencia Organizacional , Eliminación de Residuos/métodos , Participación de la Comunidad , Conservación de los Recursos Naturales , Humanos , Entrevistas como Asunto , Eliminación de Residuos/normas , Encuestas y Cuestionarios , Suecia , Residuos/clasificaciónRESUMEN
Beneficial use of waste relies on efficient systems for collection and separation. In Sweden, a bring system involving recycling centres for collection of bulky, electr(on)ic and hazardous waste has been introduced. A significant share of this waste is incorrectly sorted, causing downstream environmental implications. At present, however, there is a lack of affordable and accurate monitoring methods for providing the recycling centres with the necessary facts for improving the sorting of waste. The aim of this study was therefore to evaluate the usability of a simplified and potentially more suitable waste monitoring method for recycling centres. This method is based on standardised observations where the occurrence of incorrect sorting is monitored by taking digital pictures of the waste which then are analysed according to certain guidelines. The results show that the developed monitoring method could offer a resource-efficient and useful tool for proactive quality work at recycling centres, involving continuous efforts in developing and evaluating measures for improved sorting of waste. More research is however needed in order to determine to what extent the obtained results from the monitoring method are reliable.
Asunto(s)
Conservación de los Recursos Naturales/métodos , Eliminación de Residuos/métodos , Madera/química , Aluminio/química , Monitoreo del Ambiente , Residuos Peligrosos , Industrias , Desarrollo de Programa , SueciaRESUMEN
Reuse of by-products in road construction is most often environmentally evaluated from the narrow perspective of the material itself, i.e. the material level. In this article, we argue that the current mainstream environmental evaluation of reuse of by-products in road construction should use wider system boundaries. In order to illustrate the importance of system boundaries to the final result, three additional levels that complement the material level, are applied to the environmental evaluation of reuse of by-products. In total these four levels of evaluation are, firstly, the material itself, mainly studied by leaching tests, secondly, the road environment studied by substance flow analysis, furthermore, a narrow life-cycle perspective and, finally, the industrial system level that addresses the reuse of by-products in a broader sense. Methods and tools applied to different levels emphasise different environmental aspects and consequently they are appropriate for addressing different questions. However, especially for the evaluation of environmental aspects on the industrial system level, there is a need to develop the methods. To apply these four levels to the evaluation would broaden the knowledge about the environmental impacts of the reuse of by-products. We argue that current leaching tests have to be complemented by the broader system boundaries used in substance flow studies and in life-cycle assessments in order to discuss the use of resources and environmental impacts from a wider perspective.