966 resultados para wood alternatives
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This paper presents the preliminary findings of pH and colour measurements carried out on artworks on paperand on wood that had been treated with a poly(vinyl acetate) (PVAC) based adhesive in the 1980s. In both cases, areas treated with PVAC proved to be less acidic than untreated areas. Contrary to expectations, the conservation treatments have not, as yet, increased acidity levels in the objects under study. Colour measurements of the works on paper showed that those that had been backed with a cotton fabric using a mixture of methylcellulose and PVAC were less yellow than those from the same print run that had not been backed. This finding suggests that the backing somehow prevented the natural degradation of the support. In view of these preliminary results, further research is clearly needed. This study forms part of a broader ongoing project to assess the role of PVAC in the conservation of a range of cultural assets.
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This document produced bu Iowa State University and Iowa Department of Natural Resources shows the key identification of Common Woods in Iowa.
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1. Wood ants (Formica paralugubris) incorporate large amounts of solidified conifer resin into their nest, which reduces the density of many bacteria and fungi and protects the ants against some detrimental micro-organisms. By inducing an environment unfavourable to pathogens, the presence of resin may allow workers to reduce the use of their immune system. 2. The present study tested the hypothesis that the presence of resin decreases the immune activity of wood ants. Specifically, three components of the humoral immune defences of workers kept in resin-rich and resin-free experimental nests (antibacterial, lytic, and prophenoloxidase activities) were compared. 3. The presence of resin was associated with reduced bacterial and fungal densities in nest material and with a small decrease in worker antibacterial and lytic activities. The prophenoloxidase activity was very low in all workers and was not affected by the presence of resin. 4. These results suggest that collective medication with resin reduces pathogen pressure, which in turn decreases the use of the inducible part of the immune system. More generally, the use of plant secondary compounds might be an efficient and economical way to fight pathogens.
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Iowa’s three million acres of forest land provide environmental benefits to all Iowans in terms of soil erosion control, air quality, and water quality. In 2013, more than 6.5 million trees died. Within those trees there were more than 125 million board feet of wood, compared to 98 million board feet of wood harvested. This level of mortality is the highest level reported from US Forest Service inventories in twenty years. This is disturbing when considering more than 18,000 Iowans are employed in the wood products and manufacturing industry, generating nearly $4 billion in annual sales, more than $900 million in annual payroll and more than $25 million to private woodland owners annually from the sale of timber.
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The objective of this report is to gain a better understanding of the wood waste market in Iowa through surveying the processors of wood waste. A survey was sent out by the Iowa Department of Natural Resources Management Assistance Division to 147 public waste management organizations and private businesses with a questionnaire which asked for details of any wood waste processing operation.
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Wood ant species show differences in their social structure, especially in the level of polygyny (number of laying queens per nest) and polydomy (number of nest per colony), both within and between species. We demonstrate here for the first time that Formica lugubris displays two different social forms in close proximity in alpine unmanaged forests of the Swiss National Park. The genetic data (7 microsatellite loci) and field data indicate that one population is mostly monogynous to weakly polygynous (r = 0.438) and monodomous, the second one being polygynous (r = 0.113) and polydomous. Within this latter population new nests are founded by budding, leading to the observed high density of nests. These two different social structures, possibly being two expressions of a same continuum, could be explained by several ecological or environmental factors (e.g. habitat saturation, resource competition) and also historical effects.
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The goals of this project were to implement several stabilization methods for preventing or mitigating freeze-thaw damage to granular surfaced roads and identify the most effective and economical methods for the soil and climate conditions of Iowa. Several methods and technologies identified as potentially suitable for Iowa were selected from an extensive analysis of existing literature provided with Iowa Highway Research Board (IHRB) Project TR-632. Using the selected methods, demonstration sections were constructed in Hamilton County on a heavily traveled two-mile section of granular surfaced road that required frequent maintenance during previous thawing periods. Construction procedures and costs of the demonstration sections were documented, and subsequent maintenance requirements were tabulated through two seasonal freeze-thaw periods. Extensive laboratory and field tests were performed prior to construction, as well as before and after the two seasonal freeze-thaw periods, to monitor the performance of the demonstration sections. A weather station was installed at the project site and temperature sensors were embedded in the subgrade to monitor ground temperatures up to a depth of 5 ft and determine the duration and depths of ground freezing and thawing. An economic analysis was performed using the documented construction and maintenance costs, and the estimated cumulative costs per square yard were projected over a 20-year timeframe to determine break-even periods relative to the cost of continuing current maintenance practices. Overall, the sections with biaxial geogrid or macadam base courses had the best observed freeze-thaw performance in this study. These two stabilization methods have larger initial costs and longer break-even periods than aggregate columns, but counties should also weigh the benefits of improved ride quality and savings that these solutions can provide as excellent foundations for future paving or surface upgrades.
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Restrenyiment i teràpies alternatives i complementàries és la base de la intervenció en persones grans, sent el grup de població amb més incidència de patir restrenyiment. En elles s’hi atribueixen factors de risc força recurrents: immobilitat, polifarmàcia, dieta pobra en fibra, ingesta hídrica inadequada, etc. L’objectiu de la realització del treball és millorar el restrenyiment a través de l’aplicació de les teràpies alternatives i complementàries en persones grans institucionalitzades per tal d’aconseguir una millora del problema de salut i de la qualitat de vida mitjançant un tractament no farmacològic. El/la professional d’infermeria durà a terme la intervenció a partir d’un canvi en la dieta de la persona gran tot augment el seu contingut en fibra, potenciant la ingesta hídrica, l’aplicació de la fitoteràpia, la recomanació de la reflexologia podal, incrementar l’activitat física i la realització de tècniques de relaxació i de massatges abdominals per disminuir l’angoixa que aquest problema de salut genera a la persona i millorar el dolor abdominal que li comporta. El pla de cures d’infermeria es desenvoluparà en 12 setmanes consecutives en les quals s’aplicaran i s’avaluaran les diferents teràpies naturals de forma setmanal per poder observar l’evolució de la persona respecte a les activitats programades. Per últim, esmentar que durant tot el treball s’ha contrastat l’evidència científica de diversos autors especialitzats en el restrenyiment i en les teràpies alternatives i complementàries. La cerca de tota la informació s’ha realitzat a partir de diverses bases de dades tot aplicant els criteris d’inclusió i exclusió que m’han permès l’obtenció d’articles, llibres, guies i protocols vàlids per utilitzar-los i plasmar-los en el treball.
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