263 research outputs found
Cell Ultrastructure in Disease
The doctor of today must adopt the \u27cellular way of thinking\u27 in the evaluation of diseases. This ultrastructural outlook provides him with much indispensable information that also serves a practical purpose. A diseased cell organelle is at the basis of every clinical sign and any attempt of therapy must be aimed at that specific point of lesion. We intend, in the light of a long experience, to propose to clinicians a new way of thinking in which a precise correlation between symptoms and sub-microscopic changes of the cell is considered. Many different examples amply justify this proposal. Electron microscopy can contribute by enabling a) identification of structural sub-cellular modifications suitable for the finest differential diagnosis, b) more and more complete understanding of pathogenic pathways of various diseases, c) the establishment of guidelines for precise pharmacological interventions at the molecular level
A methodological approach exploiting modern techniques for forest road network planning
A well-developed road network allows all forest activities, including wood harvesting, firefighting and recreational activities. However, forest road construction and maintenance involve economic and environmental costs. For these reasons, forest road network planning is a fundamental phase of forest management, maximising the benefits and reducing costs and impacts. Thanks to modern technologies in data collection both for terrestrial and forest characteristics, new methods and tools have been developed to improve and facilitate road planning. The aim of this study was the development of a Decision Support System for helping managers during forest road network planning, exploiting Multi-Criteria Analysis, an Analytic Hierarchy Process and Geographic Information Systems. Three steps characterised the study: Þ an in-depth survey of the existing forest road network Þ an accessibility evaluation, based on a commonly applied Italian definition, taking into account the morphological characteristics of the land Þ an estimation of the accessibility requirements through the analysis of experts’ opinions, defined as Road Needs Index, based on different factors These phases were applied to a forest property located in northern Italy, and some improvements were proposed simulating a manager’s approach during planning. The results showed interesting features in accessibility evaluation, which identified three different classes of accessibility, represented in a map. The estimation of Road Needs Index assigned a class regarding road requirements to each forest management unit: »low«, »medium«, »high« and »very high«. This information was merged, becoming a useful tool to identify the forest areas with the highest problems in relation to the forest road network
Strategies to Mitigate the Effects of Soil Physical Disturbances Caused by Forest Machinery: a Comprehensive Review
Purpose of Review: Ground-based mechanized forest operations can cause severe soil disturbances that are often long lasting and detrimental to the health of forested ecosystems. To reduce these soil disturbances, focus is being increasingly directed at identifying and using appropriate mitigation techniques. This systematic review considered 104 scientific articles and reported the main findings according to four core themes: terrain-related factors, operational planning, machine modifications, and types of amendments used to mitigate machine-induced soil impacts. Recent Findings: For terrain-related factors, most severe disturbances occur on machine operating trails exceeding 20% slope and that soil bulk density and rut depth show greater increases in fine-textured soils. When considering operational planning, trafficability maps proved to be helpful in reducing the frequency and magnitude of soil damages as well as the length of trails needed within harvest sites, especially if they are regularly updated with weather information. Machine modifications, through high flotation tires, use of extra bogie axle, lower inflation pressure, and use of steel flexibles tracks, are highly researched topics because of the considerable upside in terms of machine ground pressure distribution and increased traction. Two main types of amendments emerged to mitigate soil disturbances: brush mats and mulch cover. Brush mats created from harvesting debris can spread the load of a machine to a greater area thereby lowering peak loads transferred to the soil. Brush mats of 15–20 kg m−2 are being recommended for adequate soil protection from harvesting operations. Summary: To conclude, we outline recommendations and strategies on the use of soil mitigation techniques within cut-to-length forest operations. New research opportunities are also identified and discussed. Considering single factors causing machine-induced soil disturbances remains important but there is a pressing need for having a multi-disciplinary approach to tackle the complex problems associated with machine/soil/plant interactions
Determining noise and vibration exposure in conifer cross-cutting operations by using Li-Ion batteries and electric chainsaws
In many activities, chainsaw users are exposed to the risk of injuries and several other hazard factors that may cause health problems. In fact, environmental and working conditions when using chainsaws result in workers' exposure to hazards such as noise, vibration, exhaust gases, and wood dust. Repeated or continuous exposure to these unfavourable conditions can lead to occupational diseases that become apparent after a certain period of time has elapsed. Since the use of electric tools is increasing in forestry, the present research aims to evaluate the noise and vibration exposure caused by four models of electric chainsaws (Stihl MSA160T, Stihl MSA200C Li-Ion battery powered and Stihl MSE180C, Stihl MSE220C wired) during cross-cutting. Values measured on the Stihl MSA160T chainsaw (Li-Ion battery) showed similar vibration levels on both right and left handles (0.9-1.0 m s-2, respectively) and so did the other battery-powered chainsaw, the Stihl MSA200C (2.2-2.3 m s-2 for right and left handles, respectively). Results showed a range of noise included between 81 and 90 dB(A) for the analysed chainsaws. In conclusion, the vibrations and noise were lower for the battery chainsaws than the wired ones, but, in general, all the values were lower than those measured in previous studies of endothermic chainsaws
Corsican pine (Pinus laricio Poiret) stand management: Medium and long lasting effects of thinning on biomass growth
With the aim of acquiring better comprehension of the ecological and productive aspects of the management of pine forests, we monitored logging damage and evaluated the effects of thinning on stand growth 20 years after the treatment in a Pinus laricio Poiret stand in central Italy. The objectives of the present study were to estimate the injury levels to the remaining trees after thinning; to assess logging damage in the long-term by monitoring residual trees at the end of thinning; to evaluate the effect of damage on the radial growth of trees; to assess the stand dynamics in relation to injury levels and the treatment applied in a twenty-year range; to understand a possible treatment return time; and to evaluate the existence of the "thinning shock". The results were that 20 years after treatment, the stand dynamics showed a complete recovery; logging damage did not affect the radial growth of P. laricio over time; a second treatment seem to be sustainable starting from the fifteenth year after the previous treatment; and the thinning shock can be clearly evaluated in the first six to seven years after the treatment
Forest road planning, construction and maintenance to improve forest fire fighting: A review
Forest roads play a key-role in fire fighting activities. In fact, all ground-based activities are strictly related to the presence of forest roads as access to fire edge. In spite of this important role, forest roads are often planned and built without considering their use in fire fighting, and this also occurs in literature, where few studies are dedicated to the importance of forest roads in fire fighting. A well-developed and well-maintained forest road network is the answer to different needs in fire management. The objective of this review is to clarify basic principles for obtaining efficient road network also for fire fighting, collecting, defining and resuming the main roles, the most important aspects and the reported experiences to be taken into account in forest road network planning and maintenance in fire-prone areas. The most important themes treated are related to: i) the analysis of the functions of forest roads in fire prevention and suppression; ii) the importance of forest road planning and building also considering their importance for protecting forests against fires: iii) the construction and maintenance characteristics to be considered for building and maintaining an efficient forest road network against fires; iv) the importance of fire prevention and the related role of forest roads. Special attention has been dedicated to maintenance activities, because a not well-maintained forest road is a not efficient forest road, and it represents a useless economic and environmental cost
Impact assessment of skidding extraction: Effects on physical and chemical properties of forest soils and on maple seedling growing along the skid trail
Several studies investigated soil disturbances caused on skid trails by forest logging. However, there is still a lack of knowledge about the severity and the distance of disturbances along both sides from the trails. The aims of this study were: i) to investigate the changes in physical and chemical properties of soil along the sides of skidding trails; ii) to measure the effects of soil compaction on of maple seedlings growth. Two levels of trail gradient ( < 20% and > 20 %), four levels of traffic frequency (3, 8, 15, and 30 passes) and four distance buffer strip zones (0.5 m intervals from 0 to 2 m in distance) on both sides of skid trail edges were analyzed. Each treatment included three replicate plots. In order to investigate the effect of compaction on seedlings emergence and growth, maple seeds were sown after logging. The results highlighted significant changes in physical and chemical properties of soil for each traffic frequency in the closest buffer strip (from 0 to 0.5 m from the skid trail edges). The largest changes in soil properties were identified at 0.5 m distance zones for a slope gradient > 20% after 3, 8, 15, and 30 skidding cycles. The highest changes were recorded on slope category > 20%. The higher the soil compaction the lower the germination rate, root length, and stem height of seedlings
Considerations on forest road networks and related works to support the implementation of the operative guidelines of the consolidate law on forests and forest chains
Diradamenti e fuoco prescritto per la prevenzione degli incendi in rimboschimenti di pino d’Aleppo
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