983 resultados para Stiffness of the aggregate


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Sectoral policies make explicit and implicit assumptions about the behaviour and capabilities of the agents (such as dynamic responses to market signals, demand-led assistance, collaborative efforts, participation in financing); which we consider to be rather unrealistic. Because of this lack of realism, policies that aim to be neutral often turn out to be highly exclusive. They fail to give sufficient importance to the special features of the sector -with its high climatic, biological and commercial risks and its slow adaptation- or to the fact that those who take decisions in agriculture are now mostly in an inferior position because of their incomes below the poverty line, their inadequate training, their traditions based on centuries of living in precarious conditions, and their geographical location in marginal areas, far from infrastructure and with only a minimum of services and sources of information. These people have only scanty and imperfect access to the markets which, according to the prevailing model, should govern decisions and the (re);distribution of the factors of production. In our opinion, this explains the patchy and lower-than-expected growth registered by the sector after the reforms to promote the liberalization of markets and external openness in the region. In view of the results of the application of the new model, it may be wondered whether Latin America can afford a form of development which excludes over half of its agricultural producers; what the alternatives are; and what costs and benefits each of them offers in terms of production and monetary, social, spatial and other aspects. The article outlines the changes in policies and their results at the aggregate level, summarizes the arguments usually put forward to explain agricultural performance in the region, and proposes a second set of explanations based on a description of the agents and the responses that may be expected from them, contrasting the latter with the supposedly neutral nature of the policies.

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The main objective of the present study was to determine the value of impacts due to climate change on the agricultural sector in the Caribbean under the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios A2 and B2 scenarios. More specifically, the study aimed to evaluate the direction and magnitude of the potential impacts of climate change on aggregate agricultural output and other key agricultural indicators. Further, the study forecast changes in income for agricultural output for key subsectors under the A2 and B2 scenarios, from 2011 to 2050. It analysed the benefits and costs of the key adaptation strategies identified by Caribbean Governments.

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This report analyses the agriculture, health and tourism sectors in Saint Lucia to assess the potential economic impacts of climate change on the sectors. The fundamental aim of this report is to assist with the development of strategies to deal with the potential impact of climate change in Saint Lucia. It also has the potential to provide essential input for identifying and preparing policies and strategies to help advance the Caribbean subregion closer to solving problems associated with climate change and attaining individual and regional sustainable development goals. Some of the key anticipated impacts of climate change for the Caribbean include elevated air and sea-surface temperatures, sea-level rise, possible changes in extreme events and a reduction in freshwater resources. The economic impact of climate change on the three sectors was estimated for the A2 and B2 IPCC scenarios until 2050. An evaluation of various adaptation strategies for each sector was also undertaken using standard evaluation techniques. The key subsectors in agriculture are expected to have mixed impacts under the A2 and B2 scenarios. Banana, fisheries and root crop outputs are expected to fall with climate change, but tree crop and vegetable production are expected to rise. In aggregate, in every decade up to 2050, these sub-sectors combined are expected to experience a gain under climate change with the highest gains under A2. By 2050, the cumulative gain under A2 is calculated as approximately US$389.35 million and approximately US$310.58 million under B2, which represents 17.93% and 14.30% of the 2008 GDP respectively. This result was unexpected and may well be attributed to the unavailability of annual data that would have informed a more robust assessment. Additionally, costs to the agriculture sector due to tropical cyclones were estimated to be $6.9 million and $6.2 million under the A2 and B2 scenarios, respectively. There are a number of possible adaptation strategies that can be employed by the agriculture sector. The most attractive adaptation options, based on the benefit-cost ratio are: (1) Designing and implementation of holistic water management plans (2) Establishment of systems of food storage and (3) Establishment of early warning systems. Government policy should focus on the development of these adaption options where they are not currently being pursued and strengthen those that have already been initiated, such as the mainstreaming of climate change issues in agricultural policy. The analysis of the health sector placed focus on gastroenteritis, schistosomiasis, ciguatera poisoning, meningococal meningitis, cardiovascular diseases, respiratory diseases and malnutrition. The results obtained for the A2 and B2 scenarios demonstrate the potential for climate change to add a substantial burden to the health system in the future, a factor that will further compound the country’s vulnerability to other anticipated impacts of climate change. Specifically, it was determined that the overall Value of Statistical Lives impacts were higher under the A2 scenario than the B2 scenario. A number of adaptation cost assumptions were employed to determine the damage cost estimates using benefit-cost analysis. The benefit-cost analysis suggests that expenditure on monitoring and information provision would be a highly efficient step in managing climate change and subsequent increases in disease incidence. Various locations in the world have developed forecasting systems for dengue fever and other vector-borne diseases that could be mirrored and implemented. Combining such macro-level policies with inexpensive micro-level behavioural changes may have the potential for pre-empting the re-establishment of dengue fever and other vector-borne epidemic cycles in Saint Lucia. Although temperature has the probability of generating significant excess mortality for cardiovascular and respiratory diseases, the power of temperature to increase mortality largely depends on the education of the population about the harmful effects of increasing temperatures and on the existing incidence of these two diseases. For these diseases it is also suggested that a mix of macro-level efforts and micro-level behavioural changes can be employed to relieve at least part of the threat that climate change poses to human health. The same principle applies for water and food-borne diseases, with the improvement of sanitation infrastructure complementing the strengthening of individual hygiene habits. The results regarding the tourism sector imply that the tourism climatic index was likely to experience a significant downward shift in Saint Lucia under the A2 as well as the B2 scenario, indicative of deterioration in the suitability of the island for tourism. It is estimated that this shift in tourism features could cost Saint Lucia about 5 times the 2009 GDP over a 40-year horizon. In addition to changes in climatic suitability for tourism, climate change is also likely to have important supply-side effects on species, ecosystems and landscapes. Two broad areas are: (1) coral reefs, due to their intimate link to tourism, and, (2) land loss, as most hotels tend to lie along the coastline. The damage related to coral reefs was estimated at US$3.4 billion (3.6 times GDP in 2009) under the A2 scenario and US$1.7 billion (1.6 times GDP in 2009) under the B2 scenario. The damage due to land loss arising from sea level rise was estimated at US$3.5 billion (3.7 times GDP) under the A2 scenario and US$3.2 billion (3.4 times GDP) under the B2 scenario. Given the potential for significant damage to the industry a large number of potential adaptation measures were considered. Out of these a short-list of 9 potential options were selected by applying 10 evaluation criteria. Using benefit-cost analyses 3 options with positive ratios were put forward: (1) increased recommended design speeds for new tourism-related structures; (2) enhanced reef monitoring systems to provide early warning alerts of bleaching events, and, (3) deployment of artificial reefs or other fish-aggregating devices. While these options had positive benefit-cost ratios, other options were also recommended based on their non-tangible benefits. These include the employment of an irrigation network that allows for the recycling of waste water, development of national evacuation and rescue plans, providing retraining for displaced tourism workers and the revision of policies related to financing national tourism offices to accommodate the new climate realities.

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The aim of this ex vivo study was to evaluate, by scanning electron microscopy (SEM), the presence of gaps at the interface between filling material and three root-end filling materials. Thirty human upper molars disto-buccal roots were instrumented and filled with gutta-percha and eugenol-based sealer. The apicoectomy was performed 2mm from the apex and retrograde cavities were prepared with ultrasonic points (3mm in deep). The samples were divided into three experimental groups (n=10): Group Iwhite mineral trioxide aggregate (MTA); Group IISuper EBA; and Group IIIPortland cement. The root-end filling materials were inserted into the retocavities using a MTA carrier. After 48h, the roots were transversally sectioned in order to obtain the apical 5mm. Next, each specimen was prepared longitudinally with crescent granulation of abrasives water-wet sandpapers in order to expose the filling and root-end filling materials. Then, the specimens were subjected to slow dehydration with silica gel, mounted onto specific stubs and coated with paladium coverage for SEM analysis of the interface between filling and root-end filling materials. The percentage of gaps at the interfacial area was calculated by using Image Tool 3.0 software. Super EBA presented the higher percentage of gaps (1.5 +/- 0.67%), whereas MTA presented the lowest values (0.33 +/- 0.20%; p=0.0004). Despite the statistical differences observed between Super EBA and MTA, all the root-end filling materials presented great adaptation to the filling material, presenting small amount of gaps. SCANNING 36:252-257, 2014. (c) 2013 Wiley Periodicals, Inc.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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A variety of platinum-group-minerals (PGM) have been found to occur associated with the chromitite and dunite layers in the Niquelandia igneous complex. Two genetically distinct populations of PGM have been identified corresponding to phases crystallized at high temperatures (primary), and others formed or modified during post-magmatic serpentinization and lateritic weathering (secondary). Primary PGM have been found in moderately serpentinized chromitite and dunite, usually included in fresh chromite grains or partially oxidized interstitial sulfides. Due to topographically controlled lateritic weathering, the silicate rocks are totally transformed to a smectite-kaolinite-garnierite-amorphous silica assemblage, while the chromite is changed into a massive aggregate of a spinel phase having low-Mg and a low Fe3+/Fe2+ ratio, intimately associated with Ti-minerals, amorphous Fe-hydroxides, goethite, hematite and magnetite. The PGM in part survive alteration, and in part are corroded as a result of deep chemical weathering. Laurite is altered to Ru-oxides or re-crystallizes together with secondary Mg-ilmenite. Other PGM, especially the Pt-Fe alloys, re-precipitate within the altered chromite together with kaolinite and Fe-hydroxides. Textural evidence suggests that re-deposition of secondary PGM took place during chromite alteration, controlled by variation of the redox conditions on a microscopic scale.

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Aim To evaluate the inflammatory process induced by Biodentine and mineral trioxide aggregate (MTA) in rat subcutaneous tissues. Methodology A polyethylene tube filled with Biodentine (n = 20) or MTA (n = 20) was placed into the dorsal subcutaneous of forty male rats; in the control group (CG; n = 20), empty tubes were implanted. After 7, 15, 30 and 60 days, the polyethylene tubes surrounded by connective tissue were fixed and embedded in paraffin. The number of inflammatory cells was estimated in HE-stained sections; numerical density of interleukin-6 (IL-6)-immunolabelled cells was also performed. The differences amongst the groups were analysed statistically by Tukey's test (P ≤ 0.05). Results A high number of inflammatory cells and IL-6-positive cells were observed at 7 days, in all groups; however, in the Biodentine group, the number of inflammatory cells and IL-6-immunolabelled cells was significantly higher (P ≤ 0.05) in comparison with the other groups at 7 and 15 days. In the capsules of animals from all groups, a gradual and significant reduction (P ≤ 0.05) of these parameters was seen over time. At 60 days, the capsules exhibited numerous fibroblasts and bundles of collagen fibres; in addition, the number of IL-6-positive cells was not significantly different amongst Biodentine, MTA and control groups. Conclusions There was a significant regression in the inflammatory reaction in the capsules indicating, therefore, that Biodentine is a biocompatible material.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This study aimed to investigate the influence of storage time (0, 48 hours) of Pinus elliottii pieces and the tests to obtaining modulus of elasticity (static bending and transversal vibration) in glued laminated timber beams, produced with resorcinol based adhesive and 0.8 MPa compaction pressure. After pieces were properly prepared, part of them was used in immediate three manufacturing glulam beams, tested after adhesive cure, and part stored for 48 hours under a roof with a temperature of 25°C and relative humidity of 60% for subsequent manufacturing and testing three other glulam beams. Results of analysis of variance (ANOVA) revealed that the storage period was significant influence in modulus of elasticity obtained in static bending test (8% reduction from 0 to 48 hours). This not occurred with modulus of elasticity obtained by transversal vibration test (no significant influence). ANOVA results showed equivalence of means in both test procedures. New researches ire needed to better understand the investigated phenomenon, using new wood species, other storage conditions and a great number of samples.

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Pós-graduação em Cirurgia Veterinária - FCAV

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The Bernoulli's model for vibration of beams is often used to make predictions of bending modulus of elasticity when using dynamic tests. However this model ignores the rotary inertia and shear. Such effects can be added to the solution of Bernoulli's equation by means of the correction proposed by Goens (1931) or by Timoshenko (1953). But to apply these corrections it is necessary to know the E/G ratio of the material. The objective of this paper is the determination of the E/G ratio of wood logs by adjusting the analytical solution of the Timoshenko beam model to the dynamic testing data of 20 Eucalyptus citriodora logs. The dynamic testing was performed with the logs in free-free suspension. To find the stiffness properties of the logs, the residue minimization was carried out using the Genetic Algorithm (GA). From the result analysis one can reasonably assume E/G = 20 for wood logs.

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Bertuzzi, R, Bueno, S, Pasqua, LA, Acquesta, FM, Batista, MB, Roschel, H, Kiss, MAPDM, Serrao, JC, Tricoli, V, and Ugrinowitsch, C. Bioenergetics and neuromuscular determinants of the time to exhaustion at velocity corresponding to (V) over dotO(2)max in recreational long-distance runners. J Strength Cond Res 26(8): 2096-2102, 2012-The purpose of this study was to investigate the main bioenergetics and neuromuscular determinants of the time to exhaustion (T-lim) at the velocity corresponding to maximal oxygen uptake in recreational long-distance runners. Twenty runners performed the following tests on 5 different days: (a) maximal incremental treadmill test, (b) 2 submaximal tests to determine running economy and vertical stiffness, (c) exhaustive test to measured the T-lim, (d) maximum dynamic strength test, and (e) muscle power production test. Aerobic and anaerobic energy contributions during the T-lim test were also estimated. The stepwise multiple regression method selected 3 independent variables to explain T-lim variance. Total energy production explained 84.1% of the shared variance (p = 0.001), whereas peak oxygen uptake ((V) over dotO(2)peak) measured during T-lim and lower limb muscle power ability accounted for the additional 10% of the shared variance (p = 0.014). These data suggest that the total energy production, (V) over dotO(2)peak, and lower limb muscle power ability are the main physiological and neuromuscular determinants of T-lim in recreational long-distance runners.

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Surface treatment interferes with the primary stability of dental implants because it promotes a chemical and micromorphological change on the surface and thus stimulates osseointegration. This study aimed to evaluate the effects of different surface treatments on primary stability by analyzing insertion torque (IT) and pullout force (PF). Eight samples of implants with different surface treatments (TS - external hexagon with acid surface treatment; and MS - external hexagon, machined surface), all 3.75 mm in diameter x 11.5 mm in length, were inserted into segments of artificial bones. The IT of each sample was measured by an electronic torquemeter, and then the pullout test was done with a universal testing machine. The results were subjected to ANOVA (p < 0.05), followed by Tukey's test (p < 0.05). The IT results showed no statistically significant difference, since the sizes of the implants used were very similar, and the bone used was not highly resistant. The PF values (N) were, respectively, TS = 403.75 +/- 189.80 and MS = 276.38 +/- 110.05. The implants were shown to be different in terms of the variables of maximum force (F = 4.401, p = 0.0120), elasticity in maximum flexion (F = 3.672, p = 0.024), and relative stiffness (F = 4.60, p = 0.01). In this study, external hexagonal implants with acid surface treatment showed the highest values of pullout strength and better stability, which provide greater indication for their use.