8 resultados para soil resistance to penetration
em Repositório da Produção Científica e Intelectual da Unicamp
Resumo:
This paper presents two techniques to evaluate soil mechanical resistance to penetration as an auxiliary method to help in a decision-making in subsoiling operations. The decision is based on the volume of soil mobilized as a function of the considered critical soil resistance to penetration in each case. The first method, probabilistic, uses statistical techniques to define the volume of soil to be mobilized. The other method, deterministic, determines the percentage of soil to be mobilized and its spatial distribution. Both cases plot the percentage curves of experimental data related to the soil mechanical resistance to penetration equal or larger to the established critical level and the volume of soil to be mobilized as a function of critical level. The deterministic method plots showed the spatial distribution of the data with resistance to penetration equal or large than the critical level. The comparison between mobilized soil curves as a function of critical level using both methods showed that they can be considered equivalent. The deterministic method has the advantage of showing the spatial distribution of the critical points.
Resumo:
The syndrome of resistance to thyroid hormone (RTH β) is an inherited disorder characterized by variable tissue hyposensitivity to 3,5,30-l-triiodothyronine (T3), with persistent elevation of free-circulating T3 (FT3) and free thyroxine (FT4) levels in association with nonsuppressed serum thyrotropin (TSH). Clinical presentation is variable and the molecular analysis of THRB gene provides a short cut diagnosis. Here, we describe 2 cases in which RTH β was suspected on the basis of laboratory findings. The diagnosis was confirmed by direct THRB sequencing that revealed 2 novel mutations: the heterozygous p.Ala317Ser in subject 1 and the heterozygous p.Arg438Pro in subject 2. Both mutations were shown to be deleterious by SIFT, PolyPhen, and Align GV-GD predictive methods.
Resumo:
This work was carried out with the objective of studying the spatial variability of the physical attributes of a Red-Yellow Ultisol under pasture and secondary vegetation in natural regeneration. Two areas were chosen in a hillside, with the soil sampling to the depth of 0-0.2 m, with the georeferenced points in a regular grid of 10x10 m, totalizing 64 points. In each point it was evaluated the total volume of porosity, macroporosity, microporosity, bulk density, soil penetration resistance and soil water content. The studied attributes in the pasture area present indicator of soil compaction for the animals' traffic, with moderate and strong structure of spatial dependence, except for the macroporosity and penetration resistance. In the area of secondary vegetation (VN) only the macroporosity does not present spatial dependence. The total volume of porosity and the bulk density present the same spatial standard in the area under pasture.
Resumo:
Mine drainage is an important environmental disturbance that affects the chemical and biological components in natural resources. However, little is known about the effects of neutral mine drainage on the soil bacteria community. Here, a high-throughput 16S rDNA pyrosequencing approach was used to evaluate differences in composition, structure, and diversity of bacteria communities in samples from a neutral drainage channel, and soil next to the channel, at the Sossego copper mine in Brazil. Advanced statistical analyses were used to explore the relationships between the biological and chemical data. The results showed that the neutral mine drainage caused changes in the composition and structure of the microbial community, but not in its diversity. The Deinococcus/Thermus phylum, especially the Meiothermus genus, was in large part responsible for the differences between the communities, and was positively associated with the presence of copper and other heavy metals in the environmental samples. Other important parameters that influenced the bacterial diversity and composition were the elements potassium, sodium, nickel, and zinc, as well as pH. The findings contribute to the understanding of bacterial diversity in soils impacted by neutral mine drainage, and demonstrate that heavy metals play an important role in shaping the microbial population in mine environments.
Resumo:
To report on the use of chronic myeloid leukemia as a theme of basic clinical integration for first year medical students to motivate and enable in-depth understanding of the basic sciences of the future physician. During the past thirteen years we have reviewed and updated the curriculum of the medical school of the Universidade Estadual de Campinas. The main objective of the new curriculum is to teach the students how to learn to learn. Since then, a case of chronic myeloid leukemia has been introduced to first year medical students and discussed in horizontal integration with all themes taught during a molecular and cell biology course. Cell structure and components, protein, chromosomes, gene organization, proliferation, cell cycle, apoptosis, signaling and so on are all themes approached during this course. At the end of every topic approached, the students prepare in advance the corresponding topic of clinical cases chosen randomly during the class, which are then presented by them. During the final class, a paper regarding mutations in the abl gene that cause resistance to tyrosine kinase inhibitors is discussed. After each class, three tests are solved in an interactive evaluation. The course has been successful since its beginning, 13 years ago. Great motivation of those who participated in the course was observed. There were less than 20% absences in the classes. At least three (and as many as nine) students every year were interested in starting research training in the field of hematology. At the end of each class, an interactive evaluation was performed and more than 70% of the answers were correct in each evaluation. Moreover, for the final evaluation, the students summarized, in a written report, the molecular and therapeutic basis of chronic myeloid leukemia, with scores ranging from 0 to 10. Considering all 13 years, a median of 78% of the class scored above 5 (min 74%-max 85%), and a median of 67% scored above 7. Chronic myeloid leukemia is an excellent example of a disease that can be used for clinical basic integration as this disorder involves well known protein, cytogenetic and cell function abnormalities, has well-defined diagnostic strategies and a target oriented therapy.
Resumo:
The aim of this research was to study the effect of chemical additives (lime and Portland cement) associated with sodium silicate on soil in order to obtain compressed soil bricks. Mini panels were constructed with such bricks being their physical and mechanical characteristics determined in laboratory conditions and their behavior evaluated through the association of destructive and non-destructive methods. For this purpose a sandy soil and a finely divided one were added to Portland cement and lime in the dosage of 6% and 10% taken in dry weight basis in relation to the dry soil. The sodium silicate dosage of 4% was also taken in dry weight basis in relation to the dry soil-cement or to the dry soil-lime. The compressed soil bricks were cured in a humidity chamber for 7; 28; 56 and 91 days. The bricks were laid on the fourteenth day to form prismatic mini panels each one with four layers of bricks. After 28; 56 and 91 days the mini panels were submitted to both; ultrasonic and compressive tests to determine its elastic properties (dynamic modulus) and the compressive resistance. The best results in terms of compressive strength, water absorption capacity or dynamic elastic modulus, were reached by the sandy soil added to 10% of Portland cement or lime associated with sodium silicate.
Resumo:
This paper presents the behavior of three bored piles conducted in diabasic soil submitted to uplift forces. The piles were built at the site for Experimental Studies in Soil Mechanics and Foundations of UNICAMP, located in the city of Campinas, Brazil. Field tests have already been conducted at the site (SPT, CPT, DMT and PMT), as well as laboratory tests by using sample soils taken from a well up to 17 m deep. The water table is not checked until a depth of 17 m. In order to check the behavior of the piles when submitted to uplift forces, slow static load tests were carried out as the recommendations of NBR 12131. The carrying capacity of these piles was also provided by means of theoretical methods, appropriate for uplift forces, and through semi-empirical methods appropriate for compression forces, considering only the portion of lateral resistance. The values estimated by using the considered methods were compared to those obtained by means of load tests. One of the tested piles was extracted from the soil to be the subject of a study on its geometry.
Resumo:
The objective of this study was to quantify the effect of plonk on compressive behavior and mechanical attributes such as consistency, optimum moisture for compaction and maximum density of a Red-Yellow Latosol (Oxisol) to evaluate the effect of plonk and compaction state in splashed particles, from Lavras (MG) region. The plonk was obtained from an artisanal sugarcane brandy alembic. Undisturbed and disturbed soil samples were collected at 0 to 3 cm and 60 to 63 cm depths. Disturbed soil samples were used for soil characterization, determination of consistence limits and Normal Proctor essay after material incubation with plonk. Undisturbed soil samples were saturated with plonk or distilled water (control) during 48 hours for testing the compressibility and resistance to splash by using simulated rainfall. The plonk altered the consistence limits of studied layers. For the 0-3 cm layer, the plonk reduced the friable range, and for the 60-63 cm layer the effect was in the opposite direction. For both layers, the plonk increased Dmax and decreased Uoptimum. Regardless of the plonk treatment, both layers presented the same load support capacity. The compaction degree of samples influenced the splash erosion. The increase of the applied pressure over the samples resulted in increase of splash material quantity. At the 60-63 cm layer, the plonk treatment reduced the splash material quantity by increasing the applied pressure, mainly when the samples were at field capacity.