Destino no ambiente e comportamento agronômico de atrazina em resposta a doses e níveis de palha de espécies de cobertura de solo

The use of cover crops is a fundamental strategy to the weed management in Southern Brazil. In highly infested areas, the herbicides use is increasing, which increases the costs of the crops production as well as the environmental contamination. Oat and velvet bean plants havecontrasting characteristics regarding to residues decomposition speed and the capacity to immobilize Nitrogen in the soil, providing distinct results of weeds suppression throughout the time, and therefore, requiring distinct management strategies before, during, and after the corn crop establishment. The general objective of the experiment was to evaluate the environmental dynamics of the herbicide atrazine, the corn grain yield, and the efficiency of the weed control, considering areas with distinct history regarding the use of mulching, levels of straw and rates of atrazine. For this, the experiment was carried out in two parts: in the first part, two trials with the corn crop were established, one using oat and the other using velvet bean as cover crops. The experimental design used for both field trials was randomized complete blocks arrangement with four replications. The factor A was constituted by four levels of straw (0; 0.75x; 1.5x; 3x) and the factor B was constituted by four rates of the herbicide atrazine (0; 2100; 4200; 8400 g a i. ha-1). Soil samples were collected for greenhouse trialsto determine the persistence. Atrazine leaching evaluation was performed by chromatography using samples collected over the soil profile.In the field, the weed density, the fresh and dry weight and the yield of the corn were evaluated. In the greenhouse trials, the main variables evaluated were plant height and injury caused by the herbicide toxicity. In the second part, soils with distinct covering history were sampled, and the mineralization and sorption studies, both with 14C-atrazine, were conducted in the laboratory. The experimental design was randomized complete blocks arrangement with four replications. The results from the field experiment show that the high levels of straw above ground, isolated, were not efficient to control completely the weeds, and that high levels of velvet bean`s straw decreased the corn potential yield. The greenhouse trials showed that high levels of oat straw prevent the scape of atrazine to soil, this effect of oat straw upon the herbicide availability on soil was detected up to 12 days after spraying. The half-life of atrazine sprayed over oat straw varied from 7 to 14 days after spraying, while the half-life of atrazine sprayed over velvet bean varied from 5 to 14 days after spraying. Increasing oat straw levels presents the capacity to reduce the lixiviation of atrazine in the soil profile, however, this effect was not verified when using velvet bean straw, because the herbicide was not detected in the soil profile, at 21 days after spraying. The chromatographic analysis indicate thatthe atrazine concentrates closer to the soil surface regardless of amount of straw, not being detected deeper than 8 cm in the soil. The accumulated mineralization of 14C-arazine sprayed over V. sativa is superior if compared to soils with S. cereale or non-covered soils. The sorption coefficient of atrazine is superior when sprayed over straw than over the soil.

Programa ciclovida como política de mobilidade urbana sustentável: estudo empírico na Universidade Federal do Paraná

The urban mobility has in the bicycle its symbol of the most environmentally sustainable modal of transportation of the planet, title conferred by the United Nations Organization (ONU). Nevertheless, the cities suffer with the traffic jam caused by the automobile fleet growth, what implies in a larger displacement time, injuries to the environment, to financials and to the quality of life. In order to build in a sustainable way the urban mobility, public policies are necessary to encourage the preferential usage, by the society, of the mass transit or the non-motorized type of transportation. Objecting cooperate with the public power and the civil society, this study intents to, through an analysis about the UFPR Extension Program - CICLOVIDA, propose a sustainable urban mobility public policy development, with emphasis in the bicycle´s usage. eferentially, it is discussed concepts such as Society, State and Government as well as public policies, which go in cycles to the State´s and Government´s responsibilities; and are presented the Sustainable Urban Mobility Public Policies (PPMUS) in Brazil. Also, it is debated about the transport by bicycle as an option to the sustainable mobility. Methodologically, the study is of an empiric-social nature, with the application of both qualitative and observational methods, what characterizes as an exploratory level of research, with the researcher´s involvement in the participant form, due to her acting on the Program. Regarding the research lineation, it was used the bibliographic and documental form as well as case study, by means of the nonparametric sampling by accessibility or convenience. Related to the data collection technique, it was used structured interviews with self-applied questionnaires and natural participant observation. Aligned with the research´s objective and matter, the outcome confirmed that the Extension Program CICLOVIDA of the Federal University of Paraná (UFPR) may effectively contribute in the development of a PPMUS proposal with emphasis in the bicycle usage. Thus, it was built a political proposal with a free form writing, objecting subsidize policies both institutional as public MUS through the bicycle usage and therefore, support the mobility, also contributing to the sustainability and to the public development planning.

Programa Etnomatemática: ponderações da prática pedagógica

The aim of this present work is investigating the interest and motivation for learning, awakened in pupils when the educator practice is guided by the ethnomathematics perspective. The main question is: Can an ethnomathematic approach awaken enthusiasm in pupils, causing it to become more critic and active in building their knowledge? The methodology that guides the investigation is qualitative, based on technical arising of the ethnographic case study. Theoretical contributions that support the investigation are from the scientific methodology and from ethnomathematics. The research material is composed by: researcher’s field diary, audio recording of participant observation, interviews reports of community residents and students parents, highlighting the material produced by students. This study was developed on an 8º year of high school of rural community. During the work were prioritized the ethnomathematics concepts of the Ethnomathematic Program, which establish a link exchange, where the lecturers inserts themselves on the reality of pupils in a way that promote an appreciation of their identity and a commitment to their learning. The educator investigates and values the ideas of pupils throughout dialogues. There are challenges for the application of education with ethno mathematic perspective, pointed out by authors, listed and supplemented in the research. In this context, it is believed that the socio-cultural knowledge must be respect, and as they are understood their specialties, capabilities and characteristics, this can guide teaching practice, making significant process for pupils, providing appropriation of scientific knowledge. Analysis of research practice indicated that students, research subjects, when they decided contextual issues, with their way of life, felt appreciated. The conclusion is that, with continuous action of contextualized of school mathematics, from the recognition of the environment and of cultural identity, the educator has the opportunity of review their own participant condition, and therefore promote an enthusiasm for learning. Because a motivated pupil becomes active, since that the all project is guided in a significant theme.