Efeitos da tilápia do Nilo (Oreochromis niloticus) e do enriquecimento por nutrientes sobre a comunidade planctônica em um lago artificial no semi-árido brasileiro

The major aim of this study was to test the hypothesis that the introduction of the Nile tilapia (Oreochromis niloticus) and the enrichment with nutrients (N and P) interact synergistically to change the structure of plankton communities, increase phytoplankton biomass and decrease water transparency of a semi-arid tropical reservoir. One field experiment was performed during five weeks in twenty enclosures (8m3) to where four treatments were randomly allocated: with tilapia addition (T), with nutrients addition (NP), with tilapia and nutrients addition (T+NP) and a control treatment with no tilapia or nutrients addition (C). A two-way repeated measures ANOVA was done to test for time (t), tilapia (T) and nutrient (NP) effects and their interaction on water transparency, total phosphorus, total nitrogen, phytoplankton and zooplankton. The results show that there was no effect of nutrient addition on these variables but significant fish effects on the biomass of total zooplankton, nauplii, rotifers, cladocerans and calanoid copepods, on the biovolume of Bacillariophyta, Zygnemaphyceae and large algae (GALD ≥ 50 μm) and on Secchi depth. In addition, we found significant interaction effects between tilapia and nutrients on Secchi depth and rotifers. Overall, tilapia decreased the biomass of most zooplankton taxa and large algae (diatoms) and decreased the water transparency while nutrient enrichment increased the biomass of zooplankton (rotifers) but only in the absence of tilapia. In conclusion, the influence of fish on the reservoir plankton community and water transparency was greater than that of nutrient loading. This finding suggests that biomanipulation should be a greater priority in the restoration of eutrophic reservoirs in tropical semi-arid regions

Efeitos do enriquecimento com nutrientes (N e P) em diferentes condições de luz sobre o crescimento do fitoplâncton em um reservatório eutrófico no semi-árido brasileiro

The increasing of pollution in aquatic ecosystems in the last decades has caused an expansion of eutrophication and loss of water quality for human consumption. The increase of frequency and intensity of cyanobacteria blooms have been recognized as a major problem connected to water quality and eutrophication. The knowledge of environmental factors controlling these blooms is a key step towards the management for recovering aquatic ecosystems from eutrophic conditions. Primary productivity in aquatic ecosystems is dependent on light and nutrients availability. In the present work we evaluated the relative importance of the concentration of major nutrients, such as phosphorus and nitrogen, and light for phytoplankton growth in the main water reservoir of Rio Grande do Norte State, named Engenheiro Armando Ribeiro Gonçalves (EARG), which is an eutrophic system, dominated by potentially toxic cyanobacteria populations. Limitation of phytoplankton growth was evaluated through bioassays using differential enrichment of nutrients (N and/or P) under two light conditions (low light and high light) and monthly monitoring of chlorophyll-a and nutrients (total nitrogen and phosphorus) concentrations, and water transparency (Secchi depth) at the pelagic region. Our results confirm that EARG reservoir is an eutrophic system with a low water quality. Results of bioassays on the growth of phytoplankton limitation (N or P) were conflicting with the results predicted by the TN:TP ratios, which indicates that these ratios were not a good indicator of algal growth limitation. Nitrogen was the limiting nutrient, considering both frequency and magnitude. Light and hidrology affected phytoplankton response to nutrient enrichment. The extreme eutrophic conditions of this reservoir, dominated by cyanobacteria blooms, demand urgent managing strategies in order to guarantee the multiple uses for this system, including water supply for human population. Although nitrogen is the limiting nutrient, an effective management program must focus on the reduction of both phosphorus and nitrogen input

Efeitos da tilápia do Nilo, Oreochromis niloticus, sobre a biomassa planctônica e a transparência da água ao longo de um gradiente de enriquecimento por nutrientes

The omnivorous filter-feeding fish, Nile tilapia (Oreochromis niloticus), can have negative effects on water quality enhancing the eutrophication process. These effects depend on the nutrient enrichment level in the water. We carried out a mesocosm experiment for five weeks in a tropical man-made lake in Brazil to test ifthe effects of tilapias depend on of the level of nutrient enrichment. The experiment lasted for 5 weeks and a factorial 2x5 experimental design was used where the presence and absence of tilapias were manipulated in combination to 5 different levels of nutrient load in a total of 10 treatments. A two way repeated measure ANOVA was performed to evaluate the effects of time (t), tilapia (F), nutrients (NP) and the interactions among these factors on: chlorophyll a, water transparency, total phosphorous, total nitrogen, N:P ratio, zooplankton biomass and phytoplankton biovolume. The tilapia effect was evident, but nutrient enrichment didn t have any effect on the variables analyzed. Tilapia decreased the water transparency, total zooplankton biomass, calanoid copepod biomass, nauplii copepod biomass and cladocerans biomass. On the other hand, tilapia had no effect on phytoplankton biovolume. This lack of effect on phytoplankton is probably due to tilapia grazing that may counteract the positive effect of tilapia on phytoplankton via trophic cascades and nutrient recycling. Hence, a reduction in tilapia stock would not be an effective way to reduce phytoplankton biomass and improve water quality

Política de formação de professores: uma leitura a partir da análise do programa especial de formação de professores para a educação básica PROEB/UFMA

Study of Teacher Education Policy: a reading from the analysis of Programa Especial de Formação de Professores para a Educação Básica Proeb - aims to analyze the initial teacher training developed by the Universidade Federal do Maranhão - UFMA. Proeb is a policy of in-service training of teachers, formulated and implemented in the context of current educational policies for basic education. This work assumes that the guidelines developed in the last decades of the twentieth century are linked to international organizations that spread in Latin America continent a homogeneous model of training which has as main features to be held in service through the mode the distance and the school as a leading locus. In Brazil, these guidelines are supported on the Law of Directives and Bases of National Education No. 9.394/96 and Report 09/2001, which deals with the Syllabus Guidelines for the formation of Basic Education Teachers. To carry out the study was taken as reference, the syllabus developed for the deployment of Proeb from 1998 to 2002, specifically the proposal operationalized in the Degree Course of Mathematics in the city of Vitória do Mearim in Maranhão. To conduct the study, it was used literature as a way to deepen understanding, clarify and aim the conceptual aspect of the object researched. The documental research was consisted in the analysis of legal documents concerning the reform of education policies, teacher training and pedagogical project Proeb/UFMA and, finally, the semi-structured interviews were used to allow a better understanding of the subjects involved with research. The data analysis has shown that the curriculum designed to operationalize the course of undergraduate mathematics Proeb/UFMA, despite having guidelines that point to the separation of theory/practice dichotomy and establish as a principle work as an educational principle, has an disciplinary curriculum organization that reinforces the instrumental view of the syllabus, not enabling in practice, the execution of their initial proposal. Concerning to the view of graduates on the course, they highlight the weaknesses of the course, but also evidence that it has allowed an improvement of initial training, through the disciplines of the common core syllabus of courses and special training. It is possible seeing in graduates words, that the course have had repercussions in their teaching and improving their integration into the labor market and in the community of Vitória do Mearim. Overall, these developments have indicated evidence of teacher professionalization, although they are incipient. The work has shown that for the professionalization of teachers is introduced, the syllabus of undergraduate teacher education must overcome the traditional view of syllabus and implement contextualized curricula in a multidisciplinary approach involving, in equal proportions, the general education and training specific course. Accordingly, it is believed in need to review the role of the University in the formative process, as well as recovering as part of educational policies, the omnilateral size of teacher education

Reconceitualização das categorias de skemp de compreensão relacional e compreensão instrumental como critérios globais

The thesis presents a systematic description about the meaning, as Skemp, relational understanding and understanding instrumental, in the context of mathematics learning, being that we had as a guide his understanding of the schema. Especially, we analyze some academic productions, in the area of Mathematics Education, who used the categories of understanding relational and instrumental understanding how evaluative instrument and we see that in most cases the analysis is punctual. Being so, whereas the inherent understanding relational schema has a network of connected ideas and non-insulated, we investigated if the global analysis, where it is the understanding of the diversity of contributory concepts for formation of the concept to be learned, is more appropriate than the punctual, where does the understanding of concepts so isolated. For this, we apply a teaching module, having as main content the Quaternos Pythagoreans using History of Mathematics and the work of Bahier (1916). With the data we obtained the teaching module to use the global analysis and the punctual analysis, using research methodology the Case Study, and consequently we conduct our inferences about the levels of understanding of the subject which has made it possible for us to investigate the ownership of global analysis at the expense of punctual analysis. On the opportunity, we prove the thesis that we espouse in the course of the study and, in addition, we highlight as a contribution of our research evidence of need for a teaching of mathematics that entices the relational understanding and that evaluation should be global, being necessary to consider the notion of schema and therefore know the schematic diagram of the concept that will be evaluated

A interpretação dos sintagmas nominais com adjetivos atributivos por alunos de inglês instrumental

This present work has as objective to analyze the interpretation of the syntactic and semantic meaning performed by third graders in the nominal groups (NGs) with attributive adjectives in the English language in a text of the final exam in the ESP (English for Specific Purposes) discipline. The corpus is made up of 30 exams of two classes from a third grade institution of the biomedical area, corresponding to the basic and advanced levels of the second term in 2006. The text has 24 NGs of different lexical content, a total of 27 NGs in the whole text summing up to 810 analyzed occurrences. The analysis is carried out at the morphologic, syntactic and semantic levels using as theoretical background the traditional and functional grammars (QUIRK et al, 1985; CELSE-MURCIA et al, 1998; TUCKER, 1998), in their semantic aspects, the Semantics (FRAWLEY, 1992) and the Cognitive Linguistics (TAYLOR, 2002). We concluded that the main difficulties were due to the lack of vocabulary and to the use of mother tongue strategies instead of using the top-down strategies for reading a text in English to compensate this gap. We also observed that even when the vocabulary was known, there were difficulties in establishing the semantic and syntactic relations between modifier and noun head. We suggested improvements for the teaching of reading English texts at the third grade grounded in the obtained results such as a more comprehensive study of the several different morphologic and syntactic structures of the NGs with premodifiers and their semantic consequences, an approach of the morphologic, syntactic and semantic aspects of the NGs and the use of both top-down and bottom-up strategies when reading a NG in the English language

Programa Agente jovem em Arez/RN: juventude e violação de direitos

This paper proposes discusses the theme of the youth and of the violation of rights in the context of the Young Agent Program developed in the local authority of Arez/RN, sugar cane region of the Brazilian northeast. We take like empirical reference, the young people in the age group from 15 to 17 years old that were participating of the activities of the Program, in the period of April to July of 2008. Objectives of this study were constituted, economical-partner apprehended the conditions and cultural of the young participants of the Young Agent Program, in the context of violations of rights; as well as the analysis of the limits and means, of the bases theoretician-politician, methodological and of the activities developed in the Program. In the persecution of the objectives we use like methodological instrumental the observation, activities in group with the focal group technique and the application of semi-structured interviews. As result, we notice that the violation of rights of the young persons inserted in the Young Agent Program of Arez sets itself up as reflex of the multiple determinations of the social question, inherent in the capitalist society, specified in the context of the poverty and of the social unequality that they acquire visibility in the hunger, in the unemployment / menial job, in the precarious dwelling, in the low schooling, for lack of leisure, in the violence between others. The approximations systematized in this healthy work relevant for the Unveiling of the reality of the Brazilian youth, specifically of Arez young people, in such a way that they come to subsidize future inquiries, are eaten by me also it promotes the discussion around the way like the Social Politics Programs they are implemented and driven in the capitalist society, in its neoliberal format, where the focusing and the selectivity is put on top to the detriment of the universal access of the democratic rights. So, the great challenge that is put for the XXI century is to cause to the voices from these which they do and this which build this country, in the continuous and tireless search of the rights realization in the struggle against the barbarism installed in the capitalist societycapitalista

Efeitos da tilápia do Nilo (Oreochromis niloticus) e do enriquecimento por nutrientes sobre a comunidade planctônica em um lago artificial no semi-árido brasileiro

The major aim of this study was to test the hypothesis that the introduction of the Nile tilapia (Oreochromis niloticus) and the enrichment with nutrients (N and P) interact synergistically to change the structure of plankton communities, increase phytoplankton biomass and decrease water transparency of a semi-arid tropical reservoir. One field experiment was performed during five weeks in twenty enclosures (8m3) to where four treatments were randomly allocated: with tilapia addition (T), with nutrients addition (NP), with tilapia and nutrients addition (T+NP) and a control treatment with no tilapia or nutrients addition (C). A two-way repeated measures ANOVA was done to test for time (t), tilapia (T) and nutrient (NP) effects and their interaction on water transparency, total phosphorus, total nitrogen, phytoplankton and zooplankton. The results show that there was no effect of nutrient addition on these variables but significant fish effects on the biomass of total zooplankton, nauplii, rotifers, cladocerans and calanoid copepods, on the biovolume of Bacillariophyta, Zygnemaphyceae and large algae (GALD ≥ 50 μm) and on Secchi depth. In addition, we found significant interaction effects between tilapia and nutrients on Secchi depth and rotifers. Overall, tilapia decreased the biomass of most zooplankton taxa and large algae (diatoms) and decreased the water transparency while nutrient enrichment increased the biomass of zooplankton (rotifers) but only in the absence of tilapia. In conclusion, the influence of fish on the reservoir plankton community and water transparency was greater than that of nutrient loading. This finding suggests that biomanipulation should be a greater priority in the restoration of eutrophic reservoirs in tropical semi-arid regions