A expressão políticas itinerantes é criada por Lindblad e Popkewitz para designar conceitos que circulam em reformas educacionais e propostas curriculares, em nível internacional, como resultado de processos de globalização. Neste artigo, além de apresentarmos alguns desses conceitos em diversos países, discutimos como, no Brasil, as Diretrizes Curriculares Nacionais dos cursos de Letras trazem reflexos dessas políticas e quais suas implicações para a formação de professores de línguas. De forma concomitante, buscar-se-á evidenciar que essas políticas itinerantes são ambivalentes e podem ser interpretadas como processos de desregulamentação e privatização de deveres decorrentes da modernidade líquida, conforme interpretação de Bauman (2001).

The expression traveling policies is coined by Lindblad and Popkewitz to refer to concepts that circulate internationally in educational reforms as a result of processes of globalization. The objective of this paper is to present some of these concepts in many different countries, analyze how, in Brazil, the National Guidelines for Language and Literature Programs are equally in agreement with these policies and what their implications for the language teacher education are. Meanwhile, it will be argued that these traveling policies are ambivalent and can be seen as processes of deregulation and privatization of tasks and duties due to times of liquid modernity.

The fish genus Astyanax is widespread throughout the Neotropical region and is one of the most species-rich genera of the Characiformes. Cytogenetic studies of Astyanax have revealed marked intra-and interspecific diversity, with the identification of various species complexes. In this report, we describe the karyotypic structure of two sympatric species of Astyanax (Astyanax sp. and Astyanax aff. fasciatus) from the Middle Contas River basin in the northeastern Brazilian state of Bahia. Both species had 2n = 48 but differed in their karyotypic formulae. Small heterochromatic blocks and multiple nucleolar organizer regions (NORs) were identified in both species. Terminal CMA3+/DAPI-signals were observed in Astyanax sp. and A. aff. fasciatus, mostly coincident with NORs. These results show that chromosomal markers can be used to identify species in this fish complex. These markers can provide useful information for evolutionary studies and investigations on the mechanisms of chromosomal diversity in Astyanax.

Tetragonisca angustula and Tetragonisca fiebrigi have recently been listed as valid species. This study aimed to cytogenetically investigate both species, emphasizing the new registry of B chromosomes in the tribe Meliponini. We analyzed colonies of T. angustula and T. fiebrigi collected at Tangará da Serra, Mato Grosso, Brazil, through conventional Giemsa staining, C-banding, and base-specific fluorochrome staining (CMA3/DAPI). T. angustula showed 2n = 34 chromosomes in females and n = 17 in males, with karyotype formula 2K = 34A M. T. fiebrigi showed numeric variation, with chromosome number varying from 2n = 34 to 2n = 36 in females and from n = 17 to n=18in males, with karyotype formula 2K = 32A M+2A Mc and 2K = 32A M+2A Mc + 1 or 2 B-chromosomes. The B chromosomes are heterochromatic. In T. fiebrigi, the CMA3/DAPI staining revealed four chromosomes with a CMA3 positive band. All individuals from the same colony showed the same number of B chromosomes. T. angustula and T. fiebrigi showed karyotype divergence, principally due to the presence of B chromosomes, which are found only in T. fiebrigi. Our data corroborate the status of valid species for both T. angustula and T. fiebrigi, as recently proposed.

The cytogenetic analysis of Frieseomelitta dispar and F. francoi revealed the chromosome numbers 2n = 30 and n = 15 and a karyotypic formula 2K = 4M+2Mt+4A+20A M. The number of chromosomes observed was consistent with those reported for other Frieseomelitta species. The occurrence of the Mt chromosome and other features of the karyotype formulae suggest a close relationship between F. dispar, F. francoi and F. varia. Nevertheless, it was possible to differentiate the karyotypes of the species by DAPI/CMA3 staining, which revealed GC-rich regions on two chromosome pairs of F. dispar: one acrocentric and one pseudoacrocentric. In F. francoi, the same kinds of regions were observed on a pair of metacentrics and on a pair of acrocentrics. Our analysis also confirmed the chromosome number conservation in Frieseomelitta and suggests that infrequent pericentric inversion could constitute a synapomorphy for the group including F. dispar, F. francoi, and F. varia.

Este trabalho descreve a análise, o projeto e a implementação de um reator eletrônico para lâmpadas de vapor metálico (MH) baseado em microcontrolador. O circuito do reator se fundamenta na integração de um conversor buck com um conversor flyback. A tarefa de correção do fator de potência é realizada pela etapa buck, enquanto a etapa flyback controla a potência na lâmpada fornecendo uma corrente em onda quadrada de baixa freqüência. Este é um método adequado para se evitar o fenômeno da ressonância acústica, comum em lâmpadas de descarga de alta pressão (HID). Os dois estágios conversores operam no modo de condução descontínua (DCM), o que permite o uso de apenas um interruptor de alta freqüência simplificando o controle. O reator eletrônico é controlado digitalmente e emprega um microcontrolador de baixo custo PIC16F684. Este componente é programado para desempenhar todas as tarefas necessárias aos processos de ignição, aquecimento e regime permanente da lâmpada, respondendo também pelo controle em malha fechada da corrente na lâmpada e proteções convencionais. O artigo inclui resultados experimentais obtidos de um protótipo que alimenta uma lâmpada MH de 35W.

The analysis, design and implementation of a microcontroller-based electronic ballast to supply metal halide (MH) lamps are presented. The proposed power scheme is based on the integration of the buck and flyback converters. The former providing power factor correction and the latter controlling lamp power by supplying the lamp with a low frequency square waveform current, which is a convenient way to avoid acoustic resonances in high intensity discharge (HID) lamps. Both converters operate in discontinuous conduction mode (DCM), thus allowing the use of only one high-frequency switch and simplifying the control. The electronic ballast is digitally controlled by using a low cost microcontroller PIC16F684. The microcontroller performs all the necessary tasks during starting, warming-up and steady state, including closed loop control of lamp current and protections. Experimental results for a 35W MH lamp are presented.

Cytogenetic analyses of the stingless bee Partamona helleri collected in the state of Bahia, Northeast Brazil revealed the chromosome numbers n = 18 in the haploid males and 2n = 35 in the diploid females. All karyotypes displayed one large acrocentric B chromosome, which differs from the minute B chromosomes previously described in the populations from southeastern Brazil. Giemsa staining, C-banding and DAPI/CMA3 fluorochrome staining also revealed a remarkable interpopulational divergence regarding both the regular karyotype and the B chromosomes. The B chromosomes found in the samples from Jequié, Bahia, were entirely heterochromatic, while those found in Cravolândia, Bahia, displayed a euchromatic portion at the telomeric end of the long arm. CMA3 labeling sites varied from seven to eight between the two localities in Bahia, due to the presence of an extra GC-rich block in the karyotype of the samples from Jequié. This is the first report of a large B chromosome in P. helleri and reveals the occurrence of a geographic differentiation within this species.

Although many species of the genus Trigona have been taxonomically described, cytogenetic studies of these species are still rare. The aim of the present study was to obtain cytogenetic data by conventional staining, C banding and fluorochrome staining for the karyotype characterization of the species Trigona fulviventris. Cytogenetic analysis revealed that this species possesses a diploid chromosome number of 2n = 32, different from most other species of this genus studied so far. This variation was probably due to the centric fusion in a higher numbered ancestral karyotype, this fusion producing the large metacentric chromosome pair and the lower chromosome number observed in Trigona fulviventris. Heterochromatin was detected in the pericentromeric region of the first chromosome pair and in one of the arms of the remaining pairs. Base-specific fluorochrome staining with 4'-6-diamidino-2-phenylindole (DAPI) showed that the heterochromatin was rich in AT base pairs (DAPI+) except for pair 13, which was chromomycin A3 (CMA3) positive indicating an excess of GC base pairs. Our data also suggests that there was variation in heterochromatin base composition.

Os objetivos do experimento foram determinar os efeitos de cinco níveis de concentrados na dieta sobre a eficiência de síntese microbiana, as concentrações de amônia e os valores de pH ruminal, o balanço de compostos nitrogenados e a taxa de passagem da digesta pelo rúmen de novilhos F1 Limousin x Nelore. Utilizaram-se cinco animais fistulados no rúmen, abomaso e íleo, com peso médio de 279 kg, distribuídos em quadrado latino 5 x 5, alimentados à vontade com feno de capim-coastcross e porcentagens de 25,0; 37,5; 50,0; 62,5; e 75,0% de concentrado. Amostras de líquido de rúmen para determinação de amônia e pH foram obtidas antes e 2, 4, 6 e 8 horas após o arraçoamento dos animais. As bases purinas foram o indicador microbiano utilizado e as bactérias do rúmen foram isoladas por centrifugação diferencial. A taxa de passagem foi obtida com infusão de dose única de 20 g de óxido crômico e os tempos avaliados foram imediatamente antes da infusão do indicador e 3, 6, 9, 12, 24, 36 e 48 horas após. O fluxo de nitrogênio bacteriano (Nbact) no abomaso e a eficiência microbiana em relação aos carboidratos degradados no rúmen (CHODR) não foram influenciados pelos níveis de concentrado, observando-se valores médios de 85,69 g Nbact/dia, 41,09 g Nbact/kgCHODR e 472,44 g MSbact/kgCHODR. As concentrações máximas de amônia de 17,56 mg/100mL de fluido ruminal ocorreram 2,77 horas após a alimentação. O pH do rúmen diminuiu linearmente com os níveis de concentrados e foi influenciado de forma quadrática pelo tempo de coleta. Foram observadas taxas de passagem da digesta ruminal de 0,059; 0,053; 0,073; 0,068; e 0,041.h-1, para os respectivos níveis de 25,0; 37,5; 50,0; 62,5; e 75,0% de concentrado. O aumento do concentrado na dieta não alterou o crescimento microbiano no rúmen.

The objectives of this work were to evaluate the effects of five dietary concentrate levels (25,0; 37,5; 50,0; 62,5 and 75,0%) on the efficiency of microbial synthesis, the ruminal ammonia concentrations and pH, nitrogenous compounds balance, and the digest passage rate. Five rumen, abomasum and ileum fistulated F1 Limousin x Nellore bulls, with an average initial body weight of 279 kg, were used in a 5 x 5 Latin square design. Ruminal liquid samples were obtained before and 2; 4; 6 and 8 hours after feeding to determine the ammonia and pH of the rumen. The bases purines were used as microbial indicator, and ruminal bacteria were isolated by differential centrifugation. The passage rate was obtained by infusion of an unique chromium oxide dose of 20 g and the times were evaluated before and 3; 6; 9; 12; 24; 36 and 48 hours after the indicator infusion. The abomasum Nbact flow and the microbial efficiency in relation to the degradable carbohydrates in the rumen (CHODR) were not influenced by the dietary concentrate levels, with average values of 85,69 g Nbact/day, 41,09 g Nbact/kgCHODR and 472,44 g DMbact/kgCHODR. The maximum ammonia concentration of 17,56 mg/100mL of ruminal fluid was observed 2,77 hours after feeding. Ruminal pH linearly decreased as the concentrate level increased and was in a quadratic way influenced by the collection time. Ruminal digesta passage rate of 0,059; 0,053; 0,073; 0,068 and 0,041.h-1, for the respective levels of 25,0; 37,5; 50,0; 62,5 and 75,0% of concentrate levels were observed. The increasing dietary concentrate did not change the microbial growth in the rumen.

O objetivo deste trabalho foi avaliar os efeitos de cinco níveis de concentrados (25,0; 37,5; 50,0; 62,5; e 75,0%) sobre os consumos e as digestibilidades aparentes totais e parciais da matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), do extrato etéreo (EE), dos carboidratos totais (CHO) e da fibra em detergente neutro (FDN). Cinco novilhos F1 Limousin x Nelore, não-castrados, com peso médio inicial de 279 kg, fistulados no rúmen, abomaso e íleo, foram usados em um delineamento quadrado latino 5 x 5, com cinco tratamentos, cinco períodos experimentais e cinco animais. Cada período teve duração de 14 dias - 10 dias para adaptação dos animais à ração e quatro dias para coleta de fezes e de digestas de abomaso e íleo. Utilizou-se o óxido crômico em duas doses de 10 g/dia, como indicador, para medir os fluxos de nutrientes no trato digestivo. Os consumos de EE e NDT aumentaram e o de FDN diminuiu linearmente com o incremento dos níveis de concentrados das rações. O aumento de níveis de concentrado na MS da ração resultou em acréscimos lineares nas digestilidades totais de MS, MO, PB, EE e CHO. A digestibilidade aparente total de FDN e as digestões aparentes ruminais de MS, MO, PB, CHO e FDN não foram influenciadas pelos níveis de concentrado nas rações, observando-se médias de 45,91; 54,45; 64,67; -9,92; 79,29; e 95,90%, respectivamente. Conclui-se que o aumento dos níveis de concentrado nas rações não alterou os locais de digestão dos nutrientes.

The objective of this work was to evaluate the effects of five dietary concentrate levels (25.0, 37.5, 50.0, 62.5, and 75.0%) on intake and the total and partial apparent digestibilities of dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), total carbohydrates (CHO) and neutral detergent fiber (NDF). Five rumen, abomasum and ileum fistulated F1 Limousin x Nellore bulls, with average initial weight of 279 kg were used, in a 5 x 5 Latin square design, with five treatments, five experimental periods and five animals. Each experimental period lasted 14 days - 10 days for animals adaptation to the diet and four days for feces, and abomasum and ileum digesta collection. Chromium oxide was used as indicator, in two doses of 10 g/day, to measure nutrient flows in the digestive tract. The ether extract and TDN intakes increased and of the NDF linearly decreased with the increase of dietary concentrate levels. The increment of concentrate levels in DM linearly increased the apparent total digestibilities of the DM, OM, CP, and CHO. The apparent total NDF digestibility and the apparent ruminal digestibilities of DM, OM, CP, CHO and FDN were not influenced by the dietary concentrate levels, with means of 45.91, 54.45, 64.67, -9.92, 79.29, and 95.90%, respectively. The increase of dietary concentrate levels did not affect the local of nutrients digestion.

O trabalho foi realizado para avaliar a determinação da produção de proteína microbiana com a utilização da excreção urinária de derivados de purinas; comparar a produção de proteína microbiana por intermédio dos métodos das bases purinas e da excreção urinária de derivados de purinas; determinar a produção de proteína microbiana em função do consumo de matéria seca e da porcentagem de fibra em detergente neutro da ração; e estabelecer a proporção de alantoína e ácido úrico, em relação à xantina e hipoxantina na urina. Foram realizados cinco experimentos com animais fistulados no rúmen, abomaso e íleo para estudos simultâneos de consumo, digestões totais e parciais de nutrientes e eficiência de síntese de proteína microbiana. Utilizou-se o delineamento experimental em quadrado latino 5x5, à exceção do experimento IV (4x4). Os dados foram agrupados em todos os experimentos, os que envolveram animais mestiços (I, II e III) e zebuínos (IV e V). Utilizou-se, para todos os dados agrupados, o delineamento inteiramente casualizado, em função dos níveis de concentrado da dieta. Da urina total coletada em 24 horas, foram analisados os derivados de purinas (alantoína, ácido úrico, xantina e hipoxantina) para determinar a produção microbiana. Para todos os experimentos agrupados, as excreções de derivados de purinas urinários, representadas pela alantoína e pelas purinas totais, apresentaram comportamento quadrático em função dos níveis de concentrado da ração, acompanhando o comportamento do fluxo de compostos nitrogenados microbianos (N mic) estimado pelos derivados de purinas na urina, usando a relação N purina:N total de 0,116, e o estimado pelas bases purinas no abomaso, encontrando-se valores máximos de 72,07 e 86,08 g N mic/dia, para níveis de 62,91 e 63,60% de concentrado, respectivamente. A relação alantoína e ácido úrico:purinas totais foi de, aproximadamente, 98%, indicando que a concentração de xantina e hipoxantina seria, em torno, de 2%.

The work was carried out to evaluate the microbial protein production determination by means of the urinary excretion of purine derivatives; to compare the microbial protein production by means of purine base methods and of the urinary excretion of purine derivatives; to determine the microbial protein production on the dry matter intake and percentage of neutral detergent fiber in the diet; and to establish the allantoin: uric acid ratio, in relation to the xanthine and hypoxanthine in the urine. Five experiments were carried out with steers fistulated in the rumen, abomasum and ileum, for simultaneous studies of intake, total and partial nutrient digestion and efficiency of microbial protein synthesis. An experimental 5 x 5 Latin square design, except for the experiment IV (4 x 4), was used. Data were grouped in all the experiments, the ones that involved crossbred animals (I, II and III) and Zebu animals (IV and V). For all grouped data, a completely randomized design was used in function of the dietary concentrate levels. From the total urine collected in 24 hours, the purine derivatives (allantoin, uric acid, xanthine and hypoxanthine) were analyzed to determine the microbial production. For all experiments urinary purine derivatives excretions, represented by the allantoin and the total purine, presented quadratic behavior on the dietary concentrate levels, according to the N mic flow behavior estimated by the urinary purine derivatives excretions, using purine N: total purine ratio of .116 and the estimated by the purine bases in the abomasum, reaching maximum values of 72.07 and 86.08 N mic/day for concentrate levels of 62.91and 63.60%, respectively. Allantoin: uric acid ratio was nearly to 98%, indicating that the xanthine and hypoxanthine concentration would be around 2%.