Interação silício e alumínio em plantas de arroz de terras altas cultivadas em solo alumínico

Solos com altos teores de Al tóxico podem causar diversos danos às plantas e, como consequência, diminuir sua produtividade; assim, seu manejo torna-se imprescindível para obter maiores produtividades, e o Si pode ser alternativa para diminuir a toxidez por Al em plantas. O objetivo deste trabalho foi avaliar a interação entre Si e Al em plantas de arroz de terras altas cultivadas em solo naturalmente alumínico de textura média arenosa. O delineamento experimental utilizado foi o de blocos inteiramente casualizados, dispostos em esquema fatorial 2 x 5 com quatro repetições. Os tratamentos empregados foram dois cultivares de arroz de terras altas: BRS Talento (não tolerante ao Al, moderno) e Guarani (tolerante ao Al3+, tradicional), além de cinco doses de Si (0, 30, 60, 90 e 120 mg dm-3) adicionadas ao solo. O Si fornecido ao solo contribuiu amenizando a toxidez por Al em ambos os cultivares, porém só houve acréscimo em produtividade no cultivar BRS Talento. Houve correlação positiva para produtividade de grãos do cultivar BRS Talento e teor de Si nas folhas; já o teor de Al nas folhas correlacionou-se com a produtividade de forma negativa; e também houve correlação negativa entre os teores de Si e Al nas folhas, indicando que há interação entre Si e Al em plantas de arroz.

Interação em sala de aula de língua inglesa: o feedback como estratégia do desempenho assistido

This dissertation aims at characterizing the practices as well as the effects of a teacher s feedback in oral conversation interaction with students in an English Language classroom at a Primary School, 6th Grade in Açu/RN, Brazil. Therefore, this study is based on Vygotsky s (1975) and Bruner´s (1976) researches, which state that the learning process is constructed through interaction between a more experienced individual (teacher, parents and friends) and a learner who plays an active role, a re-constructor of knowledge. It is also based on Ur´s (2006) and Brookhart s (2008) studies (among other authors in Applied Linguistic) who defend that the feedback process needs to be evaluative and formative since it sets interfaces with both students autonomy and learning improvement. Our study is based on qualitative, quantitative and interpretive researches, whose natural environment (the classroom) is a direct source of data generated in this research through field observations/note-taking as well as through the transcriptions of five English classes audio taped. This study shows the following results: the teacher still seems to accept the patterns of interaction in the classroom that correspond to the IRE process (Initiation, Response, Evaluation) in behaviorist patterns: (1) he speaks and determines the turns of speech; (2) the teacher asks more questions and directs the activities most of the time; (3) the teacher´s feedback presents the following types: questioning, modeling, repeated response, praise, depreciation, positive/negative and sarcasm feedback, whose functions are to assess students' performance based on the rightness and wrongness of their responses. Thus, this implies to state that the feedback does not seem to help students improvement in terms of acquiring knowledge because of its normative effects/roles. Therefore, it is the teacher´s role to give evaluative and formative feedback to a student so that he/she should advance in the learning of the language and in the construction of knowledge

A organização da interação professor-aluno em sala de aula: turnos e o par pergunta-resposta

Este trabalho tem como foco principal a interação em sala de aula, especificando aspectos da organização linguístico-discursiva, na produção conjunta da fala da professora e dos alunos, materializada em turnos, ressaltando o par pergunta-resposta na aula de Língua Portuguesa. Para alcançarmos esse objetivo, inspiramo-nos em alguns trabalhos acerca da organização da interação que adotaram a perspectiva dos estudos interacionais e a abordagem etnográfica, a fim de explicitar o conhecimento nos espaços de ensino e aprendizagem. Entre eles, citamos as pesquisas de Galvão (1996, 2004) e de Matêncio (2001). Nessa direção, descrevemos o processo de interação em sala de aula em uma escola pública, analisando e interpretando as ações de linguagem realizadas pela professora e pelos alunos. Teoricamente, embasamo-nos, principalmente, na Análise da Conversação, ancorando-nos no estudo pioneiro de Sacks, Schegloff e Jefferson ([1974] 2003); nos postulados de Marcuschi ([1986] 2007a); nas pesquisas de Kerbrat-Orecchioni (2006), dentre outros. Explicitamos uma tipologia de perguntas e respostas em sala de aula, quanto à sua forma e função, conforme os postulados teóricos de Stubbs (1987), Araújo (2003), Fávero, Andrade e Aquino (2006), Silva (2006) e Koshik (2010). Analisamos a organização da tomada de turno, seguida de uma investigação sobre perguntas e respostas no discurso desenvolvido face a face. Na tentativa de compreendermos o cotidiano dos envolvidos no cenário de sala de aula, adotamos a abordagem etnográfica e o método indutivo, nas perspectivas de André (2010) e Chizzotti (2006). Os dados foram gerados através de pesquisa de campo, por meio de gravações (em áudio) de aulas de Língua Portuguesa, posteriormente transcritas e transformadas no corpus de pesquisa. As análises demonstraram que a interação entre professora e alunos organizou-se em trocas de turnos, na maioria das vezes, controladas pela professora, evidenciando-se uma relação de assimetria entre os participantes. Esses turnos concretizados, geralmente, no par adjacente pergunta-resposta revelaram como a construção do conhecimento se realiza em sala de aula. Por fim, observamos que a interação em sala de aula de Língua Portuguesa é organizada por aspectos sociais e pedagógicos intrinsecamente imbricados

Procedimentos de abertura e fechamento de tópicos na interação em sala de aula

This study is part of interactional perspective, focusing on Conversation Analysis theories, from the Textual Interactive Perspective and Text Linguistics . This research, from its guiding questions, aims at understanding the interaction between teacher and students in the process of the knowledge construction as well as at describing, analyzing and understanding aspects of topical organization speech in the classroom in elementary school, observing the opening and closing procedures of the speech topics in that particular space. Considering that the procedures for opening and closing of discursive topics occur through language marks, we tried to identify which speech marks are used in the opening and closing of the topics studied in the classroom, in interaction during the collaborative process of the discourse established between teacher and students. Therefore, this study is based on authors who analyze specific questions of the text in real context of language use: Koch (1993, 1999), Jubran et al (1991), Jubran (2006), Pine (2005), Penhavel (2010), Galembeck (2012), Barros (1991), Marcuschi (1986 , 1990, 1991 , 1998 , 1999, 2003 , 2004a), Kerbrat - Orecchioni (2006), Favero (1999, 2002) and Galvão (2004, 2010). As a methodology of investigation, the study is focused on the postulates of ethnographic research in order to carry out data collection, through audio and video recordings which were transcribed, according to the NURC project proposal, with some adaptations. Data analysis showed that the procedures for opening and closing of the speech topics occurred by the use of discourse markers, in particular the marker "then", allowing us to understand that these elements are important in the topical organization speech, contributing to ensure textual cohesion and coherence. We conclude that the organization of the discursive topic in the classroom occurs through events that support the explicitness of the content of teaching and learning, considering the diverse necessity of an institutional academic plan, whose main objective is the construction of knowledge

Interação no rádio: a participação do ouvinte no programa debates do povo

The radio is just not seen as conveying information, but a media able to establish ways that generate certain direction. We see an inclusion of the listener in the construction of programs, is exposing their life stories, commenting on facts, answering questions, choosing subjects and participating in some form of radio programming. This insertion of the listener in radio programs is generally thought of as a constituent element of the message. This study aims to analyze the participation of the listener and the forms of interaction in the " Debates of the People" that thirty- past two years is the schedule for CBN Fortaleza. The investigation was conducted through observation in studio, interview, transcription, content analysis and association analysis. This is a qualitative and quantitative research while. We found that the listeners of the program had no acceptance of interactive tools such as the Internet and social networks to make their holdings. In clipping analyzed, we noted that the participation of the listener was selected according to their relationship and proximity to the topic discussed. Also detected that the opinion is superior to the listener questions on the topic. The presenter has the function to put the questions in the listener program. Among the public comments are questions and opinions on the subject and speaks of the debaters. Among the authors, use Barbosa (2009 ), Ferraretto (2007 ), Lopez (2010 ), Ortriwano (2001 ), Peruzzo (2004 ), Prata (2009 ), Primo (2006 ), Thompson (2009 ), among others

Um estudo sobre a interação estrela-planeta a partir da relação massa-período planetário com a atividade estelar

n this work, we analyze the behavior of the chromospheric and coronal activities as a function of the mass and the orbital period of extrasolar planets which were detected by transit technique. So we look for possible effects of the planet on the star s chromosphere and corona. For this study we selected a sample of 48 stars with chromospheric activity indicator and 23 with coronal activity indicator. Our work is based on the work from Pont et al. (2011) in order to study stars with planets which were obtained by transit technique. Furthermore, we studied the relationship between planetary mass and orbital period with the chromospheric and coronal activity in order to better understand which influences the planets cause in the outer layers of stellar atmosphere. In our analysis we can observe that the mass of the planets exerts no influence in the stellar activity. However, we observed that the stellar coronal and chromospheric activities decrease with the increase of the orbital period of the planet

Um estudo sobre a interação estrela-planeta a partirda relação massa-período planetário com a atividade estelar

In this work, we analyze the behavior of the chromospheric and coronal activities as a function of the mass and the orbital period of extrasolar planets which were detected by transit technique. So we look for possible effects of the planet on the star s chromosphere and corona. For this study we selected a sample of 48 stars with chromospheric activity indicator and 23 with coronal activity indicator. Our work is based on the work from Pont et al. (2011) in order to study stars with planets which were obtained by transit technique. Furthermore, we studied the relationship between planetary mass and orbital period with the chromospheric and coronal activity in order to better understand which influences the planets cause in the outer layers of stellar atmosphere. In our analysis we can observe that the mass of the planets exerts no influence in the stellar activity. However, we observed that the stellar coronal and chromospheric activities decrease with the increase of the orbital period of the planet

Interação estrela planeta: sobre o magnetismo de planetas gigantes gasosos

In this thesis we analyze the effects that the presence of a near gas giant planet can cause in its host star. It has been argued that the star planet interaction can cause changes in the coronal and chromospheric stellar activity. With this in mind, we analyze a sample of 53 extrasolar planets orbiting F, G and K main sequence stars, among them three super-Earths. In this analysis, we look for evidence of changes in the chromospheric activity due to the proximity of the giant planet. We show that, so far, there is not enough evidence to support such a hypothesis. Making use of the same sample and also taking in account available data for the Solar System, we revisit the so-called magnetic Bode s law. This law proposes the existence of a direct relationship between magnetism and rotation. By using estimations for the stellar and planetary magnetic momentM and the angular momentumL, we construct a Blackett s diagram (logL 􀀀logM). In this diagram is evident that the magnetic Bode s law is valid for both the Solar System and the new planetary systems

Efeitos da interação dipolar na nucleação de vórtices em nano-cilindros magnéticos

The effect of confinement on the magnetic structure of vortices of dipolar coupled ferromagnetic nanoelements is an issue of current interest, not only for academic reasons, but also for the potential impact in a number of promising applications. Most applications, such as nano-oscillators for wireless data transmission, benefit from the possibility of tailoring the vortex core magnetic pattern. We report a theoretical study of vortex nucleation in pairs of coaxial iron and Permalloy cylinders, with diameters ranging from 21nm to 150nm, and 12nm and 21nm thicknesses, separated by a non-magnetic layer. 12nm thick iron and Permalloy isolated (single) cylinders do not hold a vortex, and 21nm isolated cylinders hold a vortex. Our results indicate that one may tailor the magnetic structure of the vortices, and the relative chirality, by selecting the thickness of the non-magnetic spacer and the values of the cylinders diameters and thicknesses. Also, the dipolar interaction may induce vortex formation in pairs of 12nm thick nanocylinders and inhibit the formation of vortices in pairs of 21nm thick nanocylinders. These new phases are formed according to the value of the distance between the cylinderes. Furthermore, we show that the preparation route may control relative chirality and polarity of the vortex pair. For instance: by saturating a pair of Fe 81nm diameter, 21nm thickness cylinders, along the crystalline anisotropy direction, a pair of 36nm core diameter vortices, with same chirality and polarity is prepared. By saturating along the perpendicular direction, one prepares a 30nm diameter core vortex pair, with opposite chirality and opposite polarity. We also present a theoretical discussion of the impact of vortices on the thermal hysteresis of a pair of interface biased elliptical iron nanoelements, separated by an ultrathin nonmagnetic insulating layer. We have found that iron nanoelements exchange coupled to a noncompensated NiO substrate, display thermal hysteresis at room temperature, well below the iron Curie temperature. The thermal hysteresis consists in different sequences of magnetic states in the heating and cooling branches of a thermal loop, and originates in the thermal reduction of the interface field, and on the rearrangements of the magnetic structure at high temperatures, 5 produce by the strong dipolar coupling. The width of the thermal hysteresis varies from 500 K to 100 K for lateral dimensions of 125 nm x 65 nm and 145 nm x 65 nm. We focus on the thermal effects on two particular states: the antiparallel state, which has, at low temperatures, the interface biased nanoelement with the magnetization aligned with the interface field and the second nanoelement aligned opposite to the interface field; and in the parallel state, which has both nanoelements with the magnetization aligned with the interface field at low temperatures. We show that the dipolar interaction leads to enhanced thermal stability of the antiparallel state, and reduces the thermal stability of the parallel state. These states are the key phases in the application of pairs of ferromagnetic nanoelements, separated by a thin insulating layer, for tunneling magnetic memory cells. We have found that for a pair of 125nm x 65nm nanoelements, separated by 1.1nm, and low temperature interface field strength of 5.88kOe, the low temperature state (T = 100K) consists of a pair of nearly parallel buckle-states. This low temperature phase is kept with minor changes up to T= 249 K when the magnetization is reduced to 50% of the low temperature value due to nucleation of a vortex centered around the middle of the free surface nanoelement. By further increasing the temperature, there is another small change in the magnetization due to vortex motion. Apart from minor changes in the vortex position, the high temperature vortex state remains stable, in the cooling branch, down to low temperatures. We note that wide loop thermal hysteresis may pose limits on the design of tunneling magnetic memory cells

Demonstração didática da interação entre correntes elétricas

Apresentamos a primeira experiência crucial de Ampère mostrando a interação entre dois fios metálicos conduzindo correntes elétricas. Discutimos sua importância na história da física. Descrevemos uma reprodução moderna dos procedimentos e observações de Ampère com materiais de baixo custo.

Interação entre professora e alunos em salas de aula com proposta pedagógica de educação inclusiva

Correntes teóricas presentes na literatura científica têm demonstrado a importância das relações interpessoais para o processo de construção do conhecimento. É no contexto da interação professor e aluno que se configura a relação entre as necessidades educacionais dos alunos e as respostas pedagógicas a elas disponibilizadas, o que envolve o domínio do conhecimento pelo professor, sua capacitação técnico-científica, a competência de ensinar pesquisando, as características sócio-culturais e o perfil psicológico dos atores sociais envolvidos- professor e aluno. Buscando melhor compreender este universo, elaborou-se este estudo que teve como objetivo descrever as interações ocorridas entre uma professora, e seus alunos, em classes em que se propunha adotar uma prática pedagógica inclusiva. Os dados foram coletados em 2 salas de aula, em escola estadual de Ensino Fundamental, no município de Bauru. O processo de coleta de dados se deu através do registro da realidade de sala de aula em vídeo tape. Optou-se por este método, por permitir a recuperação posterior dos dados. A coleta se deu no transcorrer do 1º semestre do ano letivo de 2001. A análise fundamentou-se em sistema prévio de categorias, e tratou os dados quantitativa e qualitativamente. Os resultados demonstraram peculiaridades e diferenças nas interações da professora com os seus alunos, em função da presença ou ausência da deficiência. Indicaram, também, que a interação vem demonstrando avanços na prática educacional, no que diz respeito à atenção pedagógica, da professora, ao aluno com deficiência.

Caracterização comportamental e distribuição de neurônios inibitórios em um modelo animal de autismo induzido por ácido valpróico

Autism comprises a heterogeneous group of neurodevelopmental disorders that affects the brain maturation and produces sensorial, motor, language and social interaction deficits in early childhood. Several studies have shown a major involvement of genetic factors leading to a predisposition to autism, which are possibly affected by environmental modulators during embryonic and post-natal life. Recent studies in animal models indicate that alterations in epigenetic control during development can generate neuronal maturation disturbances and produce a hyper-excitable circuit, resulting in typical symptoms of autism. In the animal model of autism induced by valproic acid (VPA) during rat pregnancy, behavioral, electrophysiological and cellular alterations have been reported which can also be observed in patients with autism. However, only a few studies have correlated behavioral alterations with the supposed neuronal hyper-excitability in this model. The aim of this project was to generate an animal model of autism by pre-natal exposure to VPA and evaluate the early post-natal development and pre-puberal (PND30) behavior in the offspring. Furthermore, we quantified the parvalbumin-positive neuronal distribution in the medial prefrontal cortex and Purkinje cells in the cerebellum of VPA animals. Our results show that VPA treatment induced developmental alterations, which were observed in behavioral changes as compared to vehicle-treated controls. VPA animals showed clear behavioral abnormalities such as hyperlocomotion, prolonged stereotipies and reduced social interaction with an unfamiliar mate. Cellular quantification revealed a decrease in the number of parvalbumin-positive interneurons in the anterior cingulate cortex and in the prelimbic cortex of the mPFC, suggesting an excitatory/inhibitory unbalance in this animal model of autism. Moreover, we also observed that the neuronal reduction occurred mainly in the cortical layers II/III and V/VI. We did not detect any change in the density of Purkinje neurons in the Crus I region of the cerebellar cortex. Together, our results strengthens the face validity of the VPA model in rats and shed light on specific changes in the inhibitory circuitry of the prefrontal cortex in this autism model. Further studies should address the challenges to clarify particular electrophysiological correlates of the cellular alterations in order to better understand the behavioral dysfunctions

Resposta celular Th1 /Th2 na doença periodontal experimental, em ratos: um estudo imuno-histoquímico

Host response plays a major role in the pathogenesis of periodontal disease. Mediators such as inflammatory cytokines which are secreted during the immune response to bacterial challenges have ambiguous functions that may or may not lead to protection of the attacked tissue. In this context, experimental evidence suggests that T-helper 1 (Th-1) and T-helper 2 (Th-2) mediated responses are potentially important during the disease process. The aims of this study therefore were to further clarify the role played by Th2 cells during different time points of the active phase of periodontal disease, as well as, to investigate whether there was any evidence of a Th1 response in the periodontal disease microenvironment. Experimental periodontitis was induced in 30 Wistar male rats by placing cotton ligatures around the mandibular first molars. The rats were then randomly divided into two groups. Group1 (G1=15) and Group 2 (G2=15). In G1 the ligatures were maintained for 2 days, whereas in G2 the ligatures were left for 15 days, a time point that corresponds to the advanced stage of periodontal disease The contra-lateral teeth served as controls (no ligatures). Immunohistochemical investigation for the presence in gingival tissue of Th2 specific transcription factor (GATA3) and the subunit of the IFN-γ receptor was carried out after the disease induction period. Light microscopy analysis revealed a decrease in the expression of GATA-3 as bone loss progressed. On the other hand, although IFN-γ R1 was detected at an early stage of the active phase of disease its expression remained unaltered during the remaining period of the study. These results indicate that the Th2 response have a protective role during the pathogenesis of periodontal disease and that the progression of the periodontal disease is related with the unbalance of the responses Th1/Th2

Expressão imuno-histoquímica das integrinas α2ß1, α3ß1, e α5ß1, em mucosa oral normal, hiperplasia fibroepitelial inflamatória oral e displasia epitelial oral

The objective of this study was perform by the streptoavidin-biotin technique an immunohistochemical analysis of α2β1, α3β1e α5β1 integrins in 11 normal oral mucosa (NOM), 16 oral inflammatory fibroepithelial hyperplasia (OIFH) and 25 oral epithelial dysplasia (OED) (16 mild, 2 moderates and 7 severe), to determine if exists qualitative alteration in the expression of these integrins and if this guard relation with the oral epithelial modifications. It was observed that for the α2β1 integrin the majority of the sample showed a predominantly intense labeling diffusely distributed in the intercellular contacts and the cytoplasm of cells of the basal and suprabasal layers, without difference of this profile between the different types of specimens, however with a trend to weak or loss of expression in 21.1% of the OEDs, being all the specimens that had not expressed this heterodimer, severe OEDs. For the α3β1 integrin the majority of the sample showed a weak or absent labeling in basal layer. The α5β1 integrin showed a predominant strong diffuse labeling in the intercellular contacts and cytoplasm in the suprabasal layer, with difference only in the labeling intensity between the types of specimens, inhabiting this difference in the OEDs, where 12 (48%) specimens had shown a weak labeling. It was concluded that the evaluated integrins can be involved in the cell-cell, cell-ECM interactions modulating the cellular differentiation and maintenance of the epithelial structural arrangement. The variable expression of the α5β1 integrin in the OEDs, could suggest, respectively, a role of this molecule in the cellular survival, with intention to perpetuate the modified phenotype in these lesions, or a suppressor role on the modified phenotype due to lack of interaction of this molecule with the fibronectina of the MEC

Estudo da detecção do DNA do papiloma vírus humano (HPV) e da expressão imuno-histoquímica de proteína do ciclo celular no carcinoma epidermóide oral

Oral squamous cell carcinoma (OSCC) is the most common malignancy in oral cavity and human papillomavirus (HPV) may have an important role in its development. The aim of this experiment was to investigate the HPV DNA and viral types in 90 cases of OSCC. Moreover, a comparative analysis between the cases of OSSC with and without HPV DNA was performed by using cell cycle markers p21 and pRb in order to detect a possible correlation of these proteins and HPV infection. DNA was extracted from paraffin embedded tissue and amplified by PCR (polymerase chain reaction) with primers PCO3+ e PCO4+ for a fragment of human β-globin gene. After this procedure, PCR for HPV DNA detection was realized using a pair of generic primers GP5+ e GP6+. Immunohistochemical study was performed by streptoavidin-biotin technique and antibodies against p21 and pRb proteins were employed. Eighty-eight cases were positive for human β-globin gene and HPV DNA was found in 26 (29.5%) of then. It could not be detected significant correlation between HPV and age, sex and anatomical sites of the lesion. The most prevalent viral type was HPV 18 (80.8%). Regarding the immunohistochemical analysis, it was detected significant association between HPV presence and pRb immunoexpression (p=0,044), nevertheless, the same was not observed in relation to p21 protein (p =0,416). It can be concluded that the low detection of HPV DNA in OSCC by the present experiment suggests a possible role of the virus in the development and progression in just a subset of this disease