994 resultados para conteúdo celular


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Background: Embryonic stem cells are cells derived from early-stage embryos that are characterized by pluripotency and self-renewal capacity. The in vitro cultured murine embryonic stem cells can indefinitely propagate in an undifferentiated state in the presence of leukemia inhibitory factor (LIF). However, when stimulated, these cells can differentiate into cell lines derived from all three embryonic germ layers. The trichostatin A (TSA) is an epigenetic modifier agent and several studies have used the TSA to stimulate cellular differentiation. However, most of these studies only assessed one TSA concentration. Therefore, this study aimed to evaluate the effects of different TSA concentrations on histone hyperacetylation during in vitro cell differentiation of murine pluripotent embryonic stem cells, cultured with or without LIF, in the quest of to standardize their application on early cultures of embryonic stem cells.Materials, Methods & Results: Undifferentiated murine embryonic stem cells were plated in the presence of different TSA concentrations (0 nM, 15 nm, 50 nM and 100 nM) in the presence or absence of LIF. Thus, the treatments were evaluated in undifferentiated embryonic stem cells cultured in the presence of LIF (Control group: 0 nM LIF(+); Group 15 nM LIF+; Group 50 nM LIF+ and Group 100 nM LIF+), and in embryonic stem cells cultured in the absence of LIF (Control group: 0 nM LIF; Group 15 nM LIF(-); Group 50 nM LIF(-) and Group 100 nM LIF-). Treatment with TSA was performed for 24 h. After that the medium was replaced with fresh medium without TSA. Samples were collected at 0, 12, 24, 36 and 48 h after the beginning of the experiment. Three replicates were performed in each experimental group. The relative amount of Histone H3 lysine 9 acetylation was analyzed in all groups, as well as the cell proliferation in the embryonic stem cells cultured in the presence of LIF. In the control group (0 nM), the absence of LIF resulted in higher levels (P < 0.05) of H3lys9ac compared to the cultures supplemented with LIF. In the embryonic stem cells cultured in the presence of LIF, the 50 nM and 100 nM treatments resulted in higher levels (P < 0.05) of H3lys9ac when compared with 0 nM and 15 nM treatments. Evaluating the Hoechst area in the 0 nM group, it was observed that the number of cells increased (P < 0.05) according to the time of culture. Treatment with 15 nM also reflected a similar distribution, but the Hoechst area in 15 nM group was lower (P < 0.05) at 24 and 48h when compared to the observed in the control group. In the 100 nM treatment, was observed that the area of Hoechst was lower (P < 0.05) to that obtained in the control group at 12, 24 and 48h. In addition, it was observed that treatment with TSA induces greater cellular differentiation when compared to control groups in stem cells cultured in the presence of LIF as well as in the absence of LIF.Discussion: In the present study it was observed that TSA treatment increased the levels of histone acetylation in murine embryonic stem cells at a 50 nM concentration, making it possible to reduce the concentration recommended in the literature (100 nM). In addtion, it was concluded that the lower TSA concentrations utilized (15 nm and 50 nM) was less harmful to cellular proliferation than the 100 nM TSA concentration.

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Since the enactment of LDBEN 9.9394/96, Physical Education began to be understood as a curricular component in school. Thus, we see the need for systematization of content. We observed that the physical education classes at the public schools in Natal/RN from the game content, teachers did not use the existing proposals for systematization. And it was on this reality that the study occurred, aiming to present and discuss a proposal to systematization the game content in physical education classes in elementary and secondary education. Accordingly, we departed of following question: What possibilities of systematization of the game content in school physical education classes?. The methodology used was the action research, which allowed us to structure the intervention plan for the game content, directed to a reflective didactic process. The dialogue with action research provided an opportunity to understand of the proposal of systematization, the knowledge of game content, the planning and process of teaching and learning in physical education lessons developed. We use the proposed systematization the book Educação Física Escolar e Organização Curricular , to direct and organize the lesson plans. As research technique, we use the participant observation, filming, photographic records and field diary, guiding us in the debates and discussions about the field of research. The applications of the lesson plans were carried out in three schools, all located in Natal / RN: Escola Municipal Professora Ivonete Maciel, Escola Municipal Professor Ulisses de Góis e Professor Escola Estadual Josino Macedo. The members of this study were students PIBID-EF-UFRN, teachers, supervisors and school. They made the bridge between research and action, theoretical foundation and pedagogical practice, university and school. The results were advanced for beyond the propositions submitted by the above-mentioned book. For the Elementary School 1, the proposed systematization broadened experiences and learning of knowledge of the game and of playful and body manifestations. Provided an opportunity to know and learn about game of make account, rules, popular games, cooperative games, among others. For Elementary Schools 2 and Middle education, systematized lessons allowed the practical, the incorporation of knowledge of the game and its features: such as rules, origin, meaning of the name, different denominations, among others. The students experienced and learned, popular games, pre-sport games, cooperative games, with recycled material, among others. The treatment from three dimensions of contents: procedural, conceptual and attitudinal, occurred parallel to approach the game content, and in conjunction with our interventions, not being done separately during practice, but an ongoing process during class. This new perspective of work the game, in a systematized way, with applying, description and discussion the activities, allowed elaborate a summary framework of thematizations for game content, by year of teaching

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A compactação do solo tem sido fator físico limitante ao crescimento das plantas. Este trabalho objetivou avaliar a produção de soja (Glycine max cv. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) 48) em razão do conteúdo de água e da compactação do solo. Usou-se o delineamento inteiramente casualizado, em esquema fatorial 4x2, ou seja, quatro níveis de resistência à penetração (entre 0,27 e 4,32 MPa) e dois níveis de retenção de água pelo solo (0,05 e 0,01 MPa). Foram utilizadas amostras de Latossolo Vermelho textura média (LVd) e Latossolo Vermelho textura argilosa (LVef), coletadas na profundidade de 020 cm, passadas em peneira de 0,4 cm e compactadas em camadas de 3 cm, em vasos de 20 cm de altura e 25 cm de diâmetro (9,82 L). Os níveis de resistência à penetração foram determinados com o penetrômetro de anel dinamométrico. O nível crítico de resistência do solo à penetração, em relação à produção de grãos, foi de 1,66 e 2,22 MPa, no LVd, e 3,05 e 2,81 MPa, no LVef, para o conteúdo de água retida na tensão de 0,05 e 0,01 MPa, respectivamente. A maior produção de grãos foi obtida na tensão de 0,01 MPa. A produção de grãos de soja é afetada em níveis críticos de resistência do solo à penetração superiores a 2 MPa em latossolos com conteúdo de água retida na tensão de 0,01 MPa.

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This study aimed to validate the contents of an Instrument for Nursing Consultation in the Home Visit of people with Spinal Cord Injury (INCEVDOP-LM), based on the Self-Care Deficit Theory. The methodological development study was conducted with spinal cord injured (SCI) people ascribed in the Family Health Units the city of Natal/RN/Brazil, and with the nurses of these institutions. The study was conducted from Januray 2012 to January 2013 in two phases: the first aimed to identify the need for self-care of persons with SCI, and the second to develop and validate the INCEVDOP-LM. The first phase consisted of a census study of people with SCI living in Natal/RN. In the second phase, a non-probabilistic convencience sample of subjects was selected to form two groups: First stage - Group 1 of the first stage was comprised by 73 adults with SCI diagnosed with paraplegia or tetraplegia, with cognitive function preserved and that were registered to some family health unit; Group 2 of the Second phase was composed of six experts that were nurses with doctoral formation, scientific experience in the area of technology development or assistance to persons with SCI, and with publications in periodicals Qualis A2. Data collection of the first phase was conducted through home visits of people with SCI that responded three instruments: Questionnaire I (comprised of demographic and socioeconomic variables), The Competency Rating Scale for Self-care (ASA) and the Barthel Index (an instrument for evaluation of functional capacity). The research for the second phase was conducted in two stages: I-construction of the INCEVDOP LM; II-validation of the INCEVDOP-LM. The instrument and an evaluation form were forwarded to the experts for the validation. The correlations between the responses were analyzed by the Kappa test, with accepting values of>0.75. The evaluation criteria were: organization, clarity, simplicity, readability, appropriateness of vocabulary, objectivity, accuracy, reliability and suitability and the positive responses with frequency values of≥90% were considered excellent. The chi-square test was used to investigate the differences between proportions. The study attended to the principles of Human Rights CNS Resolution 196/96. Results were reported by means of four articles derived from the study. The findings indicate that the items that showed disagreement among experts (k=0.02) were diagnoses, interventions and evaluation of the nursing features pertaining to the domains of Nutrition, Hygiene, Elimination, Physical, Social and Psychological, and of the Ability to perform work activities feature. Agreement among the experts were reported for the other items, with kappa ranging from 0.72 to 1. After removing items with disagreement, all criteria achieved excellent rates and no significant differences were observed between the proportions of responses of evaluation of experts (p>0.05). We conclude that the instrument shows validity to serve as a guide for nurses to conduct a systematic consultation during the home visit to people with spinal cord injury, with emphasis on self-care. The instrument must go through other levels of validation when applied in the clinical setting

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Este estudo teve como objetivo construir e validar conteúdo de instrumentos avaliativos sobre conhecimento e habilidade de enfermagem no procedimento de sondagem nasogástrica. Trata-se de um estudo metodológico realizado na Universidade Federal do Rio Grande do Norte (UFRN) e na Universidade do Estado do Rio Grande do Norte (UERN). A amostra foi composta por 23 juízes, selecionados a partir dos critérios de inclusão: serem enfermeiros, docentes nas disciplinas de Semiologia e/ou Semiotécnica de Enfermagem, ter no mínimo um ano de experiência nestas disciplinas e ser das instituições selecionadas para o estudo. A pesquisa se desenvolveu em três etapas: (A) construção de dois instrumentos com base na revisão da literatura que resultou em um roteiro de observação da habilidade estruturado composto por 28 itens e um questionário sobre o conhecimento com 12 questões; (B) submissão dos instrumentos aos juízes, no período de junho a setembro de 2012, os quais deveriam julgar cada item como adequado , adequado com alterações ou inadequado , além de fazer uma avaliação geral de cada instrumento baseada em 10 critérios adaptados do referencial metodológico de Pasquali; e (C) validação com a verificação do nível de concordância entre os juízes, por meio da aplicação do Índice de Validade de Conteúdo (IVC) e do Índice Kappa. Utilizou-se o nível de consenso maior que 0,75 para o IVC e maior que 0,61 (bom) para o Índice Kappa. Estudo aprovado pelo Comitê de Ética em Pesquisa do Hospital Universitário Onofre Lopes (CEP/HUOL), sob CAAE nº 0002.0.294.000-10. Após serem codificados e tabulados, os dados foram analisados por meio de estatística descritiva. Dos 23 juízes, 87% eram do sexo feminino, com média de idade de 36,5 anos, 73,9% atuavam na UFRN, 78,3% possuíam mestrado acadêmico e 69,6% atuavam exclusivamente na docência. A média de tempo de experiência na docência foi de 7,9 anos e nas disciplinas de Semiologia e/ou Semiotécnica de Enfermagem foi de 5,6 anos. No julgamento do roteiro de observação estruturado e do questionário sobre o conhecimento, nenhum item/questão considerou-se inadequado, uma vez que todos obtiveram nível de concordância dentro dos índices estabelecidos (IVC > a 0,75 e Kappa > 0,61). Em relação ao roteiro estruturado para avaliar habilidade, dos 28 itens presentes, 13 apresentaram índice de concordância perfeito (IVC=1,00; Kappa= 1,00) e outros 15 foram considerados adequados com alterações, principalmente no que diz respeito à sequência instrucional dos tópicos, clareza e vocabulário. No questionário sobre o conhecimento, dentre as 12 questões que o compunham, 03 apresentaram índice de concordância perfeito e as demais adequadas com alterações quanto aos critérios vocabulário, clareza, atualização e precisão. Em relação à avaliação geral dos instrumentos, o roteiro estruturado de habilidade obteve IVC de 0,95 e Kappa de 0,91 e o questionário do conhecimento, IVC de 0,97 e Kappa de 0,94. Os dois instrumentos mostraram-se válidos quanto ao seu conteúdo, e constituem ferramentas para fomentar a qualidade da assistência de enfermagem em relação ao conhecimento e à habilidade em sondagem nasogástrica

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The competition in the telecommunications industry has grown in Brazil since the privatization, forcing companies that are active in the market to a growing commitment to quality products and services in order to survive. In this context, this work aims to understand the main factors that influence the degree of satisfaction exists in respect of a mobile operator with its corporate customers. The research covered theoretical concepts and analytical models of quality management system and models of indices related to the measurement of customer satisfaction. For the field research was carried out in a practical application of the main approaches based on this thesis by a case study in corporate segment, through a questionnaire applied to 10 consultants and 40 corporate customers of that company. Comparing the results of research with the consultants and corporate clients there is the concern of respondents to the indicators that comprise the constructs of customer satisfaction, commitment calculated, the price index and the handling of complaints, denoting the dissatisfaction of the general assessment for corporate customers with the carrier, against its current expectations. It is concluded that the mobile operator of the telecommunications industry have a big challenge, after ten years of privatization and consequently the period of rapid expansion of customer base and with the depleted, retain corporate customers as highly strategic, thus avoiding that migrate to other companies. We emphasize the need for further research and analysis of different approaches through research and using the same models to specifically evaluate and measure customer satisfaction of mobile enterprise, to adjust the model to the national market. Finally, we suggest the creation of an effective customer loyalty program with a strategy of relationship and specific to the corporate sector of mobile telephony

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This thesis deals with the factors affecting customer satisfaction and loyalty in the mobile phone telecom sector. It is adapted a model proposed by Johnson et al. (2001) of quality and loyalty antecedent factors. It is conducted a survey with a sample of 385 customers of mobile phone telecom sector in Teresina city, a capital of a Northeastern State of Brazil, and descriptives and multiple regression statistical analysis. The main findings related to satisfaction are that quality and service price are the significant factors affecting it. Regarding loyalty, satisfaction, image, affective commitment, and calculate commitment are the significant factors to explain it. The overall model used fairly explain the satisfaction and loyalty outcomes

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With the rapid growth of databases of various types (text, multimedia, etc..), There exist a need to propose methods for ordering, access and retrieve data in a simple and fast way. The images databases, in addition to these needs, require a representation of the images so that the semantic content characteristics are considered. Accordingly, several proposals such as the textual annotations based retrieval has been made. In the annotations approach, the recovery is based on the comparison between the textual description that a user can make of images and descriptions of the images stored in database. Among its drawbacks, it is noted that the textual description is very dependent on the observer, in addition to the computational effort required to describe all the images in database. Another approach is the content based image retrieval - CBIR, where each image is represented by low-level features such as: color, shape, texture, etc. In this sense, the results in the area of CBIR has been very promising. However, the representation of the images semantic by low-level features is an open problem. New algorithms for the extraction of features as well as new methods of indexing have been proposed in the literature. However, these algorithms become increasingly complex. So, doing an analysis, it is natural to ask whether there is a relationship between semantics and low-level features extracted in an image? and if there is a relationship, which descriptors better represent the semantic? which leads us to a new question: how to use descriptors to represent the content of the images?. The work presented in this thesis, proposes a method to analyze the relationship between low-level descriptors and semantics in an attempt to answer the questions before. Still, it was observed that there are three possibilities of indexing images: Using composed characteristic vectors, using parallel and independent index structures (for each descriptor or set of them) and using characteristic vectors sorted in sequential order. Thus, the first two forms have been widely studied and applied in literature, but there were no records of the third way has even been explored. So this thesis also proposes to index using a sequential structure of descriptors and also the order of these descriptors should be based on the relationship that exists between each descriptor and semantics of the users. Finally, the proposed index in this thesis revealed better than the traditional approachs and yet, was showed experimentally that the order in this sequence is important and there is a direct relationship between this order and the relationship of low-level descriptors with the semantics of the users

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O efeito da amonização com uréia (5,0% matéria seca) do feno de Brachiaria brizantha, com dois teores de umidade (15 ou 30% de umidade), associado a três fontes de urease (feno de capim Brachiaria decumbens, capim-elefante [Pennisetum purpureum] e leucena [Leucaena leucocephala]), foi avaliado. Foram determinados os teores de proteína bruta (PB), fração solúvel (A), frações de proteína verdadeira solúvel e insolúvel em borato fosfato (B1 e B2), fração de proteína potencialmente degradável (B3) e fração da proteína insolúvel em detergente ácido (C). Avaliaram-se os teores de fibra em detergente neutro (FDN), fibra em detergente ácido (FDA), celulose (CEL), hemicelulose (HEM) e lignina (LIG) e digestibilidade in vitro da matéria seca (DIVMS). O delineamento experimental foi o de blocos inteiramente casualizados, com 10 tratamentos (dois controles, 15 e 30% umidade, sem uréia e sem urease; dois controles, 15 e 30% umidade, com uréia e sem urease; seis combinações de fontes de urease e conteúdo de umidade) e três repetições. A amonização dos fenos com diferentes conteúdos de umidade, associados a fontes de urease, aumentou os teores de PB e da fração A, mas não afetou B1 e B2. Contudo, as frações B3 e C diminuíram em reposta à amonização. A aplicação de uréia nos fenos de 30% de umidade, associados ou não a fontes de urease, diminuiu os teores de FDN. A adição de fontes de urease não alterou os teores dos constituintes da parede celular, quando comparada aos tratamentos amonizados com uréia. Os tratamentos aplicados não proporcionaram efeitos consistentes sobre os teores de FDA e de CEL dos fenos e não afetaram os teores de LIG. A aplicação de uréia associada a 15 ou 30% de umidade foi favorável para aumentar o nitrogênio solúvel do feno de Brachiaria brizantha e diminuir o nitrogênio indisponível para o ruminante.

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Mangas 'Tommy Atkins' produzidas na região de Ibirá, São Paulo, foram pulverizadas na pré-colheita com cloreto de cálcio, nas concentrações de 0,0%, 2,5% e 5,0%, em três épocas de seu desenvolvimento (40; 60 e 90 dias após a floração) a fim de verificar a influência do cálcio na estrutura da parede celular destes frutos através de microscopia eletrônica de transmissão, imediatamente após a colheita e depois de 35 dias de armazenamento. Para fixar o material da polpa, utilizou-se metodologia descrita por Jacob e Gowanlock (1995). Nas condições experimentais, verificou-se que os frutos do tratamento-controle (sem cloreto de cálcio), no dia da colheita, já apresentavam desestruturação da parede celular e dissolução da lamela média (LM). A degradação da parede celular ocorre inicialmente na LM, levando à formação de espaços vazios bastante distintos, apresentando uma dissolução ainda maior, com o armazenamento prolongado (35 dias). Os frutos tratados com cloreto de cálcio a 5,0% apresentaram uma LM bem definida e ausência de espaços vazios, mesmo após o armazenamento, mostrando ser uma concentração efetiva na preservação da lamela média.

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This dissertation has the purpose to present a portable device named PlugData MG100G, equipped with a cellular module, to analyze the radiofrequency coverage in a GSM network situated in João Pessoa city, state of Paraíba, at four distinct regions. The equipment, originally, was developed to be used in fixed environments, so it was adapted so that it could be used in conditions of mobility. From the Mobile Measurement Reports (MMRs) RF coverage and the handover process are analyzed. The MMRs enable the identification of the serving cell and the list of the closest neighboring cells monitored by the mobile. This work analyses only data referent to the serving cell and the two closest neighboring cells. Inter-cell and intra-cell handovers are identified. The frequency planning and quality of service offered by the network related to the regions are discussed as well

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The development of wireless telecommunication in the last years has been great. It has been taking academics to conceive new ideas and techniques. Their aims are to increase the capacity and the quality of the system s services. Cells that are smaller every time, frequencies that are every time higher and environments that get more and more complex, all those facts deserve more accurate models the propagation prediction techniques are inserted in this context and results with a merger of error that is compatible with the next generations of communication systems. The objective of this Work is to present results of a propagation measurement campaign, aiming at pointing the characteristics of the mobile systems covering in the city of Natal (state of Rio Grande do Norte, Brazil). A mobile laboratory was set up, using the infra-structure available and frequently used by ANATEL. The measures were taken in three different areas: one characterized by high buildings, high relief, presence of trees and towers of different highs. These areas covered the city s central zone, a suburban / rural zone and a section of coast surrounded by sand dunes. It is important to highlight that the analysis was made taking into consideration the actual reality of cellular systems with covering ranges by reduced cells, with the intent of causing greater re-use of frequencies and greater capacity of telephone traffic. The predominance of telephone traffic by cell in the city of Natal occurs within a range inferior to 3 (three) km from the Radio-Base Station. The frequency band used was 800 MHz, corresponding to the control channels of the respective sites, which adopt the FSK modulation technique. This Dissertation starts by presenting a general vision of the models used for predicting propagation. Then, there is a description of the methodology used in the measuring, which were done using the same channels of control of the cellular system. The results obtained were compared with many existing prediction models, and some adaptations were developed by using regression techniques trying to obtain the most optimized solutions. Furthermore, according to regulations from the old Brazilian Holding Telebrás, a minimum covering of 90% of a determined previously area, in 90% of the time, must be obeyed when implanting cellular systems. For such value to be reached, considerations and studies involving the specific environment that is being covered are important. The objective of this work is contribute to this aspect

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Only 32% of the population of Natal is attended by sewage, while the remaining population use pits and septic tanks. The characterization of the contents of septic tanks and pits contributes to the performance of such system and may guide the decision on treatment of these contents. The main of this research is to characterize the contents of interior residential pits and septic tanks in the greater Natal, with the following specific goals: to develop and manufacture a sampler capable of collecting a representative sample of the entire column (the surface scum, the clarified liquid and sludge bottom); to compare the contents of the tanks with the pits; to compare the contents of the septage from vacuum trucks; to relate the composition content with socioeconomic characteristics of households; to compare the content in both chambers of the septic tanks in series; to assess the situation of the content before and six months after the cleanness; and ultimately propose a pilot scale plant for treatment of septage. Once the sampler was developed, samples were collected within 14 septic tanks and 10 pits in many districts of Natal. Medians of the 24 systems were obtained: temperature, pH, conductivity, oil and grease, total solids, total suspended solids and sediments of 28.0 °C, 6.95; 882 mS/cm, 75.2 mg/L; 10,169 mg/L, 6,509 mg/L and 175 mL/L respectively; 111.0 mgN/L for ammonia, 130.5 mgN/ L for organic nitrogen, 0.2 mgN/L for nitrite, 0.4 mg/L for nitrate; 8935 mgO2/L for COD, 29.2 mgP/L for total phosphorus, thermotolerant coliforms from 9.95 E +06 CFU/100mL helminth eggs and 9.2 eggs/L with a maximum concentration of 688 eggs/L and minimum of 0 eggs/L. Medians of organic nitrogen and TKN were significantly different between groups of tanks and pits. The systems with cleanness gap from 11 and 20 years presented the higher concentrations for most variables. The effluent from the toilets and bathrooms participate more effectively in contributing fractions of solids, alkalinity, nitrogen, COD, total phosphorus, thermotolerant coliforms and helminth eggs. The systems used by socioeconomics class with income from R$ 3,700.00 to R$ 7,600.00, presented higher concentrations for COD, nitrogen, solids and helminth eggs. The first of the two chambers had always presented higher concentrations over the second compartment. The analysis of variance for most variables, showed that the values of septic tanks, pits and septage from vacuum trucks belong to the same group. In the samples taken after cleanness, the median of pH and temperature increased, while alkalinity, COD, organic nitrogen, total phosphorus, ammonia and helminth eggs decreased. The oils and greases and thermotolerant coliforms had slightly varied due to the continuous release of sewage into the systems that maintained their steady state concentrations.

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La enseñanza de problemas se ha investigado en la didáctica de las ciencias naturales como un medio importante para desarrollar el aprendizaje de los conocimientos científicos y la formación de competencias básicas. Dada la importancia de los libros de texto para la enseñanza de la ciencia, con el fin de verificar el enfoque de la enseñanza con problemas en los libros de química, se procedió a una investigación realizada en las obras aprobadas en PNLD 2012, basado en el método de Análisis de Contenido. Se analizó el contenido de la estructura atómica, como marco teórico la perspectiva de la enseñanza problémica, basada en el materialismo histórico y dialéctico. Metodológicamente la investigación presenta un carácter cualitativo. Los resultados del análisis de contenido corroboraron la cuestiones de estudio iniciales relacionadas con la explicación centrándose en los problemas, lo que permitió inferir la elaboración de una Unidad Didactica basada en los métodos problémicos para la enseñanza de los modelos atómicos por la exposición problémica, la conversación heurística y la busca parcial, como forma de aproximar los estudiantes a la naturaleza de las ciencias naturales y contribuir al desarrollo de actitudes positivas en el aprendizaje de la química

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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