• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 238
  • 43
  • 41
  • 26
  • 24
  • 12
  • 10
  • 7
  • 6
  • 6
  • 4
  • 4
  • 4
  • 3
  • 3
  • Tagged with
  • 524
  • 250
  • 233
  • 107
  • 55
  • 52
  • 51
  • 48
  • 46
  • 43
  • 34
  • 33
  • 33
  • 32
  • 29
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
371

Aprimoramento das habilidades cognitivas de resolução de problemas com o apoio de um agente conversacional

Aguiar, Eliane Vigneron Barreto January 2011 (has links)
Uma questão que se apresenta relevante, nesta tese, é que na maioria das vezes, o estudante, principalmente, o novato, demonstra grande dificuldade na aprendizagem baseada na resolução de problemas. Portanto, este precisa de monitoração, isto exige um apoio de entidades ou pessoas mais experientes. Percebe-se que, muitas vezes, por falta de domínio na área do conhecimento tratada, o estudante não analisa minuciosamente os dados do problema para poder conduzir objetivamente cada etapa de solução. Várias habilidades cognitivas são exigidas durante o processo de resolução de problemas, como por exemplo, codificação, comparação e combinação, componentes cognitivos significativos detectados em estudantes talentosos. A aprendizagem por meio do processo de resolução de problemas num ambiente online pode ampliar o pensamento crítico e aprimorar a tomada de decisão. Nesta pesquisa, foi criado um agente conversacional chamado Blaze, com o intuito de apoiar o estudante durante a aprendizagem autorregulada baseada na resolução de problemas. O agente foi desenvolvido com a linguagem de marcação AIML (Artificial Intelligence Markup Language), tendo sua base de conhecimento construída por meio da elicitação e representação dos processos cognitivos dos estudantes talentosos, alunos medalhistas da Olimpíada Brasileira de Matemática das Escolas Públicas. Utilizou-se a técnica de Raciocínio Baseado em Casos para permitir a recuperação e reutilização de experiências passadas dos estudantes talentosos. Foram realizados tantos experimentos com outros estudantes de graus de escolaridades distintos (2ª série do ensino médio, Licenciatura em Ciências e Licenciatura em Matemática) com o objetivo de investigar o engajamento e o aprimoramento das habilidades cognitivas destes durante a resolução dos problemas com a assistência do agente conversacional Blaze. Nestes experimentos, alguns estudantes interagiram com o agente Blaze durante o processo de resolução de problemas matemáticos, enquanto outros trabalharam sozinhos na resolução dos mesmos problemas. Os resultados obtidos nos experimentos permitiram verificar que o apoio do agente conversacional Blaze, no contexto de uma aprendizagem autorregulada durante a resolução de problemas, contribuiu qualitativamente para o aprimoramento de diversas habilidades cognitivas, como por exemplo, pensamento crítico, pensamento criativo, raciocínio lógico, bem como, permitiu o uso da metacognição. / A relevant issue raised in this paper is that most times students, especially inexperienced ones, show great difficulty for learning based on problem solving. Therefore, such students need to be monitored, which requires support from entities or more experienced people. Many times we see that due to students’ lack of mastery of the field of knowledge addressed, they fail to thoroughly analyze the problem data so as to objectively handle each stage of the solution. Several cognitive skills are required during the problem-solving process, such as coding, and comparison and combination, significant cognitive components detected in talented students. Learning by means of a problem-solving process in an online environment is capable of expanding critical thinking and improving students’ decision-making skills. In this research, a conversational agent we call Blaze was created in an effort to help students during their self-regulated, problem solving-based learning. The agent was developed via the AIML (Artificial Intelligence Markup Language), and its knowledge base was put together by means of eliciting and representing the cognitive processes of talented students, students who had won medals at the Brazilian Public School Mathematics Olympic Games. We used the Case-Based Reasoning technique to enable us to recover and reuse the talented students’ past experiences. Some other experiments were carried out with other students from various schooling levels (high school sophomores, and Science and Math undergrads) in order to look into those students’ engagement and improvement of their cognitive skills as they solved problems assisted by the Blaze conversational agent. In those experiments, some students interacted with the Blaze agent during the math problem-solving process, while other students worked alone on solving the same problems. The results obtained from the experiments allowed us to find that the support from the Blaze conversational agent, in the context of self-regulated learning during problem-solving, qualitatively helped the students improve their several cognitive skills, such as critical thinking, creative thinking, and logic reasoning, besides enabling the use of meta-cognition.
372

ANÁLISE DO RISCO DOS CONTRATOS DE ENERGIA ELÉTRICA DAS CONCESSIONÁRIAS DE DISTRIBUIÇÃO / ANALYSIS OF THE RISK OF CONTRACTS OF ELECTRICAL ENERGY CONCESSIONAIRES DISTRIBUTION

Mendonça, Fernando José Moreira 19 March 2008 (has links)
Made available in DSpace on 2016-08-17T14:52:44Z (GMT). No. of bitstreams: 1 Fernado Jose Moreira Mendonca.pdf: 1350313 bytes, checksum: e72c7c0c53c0eb514a42a7aae28f2cde (MD5) Previous issue date: 2008-03-19 / This work presents an analysis of the new environment of purchasing electric energy, as well as the study s methodology for contracting. The objective of the distribution agents is to keep, in the current process of decision-making for contracting energy, a strategic purchase of energy within the limits of repasse the tariffs of electric energy. It proposes a strategy considering a number of actions to minimize the risks of sub and over hiring in the new environment of the electric sector. It is also held a detailed analysis of the parameters related to the procedures of contracting electrical power to enable a better understanding of the risks inherent in this process. The proposed strategy is applied to case studies and the results demonstrate the usefulness of the proposed methodology that minimizes the risk of contracting. The analysis of the results of the strategies of hiring concluded that the comfort level of coverage should be maintained in the level of 101.5%, in face of the possibilities of variations of scenarios of market forecast. / Neste trabalho é apresentada uma análise do novo ambiente de contratação de energia elétrica, bem como o estudo da metodologia de contratação. O objetivo dos agentes de distribuição é manter, no processo atual de tomada de decisão para a contratação de energia, uma estratégica de compra de energia dentro dos limites de repasse às tarifas de energia elétrica. É proposta uma estratégia considerando um conjunto de ações no sentido de minimizar os riscos de sub e sobre contratação dentro do novo ambiente do setor elétrico. Igualmente é realizada uma análise detalhada dos parâmetros relacionados com o procedimento de contratos de energia elétrica para permitir um melhor entendimento dos riscos inerentes neste processo. A estratégia proposta é aplicada a estudos de caso e os resultados demonstram a utilidade da metodologia proposta que minimiza os riscos de contratação. Da análise dos resultados das estratégias de contratação conclui-se que o nível de conforto de cobertura deve manter no patamar de 101,5%, em face das possibilidades de variações de cenários de previsão de mercado.
373

Comercialização de bioeletricidade no ambiente de contratação livre pelas usinas do setor sucroenergético da região de Ribeirão Preto: panorama e análise das ameaças e oportunidades / Comercialitation of bioelectricity in the free contracting environment by the sugar cane mills of the sugar-energy sector from the region of Ribeirão Preto: scenery and analysis of opportunities e threats

Iraci de Souza João 24 February 2010 (has links)
O mercado brasileiro de eletricidade enfrentou nos últimos anos, crises de abastecimento, devido ao maior crescimento da demanda em relação à oferta. Derivado da falta de investimentos em infraestrutura e da concentração da matriz energética em hidroeletricidade, esse cenário pode ser minimizado pela bioeletricidade cogerada a partir do bagaço da cana. Porém, a efetiva exploração de seu potencial, depende das usinas reconhecerem-na como produto viável e lucrativo. Nesse sentido, o objetivo deste estudo foi caracterizar a comercialização de bioeletricidade no ACL e compará-la com o ACR identificando ameaças, oportunidades, pontos fortes e fracos de cada um. Realizou-se entrevistas com gestores: de quatro usinas sucroenergéticas, da distribuidora de energia local e de um consumidor livre. Utilizando-se a análise SWOT e PEST e as técnicas de análise de conteúdo e correspondência os dados foram trabalhados. Os resultados indicaram que a principal vantagem do ACR é a segurança quanto ao preço da energia e a desvantagem é a inflexibilidade do contrato aliado a altas penalidades. O ponto forte relevante do ACL é a flexibilidade na definição de prazo, preço e quantidade e a fraqueza é a volatilidade do preço. Devido a essas características os agentes tendem a atuar nos dois mercados, adotando como estrutura de governança principal o mercado e as formas híbridas em segundo plano. Constatou-se ainda a necessidade da atuação governamental como incentivador de fontes renováveis e provedor de soluções para entraves como a conexão a rede de transmissão, fraqueza dos dois mercados, e a falta de um ambiente adequado de comercialização. / In recent years, the Brazilian electricity market has gone through provision crises, due to the greater increase in demand with regard to supplies. Resulting from the lack of infrastructural investments and the concentration of the energy matrix in hydroelectricity, this scenario can be minimized by the bioelectricity coproduced based on sugar cane pulp. However, the effective exploration of its potential depends on sugar cane mills acknowledging it as a viable and profitable product. This research aimed to characterize bioelectricity commerce in a Free Contracting Environment (ACL) and compare it with a Regulated Contracting Environment (ACR), identifying the threats, opportunities, strong and weak points of each. Interviews were held with managers: of four sugar-electricity mills, the local energy distributor and a free consumer. Data were processed using SWOT and PEST analysis, as well as content and correspondence analysis techniques. The results indicated that the main advantage of ACR is security about energy prices, while the disadvantage is the contracts lack of flexibility, in combination with high penalties. The relevant strong point of ACL is the flexibility to define term, price and quantity, and the weakness is price volatility. Due to these characteristics, agents tend to act in both markets, adopting the market as the main governance structure and hybrid forms at a secondary level. Government action is needed to encourage renewable energy sources and provide solutions to bottlenecks like connection with the transmission network, weakness of both markets and lack of an adequate trading environment.
374

Percepção musical e a escola tradicional no Brasil : reflexões sobre o ensino e propostas para melhoria no contexto universitário / Musical perception : situation of the discipline with in undergraduate music courses in Brazil

Otutumi, Cristiane Hatsue Vital, 1978- 07 May 2013 (has links)
Orientador: Ricardo Goldemberg / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Artes / Made available in DSpace on 2018-08-23T08:24:22Z (GMT). No. of bitstreams: 1 Otutumi_CristianeHatsueVital_D.pdf: 31212880 bytes, checksum: 5294b602ed332cd475faae46bc26d277 (MD5) Previous issue date: 2013 / Resumo: Esta pesquisa teve como objetivos maiores aprofundar discussões sobre o ensino na disciplina Percepção Musical e propor a teoria da Autorregulação da aprendizagem como norte reflexivo da matéria, tendo, ambas as ações, o intuito da sua melhoria no contexto universitário. Para isso, no capítulo um, buscou-se discutir sobre as dificuldades dos docentes - tal como a heterogeneidade de níveis de conhecimento e a falta de motivação dos alunos ao estudo -, bem como levantados cinco aspectos da escola tradicional mais citados e problematizados por autores brasileiros há cerca de dez anos. No capítulo dois, foi proposta a Autorregulação da aprendizagem em uma perspectiva sociocognitiva para as ações na disciplina, mas, também comentadas diferentes formas de estudar no meio acadêmico musical, desde recursos conhecidos como a monitoria, internet, incentivo à pesquisa, à realização de projetos vinculados à sala de aula. O capítulo três traz a pesquisa-ação como metodologia adotada, e a narrativa das duas fases de intervenção pedagógica desenvolvidas com alunos ingressantes de duas instituições públicas brasileiras, da região Sudeste e Sul do país. Foram elaboradas duas disciplinas de Percepção Musical 1 da graduação, orientadas pela Autorregulação da aprendizagem em caráter de infusão curricular, nas quais foram oferecidas diferentes atividades e textos para reflexão, em um sistema que contemplou ações voluntárias e obrigatórias. Os resultados, em depoimentos e atividades realizados pelos alunos, foram organizados, tratados e interpretados segundo a Análise de Conteúdo. Trazem informações significativas demonstrando riqueza de interação com essa nova perspectiva na matéria, com os conteúdos de autorregulação, e mostrando ser possível amenizar o caráter excessivamente técnico ou instrumental geralmente presente na disciplina. Por fim, é apresentada a autoavaliação da pesquisadora, oportunizando e revelando maior conscientização sobre o ensinar e o aprender nesse ambiente musical / Abstract: This research had as main objectives to deepen discussions on education in the discipline of Musical Perception and to propose the theory of self-regulated learning as reflective lead of matter, both aiming the purpose of their improvement in the university context. In this regard, in chapter one, we tried to discuss the difficulties of teachers - such as the heterogeneity of levels of knowledge and lack of motivation of the students to study - as well as, raised five aspects of traditional school cited by Brazilian authors about ten years. In chapter two, it was proposed the self-regulated learning in a socio-cognitive perspective for actions in the discipline, but also remark different ways of studying in the musical academic environment, since known resources as guidance personnel (monitory), internet, encouraging research, the development of projects linked to the classroom. Chapter three brings actionresearch as a methodology, and the narrative of the two phases of pedagogical intervention developed with students entering two Brazilian public institutions, from south and south-east regions. Were prepared two disciplines of Musical Perception 1 of graduation, guided by self-regulated learning on an infusion curriculum way, in which were offered different activities and texts for reflection in a system that included voluntary and compulsory actions. The results, in statements and activities made by the students, were organized, processed and interpreted according to the Content Analysis. Bring meaningful information demonstrating wealth of interaction with this new perspective, with the contents of self-regulation, and showing possible lessen of the technical or instrumental character generally present in the discipline. Finally, we present the self-rated researcher, revealing greater awareness of teaching and learning in this musical environment / Doutorado / Fundamentos Teoricos / Doutora em Música
375

Oppimisen itsesäätelyn ilmeneminen ja kehittymisen tukeminen alakoulun oppimiskontekstissa

Kontturi, H. (Heikki) 26 January 2016 (has links)
Abstract This study explores self-regulated learning (SRL) in the learning context of a primary school. The research focus is on the occurrence and promotion of SRL. The research is a qualitative case study. The theoretical foundation rests on research into SRL and its promotion. The research context was provided by the pedagogical development of the UBIKO project, which took place at the Oulu University Teacher Training School (Oulun normaalikoulu). The data consists of the structured diaries of students from grades 4 and 5 (N = 90) and the thematic interviews and descriptions of the learning context by their teachers (N = 6). The analysis, carried out to clarify the meaning of the learning context, was boosted by samples based on the Motivated Strategies for Learning Questionnaire (MSLQ) questionnaire. The results indicate that pupils are aware of their learning and they exploit different learning strategies during their learning. The modification of the learning context has a different impact on the motivation and strategy use of strategically low and high pupils. SRL can be promoted by creating a learning context that supports pupils in their planning, monitoring and evaluation processes. In terms of school development it is not enough to concentrate on single supportive elements – the systemic development the learning context (i.e. learning situation, physical environment and social architecture) also needs to be considered. The findings of this study contribute to understanding the skills and promotion of SRL among primary school pupils. The results offer research-based support for teachers, teacher trainees and school developers to meet the challenges of 21st century education. / Tiivistelmä Väitöstutkimus tarkastelee oppimisen itsesäätelyä alakoulun oppimiskontekstissa. Tutkimuskohteina ovat oppimisen itsesäätelyn ilmeneminen sekä sen kehittymisen tukeminen. Tutkimus on laadullinen tapaustutkimus, jonka teoreettinen tausta on oppimisen itsesäätelyn ja sen kehittymisen tutkimuksessa. Tutkimuskontekstina toimi Oulun yliopiston harjoittelukoulussa (Oulun normaalikoulu) toteutunut UBIKO-kehittämishanke, jonka aikana tapahtuneeseen pedagogiseen kehittämiseen tutkimus kohdentuu. Tutkimusaineisto koostuu 4.–5.-luokkalaisilta oppilailta (N = 90) kerätyistä strukturoiduista päiväkirjoista sekä heidän opettajiensa (N = 6) oppimiskontekstia kuvaavista raporteista ja teemahaastatteluista. Lisäksi oppimiskontekstin merkityksen analyysia syvennettiin tarkastelemalla oppimisen itsesäätelyn ilmenemisen muutoksia Motivated Strategies for Learning Questionnaire (MSLQ) -kyselyn avulla oppilasjoukosta seulottujen otosten osalta. Tutkimustulokset osoittavat oppilaiden olevan tietoisia oppimiseensa liittyvistä tekijöistä, ja he hyödyntävät oppimisessaan erilaisia oppimisstrategioita. Tulosten perusteella oppimiskontekstissa tapahtuvat muutokset vaikuttavat eri tavoin strategisesti heikkojen ja vahvojen oppilaiden motivaatioon ja strategiseen toimintaan. Oppimisen itsesäätelyn kehittymistä voidaan tukea luomalla oppimiskontekstiin piirteitä, jotka vahvistavat oppilaiden oman toiminnan suunnittelua, tarkkailua ja arviointia. Koulun kehittämisen näkökulmasta yksittäisten elementtien lisäksi on huomioitava se systeeminen kokonaisuus, joka oppimistilanteen, fyysisen oppimisympäristön sekä sosiaalisen vuorovaikutuksen kautta oppimiskontekstiin muodostuu. Väitöstutkimuksen tulokset ja tutkimuskontekstin yksityiskohtainen esittely lisäävät ymmärrystä alakouluikäisten oppimisen itsesäätelytaidoista ja niiden kehittymisen tukemisesta. Tulokset auttavat opettajia, opettajankouluttajia ja muita koulun kehittäjiä vastaamaan tutkimusperustaisesti niihin vaatimuksiin, joita 2000-luvun koulutukselle on kansainvälisestikin asetettu.
376

Young children’s success in learning situations:actions, views and appraisals in learning contexts

Mykkänen, A. (Arttu) 19 April 2016 (has links)
Abstract This study investigates young children’s views of successful learning situations in their classroom activities and factors that contribute to their achievement in those situations. It is investigated how self-regulated learning is supported in these situations and how children appraise support as part of their success. The study consists of three different data sets that are reported in three empirical articles. The first empirical study investigated resilience displayed by young children in dyadic task performance. The second empirical study investigated views and appraisals that primary school children give to their success in classroom learning activities and how self-regulated learning is supported in the classrooms. The third empirical study investigated how primary school children appraise the reasons for their peers’ successes in learning situations. The data collection methods include video observations, stimulated recall interviews and photo elicitation interviews. The results of this dissertation indicated that success in learning activities results from individual and external factors. Among the individual assets that children bring to learning situations, the support that children receive from their teachers and peers were crucial for successful achievement. This study showed that, in general, the children’s self-regulated learning was supported in the classroom, especially through the support from a teacher and non-threatening evaluation. Children described their success through concrete actions that they took in the situations, such as the ability to accomplish the particular tasks or doing academic activities in order to achieve the task. The methodological findings indicate that it is possible to develop child-centred participatory methods in learning research. Results of this study contribute to the discussion of how successful learning experiences and self-regulated learning can be supported in the first years of primary school. / Tiivistelmä Tässä väitöstutkimuksessa tarkastellaan pienten lasten onnistumisen kokemuksia ja niiden syitä aidoissa oppimistilanteissa. Tavoitteena on selvittää, kuinka itsesäätöistä oppimista tuetaan ja kuinka lapset näkevät saamansa tuen auttavan heitä onnistumaan. Tutkimus koostuu kolmen aineiston analyyseista jotka on raportoitu kolmessa empiirisessä artikkelissa. Ensimmäinen tutkimus tarkasteli pienten lasten osoittamaa sinnikkyyttä yksilö- ja paritehtävässä. Toinen tutkimus selvitti, kuinka alakouluikäiset lapset selittivät onnistumistaan koululuokan oppimistilanteissa ja kuinka itsesäätöistä oppimista tuettiin kyseisissä tilanteissa. Kolmas tutkimus tarkasteli, kuinka alakouluikäiset oppilaat selittivät koulukavereidensa onnistumista oppimisessa. Tutkimusaineisto koostuu videohavainnoinneista sekä videoin ja valokuvin tuetuista haastatteluista. Tämän tutkimuksen tulokset osoittavat, että koululuokassa tapahtuvaan onnistumiseen vaikuttavat sekä ulkoiset että sisäiset tekijät. Sisäisiä tekijöitä ovat lasten yksilölliset taidot, kuten sinnikäs työskentely ja kyky suorittaa tehtävä onnistuneesti. Selittäessään omia ja kavereidensa onnistumisia lapset kuvailivat onnistumista konkreettisten toimien kautta. Lapset näkivät onnistumisen johtuneen toimista joita he tekivät tehtävien aikana, kuten tehtävien aktiivinen suorittaminen ja kyvykkyys suoriutua tehtävistä onnistuneesti. Ulkoisiin tekijöihin kuuluu tuki, jota lapset saavat oppimisen aikana. Tutkimuksessa havaittiin, että seuratuissa luokkahuoneissa lasten itsesäätöistä oppimista tukivat erityisesti opettajien tarjoama apu ja kannustava arviointi, jotka loivat luokkaan ymmärtävän ja rohkaisevan ilmapiirin. Metodologisesti tämä tutkimus näyttää, että oppimisen tutkimuksessa on mahdollista kehittää lapsilähtöisiä, osallistavia tutkimusmenetelmiä. Tutkimuksen tulokset lisäävät tietoa siitä, miten lasten onnistumisen kokemuksia ja itsesäätöistä oppimista voidaan tukea jokapäiväisissä luokkahuonetilanteissa.
377

Deductions from employees’ remuneration: seeking clarity in the law

Cato, Cara January 2009 (has links)
Magister Philosophiae - MPhil / Sectoral Determination 9,1 Wholesale and Retail Sector echoes the wording found in the Basic Conditions of Employment Act2 when it comes to the section pertaining to deductions from employees’ remuneration. It is unclear how an employer may lawfully make a deduction (other than those required by law) from an employee’s remuneration in order to recover costs such as till shortages, stock losses and improper notice. Loss and damages are common problems faced not only by retailers but by all employers, yet the two governing bodies, that is, the Department of Labour and the CCMA, fail to offer any assistance to the employer in this regard. The law is unfairly biased against the employer, who may be financially unable to recover from losses caused by an employee and may face closure should it be unable to recover losses suffered. The two remedies available to the employer are civil action and criminal action against the employee. However, both have proven to be inadequate for recovering losses incurred. Furthermore, the employer will have already incurred losses and therefore can ill afford the money or the time to pursue these options. The Small Claims Court does offer some relief to a smaller employer wanting to claim to a maximum of R7000, but companies are excluded from this mechanism as the rules of the Small Claims Court specifically exclude them from using this forum. In this study, I will look at the common law principle of offset to see whether it can be applied to employers making deductions against employees for loss or damage. Notice is a quantifiable amount and is a legal debt; therefore. it should be able to be applied as an offset. Two subsections deal with deductions; after looking carefully at the wording of theses subsections I will try to determine whether the one is alternate to the other, or whether the narrow interpretation that the Department of Labour gives to the statute is accurate. A narrow interpretation of the law states that the employee must sign an acknowledgement of debt. However, employees often refuse to sign an acknowledgement of debt, thereby frustrating the law. Could this possibly have been the intentions of the drafters? Surely not, yet the Department of Labour, by having a narrow interpretation of the law, see it as such and as a result the employer is left out of pocket. In this mini-thesis, I will look at the way the law should be interpreted and the way it should be applied in practice. 1 Sectoral Determination 9: Wholesale and Retail Sector, Government Gazette No. 24207 2 The Basic Conditions of Employment Act 75 of 1997 What problems does this ambiguity create? Some problems could include a higher case load for the Department of Labour, demotivated employees, increased tension in the workplace and frustrated employers. I also consider comparative labour law to see if other countries faced with similar situations have made any allowances for such circumstances. Aims of this mini-thesis: 1. To highlight the problems and ambiguities in the interpretation and application of section 34 of the Basic Conditions of Employment Act (BCEA)3 and section 8 of the Sectoral Determination 9(SD9)4 2. To recommend, propose and encourage a practical solution for employers to implement in the workplace 3. To improve the situation for employers under the current structure. 4. To lead the legislature drafters to amend or redraft these sections
378

Characterization Of Down Regulated Genes In Astrocytoma

Bhanja, Poulomi 05 1900 (has links) (PDF)
Gliomas are the most common primary brain tumors and include astrocytomas, oligodendrogliomas and oligoastrocytomas. Astrocytomas have a high frequency of occurrence as compared to the other gliomas and several studies including ours have focused on understanding the etiology, biology and genetics of this disease. Based on the degree of malignancy, astrocytomas have been graded from I to IV. Grade I or pilocytic astrocytomas are benign tumors and have limited infiltration. On the contrary, Grade II-IV astrocytomas also referred to as diffusely infiltrating astrocytomas (DA, Grade II), anaplastic astrocytomas (AA, Grade III) and glioblastoma multiforme (GBM, Grade IV), have the tendency of diffusely infiltrating the normal brain parenchyma. GBM is characterized by uncontrolled proliferation and resistance to apoptosis, rampant invasion, recalcitrance to most established therapies etc which makes them the most aggressive of all gliomas with a median survival of about 12 months. This makes it imperative to initiate further studies to understand the molecular basis of this disease. Gene expression profiling studies have been central to this effort. In recent years, several Microarray studies have provided crucial insights into the biological role of novel genes not previously associated with astrocytomas. In a previous Microarray study, several differentially regulated genes in astrocytoma were identified in our laboratory. In addition to many up regulated genes, several down regulated genes were also identified in this study. Down regulated genes are interesting to study because of their relevance as possible tumor suppressor genes. Hence, we decided to characterize the regulation and functional significance of few down regulated genes. The specific objectives of the study are as follows 1)To validate novel down‐regulated genes in astrocytomas identified by a previous Microarray study. 2)To understand the mechanism of down-regulation of a few selected gene. 3)Functional characterization of DIRAS2, a novel astrocytoma down‐regulated gene with respect to its possible role in astrocytoma progression. Towards these objectives, we identified 21 genes as differentially down-regulated across all grades of astrocytoma based on a previous Microarray study from our lab and data from literature. Real time qRT-PCR analysis performed on these 21 genes confirmed their down-regulation in all grades of astrocytoma as compared to normal brain tissues. From these 21 genes, we short-listed 10 of the most consistently down-regulated genes for further analysis. These genes were DIRAS2, IGFBP9, MAL2, MBP, OLFM1, PACSIN1, RAB26, SYT1, SYT5 and VSNL1. We also confirmed the expression of two of the genes, OLFM1 and RAB26 at the protein level by performing immunohistochemical analysis on an independent set of 38 tissues that included 10 normal tissues and 28 tissues from different grades of astrocytoma. OLFM1 was found to be down-regulated in a grade specific manner. RAB26 expression was found to be strikingly high in all the low grade astrocytomas in comparison to high grade astrocytomas which made it an interesting gene to study functionally. On functional characterization, we found that RAB26 over‐expressing LN229 cells showed significantly reduced invasion compared to the vector transfected cells suggesting RAB26 could have a tumor-suppressing role in astrocytomas. In order to investigate whether transcriptional modulation could play a role in the down-regulation of these 10 genes, we searched for transcription factor binding sites in approximately 2kb 5’ flanking region of each gene. Intriguingly one or more PAX6 binding sites were present in all their promoters. In light of the fact that PAX6 has been proposed as a tumor‐suppressor in astrocytomas, we predicted that some of these genes could be targets of PAX6 transactivation and could possibly mediate some of the tumor‐suppressive actions of PAX6. PAX6 has been proposed as a down stream target of Notch signaling in the context of eye development. Similar to this observation, upon activation of Notch signaling with a virus expressing human intracellular domain of Notch (Ad-NIC-1), PAX6 expression was found to be induced in glioma cell lines suggesting PAX6 to be a novel NOTCH target in astrocytomas. In addition, Ad-NIC-1 infection could also induce the expression of OLFM1, RAB26, MAL2 and MBP in U343 cells. We could also demonstrate that Ad-NIC-1 co-operates with PAX6 in the regulation of these four genes in cell lines expressing endogenous PAX6, namely U343 and U251. Intriguingly, in a cell-line lacking PAX6 expression (LN229), Ad-NIC-1 could not induce OLFM1, RAB26 and MBP, although we could see induction of MAL2. Interestingly, PAX6 overexpression in LN229 cells in the absence of Ad-NIC-1 could induce OLFM1, RAB26 and MAL2. In contrast, infection of Ad-NIC-1 on the PAX6 over-expressing cells seemed to have an antagonistic effect on the expression of OLFM1, RAB26 and MBP, suggesting that Ad-NIC-1 antagonizes PAX6 actions in these cells. Ad-NIC-1 infection resulted in increased apoptosis in a PAX6 independent manner in U343 cells, which as previously mentioned has high levels of PAX6 endogenous expression. Conversely, Ad-NIC-1 could not induce apoptosis in LN229 cells, which has negligible expression of PAX6. We could also demonstrate that apoptosis induced in U343 cells could be in a p53 dependent manner. Activation of AMPK pathway and inhibition of the mTOR pathway as a consequence of p53 induction could also explain the Ad-NIC-1 mediated apoptosis that was seen in these cells. Thus, we have proposed that Notch signaling could possibly have a tumor-suppressing role in the presence of PAX6. We also suggest that down-regulation of OLFM1, RAB26, MAL2 and MBP via the NOTCH-PAX6 axis could be a possible molecular mechanism for the down-regulation of these genes. With respect to the third objective, we sought to characterize DIRAS2 with respect to its function in astrocytomas. DIRAS2 was identified as a down‐regulated gene in all grades of astrocytoma by our Microarray study. We were also able to validate the down‐regulation of DIRAS2 in all grades of astrocytomas. DIRAS2 also bears significant homology to RIG1 (also known as DIRAS1), which has been proposed as a tumor suppressor gene in astrocytomas. In the light of these data, we predicted that DIRAS2 could be a tumor suppressor gene in astrocytomas. Overexpression of DIRAS2 in two glioma cell lines U87 and C6 did not reveal any appreciable change in proliferation. Strikingly when the DIRAS2 over-expressing clones were grown in the absence of serum, there was marked increase in proliferation with respect to vector transfected clones along with a distinct change in morphology. Decorin expression in the DIRAS2 over-expressing clones was found to be up regulated and could be responsible for the altered morphology as well as enhanced viability in absence of serum. Interestingly along with Decorin expression, we also observed an increase in phosphor-SMAD2 levels indicative of activated TGF‐β signaling in the DIRAS2 over-expressing clones in the absence of serum. In the soft agar and migration/invasion assays, the results across the two cell lines, U87 and C6 were contrasting. DIRAS2 over-expressing clones of U87 cells formed visibly larger and increased number of colonies as compared to vector transfected clones and there was about a three fold increase in invasion with respect to that seen in vector transfected clones in the matrigel invasion assay. On the other hand, DIRAS2 over-expressing C6 clones formed colonies of smaller size compared to vector transfected clones and a marked decrease in migration was observed in the DIRAS2 over-expressing clones of C6. The discrepancies in the results in these two cell lines could be attributed to the presence of other regulators of DIRAS2 function unique to each of the two cell lines. Although in the present study, the results with respect to its predicted function as a tumor-suppressor gene has not been conclusive, the role of DIRAS2 in tumorigenesis may depend on the cellular context in which the protein is expressed. Overall in this study, we have identified a novel down regulated gene signature in astrocytomas consisting of OLFM1, RAB26, MAL2 and MBP. Furthermore, we have proposed that inhibition of NOTCH and PAX6 signaling pathways could be responsible for the down-regulated expression of OLFM1, RAB26, MAL2 and MBP in astrocytomas. Collectively, these results suggest that astrocytomas with activated Notch1 and/or Pax6 signaling could have good prognosis due to the tumor suppressive actions of OLFM1, RAB26, MAL2 and MBP
379

The Effectiveness of Using Lego Mindstorms Robotics Activities to Influence Self-regulated Learning in a University Introductory Computer Programming Course.

McWhorter, William Isaac 05 1900 (has links)
The research described in this dissertation examines the possible link between self-regulated learning and LEGO Mindstorms robotics activities in teaching concepts in an introductory university computer programming course. The areas of student motivation, learning strategies, and mastery of course objectives are investigated. In all three cases analysis failed to reveal any statistically significant differences between the traditional control group and the experimental LEGO Mindstorms group as measured by the Motivated Strategies for Learning Questionnaire and course exams. Possible reasons for the lack of positive results include technical problems and limitations of the LEGO Mindstorms systems, limited number and availability of robots outside of class, limited amount of time during the semester for the robotics activities, and a possible difference in effectiveness based on gender. Responses to student follow-up questions, however, suggest that at least some of the students really enjoyed the LEGO activities. As with any teaching tool or activity, there are numerous ways in which LEGO Mindstorms can be incorporated into learning. This study explores whether or not LEGO Mindstorms are an effective tool for teaching introductory computer programming at the university level and how these systems can best be utilized.
380

Dejefors kraftverks inverkan på den lekvandrande laxens möjlighet till nedströmsvandring i Klarälven / Downstream salmon kelt migration past Dejefors hydropower plant in the river Klarälven

Hansson Järnving, Rebecca January 2021 (has links)
Under hösten leker en inhemsk population av Atlantisk lax (Salmo salar) i Klarälven, Sverige, för att därefter vandra nedströms tillbaka till sjön Vänern. Vid älvens andra kraftverk sett från Vänerns mynning, Dejefors kraftverk, finns det planer på att ersätta ett av kraftverken mot ett nytt och det finns därför ett behov av att ta reda på hur laxens nedströmsvandring påverkas av det kraftverket som finns där i dag. Då alla kraftverk i Klarälven saknar fiskpassagelösningar är det extra viktigt att följa upp laxarnas passageöverlevnad under vandringen. Avsikten med denna studie var därför att ta reda på hur laxen rörde sig runt kraftverket, hur väl de klarade av att passera kraftverket beroende av vilken passageväg de tog och vilka faktorer som påverkade passageframgången. Under september 2020 fångades 40 laxindivider in när de var på väg uppströms inför leken. De mättes och märktes med telemetrisändare för att sedan transporteras uppströms och släppas ut nedanför kraftverket i Munkfors, varifrån deras nedströmsvandring förbi Dejefors kraftverk följdes och analyserades med hjälp av akustisk telemetri. Resultatet visade att det inte fanns någon signifikant skillnad mellan kön för när laxarna påbörjade sin nedströmsvandring. Kraftverket visade sig dock fördröja laxarnas nedströmsvandring då det tog längre tid för dem att passera kraftverket än vad det tagit dem att simma ner dit i den fritt strömmande delen av älven. Av de 31 laxar som anlände till Deje så passerade 27 av dem kraftverket, varav 13 individer överlevde (48 %). Överlevnaden var högre för individer som passerade via spillutskoven (10 av 12) än turbinerna (3 av 15). Det fanns en signifikant skillnad i mortalitet vid kraftverkspassage beroende på laxens längd och passageväg; långa individer hade en högre mortalitet (73 %) än kortare (25 %) och passagevägen hade en signifikant effekt på mortaliteten. Resultatet visar tydligt på ett behov av åtgärder för att förbättra överlevnaden hos lax vid passage av Dejefors kraftverk. Lösningar för att få fisken att helt undvika turbinerna och istället välja en annan passageväg vore troligen den bästa och effektivaste lösningen för att öka laxens överlevnad under nedströmsvandringen. / During autumn, the endemic Atlantic salmon (Salmo salar) migrate upstream to spawn in the river Klarälven, Sweden, after which they migrate downstream back to Lake Vänern. There are plans to remove one of the power houses in Deje, and replace it with a new power house, and before that happens it is important to study the downstream passage conditions at the site. As all power plants in Klarälven lack fish passage solutions, it is important to follow up the salmon passage survival during the migration. The purpose of this study was therefore to study how downstream migrating salmon negotiate the power plant, the route-specific passage survival and what factors that could affect their passage success. In September 2020, 40 upstream migrating salmon individuals were caught, measured and tagged after which they were transported and released below the power plant in Munkfors. Their downstream migration past Dejefors power plant was studied and analyzed using acoustic telemetry. The results showed that there was no significant difference between sexes in regards of downstream migration timing. However, the power plant turned out to delay downstream migrating salmon as it took longer time for them to pass the power plant than it took them to swim down the free-flowing part of the river. Of the 31 salmon that arrived in Deje, 27 passed the power plant, of which 13 individuals survived (48%). The survival rate was higher for individuals passing via spillways (10 of 12) than turbines (3 of 15). There was a significant difference in mortality rate at power plant passage depending on the length and passage route of the salmon. Large individuals suffered a higher mortality (11 of 15) than short (3 of 12) and a larger proportion of the salmon died when passing through the turbines than through spill gates. Based on the results, there was a clear need for improved survival rates for salmon passing the Dejefors power plant. The design of the turbines could be changed for increased survival, but at the same time other solutions that will make it possible for fish to avoid the turbines and instead choose another passageway would probably be a better and more efficient solution to increase the survival of the salmon during their downstream migration.

Page generated in 0.0663 seconds