• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2865
  • 995
  • 609
  • 477
  • 177
  • 176
  • 127
  • 102
  • 84
  • 72
  • 57
  • 50
  • 48
  • 42
  • 19
  • Tagged with
  • 6787
  • 553
  • 507
  • 481
  • 470
  • 402
  • 396
  • 340
  • 335
  • 322
  • 301
  • 297
  • 295
  • 241
  • 230
  • 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.
81

Upplevelsen av att arbeta inom ett personalkooperativt företag : Skillnaden mellan medlem och anställd

hedman, ulrika January 2014 (has links)
Studien undersökte hur arbetet inom den personalkooperativa verksamheten upplevdes av medlemmar och anställda, samt skillnaden dem emellan. I denna studie användes personalkooperativ för att det där ingår både medlemmar, som är ägare av kooperativet, och anställda. Syftet uppnåddes genom intervjuer där tre frågeställningar användes: vad upplevda erfarenheten är av att ingå i ett personalkooperativ, hur företagets handlingar stämmer överens med de aktuella kooperativens sju principer, samt hur deltagarna förhåller sig till Maslows behov.  Resultatet visade dels att möjligheten att själv kunna påverka arbetet var skälet till varför deltagarna valt att ingå i ett kooperativ. Dock angavs som negativt saknaden av en chef och den bristande ekonomin. Skillnaden mellan medlemmar och anställda framgick genom att medlemmarna fokuserade mer på verksamheten som helhet medan de anställda lade fokus på interaktionen mellan kollegor. Validiteten försvagades då urvalet skedde via målinriktat urval.
82

HIGH-SPEED CO-PROCESSORS BASED ON REDUNDANT NUMBER SYSTEMS

2015 February 1900 (has links)
There is a growing demand for high-speed arithmetic co-processors for use in applications with computationally intensive tasks. For instance, Fast Fourier Transform (FFT) co-processors are used in real-time multimedia services and financial applications use decimal co-processors to perform large amounts of decimal computations. Using redundant number systems to eliminate word-wide carry propagation within interim operations is a well-known technique to increase the speed of arithmetic hardware units. Redundant number systems are mostly useful in applications where many consecutive arithmetic operations are performed prior to the final result, making it advantageous for arithmetic co-processors. This thesis discusses the implementation of two popular arithmetic co-processors based on redundant number systems: namely, the binary FFT co-processor and the decimal arithmetic co-processor. FFT co-processors consist of several consecutive multipliers and adders over complex numbers. FFT architectures are implemented based on fixed-point and floating-point arithmetic. The main advantage of floating-point over fixed-point arithmetic is the wide dynamic range it introduces. Moreover, it avoids numerical issues such as scaling and overflow/underflow concerns at the expense of higher cost. Furthermore, floating-point implementation allows for an FFT co-processor to collaborate with general purpose processors. This offloads computationally intensive tasks from the primary processor. The first part of this thesis, which is devoted to FFT co-processors, proposes a new FFT architecture that uses a new Binary-Signed Digit (BSD) carry-limited adder, a new floating-point BSD multiplier and a new floating-point BSD three-operand adder. Finally, a new unit labeled as Fused-Dot-Product-Add (FDPA) is designed to compute AB+CD+E over floating-point BSD operands. The second part of the thesis discusses decimal arithmetic operations implemented in hardware using redundant number systems. These operations are popularly used in decimal floating-point co-processors. A new signed-digit decimal adder is proposed along with a sequential decimal multiplier that uses redundant number systems to increase the operational frequency of the multiplier. New redundant decimal division and square-root units are also proposed. The architectures proposed in this thesis were all implemented using Hardware-Description-Language (Verilog) and synthesized using Synopsys Design Compiler. The evaluation results prove the speed improvement of the new arithmetic units over previous pertinent works. Consequently, the FFT and decimal co-processors designed in this thesis work with at least 10% higher speed than that of previous works. These architectures are meant to fulfill the demand for the high-speed co-processors required in various applications such as multimedia services and financial computations.
83

Building in the styles of their time Fugman, Cramer and Uhlrich /

Barrett, Rebecca L. January 2008 (has links)
Thesis (M.A.)--Cleveland State University, 2008. / Abstract. Title from PDF t.p. (viewed on Mar. 27, 2009) Includes bibliographical references (p. 107-113) and appendix. Available online via the OhioLINK ETD Center. Also available in print.
84

Co-teaching/co-education in Greek secondary mainstream classrooms, from the perspective of co-teachers and children with special educational needs

Xanthopoulou, Pinelopi January 2017 (has links)
Co-teaching as an inclusive educational model is a new approach in Greece which aims to support the inclusion of children with special educational needs (SEN) in mainstream schools. This research aimed to investigate and evaluate co-teaching practices as well as teachers’ and students’ with SEN perceptions with regard to co-teaching. This research adopted a mixed methodology in two independent phases in order to address the needs of the study. Namely, 140 teachers were surveyed and multiple case studies of five different secondary co-taught classrooms were incorporated. This study showed that the way co-teaching is implemented in Greek secondary schools is closer to the model of “one teach-one assist”. Specifically, co-teachers saw the general teacher as responsible for all children, while the special teacher as responsible for an individual child with SEN included in a mainstream classroom. Thus, limited special teacher role expansion to all children was observed. The study showed that the general teachers were more negative about the sharing of various classroom responsibilities compared to the special teachers. Moreover, the approach of children’s withdrawal out of class was implemented to a significant extent. According to the research findings it was largely the special teachers who preferred this integrated approach and not the general teachers. Also, limited differentiation and grouping methods were used by co-teachers. In addition, this study indicated that co-teaching pairs did not collaborate with each other in an extensive way and did not commonly plan lessons together. Thus, teacher participants were quite sceptical in relation to the potential personal benefits of co-teaching to themselves. This study showed teacher training in co-teaching, teachers’ sensitivity and positive attitudes towards children with SEN, collaboration between co-teachers and mutual planning time, clear and official allocation of co-teaching roles and special teachers employment at the beginning of the academic year were all regarded as factors which would facilitate the successful implementation of co-teaching. Interestingly, the present study revealed that from the perspectives of both teachers and children with SEN the model of “one teach-one assist” seemed to have positive academic outcomes to children with SEN. However, the model of “one teach-one assist” seemed to have not only positive but also negative social and personal outcomes for children with SEN. From the perspective of some teachers and children with SEN respondents it seems that the model of “one teach-one assist” limited the social interactions of some children with SEN and interrelationships with the remaining children, which was due to sitting next to them during the lesson time and escorting them during the break time. Moreover, children with SEN did not see that co-teaching resulted in their social skills development. As a result some children with SEN expressed their unwillingness to be supported by a special teacher during the following academic year. Among the various disadvantages of co-teaching that children with SEN mentioned was the confusion that they usually felt when both teachers were speaking simultaneously. Lastly, children with SEN who experienced the out of class support expressed their preference for being supported out of the mainstream classroom. This was because they saw that the out of class support benefited them academically.
85

Co-infecção com Leishmania major e Trypanosoma brucei brucei controla a gravidade da patologia da leishmaniose cutânea

Pereira, Laís da Silva January 2015 (has links)
Submitted by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2016-02-04T15:52:03Z No. of bitstreams: 1 Lais da Silva Pereira Co-infecção...2015.pdf: 2458556 bytes, checksum: 23a6b27a228ed08f29d7e68206a6a31d (MD5) / Approved for entry into archive by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2016-02-04T15:52:14Z (GMT) No. of bitstreams: 1 Lais da Silva Pereira Co-infecção...2015.pdf: 2458556 bytes, checksum: 23a6b27a228ed08f29d7e68206a6a31d (MD5) / Made available in DSpace on 2016-02-04T15:52:14Z (GMT). No. of bitstreams: 1 Lais da Silva Pereira Co-infecção...2015.pdf: 2458556 bytes, checksum: 23a6b27a228ed08f29d7e68206a6a31d (MD5) Previous issue date: 2015 / Fundação Oswaldo Cruz, Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia, Faculdade de Medicina. Salvador, BA, Brasil / Os resultados das co-infecções nas leishmanioses cutânea (LC) são variáveis. Neste estudo, demonstramos o desfecho da co-infecção com Trypanosoma brucei brucei sobre a LC, causada por L. major. Infectamos camundongos C57BL/6 com T. b. brucei e estes foram tratados com o Berenil para controlar a infecção antes da transmissão da L. major por picadas de Lutzomyia longipalpis infectados. Nossos resultados revelam que, a infecção ativa com o T. b. brucei controla a patologia da LC causada por L. major. Comparados aos controles, camundongos coinfectados mostraram uma diminuição significativa do tamanho da lesão até 6 semanas após infecção. Adicionalmente, uma diminuição significativa da carga parasitária foi observada 3 semanas após a infecção. É importante salientar que a proteção observada não foi devido a reação cruzada entre os antígenos do T. b. brucei e L. major, mas por uma ativação não específica das células T efetoras, tanto sistemicamente como localmente no sítio da infecção, induzindo uma resposta inflamatória intensa, em particular com a produção de IFN-γ e em menor concentração de IL-10. Concluímos que a ativação das células T pelo curso da infecção com T. b. brucei, modulou a infecção com L. major, resultando em proteção. / The outcome of co-infections on cutaneous leishmaniasis (CL) is variable. Here, we determined the outcome of a co-infection with Trypanosoma brucei brucei on CL caused by L. major. We infected C57BL/6 mice with T. b. brucei and treated them with Berenil to control parasite growth prior to L. major transmission by infected Lutzomyia longipalpis bites. Our results revealed that an active infection with T. b. brucei controls the pathology of CL by L. major. Compared to controls, co-infected mice show a significant decrease in lesion size up to 6 weeks post-infection. Additionally, a significant decrease in the parasite load was observed at 3 weeks post-infection. Importantly, the observed protection was not due to cross-reactivity between antigens of T. b. brucei and L. major but to a non-specific activation of effector T cells, both at the site of infection and systemically, that induces a strong inflammatory response, in particular IFN-γ and at a lower IL-10 level. We conclude that activation of T cells by an ongoing T. b. brucei infection modulates the outcome of infection with L. major resulting in protection.
86

Co-Pirólise de resíduos de polietileno com gás-óleo da Bacia de Campos / Co-pirolysis of Bacia de Campos polyethylene waste

Débora da Silva Carneiro 31 May 2007 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / Nesse estudo foi realizado o processo de co-pirólise de resíduo de plástico de polietileno com gás-óleo com variação de temperatura. Primeiramente, as amostras de polietileno e gás-óleo foram submetidas a co-pirólise térmica em atmosfera inerte a 550C e depois foram avaliada a eficiência do processo a 500C e 450C. Os líquidos pirolíticos obtidos por este tratamento térmico foram caracterizados por cromatografia gasosa acoplada a espectrometria de massas (CG/EM) objetivando a avaliação do potencial energético destes líquidos. Os picos identificados no espectro de massas indicam a elevada geração de parafinas e olefinas, comprovando que o processo é promissor na utilização de resíduos plásticos na obtenção de óleos combustíveis que podem servir como insumos para a indústria petroquímica. / In this study the process of co-pyrolysis of plastic polyethylene residue was carried through with gas-oil under temperature variation. Initially the two samples had been submitted the thermal co-pyrolysis in inert atmosphere 550C, furtherly evaluated the efficiency of the process 500C and 450C. The pyrolysed liquids produced by this thermal treatment had been characterized by gaseous chromatography connected to the spectrometry of masses (CG/EM) objectifying the evaluation of the energy potential of these liquids. The peaks identified in the spectra of masses indicated the high paraffin generation and olefinas, proving that the process is promising in the use of plastic residues in the combustible oil attainment that can serve as feedstock for the petrochemical industry.
87

Desenvolvimento de novos sistemas de eletrocatalisadores nano-dispersos 20%Pt-(2% Pt-Ce0,9W0,102)/C tolerantes ao monóxido de carbono( CO) para ânodos de PEMFC / Development of new systems of nano-disperse 20%Pt-(2%Pt-Ce0,9W0,1O2)/C electrocatalysts tolerant to carbon monoxide (CO) for PEMFCs anodes

Júlio Nandenha 23 August 2011 (has links)
O material (pó) de nanofase de Ce0,9W0,1O2 foi sintetizado por coprecipitação de oxalatos de cério (IV) e cátions de tungstênio (IV). A redução da platina (2%) foi feita pelo método da redução por álcool, utilizando uma solução de ácido hexacloroplatínico (H2PtCl6.6H2O) como fonte do metal, óxido de cério dopado com tungstênio (Ce0,9W0,1O2) utilizado como suporte e, uma solução de etilenoglicol/água (75/25, v/v) como solvente e agente redutor. Os materiais 2%Pt-Ce0,9W0,1O2 foram misturados em Pt/C E-TEK 20%, utilizando-se processo de mistura física para produzir os eletrocatalisadores de 20%Pt-(2%Pt-Ce0,9W0,1O2)/C. Os eletrocatalisadores obtidos foram caracterizados por espectroscopia de energia dispersiva de raios X (EDX) acoplado à microscopia eletrônica de varredura (MEV), análises de difração de raios X (DRX), e microscopia eletrônica de transmissão (MET). O conjunto eletrodos-membrana (MEAs) foram preparados para o ânodo com cargas iguais a 0,401, 0,364, 0,328 mg Pt cm-2 de eletrocatalisadores 20%Pt-(2%Pt-Ce0,9W0,1O2)/C produzidos. No cátodo foi usada uma carga de 0,4 mg Pt cm-2 de eletrocatalisador Pt/C ETEK. A polarização anódica foi realizada para oxidação de H2/CO (100 ppm de CO). A tolerância ao CO foi estudada utilizando o processo eletroquímico (stripping de CO e medidas de curvas de polarização). Os resultados obtidos mostraram que a oxidação de CO adsorvido a CO2 na superfície de platina ocorre em potenciais menos positivos mostrando tolerância ao CO adsorvido nestes eletrocatalisadores (20%Pt-(2%Pt-Ce0,9W0,1O2)/C (50:50, 60:40 e 70:30)) a uma temperatura de 85 ºC e com pressão absoluta de 2 bar para ânodo e cátodo, comparado com Pt/C E-TEK 20%. / The nanophase material (powder) of Ce0,9W0,1O2 was synthesized via coprecipitation of oxalates of cerium (IV) and tungsten cations. The reduction of platinum (2%) was made by the method of alcohol reduction, using an acid solution hexachloroplatinic (H2PtCl6.6H2O) as metal source, cerium oxide doped with tungsten (Ce0,9W0,1O2) used as support and the solution of ethylene glycol/water (75/75, v/v) as solvent and reducing agent. The 2%Pt-Ce0,9W0,1O2 materials were mixed in Pt/C E-TEK 20% using physical mixing process to produce the 20%Pt-(2%Pt-Ce0,9W0,1O2)/C electrocatalyst. The materials were characterized by energy dispersive X-ray spectroscopy (EDX) coupled to scanning electron microscopy (SEM), X-ray difratometry analysis (XRD) and transmission electronic microscopy (TEM). The membrane electrodes assembly (MEAs) were prepared with loads equal to 0.401, 0.364, 0.328 mg Pt cm-2 for 20%Pt(2%Pt-Ce0,9W0,1O2)/C electrocatalysts produced. In the cathode a load of 0.4 mg Pt cm-2 of commercial Pt/C ETEK electrocatalyst was used. The anodic polarization was carried out for oxidation of the mixture H2/CO(100 ppm CO). The CO tolerance was studied using electrochemical process (CO stripping and measurements of polarization curves). The results showed that the oxidation of CO adsorbed to CO2 on the surface of platinum occur at less positive potentials showing tolerance to CO adsorbed on these 20%Pt-(2%Pt-Ce0,9W0,1O2)/C (50:50, 60:40 and 70:30) electrocatalysts at a temperature of 85 ºC and absolute pressure of 2 bar for anode and cathode, compared with Pt/C E-TEK 20%.
88

Co-Pirólise de resíduos de polietileno com gás-óleo da Bacia de Campos / Co-pirolysis of Bacia de Campos polyethylene waste

Débora da Silva Carneiro 31 May 2007 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / Nesse estudo foi realizado o processo de co-pirólise de resíduo de plástico de polietileno com gás-óleo com variação de temperatura. Primeiramente, as amostras de polietileno e gás-óleo foram submetidas a co-pirólise térmica em atmosfera inerte a 550C e depois foram avaliada a eficiência do processo a 500C e 450C. Os líquidos pirolíticos obtidos por este tratamento térmico foram caracterizados por cromatografia gasosa acoplada a espectrometria de massas (CG/EM) objetivando a avaliação do potencial energético destes líquidos. Os picos identificados no espectro de massas indicam a elevada geração de parafinas e olefinas, comprovando que o processo é promissor na utilização de resíduos plásticos na obtenção de óleos combustíveis que podem servir como insumos para a indústria petroquímica. / In this study the process of co-pyrolysis of plastic polyethylene residue was carried through with gas-oil under temperature variation. Initially the two samples had been submitted the thermal co-pyrolysis in inert atmosphere 550C, furtherly evaluated the efficiency of the process 500C and 450C. The pyrolysed liquids produced by this thermal treatment had been characterized by gaseous chromatography connected to the spectrometry of masses (CG/EM) objectifying the evaluation of the energy potential of these liquids. The peaks identified in the spectra of masses indicated the high paraffin generation and olefinas, proving that the process is promising in the use of plastic residues in the combustible oil attainment that can serve as feedstock for the petrochemical industry.
89

Co-pirólise de polipropileno pós-consumo com gasóleo / Co-pyrolysis of polypropylene residues with gas-oil

Luiz Carlos Fonte Nova de Assumpção 30 June 2008 (has links)
O presente trabalho buscou avaliar o processo de co-pirólise de resíduos de polipropileno com gasóleo, variando a temperatura e a quantidade de polipropileno no meio reacional. A co-pirólise é uma rota promissora, uma vez que minimiza o impacto ambiental causado pela disposição do plástico de maneira inadequada, evita seu acúmulo em lixões e permite um melhor aproveitamento de um recurso natural não-renovável, o petróleo, matéria-prima importante para a geração de energia e obtenção de produtos químicos. As amostras de polipropileno e gasóleo foram submetidas à co-pirólise térmica em atmosfera inerte, em sistema de leito fixo, sob fluxo constante de nitrogênio, variando a temperatura de 400C a 500C e a quantidade de PP no meio reacional de 0,1 a 1,0 g. A influência do gasóleo no meio foi avaliada pelos testes na ausência de PP. Os líquidos pirolíticos obtidos foram caracterizados por cromatografia gasosa modificada, com o objetivo de avaliar a geração de frações na faixa da destilação do diesel. De uma maneira geral, pôde-se observar que o aumento da quantidade de PP no meio reacional favorece a redução do rendimento de líquido pirolítico e o aumento da quantidade de sólido gerado, efeito inverso ao do aumento da temperatura. Com relação ao rendimento geral de produtos na faixa de destilação do diesel na co-pirólise, a adição de PP ao meio não interfere muito no resultado. Já o aumento de temperatura favorece o aumento do rendimento de produtos nessa faixa de destilação. Os resultados obtidos comprovam o potencial da co-pirólise como método de reciclagem química de artefatos de polipropileno pós-consumo / In this study, the process of co-pyrolysis of polypropylene (PP) residues with gas-oil was evaluated, varying the temperature and the amount of polypropylene fed to the reactor. The co-pyrolysis is a promising route to minimize the environmental impact caused by the inadequate disposal of plastics, preventing its accumulation in landfields and giving a better use of the non renewable raw material (oil). The polypropylene samples and gas-oil were submitted to the thermal co-pyrolysis in an inert atmosphere, varying the temperature from 400C to 500C and the amount of PP from 0,1 to 1,0g. The influence of the gas-oil was evaluated carrying the co-pyrolysis in the absence of PP. The pyrolysed liquids produced by this thermal treatment were characterized by modified gaseous chromatography in order to evaluate the yield in the range of distillation of diesel. As a result, the increase of PP amount lead to a reduction in the yield of the pyrolytic liquid and to an increase of the amount of solid generated. The effect of temperature increase showed an inverse result. The addition of PP in the reactor showed little influence in the yield of diesel in the co-pyrolysis. On the other hand, an increase in temperature favors the increase of products in this range of destillation. The results show that plastic residue co-pyrolysys is a potential method for chemical recycling of plastic products
90

Estudos estruturais da SEPT8 e análise de suas interações com SEPT5 e SEPT7 / Structural studies of SEPT8 and analysis of its interaction with SEPT5 and SEPT7

Sinara Teixeira do Brasil Morais 29 May 2014 (has links)
Septinas são proteínas que ligam GTP e interagem entre si formando heterocomplexos, os quais formam filamentos e estruturas de maior nível de organização. Tais filamentos, além de se mostrarem importantes durante a citocinese também podem estar envolvidos em outros processos celulares tais como determinação da polaridade celular e reorganização do citoesqueleto. As septinas, inicialmente descobertas em Saccharomyces cerevisiae, já foram identificadas também em fungos, algas-verdes, mamíferos, porém nunca em plantas. Tipicamente, septinas apresentam três domínios estruturais compostos por um domínio central de ligação ao GTP flanqueado por um N-terminal variável e um C-terminal que pode conter sequências do tipo coiled-coil. Este trabalho teve como objetivo a caracterização do domínio de ligação a GTP da septina 8 humana (SEPT8G) por meio de estudos biofísicos. Nesse sentido, SEPT8G foi eficientemente produzida em E. coli, tendo seu estado dimérico em solução confirmado por cromatografia de exclusão molecular. Diferentemente das outras septinas já reportadas, mesmo dimérica a SEPT8G apresentou-se na forma apo. Ensaios de atividade GTPásica foram realizados, confirmando a incapacidade dessa septina em hidrolisar o GTP. Ainda, análises de estabilidade térmica por Dicroísmo Circular revelaram que a presença do íon magnésio leva à diminuição de sua estabilidade estrutural. Baseando-se em resultados prévios de interação obtidos pela técnica do duplo-híbrido em leveduras, estudos voltados à análise da interação entre as septinas 7 e 8 e, posteriormente, entre as septinas 5, 7 e 8 foram realizados. A co-purificação do complexo formado pelas septinas 7 e 8 mostrou-se dependente da região C-terminal completa de SEPT7 de modo que, quando ausente, a interação mostrou-se expressivamente prejudicada. Já o complexo formado pelas septinas 5/7/8 foi obtido contendo as três proteínas em frações equimolares e solúveis, disponibilizando assim um novo heterocomplexo de septinas para ensaios funcionais e estruturais. / Septins are GTP-binding proteins that interact with each other to form heterocomplexes, which form filaments and higher order structures. These filaments are important for cytokinesis and may be involved in other cellular processes such as the determination of cell polarity and cytoskeleton reorganization. The septins, initially discovered in Saccharomyces cerevisiae, have also been identified in fungi, green algae, mammals but not in plants. Typically, septins have three structural domains comprising a central GTP binding domain flanked by a variable N-terminal and a C-terminal which can contain coiled-coil structures. This work sought to characterize the GTP-binding domain of the human septin 8 (SEPT8G) through biophysical studies. Accordingly, SEPT8G was efficiently produced in E. coli, and its dimeric state in solution was confirmed by size exclusion chromatography. Compared to other septins previously reported, the dimeric SEPT8G presented itself as an apo-protein. GTPase activity assays were performed, confirming the inability of this septin to hidrolyse GTP. Additionally, thermal stability analyses by Circular Dichroism showed that the presence of the magnesium ion leads to a decrease of structural stability. Considering previous results of septins interactions from yeast two-hybrid experiments, we have analyzed the interaction between the septins 7, 8 and subsequently among septins 5, 7 and 8. Co-purification of the complex formed by the septins 7 and 8 showed to be dependent on the complete SEPT7 C-terminal region so that, when absent, the interaction was significantly impaired. The obtained complex formed by septins 5/7/8 contained the three proteins in soluble and equimolar fractions, providing a new septin heterocomplex for functional and structural studies.

Page generated in 0.0313 seconds