953 resultados para Research formation multireferential
Resumo:
The following paper is based on the author's two-year research and fieldwork in Iran and examines the process of political and social changes since the Iranian Revolution of 1979 and the subsequent impact of the Iran-Iraq War of 1980-88. This paper focuses on the transition of traditional, small villages into rusta-shahr or small rural cities and the first and second nation-wide elections of shoura or councils which were the first steps toward self-government. The author is guardedly optimistic regarding this democratic process but warns of possible future social unrest if changes are not more "balanced" between cities and rural areas and if the employment needs of the burgeoning younger generation are not met, political and social consequences may be catastrophic.
Resumo:
This paper shows descriptively how the knowledge network in East Asia has been formed. In addition, the correlation between the knowledge network and economic growth is also examined. Evidence is provided to show that plugging into the knowledge network of developed countries could be a key for increasing innovativeness in a country.
Resumo:
We investigated the atomic surface properties of differently prepared silicon and germanium (100) surfaces during metal-organic vapour phase epitaxy/chemical vapour deposition (MOVPE/MOCVD), in particular the impact of the MOVPE ambient, and applied reflectance anisotropy/difference spectroscopy (RAS/RDS) in our MOVPE reactor to in-situ watch and control the preparation on the atomic length scale for subsequent III-V-nucleation. The technological interest in the predominant opto-electronic properties of III-V-compounds drives the research for their heteroepitaxial integration on more abundant and cheaper standard substrates such as Si(100) or Ge(100). In these cases, a general task must be accomplished successfully, i.e. the growth of polar materials on non-polar substrates and, beyond that, very specific variations such as the individual interface formation and the atomic step structure, have to be controlled. Above all, the method of choice to grow industrial relevant high-performance device structures is MOVPE, not normally compatible with surface and interface sensitive characterization tools, which are commonly based on ultrahigh vacuum (UHV) ambients. A dedicated sample transfer system from MOVPE environment to UHV enabled us to benchmark the optical in-situ spectra with results from various surfaces science instruments without considering disruptive contaminants. X-ray photoelectron spectroscopy (XPS) provided direct observation of different terminations such as arsenic and phosphorous and verified oxide removal under various specific process parameters. Absorption lines in Fourier-transform infrared (FTIR) spectra were used to identify specific stretch modes of coupled hydrides and the polarization dependence of the anti-symmetric stretch modes distinguished different dimer orientations. Scanning tunnelling microscopy (STM) studied the atomic arrangement of dimers and steps and tip-induced H-desorption proved the saturation of dangling bonds after preparati- n. In-situ RAS was employed to display details transiently such as the presence of H on the surface at lower temperatures (T <; 800°C) and the absence of Si-H bonds at elevated annealing temperature and also surface terminations. Ge buffer growth by the use of GeH4 enables the preparation of smooth surfaces and leads to a more pronounced amplitude of the features in the spectra which indicates improvements of the surface quality.
Resumo:
A research programme is being carried out at the Institute Nacional de Tecnica Aeroespacial of Spain, on several aspects of the formation of nitrogen oxides in continuous flow combustion systems, considering hydrogen and hydrocarbons as fuels. The research programme is fundamentally oriented on the basic aspects of the problem, although it also includes the study of the influence on the formation process of several operational and design variables of the combusters, such as type of fuels, fuel/air ratio, degree of mixing in premixed type flames, existence of droplets as compared with homogeneous combustion.This problem of nitrogen oxides formation is receiving lately great attention, specially in connection with automobile reciprocating engines and aircraft gas turbines. This is due to the fact of the increasing frequency and intensity of photochemical hazes or smog, typical of urban areas submitted to strong solar radiation, which are originated by the action on organic compounds of the oxidants resulting from the photochemical decomposition of nitrogen dioxide N02. In the combustion process almost all nitrogen oxides are in form of NO. This nitric oxide reacts with the oxygen of the air and forms N02, this reaction only taking place in or near the exhaust of tne motors, since the N0-02 reaction becomes frozen for the concentration existing in the atmosphere.
Resumo:
In this contribution, results of a theoretical study on different reactions that odine oxides, in the presence of water, can undergo to form iodine oxides particles in the atmosphere. Thermodynamic and kinetic properties of these reactions have been obtained at high level ab initio correlated calculations.
Resumo:
Ca-amendments are routinely applied to improve acid soils, whilst no-tillage (NT) has been widely recommended in soils where traditional tillage (TT) has led to losses of organic matter. However, the potential interactions between the two treatments are only partially known. Our study was conducted on an annual forage crop agrosystem with a degraded Palexerult soil located in SW Spain, in order to assess if the combination of NT plus a Ca-amendment provides additional benefits to those of their separate use. To this end we analysed the effects of four different combinations of tillage and Ca-amendment on selected key soil properties, focusing on their relationships. The experimental design was a split-plot with four replicates. The main factor was tillage (NT versus TT) and the second factor was the application or not of a Ca-amendment, consisting of a mixture of sugar foam (SF) and red gypsum (RG). Soil samples were collected from 3 soil layers down to 50 cm after four years of treatment (2009). The use of the Ca-amendment improved pH and Al-toxicity down to 25 cm and increased exchangeable Ca2+ down to 50 cm, even under NT due to the combined effect of SF and RG. Both NT and the Ca-amendment had a beneficial effect on total organic carbon (TOC), especially on particulate organic carbon (POC), in the 0–5 cm layer, with the highest contents observed when both practices were combined. Unlike NT, the Ca-amendment failed to improve soil aggregation in spite of the carbon supplied. This carbon was not protected within the stable aggregates in the medium term, making it more susceptible to mineralization. We suggest that the fraction of Al extracted by oxalate from solid phase (AlOxa-Cu-K) and the glomalin-related soil proteins (GRSPs) are involved in the accumulation of carbon within water stable aggregates, probably through the formation of non-toxic stable Al-OM compounds, including those formed with GRSPs. NT alone decreased AlK in the 0–5 cm soil layer, possibly by increasing POC, TOC and GRSPs, which were observed to play a role in reducing Al toxicity. From our findings, the combination of NT and Ca-amendment appears to be the best management practice to improve chemical and physical characteristics of acid soils degraded by tillage.
Resumo:
The phosphosilicate glass (PSG), fabricated by tube furnace diffusion using a POCl3 source, is widely used as a dopant source in the manufacturing of crystalline silicon solar cells. Although it has been a widely addressed research topic for a long time, there is still lack of a comprehensive understanding of aspects such as the growth, the chemical composition, possible phosphorus depletion, the resulting in-diffused phosphorus profiles, the gettering behavior in silicon, and finally the metal-contact formation. This paper addresses these different aspects simultaneously to further optimize process conditions for photovoltaic applications. To do so, a wide range of experimental data is used and combined with device and process simulations, leading to a more comprehensive interpretation. The results show that slight changes in the PSG process conditions can produce high-quality emitters. It is predicted that PSG processes at 860 °C for 60 min in combination with an etch-back and laser doping from PSG layer results in high-quality emitters with a peak dopant density Npeak = 8.0 × 1018 cm−3 and a junction depth dj = 0.4 μm, resulting in a sheet resistivityρsh = 380 Ω/sq and a saturation current-density J0 below 10 fA/cm2. With these properties, the POCl3 process can compete with ion implantation or doped oxide approaches.
Resumo:
O estudo pretende debater a idéia de sujeito a partir do cruzamento das idéias de autonomia, autoria e autor-cidadão como eixo teórico para, a partir da abordagem multirreferencial, indagar sobre de que maneiras é possível contribuir para a formação de sujeitos autônomos considerando a prática em uma universidade privada confessional. O sujeito aqui é apresentado não na perspectiva de um corpo biológico e físico, mas como projeto, considerando a historicidade, sociabilidade e, também, a questão da psique do ser humano. O objetivo do trabalho é analisar a formação do sujeito tendo em vista a proposta pedagógica da UMESP UNIVERSIDADE METODISTA DE SÃO PAULO. Esta opção justifica-se essencialmente pelo fato da escola apresentar uma proposta educacional diferenciada, que visa a formação cidadã. Os conceitos de instituição e autonomia são de extrema relevância para analisar no contexto da pesquisa proposta as representações e as práticas legítimas, bem como a necessidade de ressignificação da idéia de cidadania, diante das exigências da vida contemporânea. Trata-se, portanto, de uma pesquisa qualitativa de cunho exploratório. Quanto aos procedimentos metodológicos foi realizada a observação participante e com a aplicação de um roteiro qualificado buscou-se ouvir alunos da comunidade acadêmica. Foi possível perceber claramente as intenções ligadas à confessionalidade retratadas no Projeto Pedagógico da UMESP. Quanto às intenções dos alunos, observou-se a preocupação com a formação profissional. Tendo em vista nosso entendimento a respeito do exercício da cidadania a partir da autonomia do sujeito, estendemos nosso olhar para todos os atores sociais envolvidos. Observamos que é possível realizar um trabalho em direção ao autorcidadão porque o aluno, em geral, está aberto a transformar-se. A questão é relacional. Tem a ver de fato com a maneira como o ensino acontece. Professores e alunos devem encontrar-se como sujeitos em permanente construção, implicados. A educação pode desenvolver pessoas críticas e autônomas, sujeitos autores de suas próprias vidas atuando de acordo com seus desejos e conscientes de suas reais necessidades e responsabilidades.(AU)
Resumo:
O estudo pretende debater a idéia de sujeito a partir do cruzamento das idéias de autonomia, autoria e autor-cidadão como eixo teórico para, a partir da abordagem multirreferencial, indagar sobre de que maneiras é possível contribuir para a formação de sujeitos autônomos considerando a prática em uma universidade privada confessional. O sujeito aqui é apresentado não na perspectiva de um corpo biológico e físico, mas como projeto, considerando a historicidade, sociabilidade e, também, a questão da psique do ser humano. O objetivo do trabalho é analisar a formação do sujeito tendo em vista a proposta pedagógica da UMESP UNIVERSIDADE METODISTA DE SÃO PAULO. Esta opção justifica-se essencialmente pelo fato da escola apresentar uma proposta educacional diferenciada, que visa a formação cidadã. Os conceitos de instituição e autonomia são de extrema relevância para analisar no contexto da pesquisa proposta as representações e as práticas legítimas, bem como a necessidade de ressignificação da idéia de cidadania, diante das exigências da vida contemporânea. Trata-se, portanto, de uma pesquisa qualitativa de cunho exploratório. Quanto aos procedimentos metodológicos foi realizada a observação participante e com a aplicação de um roteiro qualificado buscou-se ouvir alunos da comunidade acadêmica. Foi possível perceber claramente as intenções ligadas à confessionalidade retratadas no Projeto Pedagógico da UMESP. Quanto às intenções dos alunos, observou-se a preocupação com a formação profissional. Tendo em vista nosso entendimento a respeito do exercício da cidadania a partir da autonomia do sujeito, estendemos nosso olhar para todos os atores sociais envolvidos. Observamos que é possível realizar um trabalho em direção ao autorcidadão porque o aluno, em geral, está aberto a transformar-se. A questão é relacional. Tem a ver de fato com a maneira como o ensino acontece. Professores e alunos devem encontrar-se como sujeitos em permanente construção, implicados. A educação pode desenvolver pessoas críticas e autônomas, sujeitos autores de suas próprias vidas atuando de acordo com seus desejos e conscientes de suas reais necessidades e responsabilidades.(AU)
Quantification of a distributive fluvial system; the Salt Wash DFS of the Morrison Formation, SW USA
Resumo:
Peer reviewed
Resumo:
We analyzed the pathogenesis-related generation of H2O2 using the microscopic detection of 3,3-diaminobenzidine polymerization in near-isogenic barley (Hordeum vulgare L.) lines carrying different powdery mildew (Blumeria graminis f.sp. hordei) resistance genes, and in a line expressing chemically activated resistance after treatment with 2,6-dichloroisonicotinic acid (DCINA). Hypersensitive cell death in Mla12 and Mlg genotypes or after chemical activation by DCINA was associated with H2O2 accumulation throughout attacked cells. Formation of cell wall appositions (papillae) mediated in Mlg and mlo5 genotypes and in DCINA-activated plants was paralleled by H2O2 accumulation in effective papillae and in cytosolic vesicles of up to 2 μm in diameter near the papillae. H2O2 was not detected in ineffective papillae of cells that had been successfully penetrated by the fungus. These findings support the hypothesis that H2O2 may play a substantial role in plant defense against the powdery mildew fungus. We did not detect any accumulation of salicylic acid in primary leaves after inoculation of the different barley genotypes, indicating that these defense responses neither relied on nor provoked salicylic acid accumulation in barley.
Resumo:
Long-day exposure of the grass Lolium temulentum may regulate flowering via changes in gibberellin (GA) levels. Therefore, we have examined both GA levels and expression of a MYB transcription factor that is specific to the GA signal transduction pathway in monocots. This MYB gene from L. temulentum shows over 90% nucleotide identity with the barley and rice GAMYB genes, and, like them, gibberellic acid (GA3) up-regulates its expression in the seed. Furthermore, cDNAs of both the barley and L. temulentum GAMYB show the same simple patterns of hybridization with digests of L. temulentum genomic DNA. Compared with vegetative shoot apices of L. temulentum, the in situ mRNA expression of LtGAMYB does not change during the earliest steps of “floral” initiation at the apex. However, by 100 h (the double-ridge stage of flowering) its expression increased substantially and was highest in the terminal and lateral spikelet sites. Thereafter, expression declined overall but then increased within stamen primordia. Prior to increased LtGAMYB expression, long-day exposure sufficient to induce flowering led to increased (5- to 20-fold) levels of GA1 and GA4 in the leaf. Thus, increases first in GA level in the leaf followed by increased expression of LtGAMYB in the apex suggest important signaling and/or response roles in flowering.
Resumo:
Parasitic plants in the Scrophulariaceae develop infective root structures called haustoria in response to chemical signals released from host-plant roots. This study used a simple in vitro assay to characterize natural and synthetic molecules that induce haustoria in the facultative parasite Triphysaria versicolor. Several phenolic acids, flavonoids, and the quinone 2,6-dimethoxy-p-benzoquinone induced haustoria in T. versicolor root tips within hours after treatment. The concentration at which different molecules were active varied widely, the most active being 2,6-dimethoxy-p-benzoquinone and the anthocyanidin peonidin. Maize (Zea mays) seeds are rich sources of molecules that induce T. versicolor haustoria in vitro, and chromatographic analyses indicated that the active molecules present in maize-seed rinses include anthocyanins, other flavonoids, and simple phenolics. The presence of different classes of inducing molecules in seed rinses was substantiated by the observation that maize kernels deficient in chalcone synthase, a key enzyme in flavonoid biosynthesis, released haustoria-inducing molecules, although at reduced levels compared with wild-type kernels. We discuss these results in light of existing models for host perception in the related parasitic plant Striga.