Determination of polyamines in organic extracts from roots of Canavalia ensiformis by capillary electrophoresis

A rapid, selective and specific capillary zone electrophoresis method to determine polyamines in organic extracts from roots of Canavalia ensiformis (Jack Beans) was developed using ultra violet (UV) detection. Canavalia ensiformis is relatively free from diseases and it is used as reference in allelopathy studies. Polyamines are widely distributed in plant and it could be involved in plant pathogen interactions. Optimal separation was achieved using 15 mmol.L-1formic acid (pH 3.0) + 4 mmol.L-1 imidazole as a background electrolyte. It was possible to identify and quantify the polyamines on herbal samples in the presence of other phytochemical substances and analyze them quickly (up to 6 min). The applicability of this method was evaluated in crude organic extracts from roots of Canavalia ensiformis.

Vad ska elever lära sig angående naturvetenskaplig verksamhet? : En analys av svenska läroplaner för grundskolan under 50 år

The purpose of this study is to contribute to an understanding of which changes related to scientific inquiry have been made historically in curriculum documents. A comparative analysis is made of five Swedish national curricula– Lgr 62, Lgr 69, Lgr 80, Lpo 94 and Lgr 11 – during the last 50 years regarding what compulsory school students (school years 1–9) should learn about scientific inquiry. It focuses 1) what students should learn about carrying out scientific inquiries, and 2) what students should learn about the nature of science. All of the curricula examined have aims concerning scientific inquiry. The results show that during the period there have been many shifts in emphasis and changes of aims, for example from learning an inductive method to a more deductive one, and from an emphasis on carrying out investigations to an emphasis on more conceptual understanding of scientific investigations. Because teaching traditions tend to conserve aspects of earlier curricula, it is discussed how the results can help teachers, teacher students and curriculum developers to better see the consequences of the changes for teaching and learning.

Performance Analysis of a Semantics Enabled Service Registry

Service discovery is a critical task in service-oriented architectures such as the Grid and Web Services. In this paper, we study a semantics enabled service registry, GRIMOIRES, from a performance perspective. GRIMOIRES is designed to be the registry for myGrid and the OMII software distribution. We study the scalability of GRIMOIRES against the amount of information that has been published into it. The methodology we use and the data we present are helpful for researchers to understand the performance characteristics of the registry and, more generally, of semantics enabled service discovery. Based on this experimentation, we claim that GRIMOIRES is an efficient semantics-aware service discovery engine.

PReServ: Provenance Recording for Services

The importance of understanding the process by which a result was generated in an experiment is fundamental to science. Without such information, other scientists cannot replicate, validate, or duplicate an experiment. We define provenance as the process that led to a result. With large scale in-silico experiments, it becomes increasingly difficult for scientists to record process documentation that can be used to retrieve the provenance of a result. Provenance Recording for Services (PReServ) is a software package that allows developers to integrate process documentation recording into their applications. PReServ has been used by several applications and its performance has been benchmarked.

A security architecture for a semantic Grid registry

Existing registry technologies such as UDDI can be enhanced to support capabilities for semantic reasoning and inquiry, which subsequently increases its usability range. The Grimoires registry was developed to provide such support through the use of metadata attachments to registry entities. The use of such attachments provides a way for allowing service operators to specify security assertions pertaining to registry entities owned by them. These assertions may however have to be reconciled with existing registry policies. A security architecture based on the XACML standard and deployed in the OMII framework is outlined to demonstrate how this goal is achieved in the registry.

Abordagem histórica e perspectivas atuais do ensino superior agrícola no Brasil : uma investigação na UFRGS e na UC Davis

Este estudo analisa o Ensino Superior Agrícola Brasileiro – ESAB, como “campo” (Bourdieu, 1983a), diante do cenário do mundo cambiante em que vivemos, com os seguintes objetivos: (i) resgatar parte da história, destacando dois momentos de inflexão vividos pelo ESAB: o primeiro a partir da década de 1960, quando, dentro do projeto urbano-industrialista, foram lançadas as bases do conhecimento e das estruturas acadêmicas (ainda hegemônicos) para a “modernização da agricultura”. O segundo na virada do Século XX, quando existe uma multiplicidade de propostas e não há mais um modelo a ser copiado; (ii) sugerir alguns dos caminhos possíveis e suas implicações para as instituições do ESAB, que pretendam encontrar novo sentido social no seu trabalho; (iii) analisar a influência das Universidades Norte-americanas no ESAB, tendo em vista sua importância no período de 60 e como essa influência se manifesta no segundo momento. Um “college” norte-americano (College of Agricultural and Environmental Science da University of California – Davis) e uma faculdade brasileira (Faculdade de Agronomia da UFRGS) foram escolhidos, como centros de formação e de pesquisa importantes e com participação destacada nos intercâmbios bilaterais. Essas instituições servem como testemunhas exemplares da dinâmica geral. Em ambas foram realizadas investigações e foram ouvidos atores destacados (professores-pesquisadores), através de questionários e entrevistas ao vivo Nas duas universidades os professores mostraram-se conscientes sobre as mudanças em curso, mas na UFRGS parece que o debate está menos desenvolvido. Diante das tendências que se apresentam, a Agricultura Sustentável e a Biotecnologia foram eleitas como pólos aglutinadores de diferentes projetos em disputa no início do Milênio. O estudo conclui que ou as escolas de agronomia se modificam ou não se justificam e também que, as mudanças podem ou não se vincular à busca de uma ruptura paradigmática (Santos, 1997). Conclui ainda, que seria importante cada instituição explicitar sua proposta, mesmo que esta seja de convivência entre os diferentes projetos. Finalmente opina que, Agricultura Sustentável parece ser estrategicamente mais interessante; tendo em vista ser mais adequada à realidade social e ambiental do Brasil.

Teoria científica das empresas e participações societárias estatais - TEPSES: governanças pública, corporativa e o caso do Brasil

RESUMO Ao identificar a existência de lacuna teórica, o presente trabalho definiu como seu objetivo: Estabelecer os alicerces de uma epistéme sobre o fenômeno por meio do desenvolvimento de um arcabouço capaz de a) direcionar e dar sustentação à construção e ao desenvolvimento coletivo de uma Teoria Científica das Empresas e Participações Societárias Estatais – TEPSES, e de b) identificar elementos que viabilizem o desenvolvimento de respostas à questão aplicada central: Como devem os governos definir as missões, os critérios de desempenho e os mecanismos de governança das empresas estatais em um ambiente em mudança? Considerando sua materialidade, a relevância estratégica dessas empresas para os Estados contemporâneos, suas implicações para os processos de globalização e a administração uma ciência aplicada a demandarem nível de análise societal e abordagem multiparadigmática, o arcabouço e seus elementos proporcionaram resposta a várias inquietações e problemas expressos, alguns por mais de meio século, por autoridades no campo como Pritchett, Seidman, Sherwood, Shepherd, Aharoni, Millward, Hinds e Baumol. Oferecendo por redução fenomenológica uma definição de conceito universal para as empresas estatais e introduzindo, inter allia, os conceitos de capacidade essencial de Estado em seu intervalo – CEEi e de estatal patrimonial, que permitiram a construção de uma escala de interesses públicos; o arcabouço teórico focado rueschemeyeriano da TEPSES, constrói pontes entre os hemisférios da grande dicotomia do direito e entre aspectos de governanças pública e corporativa, por meio de tipologias lazarsfeldianas. Em suas seis dimensões iniciais e trinta e três relações o arcabouço foi aplicado por sondagem plausibilística ao caso das estatais diretas brasileiras, apresentando elevado grau de plausibilidade e qualidade, inclusive segundo critérios de Wacker. As formulações e explicitações da TEPSES oferecem respostas e possibilidades de tratamento a várias questões científicas mais amplas como: o paradoxo do conhecimento na regulação de Balleisen, a armadilha de Schneider, a dúvida de Ikeda/Mises e a reabertura da questão de adequação organizacional pelo nobel Simon; proporcionando ainda extensões a: tipologia de estruturas de governança do nobel Williamson, as concepções de sociedade prismática de Riggs, a definição da administração como ciência aplicada do nobel Simon, as formulações institucionalistas de Acemoglu e Robinson e as abordagens sobre intervenção de Estado do nobel Stiglitz. O arcabouço da TEPSES possibilita: a) a cada país, construir sua própria tipologia empírica de empresas estatais e assim geri-las a partir de respostas customizadas à questão aplicada central, analisar sua adequação como instrumento de políticas públicas e desenvolver critérios para suas privatizações; b) a gestores, pesquisadores e estudiosos de caso situar e analisar suas empresas a partir do arcabouço; c) às pesquisas pretéritas, terem seus dados reinterpretados à luz de um novo referencial e d) a todos, a possibilidade de conectarem seus trabalhos à epistéme da qual a TEPSES é alicerce e repositório. Conclui-se que o grau de relevância, em nível global, do fenômeno é na realidade muito superior à sua materialidade e ao grau de relevância atribuído inicialmente, devido à identificação de sua condição como fator empírico de capacidades de Estado, uma vez que à ausência e deficiências dessas capacidades são atribuídos colapsos e débâcles de vários Estados nacionais, que resultaram em elevadíssimos e incalculáveis custos humanos.

Weed interference on maize (Zea mays) under no tillage system

A field trial was carried out in Brazil in March 2002 with the aim to evaluate the effects of different timing and extension of weedy period on maize productivity. The hybrid Pioneer 30K75 was sowed under 7 t ha(-1) mulching promoted by glyphosate spraying. The treatments were divided in two groups: In the first group, weeds were maintained since the maize sowing until different periods in the crop cycle: 0, 14, 28, 42, 56, 70, and 150 days (harvesting time). In the second group, the maize crop was kept weed free for the same periods of the first group. Weed control was done through hand hoeing. A complete randomized blocks experimental design with five replications was used for plots distribution in the field. Nonlinear regression model was used to study the effects of weedy or weedfree periods on maize productivity. Weed community included 13 families and 31 species. Asteraceae, Poaceae, and Euphorbiaceae were the most abundant families. Results showed that under no tillage condition with 7 t ha-1 mulching at sowing time, the maize crop could cohabit with weed community for 54 days without any yield lost. on the other hand, if the crop was kept weed free for 27 days, the weed interference was not enable to reduce maize production. According to these results one weed control measure between 27 and 54 days after crop emergence could be enough to avoid any reduction in maize productivity.

Effects of plant densities and management of purple nutsedge on sugarcane yield and effect of growth stages and main way of herbicides contact and absorption on the control of tubers

Field experiments carried out with Cyperus rotundus L. at low (58-246), medium (318773), and high (675-1198 shoots/m(2)) densities showed sugarcane yield reductions of 13.5, 29.3, and 45.2%, respectively in relation to the control. In the second field experiment, the integration of a mechanic method with two sequences of plowing and disking operations in the dry season, and complementary applications of trifloxysulfuron-sodium + ametrine and sulfentrazone (rainy season) was studied. Average of the chain connected to original shoot showed 92, 95, and 65% of reduction with trifloxysulfuron-sodium + ametrine and surfactant, at the application stages early, preflowering, and full flowering, respectively.

Selectivity of the herbicide flazasulfuron applied after postemergence in sugarcane (Saccharum spp. L.) crop

The selectivity of the herbicide flazasulfaron was evaluated when applied at two rates (50 and 100 g/ha) with and without surfactants (Aterbane or Agral at 0.2% v/v). The treatment was applied at early (three leaves) and late (five to six leaves) stages of the postemergence of sugarcane plants (var. RB845257) grown in two soils (sandy and clay) with good moisture status before and after application. Despite the toxicity symptoms, especially at the late stage with the higher rate of application in the sandy soil, the herbicide did not affect the growth nor the stalk yield. The presence of the surfactants had no effect on the toxicity symptoms.

Detached leaf culture: Viability to evaluate 2,4-D toxicity symptoms in cotton apex leaves

To study the viability of detached leaf culture technique, studies were carried out with detached leaves from cotton apex (true trilobed leaves). The prepared leaves were sprayed with 2,4-D amine and ester, at rates of 10, 30, 70, and 100% of the recommended doses. Detached leaves without herbicide spray were used as controls. Simultaneously, a greenhouse experiment was conducted with the same treatments as used for the detached leaves experiment. Toxicity was measured through a 0-to-5 grading according to the percentage of affected leaf area in the detached leaves experiment or examining the affected rate of whole plant as indicated in the greenhouse. Results showed that the ester form of the herbicide induced earlier and more severe toxicity symptoms in detached leaves and greenhouse grown plants. Positive and significant correlations (p < 0.001) were found between toxicity results obtained at 7 and 14 days after application in detached leaves and greenhouse plants (r = 0.97 and 0.92, respectively). Negative, significant correlations (p < 0.005) were found between the toxicity levels found at 7 and 14 days after application in detached leaves and dry matter of cotton plants grown in the greenhouse (r = -0.92 and -0.92, respectively).