2,566 research outputs found
Strategies of buenos aires waiters to enhance memory capacity in a real-life setting
Human learning and memory evaluation in real-life situations remains difficult due to uncontrolled variables. Buenos Aires waiters, who memorize all the orders without written support, were evaluated in situ. Waiters received either eight different orders and customers remained seated in their original locations (OL), or changed locations (CL). Match between orders, subjects and location was decreased only in CL. Waiters' feature/location strategy links client with position at the table and beverage later. The hypothesis we raise is that memory-schemas link working memory to long-term memory networks through rapid encoding, making the information resistant to interference and enabling its fast retrieval if necessary cues are present
Revisiting the nonequilibrium phase transition of the triplet-creation model
The nonequilibrium phase transition in the triplet-creation model is
investigated using critical spreading and the conservative diffusive contact
process. The results support the claim that at high enough diffusion the phase
transition becomes discontinuous. As the diffusion probability increases the
critical exponents change continuously from the ordinary directed percolation
(DP) class to the compact directed percolation (CDP). The fractal dimension of
the critical cluster, however, switches abruptly between those two universality
classes. Strong crossover effects in both methods make it difficult, if not
impossible, to establish the exact location of the tricritical point.Comment: 7 pages, 12 figure
Learning as ecosystems:Shifting paradigms for more holistic programming in education and displacement
Meeting the educational needs and aspirations of learners affected by conflict and crisis, and particularly those who have been displaced within and across national borders is a wicked and vexing problem impeding progress on SDG4. We argue a radically different approach is required. Based on insights from complexity science and regenerative development, we present an ecosystem approach based on three dimensions: 1) connectedness and nestedness, 2) reflective learning and 3) working from potential rather than problems. We provide an example of where such work is already being explored, and the possibilities it offers for shifting paradigms informing programming and design of education for learners in displacement
Germination of spores and gametophytes of "Polystichum montevidense" (Spreng.) Rosenst. ("Dryopteridaceae")
Se presentan características sobre la germinación de las esporas, el desarrollo gametofítico y la estructura de los gametofitos adultos de Polystichum montevidense (Spreng.) Rosenst. obtenidos mediante cultivos estériles. Se encuentra que los esporangios originan 32 esporas monoletes con perisporio crestado. La germinación es de tipo Vittaria y se produce a los tres días después de la siembra. El desarrollo de los gametofitos corresponde al tipo Aspidium. Los gametofitos laminares producen un solo tipo de tricomas glandulares con secreción de naturaleza lipídica, distribuidos sobre el margen de la lámina y unos pocos sobre la superficie. Se cita por primera vez la presencia de gotas de aceite en las células de los gametofitos adultos. La expresión sexual se manifiesta en gametofitos de más de 100 días de edad, originándose solamente gametofitos femeninos. Se ilustra con fotografías obtenidas con microscopios de luz y microscopio electrónico de barrido.A description is made of characteristics of the germination of spores, gametophytic development and adult gametophyte structure of Polystichum montevidense (Spreng.) Rosenst. obtained by sterile culture. It was found that sporangia produce 32 monolete spores with crested perispore. The germination of Vittaria-type spores occurs three days after sowing. Gametophyte development is of the Aspidium type. The laminar gametophytes have only one type of glandular trichomes, with secretion of trichomes has a lipid nature, distributed on the edge of the lamina and a few on the surface. It is reported for the first time that adult gametophyte cells have oil droplets. Sexual expression is manifested in gametophytes of more than 100 days old, with only female gametophytes. All this is illustrated with pictures recorded with light microscopes and a scanning electron microscope
Análise de metilxantinas em dezesseis progênies de erva mate extraídas por dióxido de carbono supercrítico.
A Ilex paraguariensis apresenta grande potencial de utilização pela diversidade de seus compostos químicos. Dentre os principais grupos de compostos presentes em erva mate citam-se as metilxantinas, com predominância de cafeína, teobromina e traços de teofilina. Na quantificação convencional destes compostos utiliza-se extração com solvente orgânico que expressa o conteúdo total de cafeína presente na amostra. Como forma alternativa de obtenção das metilxantinas pode-se utilizar a extração por fluído supercrítico (EFSC). Esta extração caracteriza-se pela obtenção de produtos de elevada qualidade, sem as inconveniências de resíduos de solventes e alterações nas propriedades do extrato presente na extração convencional. O objetivo deste trabalho foi quantificar metilxantinas presentes nas amostras de dezesseis progênies oriundas de quatro procedências (Ivaí/PR, Barão de Cotegipe/RS, Quedas do Iguaçu/PR e Cascavel/PR), cultivadas em três localidades (Ivaí/PR, Rio Azul/PR e Guarapuava/PR) utilizando a extração por solventes orgânicos e pela EFSC usando como solvente o CO2. As metilxantinas foram quantificadas por HPLC e espectrometria comparando-se com padrão. Os teores médios de metilxantinas, correspondendo à soma de cafeína e teobromina, foram de 19,112 mg/100 g nas progênies de Ivaí/PR, 8,906 mg/100 g nas progênies de Rio Azul/PR e de 12,796 mg/100 g nas progênies de Guarapuava/PR. Ao compararmos a extração supercrítica com a extração convencional de cafeína os valores médios encontrados foram de 2,808±0,7 % para Ivaí/PR, 1,537±0,2 % em Rio Azul/PR e 1,728±0,5 % para Guarapuava/PR. A EFSC usando o dióxido de carbono como solvente aliada à análise HPLC mostrou-se eficiente na caracterização e quantificação das metilxantinas presentes nas amostras analisadas.Seção: Controle de Qualidade/ Composição Química. Feira do Agronegócio da Erva-mate, 1., 2003, Chapecó. Integrar para promover o agronegócio da erva-mate
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