Trocas gasosas em folhas de diferentes estádios de desenvolvimento em genótipos de mamoeiro (Carica Papaya L.)

ABSTRACTNeste trabalho, utilizaram-se quatro genótipos de mamoeiro, sendo três genótipos do grupo 'Solo' (Sunrise Solo TJ, Sunrise Solo 72/12 e Baixinho de Santa Amália) e um do grupo 'Formosa' (Know-You 01). As plantas foram cultivadas em potes plásticos, sob condição de casa de vegetação, num solo franco-argilo-arenoso, corrigido, adubado e submetidas a irrigações periódicas até a capacidade de campo. Em todos os genótipos, a taxa fotossintética líquida (A, mmol m-2 s-1), a condutância estomática (gs, mol m-2 s-1), a temperatura foliar (Tl, 0C), a concentração interna de CO2 (ci, mL L-1) no mesofilo foliar foram determinadas aos 73 dias após o plantio (DAP), na 4a, 5a, 6a, 7a, 8a e 9a folhas, contadas a partir do ápice, por meio de um analisador de gás no infravermelho modelo LI-6200. Entre as folhas amostradas e entre os genótipos estudados, não foram observadas diferenças significativas nos valores de A, gs, ci e Tl. Foi observado que elevados valores de gs proporcionaram valores elevados de A em todos os genótipos estudados. Contudo, para a característica Tl, as relações com gs foram inversas, evidenciando a fundamental função do processo transpiratório no resfriamento foliar. Os resultados indicaram que, em todos os genótipos estudados, as folhas avaliadas funcionaram como órgãos fontes.In this research, was used four papaya (Carica papaya L.) genotypes: three from the 'Solo ( Sunrise Solo TJ, Sunrise Solo 72/12 and Baixinho de Santa Amália) group and one from the 'Formosa' group (Know-You 01). They were grown in plastic pots containing a sandy-clay-loam soil subjected to pH correction and fertilization, under greenhouse conditions. Throughout the experimental period plants were subjected to periodic irrigation to maintain the soil humitidy around field capacity. The experiment was conducted 73 days after sowing. In all genotypes, leaf gas exchange characteristics were determined. The net photosynthetic rate (A, mmol m-2 s-1 ), stomatal conductance (gs mol m-2 s-1), leaf temperature (TI, 0C) and intercellular carbon dioxide concentration (ci, mL L-1) on the 4th, 5th, 6th, 7th, 8th and 9th leaves from the plant apex were determined. No significant differences were observed for A, gs, ci, or Tl either among the leaves sampled from any of the genotypes. A was positively correlated with gs and in the other hand TI and gs were negatively correlated. The results suggest that, for 73 DAP, all the sampled papaya leaves functioned as sources of organs

Maximization of an Asymmetric Utility Function by the Least Squares

This note points out that a utility maximization procedure proposed in an earlier paper may be reduced to the least squares.The utility function is asymmetric in the sense that for each cue an ideal value and a permissible range are assigned in such a way that the ideal value is not necessarily at the center of the interval, like "a beer of 350 [ml] would be ideal, but acceptable if within [100, 500]". A practical consequence of the observation is that very little programming will be needed to deploy the utility maximization, since software for the least squares is widely available

Maximization of an Asymmetric Utility Function by the Least Squares

Abstract. This note points out that a utility maximization procedure proposed in an earlier paper may be reduced to the least squares. The utility function is asymmetric in the sense that for each cue its ideal value and the permissible range are assigned in such a way that the ideal is not necessarily at the center of the range, like "a beer of 350 ml would be ideal, but acceptable if within [100, 500]". A practical consequence of the observation is that very little programming will be needed to deploy the utility maximization since software for the least squares is widely available

Vacant rooms? The secondary use of stem-galls by ants in Eremanthus erythropappus (Asteraceae)

Galls are atypical proliferations of plant tissue induced by highly specialized herbivores, such as some insect groups. Although gall inducers create these structures for their own purpose (food, habitat, protection against natural enemies, and harsh weather), many other organisms can use galls as secondary inhabitants. The creation of new and better habitats with ameliorated micro-environmental conditions allows for the use of many other organisms, and as such, some galling insects are considered "micro" ecosystem engineers. This study characterized the occurrence of ants in microhabitats created by a gall-inducing cecidomyiidae associated with Eremanthus erythropappus (DC.) Mac. Leish (Asteraceae). It was 153 individuals of ants belonging to three species in 19 galls (9.5%) from the 200 galls sampled. The most common ant species found was Myrmelachista gallicola Mayr (Formicinae), including a single queen and larvae individuals. Galls occupied by these ants were 11.5% larger compared to unoccupied galls (gall diameter: occupied galls - 10.00 ± 2.09 mm; unoccupied galls - 8.97 ± 1.90 mm). Abandoned galls might promote the diversity of other organisms, especially for opportunistic dwellers such as ants

Stretching the Least Squares to Embed Loss Functions Tables

The method of least squares is extended to accommodate a class of loss functions specified in the form of function tables. Each function table is embedded into the standard quadratic loss function so that the nonlinear least squares algorithms can be adopted for loss minimization. This is an alternative to a more conventional approach which interpolates the function tables and minimizes the resulting loss function by some generic optimization algorithm. An advantage of the alternative over the conventional approach is the wider availability of the least squares programs compared to the generic optimization programs, especially on resource-constrained devices. Examples are given for its application to multiplicative utility function maximization problems

Propuesta de implementación de la metodología BIM por medio del diseño y desarrollo de un proyecto piloto tipo residencial

El presente trabajo con metodología BIM optimiza cada fase del proyecto, desde el diseño previo hasta el control y operación de la obra en comparación con la metodología tradicional, con el objetivo de minimizar tiempos improductivos de planificación, organización, dirección y control, para la potencialización de los lineamientos a seguir en cada etapa, para la mejora continua del proceso de diseño y construcción; facilitando el análisis de las variables involucradas en la gestión del proyecto, para la mitigación de los diversos factores técnicos, financieros y operativos que pueden retrasar la ejecución de la obra

Modelo matemático de câmara fria para armazenamento de produtos agrícolas

Studies of control strategies for refrigeration systems observe, among other variables, the dynamic behavior of temperature and the consumption of electrical energy. Aiming to contribute to these studies, this work presents the proposal and validation of a mathematical model for the cooling system of a cold-storage unit. The model approximates the dynamics and interdependence of the variables, to first-order systems with time delay and the summation of effects. The input variables available are the frequency of compressor activation and the thermal load imposed on the unit, and as output variables, the air temperature both at the evaporator inlet and at the centre of the chamber, as well as the electrical power consumed by the compressor. The results obtained were satisfactory, with an error of less than 0.11 ºC for the air temperature at the evaporator inlet, of less than 0.09 ºC for the temperature at the centre of the chamber, and of less than 1% for the electrical energy consumed.Os estudos de estratégias de controle para sistemas de refrigeração observam, entre outras variáveis, o comportamento dinâmico da temperatura e da energia elétrica consumida. Com o objetivo de contribuir com estes estudos, o presente trabalho apresenta a proposta e a validação de um modelo matemático do sistema de refrigeração de uma câmara fria. O modelo aproxima a dinâmica e a interdependência das variáveis a sistemas de primeira ordem com tempo de atraso e somatória de efeitos. Como variáveis de entrada tem-se a frequência de acionamento do compressor e a carga térmica imposta à câmara e como variáveis de saída as temperaturas do ar na entrada do evaporador e no centro da câmara, bem como a potência elétrica consumida pelo compressor. Os resultados obtidos foram satisfatórios, com erro menor que 0,11 ºC para a temperatura do ar na entrada do evaporador, menor que 0,09 ºC para a temperatura do ar no centro da câmara e menor que 1% para energia elétrica consumida.28629