146 resultados para Weckman, Knut,
Resumo:
Mode of access: Internet.
Resumo:
"Drittes Tausend."
Resumo:
Anmerkninger.
Resumo:
An integrated production–recycling system is investigated. A constant demand can be satisfied by production and recycling. The used items might be bought back and then recycled. The not recycled products are disposed off. Two types of models are analyzed. The first model examines and minimizes the EOQ related cost. The second model generalizes the first one by introducing additionally linear waste disposal, recycling, production and buyback costs. This basic model was examined by the authors in a previous paper. The main results are that a pure strategy (either production or recycling) is optimal. This paper extends the model for the case of quality consideration: it is asked for the quality of the bought back products. In the former model we have assumed that all returned items are serviceable. One can put the following question: Who should control the quality of the returned items? If the suppliers examine the quality of the reusable products, then the buyback rate is strongly smaller than one, α<1. If the user does it, then not all returned items are recyclable, i.e. the use rate is smaller than one, δ<1. Which one of the control systems are more cost advantageous in this case?
Resumo:
Iridescent blue leaf coloration in two neotropical ferns, Danaea nodosa (L.) Sm. (Marattiaceae) and Trichomanes elegans L. C. Rich. (Hymenophyllaceae), is caused by thin film constructive interference. The ultrastructural basis for the film in D. nodosa is multiple layers of cellulose microfibrils in the adaxial cell walls of the adaxial epidermis. The apparent helicoidal arrangement of the fibrils is analogous to similar color production in arthropods. In T. elegans the blue-green coloration is caused by the remarkably uniform thickness and arrangement of grana in specialized chloroplasts adjacent to the adaxial wall of the adaxial epidermis. The selective advantage of this color production, if any, is unknown but apparently different from that previously studied in Selaginella.
Resumo:
This study is based on rock mechanical tests of samples from platform carbonate strata to document their petrophysical properties and determine their potential for porosity loss by mechanical compaction. Sixteen core-plug samples, including eleven limestones and five dolostones, from Miocene carbonate platforms on the Marion Plateau, offshore northeast Australia, were tested at vertical effective stress, sigma1', of 0-70 MPa, as lateral strain was kept equal to zero. The samples were deposited as bioclastic facies in platform-top settings having paleo-water depths of <10-90 m. They were variably cemented with low-Mg calcite and five of the samples were dolomitized before burial to present depths of 39-635 m below sea floor with porosities of 8-46%. Ten samples tested under dry conditions had up to 0.22% strain at sigma1' = 50 MPa, whereas six samples tested saturated with brine, under drained conditions, had up to 0.33% strain. The yield strength was reached in five of the plugs. The measured strains show an overall positive correlation with porosity. Vp ranges from 3640 to 5660 m/s and Vs from 1840 to 3530 m/s. Poisson coefficient is 0.20-0.33 and Young's modulus at 30 MPa ranged between 5 and 40 GPa. Water saturated samples had lower shear moduli and slightly higher P- to S-wave velocity ratios. Creep at constant stress was observed only in samples affected by pore collapse, indicating propagation of microcracks. Although deposited as loose carbonate sand and mud, the studied carbonates acquired reef-like petrophysical properties by early calcite and dolomite cementation. The small strains observed experimentally at 50 MPa indicate that little mechanical compaction would occur at deeper burial. However, as these rocks are unlikely to preserve their present high porosities to 4-5 km depth, further porosity loss would proceed mainly by chemical compaction and cementation.
Resumo:
Las relaciones entre los gabinetes de Comunicación de los clubes de fútbol y los periodistas deportivos se enmarcan en el modelo de Gieber y Johnson (1961) por el que el hecho de que ambos compartan objetivos comunes, donde los gabinetes de Comunicación necesitan que los medios publiquen determinadas informaciones y los periodistas precisan de noticias que publicar, provoca una pérdida de independencia por parte de los periodistas, ya que necesitan a esos departamentos como fuentes. En la actualidad, los departamentos de Comunicación de los clubes de fútbol, como el del FC Barcelona, se han constituido en gatekeepers. Esto ha acentuado las históricas diferencias que existen entre los periodistas y los profesionales de la comunicación corporativa, incrementado por el control informativo de estos departamentos lo que provoca constantes tensiones entre ambos.
Resumo:
Las disputas en torno a determinados aspectos del dinero, como su neutralidad y el carácter endógeno o exógeno de la oferta monetaria, han sido permanentes entre las distintas escuelas de pensamiento y autores, estando su origen, probablemente, en la época de desarrollo del pensamiento escolástico. En este artículo pretendemos, en primer lugar, realizar un recorrido cronológico e histórico sobre el tratamiento científico económico del dinero, para, en segundo lugar, poner sobre la mesa la macroeconomía ortodoxa a la que han dado lugar las interpretaciones al respecto, así como los enfoques alternativos frente a este pensamiento dominante. Finalmente, intentamos poner en valor los desarrollos monetarios post-keynesianos, integrados en lo que denominan “Economía Monetaria de Producción”, confrontándolos con la llamada Nueva Síntesis Neoclásica.
Resumo:
Der vorliegende Beitrag beschäftigt sich mit der Frage ob Lenks Modell zur Erfassung von grundsätzlichen Determinanten der LehrerInnenverantwortung, das durch Lauermann und Karabenick übernommen wurde, empirisch gestützt werden kann. Ziel dieses Beitrags ist es, kausale Beziehungen innerhalb dieses Modells mit Hilfe eines Strukturgleichungsmodells zu bewerten. Basierend auf Daten einer norwegischen LehrerInnenuntersuchung ergaben sich deutliche Zusammenhänge zwischen den Elementen des Modells. Relationales Vertrauen, informelles Lernen zwischen den LehrerInnen und wahrgenommene Unterstützung durch SchulleiterInnen haben sich als wichtige Determinanten für die LehrerInnenverantwortung erwiesen, wenngleich die kontextuellen Faktoren in ihrer Eigenart komplexer zu sein scheinen. Es bedarf weiterer Forschung, um diese zu verstehen. Angesichts der Ergebnisse ist zu empfehlen, dass Schulbehörden einen Schwerpunkt auf die Gestaltung einer Politik legen, die die Vertrauensbeziehungen zwischen den LehrerInnen berücksichtigt. (DIPF/Orig.)
Resumo:
No era Ernest Lluch individuo propenso a adoptar un singular libro de cabecera, ni a seguir con fidelidad las huellas de un único maestro. Pero, por supuesto, tenía su personal esquema devalores y sus escalas de preferencias. Y uno de los autores que sin discusión estaba presente en su galería privada de economistas ilustres fue Piero Sraffa (1898-1983). Creo que también habríacolocado en esa división de honor a François Quesnay, Adam Smith, David Ricardo, Karl Marx, Knut Wicksell, John M. Keynes, Joseph A.Schumpeter, Maurice H. Dobb, Wassily Leontief, John K. Galbraith, Paolo Sylos Labini y Albert O. Hirschman.