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排序方式: 共有170条查询结果,搜索用时 15 毫秒
1.
Abstract. This paper describes artificial neural network based pure significance tests for the unit root hypothesis against nonlinear alternatives. The theoretical properties of the tests are discussed and a Monte Carlo investigation of their small sample properties is undertaken.  相似文献   
2.
Up-to-date imaging approaches were used to address the spatiotemporal organisation of the endomembrane system in secretory cells of Dionaea muscipula. Different ‘slice and view’ methodologies were performed on resin-embedded samples to finally achieve a 3D reconstruction of the cell architecture, using ultrastructural tomography, array tomography, serial block face-scanning electron microscopy (SBF-SEM), correlation, and volume rendering at the light microscopy level. Observations of cryo-fixed samples by high-pressure freezing revealed changes of the endomembrane system that occur after trap activation and prey digestion. They provide evidence for an original strategy that adapts the secretory machinery to a specific and unique case of stimulated exocytosis in plant cells. A first secretion peak is part of a rapid response to deliver digestive fluids to the cell surface, which delivers the needed stock of digestive materials ‘on site’. The second peak of activity could then be associated with the reconstruction of the Golgi apparatus (GA), endoplasmic reticulum (ER) and vacuolar machinery, in order to prepare for a subsequent round of prey capture. Tubular continuum between ER and Golgi stacks observed on ZIO-impregnated tissues may correspond to an efficient transfer mechanism for lipids and/or proteins, especially for use in rapidly resetting the molecular GA machinery. The occurrence of one vacuolar continuum may permit continuous adjustment of cell homeostasy. The subcellular features of the secretory cells of Dionaea muscipula outline key innovations in the organisation of plant cell compartmentalisation that are used to cope with specific cell needs such as the full use of the GA as a protein factory, and the ability to create protein reservoirs in the periplasmic space. Shape-derived forces of the pleiomorphic vacuole may act as signals to accompany the sorting and entering flows of the cell.  相似文献   
3.
Throughout this account, the growing interest in management strategy, as a subject which can be planned, as well as described, by upper-echelon managers has been indicated.

The most important concept that has been outlined is that the need for a planned management strategy arises directly from the task which management sets itself when it tries to control its environment. It is not merely a need which becomes apparent at a high level of management complexity, but is inherently part of the function of management.

The second important idea, implicit throughout this account, and made explicit in §7, is that models of the organization are baaed on axioms which must be outlined at the highest level of control in an organization—by the board of directors : thus, the board have a direct influence, as well as ultimate responsibility, in the modelling activities of managers who construct and carry out planned strategic decisions.  相似文献   
4.
Certainty-equivalent decisions are risk neutral with respect to the uncertainty about outcomes. This paper examines risk-sensitive decisions which optimize a combination of the first two moments of a stochastic objective. These decisions are shown to be stochastically inseparable with respect to time, and cannot be fully optimized by recursive techniques such as dynamic programming. An example in economic planning shows that this inseparability property can have considerable significance in practice  相似文献   
5.
A multi-state deterministic system controlled via a noisy Binary Symmetric Channel (BSC) is modelled by an equivalent Markov chain. The system performs a random walk whose mean deviation from zero is numerically equal to the expected number of steps between zero crossings, and whose entropy is equal to the average amount of transmitted control information between zero crossings. Simple expressions are found for the received control information and for the mutual information via the BSC.  相似文献   
6.
Rice flour and yellow or white corn flour were combined at 50, 60 and 70% levels with mechanically deboned turkey and extrusion processed at 104C and 121C. The texture of the extrudates was evaluated by Warner-Bratzler shear (WBS), and flour concentration had more effect on the WBS values than flour type; treatments with 70% flour had significantly greater WBS values. Corn flour treatments and low temperature extrusion resulted in greater TBA values. Proximate composition of extrudates confirmed moisture losses during extrusion and that high temperature processing had mixed results on ether-extractable compounds.  相似文献   
7.
A technique is described for producing high quality emulsions in a controllable and reproducible way. The dispersed liquid phase is atomized electrostatically, thus enabling particle size to be well below 10μm for wax solutions while at the same time maintaining a very narrow particle size distribution. The energy saving over conventional emulsification methods is considerable, amounting to up to 85% for one typical domestic care product.
Emulsification is achieved in a one-step process in a machine which essentially has no moving parts and requires no auxiliary air supply. In addition to the ability to create high quality emulsions, electrostatic atomization of the dispersed phase itself introduces a new and useful parameter, electrical conductivity, enabling greater flexibility in terms of ensuring emulsion stability. Even in conventional emulsifier systems, electrically charging the dispersed phase may have important implications which have not to date been fully appreciated.
Emulsification de produits de soins de la peau et de produits de ménage par une méthode électrostatique  相似文献   
8.
9.
Abstract

This paper outlines a new approach to the synthesis of information from data. Information is defined as a detected organization of data after a process of discretization (or partitioning) and event covering. The discretization is based on a hierarchical maximum entropy scheme which iteratively minimizes the loss of information according to Shannon. The event-covering process is based on an evaluation of the deviation of the observed frequencies of an event from the expectation due to prior knowledge (defined by the null hypothesis and/or domain knowledge). The hierarchical maximum entropy discretization scheme provides a rigorous and efficient way in solving the non-uniform scaling problem in multivariate data analysis. Because our method refines the boundaries dynamically depending on the detection of information, it directs the analysis on the outcome subspace with high information content. In addition, it naturally produces a hierarchical view of information so that data can be analyzed/synthesized with respect to an outcome context. The method has been tested using simulated and real life data with very good result.  相似文献   
10.
Abstract

Problems of accurate discrimination between snow and cloud, together with the detection of the snow pack boundary, have handicapped the use of satellite data in operational snow-cover mapping systems. A technique, involving an unsupervised clustering procedure, is described which allows the removal of cloud areas using NOAA-9 Advanced Very High Resolution Radiometer (AVHRR) channel-1, channel-3 and channel-4 data in conditions of recent snow lie and a difference channel (channel-2 —channel-1 with channel-3 and channel-4) during periods of advanced snow melt. Accurate delineation of snow extent is provided by the techniques if these specified snow conditions are taken into account. A method for the identification of areas of marginal snow melt is also presented, based on comparisons with Landsat Thematic Mapper data. The classifications also enable the determination of snow areas influenced by cloud shadows and conifer forest in addition to separating areas of differing snow depth and percentage cover.  相似文献   
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