Techniques for Resolving Incomplete Systems in K-Systems Analysis.

K-systems analysis is a generalization of reconstructability analysis (RA), where any general, complete multivariate system (g-system) can be transformed into an isomorphic, dimensionless system (a K-system) that has sufficient properties to be analyzed using probabilistic RA algorithms. In particular, a g-system consists of a set of states formed from a complete combination of the variables assigned specific values from a finite set of possible values and an associated system function value. The g-system must be complete in that all possible states must have an associated system function value. K-systems analysis has been applied to a variety of systems, but many real-world systems consist of data that is incomplete. Impediments in real-world systems have been previously identified as state contradictions, data scattering and missing data [JONE 85d]. The problem of state contradictions has been adequately addressed, but while techniques for the resolution of data scattering and missing data have been proposed, additional issues remain. The author has condensed the understanding of data scattering and missing data into the single problem of an incomplete system. Within this context, techniques for resolving incomplete systems and, thereby, inducing a complete system have been developed. If a g-system is incomplete, it may be viewed solely from the perspective of missing data. A new algorithm has been developed based on the state distance and uses this distance to determine unbiased estimates of the values for the system function. The state distance is a generalized Hamming distance and is shown to satisfy the properties of a metric on the state space and to be superior to current methods for imputing system function values. An incomplete system may be viewed from the perspective of data scattering. In general, scattered data may be resolved through clustering and, previously, this clustering has been done in one dimension. A method is developed that allows the meaningful use of two dimensions in the clustering. Further, a new pairwise similarity measure is developed based on the maximum entropy principle and mathematics that form the foundation of K-systems analysis. Use of this similarity measure is demonstrated within the context of an existing clustering algorithm

The subarcsecond mid-infrared view of local active galactic nuclei: II. The mid-infrared--X-ray correlation

We present an updated mid-infrared (MIR) versus X-ray correlation for the local active galactic nuclei (AGN) population based on the high angular resolution 12 and 18um continuum fluxes from the AGN subarcsecond MIR atlas and 2-10 keV and 14-195 keV data collected from the literature. We isolate a sample of 152 objects with reliable AGN nature and multi-epoch X-ray data and minimal MIR contribution from star formation. Although the sample is not homogeneous or complete, we show that our results are unlikely to be affected by biases. The MIR--X-ray correlation is nearly linear and within a factor of two independent of the AGN type and the wavebands used. The observed scatter is <0.4 dex. A possible flattening of the correlation slope at the highest luminosities probed (~ 10^45 erg/s) is indicated but not significant. Unobscured objects have, on average, an MIR--X-ray ratio that is only <= 0.15 dex higher than that of obscured objects. Objects with intermediate X-ray column densities (22 < log N_H < 23) actually show the highest MIR--X-ray ratio on average. Radio-loud objects show a higher mean MIR--X-ray ratio at low luminosities, while the ratio is lower than average at high luminosities. This may be explained by synchrotron emission from the jet contributing to the MIR at low-luminosities and additional X-ray emission at high luminosities. True Seyfert 2 candidates and double AGN do not show any deviation from the general behaviour. Finally, we show that the MIR--X-ray correlation can be used to verify the AGN nature of uncertain objects. Specifically, we give equations that allow to determine the intrinsic 2-10 keV luminosities and column densities for objects with complex X-ray properties to within 0.34 dex. These techniques are applied to the uncertain objects of the remaining AGN MIR atlas, demonstrating the usefulness of the MIR--X-ray correlation as an empirical tool.Comment: Accepted for publication in MNRAS, 40 pages, 25 figure

Níveis de danos do nematóide de cisto da soja.

bitstream/item/24729/1/COT200269.pdfDocumento on-line

Reprodução do nematoide de galhas em plantas forrageiras utilizadas em sistemas integrados de produção agropecuária.

bitstream/item/39450/1/Cot28-98.pd

Reprodução de Meloidogyne javanica em algumas plantas daninhas de ocorrência freqüente na Regiao Oeste do Brasil.

bitstream/item/39434/1/Cot19-97.pd