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551.
552.
Karl Thomas 《Die Naturwissenschaften》1963,50(20):629-630
553.
Karl A. Gingerich 《Die Naturwissenschaften》1967,54(24):646-647
554.
Karl Joachim Euler 《Die Naturwissenschaften》1966,53(14):341-348
555.
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Spatial statistical models that use flow and stream distance 总被引:6,自引:1,他引:6
Jay M. Ver Hoef Erin Peterson David Theobald 《Environmental and Ecological Statistics》2006,13(4):449-464
We develop spatial statistical models for stream networks that can estimate relationships between a response variable and
other covariates, make predictions at unsampled locations, and predict an average or total for a stream or a stream segment.
There have been very few attempts to develop valid spatial covariance models that incorporate flow, stream distance, or both.
The application of typical spatial autocovariance functions based on Euclidean distance, such as the spherical covariance
model, are not valid when using stream distance. In this paper we develop a large class of valid models that incorporate flow
and stream distance by using spatial moving averages. These methods integrate a moving average function, or kernel, against
a white noise process. By running the moving average function upstream from a location, we develop models that use flow, and
by construction they are valid models based on stream distance. We show that with proper weighting, many of the usual spatial
models based on Euclidean distance have a counterpart for stream networks. Using sulfate concentrations from an example data
set, the Maryland Biological Stream Survey (MBSS), we show that models using flow may be more appropriate than models that
only use stream distance. For the MBSS data set, we use restricted maximum likelihood to fit a valid covariance matrix that
uses flow and stream distance, and then we use this covariance matrix to estimate fixed effects and make kriging and block
kriging predictions.
Received: July 2005 / Revised: March 2006 相似文献
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Stenobrachius leucopsarus, the most abundant species of myctophid fishes off Oregon, USA, has a bimodal distribution at night, with a peak of abundance in the upper 100 m composed of diel vertical migrants, and another peak at 300 to 500 m composed of fish that did not migrate the night they were caught. We compared the feeding habits of these two groups of fish in an attempt to learn if deep fish migrated to surface waters. Low similarity of diets, differences in the rank order of common prey, and similar states of stomach fullness and digestion of prey suggest that fish captured in deep water at night probably did not feed exclusively in shallow water on previous nights. They probably fed in deep water. The similarity in food habits between deep and shallow fish is most readily explained by daytime feeding by fish in deep water and by broad vertical distributions of prey. 相似文献
560.
Summary The full song of the yellow-bellied sunbird (Nectarinia venusta) comprises distinct phrases, which retain their typical three-part structure and temporal organization regardless of the concentration of the sucrose solution provided. However, the sugar concentration does affect the types of elements that make up the initial part of the phrase and the number of elements in the terminal part. Several types of elements may be produced either as separate calls or as components of the initial part of the phrase; as the concentration decreases, at least two of these element types occur progressively more often in the phrases, taking the place of others. 相似文献