Grade is a condition of equilibrium in streams as agents of transportation. The validity of the concept has been questioned, but it is indispensable in any genetic study of fluvial erosional features and deposits. This paper modifies and extends the theory of grade originally set forth by Gilbert and Davis. A graded stream is one in which, over a period of years, slope is delicately adjusted to...

How to calculate the goodness-of-fit of a fractal dimension To the Editor, Karyometric data are helpful for differential diagnosis and prognosis [1–4]. A new morphometric variable, the coefficient of determination of the Minkowski frac-tal dimensions (the R 2 value between the y of the regression lines and y values of the real data) has recently been introduced [1,2]. Adam et al. [1] described ...

We present a fast algorithm for slope detection on gray scale images, based on 2D Fourier transform and standard filters; this may be used for line or edge detection. Our approach is based on the calculation of “energy” per direction of the image, thus obtaining the “energy spectrum on slope” ( ). This exhibits local maxima at the points where equals the slopes of linear or quasi-linear segment...

W e study the variations of the received frequencies (Complex Doppler effect) from a source moving uniformly in a homogeneous isotropic plasma and emitting a uniform EM plane wave with amplitude E0 , as a function of coe/Eo where coe is the plasma frequency. The ratio of the velocity U of the source over the group velocity UgT of the transmitted wave is then calculated from the slope of the Dop...

Adult listeners heard a pure-tone glide ("captor") repeatedly alternating with a complex glide consisting of three simultaneous pure-tone glides. One of the pure-tone glide components in the complex glide matched the captor glide in its frequency center, orientation, and direction. This component was referred to as the "target:’ The two other glides in the complex glide were referred to as "the...

[1] The availability of high resolution topography from LIDAR offers new opportunities for objectively extracting the channels directly from a DEM using local topographic information, instead of inferring them indirectly based on global criteria, such as area or area-slope threshold relationships. Here we introduce the use of wavelet filtering to delineate threshold curvatures for defining vall...

A field-portable 3D laser scanner was employed as a means of digitizing the surface of fire ant ( Solenopsis invicta Buren) mounds for analysis of shape and orientation in Mississippi and Oklahoma. Estimates of above-ground mound volume obtained through manual measurements of mound length, width, and height were higher and more variable than estimates obtained by summing the area underneath int...

Energy relations derived for a lossless closed uniform and periodic structure show that the total complex Poynting vector Integrated over the cross section Is Identically zero for the case of an arbitrary complex wave. These results are also applicable to open structurrs provided certain conditions are satisfied. The application of these results in the field of leaky wave antennas is discussed,...

laska has accepted two Stranded Gas Applications that will allow North Slope producers to enter into negotiations on terms to construct natural gas pipelines to the Lower 48. The applications, which suggest that the future for major pipelines to bring natural gas to the U.S. remains bright, also indicate the rising competitive interest in building such a pipeline. Alaska Gov. Frank Murkowski an...

[1] We conduct laboratory experiments and direct numerical simulations on internal gravity waves generated by tidal flow over a model three‐dimensional Gaussian mountain on the sea floor. When 2w < N (where w is the tidal frequency and N is the buoyancy frequency), the flow generates second harmonic internal waves that propagate perpendicular to the tidal forcing direction. These unexpected har...