Progressive, diabetes-associated ovarian atrophy was analyzed in C57BL/KsJ diabetic (db/db) and control (+/?) mice between 2 and 16 weeks of age. Tissue changes were histologically and morphometrically analyzed and compared with ovarian functional indices (i.e., serum estradiol and progesterone) and metabolic (i.e., glucose uptake and estradiol sequestration) parameters. No significant differences were found between the ovarian follicular populations of either group at 2 and 4 weeks of age. However, between 4 and 8 weeks, the ovaries of diabetic mice exhibited marked stromal and follicular degeneration and an associated decline in the population of viable follicles as compared with controls. Between 8 and 16 weeks of age the follicular atrophy in the diabetics became more marked, as compared with controls, with the accumulation of intracellular lipid pools accenting the tissue degeneration and adiposity observed in both follicular and stromal compartments. In addition, ovarian function was depressed after 6 weeks of age in diabetic females as compared with controls as indicated by lowered serum estradiol and progesterone levels. Ovarian glucose uptake was enhanced in diabetic females while the ability of the ovary to sequester radiolabeled estradiol declined between 4 and 16 weeks of age as compared with controls. These data indicate that ovarian dysfunction in the (db/db) mutant mouse is associated with follicular atrophy, adiposity, impaired steroidogenesis, and imbalanced glucose utilization. These events occur in temporal association with the onset and progressive exacerbation of the hyperglycemic condition. It is suggested that ovarian involution in these mutants is directly related to an impaired follicular ability to metabolize properly the elevated intracellular glucose concentrations that develop in the (db/db) mice as compared with controls.

We present a novel technique estimating the vertical component of particle motion from marine single-component pressure data. The particle motion data, bar an angle-dependent obliquity factor, is computed by convolution of the output from L1 deconvolution of the pressure ghost wavelet with the corresponding ghost wavelet of the particle motion. The estimated particle motion data is then used in a conventional 2D technique for receiver ghost attenuation by combination with the original pressure-wave data. The proposed new technique operates in the τ-[Formula: see text] domain of individual shot-streamer records and in overlapping windows along the intercept-time axis. In each window, the L1 deconvolution is achieved by an iteratively reweighted-norm least squares algorithm. We applied our technique to deep-tow streamer data of a 3D over/sparse-under marine survey, in which six streamers were towed at a shallow depth, with two additional streamers towed deeper. Over/sparse-under technology allows using seismic measurements from a shallow streamer to be complemented by a low-frequency limited measurement from a deep streamer to achieve an estimate of the up-going pressure wave recording. The low frequencies of the deep streamer are used to boost the low frequencies of the shallow streamer, which have been heavily attenuated by the shallow tow ghost response. Our technique achieves, on this particular data, set improvements in bandwidth of the single-component pressure data, while not fully reaching the quality of the optimally deghosted data from the over/sparse-under survey.

Scattered ground roll is a type of noise observed in land seismic data that can be particularly difficult to suppress. Typically, this type of noise cannot be removed using conventional velocity‐based filters. In this paper, we discuss a model‐driven form of seismic interferometry that allows suppression of scattered ground‐roll noise in land seismic data. The conventional cross‐correlate and stack interferometry approach results in scattered noise estimates between two receiver locations (i.e. as if one of the receivers had been replaced by a source). For noise suppression, this requires that each source we wish to attenuate the noise from is co‐located with a receiver. The model‐driven form differs, as the use of a simple model in place of one of the inputs for interferometry allows the scattered noise estimate to be made between a source and a receiver. This allows the method to be more flexible, as co‐location of sources and receivers is not required, and the method can be applied to data sets with a variety of different acquisition geometries. A simple plane‐wave model is used, allowing the method to remain relatively data driven, with weighting factors for the plane waves determined using a least‐squares solution. Using a number of both synthetic and real two‐dimensional (2D) and three‐dimensional (3D) land seismic data sets, we show that this model‐driven approach provides effective results, allowing suppression of scattered ground‐roll noise without having an adverse effect on the underlying signal.

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