Insolation driven variations of Mercury’s lithospheric strength

Mercury's coupled 3:2 spin-orbit resonance in conjunction with its relatively high eccentricity of ~0.2 and near-zero obliquity results in both a latitudinal and longitudinal variation in annual average solar insolation and thus equatorial hot and cold regions. This results in an asymmetric temperature distribution in the lithosphere and a long wavelength lateral variation in lithosphere structure and strength that mirrors the insolation pattern. We employ a thermal evolution model for Mercury generating strength envelopes of the lithosphere to demonstrate and quantify the possible effects the insolation pattern has on Mercury's lithosphere. We find the heterogeneity in lithosphere strength is substantial and increases with time. We also find that a crust thicker than that of the Moon or Mars and dry rheologies for the crust and mantle are favorable when compared with estimates of brittle-ductile transition depths derived from lobate scarps. Regions of stronger and weaker compressive strength imply that the accommodation of radial contraction of Mercury as its interior cooled, manifest as lobate scarps, may not be isotropic, imparting a preferential orientation and distribution to the lobate scarps

Topographic power spectra of cratered terrains: Theory and application to the Moon

Impact cratering produces characteristic variations in the topographic power spectral density (PSD) of cratered terrains, which are controlled by the size-frequency distribution of craters and the spectral content (shape) of individual features. These variations are investigated here in two parallel approaches. First, a cratered terrain model, based on Monte Carlo emplacement of craters and benchmarked by an analytical formulation of the one-dimensional PSD, is employed to generate topographic surfaces at a range of size-frequency power law exponents and shape dependencies. For self-similar craters, the slope of the PSD, β, varies inversely with that of the production function, α, leveling off to 0 at high α (surface topography dominated by the smallest craters) and maintaining a roughly constant value (β ∼ 2) at low α (surface topography dominated by the largest craters). The effects of size-dependent shape parameters and various crater emplacement rules are also considered. Second, we compare the model-derived predictions for the behavior of the PSD with values of β calculated along transects from the Lunar Orbiter Laser Altimeter (LOLA). At small scales (∼115 m to 1 km) model predictions agree well with the PSD slope over the observed range of lunar size-frequency distributions. Differences between global PSD slopes at subkilometer and kilometer scales reflect a scale separation in roughness consistent with prior observations using a variety of surface roughness parameters. Understanding the statistical markers left by the impact cratering process on the lunar surface is useful for distinguishing between competing geological processes on planetary surfaces throughout the solar system

Mating rituals of the Slender Hognosed Pitviper

This is where the abstract of this record would appear. This is only demonstration data

Biochemical adaptations in early starvation: observations on sex difference.

Twenty-two students, eleven male and eleven female, volunteered to fast for 3 d. Twenty-four hour urine collections were obtained over the period of study, and total nitrogen, urea, and 3-hydroxybutyrate (3-OH-butyrate) were determined in each

Global surface slopes and roughness of the Moon from the Lunar Orbiter Laser Altimeter

The acquisition of new global elevation data from the Lunar Orbiter Laser Altimeter, carried on the Lunar Reconnaissance Orbiter, permits quantification of the surface roughness properties of the Moon at unprecedented scales and resolution. We map lunar surface roughness using a range of parameters: median absolute slope, both directional (along-track) and bidirectional (in two dimensions); median differential slope; and Hurst exponent, over baselines ranging from ~17 m to ~2.7 km. We find that the lunar highlands and the mare plains show vastly different roughness properties, with subtler variations within mare and highlands. Most of the surface exhibits fractal-like behavior, with a single or two different Hurst exponents over the given baseline range; when a transition exists, it typically occurs near the 1 km baseline, indicating a significant characteristic spatial scale for competing surface processes. The Hurst exponent is high within the lunar highlands, with a median value of 0.95, and lower in the maria (with a median value of 0.76). The median differential slope is a powerful tool for discriminating between roughness units and is useful in characterizing, among other things, the ejecta surrounding large basins, particularly Orientale, as well as the ray systems surrounding young, Copernican-age craters. In addition, it allows a quantitative exploration on mare surfaces of the evolution of surface roughness with age

Role of immediate reconstruction for elderly breast cancer patients

With rising numbers of elderly women developing breast cancer, treatment options must evolve which take into consideration quality of life and functional status. Although fewer women at all ages are undergoing mastectomy, for those elderly women who undergo mastectomy, reconstruction options should be offered. Over the past 5 years, increasing numbers of elderly women are electing immediate reconstruction (IM)

Breast specific gamma imaging: Role in evaluation of breast disease

Although mammography is the gold standard for screening for breast cancer, 10 to 15% of lesions are missed, and this is higher with dense breasts. Alternative diagnostic modalities are being developed. One of these, breast specific gamma imaging (BSGI), which is not effected by dense tissue, utilizes the increased metabolic activity of tumors to localize and distinguish benign from malignant processes in the breast. The test can be used for screening and diagnostic purposes