Impact Response of Granular Soils

The paper describes results from an extensive experimental model study of response of dry sand to impact of a rigid pounder. In the laboratory tests a circular steel pounder was repeatedly dropped on sand contained in a large tank. Measurements included pounder acceleration and soil pressure at impact, pounder settlement, and soil densities and strains. Effects of pounder drop height, weight and contact area were investigated. A method is presented for the evaluation of global dynamic stiffness of the so1l mass affected by the impact by calculating a dynamic settlement modulus (DSM). The DSM values are determined from integration of the impact acceleration record with respect to time using measured integration constants. DSM values show good correlation to soil densities and corresponding elastic moduli obtained from laboratory tests. The proposed method may have immediate construction application as it offers a reliable and cost effective alternative to quality control of dynamic compaction

Soil Profiling by Spectral Analysis of Surface Waves

Methods for in-situ surface measurement and spectral analysis of Rayleigh waves for subsurface soil investigation have been tried by several researchers in recent years. The two most common methods, steady-state Rayleigh-wave and spectral-analysis-of-surface-waves (SASW) have certain disadvantages and are not used for routine soil investigation. The paper presents a system which uses a controlled vibration source with amplitude modulation and variable frequency capabilities. The electromagnetic vibrator may be varied in size and weight according to the depth of the soil strata investigated. The Rayleigh wave phase velocity dispersion curves are used to compute apparent velocity distribution in depth. An approximate conversion method is then used to estimate Rayleigh wave velocity profiles of the layered soil from the apparent velocities distributions. Shear wave velocities, computed by using established theoretical relationship, may then be used to obtain design parameters for the soil strata. The system has been used routinely in Japan and South East Asia for several years now and results show good correlations with SPT and shear wave velocity measurements conducted as verification tests in a variety of sites

Internet Daters’ Body Type Preferences: Race–Ethnic and Gender Differences

Employing a United States sample of 5,810 Yahoo heterosexual internet dating profiles, this study finds race–ethnicity and gender influence body type preferences for dates, with men and whites significantly more likely than women and non-whites to have such preferences. White males are more likely than non-white men to prefer to date thin and toned women, while African-American and Latino men are significantly more likely than white men to prefer female dates with thick or large bodies. Compatible with previous research showing non-whites have greater body satisfaction and are less influenced by mainstream media than whites, our findings suggest Latinos and African Americans negotiate dominant white idealizations of thin female bodies with their own cultures’ greater acceptance of larger body types

Chemoreception Regulates Chemical Access to Mouse Vomeronasal Organ: Role of Solitary Chemosensory Cells

Controlling stimulus access to sensory organs allows animals to optimize sensory reception and prevent damage. The vomeronasal organ (VNO) detects pheromones and other semiochemicals to regulate innate social and sexual behaviors. This semiochemical detection generally requires the VNO to draw in chemical fluids, such as bodily secretions, which are complex in composition and can be contaminated. Little is known about whether and how chemical constituents are monitored to regulate the fluid access to the VNO. Using transgenic mice and immunolabeling, we found that solitary chemosensory cells (SCCs) reside densely at the entrance duct of the VNO. In this region, most of the intraepithelial trigeminal fibers innervate the SCCs, indicating that SCCs relay sensory information onto the trigeminal fibers. These SCCs express transient receptor potential channel M5 (TRPM5) and the phospholipase C (PLC) β2 signaling pathway. Additionally, the SCCs express choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT) for synthesizing and packaging acetylcholine, a potential transmitter. In intracellular Ca2+ imaging, the SCCs responded to various chemical stimuli including high concentrations of odorants and bitter compounds. The responses were suppressed significantly by a PLC inhibitor, suggesting involvement of the PLC pathway. Further, we developed a quantitative dye assay to show that the amount of stimulus fluid that entered the VNOs of behaving mice is inversely correlated to the concentration of odorous and bitter substances in the fluid. Genetic knockout and pharmacological inhibition of TRPM5 resulted in larger amounts of bitter compounds entering the VNOs. Our data uncovered that chemoreception of fluid constituents regulates chemical access to the VNO and plays an important role in limiting the access of non-specific irritating and harmful substances. Our results also provide new insight into the emerging role of SCCs in chemoreception and regulation of physiological actions

The ontogeny of antipredator behavior: age differences in California ground squirrels (Otospermophilus beecheyi) at multiple stages of rattlesnake encounters

Newborn offspring of animals often exhibit fully functional innate antipredator behaviors, but they may also require learning or further development to acquire appropriate responses. Experience allows offspring to modify responses to specific threats and also leaves them vulnerable during the learning period. However, antipredator behaviors used at one stage of a predator encounter may compensate for deficiencies at another stage, a phenomenon that may reduce the overall risk of young that are vulnerable at one or more stages. Few studies have examined age differences in the effectiveness of antipredator behaviors across multiple stages of a predator encounter. In this study, we examined age differences in the antipredator behaviors of California ground squirrels (Otospermophilus beecheyi) during the detection, interaction, and attack stages of Pacific rattlesnake (Crotalus oreganus) encounters. Using free-ranging squirrels, we examined the ability to detect free-ranging rattlesnakes, snake-directed behaviors after discovery of a snake, and responses to simulated rattlesnake strikes. We found that age was the most important factor in snake detection, with adults being more likely to detect snakes than pups. We also found that adults performed more tail flagging (a predator-deterrent signal) toward snakes and were more likely to investigate a snake’s refuge when interacting with a hidden snake. In field experiments simulating snake strikes, adults exhibited faster reaction times than pups. Our results show that snake detection improves with age and that pups probably avoid rattlesnakes and minimize time spent in close proximity to them to compensate for their reduced reaction times to strikes

Earthquake Induced Landslides in Columbia

The paper presents a case study of landslides associated with the 1983 Popayan earthquake in Colombia. It includes a systematic parametric study of the effect of earthquake characteristics and soil properties on slope behavior. Earthquake induced slope displacements are computed based on the sliding block concept. Computed results from two and three-dimensional analyses are compared with field observations. Conclusions are drawn in regard to the adequacy of analysis procedures, validity of slope deformation-critical acceleration curves, and effect of vertical acceleration on slope stability

The self-reported importance of olfaction during human mate choice

This study evaluated sex differences in the relative importance placed on olfactory cues during mate choice. To evaluate this 151 men and 289 women completed an on-line version of the Romantic Interests Survey (RIS) (Herz & Inzlict, 2002). Olfactory characteristics were declared to be extremely important during mate selection, more so than almost all other characteristics, but did not significantly differ between the sexes. There were significant differences concerning the odour source that individuals attend to, with greater preferences observed for a potential mate?s body odour as opposed to artificial fragrances they use. These findings suggest the body odour characteristics of a potential mate are perceived to be an important factor during mate choice