Taphonomic Studies of Elephant Mortality in Zimbabwe

In an effort to develop guidelines for paleoecological interpretations of mortality among extinct proboscideans, the author has been gathering data on demography of drought-killed elephants and those culled in Zimbabwe’s National Parks since 1981. Included here are preliminary figures on average ages of animals in cull and die-off samples as well as some preliminary information on age distributions. Culled elephants provide invaluable scientific data in addition to the revenue obtained from sale of elephant ivory, skin and meat

Utilization and Skeletal Disturbances of North American Prey Carcasses

More than 125 carcasses and skeletal remains of wild bison, moose, and whitetail deer were examined in the field. Most were from closely documented episodes of predation, mass drownings, or other natural causes of death. Predictable and unusual kinds of bone and carcass utilization by timber wolves and bears are described. The variables emphasized include sectioning of carcasses by feeding predators, distribution and dispersal of bones at kill sites, gnaw damage to bones in homesites, kill sites and scavenge sites, potential or observed survival of bones at sites of prey carcasses, and the patterns of scatter or accumulation of skeletal remains in moose and bison ranges due to predation or other natural causes of death. Variations in gnaw damage to bones and utilization of carcasses by carnivores reflect significant aspects of predator-prey interactions, and can be deciphered by ecologists interpreting either fossil or modern assemblages of bones.Key words: carnivores, prey carcasses, taphonomy, North America, paleoecology, archeological interpretationMots clés: carnivores, carcasses de proies, taphonomie, Amérique du Nord, paléoécologie, interprétation archéologiqu

Which patients undergoing noncardiac surgery benefit from perioperative beta-blockers?

Patients with moderate to high cardiac risk (a Revised Cardiac Risk Index [RCRI] score of 2 or higher [Table]) have a reduced risk of in-hospital death following perioperative beta-blocker therapy (strength of recommendation [SOR]: B, based on a large retrospective cohort study). There is, however, no proven benefit to perioperative beta-blocker therapy without prior cardiac risk stratification (SOR: A, based on systematic reviews)

The I-Band Tully-Fisher Relation for Sc Galaxies: Optical Imaging Data

Properties derived from the analysis of photometric I-band imaging observations are presented for 1727 inclined spiral galaxies, mostly of types Sbc and Sc. The reduction, parameter extraction, and error estimation procedures are discussed in detail. The asymptotic behavior of the magnitude curve of growth and the radial variation in ellipticity and position angle are used in combination with the linearity of the surface brightness falloff to fit the disk portion of the profile. Total I-band magnitudes are calculated by extrapolating the detected surface brightness profile to a radius of eight disk scale lengths. Errors in the magnitudes, typically ~0.04 mag, are dominated by uncertainties in the sky subtraction and disk-fitting procedures. Comparison is made with the similar imaging database of Mathewson, Ford, & Buchhorn, both as presented originally by those authors and after reanalyzing their digital reduction files using identical disk-fitting procedures. Direct comparison is made of profile details for 292 galaxies observed in common. Although some differences occur, good agreement is found, proving that the two data sets can be used in combination with only minor accommodation of those differences. The compilation of optical properties presented here is optimized for use in applications of the Tully-Fisher relation as a secondary distance indicator in studies of the local peculiar velocity field

The Motions of Clusters of Galaxies and the Dipoles of the Peculiar Velocity Field

In preceding papers of this series, TF relations for galaxies in 24 clusters with radial velocities between 1000 and 9200 km s-1 (SCI sample) were obtained, a Tully-Fisher (TF) template relation was constructed, and mean offsets of each cluster with respect to the template were obtained. Here, an estimate of the line-of-sight peculiar velocities of the clusters and their associated errors are given. It is found that cluster peculiar velocities in the cosmic microwave background reference frame do not exceed 600 km s-1 and that their distribution has a line-of-sight dispersion of 300 km s-1, suggesting a more quiescent cluster peculiar velocity field than previously reported. When measured in a reference frame in which the Local Group is at rest, the set of clusters at cz \u3e 3000 km s-1 exhibits a dipole moment in agreement with that of the CMB, both in amplitude and apex direction. It is estimated that the bulk flow of a sphere of 6000 km s-1 radius in the CMB reference frame is between 140 and 320 km s-1

Did humans cause the Late Pleistocene-Early Holocene mammalian extinctions in South America in a context of shrinking open areas?

The last important –and possibly the most spectacular– turnover in South American mammal history occurred around the Pleistocene-Holocene boundary, when 100% of megamammal species and about 80% of large mammal species became extinct. In this paper, we consider as “megamammals” those with body mass over 1,000 kg, and “large mammals” those over 44 kg. With the exception of a few smaller mammals, no other animal or plant disappeared. Consequently, this extinction event was distinct from mass extinctions.Facultad de Ciencias Naturales y Muse

A Test of the Lauer-Postman Bulk Flow

We use Tully-Fisher distances for a sample of field late spiral galaxies to test the Lauer & Postman result suggestive of a bulk flow with respect to the cosmic microwave background reference frame, of amplitude of +689 km s-1 in the direction l = 343°, b = +52°. A total of 432 galaxies are used, subdivided between two cones, of 30° semiaperture each and pointed toward the apex and antapex of the LP motion, respectively. The peculiar velocities in the two data sets are inconsistent with a bulk flow of the amplitude claimed by Lauer & Postman. When combined in opposition, the peculiar velocity medians in shells of constant redshift width are never larger than half the amplitude of the Lauer & Postman bulk flow. Out to 5000 km s-1 the median bulk velocity in the Lauer & Postman apex-antapex cones is about 200 km s-1 or less, dropping to a value indistinguishable from zero beyond that distance. It can be excluded that field spiral galaxies within 8000 km s-1 partake of a bulk flow of the amplitude and direction reported by Lauer & Postman

An estimate of \Omega_m without priors

Using mean relative peculiar velocity measurements for pairs of galaxies, we estimate the cosmological density parameter $\Omega_m$ and the amplitude of density fluctuations $\sigma_8$. Our results suggest that our statistic is a robust and reproducible measure of the mean pairwise velocity and thereby the $\Omega_m$ parameter. We get $\Omega_m = 0.30^{+0.17}_{-0.07}$ and $\sigma_8 = 1.13^{+0.22}_{-0.23}$. These estimates do not depend on prior assumptions on the adiabaticity of the initial density fluctuations, the ionization history, or the values of other cosmological parameters.Comment: 12 pages, 4 figures, slight changes to reflect published versio