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

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

The Tully-Fisher Relation and H0

The use of the Tully-Fisher (TF) relation for the determination of H0 relies on the availability of an adequate template TF relation and of reliable primary distances. Here we use a TF template relation with the best available kinematical zero point, obtained from a sample of 24 clusters of galaxies extending to cz ~ 9000 km s-1, and the most recent set of Cepheid distances for galaxies fit for TF use. The combination of these two ingredients yields H0 = 69 ± 5 km s-1 Mpc-1. The approach is significantly more accurate than the more common application with single cluster (e.g., Virgo, Coma) samples

Peculiar Velocity Dipoles of Field Galaxies

The Tully-Fisher (TF) relation is applied to obtain peculiar velocities of field spiral galaxies and to calculate dipoles of the peculiar velocity field to cz8000 km s-1. The field galaxy sample is spatially coextensive with and completely independent of a cluster sample, for which dipole characteristics are given in a separate paper. Dipoles of the peculiar velocity field are obtained separately by applying (1) an inverse version of the TF relation and selecting galaxies by redshift windowing and (2) a direct TF relation, with velocities corrected for the inhomogeneous Malmquist bias and windowing galaxies by TF distance. The two determinations agree, as they do with the cluster sample. When measured in a reference frame in which the Local Group is at rest, the dipole moment of field galaxies farther than ~4000 km s-1 is in substantial agreement, both in amplitude and direction, with that exhibited by the cosmic microwave background radiation field