Intrinsic qualities of primate bones as predictors of skeletal element representation in modern and fossil carnivore feeding assemblages

Plio-Pleistocene faunal assemblages from Swartkrans Cave (South Africa) preserve large numbers of primate remains. Brain, C.K., 1981. The Hunters or the Hunted? An Introduction to African Cave Taphonomy. University of Chicago Press, Chicago suggested that these primate subassemblages might have resulted from a focus by carnivores on primate predation and bone accumulation. Brain's hypothesis prompted us to investigate, in a previous study, this taphonomic issue as it relates to density-mediated destruction of primate bones (J. Archaeol. Sci. 29, 2002, 883). Here we extend our investigation of Brain's hypothesis by examining additional intrinsic qualities of baboon bones and their role as mediators of skeletal element representation in carnivore-created assemblages. Using three modern adult baboon skeletons, we collected data on four intrinsic bone qualities (bulk bone mineral density, maximum length, volume, and cross-sectional area) for approximately 81 bones per baboon skeleton. We investigated the relationship between these intrinsic bone qualities and a measure of skeletal part representation (the percentage minimum animal unit) for baboon bones in carnivore refuse and scat assemblages. Refuse assemblages consist of baboon bones not ingested during ten separate experimental feeding episodes in which individual baboon carcasses were fed to individual captive leopards and a spotted hyena. Scat assemblages consist of those baboon bones recovered in carnivore regurgitations and feces resulting from the feeding episodes. In refuse assemblages, volume (i.e., size) was consistently the best predictor of element representation, while cross-sectional area was the poorest predictor in the leopard refuse assemblage and bulk bone mineral density (i.e., a measure of the proportion of cortical to trabecular bone) was the poorest predictor in the hyena refuse assemblage. In light of previous documentation of carnivore-induced density-mediated destruction to bone assemblages, we interpret the current findings as suggestive of the secondary importance of bulk bone mineral density to other intrinsic qualities of skeletal elements (e.g., size, maximum dimension, and average cross-sectional area). It is only when skeletal elements are too large for consumption (e.g., many long bones) that they are fragmented following intra-element patterns of density-mediated carnivore destruction. There appears to be a size threshold beneath which bulk bone mineral density contributes little to mediating carnivore destruction of carcasses. Thus, depending on body size of the predator, body size of the prey, and specific size of the element, bulk bone mineral density may play little or no role of primary importance in mediating the destruction of skeletal elements. We compare patterns in modern comparative assemblages to patterns in primate fossil assemblages from Swartkrans. One of the fossil assemblages, Swartkrans Member 1, Hanging Remnant, most closely approximates a hyena (possibly refuse) assemblage pattern, while the Swartkrans Member 2 assemblage most closely approximates a leopard (possibly scat) assemblage pattern. The Swartkrans Member 1, Lower Bank, assemblage does not closely approximate any of our modern comparative assemblage patterns.     

"Just Another Tool for Online Studies” (JATOS): An Easy Solution for Setup and Management of Web Servers Supporting Online Studies

We present here “Just Another Tool for Online Studies” (JATOS): an open source, cross-platform web application with a graphical user interface (GUI) that greatly simplifies setting up and communicating with a web server to host online studies that are written in JavaScript. JATOS is easy to install in all three major platforms (Microsoft Windows, Mac OS X, and Linux), and seamlessly pairs with a database for secure data storage. It can be installed on a server or locally, allowing researchers to try the application and feasibility of their studies within a browser environment, before engaging in setting up a server. All communication with the JATOS server takes place via a GUI (with no need to use a command line interface), making JATOS an especially accessible tool for researchers without a strong IT background. We describe JATOS’ main features and implementation and provide a detailed tutorial along with example studies to help interested researchers to set up their online studies. JATOS can be found under the Internet address: www.jatos.org.     

Higher Serum Concentrations of N-Terminal Pro-B-Type Natriuretic Peptide Associate with Prevalent Hypertension whereas Lower Associate with Incident Hypertension

BackgroundThe role of the natriuretic peptides (NPs) in hypertension is complex. Thus, a higher blood NP concentration is a robust marker of pressure-induced cardiac damage in patients with hypertension, whereas genetically elevated NP concentrations are associated with a reduced risk of hypertension and overweight individuals presumably at high risk of hypertension have lower NP concentrations.ObjectiveTo investigate the associations between serum N-terminal pro-B-type natriuretic peptide (NT-proBNP), used as a surrogate marker for active BNP, and prevalent as well as 5-year incident hypertension in a Danish general population sample.MethodsCross-sectional and prospective population-based study.ResultsAt baseline, among 5,307 participants (51.3% women, mean age 46.0±7.9 years) with a complete set of data, we recorded 1,979 cases with prevalent hypertension (PHT). Among 2,389 normotensive participants at baseline with a complete set of data, we recorded 324 cases with incident hypertension (IHT) on follow-up 5 years later. In models adjusted for age, sex, lifestyle, social, dietary, anthropometric, pulmonic, lipid, metabolic and renal risk factors, as well as heart rate and baseline blood pressure (only incident model), one standard deviation increase in baseline log-transformed NT-proBNP concentrations was on one side associated with a 21% higher risk of PHT (odds ratio [OR]: 1.21 [95% confidence interval (CI): 1.13-1.30], P<0.001), and on the other side with a 14% lower risk of IHT (OR: 0.86 [95%CI:0.76-0.98], P = 0.020).ConclusionsHigher serum concentrations of NT-proBNP associate with PHT whereas lower concentrations associate with IHT. This suggests that a lower amount of circulating BNP, resulting in diminished vasodilation and natriuresis, could be involved in the pathogenesis of hypertension in its early stages.