University of Nottingham

About: University of Nottingham is a education organization based out in Nottingham, Nottingham, United Kingdom. It is known for research contribution in the topics: Population & Context (language use). The organization has 54772 authors who have published 119600 publications receiving 4227408 citations. The organization is also known as: The University of Nottingham & University College, Nottingham.

Fossil steroids record the appearance of Demospongiae during the Cryogenian period

Abstract: Chemical fossils discovered in sedimentary rocks in Oman provide the earliest evidence for animal life so far discovered. The fossil steroids — 24-isopropylcholestanes characteristic of sponges of the Demospongiae class — date back 635 million years or more to around the time of the Marinoan glaciation, the last of the immense ice ages at the end of the Neoproterozoic. This suggests that the shallow waters in some late Cryogenian ocean basins contained dissolved oxygen in concentrations sufficient to support simple multicellular organisms at least 100 million years before the rapid diversification of bilaterians during the Cambrian explosion. This paper reports chemical fossils characteristic of sponges that date back at least 635 million years ago, constituting the earliest evidence yet found for animal life. The sponges lived during the Marinoan glaciation, the last of the immense ice ages at the end of the Neoproterozoic. No evidence has been found for animal life during the earlier Sturtian glaciation. The Neoproterozoic era (1,000–542 Myr ago) was an era of climatic extremes and biological evolutionary developments culminating in the emergence of animals (Metazoa) and new ecosystems1. Here we show that abundant sedimentary 24-isopropylcholestanes, the hydrocarbon remains of C30 sterols produced by marine demosponges, record the presence of Metazoa in the geological record before the end of the Marinoan glaciation (∼635 Myr ago). These sterane biomarkers are abundant in all formations of the Huqf Supergroup, South Oman Salt Basin, and, based on a new high-precision geochronology2, constitute a continuous 100-Myr-long chemical fossil record of demosponges through the terminal Neoproterozoic and into the Early Cambrian epoch. The demosponge steranes occur in strata that underlie the Marinoan cap carbonate (>635 Myr ago). They currently represent the oldest evidence for animals in the fossil record, and are evidence for animals pre-dating the termination of the Marinoan glaciation. This suggests that shallow shelf waters in some late Cryogenian ocean basins (>635 Myr ago) contained dissolved oxygen in concentrations sufficient to support basal metazoan life at least 100 Myr before the rapid diversification of bilaterians during the Cambrian explosion. Biomarker analysis has yet to reveal any convincing evidence for ancient sponges pre-dating the first globally extensive Neoproterozoic glacial episode (the Sturtian, ∼713 Myr ago in Oman2).

Osteoarthritis, angiogenesis and inflammation

Abstract: Angiogenesis and inflammation are closely integrated processes in osteoarthritis (OA) and may affect disease progression and pain. Inflammation can stimulate angiogenesis, and angiogenesis can facilitate inflammation. Angiogenesis can also promote chondrocyte hypertrophy and endochondral ossification, contributing to radiographic changes in the joint. Inflammation sensitizes nerves, leading to increased pain. Innervation can also accompany vascularization of the articular cartilage, where compressive forces and hypoxia may stimulate these new nerves, causing pain even after inflammation has subsided. Inhibition of inflammation and angiogenesis may provide effective therapeutics for the treatment of OA by improving symptoms and retarding joint damage. This review aims to summarize (i) the evidence that angiogenesis and inflammation play an important role in the pathophysiology of OA and (ii) possible directions for future research into therapeutics that could effectively treat this disease.

A Study of Magnetic Viscosity

Abstract: A general analysis of magnetic viscosity based on activation energy concepts is given. A particular case is considered of the application of the theory to the phenomenon occurring in materials in which bulk magnetization proceeds by the rotational movement of the vectors of single domains, which process, according to a recent theory of Stoner and Wohlfarth, may occur in certain high coercivity alloys. Experiments have been made, using a magnetometer method, with specimens of alnico maintained at various temperatures within the range - 187? c. to 250? c. The results obtained are found to be in good agreement with the theoretical analysis.

The internal structure of language learning motivation and its relationship with language choice and learning effort

Abstract: Language learning motivation is a complex, composite construct, and although past research has identified a number of its key components, the interrelationship of these components has often been subject to debate. Similarly, the exact contribution of the various motivational components to learning behaviors and learning achievement has also been interpreted in different ways. The purpose of this study is to use structural equation modeling to evaluate a proposed theoretical model concerning the internal structure of the second language (L2) motivation complex and its impact on motivated behavior. The basis of the analysis is survey data collected in Hungary from 8,593 pupils, 13 to 14 years old, on two occasions, in 1993 and in 1999. Our main finding is that integrativeness appears to be the single most important factor, subsuming or mediating the effects of all the other responses to questions asked. In light of this finding, we analyze what motivational content this core component might represent in various settings.

Understanding face recognition with an interactive activation model.

Abstract: In this paper we describe how the microstructure of the Bruce & Young (1986) functional model of face recognition may be explored and extended using an interactive activation implementation. A simulation of the recognition of familiarity of individuals is developed which accounts for a range of published findings on the effects of semantic priming, repetition priming and distinctiveness. Finally, we offer some speculative predictions made by the model, and point to an empirical programme of research which it suggests.