Convergence and divergence in the evolution of cat skulls: temporal and spatial patterns of morphological diversity

Background: Studies of biological shape evolution are greatly enhanced when framed in a phylogenetic perspective. Inclusion of fossils amplifies the scope of macroevolutionary research, offers a deep-time perspective on tempo and mode of radiations, and elucidates life-trait changes. We explore the evolution of skull shape in felids (cats) through morphometric analyses of linear variables, phylogenetic comparative methods, and a new cladistic study of saber-toothed cats. Methodology/Principal Findings: A new phylogenetic analysis supports the monophyly of saber-toothed cats (Machairodontinae) exclusive of Felinae and some basal felids, but does not support the monophyly of various sabertoothed tribes and genera. We quantified skull shape variation in 34 extant and 18 extinct species using size-adjusted linear variables. These distinguish taxonomic group membership with high accuracy. Patterns of morphospace occupation are consistent with previous analyses, for example, in showing a size gradient along the primary axis of shape variation and a separation between large and small-medium cats. By combining the new phylogeny with a molecular tree of extant Felinae, we built a chronophylomorphospace (a phylogeny superimposed onto a two-dimensional morphospace through time). The evolutionary history of cats was characterized by two major episodes of morphological divergence, one marking the separation between saber-toothed and modern cats, the other marking the split between large and small-medium cats. Conclusions/Significance: Ancestors of large cats in the ‘Panthera’ lineage tend to occupy, at a much later stage, morphospace regions previously occupied by saber-toothed cats. The latter radiated out into new morphospace regions peripheral to those of extant large cats. The separation between large and small-medium cats was marked by considerable morphologically divergent trajectories early in feline evolution. A chronophylomorphospace has wider applications in reconstructing temporal transitions across two-dimensional trait spaces, can be used in ecophenotypical and functional diversity studies, and may reveal novel patterns of morphospace occupation

The Concept of Bao-Bao-Ba and the Government Supervision and Merchant Management Enterprises in Late Qing China: An Analysis of the Sheng Xuanhuai's taking over of the Hanyang Ironworks in the Year of 1896.

Nuclear magnetic resonance (NMR) is a powerful analytical tool for the study of materials. The utility of NMR is derived from the unique information it provides on the physical and chemical structure of the material being studied. The ability to obtain such information as a function of spatial position within the sample makes magnetic resonance imaging (MRI) potentially an important technique for the NDE of materials [1]. In general, current MRI instrumentation and techniques limit the study of materials to cases where the observed nuclei are in a liquidlike environment. Even so, reports of imaging liquids in solid materials [2,3] and the soft components of materials [4] have appeared. To date there are few examples of MRI applied to the imaging of the solid components of materials [5]

Interactions between TNF and GnRH

Tumour necrosis factor (TNF) ligand members and their associated TNF receptor (TNFR) superfamilies have many diverse physiological roles. TNF is thought to play a critical role in the pathophysiology of a range of diseases including refractory asthma, sepsis, ankylosing spondylitis, lupus, type II diabetes, multiple sclerosis and psoriasis. The recent continued expansion of the novel anti-TNF therapeutic agents (etanercept and infliximab) has seen major improvements in the treatment of some inflammatory-based human diseases including notably rheumatoid arthritis and Crohn’s disease, with other conditions currently being trialled using anti-TNF agents. The cellular signalling machinery used by TNFRs to achieve their many cellular responses are discussed, as is the gonadotrophin-releasing hormone (GnRH) receptor signalling mechanisms. TNF is known to have many actions throughout the body including effects on the hypothalamic-pituitary-adrenal/gonadal axes, with many anti-gonadotrophic effects including a role in the development of endometriosis. These interactions between TNF, GnRH and gonadotrophs are discussed