Biogeography and the Cambrian radiation of arachnomorph arthropods

Biogeographic patterns in primarily Cambrian arachnomorph taxa are investigated using a recently constructed phylogenetic hypothesis in order to explore the biogeographic context of the Cambrian radiation. A modified version of Brooks Parsimony Analysis is employed to elucidate patterns of vicariance and geodispersal in taxa from six regions (Laurentia, Baltica, Siberia, Australia, Africa and China). Well resolved vicariance and geodispersal trees are very similar and reconstruct Laurentia and China as sister areas. This close area relationship between Laurentia and China provides extensive evidence for congruent vicariance and range expansion in Cambrian arachnomorphs, while data from trilobites do not show this pattern. Our results imply that cyclic events (such as sea-level change), in conjunction with dispersal ability, may have been more important than tectonic events in generating the biogeographic patterns we observed in Cambrian arachnomorphs. Further, the greater degree of dispersal in various non-trilobite arachnomorph lineages relative to trilobites is correlated with greater extinction resistance across the early-Middle Cambrian boundary

Tumor metastasis to bone

Establishment of skeletal metastasis involves bidirectional interactions between the tumor cell and the cellular elements in the bone microenvironment. A better understanding of the pathophysiology of bone metastasis will be critical in developing the means to prevent bone metastasis or inhibit its progression. The receptor activator of nuclear factor-κB (RANK)/RANK ligand pathway has emerged as the key pathway regulating osteolysis in skeletal metastasis. A number of candidate factors, including the Wnt (wingless int) proteins, endothelin-1, and bone morphogenetic proteins, have been implicated in the establishment of osteoblastic metastasis. The complex nature of tumor-bone microenvironment interactions and the presence of multiple pathways that lead to bone metastasis suggests that simultaneous targeting of these pathways in the metastatic cascade are required for effective treatment. This review discusses current understanding of the pathophysiologic mechanisms that underlie the establishment of bone metastasis and potential molecular therapeutic strategies for prevention and treatment of bone metastasis

Temporal Analysis of Activity Patterns of Editors in Collaborative Mapping Project of OpenStreetMap

In the recent years Wikis have become an attractive platform for social studies of the human behaviour. Containing millions records of edits across the globe, collaborative systems such as Wikipedia have allowed researchers to gain a better understanding of editors participation and their activity patterns. However, contributions made to Geo-wikis_wiki-based collaborative mapping projects_ differ from systems such as Wikipedia in a fundamental way due to spatial dimension of the content that limits the contributors to a set of those who posses local knowledge about a specific area and therefore cross-platform studies and comparisons are required to build a comprehensive image of online open collaboration phenomena. In this work, we study the temporal behavioural pattern of OpenStreetMap editors, a successful example of geo-wiki, for two European capital cities. We categorise different type of temporal patterns and report on the historical trend within a period of 7 years of the project age. We also draw a comparison with the previously observed editing activity patterns of Wikipedia.Comment: Submitte

Oxford Handbook Of American Political Development

Scholars working in or sympathetic to American political development (APD) share a commitment to accurately understanding the history of American politics – and thus they question stylized facts about America’s political evolution. Like other approaches to American politics, APD prizes analytical rigor, data collection, the development and testing of theory, and the generation of provocative hypotheses. Much APD scholarship indeed overlaps with the American politics subfield and its many well developed literatures on specific institutions or processes (for example Congress, judicial politics, or party competition), specific policy domains (welfare policy, immigration), the foundations of (in)equality in American politics (the distribution of wealth and income, race, ethnicity, gender, class, and sexual and gender orientation), public law, and governance and representation. What distinguishes APD is careful, systematic thought about the ways that political processes, civic ideals, the political construction of social divisions, patterns of identity formation, the making and implementation of public policies, contestation over (and via) the Constitution, and other formal and informal institutions and processes evolve over time – and whether (and how) they alter, compromise, or sustain the American liberal democratic regime. APD scholars identify, in short, the histories that constitute American politics. They ask: what familiar or unfamiliar elements of the American past illuminate the present? Are contemporary phenomena that appear new or surprising prefigured in ways that an APD approach can bring to the fore? If a contemporary phenomenon is unprecedented then how might an accurate understanding of the evolution of American politics unlock its significance

APPARATUS FOR THE STUDY OF FISSION-GAS RELEASE FROM NEUTRON-ACTIVATED FUELED GRAPHITE

A simple laboratory apparatus for the study of fissiongas release from neutron-activated fueled graphite was developed. Xenon-133 released from a heated specimen is carried in a helium sweep gas to a charcoal trap, where the accumulated activity is monitored continuously by a scintillation detector, ratemeter, and pen recorder. The maximum specimen temperature (2500 deg F) is achieved in 10 min with an induction heater. All instrumentation is commercially available. Data for several neutron-activated fueled-graphite specimens heated in the range from 800 to 2500 deg F are presented to illustrate the typical results obtained with the apparatus. (auth

Multi-material 3D printed shape memory polymer with tunable melting and glass transition temperature activated by heat or light

Shape memory polymers are attractive smart materials that have many practical applications and academic interest. Three-dimensional (3D) printable shape memory polymers are of great importance for the fabrication of soft robotic devices due to their ability to build complex 3D structures with desired shapes. We present a 3D printable shape memory polymer, with controlled melting and transition temperature, composed of methacrylated polycaprolactone monomers and N-Vinylcaprolactam reactive diluent. Tuning the ratio between the monomers and the diluents resulted in changes in melting and transition temperatures by 20, and 6 °C, respectively. The effect of the diluent addition on the shape memory behavior and mechanical properties was studied, showing above 85% recovery ratio, and above 90% fixity, when the concentration of the diluent was up to 40 wt %. Finally, we demonstrated multi-material printing of a 3D structure that can be activated locally, at two different temperatures, by two different stimuli; direct heating and light irradiation. The remote light activation was enabled by utilizing a coating of Carbon Nano Tubes (CNTs) as an absorbing material, onto sections of the printed objects