Likelihood estimators for multivariate extremes

The main approach to inference for multivariate extremes consists in approximating the joint upper tail of the observations by a parametric family arising in the limit for extreme events. The latter may be expressed in terms of componentwise maxima, high threshold exceedances or point processes, yielding different but related asymptotic characterizations and estimators. The present paper clarifies the connections between the main likelihood estimators, and assesses their practical performance. We investigate their ability to estimate the extremal dependence structure and to predict future extremes, using exact calculations and simulation, in the case of the logistic model

The Making of a MOOC: Reflections from the Journey!

The Making of a MOOC': Any relevance to "normal" learning and teaching? MOOCs (massive open online courses) are a hugely topical area of educational policy and practice. The University of Glasgow is developing two new courses in partnership with FutureLearn, a free, open, online platform for courses from multiple UK and international universities. The university will initially offer two courses, one from the School of Medicine and one from the School of Law, beginning in May/June 2014.'Cancer in the 21st Century: The Genomic Revolution' has been developed by the School of Medicine in collaboration with the Institute of Cancer Sciences. In this presentation we will provide an introduction to MOOCs and reflect on our own experiences in the development of the cancer genetics MOOC over the past year. Specific areas of potential relevance to traditional course design such as student retention, student engagement, peer-assisted learning and peer review will be considered. We will review our approach to course design and discuss how factors such as online accessibility, the size of the student cohort, and the varying levels of background knowledge amongst students have influenced our decision making process. The design of the student surveys for the course and how the data generated will impact our model of sustainability for the MOOC in future academic sessions will also be discussed

Local effects of culverts on habitat features and fish assemblages in Blue Ridge streams

I studied environmental conditions, fish assemblages, and culvert features in 11 headwater streams (Tennessee and Conasauga river drainages) in Cherokee National Forest (Blue Ridge ecoregion), Tennessee, May-August 2008. Culvert-related effects on instream habitat and fish assemblages were measured at 10 stream sites: five sites contained culverts with artificial bottom substrates and five sites contained culverts with natural bottom substrates. On each stream, paired sampling reaches (reach length ~35 times mean reach width, drainage area \u3c11 km 2) were established 50 m upstream and 50 m downstream of the culvert. Reaches downstream of culverts with artificial substrates (compared to upstream reaches; related-samples t test) exhibited greater water depths, lower gravel/sediment depths, and higher percentages of bedrock and boulder substrates (P \u3c 0.10). Reaches downstream of natural substrate culverts (compared to upstream reaches) exhibited faster current velocities (P \u3c 0.10). Fish abundance (predominantly western blacknose dace Rhinichthys obtusus) was consistently higher downstream than upstream (P \u3c 0.10), regardless of the culvert type. In addition, reaches downstream of artificial substrate culverts exhibited reduced species evenness compared to upstream reaches. Mark-recapture experiments on two streams documented fish movements through a natural substrate culvert (similar to those in reference areas); however, movements through a perched pipe culvert were not detected. Data collected i n the present study suggest that culverts had localized effects on instream habitat and fish assemblages, and that certain types of culverts may impede fish dispersal