Elliptic U(2) quantum group and elliptic hypergeometric series

We investigate an elliptic quantum group introduced by Felder and Varchenko, which is constructed from the $R$-matrix of the Andrews-Baxter-Forrester model, containing both spectral and dynamical parameter. We explicitly compute the matrix elements of certain corepresentations and obtain orthogonality relations for these elements. Using dynamical representations these orthogonality relations give discrete bi-orthogonality relations for terminating very-well-poised balanced elliptic hypergeometric series, previously obtained by Frenkel and Turaev and by Spiridonov and Zhedanov in different contexts.Comment: 20 page

Hot packets:a systematic evaluation of the effect of temperature on low power wireless transceivers

Temperature is known to have a significant effect on the performance of radio transceivers: the higher the temperature, the lower the quality of links. Analysing this effect is particularly important in sensor networks because several applications are exposed to harsh environmental conditions. Daily or hourly changes in temperature can dramatically reduce the throughput, increase the delay, or even lead to network partitions. A few studies have quantified the impact of temperature on low-power wireless links, but only for a limited temperature range and on a single radio transceiver. Building on top of these preliminary observations, we design a low-cost experimental infrastructure to vary the onboard temperature of sensor nodes in a repeatable fashion, and we study systematically the impact of temperature on various sensornet platforms. We show that temperature affects transmitting and receiving nodes differently, and that all platforms follow a similar trend that can be captured in a simple first-order model. This work represents an initial stepping stone aimed at predicting the performance of a network considering the particular temperature profile of a given environment

Biogeochemical data from terrestrial and aquatic ecosystems in a periglacial catchment, West Greenland

Global warming is expected to be most pronounced in the Arctic where permafrost thaw and release of old carbon may provide an important feedback mechanism to the climate system. To better understand and predict climate effects and feedbacks on the cycling of elements within and between ecosystems in northern latitude landscapes, a thorough understanding of the processes related to transport and cycling of elements is required. A fundamental requirement to reach a better process understanding is to have access to high-quality empirical data on chemical concentrations and biotic properties for a wide range of ecosystem domains and functional units (abiotic and biotic pools). The aim of this study is therefore to make one of the most extensive field data sets from a periglacial catchment readily available that can be used both to describe present-day periglacial processes and to improve predictions of the future. Here we present the sampling and analytical methods, field and laboratory equipment and the resulting biogeochemical data from a state-of-the-art whole-ecosystem investigation of the terrestrial and aquatic parts of a lake catchment in the Kangerlussuaq region, West Greenland. This data set allows for the calculation of whole-ecosystem mass balance budgets for a long list of elements, including carbon, nutrients and major and trace metals. The data set is freely available and can be downloaded from PANGAEA: doi: 10.1594/PANGAEA.860961

The poor man’s goldmine? : Career paths in Swedish and Finnish merchant shipping, c. 1840–1950

This article analyses the career paths of Swedish and Finnish sailors from the mid-19th to the mid-20th century. The article shows that, for the most of the men, the seaman’s occupation was just a passing phase before taking up a job on shore, but many of them also created a longlasting and advancing career by going to sea. There was not necessarily, however, a clear distinction between job opportunities at sea and those on shore in those days: men worked both at sea and on shore. We therefore argue that an individual’s advancement in a maritime career was a context-specific socio-economic phenomenon. In Scandinavia, work on board ships was dependent on features that characterized the division of labour in a predominantly agricultural domestic economy on land and emerging industrialization during the turn of the century. Here we present an analysis of the career paths of almost 60,000 men recruited to serve on Swedish and Finnish merchant vessels from the 1840s to late 1940s.peerReviewe