19,270 research outputs found

    Calling Dick Tracy! Or, Cellphone Use, Progress, and a Racial Paradigm

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    The hero and phone-watch from Dick Tracy are evoked regularly in news and studies of cellphone use. This paper argues that the racial paradigm of White law enforcer and Dark law-breaker in the comic strip resonates in contemporary evocations and in discussions of cellphone use and crime. Representations of mobile communication and racialized criminality in Dick Tracy were inspired by the 1930s “war on crime” that intersected with wireless innovations and with lynching. This paper interprets that repeated evocation of the comic strip is a “perverse nostalgia” for an old-fashioned form of law and order premised on racialized violence and viewing

    The magnetic activity, winds and planets of young, cool stars

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    This thesis uses spectropolarimetry to observationally investigate the properties of dynamos and winds of young cool stars, and search for young planets. The techniques of Doppler Imaging and Zeeman Doppler Imaging were used to reconstruct the surface brightness and large-scale magnetic field morphologies of four low-mass weak-line T Tauri stars. The first sample consists of two solar mass stars of different ages, V1095 Sco (1 Myrs) and TWA 9A (10 Myrs). The second sample analysed consists of two 10 Myr old, M-type stars, TWA 25 (0.7 M⊙) and TWA 7 (0.4 M⊙). Taken together, the reconstructed brightness maps of these young cool stars show a wide variety in their morphologies, as do the reconstructed large-scale magnetic fields. These findings are in agreement with the results of the wider Magnetic Topologies of Young Stars and the Survival of close-in giant Exoplanets (MaTYSSE) large programme, of which this thesis is a part. The variations in radial velocity are examined for all four stars, using the brightness information where available to filter out activity jitter, improving the detection limits for close-in giant planets around these stars. In addition to this investigation of pre-main sequence stellar dynamos and young planetary systems, a time series of magnetic field observations of the planet-hosting young star T Boötis spanning more than half a decade - the longest to date - is used to infer changes in the stellar wind, and the resulting potential impacts on the orbiting planet. In overall terms, this thesis demonstrates that spectropolarimetry is a valuable tool for understanding the magnetic dynamos of young cool stars, modelling stellar winds, and for searching for planets in the presence of stellar activity. In future, spectropolarimetry used as part of radial velocity surveys can advance our understanding of the early evolution of cool stars and their planetary systems

    Subject searching requirements : the HILT II experience

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    The HILT Phase II project aimed to develop a pilot terminologies server with a view to improving cross-sectoral information retrieval. In order to inform this process, it was first necessary to examine how a representative group of users approached a range of information-related tasks. This paper focuses on exploratory interviews conducted to investigate the proposed ideal and actual strategies of a group of 30 users in relation to eight separate information tasks. In addition, users were asked to give examples of search terms they may employ and to describe how they would formulate search queries in each scenario. The interview process undertaken and the results compiled are outlined, and associated implications for the development of a pilot terminologies server are discussed

    GDL: a model infrastructure for a regional digital library

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    This brief article describes the early days of the Glasgow Digital Library (GDL), when it was a cross-sectoral and city-wide collaborative initiative involving Strathclyde, Glasgow and Caledonian Universities, as well as Glasgow City Libraries and Archives and the Glasgow Colleges Group

    An X-ray absorption spectroscopic study at the mercury LIII edge on phenylmercury(II) oxygen species

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    The X-ray absorption spectra of the reference and model compounds HgCl2, PhHgCl, PhHgOAc and [(PhHg)2OH][BF4].H2O have been analysed in both the XANES and EXAFS regions, and the technique was extended to determine the structures of (PhHg)2O, PhHgOH, and the basic salts PhHgOH.PhHgNO3 and PhHgOH.(PhHg)2SO4, which were previously structurally uncharacterised. Results indicate that (PhHg)2O is a molecular species with Hg-O-Hg 135°, while PhHgOH contains the [(PhHg)2OH]+ cation and is better formulated as [(PhHg)2OH]OH. The same cation is also featured in the two basic salts. Electrospray mass spectral studies of PhHgOH in aqueous solutions show that [PhHgOH2]+, [(PhHg)2OH]+ and [(PhHg)3O]+ co-exist in solution in a pH-dependent equilibrium

    Investigating the role of the land surface in explaining the interannual variation of the net radiation balance over the Western Sahara and sub-Sahara

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    The status of the data sets is discussed. Progress was made in both data analysis and modeling areas. The atmospheric and land surface contributions to the net radiation budget over the Sahara-Sahel region is being decoupled. The interannual variability of these two processes was investigated and this variability related to seasonal rainfall fluctuations. A modified Barnes objective analysis scheme was developed which uses an eliptic scan pattern and a 3-pass iteration of the difference fields

    Biogenesis of cytochrome c1

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    The biogenesis of cytochrome c1 involves a number of steps including: synthesis as a precursor with a bipartite signal sequence, transfer across the outer and inner mitochondrial membranes, removal of the first part of the presequence in the matrix, reexport to the outer surface of the inner membrane, covalent addition of heme, and removal of the remainder of the presequence. In this report we have focused on the steps of heme addition, catalyzed by cytochrome c1 heme lyase, and of proteolytic processing during cytochrome c1 import into mitochondria. Following translocation from the matrix side to the intermembrane-space side of the inner membrane, apocytochrome c1 forms a complex with cytochrome c1 heme lyase, and then holocytochrome c1 formation occurs. Holocytochrome c1 formation can also be observed in detergent-solubilized preparations of mitochondria, but only after apocytochrome c1 has first interacted with cytochrome c1 heme lyase to produce this complex. Heme linkage takes place on the intermembrane- space side of the inner mitochondrial membrane and is dependent on NADH plus a cytosolic cofactor that can be replaced by flavin nucleotides. NADH and FMN appear to be necessary for reduction of heme prior to its linkage to apocytochrome c1. The second proteolytic processing of cytochrome c1 does not take place unless the covalent linkage of heme to apocytochrome c1 precedes it. On the other hand, the cytochrome c1 heme lyase reaction itself does not require that processing of the cytochrome c1 precursor to intermediate size cytochrome c1 takes place first. In conclusion, cytochrome c1 heme lyase catalyzes an essential step in the import pathway of cytochrome c1, but it is not involved in the transmembrane movement of the precursor polypeptide. This is in contrast to the case for cytochrome c in which heme addition is coupled to its transport directly across the outer membrane into the intermembrane space
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