@misc{EngbertKliegl2003, author = {Engbert, Ralf and Kliegl, Reinhold}, title = {The game of word skipping: Who are the competitors?}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-56899}, year = {2003}, abstract = {Computational models such as E-Z Reader and SWIFT are ideal theoretical tools to test quantitatively our current understanding of eye-movement control in reading. Here we present a mathematical analysis of word skipping in the E-Z Reader model by semianalytic methods, to highlight the differences in current modeling approaches. In E-Z Reader, the word identification system must outperform the oculomotor system to induce word skipping. In SWIFT, there is competition among words to be selected as a saccade target. We conclude that it is the question of competitors in the "game" of word skipping that must be solved in eye movement research.}, language = {en} } @misc{ReichLoehmannsroebenSchael2003, author = {Reich, Oliver and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Schael, Frank}, title = {Optical sensing with photon density waves: investigation of model media}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-13147}, year = {2003}, abstract = {Investigations with frequency domain photon density waves allow elucidation of absorption and scattering properties of turbid media. The temporal and spatial propagation of intensity modulated light with frequencies up to more than 1 GHz can be described by the P1 approximation to the Boltzmann transport equation. In this study, we establish requirements for the appropriate choice of turbid model media and characterize mixtures of isosulfan blue as absorber and polystyrene beads as scatterer. For these model media, the independent determination of absorption and reduced scattering coefficients over large absorber and scatterer concentration ranges is demonstrated with a frequency domain photon density wave spectrometer employing intensity and phase measurements at various modulation frequencies.}, language = {en} } @misc{BlenauGrohmannErberetal.2003, author = {Blenau, Wolfgang and Grohmann, Lore and Erber, Joachim and Ebert, Paul R. and Str{\"u}nker, Timo and Baumann, Arnd}, title = {Molecular and functional characterization of an octopamine receptor from honeybee (Apis mellifera) brain}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-44293}, year = {2003}, abstract = {Biogenic amines and their receptors regulate and modulate many physiological and behavioural processes in animals. In vertebrates, octopamine is only found in trace amounts and its function as a true neurotransmitter is unclear. In protostomes, however, octopamine can act as neurotransmitter, neuromodulator and neurohormone. In the honeybee, octopamine acts as a neuromodulator and is involved in learning and memory formation. The identification of potential octopamine receptors is decisive for an understanding of the cellular pathways involved in mediating the effects of octopamine. Here we report the cloning and functional characterization of the first octopamine receptor from the honeybee, Apis mellifera . The gene was isolated from a brain-specific cDNA library. It encodes a protein most closely related to octopamine receptors from Drosophila melanogaster and Lymnea stagnalis . Signalling properties of the cloned receptor were studied in transiently transfected human embryonic kidney (HEK) 293 cells. Nanomolar to micromolar concentrations of octopamine induced oscillatory increases in the intracellular Ca2+ concentration. In contrast to octopamine, tyramine only elicited Ca2+ responses at micromolar concentrations. The gene is abundantly expressed in many somata of the honeybee brain, suggesting that this octopamine receptor is involved in the processing of sensory inputs, antennal motor outputs and higher-order brain functions.}, language = {en} } @misc{KlieglEngbert2003, author = {Kliegl, Reinhold and Engbert, Ralf}, title = {How tight is the link between lexical processing and saccade programs?}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-56919}, year = {2003}, abstract = {We question the assumption of serial attention shifts and the assumption that saccade programs are initiated or canceled only after stage one of word identification. Evidence: (1) Fixation durations prior to skipped words are not consistently higher compared to those prior to nonskipped words. (2) Attentional modulation of microsaccade rate might occur after early visual processing. Saccades are probably triggered by attentional selection.}, language = {en} } @misc{Tristram2003, author = {Tristram, Hildegard L. C.}, title = {Diglossia in Anglo-Saxon England, or what was spoken Old English like?}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-6975}, year = {2003}, abstract = {This paper argues that the texts surviving from the Old English period do not reflect the spoken language of the bulk of the population under Anglo-Saxon elite domination. While the Old English written documents suggest that the language was kept remarkably unchanged, i.e. was strongly monitored during the long OE period (some 500 years!), the spoken and "real Old English" is likely to have been very different and much more of the type of Middle English than the written texts. "Real Old Engish", i.e. of course only appeared in writing after the Norman Conquest. Middle English is therefore claimed to have begun with the 'late British' speaking shifters to Old English. The shift patterns must have differed in the various part of the island of Britain, as the shifters became exposed to further language contact with the Old Norse adstrate in the Danelaw areas and the Norman superstrate particularly in the South East, the South West having been least exposed to language contact after the original shift from 'Late British' to Old English. This explains why the North was historically the most innovative zone. This also explains the conservatism of the present day dialects in the South West. It is high time that historical linguists acknowledge the arcane character of the Old English written texts.}, subject = {Anglistik}, language = {en} } @misc{BillardAnsoborloAppersonetal.2003, author = {Billard, Isabelle and Ansoborlo, Eric and Apperson, Kathleen and Arpigny, Sylvie and Azenha, M. Emilia and Birch, David and Bros, Pascal and Burrows, Hugh D. and Choppin, Gregory and Kumke, Michael Uwe}, title = {Aqueous solutions of Uranium(VI) as studied by time-resolved emission spectroscopy : a Round-Robin Test}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-12318}, year = {2003}, abstract = {Results of an inter-laboratory round-robin study of the application of time-resolved emission spectroscopy (TRES) to the speciation of uranium(VI) in aqueous media are presented. The round-robin study involved 13 independent laboratories, using various instrumentation and data analysis methods. Samples were prepared based on appropriate speciation diagrams and, in general, were found to be chemically stable for at least six months. Four different types of aqueous uranyl solutions were studied: (1) acidic medium where UO22+aq is the single emitting species, (2) uranyl in the presence of fluoride ions, (3) uranyl in the presence of sulfate ions, and (4) uranyl in aqueous solutions at different pH, promoting the formation of hydrolyzed species. Results between the laboratories are compared in terms of the number of decay components, luminescence lifetimes, and spectral band positions. The successes and limitations of TRES in uranyl analysis and speciation in aqueous solutions are discussed.}, language = {en} } @misc{BlenauMustardHamiltonetal.2003, author = {Blenau, Wolfgang and Mustard, Julie A. and Hamilton, Ingrid S. and Ward, Vernon K. and Ebert, Paul R. and Mercer, Alison R.}, title = {Analysis of two D1-like dopamine receptors from the honey bee Apis mellifera reveals agonist-independent activity}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-44378}, year = {2003}, abstract = {Dopamine is found in many invertebrate organisms, including insects, however, the mechanisms through which this amine operates remain unclear. We have expressed two dopamine receptors cloned from honey bee (AmDOP1 and AmDOP2) in insect cells (Spodoptera frugiperda), and compared their pharmacology directly using production of cAMP as a functional assay. In each assay, AmDOP1 receptors required lower concentrations of dopamine and 6,7-ADTN for maximal activation than AmDOP2 receptors. Conversely, butaclamol and cis(Z)-flupentixol were more potent at blocking the cAMP response mediated through AmDOP2 than AmDOP1 receptors. Expression of AmDOP1, but not AmDOP2, receptors significantly increased levels of cAMP even in the absence of ligand. This constitutive activity was blocked by cis(Z)-flupentixol. This work provides the first evidence of a constitutively activated dopamine receptor in invertebrates and suggests that although AmDOP1 and AmDOP2 share much less homology than their vertebrate counterparts, they display a number of functional parallels with the mammalian D1-like dopamine receptors.}, language = {en} } @misc{BlenauBaumann2003, author = {Blenau, Wolfgang and Baumann, Arnd}, title = {Aminergic signal transduction in invertebrates : focus on tyramine and octopamine receptors}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-44271}, year = {2003}, abstract = {Electro-chemical signal transduction is the basis of communication between n eurons and their target cells. An important group of neuroactive substances that are released by action potentials from neurons are the biogenic amines. These a re small organic molecules that bind to specific receptors located in the target cell membrane. Once activated these receptors cause changes in the intracellula r concentration of second messengers, i.e. cyclic nucleotides, phosphoinositides , or Ca2+, leading to slow but long-lasting cellular responses. Biochemical, pha rmacological, physiological, and molecular biological approaches have unequivoca lly shown that biogenic amines are important regulators of cellular function in both vertebrates and invertebrates. In this review, we will concentrate on the p roperties of two biogenic amines and their receptors that were originally identi fied in invertebrates: tyramine and octopamine. }, language = {en} }