@misc{ThielRomanoKurthsetal.2006, author = {Thiel, Marco and Romano, Maria Carmen and Kurths, J{\"u}rgen and Rolfs, Martin}, title = {Twin Surrogates to Test for Complex Synchronisation}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-57231}, year = {2006}, abstract = {We present an approach to generate (multivariate) twin surrogates (TS) based on recurrence properties. This technique generates surrogates which correspond to an independent copy of the underlying system, i. e. they induce a trajectory of the underlying system starting at different initial conditions. We show that these surrogates are well suited to test for complex synchronisation and exemplify this for the paradigmatic system of R¨ossler oscillators. The proposed test enables to assess the statistical relevance of a synchronisation analysis from passive experiments which are typical in natural systems.}, language = {en} } @article{ThielRomanoKurthsetal.2006, author = {Thiel, Marco and Romano, Maria Carmen and Kurths, J{\"u}rgen and Rolfs, Martin and Kliegl, Reinhold}, title = {Twin surrogates to test for complex synchronisation}, doi = {10.1209/epl/i2006-10147-0}, year = {2006}, abstract = {We present an approach to generate (multivariate) twin surrogates (TS) based on recurrence properties. This technique generates surrogates which correspond to an independent copy of the underlying system, i.e. they induce a trajectory of the underlying system starting at different initial conditions. We show that these surrogates are well suited to test for complex synchronisation and exemplify this for the paradigmatic system of Rossler oscillators. The proposed test enables to assess the statistical relevance of a synchronisation analysis from passive experiments which are typical in natural systems}, language = {en} } @article{EvansDeviMaketal.2006, author = {Evans, Nicholas R. and Devi, Lekshmi Sudha and Mak, Chris S. K. and Watkins, Scott E. and Pascu, Sofia I. and K{\"o}hler, Anna and Friend, Richard H. and Williams, Charlotte K. and Holmes, Andrew B.}, title = {Triplet energy back transfer in conjugated polymers with pendant phosphorescent iridium complexes}, issn = {0002-7863}, doi = {10.1021/Ja0584267}, year = {2006}, abstract = {The nature of Dexter triplet energy transfer between bonded systems of a red phosphorescent iridium complex 13 and a conjugated polymer, polyfluorene, has been investigated in electrophosphorescent organic light-emitting diodes. Red- emitting phosphorescent iridium complexes based on the [Ir(btp)2(acac)]fragment (where btp is 2-(2 '- benzo[b]thienyl)pyridinato and acac is acetylacetonate) have been attached either directly (spacerless) or through a - (CH2)(8)-chain (octamethylene-tethered) at the 9-position of a 9-octylfluorene host. The resulting dibromo- functionalized spacerless (8) or octamethylene-tethered (12) fluorene monomers were chain extended by Suzuki polycondensations using the bis(boronate)-terminated fluorene macromonomers 16 in the presence of end-capping chlorobenzene solvent to produce the statistical spacerless (17) and octamethylene-tethered ( 18) copolymers containing an even dispersion of the pendant phosphorescent fragments. The spacerless monomer 12 adopts a face-to-face conformation with a separation of only 3.6 angstrom between the iridium complex and fluorenyl group, as shown by X-ray analysis of a single crystal, and this facilitates intramolecular triplet energy transfer in the spacerless copolymers 17. The photo- and electroluminescence efficiencies of the octamethylene-tethered copolymers 18 are double those of the spacerless copolymers 17, and this is consistent with suppression of the back transfer of triplets from the red phosphorescent iridium complex to the polyfluorene backbone in 18. The incorporation of a -(CH2)(8)- chain between the polymer host and phosphorescent guest is thus an important design principle for achieving higher efficiencies in those electrophosphorescent organic light-emitting diodes for which the triplet energy levels of the host and guest are similar}, language = {en} } @article{LotzKinder2006, author = {Lotz, Anja and Kinder, Annette}, title = {Transfer in artificial grammar learning : the role of repetition information}, issn = {0278-7393}, doi = {10.1037/0278-7393.32.4.707}, year = {2006}, abstract = {In this article, the authors report 2 experiments that investigated the sources of information used in transfer and nontransfer tasks in artificial grammar learning. Multiple regression analyses indicated that 2 types of information about repeating elements were crucial for performance in both tasks: information about the repetition of adjacent elements and information about repetition of elements in the whole item. Similarity of test items to specific training items and chunk information influenced participants' judgments only in nontransfer tasks}, language = {en} } @misc{KlieglNuthmannEngbert2006, author = {Kliegl, Reinhold and Nuthmann, Antje and Engbert, Ralf}, title = {Tracking the Mind During Reading: The Influence of Past, Present, and Future Words on Fixation Durations}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-57225}, year = {2006}, abstract = {Reading requires the orchestration of visual, attentional, language-related, and oculomotor processing constraints. This study replicates previous effects of frequency, predictability, and length of fixated words on fixation durations in natural reading and demonstrates new effects of these variables related to previous and next words. Results are based on fixation durations recorded from 222 persons, each reading 144 sentences. Such evidence for distributed processing of words across fixation durations challenges psycholinguistic immediacy-of-processing and eye-mind assumptions. Most of the time the mind processes several words in parallel at different perceptual and cognitive levels. Eye movements can help to unravel these processes.}, language = {en} } @article{KlieglNuthmannEngbert2006, author = {Kliegl, Reinhold and Nuthmann, Antje and Engbert, Ralf}, title = {Tracking the mind during reading : the influence of past, present, and future words on fixation durations}, issn = {0096-3445}, doi = {10.1037/0096-3445.135.1.12}, year = {2006}, abstract = {Reading requires the orchestration of visual, attentional, language-related, and oculomotor processing constraints. This study replicates previous effects of frequency, predictability, and length of fixated words on fixation durations in natural reading and demonstrates new effects of these variables related to previous and next words. Results are based on fixation durations recorded from 222 persons, each reading 144 sentences. Such evidence for distributed processing of words across fixation durations challenges psycholinguistic immediacy-of-processing and eye- mind assumptions. Most of the time the mind processes several words in parallel at different perceptual and cognitive levels. Eye movements can help to unravel these processes}, language = {en} } @article{NagelWarsinke2006, author = {Nagel, Birgit and Warsinke, Axel}, title = {Towards separation-free electrochemical affinity sensors by using antibodies, aptamers and molecularly imprinted polymers : a review}, doi = {10.1080/00032710600853903}, year = {2006}, language = {en} } @inproceedings{PflegerAlexandersson2006, author = {Pfleger, Norbert and Alexandersson, Jan}, title = {Towards resolving referring expressions by implicitly activated referents in practical dialogue systems}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-10187}, year = {2006}, abstract = {We present an extension to a comprehensive context model that has been successfully employed in a number of practical conversational dialogue systems. The model supports the task of multimodal fusion as well as that of reference resolution in a uniform manner. Our extension consists of integrating implicitly mentioned concepts into the context model and we show how they serve as candidates for reference resolution.}, language = {en} } @article{CouperKuhlenSelting2006, author = {Couper-Kuhlen, Elizabeth and Selting, Margret}, title = {Towards an interactional perspective on prosody and a prosodic perspective on interaction}, year = {2006}, language = {en} } @article{ShenoyKrauledatBlankertzetal.2006, author = {Shenoy, Pradeep and Krauledat, Matthias and Blankertz, Benjamin and Rao, Rajesh P. N. and M{\"u}ller, Klaus-Robert}, title = {Towards adaptive classification for BCI}, doi = {10.1088/1741-2560/3/1/R02}, year = {2006}, abstract = {Non-stationarities are ubiquitous in EEG signals. They are especially apparent in the use of EEG-based brain- computer interfaces (BCIs): (a) in the differences between the initial calibration measurement and the online operation of a BCI, or (b) caused by changes in the subject's brain processes during an experiment (e.g. due to fatigue, change of task involvement, etc). In this paper, we quantify for the first time such systematic evidence of statistical differences in data recorded during offline and online sessions. Furthermore, we propose novel techniques of investigating and visualizing data distributions, which are particularly useful for the analysis of (non-) stationarities. Our study shows that the brain signals used for control can change substantially from the offline calibration sessions to online control, and also within a single session. In addition to this general characterization of the signals, we propose several adaptive classification schemes and study their performance on data recorded during online experiments. An encouraging result of our study is that surprisingly simple adaptive methods in combination with an offline feature selection scheme can significantly increase BCI performance}, language = {en} } @article{WesselSchirdewan2006, author = {Wessel, Niels and Schirdewan, Alexander}, title = {Toward a prediction of sudden death in propofol-related infusion syndrome}, year = {2006}, language = {en} } @article{MontbrioPazoSchmidt2006, author = {Montbrio, Ernest and Pazo, Diego and Schmidt, J{\"u}rgen}, title = {Time delay in the Kuramoto model with bimodal frequency distribution}, series = {Physical review : E, Statistical, nonlinear and soft matter physics}, volume = {74}, journal = {Physical review : E, Statistical, nonlinear and soft matter physics}, publisher = {APS}, address = {College Park}, issn = {1539-3755}, doi = {10.1103/PhysRevE.74.056201}, pages = {5}, year = {2006}, abstract = {We investigate the effects of a time-delayed all-to-all coupling scheme in a large population of oscillators with natural frequencies following a bimodal distribution. The regions of parameter space corresponding to synchronized and incoherent solutions are obtained both numerically and analytically for particular frequency distributions. In particular, we find that bimodality introduces a new time scale that results in a quasiperiodic disposition of the regions of incoherence.}, language = {en} } @article{GermerElsenbeerdeMoraes2006, author = {Germer, Sonja and Elsenbeer, Helmut and de Moraes, Jorge M.}, title = {Throughfall and temporal trends of rainfall redistribution in an open tropical rainforest, south-western Amazonia (Rond{\^o}nia, Brazil)}, issn = {1027-5606}, doi = {10.5194/hess-10-383-2006}, year = {2006}, language = {en} } @article{MohsenKindSobolevetal.2006, author = {Mohsen, Ayman and Kind, Rainer and Sobolev, Stephan Vladimir and Weber, Michael}, title = {Thickness of the lithosphere east of the Dead Sea Transform}, series = {Geophysical journal international}, volume = {167}, journal = {Geophysical journal international}, number = {2}, publisher = {Blackwell}, address = {Oxford}, issn = {0956-540X}, doi = {10.1111/j.1365-246X.2006.03185.x}, pages = {845 -- 852}, year = {2006}, abstract = {We use the S receiver function method to study the lithosphere at the Dead Sea Transform (DST). A temporary network of 22 seismic broad-band stations was operated on both sides of the DST from 2000 to 2001 as part of the DESERT project. We also used data from six additional permanent broad-band seismic stations at the DST and in the surrounding area, that is, in Turkey, Saudi Arabia, Egypt and Cyprus. Clear S-to-P converted phases from the crust-mantle boundary (Moho) and a deeper discontinuity, which we interpret as lithosphere-asthenosphere boundary (LAB) have been observed. The Moho depth (30-38 km) obtained from S receiver functions agrees well with the results from P receiver functions and other geophysical data. We observe thinning of the lithosphere on the eastern side of the DST from 80 km in the north of the Dead Sea to about 65 km at the Gulf of Aqaba. On the western side of the DST, the few data indicate a thin LAB of about 65 km. For comparison, we found a 90-km-thick lithosphere in eastern Turkey and a 160-km-thick lithosphere under the Arabian shield, respectively. These observations support previous suggestions, based on xenolith data, heat flow observations, regional uplift history and geodynamic modelling, that the lithosphere around DST has been significantly thinned in the Late Cenozoic, likely following rifting and spreading of the Red Sea.}, language = {en} } @phdthesis{Bellin2006, author = {Bellin, Ingo}, title = {Thermosensitive Polymer Networks with Two Different Shapes in Memory}, address = {Potsdam}, pages = {117 S. : graph. Darst.}, year = {2006}, language = {en} } @article{OstermeyerMudgeVeitchetal.2006, author = {Ostermeyer, Martin and Mudge, Damien and Veitch, Peter John and Munch, Jesper}, title = {Thermally induced birefringence in Nd : YAG slab lasers}, doi = {10.1364/AO.45.005368}, year = {2006}, abstract = {We study thermally induced birefringence in crystalline Nd:YAG zigzag slab lasers and the associated depolarization losses. The optimum crystallographic orientation of the zigzag slab within the Nd:YAG boule and photoelastic effects in crystalline Nd:YAG slabs are briefly discussed. The depolarization is evaluated using the temperature and stress distributions, calculated using a finite element model, for realistically pumped and cooled slabs of finite dimensions. Jones matrices are then used to calculate the depolarization of the zigzag laser mode. We compare the predictions with measurements of depolarization, and suggest useful criteria for the design of the gain media for such lasers.}, language = {en} } @article{FloresSuarezMellingerWegeneretal.2006, author = {Flores Su{\´a}rez, Rosaura and Mellinger, Axel and Wegener, Michael and Wirges, Werner and Gerhard, Reimund and Singh, Rajeev}, title = {Thermal-pulse tomography of polarization distributions in a cylindrical geometry}, series = {IEEE transactions on dielectrics and electrical insulation}, volume = {13}, journal = {IEEE transactions on dielectrics and electrical insulation}, number = {5}, publisher = {IEEE}, address = {Piscataway}, issn = {1070-9878}, doi = {10.1109/TDEI.2006.258210}, pages = {1030 -- 1035}, year = {2006}, abstract = {Fast, three-dimensional polarization mapping in piezoelectric sensor cables was performed by means of the novel thermal-pulse tomography (TPT) technique with a lateral resolution of 200 mum. The active piezoelectric cable material (a copolymer of polyvinylidene fluoride with trifluoroethylene) was electrically poled with a point-to-cable corona discharge. A focused laser was employed to heat the opaque outer electrode, and the short-circuit current generated by the thermal pulse was used to obtain 3D polarization maps via the scale transformation method. The article describes the TPT technique as a fast non-destructive option for studying cylindrical geometries.}, language = {en} } @article{MellingerWegenerWirgesetal.2006, author = {Mellinger, Axel and Wegener, Michael and Wirges, Werner and Mallepally, Rajendar Reddy and Gerhard, Reimund}, title = {Thermal and temporal stability of ferroelectret films made from cellular polypropylene/air composites}, year = {2006}, abstract = {Ferroelectrets are thin films of polymer foams, exhibiting piezoelectric properties after electrical charging. Ferroelectret foams usually consist of a cellular polymer structure filled with air. Polymer-air composites are elastically soft due to their high air content as well as due to the size and shape of the polymer walls. Their elastically soft composite structure is one essential key for the working principle of ferroelectrets, besides the permanent trapping of electric charges inside the polymer voids. The elastic properties allow large deformations of the electrically charged voids. However, the composite structure can also possibly limit the stability and consequently the range of applications because of, e. g., penetration of gas and liquids accompanied by discharge phenomena or because of a mechanical pre-load which may be required during the application. Here, we discuss various stability aspects related to the piezoelectric properties of polypropylene ferroelectrets. Near and below room temperature, the piezoelectric effect and the stability of the trapped charges are practically independent from humidity during long-time storage in a humid atmosphere or water, or from operating conditions, such as continuous mechanical excitation. Thermal treatment of cellular polypropylene above -10 degrees C leads to a softening of the voided structure which is apparent from the decreasing values of the elastic modulus. This decrease results in an increase of the piezoelectric activity. Heating above 60 degrees C, however, leads to a decrease in piezoelectricity}, language = {en} } @article{MellingerWegenerWirgesetal.2006, author = {Mellinger, Axel and Wegener, Michael and Wirges, Werner and Mallepally, Rajendar Reddy and Gerhard, Reimund}, title = {Thermal and temporal stability of ferroelectret films made from cellular polypropylene/air composites}, year = {2006}, language = {en} } @article{AndrianovSaalfrank2006, author = {Andrianov, Ivan and Saalfrank, Peter}, title = {Theoretical study of vibration-phonon coupling of H adsorbed on a Si(100) surface}, issn = {0021-9606}, doi = {10.1063/1.2161191}, year = {2006}, abstract = {In this paper a perturbation-theory study of vibrational lifetimes for the bending and stretching modes of hydrogen adsorbed on a Si(100) surface is presented. The hydrogen-silicon interaction is treated with a semiempirical bond-order potential. Calculations are performed for H-Si clusters of different sizes. The finite lifetime is due to vibration-phonon coupling, which is assumed to be linear or bilinear in the phonon and nonlinear in the H-Si stretching and bending modes. Lifetimes and vibrational transition rates are evaluated with one- and two-phonon processes taken into account. Temperature effects are also discussed. In agreement with the experiment and previous theoretical treatment it is found that the H-Si (upsilon(s)=1) stretching vibration decays on a nanosecond timescale, whereas for the H-Si (upsilon(b)=1) bending mode a picosecond decay is predicted. For higher-excited vibrations, simple scaling laws are found if the excitation energies are not too large. The relaxation mechanisms for the excited H-Si stretching and the H-Si bending modes are analyzed in detail.}, language = {en} }