@misc{KlieglRolfsLaubrocketal.2009,
  author    = {Kliegl, Reinhold and Rolfs, Martin and Laubrock, Jochen and Engbert, Ralf},
  title     = {Microsaccadic Modulation of Response Times in Spatial Attention Tasks},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-57098},
  year      = {2009},
  abstract  = {Covert shifts of attention are usually reflected in RT differences between responses to valid and invalid cues in the Posner spatial attention task. Such inferences about covert shifts of attention do not control for microsaccades in the cue target interval. We analyzed the effects of microsaccade orientation on RTs in four conditions, crossing peripheral visual and auditory cues with peripheral visual and auditory discrimination targets. Reaction time was generally faster on trials without microsaccades in the cue-target interval. If microsaccades occurred, the target-location congruency of the last microsaccade in the cuetarget interval interacted in a complex way with cue validity. For valid visual cues, irrespective of whether the discrimination target was visual or auditory, target-congruent microsaccades delayed RT. For invalid cues, target-incongruent microsaccades facilitated RTs for visual target discrimination, but delayed RT for auditory target discrimination. No reliable effects on RT were associated with auditory cues or with the first microsaccade in the cue-target interval. We discuss theoretical implications on the relation about spatial attention and oculomotor processes.},
  language  = {en}
}
@misc{KlieglMassonRichter2009,
  author    = {Kliegl, Reinhold and Masson, Michael E. J. and Richter, Eike M.},
  title     = {A linear mixed model analysis of masked repetition priming},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-57073},
  year      = {2009},
  abstract  = {We examined individual differences in masked repetition priming by re-analyzing item-level response-time (RT) data from three experiments. Using a linear mixed model (LMM) with subjects and items specified as crossed random factors, the originally reported priming and word-frequency effects were recovered. In the same LMM, we estimated parameters describing the distributions of these effects across subjects. Subjects' frequency and priming effects correlated positively with each other and negatively with mean RT. These correlation estimates, however, emerged only with a reciprocal transformation of RT (i.e., -1/RT), justified on the basis of distributional analyses. Different correlations, some with opposite sign, were obtained (1) for untransformed or logarithmic RTs or (2) when correlations were computed using within-subject analyses. We discuss the relevance of the new results for accounts of masked priming, implications of applying RT transformations, and the use of LMMs as a tool for the joint analysis of experimental effects and associated individual differences.},
  language  = {en}
}
@misc{DimigenValsecchiSommeretal.2009,
  author    = {Dimigen, Olaf and Valsecchi, Matteo and Sommer, Werner and Kliegl, Reinhold},
  title     = {Human Microsaccade-Related Visual Brain Responses},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-56923},
  year      = {2009},
  abstract  = {Microsaccades are very small, involuntary flicks in eye position that occur on average once or twice per second during attempted visual fixation. Microsaccades give rise to EMG eye muscle spikes that can distort the spectrum of the scalp EEG and mimic increases in gamma band power. Here we demonstrate that microsaccades are also accompanied by genuine and sizeable cortical activity, manifested in the EEG. In three experiments, high-resolution eye movements were corecorded with the EEG: during sustained fixation of checkerboard and face stimuli and in a standard visual oddball task that required the counting of target stimuli. Results show that microsaccades as small as 0.15° generate a field potential over occipital cortex and midcentral scalp sites 100 -140 ms after movement onset, which resembles the visual lambda response evoked by larger voluntary saccades. This challenges the standard assumption of human brain imaging studies that saccade-related brain activity is precluded by fixation, even when fully complied with. Instead, additional cortical potentials from microsaccades were present in 86\% of the oddball task trials and of similar amplitude as the visual response to stimulus onset. Furthermore, microsaccade probability varied systematically according to the proportion of target stimuli in the oddball task, causing modulations of late stimulus-locked event-related potential (ERP) components. Microsaccades present an unrecognized source of visual brain signal that is of interest for vision research and may have influenced the data of many ERP and neuroimaging studies.},
  language  = {en}
}
@misc{JeličićFriedrichJeremićetal.2009,
  author    = {Jeličić, Aleksandra and Friedrich, Alwin and Jeremić, Katarina and Siekmeyer, Gerd and Taubert, Andreas},
  title     = {Polymer hydrogel/polybutadiene/iron oxide nanoparticle hybrid actuators for the characterization of NiTi implants},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-48589},
  year      = {2009},
  abstract  = {One of the main issues with the use of nickel titanium alloy (NiTi) implants in cardiovascular implants (stents) is that these devices must be of very high quality in order to avoid subsequent operations due to failing stents. For small stents with diameters below ca. 2 mm, however, stent characterization is not straightforward. One of the main problems is that there are virtually no methods to characterize the interior of the NiTi tubes used for fabrication of these tiny stents. The current paper reports on a robust hybrid actuator for the characterization of NiTi tubes prior to stent fabrication. The method is based on a polymer/hydrogel/magnetic nanoparticle hybrid material and allows for the determination of the inner diameter at virtually all places in the raw NiTi tubes. Knowledge of the inner structure of the raw NiTi tubes is crucial to avoid regions that are not hollow or regions that are likely to fail due to defects inside the raw tube. The actuator enables close contact of a magnetic polymer film with the inner NiTi tube surface. The magnetic signal can be detected from outside and be used for a direct mapping of the tube interior. As a result, it is possible to detect critical regions prior to expensive and slow stent fabrication processes.},
  language  = {en}
}
@misc{HeinkenWinkler2009,
  author    = {Heinken, Thilo and Winkler, Eckart},
  title     = {Non-random dispersal by ants : long-term field data versus model predictions of population spread of a forest herb},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-46482},
  year      = {2009},
  abstract  = {Myrmecochory, i.e. dispersal of seeds by ants towards and around their nests, plays an important role in temperate forests. Yet hardly any study has examined plant population spread over several years and the underlying joint contribution of a hierarchy of dispersal modes and plant demography. We used a seed-sowing approach with three replicates to examine colonization patterns of Melampyrum pratense, an annual myrmecochorous herb, in a mixed Scots pine forest in northeastern Germany. Using a spatially explicit individualbased (SEIB) model population patterns over 4 years were explained by short-distance transport of seeds by small ant species with high nest densities, resulting in random spread. However, plant distributions in the field after another 4 years were clearly deviating from model predictions. Mean annual spread rate increased from 0.9 m to 5.1 m per year, with a clear inhomogeneous component. Obviously, after a lag-phase of several years, non-random seed dispersal by large red wood ants (Formica rufa) was determining the species' spread, thus resulting in stratified dispersal due to interactions with different-sized ant species. Hypotheses on stratified dispersal, on dispersal lag, and on non-random dispersal were verified using an extended SEIB model, by comparison of model outputs with field patterns (individual numbers, population areas, and maximum distances). Dispersal towards red wood ant nests together with seed loss during transport and redistribution around nests were essential features of the model extension. The observed lag-phase in the initiation of non-random, medium-distance transport was probably due to a change of ant behaviour towards a new food source of increasing importance, being a meaningful example for a lag-phase in local plant species invasion. The results demonstrate that field studies should check model predictions wherever possible. Future research will show whether or not the M. pratense-ant system is representative for migration patterns of similar animal dispersal systems after having crossed range edges by long-distance dispersal events.},
  language  = {en}
}
@misc{MeierMeschenmoser2009,
  author    = {Meier, Bernd and Meschenmoser, Helmut},
  title     = {Qualit{\"a}tssicherung in Sch{\"u}lerfirmen : indikatorengest{\"u}tztes Qualit{\"a}tsraster zum Lehren und Lernen in einem arbeitsorientierten Lernarrangement},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-46186},
  year      = {2009},
  abstract  = {Sch{\"u}lerfirmen zeugen von der Innovationsf{\"a}higkeit der Schulen. Sie lassen auf Ver{\"a}nderungen des Unterrichts und des Selbstverst{\"a}ndnisses von Schule und Kollegien schließen, denn sie stehen im Kontrast zum traditionellen Fachunterricht. Ihre Existenz sagt allerdings relativ wenig {\"u}ber die damit verbundene Qualit{\"a}t aus. So ist zu kl{\"a}ren, welche Intentionen mit Qualit{\"a}tssicherung verbunden sind. Dar{\"u}ber hinaus wird ein Qualit{\"a}tsraster mit Indikatoren zur Analyse der Entwicklungsprozesse f{\"u}r Sch{\"u}lerfirmen zur Diskussion gestellt.},
  language  = {de}
}
@misc{MeierMeschenmoser2009,
  author    = {Meier, Bernd and Meschenmoser, Helmut},
  title     = {Sch{\"u}lerfirma Pausenschmaus arbeitet mit Erfolg},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-46177},
  year      = {2009},
  abstract  = {Mit Firma Pausenschmaus auf Erfolgskurs In diesem Material wird die Sch{\"u}lerfirma Pausenschmaus vorgestellt. Die Mitarbeiter der Firma Pausenschmaus sind schon gut vorangekommen. Sie haben mehrere Abteilungen gegr{\"u}ndet und gute Kunden gewonnen.},
  language  = {de}
}
@misc{MeierMeschenmoser2009,
  author    = {Meier, Bernd and Meschenmoser, Helmut},
  title     = {Zwischen Kundenwunsch und didaktischem Konzept : Sch{\"u}lerfirmen als integratives Lernarrangement arbeitsorientierter Bildung},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-46160},
  year      = {2009},
  abstract  = {Sch{\"u}lerfirmen haben im Bereich Arbeitslehre in j{\"u}ngster Zeit an Bedeutung gewonnen. Die Autoren stellen im Basisartikel des vorliegenden Heftes Lernen. Gewinn verschiedene Formen von Sch{\"u}lerfirmen vor und erl{\"a}utern Probleme bei der Sicherung der Lernqualit{\"a}t. Diese beziehen sich einerseits auf die optimale F{\"o}rderung arbeitsrelevanter Basiskompetenzen der Sch{\"u}ler und andererseits auf das Erreichen der curricularen Ziele der Arbeitslehre, insbesondere hinsichtlich der technischen und {\"o}konomischen Bildung sowie der Berufsorientierung. Zur Optimierung sind Lehrplankorrekturen, weitere Erfahrungen mit Sch{\"u}lerfirmen und die Unterst{\"u}tzung der Fachdidaktik notwendig. Wichtig sind zudem eine kollegiale Kooperation und Vernetzung an den Lernorten. Die Verfasser f{\"u}hren dar{\"u}ber hinaus in die Beitr{\"a}ge des vorliegenden Heftes ein.},
  language  = {de}
}
@misc{MeierMeschenmoser2009,
  author    = {Meier, Bernd and Meschenmoser, Helmut},
  title     = {Mal sehen, wie Tabea, Ali und ... in der Sch{\"u}lerfirma arbeiten : Lernen am und mit Modell},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-46153},
  year      = {2009},
  abstract  = {Die in den Materialien thematisierte Sch{\"u}lerfirma Pausenschmaus wurde als Prototyp f{\"u}r Lehr- und Lernzwecke modelliert. Die didaktische Modellvorstellung beruht auf Analysen existierender Sch{\"u}lerfirmen und bezieht sich auf die Forumsbeitr{\"a}ge zur Qualit{\"a}tssicherung in diesem Heft. Das Material gibt einerseits f{\"u}r den Unterricht wie f{\"u}r Lehrerfortbildung einen exemplarischen Orientierungsrahmen zur Gestaltung eigener Sch{\"u}lerfirmen, anderseits ist es Grundlage f{\"u}r komplexe Aufgabenstellungen zur arbeitsorientierten Bildung, wie sie im gesonderten Beitrag am Beispiel eines konkreten unternehmerischen Problems ausgef{\"u}hrt werden. Die Darstellungen im Material sind situativ angelegt, um somit Sch{\"u}lerinnen und Sch{\"u}ler an Prozesse und Strukturen von Unternehmen und damit befassten betrieblichen Funktionen heranzuf{\"u}hren. Das Modellunternehmen hat einen Schwerpunkt im Catering.},
  language  = {de}
}
@misc{VossBlenauWalzetal.2009,
  author    = {Voss, Martin and Blenau, Wolfgang and Walz, Bernd and Baumann, Otto},
  title     = {V-ATPase deactivation in blowfly salivary glands is mediated by protein phosphatase 2C},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-44360},
  year      = {2009},
  abstract  = {The activity of vacuolar H+-ATPase (V-ATPase) in the apical membrane of blowfly (Calliphora vicina) salivary glands is regulated by the neurohormone serotonin (5-HT). 5-HT induces, via protein kinase A, the phosphorylation of V-ATPase subunit C and the assembly of V-ATPase holoenzymes. The protein phosphatase responsible for the dephosphorylation of subunit C and V-ATPase inactivation is not as yet known. We show here that inhibitors of protein phosphatases PP1 and PP2A (tautomycin, ocadaic acid) and PP2B (cyclosporin A, FK-506) do not prevent V-ATPase deactivation and dephosphorylation of subunit C. A decrease in the intracellular Mg2+ level caused by loading secretory cells with EDTA-AM leads to the activation of proton pumping in the absence of 5-HT, prolongs the 5-HT-induced response in proton pumping, and inhibits the dephosphorylation of subunit C. Thus, the deactivation of V-ATPase is most probably mediated by a protein phosphatase that is insensitive to okadaic acid and that requires Mg2+, namely, a member of the PP2C protein family. By molecular biological techniques, we demonstrate the expression of at least two PP2C protein family members in blowfly salivary glands. © 2009 Wiley Periodicals, Inc.},
  language  = {en}
}
@misc{BlenauRotteKrachetal.2009,
  author    = {Blenau, Wolfgang and Rotte, Cathleen and Krach, Christian and Balfanz, Sabine and Baumann, Arnd and Walz, Bernd},
  title     = {Molecular characterization and localization of the first tyramine receptor of the American cockroach (Periplaneta americana)},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-44335},
  year      = {2009},
  abstract  = {The phenolamines octopamine and tyramine control, regulate, and modulate many physiological and behavioral processes in invertebrates. Vertebrates possess only small amounts of both substances, and thus, octopamine and tyramine, together with other biogenic amines, are referred to as "trace amines." Biogenic amines evoke cellular responses by activating G-protein-coupled receptors. We have isolated a complementary DNA (cDNA) that encodes a biogenic amine receptor from the American cockroach Periplaneta americana, viz., Peatyr1, which shares high sequence similarity to members of the invertebrate tyramine-receptor family. The PeaTYR1 receptor was stably expressed in human embryonic kidney (HEK) 293 cells, and its ligand response has been examined. Receptor activation with tyramine reduces adenylyl cyclase activity in a dose-dependent manner (EC50 350 nM). The inhibitory effect of tyramine is abolished by co-incubation with either yohimbine or chlorpromazine. Receptor expression has been investigated by reverse transcription polymerase chain reaction and immunocytochemistry. The mRNA is present in various tissues including brain, salivary glands, midgut, Malpighian tubules, and leg muscles. The effect of tyramine on salivary gland acinar cells has been investigated by intracellular recordings, which have revealed excitatory presynaptic actions of tyramine. This study marks the first comprehensive molecular, pharmacological, and functional characterization of a tyramine receptor in the cockroach.},
  language  = {en}
}
@misc{Wehinger2009,
  author    = {Wehinger, Brunhilde},
  title     = {Mode, Kleidung, Kunst : Rezensionsessay},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-45464},
  year      = {2009},
  abstract  = {rezensierte Werke: Bachmann, Cordula: Kleidung und Geschlecht : Ethnographische Erkundungen einer Alltagspraxis / Cordula Bachmann. - Bielefeld : transcript Verlag, 2008. - 154 S. ISBN 978-3-89942-920-6 Pape, Cora von: Kunstkleider : die Pr{\"a}senz des K{\"o}rpers in textilen Kunst-Objekten des 20. Jahrhunderts / Cora von Pape. - Bielefeld : transcript Verlag, 2008. - 225 S. ISBN 978-3-89942-825-4 Zwei neue Studien widmen sich dem Verh{\"a}ltnis von Kleidung und Geschlecht beziehungsweise Kleidung und K{\"o}rper. Wie Frauen und M{\"a}nner in ihrer allt{\"a}glichen Praxis des ‚Sich-Kleidens' mit den modischen Erscheinungsbildern von M{\"a}nnlichkeit oder Weiblichkeit umgehen, untersucht die Kulturwissenschaftlerin Cordula Bachmann. Sie wertet aktuelle Interviews zum Kleidungsverhalten von Frauen und M{\"a}nnern aus und r{\"u}ckt dabei die Perspektive der Handelnden, die das allt{\"a}gliche ‚Sich-Kleiden' als eine prim{\"a}re soziale Anforderung zu l{\"o}sen haben, ins Zentrum des Interesses. Den aufsehenerregenden k{\"u}nstlerischen Umgang mit Kleidung in Form von textilen Kunstobjekten, die sich mit dem menschlichen K{\"o}rper befassen und der Art und Weise, wie er mittels Kleidung und Textilien repr{\"a}sentiert oder transformiert wird, untersucht die Kunsthistorikerin Cora von Pape. Das allt{\"a}gliche weibliche Chaos des Sich-Ankleidens angesichts der t{\"a}glichen Herausforderung, sich bei der Entscheidung f{\"u}r oder gegen ein Kleid, sich auch f{\"u}r oder gegen eine Frauenrolle entscheiden zu m{\"u}ssen, das in den von Bachmann ausgewerteten Interviews thematisiert wird, scheint auch in den Performances oder textilen Kunstobjekten vieler von Cordula von Pape vorgestellten K{\"u}nstlerinnen der 2. H{\"a}lfte des 20. Jahrhunderts auf, allerdings k{\"u}nstlerisch-experimentell bearbeitet in eindrucksvollen (Selbst-)Inszenierungen, die der gewaltigen Symbolik des Sich-Ankleidens, der Kleider als K{\"o}rperh{\"u}llen oder Reliquien, die an die Stelle des verschwundenen K{\"o}rpers treten, auf den Grund gehen.},
  language  = {de}
}
@misc{KoseskaZaikinKurthsetal.2009,
  author    = {Koseska, Aneta and Zaikin, Alexey and Kurths, J{\"u}rgen and Garc{\´i}a-Ojalvo, Jordi},
  title     = {Timing cellular decision making under noise via cell-cell communication},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-45260},
  year      = {2009},
  abstract  = {Many cellular processes require decision making mechanisms, which must act reliably even in the unavoidable presence of substantial amounts of noise. However, the multistable genetic switches that underlie most decision-making processes are dominated by fluctuations that can induce random jumps between alternative cellular states. Here we show, via theoretical modeling of a population of noise-driven bistable genetic switches, that reliable timing of decision-making processes can be accomplished for large enough population sizes, as long as cells are globally coupled by chemical means. In the light of these results, we conjecture that cell proliferation, in the presence of cell-cell communication, could provide a mechanism for reliable decision making in the presence of noise, by triggering cellular transitions only when the whole cell population reaches a certain size. In other words , the summation performed by the cell population would average out the noise and reduce its detrimental impact.},
  language  = {en}
}
@misc{SzymanskiJozefczukNikoloskietal.2009,
  author    = {Szymanski, Jedrzej and Jozefczuk, Szymon and Nikoloski, Zoran and Selbig, Joachim and Nikiforova, Victoria and Catchpole, Gareth and Willmitzer, Lothar},
  title     = {Stability of metabolic correlations under changing environmental conditions in Escherichia coli : a systems approach},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-45253},
  year      = {2009},
  abstract  = {Background: Biological systems adapt to changing environments by reorganizing their cellula r and physiological program with metabolites representing one important response level. Different stresses lead to both conserved and specific responses on the metabolite level which should be reflected in the underl ying metabolic network. Methodology/Principal Findings: Starting from experimental data obtained by a GC-MS based high-throughput metabolic profiling technology we here develop an approach that: (1) extracts network representations from metabolic conditiondependent data by using pairwise correlations, (2) determines the sets of stable and condition-dependent correlations based on a combination of statistical significance and homogeneity tests, and (3) can identify metabolites related to the stress response, which goes beyond simple ob servation s about the changes of metabolic concentrations. The approach was tested with Escherichia colias a model organism observed under four different environmental stress conditions (cold stress, heat stress, oxidative stress, lactose diau xie) and control unperturbed conditions. By constructing the stable network component, which displays a scale free topology and small-world characteristics, we demonstrated that: (1) metabolite hubs in this reconstructed correlation networks are significantly enriched for those contained in biochemical networks such as EcoCyc, (2) particular components of the stable network are enriched for functionally related biochemical path ways, and (3) ind ependently of the response scale, based on their importance in the reorganization of the cor relation network a set of metabolites can be identified which represent hypothetical candidates for adjusting to a stress-specific response. Conclusions/Significance: Network-based tools allowed the identification of stress-dependent and general metabolic correlation networks. This correlation-network-ba sed approach does not rely on major changes in concentration to identify metabolites important for st ress adaptation, but rather on the changes in network properties with respect to metabolites. This should represent a useful complementary technique in addition to more classical approaches.},
  language  = {en}
}
@misc{WienhoeferGermerLindenmaieretal.2009,
  author    = {Wienh{\"o}fer, Jan and Germer, Kai and Lindenmaier, Falk and F{\"a}rber, Arne and Zehe, Erwin},
  title     = {Applied tracers for the observation of subsurface stormflow at the hillslope scale},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-45246},
  year      = {2009},
  abstract  = {Rain fall-runoff response in temperate humid headwater catchments is mainly controlled by hydrolo gical processes at the hillslope scale. Applied tracer experiments with fluore scent dye and salt tracers are well known tools in groundwater studies at the large scale and vadose zone studies at the plot scale, where they provide a means to characterise subsurface flow. We extend this approach to the hillslope scale to investigate saturated and unsaturated flow path s concertedly at a forested hill slope in the Austrian Alps. Dye staining experiments at the plot scale revealed that crack s and soil pipe s function as preferential flow path s in the fine-textured soils of the study area, and these preferenti al flow structures were active in fast subsurface transport of tracers at the hillslope scale. Breakthrough curves obtained under steady flow conditions could be fitted well to a one-dimensional convection-dispersion model. Under natural rain fall a positive correlation of tracer concentrations to the transient flows was observed. The results of this study demon strate qualitative and quantitative effects of preferential flow feature s on subsurface stormflow in a temperate humid headwater catchment. It turn s out that , at the hill slope scale, the interaction s of structures and processes are intrinsically complex, which implies that attempts to model such a hillslope satisfactorily require detailed investigation s of effective structures and parameters at the scale of interest.},
  language  = {en}
}
@misc{MellWartenburgerMarschneretal.2009,
  author    = {Mell, Thomas and Wartenburger, Isabell and Marschner, Alexander and Villringer, Arno and Reischies, Friedel M. and Heekeren, Hauke R.},
  title     = {Altered function of ventral striatum during reward-based decision making in old age},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-45235},
  year      = {2009},
  abstract  = {Normal aging is associated with a decline in different cognitive domains and local structural atrophy as well as decreases in dopamine concentration and receptor density. To date, it is largely unknown how these reductions in dopaminergic neurotransmission affect human brain regions responsible for reward-based decision making in older adults. Using a learning criterion in a probabilistic object reversal task, we found a learning stage by age interaction in the dorsolateral prefrontal cortex (dIPFC) during decision making. While young adults recruited the dlPFC in an early stage of learning reward associations, older adults recruited the dlPFC when reward associations had already been learned. Furthermore, we found a reduced change in ventral striatal BOLD signal in older as compared to younger adults in response to high probability rewards. Our data are in line with behavioral evidence that older adults show altered stimulus-reward learning and support the view of an altered fronto-striatal interaction during reward-based decision making in old age, which contributes to prolonged learning of reward associations.},
  language  = {en}
}
@misc{ChildsNikoloskiMayetal.2009,
  author    = {Childs, Liam H. and Nikoloski, Zoran and May, Patrick and Walther, Dirk},
  title     = {Identification and classification of ncRNA molecules using graph properties},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-45192},
  year      = {2009},
  abstract  = {The study of non-coding RNA genes has received increased attention in recent years fuelled by accumulating evidence that larger portions of genomes than previously acknowledged are transcribed into RNA molecules of mostly unknown function, as well as the discovery of novel non-coding RNA types and functional RNA elements. Here, we demonstrate that specific properties of graphs that represent the predicted RNA secondary structure reflect functional information. We introduce a computational algorithm and an associated web-based tool (GraPPLE) for classifying non-coding RNA molecules as functional and, furthermore, into Rfam families based on their graph properties. Unlike sequence-similarity-based methods and covariance models, GraPPLE is demonstrated to be more robust with regard to increasing sequence divergence, and when combined with existing methods, leads to a significant improvement of prediction accuracy. Furthermore, graph properties identified as most informative are shown to provide an understanding as to what particular structural features render RNA molecules functional. Thus, GraPPLE may offer a valuable computational filtering tool to identify potentially interesting RNA molecules among large candidate datasets.},
  language  = {en}
}
@misc{CoxMarisSoetartetal.2009,
  author    = {Cox, Tom and Maris, Tom and Soetart, Karline and Conley, Daniel and van Damme, Stefan and Meire, Patrick and Middelburg, Jack J. and Vos, Matthijs and Struyf, Eric},
  title     = {A macro-tidal freshwater ecosystem recovering from hypereutrophication : the Schelde lease study},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-45180},
  year      = {2009},
  abstract  = {We report a 40 year record of eutrophication and hypoxia on an estuarine ecosystem and its recovery from hypereutrophication. After decades of high inorganic nutrient concentrations and recurring anoxia and hypoxia, we observe a paradoxical increase in chlorophyll-a concentrations with decreasing nutrient inputs. We hypothesise that algal growth was inhibited due to hypereutrophication, either by elevated ammonium concentrations, severe hypoxia or the production of harmful substances in such a reduced environment. We study the dynamics of a simple but realistic mathematical model, incorporating the assumption of algal growth inhibition. It shows a high algal biomass, net oxygen production equilibrium with low ammonia inputs, and a low algal biomass, net oxygen consumption equilibrium with high ammonia inputs. At intermediate ammonia inputs it displays two alternative stable states. Although not intentional, the numerical output of this model corresponds to observations, giving extra support for assumption of algal growth inhibition. Due to potential algal growth inhibition, the recovery of hypereutrophied systems towards a classical eutrophied state, will need reduction of waste loads below certain thresholds and will be accompanied by large fluctuations in oxygen concentrations. We conclude that also flow-through systems, heavily influenced by external forcings which partly mask internal system dynamics, can display multiple stable states.},
  language  = {en}
}
@misc{ZiegeMahlowHennigeSulzetal.2009,
  author    = {Ziege, Madlen and Mahlow, Kristin and Hennige-Sulz, Carmen and Kronmarck, Claudia and Tiedemann, Ralph and Streit, Bruno and Plath, Martin},
  title     = {Audience effects in the Atlantic molly (Poecilia mexicana) : prudent male mate choice in response to perceived sperm competition risk?},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-45171},
  year      = {2009},
  abstract  = {Background: Multidirectional interactions in social networks can have a profound effect on mate choice behavior; e.g., Poecilia mexicana males show weaker expression of mating preferences when being observed by a rival. This may be an adaptation to reduce sperm competition risk, which arises because commonly preferred female phenotypes will receive attention also from surrounding males, and/or because other males can copy the focal male's mate choice. Do P. mexicana males indeed respond to perceived sperm competition risk? We gave males a choice between two females and repeated the tests under one of the following conditions: (1) an empty transparent cylinder was presented (control); (2) another ("audience") male inside the cylinder observed the focal male throughout the 2nd part, or (3) the audience male was presented only before the tests, but could not eavesdrop during the actual choice tests (non-specific sperm competition risk treatments); (4) the focal male could see a rival male interact sexually with the previously preferred, or (5) with the non-preferred female before the 2nd part of the tests (specific sperm competition risk treatments). Results: The strength of individual male preferences declined slightly also during the control treatment (1). However, this decrease was more than two-fold stronger in audience treatment (2), i.e., with non-specific sperm competition risk including the possibility for visual eavesdropping by the audience male. No audience effect was found in treatments (3) and (5), but a weak effect was also observed when the focal male had seen the previously preferred female sexually interact with a rival male (treatment 4; specific sperm competition risk). Conclusion: When comparing the two 'non-specific sperm competition risk' treatments, a very strong effect was found only when the audience male could actually observe the focal male during mate choice [treatment (2)]. This suggests that focal males indeed attempt to conceal their mating preferences so as to prevent surrounding males from copying their mate choice. When there is no potential for eavesdropping [treatment (3)], non-specific specific sperm competition risk seems to play a minor or no role. Our results also show that P. mexicana males tend to share their mating effort more equally among females when the resource value of their previously preferred mate decreases after mating with a rival male (perceived specific sperm competition risk), but this effect is comparatively weak.},
  language  = {en}
}
@misc{GaertnerSteinfathAndorfetal.2009,
  author    = {G{\"a}rtner, Tanja and Steinfath, Matthias and Andorf, Sandra and Lisec, Jan and Meyer, Rhonda C. and Altmann, Thomas and Willmitzer, Lothar and Selbig, Joachim},
  title     = {Improved heterosis prediction by combining information on DNA- and metabolic markers},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-45132},
  year      = {2009},
  abstract  = {Background: Hybrids represent a cornerstone in the success story of breeding programs. The fundamental principle underlying this success is the phenomenon of hybrid vigour, or heterosis. It describes an advantage of the offspring as compared to the two parental lines with respect to parameters such as growth and resistance against abiotic or biotic stress. Dominance, overdominance or epistasis based models are commonly used explanations. Conclusion/Significance: The heterosis level is clearly a function of the combination of the parents used for offspring production. This results in a major challenge for plant breeders, as usually several thousand combinations of parents have to be tested for identifying the best combinations. Thus, any approach to reliably predict heterosis levels based on properties of the parental lines would be highly beneficial for plant breeding. Methodology/Principal Findings: Recently, genetic data have been used to predict heterosis. Here we show that a combination of parental genetic and metabolic markers, identified via feature selection and minimum-description-length based regression methods, significantly improves the prediction of biomass heterosis in resulting offspring. These findings will help furthering our understanding of the molecular basis of heterosis, revealing, for instance, the presence of nonlinear genotype-phenotype relationships. In addition, we describe a possible approach for accelerated selection in plant breeding.},
  language  = {en}
}