TY - GEN A1 - Ziege, Madlen A1 - Mahlow, Kristin A1 - Hennige-Sulz, Carmen A1 - Kronmarck, Claudia A1 - Tiedemann, Ralph A1 - Streit, Bruno A1 - Plath, Martin T1 - Audience effects in the Atlantic molly (Poecilia mexicana) : prudent male mate choice in response to perceived sperm competition risk? N2 - 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. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 143 KW - Siamese fighting fish KW - Guppies poecilia-reticulata KW - Betta-splendens KW - Public information KW - Mating preferences Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-45171 ER - TY - JOUR A1 - Zhao, Yan A1 - Herzschuh, Ulrike T1 - Modern pollen representation of source vegetation in the Qaidam Basin and surrounding mountains, north-eastern Tibetan Plateau N2 - We use a data set of 35 surface pollen samples from lake sediments, moss polsters and top soils on the north- eastern Tibetan Plateau to explore the relationship between modern pollen assemblages and contemporary vegetation patterns. The surface pollen transect spanned four vegetation zones--alpine meadow, steppe, steppe desert and desert-- under different climatic/elevational conditions. Relative representation (R (rel)) values and Principal Components Analysis (PCA) were used to determine the relationships between modern pollen and vegetation and regional climate gradients. The results show that the main vegetation zones along the regional and elevational transects can be distinguished by their modern pollen spectra. Relative to Poaceae, a high representation of Artemisia, Nitraria and Chenopodiaceae was found, while Cyperaceae and Gentiana showed values in the middle range, and Ranunculaceae, Asteraceae, Ephedra and Fabaceae had low relative representation values. PCA results indicate a high correlation between the biogeoclimatic zones and annual precipitation and annual temperature and July temperature. The Artemisia/ Chenopodiaceae ratio and the Artemisia/Cyperaceae ratio are useful tools for qualitative and semi-quantitative palaeoenvironmental reconstruction on the north-eastern Tibetan Plateau. Surface lake sediments are found to have different palynomorph spectra from moss cushion and soil samples, reflecting the larger pollen source area in the contemporary vegetation for lakes. Y1 - 2009 UR - http://www.springerlink.com/content/107470 U6 - https://doi.org/10.1007/s00334-008-0201-7 SN - 0939-6314 ER - TY - GEN A1 - Zhang, Gong A1 - Ignatova, Zoya T1 - Generic algorithm to predict the speed of translational elongation : implications for protein biogenesis N2 - Synonymous codon usage and variations in the level of isoaccepting tRNAs exert a powerful selective force on translation fidelity. We have developed an algorithm to evaluate the relative rate of translation which allows large-scale comparisons of the non-uniform translation rate on the protein biogenesis. Using the complete genomes of Escherichia coli and Bacillus subtilis we show that stretches of codons pairing to minor tRNAs form putative sites to locally attenuate translation; thereby the tendency is to cluster in near proximity whereas long contiguous stretches of slow-translating triplets are avoided. The presence of slow-translating segments positively correlates with the protein length irrespective of the protein abundance. The slow-translating clusters are predominantly located down-stream of the domain boundaries presumably to fine-tune translational accuracy with the folding fidelity of multidomain proteins. Translation attenuation patterns at highly structurally and functionally conserved domains are preserved across the species suggesting a concerted selective pressure on the codon selection and species-specific tRNA abundance in these regions. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 132 Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-45007 ER - TY - JOUR A1 - Zhang, Gong A1 - Hubalewska, Magdalena A1 - Ignatova, Zoya T1 - Transient ribosomal attenuation coordinates protein synthesis and co-translational folding N2 - Clustered codons that pair to low-abundance tRNA isoacceptors can form slow-translating regions in the mRNA and cause transient ribosomal arrest. We report that folding efficiency of the Escherichia coli multidomain protein Sufl can be severely perturbed by alterations in ribosome-mediated translational attenuation. Such alterations were achieved by global acceleration of the translation rate with tRNA excess in vitro or by synonymous substitutions to codons with highly abundant tRNAs both in vitro and in vivo. Conversely, the global slow-down of the translation rate modulated by low temperature suppresses the deleterious effect of the altered translational attenuation pattern. We propose that local discontinuous translation temporally separates the translation of segments of the peptide chain and actively coordinates their co-translational folding. Y1 - 2009 UR - http://www.nature.com/nsmb/ U6 - https://doi.org/10.1038/Nsmb.1554 SN - 1545-9985 ER - TY - THES A1 - Zhang, Gong T1 - Transient ribosomal attenuation as a generic mechanism to coordinate protein biosynthesis and biogenesis Y1 - 2009 CY - Potsdam ER - TY - JOUR A1 - Zerbian, Sabine A1 - Downing, Laura A1 - Kügler, Frank T1 - Introduction : tone and intonation from a typological perspective Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/00243841 U6 - https://doi.org/10.1016/j.lingua.2007.10.024 SN - 0024-3841 ER - TY - JOUR A1 - Zeijlstra, Hedde T1 - Hard and soft conditions on the faculty of language BT - constituting parametric variation JF - Linguistics in Potsdam N2 - In this paper I argue that both parametric variation and the alleged differences between languages in terms of their internal complexity straightforwardly follow from the Strongest Minimalist Thesis that takes the Faculty of Language (FL) to be an optimal solution to conditions that neighboring mental modules impose on it. In this paper I argue that hard conditions like legibility at the linguistic interfaces invoke simplicity metrices that, given that they stem from different mental modules, are not harmonious. I argue that widely attested expression strategies, such as agreement or movement, are a direct result of conflicting simplicity metrices, and that UG, perceived as a toolbox that shapes natural language, can be taken to consist of a limited number of markings strategies, all resulting from conflicting simplicity metrices. As such, the contents of UG follow from simplicity requirements, and therefore no longer necessitate linguistic principles, valued or unvalued, to be innately present. Finally, I show that the SMT does not require that languages themselves have to be optimal in connecting sound to meaning. KW - Parameters KW - Simplicity KW - Complexity KW - Uninterpretablity KW - Agreement KW - Movement Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-32221 SN - 1616-7392 SN - 1864-1857 IS - 28 SP - 9 EP - 38 ER - TY - THES A1 - Zbierzak, Anna Maria T1 - Isolation and characterization of the chilling sensitive 1 gene from Arabidopsis Y1 - 2009 CY - Potsdam ER - TY - GEN A1 - Zapf, Uta T1 - Außenpolitischer Burgfrieden? : Kontinuität als Konsens T1 - External "Burgfrieden"? : consistency as consensus N2 - Wie stabil ist die Außenpolitik der Großen Koalition? Aufgrund ihrer Position als stellvertretende außenpolitische Sprecherin der SPD ist es der Autorin möglich, neben den Gemeinsamkeiten auch die entscheidenden Unterschiede zu beleuchten. Vor dem Hintergrund mehrerer Beispiele, wie dem EU-Beitritt der Türkei, stellt sie den Konsens zwischen CDU/ CSU und SPD als fragil heraus. KW - Deutsche Außenpolitik KW - Europäische Union KW - Russland KW - SPD KW - German Foreign Policy KW - European Union KW - Russia KW - SPD Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-32702 SN - 0944-8101 ER - TY - JOUR A1 - Zamponi, Flavio A1 - Ansari, Zunaira A1 - von Korff Schmising, Clemens A1 - Rothhardt, Philip A1 - Zhavoronkov, Nickolai A1 - Woerner, Michael A1 - Elsaesser, Thomas A1 - Bargheer, Matias A1 - Trobitzsch-Ryll, Timo A1 - Haschke, Michael T1 - Femtosecond hard X-ray plasma sources with a kilohertz repetition rate N2 - Laser-driven plasma sources of femtosecond hard X-ray pulses have found widespread application in ultrafast X- ray diffraction. The recent development of plasma sources working at kilohertz repetition rates has allowed for diffraction experiments with strongly improved sensitivity, now revealing subtle fully reversible changes of the geometry of crystal lattices. We provide a brief review of this development and present a novel plasma source with an optimized mechanical and optical design, providing a high flux of several 10(10) photons/s at the Cu-K alpha energy of 8.04 keV and a pulse duration of a parts per thousand currency sign300 fs. First experiments, including the generation of Debye-Scherrer diffraction patterns from Si powder, demonstrate the high performance of this source. Y1 - 2009 UR - http://www.springerlink.com/content/100501 U6 - https://doi.org/10.1007/s00339-009-5171-9 SN - 0947-8396 ER -