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The continuous progress in the structural and functional characterization of aquaporins increasingly attracts attention to study their roles in certain mammalian diseases. Although several structures of aquaporins have already been solved by crystallization, the challenge of producing sufficient amounts of functional proteins still remains. CF (cell free) expression has emerged in recent times as a promising alternative option in order to synthesize large quantities of membrane proteins, and the focus of this report was to evaluate the potential of this technique for the production of eukaryotic aquaporins. We have selected the mouse aquaporin 4 as a representative of mammalian aquaporins. The protein was synthesized in an E. coli extract based cell-free system with two different expression modes, and the efficiencies of two modes were compared. In both, the P-CF (cell-free membrane protein expression as precipitate) mode generating initial aquaporin precipitates as well as in the D-CF (cell-free membrane protein expression in presence of detergent) mode, generating directly detergent solubilized samples, we were able to obtain mg amounts of protein per ml of cell-free reaction. Purified aquaporin samples solubilized in different detergents were reconstituted into liposomes, and analyzed for the water channel activity. The calculated Pf value of proteoliposome samples isolated from the D-CF mode was 133 µm/s at 10°C, which was 5 times higher as that of the control. A reversible inhibitory effect of mercury chloride was observed, which is consistent with previous observations of in vitro reconstituted aquaporin 4. In this study, a fast and convenient protocol was established for functional expression of aquaporins, which could serve as basis for further applications such as water filtration.
Proteins of the Omp85 family are conserved in all kingdoms of life. They mediate protein transport across or protein insertion into membranes and reside in the outer membranes of Gram-negative bacteria, mitochondria, and chloroplasts. Omp85 proteins contain a C-terminal transmembrane β-barrel and a soluble N terminus with a varying number of polypeptide-transport-associated or POTRA domains. Here we investigate Omp85 from the cyanobacterium Anabaena sp. PCC 7120. The crystallographic three-dimensional structure of the N-terminal region shows three POTRA domains, here named P1 to P3 from the N terminus. Molecular dynamics simulations revealed a hinge between P1 and P2 but in contrast show that P2 and P3 are fixed in orientation. The P2-P3 arrangement is identical as seen for the POTRA domains from proteobacterial FhaC, suggesting this orientation is a conserved feature. Furthermore, we define interfaces for protein-protein interaction in P1 and P2. P3 possesses an extended loop unique to cyanobacteria and plantae, which influences pore properties as shown by deletion. It now becomes clear how variations in structure of individual POTRA domains, as well as the different number of POTRA domains with both rigid and flexible connections make the N termini of Omp85 proteins versatile adaptors for a plentitude of functions.
Auf dem NATO-Gipfel in Lissabon wurde soeben eine neue Sicherheitsstrategie beschlossen. Die Allianz werde nun „more effective, more engaged, and more efficient“ [Quelle http://www.nato.int/cps/en/natolive/news_68216.htm], so NATO-Generalsekretär Anders Fogh Rasmussen. Ohne die Folgen dieser neuen Strategie bereits jetzt evaluieren zu können, so kann man doch festhalten, dass mit dieser Strategie tatsächlich ein sich seit geraumer Zeit abzeichnender Paradigmenwechsel seinen vorläufigen Höhepunkt gefunden hat: Die NATO 3.0 als Risikomanager...
Wer in den letzten Monaten die Zeitungen aufschlug, kam um Hiobsbotschaften über den Zustand des Euros und Europas nicht herum. Von Hilferufen diverser peripherer Mitgliedsstaaten war allerorten die Rede, gar vom Auseinanderbrechen der Gemeinschaftswährung. Die Regierungsspitzen, den Marktmechanismen scheinbar hilflos ausgeliefert, beraten sich auf Krisengipfeln, beginnend mit dem ersten Sondergipfel zur Eurokrise am 11. Februar. Rettungsschirme überall, die dann zu klein sind für die Menge an Mitgliedsstaaten, die man spekulativ noch darunter verorten könnte. Hermann von Rompuy sieht die EU gar in einem Überlebenskampf ...
Man befindet sich im Krieg: Mit der zunehmenden Vernetzung der Weltent stehen neue Sicherheitsherausforderungen. Angriffe im Internet sind keine Seltenheit mehr und die Frage, wie man damit umgeht steht überall auf der Tagesordnung. Die NATO führte mit der „Cyber Coalition 2010 Exercise“ erstmals ein Cyberwar-Manöver durch und die USA aktivierten 2010 eine reine Cyberwar-Einheit [Quelle]. Sowohl auf staatlicher als auch zwischenstaatlicher Ebene haben sich die Räder in Bewegung gesetzt um den neuen Bedrohungen zu begegnen....
Moderately elevated levels of plasma plant sterols have been suspected to be causally involved in atherosclerosis. The aim of this study was to investigate whether plant sterols and other markers of sterol metabolism predicted all-cause and cardiovascular mortality in participants of the Ludwigshafen Risk and Cardiovascular health (LURIC) study. A total of 1,257 individuals who did not use statins and at baseline had a mean (± SD) age of 62.8 (± 11.0) years were included in the present analysis. Lathosterol, cholestanol, campesterol, and sitosterol were measured to estimate cholesterol synthesis and absorption. The mean (± SD) time of the follow-up for all-cause and cardiovascular mortality was 7.32 (± 2.3) years. All-cause (P = 0.001) and cardiovascular (P = 0.006) mortality were decreased in the highest versus the lowest lathosterol to cholesterol tertile. In contrast, subjects in the third cholestanol to cholesterol tertile had increased all-cause (P < 0.001) and cardiovascular mortality (P = 0.010) compared with individuals in the first tertile. The third campesterol to cholesterol tertile was associated with increased all-cause mortality (P = 0.025). Sitosterol to cholesterol tertiles were not significantly related to all-cause or cardiovascular mortality. The data suggest that high absorption and low synthesis of cholesterol predict increased all-cause and cardiovascular mortality in LURIC participants.
Vibronic (vibrational-electronic) transition is one of the fundamental processes in molecular physics. Indeed, vibronic transition is essential both in radiative and nonradiative photophysical or photochemical properties of molecules such as absorption, emission, Raman scattering, circular dichroism, electron transfer, internal conversion, etc. A detailed understanding of these transitions in varying systems, especially for (large) biomolecules, is thus of particular interest. Describing vibronic transitions in polyatomic systems with hundreds of atoms is, however, a difficult task due to the large number of coupled degrees of freedom. Even within the relatively crude harmonic approximation, such as for Born-Oppenheimer harmonic potential energy surfaces, the brute-force evaluation of Franck-Condon intensity profiles in a time-independent sum-over-states approach is prohibitive for complex systems owing to the vast number of multi-dimensional Franck-Condon integrals. The main goal of this thesis is to describe a variety of molecular vibronic transitions, with special focus on the development of approaches that are applicable to extended molecular systems. We use various representations of Fermi’s golden rule in frequency, time and phase spaces via coherent states to reduce the computational complexity. Although each representation has benefits and shortcomings in its evaluation, they complement each other. Peak assignment of a spectrum can be made directly after calculation in the frequency domain but this sum-over-states route is usually slow. In contrast, computation is considerably faster in the time domain with Fourier transformation but the peak assignment is not directly available. The representation in phase space does not immediately provide physically-meaningful quantities but it can link frequency and time domains. This has been applied to, herein, for example (non-Condon) absorption spectra of benzene and electron transfer of bacteriochlorophyll in the photosynthetic reaction center at finite temperature. This work is a significant step in the treatment of vibronic structure, allowing for the accurate and efficient treatment of complex systems, and provides a new analysis tool for molecular science.
The KADoNiS (Karlsruhe Astrophysical Database of Nucleosynthesis in Stars) project is an online
database (www.kadonis.org) for cross sections relevant to the s-process and the p-process.
The first version was an updated sequel to the previous Bao et al. [1] compilations from 1987
and 2000 for (n; g) cross sections relevant to Big Bang and s-process nucleosynthesis. The first
update, KADoNiS v0.2, was published in 2006 [2]. It contained mainly Maxwellian averaged
(n; g) cross sections relevant to the s-process, and some experimental charged particle induced
reaction relevant to the p-process. After that a second update was presented in 2009 [3].
Recently, we started to collect and review all existing experimental data relevant for p-process
nucleosynthesis and to provide a user-friendly database based on the KADoNiS framework. The
p-process part of the KADoNiS database is currently being extended and will include all available
experimental data from (p; g), (p;n), (p;a), (a,g), (a;n) and (a; p) reactions in or close to the
respective Gamow window.
Die Präkonditionierung mit den bakteriellen Zellwandbestandteilen Lipopolysaccharid (LPS) oder Lipoteichonsäure (LTA) führt in vivo zu einer Reduktion der myokardialen Infarktgröße nach Ischämie und Reperfusion (I/R). Hierbei wird durch die Präkonditionierung u.a. die Akkumulation neutrophiler Granulozyten im Ischämiegebiet während der Reperfusionsphase reduziert und somit einer der wichtigsten Mechanismen bei der Entstehung des Reperfusionsschadens am Herzen vermindert. In dieser Studie bedienten wir uns eines ex vivo Modells nach Langendorff mit regionaler I/R und zellfreier Perfusion. Wir konnten erstmalig eine LTA-Präkonditionierung in einem leukozytenfreien System zeigen und somit demonstrieren, dass die LTA-Präkonditionierung Mechanismen involviert, die unabhängig sind von einer Akkumulation neutrophiler Granulozyten. 24 Stunden nach einer Vorbehandlung der Ratten mit LPS, LTA, Kochsalz und/oder Dexamethason wurden die Herzen entfernt und retrograd mit oxygenierter Krebs-Henseleit-Lösung perfundiert. Die Herzen wurden einer 20-minütigen Ischämie, gefolgt von einer 2-stündigen Reperfusionsphase, unterzogen. Das Infarktrisikogebiet (Evans-Blue-Färbung) und das Infarktgebiet (pNBT-Färbung) wurden planimetrisch bestimmt. Die ischämische Präkonditionierung (IPC) wurde als Positivkontrolle unseres Modells verwendet. LTA- und LPS-Präkonditionierung führten - ebenso wie IPC - bei gleicher Dosierung in vergleichbarem Umfang zu einer signifikanten Reduktion der Infarktgröße. Dieser Effekt konnte durch Vorbehandlung mit Dexamethason vollständig aufgehoben werden, so dass gefolgert werden kann, dass die Protektion durch LPS bzw. LTA. von der Modulation der inflammatorischen Vorgänge im Endothel und Myokard mit abhängt.
Surface measurements of aerosol and ice nuclei (IN) at a Central European mountain site during an episode of dust transport from the Sahara are presented. Ice nuclei were sampled by electrostatic precipitation on silicon wafers and were analyzed in an isothermal static vapor diffusion chamber. The transport of mineral dust is simulated by the Eulerian regional dust model DREAM. Ice nuclei and mineral dust are significantly correlated, in particular IN number concentration and aerosol surface area. The ice nucleating characteristics of the aerosol as analyzed with respect to temperature and supersaturation are similar during the dust episode than during the course of the year. This suggests that dust may be a main constituent of ice nucleating aerosols in Central Europe.
Surface measurements of aerosol and ice nuclei (IN) at a Central European mountain site during an episode of dust transport from the Sahara are presented. Transport is simulated by the Eulerian regional dust model DREAM. Ice nuclei and mineral dust are significantly correlated. The highest correlation is found between IN concentration and aerosol surface area. The ice nucleating characteristics of the aerosol with respect to temperature and supersaturation are similar during the dust episode than during the course of the year. This suggests that dust is always a dominant constituent of ice nucleating aerosols in Central Europe.
Durch die steigende Bedeutung von multimedialen Lernmaterialien in der Lehre und in der Wirtschaft, wachsen die Anforderungen, die an die Herstellung der Materialien gestellt werden. Verwaltung, Archivierung und Wiederverwendbarkeit sind die zentralen Begriffe um die Effektivität von multimedialen Lernmaterialien zu steigern und damit auch kommerziellen Erfolg zu erzielen. Es ist effektiv wenn Lernmaterialien ein Thema nicht erneut aufarbeiten, wenn es bereits ausreichend Materialien dazu gibt. Vorhandene Materialien können genutzt werden und sparen somit Ressourcen, die ansonsten zur Herstellung neuer Materialien genutzt werden müssten. In dieser Arbeit werden Metadaten als Mittel eingesetzt, um die Effektivität zu steigern. Dabei soll vor allem der Mehrwert durch die Verwendung von Metadaten deutlich gemacht werden. Eine Analyse aktueller Autorensysteme soll zeigen, wie Metadaten bereits eingesetzt werden und wo Probleme existieren. Die Stärken und Schwächen der untersuchten Autorensysteme werden für die Anforderungsanalyse einer Erweiterung des Autorensystems LernBar verwendet. Um den Mehrwert der Metadaten deutlich zu machen, soll der gesamte Autorenprozess innerhalb der LernBar erweitert werden. Das heißt, dass der gesamte Ablauf, vom Erfassen bis zum Verwenden der Metadaten, abgebildet wird. Im Fokus der Erweiterung steht die Unterstützung des Autors bei der Erstellung von Lernmaterialien. Vorlagen und automatisierte Vorgänge dienen der Bedienbarkeit der neuen Funktionen.
Background: Many disabling human retinal disorders involve the central retina, particularly the macula. However, the commonly used rodent models in research, mouse and rat, do not possess a macula. The purpose of this study was to identify small laboratory rodents with a significant central region as potential new models for macular research.
Methodology/Principal Findings: Gerbillus perpallidus, Meriones unguiculatus and Phodopus campbelli, laboratory rodents less commonly used in retinal research, were subjected to confocal scanning laser ophthalmoscopy (cSLO), fluorescein and indocyanine green angiography, and spectral-domain optical coherence tomography (SD-OCT) using standard equipment (Heidelberg Engineering HRA1 and Spectralis™) adapted to small rodent eyes. The existence of a visual streak-like pattern was assessed on the basis of vascular topography, retinal thickness, and the topography of retinal ganglion cells and cone photoreceptors. All three species examined showed evidence of a significant horizontal streak-like specialization. cSLO angiography and retinal wholemounts revealed that superficial retinal blood vessels typically ramify and narrow into a sparse capillary net at the border of the respective area located dorsal to the optic nerve. Similar to the macular region, there was an absence of larger blood vessels in the streak region. Furthermore, the thickness of the photoreceptor layer and the population density of neurons in the ganglion cell layer were markedly increased in the visual streak region.
Conclusions/Significance: The retinal specializations of Gerbillus perpallidus, Meriones unguiculatus and Phodopus campbelli resemble features of the primate macula. Hence, the rodents reported here may serve to study aspects of macular development and diseases like age-related macular degeneration and diabetic macular edema, and the preclinical assessment of therapeutic strategies.
The display of foreign polypeptides and proteins on the surface of viruses or cells provides an important tool for the engineering of biomolecules and the analysis of their interactions with binding partners. The most extensively used display platform is the coat protein of the filamentous bacteriophage (Smith, 1985). Phage display libraries have often been selected for polypeptides, e.g. single chain (sc) antibodies that bind to a protein of interest, but in vivo selection could only be demonstrated for peptides so far. An alternative display platform is the retrovirus murine leukemia virus (MLV). Here, polypeptides are displayed at the N-terminus of the viral envelope glycoprotein. Proof of principle for this platform was demonstrated for protease substrate libraries, which can be selected through coupling proteolytic activation with viral infectivity (Buchholz et al., 1998). Selection of the library CX4A on living cells resulted in viruses with more than three orders of magnitude improved spreading efficiency through tumor cells (Hartl et al., 2005). Also scAb libraries have recently been displayed and selected using retroviruses (Urban et al., 2005). The library scFvlibxMo displays the repertoire of phage display preselected sc antibodies for laminin-1 binding. The retrovirus based selection process resulted in laminin-specific sc antibodies with improved expression levels in mammalian cells.
This thesis describes the in vivo (i.e. in mouse tumor models) selection of the C-X4-A and scFvlibxMo for tumor homing upon systemic delivery.
For selection of the protease substrate library C-X4-A a subcutaneous tumor was induced in SCID mice followed by three systemic injections of the library. The selection process was monitored over a period of 34 days. After the incubation period mice were sacrificed and virus load in organs and tumor determined. PCR analysis after 34 days showed that virus from the library had preferentially infected the tumor. Sequence analysis showed the selection of protease substrates with the most prominent one with a frequency of over 65%. The four most prominent protease substrate variants where reconstituted into the original viral backbone for further investigation (C-SK-A, C-HI-A, C-HM-A and C-HS-A). Interestingly, these viruses exhibited a reduced spreading capacity in vitro on HT1080 cells as compared to the C-AK-A virus, which had previously been selected on HT1080 cells. When assayed for tumor homing, however, viruses C-HI-A and C-HS-A had clearly improved in comparison to C-AK-A. Tumor tissue had been infected at rates of over 55% while virus load of extratumoral organs was very low (infection rates <0.7 for C-HS-A and <0.02 for C-HI-A). Tumor targeting capacity had thus been improved over 10-fold by the in vivo selection of the C-X4-A library.
The experimental set up for the in vivo selection of the scFvlibxMo library was performed according to that of the C-X4-A library. Fingerprint analysis of the selected viruses that infected tumor tissue resulted in the identification of seven antibody variants showing unique CDR3 sequences. Two prominent clones (M49T-A and M49T-B) were cloned back into the MoMLV genome for further analysis of the reconstituted viruses. While variant B bound laminin-1 efficiently, variant A was unable to do so, although it was selected at highest frequency (76%). Both reconstituted viruses were equally well infectious and spread through HT1080rec1 cells at a similar efficiency as MoMLV. In an in vivo competition experiment the selected viruses clearly out-competed a laminin-1 binding reference virus L36xMo for tumor homing. To understand the molecular driving forces behind the in vivo selection process the epitope of the selected scFv M49T-A was identified using a phage peptide library approach. In silico analysis led to the identification of a small group of possible antigens, including tenascin, fibronectin and collagen.
The data described in this thesis demonstrate that the retrovirus display platform is capable of allowing the in vivo selection of protease substrates and scFvs. Notably, the replication competence of the system introduced an additional level of complexity to the library. The performed in vivo selections significantly enhanced tumor tropism. Selective infection of tumor cells combined with transfer of anti-tumoral genes is an attractive strategy for cancer therapy being in focus of current research. The viruses selected in this thesis build prime candidates for targeted retrovirus based tumor therapy.
Aufbau der Arbeit Auf der Grundlage einer Definition von Integrationsprozessen bzw. Integrationszuständen (Kap. 2.1) werden Heterogenitätsmerkmale diskutiert, die für Anerkennungsunterschiede zwischen Ingroup und Outgroup verantwortlich sein können (Kap. 2.1.2). Anschließend werden Integrations- und Desintegrationsmechanismen moderner Gesellschaften aufgezeigt und Erkenntnisse der Vorurteilsforschung zur Verbesserung der Outgroup-Anerkennung erörtert (Kap. 2.1.3 und 2.1.4). Im darauffolgenden Kapitel 2.2 werden Formen des Sports im Hinblick auf deren Integrations- und Desintegrationspotenziale diskutiert. Kapitel 2.3 beschäftigt sich zunächst mit der grundlegenden pädagogischen Rahmung des erziehenden Sportunterrichts, stellt einzelne Integrationsansätze vor und legt dabei den Fokus auf die Frage der bewussten oder unbewussten Auseinandersetzung mit Heterogenität. Da Kooperatives Lernen als eine erfolgversprechende Methode für gelingende Integration gehandelt wird und diese Methode zudem Integrationsmechanismen sowie Kontakthypothese berücksichtigt, wird sie in Kapitel 2.4 ausführlich beschrieben. Nachdem die wichtigsten Theorien zu heterogenitätsbedingten Anerkennungsunterschieden sowie integrationspädagogischen Überlegungen im Sportunterricht behandelt worden sind, schließt der Theorieteil mit der Ableitung der Fragestellungen (Kap. 2.5). Fragestellungen: In der soziologischen Untersuchung wird der Frage nach den tatsächlich desintegrierenden Heterogenitätsmerkmalen im Sportunterricht nachgegangen. In der pädagogischen Untersuchung wird erforscht, ob Kooperatives Lernen im Sportunterricht in der Lage ist, den selektiven Einfluss der desintegrierenden Heterogenitätsmerkmale abzubauen.
Wassergefiltertes Infrarot A (wIRA) ist eine spezielle Form der Wärmestrahlung mit hohem Penetrationsvermögen ins Gewebe bei geringer thermischer Oberflächenbelastung. wIRA entspricht dem Großteil der Sonnenwärmestrahlung, die in gemäßigten Klimazonen die Erdoberfläche wasserdampfgefiltert erreicht. wIRA steigert die drei energetisch für die Wundheilung wichtigen Faktoren Temperatur, Sauerstoffpartialdruck und Durchblutung im Gewebe. wIRA mindert Schmerzen, Entzündung und Wundsekretion. Entsprechend kann wIRA sehr gut zur Verbesserung der Wundheilung bei akuten und chronischen Wunden eingesetzt werden.
Poster presentation at 5th German Conference on Cheminformatics: 23. CIC-Workshop Goslar, Germany. 8-10 November 2009 We demonstrate the theoretical and practical application of modern kernel-based machine learning methods to ligand-based virtual screening by successful prospective screening for novel agonists of the peroxisome proliferator-activated receptor gamma (PPARgamma) [1]. PPARgamma is a nuclear receptor involved in lipid and glucose metabolism, and related to type-2 diabetes and dyslipidemia. Applied methods included a graph kernel designed for molecular similarity analysis [2], kernel principle component analysis [3], multiple kernel learning [4], and, Gaussian process regression [5]. In the machine learning approach to ligand-based virtual screening, one uses the similarity principle [6] to identify potentially active compounds based on their similarity to known reference ligands. Kernel-based machine learning [7] uses the "kernel trick", a systematic approach to the derivation of non-linear versions of linear algorithms like separating hyperplanes and regression. Prerequisites for kernel learning are similarity measures with the mathematical property of positive semidefiniteness (kernels). The iterative similarity optimal assignment graph kernel (ISOAK) [2] is defined directly on the annotated structure graph, and was designed specifically for the comparison of small molecules. In our virtual screening study, its use improved results, e.g., in principle component analysis-based visualization and Gaussian process regression. Following a thorough retrospective validation using a data set of 176 published PPARgamma agonists [8], we screened a vendor library for novel agonists. Subsequent testing of 15 compounds in a cell-based transactivation assay [9] yielded four active compounds. The most interesting hit, a natural product derivative with cyclobutane scaffold, is a full selective PPARgamma agonist (EC50 = 10 ± 0.2 microM, inactive on PPARalpha and PPARbeta/delta at 10 microM). We demonstrate how the interplay of several modern kernel-based machine learning approaches can successfully improve ligand-based virtual screening results.
With the help of miniaturized GPS recorders I recorded 167 tracks of 48 individual pigeons during their flight from 6 different sites around Frankfurt. The experiments consisted of two main series of repeated releases from two sites 30 km north and south from the pigeons' home loft. From the site in the south the pigeons homed 12 times and from the site in the north 16 times. After the final release from these sites, the pigeons were released at 60 km distance from home. These additional sites were selected so that the pigeons would presumably fly over the previous release site with which they were highly familiar. After conclusion of the main series two additional releases were performed, one within the magnetic anomaly of the Vogelsberg and one in a magnetically quiet region. To make these releases comparable, both release sites were selected so that the distance from the home loft was 40 km. All data obtained during these experiments were subjected to a threefold analysis, mostly based on methods that I had developed by myself or adapted for this specific study. In the first step, data were analyzed traditionally, evaluating variables similar to those that can be found in current literature. I therefore calculated values that correspond to those obtained by visual observation, like virtual vanishing bearings and intervals after one minute and after 2.5 km. Additionally I calculated the efficiency of the flights and efficiencies for specific portions of each flight, to derive variables that describe the behavior after vanishing. In the second step, which served also as a preparation for the mathematical analysis, the flight of the pigeons was separated into distinctive phases of the flight by the so-called points of decision. The flight of the pigeon can usually be separated into an initial phase of flying about, a departure and/or final homing phase. In more complex cases, however, several points of decision and a multitude of intermediary phases can be defined. Yet, the initial phase, the departure phase and the final homing phase can be defined for all tracks and therefore have been selected as appropriate candidates for a thorough analysis. In the last step I employed the so-called method of time lag embedding to reconstruct the underlying navigational process of the pigeons' homing flight. This method is based on the principles of chaos theory and is regularly employed for the analysis of dynamic systems. Its application allows the reconstruction of the underlying processes from experimentally recorded data without any a priori knowledge of the underlying system itself. For these reconstructed systems I calculated characteristic properties which are unique for each system. These are the so-called correlation dimension, describing the complexity of the system, and the so-called largest Lyapunov exponent, describing its predictability. Based on the knowledge gathered from these reconstructions, I used a variation of the previous methods to identify navigational phases, by calculating the correlation dimension as a sliding mean over the complete track. From these data I then derived further characteristics of the underlying process, such as its precision and differences in complexity depending on the pigeon's current position. ...