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Musik
(2008)
Wasser : Zukunftsressource zwischen Menschenrecht und Wirtschaftsgut, Konflikt und Kooperation
(2008)
Schlussbemerkungen
(2008)
Statistiken
(2008)
Proceedings of the 2nd International Workshop on e-learning and Virtual and Remote Laboratories
(2008)
Background To improve the understanding of consequences of climate change for annual plant communities, I used a detailed, grid-based model that simulates the effect of daily rainfall variability on individual plants in five climatic regions on a gradient from 100 to 800 mm mean annual precipitation (MAP). The model explicitly considers moisture storage in the soil. I manipulated daily rainfall variability by changing the daily mean rain (DMR, rain volume on rainy days averaged across years for each day of the year) by ± 20%. At the same time I adjusted intervals appropriately between rainy days for keeping the mean annual volume constant. In factorial combination with changing DMR I also changed MAP by ± 20%. Results Increasing MAP generally increased water availability, establishment, and peak shoot biomass. Increasing DMR increased the time that water was continuously available to plants in the upper 15 to 30 cm of the soil (longest wet period, LWP). The effect of DMR diminished with increasing humidity of the climate. An interaction between water availability and density-dependent germination increased the establishment of seedlings in the arid region, but in the more humid regions the establishment of seedlings decreased with increasing DMR. As plants matured, competition among individuals and their productivity increased, but the size of these effects decreased with the humidity of the regions. Therefore, peak shoot biomass generally increased with increasing DMR but the effect size diminished from the semiarid to the mesic Mediterranean region. Increasing DMR reduced via LWP the annual variability of biomass in the semiarid and dry Mediterranean regions. Conclusion More rainstorms (greater DMR) increased the recharge of soil water reservoirs in more arid sites with consequences for germination, establishment, productivity, and population persistence. The order of magnitudes of DMR and MAP overlapped partially so that their combined effect is important for projections of climate change effects on annual vegetation.
Zur politischen Ökonomie von Dezentralisierungsprozessen : die Reformen im Wassersektor Marokkos
(2008)
Editorial
(2008)
Auf dem Weg zu einem Kompetenzmodell für den Sachunterricht : eine vergleichende Zusammenschau
(2008)
Kundenintegration zur Produktentwicklung in Virtuellen Welten : eine Bestandsaufnahme in second life
(2008)
Editorial
(2008)
The through space NMR shielding (TSNMRS) values of two tricyclobutabenzene (TCBB) derivatives 2, of the corresponding hexamethylene and hexaoxo TCBB derivatives 3, of [4n]annuleno[4n + 2]annulene 5 and of its tricyclobutadiene parent compound 4 have been ab initio calculated by the GIAO perturbation method employing the nucleus- independent chemical shift (NICS) concept of Paul von Ragué Schleyer, and visualized as iso-chemical shielding surfaces (ICSS). TSNMRS values can be successfully employed to quantify and visualize the aromaticity of the central, and in 5 also of the terminal benzene ring moieties.
The stereodynamic behaviour of 1-(trifluoromethylsulfonyl)piperidine 1, 4-(trifluoromethylsulfonyl)morpholine 2, 1,4-bis(trifluoromethylsulfonyl)piperazine 3 and 4-(trifluoromethylsulfonyl)thiomorpholine 1,1-dioxide 4 was studied by low-temperature 1H, 13C and 19F NMR spectroscopies. In acetone solution, compounds 1, 2 and 4 were found to exist as mixtures of two conformers in the ratio of 4:1, 4:1 and 8:1, respectively, differing by orientation of the CF3 group with respect to the ring. Compound 3 exists as a mixture of three conformers in the ratio of 3:28:69 also differing by the orientation of the two CF3 groups. Unlike the previously studied N-trifyl substituted 1,3,5-triheterocyclohexanes, the preferred conformers of compound 1 and of 1,4-diheterocyclohexanes 2-4 are those with the CF3 group directed outward from the ring, which is caused by intramolecular interactions of the oxygen atoms of the CF3SO2N groups with the equatorial hydrogens in the ;-position. B3LYP/6-311+G(d,p) calculations of the energy, geometry and NMR parameters corroborate the experimental data. The calculated Perlin effects for all conformers of compounds 1-4 as well as those measured for the major conformers of compounds 3 and 4 were analyzed by the use of the NBO analysis.
A new series of unsubstituted and substituted pyridinium salts bearing a 4-oxothiazolidinyl moiety has been prepared by an efficient rearrangement of 2-(1-bromoalkylidene)thiazolidin-4-ones. The process in based on three steps, namely carbon-bromine cleavage, bromine transfer, and substitution, each induced by pyridine or its derivatives, acting as base and reactant.
The spatial magnetic properties (Through Space NMR Shieldings - TSNMRS) of two cyclobutadiene derivatives (2 and 5) and of a number of cyclobutadiene dianion derivatives (3, 4 and 6-8) have been calculated by the GIAO perturbation method employing the Nucleus-Independent Chemical Shift (NICS) concept of P. v. Ragué Schleyer, and visualized as Iso-Chemical-Shielding Surfaces (ICSS) of various size and direction. TSNMRS values can be successfully employed to quantify and visualize the (anti)aromaticity of the compounds studied and to discuss the influence of Li+ complexation to cyclobutadiene dianion (4a, 7 and 8) on planar 4c,6e or three-dimensional 6c,6e aromaticity.
Through the ring closures of tetrahydroisoquinoline 1,3-amino alcohols bearing a phenyl group in the side- chain, diastereomers of novel 1- or 2-phenyl-substituted 1,3,2-oxazaphosphino[4,3-a]isoquinoline 4-oxides, and 1,2,3- oxathiazino[4,3-a]isoquinoline 4-oxides and 4,4-dioxides were prepared. NMR analysis and DFT calculations on the prepared tetrahydroisoquinoline-condensed 1,2,3-heterocycles revealed that their conformational equilibria of cis1-trans-cis2 type are influenced by the relative configuration of P-4 in the 1,3,2-oxazaphosphinanes, and by the position of the phenyl group in the 1,2,3-oxathiazines.
In order to obtain information on the number and symmetry of the different Eu3+ complexes formed with several hydroxybenzoic acids, ultra-low temperature luminescence measurements at 4.7 K were carried out. Hydroxybenzoic acids were used as simple model compounds for metal binding structures in humic substances (HS). Information on the complexes was extracted from high-resolution total luminescence spectra (TLS), which were obtained by scanning through the D-5(0) <-- F-7(0) transition of Eu(III) with a pulsed dye laser and measuring the emission in the wavelength range of the D- 5(0) --> F-7(0) and D-5(0) --> F-7(0) transitions simultaneously. By extracting the crystal field strength parameter N- v(B-2q) from the TLS, it was found that N-v(B-2q) was not directly correlated with the excitation energy. Further, the symmetry of the individual complexes formed was extracted from the experimental data. (C) 2007 Elsevier B.V. All rights reserved.
Die Heilung von formellen Eheschließungsmängeln bei Ehen mit Auslandsberührung nach deutschem Recht
(2008)
Performance-Measurement-Systeme und der Faktor Mensch : Leistungssteuerung effektiver gestalten
(2008)
Mit steigenden Rohstoffpreisen und den damit verbundenen hohen Exporterloesen ergibt sich fuer rohstoffreiche Laender eine zunehmende Forderung nach einem nachhaltigen Ressourcenmanagement, welches nicht nur die Entstehung wettbewerbsfaehiger Nicht-oel-Industrien lanciert, sondern vor allem auch rohstoffbedingte Schwankungen minimiert. Diese Arbeit untersucht in erster Linie Gruende, Aufbau und Struktur sowie die Effekte von Rohstofffonds, als Mittel eines optimalen Rohstoffmanagements. Als uebergeordnetes Ziel dieser Arbeit soll ermittelt werden, ob und wie sich Rohstofffonds auf unterschiedliche makrooekonomische Indikatoren auswirken. Diese werden im 2. Kapitel aus verschiedenen theoretischen Konzepten zur Erklaerung des "Ressourcenfluches" hergeleitet und koennen in Stabilitaets- und Nachhaltigkeitsvariablen unterteilt werden. Im 3. Kapitel wird analysiert, ob der Problematik des Ressourcenreichtums durch die Implementierung von Rohstofffonds zumindest teilweise entgegengewirkt werden kann und diese somit von ihrer Struktur her ein geeignetes Mittel zur Erreichung der Stabilitaets- und Nachhaltigkeitsziele darstellen. Dazu wird mit Hilfe eines "Infinite Horizon"-Modells das optimale Rohstoffmanagement des Staates fuer unterschiedliche Szenarien simuliert. Anschließend werden Fragen zu den speziellen Arten des Fonds, der Einbindung in den Staatshaushalt sowie dem operativen Portfoliomanagements eroertert. Nachdem die theoretische Ausgestaltung abgeschlossen ist, wird in Kapitel 4 die Einfuehrung von Rohstofffonds in einigen Laendern wie Norwegen, Russland und Aserbaidschan untersucht. Im 5. Kapitel erfolgt eine empirische Analyse, die auf Basis eines 30 Laender umfassenden "Unbalanced Panel" die Auswirkungen von Rohstofffonds auf den Ressourcenfluch und somit auf Stabilitaet und Nachhaltigkeit eines Landes innerhalb des Zeitraumes von 1970-2006 ermittelt. Abschließend werden im letzten Kapitel die Ergebnisse der gesamten Arbeit zusammengefasst und einer kurzen kritischen Wuerdigung unterzogen.