Search Results - (Author, Cooperation:J. Korb)
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1Latest Papers from Table of Contents or Articles in PressStaff View
Publication Date: 2014-02-18Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: Animals ; Bioengineering/*methods ; *Computer-Aided Design ; Facility Design and Construction/*methods ; *Isoptera ; *Mass Behavior ; Robotics/*methodsPublished by: -
2Latest Papers from Table of Contents or Articles in PressP. Abbot ; J. Abe ; J. Alcock ; S. Alizon ; J. A. Alpedrinha ; M. Andersson ; J. B. Andre ; M. van Baalen ; F. Balloux ; S. Balshine ; N. Barton ; L. W. Beukeboom ; J. M. Biernaskie ; T. Bilde ; G. Borgia ; M. Breed ; S. Brown ; R. Bshary ; A. Buckling ; N. T. Burley ; M. N. Burton-Chellew ; M. A. Cant ; M. Chapuisat ; E. L. Charnov ; T. Clutton-Brock ; A. Cockburn ; B. J. Cole ; N. Colegrave ; L. Cosmides ; I. D. Couzin ; J. A. Coyne ; S. Creel ; B. Crespi ; R. L. Curry ; S. R. Dall ; T. Day ; J. L. Dickinson ; L. A. Dugatkin ; C. El Mouden ; S. T. Emlen ; J. Evans ; R. Ferriere ; J. Field ; S. Foitzik ; K. Foster ; W. A. Foster ; C. W. Fox ; J. Gadau ; S. Gandon ; A. Gardner ; M. G. Gardner ; T. Getty ; M. A. Goodisman ; A. Grafen ; R. Grosberg ; C. M. Grozinger ; P. H. Gouyon ; D. Gwynne ; P. H. Harvey ; B. J. Hatchwell ; J. Heinze ; H. Helantera ; K. R. Helms ; K. Hill ; N. Jiricny ; R. A. Johnstone ; A. Kacelnik ; E. T. Kiers ; H. Kokko ; J. Komdeur ; J. Korb ; D. Kronauer ; R. Kummerli ; L. Lehmann ; T. A. Linksvayer ; S. Lion ; B. Lyon ; J. A. Marshall ; R. McElreath ; Y. Michalakis ; R. E. Michod ; D. Mock ; T. Monnin ; R. Montgomerie ; A. J. Moore ; U. G. Mueller ; R. Noe ; S. Okasha ; P. Pamilo ; G. A. Parker ; J. S. Pedersen ; I. Pen ; D. Pfennig ; D. C. Queller ; D. J. Rankin ; S. E. Reece ; H. K. Reeve ; M. Reuter ; G. Roberts ; S. K. Robson ; D. Roze ; F. Rousset ; O. Rueppell ; J. L. Sachs ; L. Santorelli ; P. Schmid-Hempel ; M. P. Schwarz ; T. Scott-Phillips ; J. Shellmann-Sherman ; P. W. Sherman ; D. M. Shuker ; J. Smith ; J. C. Spagna ; B. Strassmann ; A. V. Suarez ; L. Sundstrom ; M. Taborsky ; P. Taylor ; G. Thompson ; J. Tooby ; N. D. Tsutsui ; K. Tsuji ; S. Turillazzi ; F. Ubeda ; E. L. Vargo ; B. Voelkl ; T. Wenseleers ; S. A. West ; M. J. West-Eberhard ; D. F. Westneat ; D. C. Wiernasz ; G. Wild ; R. Wrangham ; A. J. Young ; D. W. Zeh ; J. A. Zeh ; A. Zink
Nature Publishing Group (NPG)
Published 2011Staff ViewPublication Date: 2011-03-25Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsKeywords: *Altruism ; Animals ; *Biological Evolution ; Cooperative Behavior ; Female ; Game Theory ; *Genetic Fitness ; Genetics, Population ; Heredity ; Humans ; Male ; *Models, Biological ; Phenotype ; Reproducibility of Results ; *Selection, Genetic ; Sex RatioPublished by: -
3Articles: DFG German National LicensesKorb, J.-P. ; Bredel, Th. ; Chachaty, C. ; Van Der Maarel, J. R. C.
College Park, Md. : American Institute of Physics (AIP)
Published 1990Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: We propose a theory of dipolar spin relaxation for lamellar geometry where one of the spin species diffuses on an infinite plane while the other diffuses within an infinite layer of finite thickness. Analytical expressions of the frequency dependence of the spectral densities and spin relaxation rates are given. The theoretical frequency variation of the longitudinal relaxation rate appears to be drastically dependent of the anisotropic diffusion ratio and on the thickness of the layer. An application of this theory to lamellar lyotropic liquid crystal gives the spatial distribution of an organic counterion solute in the bilayer from the frequency variation of the 31P longitudinal relaxation rates of the surfactant. This gives some information about the surfactant-organic counterion interaction and the hydration degree of the phosphate group.Type of Medium: Electronic ResourceURL: -
4Articles: DFG German National LicensesKorb, J.-P. ; Xu, Shu ; Jonas, J.
College Park, Md. : American Institute of Physics (AIP)
Published 1993Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: A theory of dipolar relaxation by translational diffusion of a nonwetting liquid confined in model porous media is presented. We obtain expressions of the rates of spin-lattice relaxation 1/T1, spin–spin relaxation 1/T2, and spin-lattice relaxation in the rotating frame 1/T1ρ, which depend on the average pore size d. The frequency variations of these rates are intermediate between the two-dimensional and three-dimensional results. At small frequency they vary logarithmically for small d and tend progressively to a constant with increasing d. For small pore sizes we obtain quadratic confinement dependences of these rates (∝1/d2), at variance with the linear (∝1/d) relation coming from the biphasic fast exchange model usually applied for a wetting liquid in porous media. We apply such a theory to the 1H NMR relaxation of methylcyclohexane liquid in sol-gel porous silica glasses with a narrow pore-size distribution. The experiments confirm the theoretical predictions for very weak interacting solvent in porous silica glasses of pore sizes varying in the range of 18.4–87.2 A(ring) and in the bulk. At the limit of small pores, the logarithmic frequency dependencies of 1/T1ρ and 1/T1 observed over several decades of frequency are interpreted with a model of unbounded two-dimensional diffusion in a layered geometry. The leveling off of the 1/T1ρ low-frequency dependence is interpreted in terms of the bounded two-dimensional diffusion due to the finite length L of the pores. An estimate of a finite size of L=100 A(ring) is in excellent agreement with the experimental results of the transmission electron microscopy study of platinium-carbon replicated xerogels.Type of Medium: Electronic ResourceURL: -
5Articles: DFG German National LicensesKorb, J.-P. ; Delville, A. ; Xu, Shu ; Demeulenaere, G. ; Costa, P. ; Jonas, J.
College Park, Md. : American Institute of Physics (AIP)
Published 1994Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: The relative roles of surface and topological effects on the nuclear relaxation rates T−11, T−12, and T−11ρ of polar or nonpolar liquids in porous sol-gel silica glasses are identified via their very different pore size and frequency dependences. On the basis of theory, experimental relaxation rates, and molecular dynamics simulations for the modeled porous systems, the 1/Ti's are interpreted in terms of a linear combination of bulk, confinement, and surface effects: 1/Ti = 1/Tibulk + ai/R2+ bi/R, where R is the average pore size and ai and bi are given in terms of the usual relaxation parameters of the studied molecular species. This simple expression which allows the determination of the relative roles of surface and topological effects has been used to fit the observed 1H NMR relaxation rates as a function of pore size and frequency for methylcyclohexane, nitrobenzene, pyridine, and toluene both for nonmodified and surface modified porous silica glasses. Using this method, the surface (∝1/R) and pure geometrical (∝1/R2) relaxation contributions are evaluated and the surface and translational correlation times are calculated. More generally, the experimental data allow us to explain the following seemingly paradoxical results obtained for confined liquids: (i) The pure confinement effect is independent of the polarities of the liquid molecules in pores and is very sensitive to the frequency. (ii) The finding of the frequency variation of T−11 and T−11ρ both for polar or nonpolar liquids confined to small pores, shows that the geometrical confinement effects dominate over the surface interaction effects at low frequency and for small pores.Type of Medium: Electronic ResourceURL: -
6Articles: DFG German National LicensesKorb, J.-P. ; Ahadi, M. ; Zientara, G. P. ; Freed, J. H.
College Park, Md. : American Institute of Physics (AIP)
Published 1987Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: The dynamic effects of pair correlation functions (pcf) on spin relaxation by translational diffusion in infinite two-dimensional fluids are considered explicitly through a Smoluchowski equation, for the usual conditional probability, with appropriate boundary conditions, especially at the contact separation of the interacting pair of molecules. The solution of this equation by finite difference techniques permits the calculation of time correlation functions, spectral densities, and spin-relaxation rates associated with a dipolar relaxation mechanism between the spin-bearing molecules. Comparison of the two-dimensional spin-relaxation results obtained with different pcf is presented. The spectral densities and spin-relaxation rates are indeed found to be significantly altered by the pcf. For example, for a nonuniform pcf, the two-dimensional spectral densities, at (and above) the Larmor frequency ω0, are greater for translational correlation times τt that are an order of magnitude faster than τt=ω−10 which provides the maximum spectral density in bulk theory. This fast motion result is consistent with the two-dimensional dynamical results found by other techniques. Moreover for a nonuniform pcf and a single translational correlation time, two well-defined minima are found in the variation of the spin-lattice relaxation time with the diffusion coefficient. This could be very useful for interpreting the spin-relaxation data of diffusing complexes in clays, intercalation compounds, and bilayers.Type of Medium: Electronic ResourceURL: -
7Articles: DFG German National LicensesStaff View
ISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: The results of a theoretical and experimental study of the confinement effects on molecular dynamics of nonpolar liquids in porous silica glasses prepared by the sol-gel process are discussed. The natural abundance 13C and 33S NMR spin-lattice relaxation times of liquid CS2 are reported as a function of pore radius in the range from 15 Å to 102 Å over the temperature range of 168 K to 293 K. Since spin-rotation interactions dominate the 13C relaxation at higher temperatures these experiments allowed us for the first time to follow the confinement effects on angular momentum correlation times. The low-temperature 13C T1 data and the 33S T1 data provide information about reorientational motions. In order to interpret the experimental NMR relaxation data, a theoretical model for anisotropic molecular reorientation and angular velocity, which accounts for the motional behavior of nonpolar liquids confined to nanopores, is proposed. This model predicts an increase of the reorientational and angular momentum correlation times when the pore size is decreased. Application of this theoretical model to the interpretation of the CS2 NMR relaxation data and to earlier relaxation results obtained for confined nonpolar cyclohexane-d12 liquid proved successful. © 1997 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
8Articles: DFG German National LicensesStaff View
ISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: An extension of our previous theory of spin relaxation by translational diffusion in two-dimensional (2D) systems is proposed by considering the very nonuniform radial molecular distribution observed at short intermolecular distance. This increases greatly the absolute values of the spin-lattice relaxation rates T−11 and enhances the size effects on their diffusion (or temperature) dependences. The existence of two maxima in these dependences should facilitate the interpretation of experimental data in 2D heterogeneous systems.Type of Medium: Electronic ResourceURL: -
9Articles: DFG German National LicensesStaff View
ISSN: 0303-2647Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: BiologyType of Medium: Electronic ResourceURL: -
10Articles: DFG German National LicensesStaff View
ISSN: 0022-2364Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: PhysicsType of Medium: Electronic ResourceURL: -
11Articles: DFG German National LicensesStaff View
ISSN: 0022-2364Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: PhysicsType of Medium: Electronic ResourceURL: -
12Articles: DFG German National LicensesStaff View
ISSN: 0022-2364Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: PhysicsType of Medium: Electronic ResourceURL: -
13Articles: DFG German National LicensesStaff View
ISSN: 0009-2614Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: Chemistry and PharmacologyPhysicsType of Medium: Electronic ResourceURL: -
14Articles: DFG German National LicensesPospíšek, M. ; Palková, Z. ; Janderová, B. ; Korb, J.
Oxford, UK : Blackwell Publishing Ltd
Published 1994Staff ViewISSN: 1574-6968Source: Blackwell Publishing Journal Backfiles 1879-2005Topics: BiologyNotes: Abstract Virus-like particles (VLPs) have been isolated from the yeast Endomyces magnusii. The VLPs measure 43 nm in diameter and contain six species of dsRNA (0.78, 0.83, 1.77, 1.84, 2.64, 4.30 kb respectively). E. magnusii produces a ‘toxic’ protein, which reduces the growth, and changes the colony morphology, of sensitive strains of Hansenula sp. growing on solid media. All strains of E. magnusii tested produced the ‘toxin’ and contained the VLPs. Current procedures of curing failed to destroy the ability to produce the ‘toxin’.Type of Medium: Electronic ResourceURL: -
15Articles: DFG German National LicensesStaff View
ISSN: 1420-9071Source: Springer Online Journal Archives 1860-2000Topics: BiologyMedicineNotes: Zusammenfassung Sphäroidale und phag-ähnliche Form des Hühner-Leukosis-Virus (BAI, Stamm A) wird der Existenz eines kontrahierbaren Systems (Interaktion mit ATP) zugeschrieben. Formveränderungen des Viruspartikels unter ATP-Einfluss werden in vitro dargestellt, wobei Parachlormorcuribenzoat, Phenylmercuriborat und N-Äthylmaleimid als Inhibitoren wirken.Type of Medium: Electronic ResourceURL: -
16Articles: DFG German National LicensesStaff View
ISSN: 0022-2364Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: PhysicsType of Medium: Electronic ResourceURL: -
17Articles: DFG German National LicensesStaff View
ISSN: 0022-2364Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: PhysicsType of Medium: Electronic ResourceURL: -
18Articles: DFG German National LicensesStaff View
ISSN: 1420-9098Keywords: Key words: Gallery forest, Ivory Coast, savanna, termites, thermoregulation.Source: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Summary: We determined density and distribution of the mounds of the fungus-cultivating termite Macrotermes bellicosus (Smeathman) in two habitats (shrub savanna and gallery forest) of the Comoé National Park (Ivory Coast, West Africa). We measured height, basal width, and interior and exterior temperatures of mounds in both habitats, and established a new method to measure the surface area of mounds.¶ In the shrub savanna, M. bellicosus mounds reached high densities (up to 22.7 live mounds/ha), whereas in the gallery forest mounds could only be found in open stands and at comparatively low densities (up to 6.5 live mounds/ha).¶ Ambient temperature had an important influence on the architecture of the mounds. Mounds in the warmer, but thermally more fluctuating shrub savanna were more structured with many ridges and turrets than the dome-like, compact mounds in the cooler, more equable gallery forest. The surface complexity was quantified as the ratio of surface (= rsf), which is the quotient of the real surface to the minimal possible surface of an ideal cone of the same height and basal width as the measured mound. By manipulating ambient temperatures, we were able to demonstrate causal relationships between temperature and mound shape. In the gallery forest, where shade was reduced surface complexity increased on mounds.¶Despite their different architecture in the gallery forest, the M. bellicosus colonies could not completely compensate for the cooler environment and had a lower than optimal nest temperature. We speculate that this might be caused by the need for a sufficient surface for gas exchange. The gallery forest is a suboptimal habitat for M. bellicosus, because of lower than optimal nest temperatures. This might limit M. bellicosus to open stands in the gallery forest and may explain its surprisingly low abundance in this habitat.Type of Medium: Electronic ResourceURL: -
19Articles: DFG German National LicensesStaff View
ISSN: 1420-9098Keywords: Key words: Fungus, Macrotermes bellicosus, Macrotermitinae, metabolism, mound structure.Source: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Summary: Termites are well known for their ability to regulate the environment of their nest such as temperature and humidity. The influence of fluctuating ambient temperature and mound characteristics on mean nest temperature and daily fluctuation of nest temperature was analysed quantitatively in the fungus-cultivating, mound-building termite Macrotermes bellicosus (Macrotermitinae) in the savanna of the Comoé National Park (Côte d'Ivoire). Additionally, the nest temperatures of inhabited and uninhabited mounds were compared to analyse the contribution of ambient temperature to nest temperature in relation to metabolic heat production of the termites and their fungi. Mound structure alone resulted in a relatively constant nest temperature. Abiotic heat production via solar radiation alone yielded nest temperatures that corresponded to mean ambient temperatures. However, only the production of metabolic heat by the termites and the fungi increased these temperatures to the actual nest temperature. Therefore, and due to the high heat capacities of the mounds, large colonies (mound height above 2.0 m) had higher nest temperatures than smaller ones. Only large colonies attain constant nest temperatures of 30 °C that are largely independent from ambient temperatures and optimal for the growth and development of the termites and their fungi.Type of Medium: Electronic ResourceURL: -
20Articles: DFG German National LicensesStaff View
ISSN: 1420-9098Keywords: Key words: Savanna, termites, thermoregulation, termite mounds.Source: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Summary: Mounds of the fungus-cultivating termite Macrotermes bellicosus (Smeathman) in the Comoé-National Park (Ivory Coast, West Africa) differ in architecture between habitats. Mounds in the cooler, but thermally more stable gallery forest have been shown to be dome-shaped with thick walls, whereas mounds in the shrub savanna are more complex with many ridges and thin walls. In this investigation, we performed heating experiments to determine the thermal properties of the mounds in both habitats in order to test the hypothesis of a thermoregulatory significance of mound architecture. These experiments revealed that each mound had its characteristic individual heating up behavior that depends on its dimensions (height, surface, volume). In addition, habitat-specific traits were demonstrated: mounds of the gallery forest had higher thermal inertia, measured by the thermal capacity, than mounds of the shrub savanna. Thus, the dome-shaped mounds with thick walls in the gallery forest, with its suboptimal low temperatures, reduce loss of heat to the environment.Type of Medium: Electronic ResourceURL: