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  • 1
    Digitale Medien
    Digitale Medien
    Stabilization of smoothness priors time-varying autoregressive models (2000)
    Springer
    Circuits, systems and signal processing 19 (2000), S. 423-435 
    Details
    ISSN: 1531-5878
    Schlagwort(e): Time-varying autoregressive models ; stability ; smoothness priors ; Tihkonov regularization ; constrained optimization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract The stability of time-varying autoregressive (AR) models is an important issue in such applications as time-varying spectrum estimation and electroencephalography simulation and estimation. In some cases, such as time-varying spectrum estimation, the models that exhibit roots near unit moduli are difficult to use. Thus a tighter stability condition such as stability with a positive margin is needed. A time-varying AR model is stable with a positive margin if the moduli of the roots of the time-varying characteristic polynomial are somewhat less than unity for every time instant. Recently, a new method for the estimation of the time-varying AR models was introduced. This method is based on the interpretation of the underdetermined time-varying prediction equations as an ill-posed inverse problem that is solved by Tikhonov regularization. The method is referred to as the deterministic regression smoothness priors (DRSP) scheme. In this paper, a stabilization method in which the DRSP scheme is augmented with nonlinear stability constrainst is proposed. The problem is formulated so that stability with a positive margin can also be achieved. The problem is solved iteratively with an exterior point algorithm. The performance of the algorithm is studied with a simulation. It is shown that the proposed approach is well suited to stable modeling of signals containing narrowband transitions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01196156
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  • 2
    Digitale Medien
    Digitale Medien
    Stability of constant coefficient linear singular systems with delay (2000)
    Springer
    Circuits, systems and signal processing 19 (2000), S. 13-25 
    Details
    ISSN: 1531-5878
    Schlagwort(e): Singular systems ; delay ; consistency condition ; stability ; instability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract In this paper, the general class of singular systems with delay and linear constant coefficient singular systems with delay are discussed. First, several definitions of stability are presented for singular systems with delay, and general sufficient stability conditions and instability conditions are obtained. Second, stability and instability are analyzed for linear constant coefficient singular systems with delay.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01229989
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  • 3
    Digitale Medien
    Digitale Medien
    Biogeography, geographic variation and habitat preference in the Amazilia Hummingbird,Amazilia amazilia Lesson (Aves: Trochilidae), with notes on the status ofAmazilia alticola Gould (2000)
    Springer
    Journal of ornithology 141 (2000), S. 93-101 
    Details
    ISSN: 1439-0361
    Schlagwort(e): Biogeography ; geographic variation ; taxonomy ; Amazilia ; Trochilidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die vorliegende Studie stellt die Ergebnisse von Untersuchungen zur Biogeographie, geographischen Variation, Habitatwahl und Taxonomie der Lesson-Amazilie (Amazilia amazilia) vor. Das Taxon umfaßt gegenwärtig fünf Unterarten, die von W-Ecuador bis SW-Peru verbreitet sind und überwiegend submontane Lebensräume besiedeln. Die Ventralfärbung unterliegt klinaler Variation; weiße Gefiederanteile nehmen von nördlichen zu südlichen Populationen ab, rotbraune Partien dagegen zu. Eigenständige morphologisch-morphometrische Kennzeichen sowie Unterschiede in den Habitatpräferenzen und in der Gesangsstruktur rechtfertigen es, die bisherige UnterartA. a. alticola als Paraspezies (A. alticola, Loja-Amazilie) anzuerkennen. Der Vulgärname weist auf den rezenten Verbreitungsschwerpunkt in den südecuadorianischen Anden hin. Aufgrund der engen Verwandtschaft bildenA. amazilia undA. alticola sowie die in Kolumbien endemische ArtA. castaneiventris eine Superspezies.
    Notizen: Summary This paper reviews the biogeography, geographic variation, and habitat characteristics of the Amazilia Hummingbird (Amazilia amazilia). Based on morphological features, habitat preferences, and bioacoustics, I propose that the currently recognized subspeciesA. a. alticola should be regarded as a species distinct fromA. amazilia. Synapomorphic characters found in both taxa indicate membership of the same superspecies, together with the Colombian speciesA. castaneiventris. Considering the distributional focus ofA. alticola in the Andes of southern Ecuador, the English species name Loja Hummingbird is suggested.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01651776
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  • 4
    Digitale Medien
    Digitale Medien
    Calls of the Jungle Crow (Corvus macrorhynchos s.l.) as a taxonomic character (2000)
    Springer
    Journal of ornithology 141 (2000), S. 275-284 
    Details
    ISSN: 1439-0361
    Schlagwort(e): East Asia ; taxonomy ; species delimitation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Über die Gliederung der ostasiatischen Dickschnabelkrähen (Corvus macrorhynchos s.l.) in Biospezies besteht bisher keine einhellige Meinung. In dem großen Verbreitungsgebiet zwischen Indien, Japan und Timor werden gegenwärtig eine, zwei oder drei Arten anerkannt. Hier versuchen wir, in akustischen Merkmalen artanzeigende Merkmale zu finden. Eine Diskriminanzanalyse der Rufstruktur (76 Parameter) trennt dreiCorvus-Taxa (levaillantii undjaponensis aus der ‘macrorhynchos-Gruppe’,splendens) von der Südabdachung des Himalaya (Nepal, Kashmir) vollständig voneinander. BeiC. japonensis bleiben die trennenden Merkmale über große geographische Gebiete konstant. Die akustischen Unterschiede werden als taxonomisch relevant angesehen; sie zeigen Artgrenzen an. Folglich werden die Dickschnabelkrähen aus den Tief- und Hochlagen Nepals (Kontaktzone um 2 000 m) zwei Biospezies zugeordnet (C. japonensis undC. levaillantii), in Übereinstimmung mit morphologischen, ökologischen und parasitologischen Daten. Taxonomische Extrapolation der Befunde auf die Systematik anderer ‘macrorhynchos’-Populationen erscheint über die Rufstruktur (bis zum Fernen Osten Rußlands) und über Federling-Parasiten (Mallophaga) auf große Teile SO-Asiens möglich, bedarf aber für die stimmlichen Merkmale noch weiterer Klärung. Wahrscheinlich müssen immacrorhynchos-Komplex mindestens drei biologische Arten anerkannt werden (C. japonensis, C. levaillantii, C. macrorhynchos s. str.).
    Notizen: Summary A discriminant analysis of the call structure completely separates threeCorvus taxa (levaillantii andjaponensis of the ‘macrorhynchos group’,splendens) inhabiting the southern slopes of the Himalayas (Nepal, Kashmir). The acoustic differences are considered taxonomically relevant, indicating species boundaries. Therefore the Jungle Crows of lower and upper Nepal (contact zone at around 2,000 m) are assigned to two biospecies (C. japonensis andC. levaillantii), as is consistent with morphological, ecological and parasitological data. It appears possible to extrapolate the findings regarding call structure to the systematics of other ‘macrorhynchos’ populations as distant as the Russian Far East, and those regarding mallophagan parasites to large areas of SE Asia; regarding the vocal characteristics, however, further clarification is needed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02462237
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  • 5
    Digitale Medien
    Digitale Medien
    The Dynamics of a Fish Stock Exploited in Two Fishing Zones (2000)
    Springer
    Acta biotheoretica 48 (2000), S. 207-218 
    Details
    ISSN: 1572-8358
    Schlagwort(e): Dynamical population ; fishing efforts ; metapopulation ; time scales ; aggregation method ; equilibrium ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This work presents a specific stock-effort dynamical model. The stocks correspond to two populations of fish moving and growing between two fishery zones. They are harvested by two different fleets. The effort represents the number of fishing boats of the two fleets that operate in the two fishing zones. The bioeconomical model is a set of four ODE's governing the fishing efforts and the stocks in the two fishing areas. Furthermore, the migration of the fish between the two patches is assumed to be faster than the growth of the harvested stock. The displacement of the fleets is also faster than the variation in the number of fishing boats resulting from the investment of the fishing income. So, there are two time scales: a fast one corresponding to the migration between the two patches, and a slow time scale corresponding to growth. We use aggregation methods that allow us to reduce the dimension of the model and to obtain an aggregated model for the total fishing effort and fish stock of the two fishing zones. The mathematical analysis of the model is shown. Under some conditions, we obtain a stable equilibrium, which is a desired situation, as it leads to a sustainable harvesting equilibrium, keeping the stock at exploitable densities.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010208910738
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  • 6
    Digitale Medien
    Digitale Medien
    Performance analysis of a slotted-ALOHA protocol on a capture channel with fading (2000)
    Springer
    Queueing systems 34 (2000), S. 1-35 
    Details
    ISSN: 1572-9443
    Schlagwort(e): multiple access ; CDMA ; rates of convergence ; stability ; functional limit theorems ; transient analysis ; Markov-modulated capture channel
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract We consider the slotted ALOHA protocol on a channel with a capture effect. There are M 〈 ∞ users each with an infinite buffer. If in a slot, i packets are transmitted, then the probability of a successful reception of a packet is q i. This model contains the CDMA protocols as special cases. We obtain sufficient rate conditions, which are close to necessary for stability of the system, when the arrival streams are stationary ergodic. Under the same rate conditions, for general regenerative arrival streams, we obtain the rates of convergence to stationarity, finiteness of stationary moments and various functional limit theorems. Our arrival streams contain all the traffic models suggested in the recent literature, including the ones which display long range dependence. We also obtain bounds on the stationary moments of waiting times which can be tight under realistic conditions. Finally, we obtain several results on the transient performance of the system, e.g., first time to overflow and the limits of the overflow process. We also extend the above results to the case of a capture channel exhibiting Markov modulated fading. Most of our results and proofs will be shown to hold also for the slotted ALOHA protocol without capture.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1019192600091
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  • 7
    Digitale Medien
    Digitale Medien
    Normal Form Invariants Around Spin-orbit Periodic Orbits (2000)
    Springer
    Celestial mechanics and dynamical astronomy 78 (2000), S. 227-241 
    Details
    ISSN: 1572-9478
    Schlagwort(e): stability ; normal form ; spin-orbit resonance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We consider a model of spin-orbit interaction, describing the motion of an oblate satellite rotating about an internal spin-axis and orbiting about a central planet. The resulting second order differential equation depends upon the parameters provided by the equatorial oblateness of the satellite and its orbital eccentricity. Normal form transformations around the main spin-orbit resonances are carried out explicitly. As an outcome, one can compute some invariants; the fact that these quantities are not identically zero is a necessary condition to prove the existence of nearby periodic orbits (Birkhoff fixed point theorem). Moreover, the nonvanishing of the invariants provides also the stability of the spin-orbit resonances, since it guarantees the existence of invariant curves surrounding the periodic orbit.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1011161605935
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  • 8
    Digitale Medien
    Digitale Medien
    A New ADI Scheme for Solving Three-Dimensional Parabolic Equations with First-Order Derivatives and Variable Coefficients (2000)
    Springer
    Journal of computational analysis and applications 2 (2000), S. 293-308 
    Details
    ISSN: 1572-9206
    Schlagwort(e): parabolic equations ; ADI scheme ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract An ADI scheme for solving three-dimensional parabolic equations withfirst-order derivatives and variable coefficients has been developed basedon our previous papers and the idea of the modified upwind differencescheme. This ADI scheme is second-order accurate and unconditionallystable. Further, a small parameter can be chosen which makes it suitablefor simulating fast-transient phenomena or for computations on fine spatialmeshes. The method is illustrated with numerical examples.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010108620966
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  • 9
    Digitale Medien
    Digitale Medien
    A Multiclass Feedback Queueing Network with a Regular Skorokhod Problem (2000)
    Springer
    Queueing systems 36 (2000), S. 327-349 
    Details
    ISSN: 1572-9443
    Schlagwort(e): multiclass networks ; networks with feedback ; Skorokhod Problem ; Skorokhod Mapping ; Lipschitz continuity ; stability ; load conditions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract We consider a four-class two-station network with feedback, with fluid inputs and a head-of-the-line generalized processor sharing discipline at each station. We derive the Skorokhod Problem associated with the network and obtain algebraic sufficient conditions for Lipschitz continuity of the associated Skorokhod Map. This provides the first example of a multiclass network with feedback for which the associated Skorokhod Problem has been proved to be regular. As an elementary application, we show that under the conditions which guarantee Lipschitz continuity the network is stable if and only if the usual load conditions apply.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1011037419624
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  • 10
    Digitale Medien
    Digitale Medien
    Bifurcation Phenomena from Standing Pulse Solutions in Some Reaction-Diffusion Systems (2000)
    Springer
    Journal of dynamics and differential equations 12 (2000), S. 117-167 
    Details
    ISSN: 1572-9222
    Schlagwort(e): singular perturbation ; standing pulses ; stability ; Hopf bifurcation ; reaction-diffusion system
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract Bifurcation phenomena from standing pulse solutions of the problem $$\varepsilon \tau u_t = \varepsilon ^2 u_{xx} + f(u,v),{\text{ }}v_t = v_{xx} + g(u,v)$$ is considered. ε(〉0) is a sufficiently small parameter and τ is a positive one. It is shown that there exist two types of destabilization of standing pulse solutions when τ decreases. One is the appearance of travelling pulse solutions via the static bifurcation and the other is that of in-phase breathers via the Hopf bifurcation. Furthermore which type of destabilization occurs first with decreasing τ is discussed for the piecewise linear nonlinearities f and g.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009098719440
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  • 11
    Digitale Medien
    Digitale Medien
    Activity and stability of Cu/ZnO/Al2O3 catalyst promoted with B2O3 for methanol synthesis (2000)
    Springer
    Catalysis letters 68 (2000), S. 55-58 
    Details
    ISSN: 1572-879X
    Schlagwort(e): promoting effect ; B2O3 ; Cu/ZnO/Al2O3 catalyst ; methanol synthesis ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The addition of B2O3 to a Cu/ZnO/Al2O3 catalyst increased the activity of the catalyst for methanol synthesis after an induction period during the reaction. The stability of the B2O3-containing Cu/ZnO/Al2O3 catalyst was greatly improved by the addition of a small amount of colloidal silica to the catalyst.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1019010831562
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  • 12
    Digitale Medien
    Digitale Medien
    Stability and excitation of potassium promoter in iron catalysts – the role of KFeO2 and KAlO2 phases (2000)
    Springer
    Catalysis letters 67 (2000), S. 129-134 
    Details
    ISSN: 1572-879X
    Schlagwort(e): potassium desorption ; stability ; excitation ; iron catalyst ; Rydberg atoms
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Well‐characterized catalyst model compounds of KAlO2 and KFeO2 are investigated by thermal desorption of potassium from the material. The desorbing fluxes of ions, atoms and highly excited states (field ionizable Rydberg states) were studied with surface and field ionization detectors in a vacuum apparatus. From the Arrhenius plots the activation energies for desorption of K and K+ were determined. The chemical state of potassium at the surfaces is concluded to be: ionic on KAlO2 (with the K desorption barrier of 1.76 eV) and covalent on KFeO2 (barrier of 2.73 eV). These results agree with the data obtained earlier for industrial catalysts for ammonia and styrene production. They are interpreted in terms of the Schottky cycle, which is completed for KAlO2 and fails for KFeO2. This failure indicates a non‐equilibrium desorption process. K Rydberg states are only found to desorb from KFeO2, in agreement with the suggestion that such states in some way are responsible for the catalytic activity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1019013504729
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  • 13
    Digitale Medien
    Digitale Medien
    Stability of Linear Inequality Systems Measured by the Hausdorff Metric (2000)
    Springer
    Set-valued analysis 8 (2000), S. 253-266 
    Details
    ISSN: 1572-932X
    Schlagwort(e): Hausdorff metric ; linear inequality systems ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract In this paper, we propose a Hausdorff metric to measure the “distance” between two linear inequality systems on a real normed space X. For this topology, which comes through a pseudo-metric in the set Σ of linear inequality systems, the closedness of the feasible set mapping is studied, and at the same time a characterization of the stability of the subset Σ c of consistent sytems is given.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008701026782
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  • 14
    Digitale Medien
    Digitale Medien
    Stability Properties of a Bond Portfolio Management Problem (2000)
    Springer
    Annals of operations research 99 (2000), S. 251-265 
    Details
    ISSN: 1572-9338
    Schlagwort(e): stochastic programming ; bond portfolio management ; interest ratescenarios ; stability ; sensitivity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik , Wirtschaftswissenschaften
    Notizen: Abstract The bond portfolio management problem is formulated as a multiperiod two-stage or multistage stochastic program based on interest rate scenarios. These scenarios depend on the available market data, on the applied estimation and sampling techniques, etc., and are used to evaluate coefficients of the resulting large scale mathematical program. The aim of the contribution is to analyze stability and sensitivity of this program on small changes of the coefficients – the (scenario dependent) values of future interest rates and prices. We shall prove that under sensible assumptions, the scenario subproblems are stable linear programs and that also the optimal first-stage decisions and the optimal value of the considered stochastic program possess acceptable continuity properties.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1019275817688
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  • 15
    Digitale Medien
    Digitale Medien
    Destabilization for quasivariational inequalities of reaction-diffusion type (2000)
    Springer
    Applications of mathematics 45 (2000), S. 161-176 
    Details
    ISSN: 1572-9109
    Schlagwort(e): reaction-diffusion system ; unilateral conditions ; quasivariational inequality ; Leray-Schauder degree ; eigenvalue ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract We consider a reaction-diffusion system of the activator-inhibitor type with unilateral boundary conditions leading to a quasivariational inequality. We show that there exists a positive eigenvalue of the problem and we obtain an instability of the trivial solution also in some area of parameters where the trivial solution of the same system with Dirichlet and Neumann boundary conditions is stable. Theorems are proved using the method of a jump in the Leray-Schauder degree.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1023033910657
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  • 16
    Digitale Medien
    Digitale Medien
    Diagonally implicit Runge–Kutta methods for 3D shallow water applications (2000)
    Springer
    Advances in computational mathematics 12 (2000), S. 229-250 
    Details
    ISSN: 1572-9044
    Schlagwort(e): numerical analysis ; shallow water problems ; DIRK methods ; stability ; 65L06 ; 65L20 ; 65M12 ; 65M20
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract We construct A‐stable and L‐stable diagonally implicit Runge–Kutta methods of which the diagonal vector in the Butcher matrix has a minimal maximum norm. If the implicit Runge–Kutta relations are iteratively solved by means of the approximately factorized Newton process, then such iterated Runge–Kutta methods are suitable methods for integrating shallow water problems in the sense that the stability boundary is relatively large and that the usually quite fine vertical resolution of the discretized spatial domain is not involved in the stability condition.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1018969203026
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  • 17
    Digitale Medien
    Digitale Medien
    On the Robustness of Gaussian Elimination with Partial Pivoting (2000)
    Springer
    BIT 40 (2000), S. 62-73 
    Details
    ISSN: 1572-9125
    Schlagwort(e): Gaussian elimination ; stability ; pivoting
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract It has been recently shown that large growth factors might occur in Gaussian Elimination with Partial Pivoting (GEPP) also when solving some plausibly natural systems. In this note we argue that this potential problem could be easily solved, with much smaller risk of failure, by very small (and low cost) modifications of the basic algorithm, thus confirming its inherent robustness. To this end, we first propose an informal model with the goal of providing further support to the comprehension of the stability properties of GEPP. We then report the results of numerical experiments that confirm the viewpoint embedded in the model. Basing on the previous observations, we finally propose a simple scheme that could be turned into (even more) accurate software for the solution of linear systems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1022314201484
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  • 18
    Digitale Medien
    Digitale Medien
    Runge-Kutta Methods for the Numerical Solution of Stiff Semilinear Systems (2000)
    Springer
    BIT 40 (2000), S. 611-639 
    Details
    ISSN: 1572-9125
    Schlagwort(e): Runge-Kutta methods ; stability ; convergence ; stiff problems
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract This paper studies the stability and convergence properties of general Runge-Kutta methods when they are applied to stiff semilinear systems y′(t) = J(t)y(t) + g(t, y(t)) with the stiffness contained in the variable coefficient linear part. We consider two assumptions on the relative variation of the matrix J(t) and show that for each of them there is a family of implicit Runge-Kutta methods that is suitable for the numerical integration of the corresponding stiff semilinear systems, i.e. the methods of the family are stable, convergent and the stage equations possess a unique solution. The conditions on the coefficients of a method to belong to these families turn out to be essentially weaker than the usual algebraic stability condition which appears in connection with the B-stability and convergence for stiff nonlinear systems. Thus there are important RK methods which are not algebraically stable but, according to our theory, they are suitable for the numerical integration of semilinear problems. This paper also extends previous results of Burrage, Hundsdorfer and Verwer on the optimal convergence of implicit Runge-Kutta methods for stiff semilinear systems with a constant coefficients linear part.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1022332200092
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  • 19
    Digitale Medien
    Digitale Medien
    Stochastic Methods for Ill-Posed Problems (2000)
    Springer
    BIT 40 (2000), S. 226-240 
    Details
    ISSN: 1572-9125
    Schlagwort(e): Stochastic differential equations ; regularisation ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract This paper is devoted to the numerical analysis of ill-posed problems of evolution equations in Banach spaces using certain classes of stochastic one-step methods. The linear stability properties of these methods are studied. Regularisation is given by the choice of the regularisation parameter as α = $$\sqrt {\tau _n }$$ , where τ n is the stepsize and provides the convergence on smooth initial data. The case of the approximation of well-posed problems is also considered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1022386822865
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  • 20
    Digitale Medien
    Digitale Medien
    Hydraulic analysis of free-surface flows with solidification (2000)
    Springer
    Archive of applied mechanics 70 (2000), S. 17-29 
    Details
    ISSN: 1432-0681
    Schlagwort(e): Key words free-surface flow ; solidification ; strip casting ; steady state ; nonuniqueness ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Summary The paper is concerned with a one-dimensional analysis of plane open-channel flow with continuous solidification. The process is of relevance for recent developments in the casting of steel and other metals. The bottom of the channel consists of a rotating casting roll and a horizontal cooling table, where the solidified material is withdrawn with given velocity. The study is restricted to the region downstream of the top of the casting roll. Surface tension is neglected. In the main part of the analysis inviscid fluid flow is considered since the Reynolds number is very large in the applications. It is found that the steady-state solutions are nonunique in a certain parameter range. In addition to a continuous solution, there are two solutions including hydraulic jumps, with one hydraulic jump being located on the casting roll, the other one on the cooling table. Regarding the stability of the non unique solutions, the evolution of disturbances is investigated numerically as an initial-value problem. It is concluded that the hydraulic jump on the cooling table is unstable, while the other discontinuous solution as well as the continuous solution are stable for sufficiently small disturbances. Which stable solution is attained in the steady state, depends on the history of the process. Friction at the liquid/solid interface is taken into account in the last part of the analysis. A constant friction coefficient is assumed. It is found that the history of the process determines the steady-state solution if, and only if, the friction coefficient is sufficiently small. For larger values of the friction coefficient, the steady-state solution is unique and independent of the history of the transient process. Furthermore, for sufficiently large friction coefficients, stable hydraulic jumps are found, in contrast to the inviscid case, also on the cooling table.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004199900031
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  • 21
    Digitale Medien
    Digitale Medien
    Questioning species realities (2000)
    Springer
    Conservation genetics 1 (2000), S. 67-76 
    Details
    ISSN: 1572-9737
    Schlagwort(e): mitochondrial DNA ; phylogeny ; phylogeography ; speciation ; species concepts ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010133721121
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  • 22
    Digitale Medien
    Digitale Medien
    Concerning a Technique for Increasing Stability of Climbing Robots (2000)
    Springer
    Journal of intelligent and robotic systems 27 (2000), S. 195-209 
    Details
    ISSN: 1573-0409
    Schlagwort(e): wall-climbing robot ; electromagnetic grippers ; stability ; additional support element ; sliding and turning over conditions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik , Maschinenbau
    Notizen: Abstract Legged-climbing robot is considered. Each foot of the robot has an electromagnet system for robot"s holding on a metal surface. This surface can be both vertical and inclined, including negative slope. Analytical calculation of robot stability under turn over or sliding conditions has been made. Critical slopes have been determined. One of these slopes corresponds to minimal reserve of robot stability towards sliding and another to minimal reserve of robot stability towards turning-over. As total reserve of stability of a robot is always equal to the minimal one of these reserves. Additional support elements of elastic material with high coefficient of friction, along with electromagnet, allows to increase minimal reserve of robot stability towards sliding. The use of such support elements leads to redistributing force of normal support reaction between electromagnet (which surface has low coefficient of friction) and additional support element (which surface has high coefficient of friction). It is just what leads to increasing the total friction force and as a consequence to increasing of minimal reserve of robot stability towards sliding.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008158332368
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  • 23
    Digitale Medien
    Digitale Medien
    Perron–Frobenius Theory and Symmetry of Solutions to Nonlinear PDE's (2000)
    Springer
    Letters in mathematical physics 53 (2000), S. 313-320 
    Details
    ISSN: 1573-0530
    Schlagwort(e): partial differential equations ; nonlinearities ; symmetries ; stability ; minimization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik , Physik
    Notizen: Abstract We suggest a simple but general method of establishing symmetry properties of stable solutions of nonlinear elliptic equations. The method relies on characterization of symmetry breaking with a help of zero modes and on a generalization of the Perron–Frobenius theory.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1007622208894
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  • 24
    Digitale Medien
    Digitale Medien
    Stability of Attractive Bose–Einstein Condensates (2000)
    Springer
    Journal of statistical physics 101 (2000), S. 731-746 
    Details
    ISSN: 1572-9613
    Schlagwort(e): attractive Bose–Einstein condensates ; nonlinear Schrödinger equation ; stability ; ground state ; variational arguments
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We propose the critical nonlinear Schrödinger equation with a harmonic potential as a model of attractive Bose–Einstein condensates. By an elaborate mathematical analysis we show that a sharp stability threshold exists with respect to the number of condensate particles. The value of the threshold agrees with the existing experimental data. Moreover with this threshold we prove that a ground state of the condensate exists and is orbital stable. We also evaluate the minimum of the condensate energy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1026437923987
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  • 25
    Digitale Medien
    Digitale Medien
    Building on Bedrock: William Steel Creighton and the Reformation of Ant Systematics, 1925–1970 (2000)
    Springer
    Journal of the history of biology 33 (2000), S. 27-70 
    Details
    ISSN: 1573-0387
    Schlagwort(e): ants ; E. O. Wilson ; Ernst Mayr ; systematics ; Systematics and the Origin of Species ; taxonomy ; William L. Brown ; William Morton Wheeler ; William Steel Creighton
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geschichte
    Notizen: Abstract Ideas about the natural world are intertwined with the personalities, practices, and the workplaces of scientists. The relationships between these categories are explored in the life of the taxonomist William Steel Creighton. Creighton studied taxonomy under William Morton Wheeler at Harvard University. He took the rules he learned from Wheeler out of the museum and into the field. In testing the rules against a new situation, Creighton found them wanting. He sought a new set of taxonomic principles, one he eventually found in Ernst Mayr's Systematics and the Origin of Species. Mayr's ideas tied together a number of themes running through Creighton's life: the need for a revised taxonomy, the emphasis on fieldwork, and the search for a new power center for ant taxonomy after Wheeler died. Creighton's adoption of Mayr's ideas as part of his professional identity also had very real implications for his career path: field studies required long and intensive studies, and Creighton would always be a slow worker. His method of taxonomy contrasted sharply not only with Wheeler's but also with two of his younger colleagues, William L. Brown and E. O. Wilson, who took over Wheeler's spot at Harvard in 1950. The disputes between these men over ant taxonomy involved, in addition to questions of technical interest, questions about where and how best to do taxonomy and who could speak withthe most authority. Creighton's story reveals how these questions are interrelated. The story also reveals the importance of Mayr's book for changes occurring in taxonomy in the middle of the twentieth century.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004712911037
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  • 26
    Digitale Medien
    Digitale Medien
    On the Stability of Functional Equations and a Problem of Ulam (2000)
    Springer
    Acta applicandae mathematicae 62 (2000), S. 23-130 
    Details
    ISSN: 1572-9036
    Schlagwort(e): stability ; functional equations ; Cauchy difference ; semigroup ; inequalities ; approximate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract In this paper, we study the stability of functional equations that has its origins with S. M. Ulam, who posed the fundamental problem 60 years ago and with D. H. Hyers, who gave the first significant partial solution in 1941. In particular, during the last two decades, the notion of stability of functional equations has evolved into an area of continuing research from both pure and applied viewpoints. Both classical results and current research are presented in a unified and self-contained fashion. In addition, related problems are investigated. Some of the applications deal with nonlinear equations in Banach spaces and complementarity theory.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006499223572
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  • 27
    Digitale Medien
    Digitale Medien
    Debonding of the interface as 'crack arrestor' (2000)
    Springer
    International journal of fracture 105 (2000), S. 57-79 
    Details
    ISSN: 1573-2673
    Schlagwort(e): Interface toughness ; interface debonding ; stability ; adhesive interface ; bimaterial.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract In this paper, we studied the interface debonding when a crack perpendicularly approaches an interface between two dissimilar elastic materials. An interface toughness law was first defined according to an adhesive model governing the interface fracture. By analysing the interaction between the normally approaching crack and the interface crack and by tacking account of the adhesive forces at ends of the interfacial crack, a model for studying the interface debonding and the debonding stability was established. It is observed that the interface debonding toughness depends strongly on the mixed mode locally produced over the plastic adhesive zone of the interface. Moreover, the interface debonding may be unstable, i.e. the interface debonding length may jump from an initial value to a certain final value under critical remote loading. This jump may be surprisedly important in certain cases. These results agree with the experimental works gathered so far and can be used to explain the mechanism of 'crack arrestor' formed by an interface.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1007603809972
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  • 28
    Digitale Medien
    Digitale Medien
    Effects of Ca2+ on the Activity and Stability of Methanol Dehydrogenase (2000)
    Springer
    The protein journal 19 (2000), S. 469-473 
    Details
    ISSN: 1573-4943
    Schlagwort(e): Methanol dehydrogenase ; Ca2+ ; binding ; activity ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The effects of exogenously added Ca2+ on the enzymatic activity and structural stability of methanol dehydrogenase were studied for various Ca2+ concentrations. Methanol dehydrogenase activity increased significantly with increasing concentration of Ca2+, approaching saturation at 200 mM Ca2+. The effect of Ca2+ on the activation of MDH was time dependent and Ca2+ specific and was due to binding of the metal ions to the enzyme. Addition of increasing concentration of Ca2+ caused a decrease of the intrinsic tryptophan fluorescence intensity in a concentration-dependent manner to a minimum at 200 mM, but with no change in the fluorescence emission maximum wavelength or the CD spectra. The results revealed that the activation of methanol dehydrogenase by Ca2+ occurred concurrently with the conformational change. In addition, exogenously bound Ca2+ destabilized MDH. The potential biological significance of these results is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1026597314542
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  • 29
    Digitale Medien
    Digitale Medien
    Two new species and one new variety of Agaricales from central Honshu, Japan (2000)
    Springer
    Mycoscience 41 (2000), S. 15-23 
    Details
    ISSN: 1618-2545
    Schlagwort(e): Agaricales ; Clitocybe trogioides var.odorifera ; Gerronema nemorale ; Psathyrella cineraria ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Two new species and one new variety of Agaricales are described and illustrated from central Honshu, Japan:Clitocybe trogioides var.odorifera var. nov. (subgenusCystoclitus sectionCystoclitus), forming white, infundibuliform basidiomata, was collected from leaf litter in theQuercus-Pasania forests;Gerronema nemorale sp. nov. (sectionXanthophylla), forming small, olivaceous, omphalinoid basidiomata, was found on dead fallen twigs in theQuercus-Pasania forests;Psathyrella cineraria sp. nov. (subgenusMycophylla sectionArgillosporae), forming basidiomata covered by detersile, dark grey, fibrillose-squamulose veil, was found on decayed wood ofQuercus myrsinaefolia.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02464381
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  • 30
    Digitale Medien
    Digitale Medien
    Diaporthe kyushuensis sp. nov., the teleomorph of the causal fungus of grapevine swelling arm in Japan, and its anamorphPhomopsis vitimegaspora (2000)
    Springer
    Mycoscience 41 (2000), S. 111-114 
    Details
    ISSN: 1618-2545
    Schlagwort(e): Diaporthe kyushuensis ; grapevine swelling arm ; Phomopsis vitimegaspora ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Diaporthe kyushuensis sp. nov. is described and named as the teleomorph of causal fungus of grapevine swelling arm. The anamorph of the fungus isPhomopsis vitimegaspora.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02464318
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  • 31
    Digitale Medien
    Digitale Medien
    Cronartium orientale, sp. nov., segregation of the pine gall rust in eastern Asia fromCronartium quercuum (2000)
    Springer
    Mycoscience 41 (2000), S. 115-122 
    Details
    ISSN: 1618-2545
    Schlagwort(e): distribution ; Pinus ; Quercus ; taxonomy ; Uredinales
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The Asian pine gall rust, which has hitherto been assigned toCronartium quercuum distributed in North America, is described asC. orientale, sp. nov. The spermogonial and aecial states occur on hard pines, and the uredinial and telial states occur on various oaks.Cronartium orientale has globose, almost hyaline basidiospores in contrast to the ellipsoid, yellow-orange ones of North AmericanC. quercuum s.l. Characteristics of the new rust species in morphology, DNA analysis, and host alternation are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02464319
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  • 32
    Digitale Medien
    Digitale Medien
    A newLeptographium species associated withTomicus piniperda in south-western China (2000)
    Springer
    Mycoscience 41 (2000), S. 573-578 
    Details
    ISSN: 1618-2545
    Schlagwort(e): China ; Leptographium ; morphology ; taxonomy ; Tomicus piniperda
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Tomicus species (Coleoptera: Scolytidae) are serious pests of pines with a wide distribution in Europe, Asia and America. In Yunnan, south-western China,T. piniperda has destroyed more than 0.5 million ha ofPinus yunnanensis in the past 15 years. A blue stain fungus belonging to the genusLeptographium is associated with both the shoot-feeding and trunk-attacking stages of the beetle's life cycle. The fungus is morphologically similar to the anamorph ofOphiostoma crassivaginatum and toL. pyrinum, which are both characterised by short robust conidiophores and hyphae covered by a granular layer. Both these species have been isolated from conifers and are associated with insects. After comparing the fungus fromT. piniperda with similarLeptographium species, using light and scanning electron microscopy, we concluded that it represents a new taxon, which is described here asL. yunnanense sp. nov.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02460923
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  • 33
    Digitale Medien
    Digitale Medien
    Bifurcations of a cantilevered pipe conveying steady fluid with a terminal nozzle (2000)
    Springer
    Acta mechanica Sinica 16 (2000), S. 264-272 
    Details
    ISSN: 1614-3116
    Schlagwort(e): nonlinear dynamics ; bifurcation ; stability ; fluid-solid interaction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Physik
    Notizen: Abstract This paper studies interactions of pipe and fluid and deals with bifurcations of a cantilevered pipe conveying a steady fluid, clamped at one end and having a nozzle subjected to nonlinear constraints at the free end. Either the nozzle parameter or the flow velocity is taken as a variable parameter. The discrete equations of the system are obtained by the Ritz-Galerkin method. The static stability is studied by the Routh criteria. The method of averaging is employed to examine the analytical results and the chaotic motions. Three critical values are given. The first one makes the system lose the static stability by pitchfork bifurcation. The second one makes the system lose the dynamical stability by Hopf bifurcation. The third one makes the periodic motions of the system lose the stability by doubling-period bifurcation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02487667
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  • 34
    Digitale Medien
    Digitale Medien
    Long-term monitoring of benthic macroinvertebrate community structure: a perspective from a Colorado river* (2000)
    Springer
    Aquatic ecology 34 (2000), S. 261-278 
    Details
    ISSN: 1573-5125
    Schlagwort(e): discharge effects on lotic invertebrates ; disturbance ; persistence ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Temporal and spatial trends were examined in benthic macroinvertebrate and physical-chemical data collected for at least ten years at ten sites along the plains reach of the Cache la Poudre River, Colorado, USA. A distinct longitudinal environment gradient was found as many of the water chemistry parameter levels changed downstream from the reference site. Seasonal Kendall analyses on individual sites indicated that several chemical parameters, including conductivity, un-ionized NH3-N and NO2-N have increased since the beginning of the study within most sites. Levels of some parameters (e.g., dissolved oxygen, un-ionized NH3-N) violated aquatic life standards a few times during the study. Over 175 taxa of macroinvertebrates (primarily insects) were collected in the study reach from 1981–1996. Results from detrended correspondence analyses (DCA) on macroinvertebrate data indicated that this stretch of the river exhibited little longitudinal change beyond the two farthest upstream sites. There was a decline in macroinvertebrate density and total number of taxa within most individual sites during 1983–1984, corresponding with the highest recorded discharge in 75 years (1983) and a prolonged, heavy spring runoff in 1984. Taxa richness and density recovered to pre-1983 levels within a few months to a year following the high flows at most sites. These findings suggested that the macroinvertebrate assemblages had low resistance to disturbance, but high resilience. However, the results from DCAs and Kendall's Coefficient of Concordance (W) on individual sites for the entire study period suggested a similar macroinvertebrate community structure through time. It would appear that the composition and abundance of the lotic macroinvertebrate assemblages in the Poudre River has remained relatively constant over the long-term. This has occurred even with some potentially negative changes in water chemistry and increased urban development.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009989510721
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  • 35
    Digitale Medien
    Digitale Medien
    Numerical solutions for a coupled non-linear oscillator (2000)
    Springer
    Journal of mathematical chemistry 28 (2000), S. 325-340 
    Details
    ISSN: 1572-8897
    Schlagwort(e): numerical method ; stability ; Hopf bifurcation ; coupled oscillator
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Mathematik
    Notizen: Abstract A second-order accurate numerical method has been proposed for the solution of a coupled non-linear oscillator featuring in chemical kinetics. Although implicit by construction, the method enables the solution of the model initial-value problem (IVP) to be computed explicitly. The second-order method is constructed by taking a linear combination of first-order methods. The stability analysis of the system suggests the existence of a Hopf bifurcation, which is confirmed by the numerical method. Both the critical point of the continuous system and the fixed point of the numerical method will be seen to have the same stability properties. The second-order method is more competitive in terms of numerical stability than some well-known standard methods (such as the Runge–Kutta methods of order two and four).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1011025104111
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  • 36
    Digitale Medien
    Digitale Medien
    Species, Demes, and the Omega Taxonomy: Gilmour and The NewSystematics (2000)
    Springer
    Biology and philosophy 15 (2000), S. 349-388 
    Details
    ISSN: 1572-8404
    Schlagwort(e): cline ; definition ; deme ; evolutionary synthesis ; experimental taxonomy ; J. Heslop-Harrison ; J.S. Huxley ; J.S.L. Gilmour ; nominalism ; systematics ; Systematics Association ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Philosophie
    Notizen: Abstract The word ``deme'' was coined by the botanists J.S.L. Gilmour and J.W.Gregor in 1939, following the pattern of J.S. Huxley's ``cline''. Its purposewas not only to rationalize the plethora of terms describing chromosomaland genetic variation, but also to reduce hostility between traditionaltaxonomists and researchers on evolution, who sometimes scorned eachother's understanding of species. A multi-layered system of compoundterms based on deme was published by Gilmour and J. Heslop-Harrison in1954 but not widely used. Deme was adopted with a modified meaning byzoologists leading the evolutionary synthesis – Huxley, Simpson, Wright,and Mayr. Connections are shown between Gilmour's ideas around definingthe deme, his role in founding the Systematics Association, and his chapter``Taxonomy and Philosophy'' in the book The New Systematics. Thishistorical episode raises questions about the role of carefully-definedwords in scientific practice.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006774217770
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  • 37
    Digitale Medien
    Digitale Medien
    A new variety ofCortinarius elatior from Japan (2000)
    Springer
    Mycoscience 41 (2000), S. 87-89 
    Details
    ISSN: 1618-2545
    Schlagwort(e): Cortinarius elatior var.albipes ; Cortinarius Sect.Defibulati ; new variety ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cortinarius elatior var.albipes var. nov., found in the deciduous forest is described and illustrated. It is distinguished from the type variety by having a white stipe and longer spores. The differences betweenCortinarius elatior var.albipes and similar taxa are briefly discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02464390
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  • 38
    Digitale Medien
    Digitale Medien
    Ceratostomella hyalocoronata, a new pyrenomycete from a stream in southern China (2000)
    Springer
    Mycoscience 41 (2000), S. 167-169 
    Details
    ISSN: 1618-2545
    Schlagwort(e): East Asia ; freshwater fungi ; taxonomy ; tropical mycology ; Xylariales
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Ceratostomella hyalocoronata is described and illustrated as a new species from old decaying wood immersed in a stream in Guangdong Province, southern China. It is compared toC. hyalostoma, a temperate terrestrial species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02464327
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  • 39
    Digitale Medien
    Digitale Medien
    Three new marine ascomycetes from driftwood in Australia sand dunes (2000)
    Springer
    Mycoscience 41 (2000), S. 379-388 
    Details
    ISSN: 1618-2545
    Schlagwort(e): arenicolous ; marine fungi ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Caryospora australiensis sp. nov.,Platystomum scabridisporum sp. nov. andSavoryella melanospora sp. nov. are described from driftwood collected from a sand dune at Rye, on the Mornington Peninsula Nature Park, Victoria, Australia. These species are compared with other taxa in these and related genera.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02463951
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  • 40
    Digitale Medien
    Digitale Medien
    Two underscribed heterobasidiomycetes from Ontario (2000)
    Springer
    Mycoscience 41 (2000), S. 371-377 
    Details
    ISSN: 1618-2545
    Schlagwort(e): Platygloea ; Platygloeales ; Sigmogloea ; taxonomy ; Tremellales
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Specimens of two heterobasidiomycetous species, collected in Ontario and studied respectively by H. S. Jackson and R. F. Cain, are described as new; they arePlatygloea jacksonii andSigmogloea tremelloidea. P. jacksonii is characterized by small basidia and basidiospores and by sympodially developing conidia.Sigmogloea tremelloidea is an anomalous taxon with cylindric, mostly transversely septate (“auricularioid”) basidia, but some features suggest a possible relationship to the Tremellales.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02463950
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  • 41
    Digitale Medien
    Digitale Medien
    Cortinarius purpurascens var.largusoides andCortinarius herpeticus var.fageticola new to Japan (2000)
    Springer
    Mycoscience 41 (2000), S. 407-410 
    Details
    ISSN: 1618-2545
    Schlagwort(e): Cortinarius purpurascens var.largusoides ; Cortinarius herpeticus var.fageticola ; Cortinarius Sect.Scauri ; mycoflora ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Two species ofCortinarius Sect.Scauri collected in forests ofQuercus serrata andQ. mongolica var.grosseserrata, Q. serrata andFagus crenata, orQ. mongolica var.grosseserrata andF. crenata in Niigata prefecture were identified asCortinarius purpurascens var.largusoides andC. herpeticus var.fageticola, new to Japan. Macro- and microscopical descriptions of each species are given.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02463956
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  • 42
    Digitale Medien
    Digitale Medien
    1,3-Dihydrobenzo[c]thienylium (thiophthalylium) salts. (Review) (2000)
    Springer
    Chemistry of heterocyclic compounds 36 (2000), S. 115-133 
    Details
    ISSN: 1573-8353
    Schlagwort(e): thiophthalylium salts ; methods of preparation ; structure ; stability ; reactivity ; electrophilic properties
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Methods of preparation, chemical reactions, the structures and reactivity of thiophthalylium ions are reviewed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02283539
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  • 43
    Digitale Medien
    Digitale Medien
    Solving A $$\underline x $$ = $$\underline b $$ Using a Modified Conjugate Gradient Method Based on Roots of A (2000)
    Springer
    Journal of scientific computing 15 (2000), S. 441-456 
    Details
    ISSN: 1573-7691
    Schlagwort(e): modified conjugate gradient method ; conjugate gradient method ; Krylov space ; convergence rate ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract We consider the modified conjugate gradient procedure for solving A $$\underline x $$ = $$\underline b $$ in which the approximation space is based upon the Krylov space associated with A 1/p and $$\underline b $$ , for any integer p. For the square-root MCG (p=2) we establish a sharpened bound for the error at each iteration via Chebyshev polynomials in $$\sqrt A$$ . We discuss the implications of the quickly accumulating effect of an error in $$\sqrt A$$ $$\underline b $$ in the initial stage, and find an error bound even in the presence of such accumulating errors. Although this accumulation of errors may limit the usefulness of this method when $$\sqrt A$$ $$\underline b $$ is unknown, it may still be successfully applied to a variety of small, “almost-SPD” problems, and can be used to jump-start the conjugate gradient method. Finally, we verify these theoretical results with numerical tests.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1011132730828
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  • 44
    Digitale Medien
    Digitale Medien
    Associative Memories in Infinite Dimensional Spaces (2000)
    Springer
    Neural processing letters 12 (2000), S. 129-144 
    Details
    ISSN: 1573-773X
    Schlagwort(e): associative memory ; dynamical systems ; Glauber dynamics ; Hopfield model ; infinite dimensional state space ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract A generalization of the Little–Hopfield neural network model for associative memories is presented that considers the case of a continuum of processing units. The state space corresponds to an infinite dimensional euclidean space. A dynamics is proposed that minimizes an energy functional that is a natural extension of the discrete case. The case in which the synaptic weight operator is defined through the autocorrelation rule (Hebb rule) with orthogonal memories is analyzed. We also consider the case of memories that are not orthogonal. Finally, we discuss the generalization of the non deterministic, finite temperature dynamics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009689025427
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  • 45
    Digitale Medien
    Digitale Medien
    Partial Compensation for Mismatched Uncertain Discrete Systems (2000)
    Springer
    Dynamics and control 10 (2000), S. 47-61 
    Details
    ISSN: 1573-8450
    Schlagwort(e): stability ; robust control ; Lyapunov approach ; discrete system
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract Control design of nonlinear discrete-time uncertain systems with (possibly fast) uncertain parameters is considered. We study the effect of only partially compensating the uncertainty. The optimal choice of a design parameter, which indicates the amount of compensation, is recommended.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008395928788
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  • 46
    Digitale Medien
    Digitale Medien
    Optimal Model Reduction with a Frequency Weighted Extension (2000)
    Springer
    Dynamics and control 10 (2000), S. 255-276 
    Details
    ISSN: 1573-8450
    Schlagwort(e): continuous-time systems ; frequency weighted model reduction ; gradient flow ; optimization ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract Inthis paper, a model reduction technique based on optimizationis presented. The objective function minimized is the impulseenergy of the overall system. An extension of the technique tothe frequency weighted case is also presented, where single-sidedor double-sided weightings can be incorporated in the reductionprocedure. The paper proposes an alternative to find an optimizationsolution by solving ordinary differential equations which aregradient flow associated with the objective function to be minimized.Two examples are presented to illustrate the effectiveness ofthe method.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008366812002
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  • 47
    Digitale Medien
    Digitale Medien
    The Equation of State of Lakes (2000)
    Springer
    Aquatic geochemistry 6 (2000), S. 1-17 
    Details
    ISSN: 1573-1421
    Schlagwort(e): lakes ; density ; compressibility ; expansibility ; conductivity ; stability ; pvt properties
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Geologie und Paläontologie
    Notizen: Abstract In recent years, a number of workers have studied the stability of deep lakes such as Lake Tanganyika, Lake Baikal and Lake Malawi. In this paper, the methods that can be used to determine the effect that the components of lakes have on the equation of state are examined. The PVT properties of Lakes have been determined by using apparent molal volume data for the major ionic components of the lake. The estimated PVT properties (densities, expansibility and compressibilities) of the lakes are found to be in good agreement with the PVT properties (P) of seawater diluted to the same salinity. This is similar to earlier work that showed that the PVT properties of rivers and estuarine waters could also be estimated from the properties of seawater. The measured densities of Lake Tanganyika were found to be in good agreement (± 2 × 10-6 g cm-3) with the values estimated from partial molal properties and the values of seawater at the same total salinity (ST = 0.568‰). The increase in the densities of Lake Tanganyika waters increased due to changes in the composition of the waters. The measured increase in the measured density (45 × 10-6 g cm-3) is in good agreement (46 × 10-6 g cm-3) with the values calculated for the increase in Na+, HCO3 -, Mg2+, Ca2+ and Si(OH)4. Methods are described that can be used to determine the conductivity salinity of lakes using the equations developed for seawater. By combining these relationships with apparent molal volume data, one can relate the PVT properties of the lake to those of seawater.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009626325650
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  • 48
    Digitale Medien
    Digitale Medien
    Surface Instability of Laminated Coatings upon Inelastic Deformation (2000)
    Springer
    Mechanics of composite materials 36 (2000), S. 475-480 
    Details
    ISSN: 1573-8922
    Schlagwort(e): stability ; three-dimensional theory ; tribotechnics ; elastoplastic deformations ; viscoelasticity ; surface ; tracking and dead loads ; laminated coating ; piecewise-homogeneous model ; active loading
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract The problem of surface instability of laminated coatings with inelastic properties is considered within the framework of a model of piecewise-homogeneous media on the basis of the three-dimensional linearized theory of stability. A general statement of the problem is formulated and the basic characteristic equations are derived. The solutions of particular problems are obtained for elastoplastic and viscoelastic models of solids.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006758600457
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  • 49
    Digitale Medien
    Digitale Medien
    Intraspecific Variation in the Vocalizations and Hand Pad Morphology of Southern Lesser Bush Babies (Galago moholi): A Comparison with G. senegalensis (2000)
    Springer
    International journal of primatology 21 (2000), S. 537-555 
    Details
    ISSN: 1573-8604
    Schlagwort(e): galago ; taxonomy ; vocalization ; morphology ; zoogeography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Previous studies have shown the taxonomic value of vocal repertoires and hand (volar) pad characteristics in the classification of cryptic nocturnal primates such as bush babies. However, no study included quantitative comparisons within the geographical range of any one species. We investigated levels of intraspecific variation in calls and hand pad characteristics of the southern lesser bush baby (Galago moholi), using the northern lesser bush baby (Galago senegalensis) for interspecific comparisons. Examination of calls recorded from different regions along a transect of 1500 km across southern Africa revealed low levels of intraspecific variation in Galago moholi, whereas comparisons with homologous call-types in G. senegalensis revealed them to be significantly different. Volar pad measurements across the ranges of both species also showed low levels of intraspecific variation and relatively high interspecific variation. These findings demonstrate that vocal and volar pad characteristics can be used as consistent measures of difference between species that look almost identical. These methods provide a practical means of distinguishing between cryptic species, whether in the field, in captivity, or, in the case of volar pads, of preserved specimens.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1005400205038
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  • 50
    Digitale Medien
    Digitale Medien
    Taxonomic Revision of Mouse Lemurs (Microcebus) in the Western Portions of Madagascar (2000)
    Springer
    International journal of primatology 21 (2000), S. 963-1019 
    Details
    ISSN: 1573-8604
    Schlagwort(e): mouse lemurs ; Microcebus ; taxonomy ; revision ; new species
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The genus Microcebus (mouse lemurs) are the smallest extant primates. Until recently, they were considered to comprise two different species: Microcebus murinus, confined largely to dry forests on the western portion of Madagascar, and M. rufus, occurring in humid forest formations of eastern Madagascar. Specimens and recent field observations document rufous individuals in the west. However, the current taxonomy is entangled due to a lack of comparative material to quantify intrapopulation and intraspecific morphological variation. On the basis of recently collected specimens of Microcebus from 12 localities in portions of western Madagascar, from Ankarana in the north to Beza Mahafaly in the south, we present a revision using external, cranial, and dental characters. We recognize seven species of Microcebus from western Madagascar. We name and describe 3 spp., resurrect a previously synonymized species, and amend diagnoses for Microcebus murinus (J. F. Miller, 1777), M. myoxinus Peters, 1852, and M. ravelobensis Zimmermann et al., 1998.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1005511129475
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  • 51
    Digitale Medien
    Digitale Medien
    Phylogenetic Relationships of Spider Monkeys (Ateles) Based on Mitochondrial DNA Variation (2000)
    Springer
    International journal of primatology 21 (2000), S. 381-420 
    Details
    ISSN: 1573-8604
    Schlagwort(e): phylogenetics ; taxonomy ; systematic ; Ateles ; Cebidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Our goal was to determine phylogenetic relationships among geographically and taxonomically distinct haplotypes of spider monkeys (Ateles) based on DNA sequence variation for the mitochondrial DNA control region and cytochrome c oxidase subunit II gene. We obtained samples from most previously recognized subspecies of Ateles, ranging from Central America throughout the Amazon Basin, to determine phylogenetic relationships among racially recognized groups. Comparison of DNA sequences using both parsimony analysis and genetic distance analysis produced phylogenetic relationships that were very similar for each genetic region. We analyzed the phylograms produced, along with associated bootstrap support, confidence probabilities, and genetic distances between taxonomic groups, to identify four monophyletic species of Ateles: Ateles paniscus, composed of haplotypes from the northeastern Amazon Basin; A. belzebuth in the southern Amazon Basin; A. hybridus, located primarily along the Magdalena River valley of Colombia; and A. geoffroyi, which includes two former species: A. geoffroyi and A. fusciceps. This arrangement is contradictory to long-held taxonomies of Ateles based on pelage variation and is similar to a recent analysis based on craniodental variation. Results of this investigation suggest patterns of gene flow, evolutionary relationships, and speciation patterns that are more plausible than previous pelage-based taxonomies, which required seemingly impossible patterns of gene flow. Conservation efforts aimed at protecting Ateles, one of the Neotropics most endangered genera, will also benefit from the findings presented in this paper.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1005435718241
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  • 52
    Digitale Medien
    Digitale Medien
    Use of Vocal Fingerprinting for Specific Discrimination of Gray (Microcebus murinus) and Rufous Mouse Lemurs (Microcebus rufus) (2000)
    Springer
    International journal of primatology 21 (2000), S. 837-852 
    Details
    ISSN: 1573-8604
    Schlagwort(e): vocalization ; sexual advertisement ; predator advertisement ; taxonomy ; evolution ; mouse lemur ; primate ; Madagascar
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Advertisement calls are often important noninvasive tools for discriminating cryptic species and for assessing specific diversity and speciation patterns in nature. We investigated the contribution of these calls to uncover specific diversity in nocturnal Malagasy lemurs. We compared sexual advertisement and predator advertisement calls of two mouse lemur species, western gray and eastern rufous mouse lemurs (Microcebus murinus and M. rufus, respectively) living in two contrasting habitats (dry deciduous vs. rain forest), and analyzed them statistically. Both species emitted several highly variable whistle calls in the context of predator-avoidance. Intrapopulation variation was high and overlapped interspecific variation. Sexual advertisement calls, given in the mating context, displayed a totally distinct, species-specific acoustic structure. Whereas gray mouse lemurs produced rapidly multifrequency modulated, long trill calls, rufous mouse lemurs gave slowly frequency-modulated short chirp calls. Our results suggest specific status for gray and rufous mouse lemurs and indicate the importance of predation and social needs in shaping vocal communication.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1005594625841
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  • 53
    Digitale Medien
    Digitale Medien
    On the Stability of Nonconservative Systems with Estimation of the Attraction Domain (2000)
    Springer
    Journal of dynamical and control systems 6 (2000), S. 503-510 
    Details
    ISSN: 1573-8698
    Schlagwort(e): nonconservative mechanical systems ; stability ; Lyapunov functions ; attraction domain
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract Mechanical systems subjected to dissipative, gyroscopic, conservative, and also nonconservative positional forces are considered. The question of the effect of dissipative, gyroscopic, and conservative forces on the motion stability of a mechanical systems is determined by classical Kelvin–Chetaev theorems [1]. The presence of nonconservative positional forces considerably complicates the situation and excludes direct application of these theorems. Applying Lyapunov's functions method the condition of asymptotic stability of a mechanical system under the action of all listed above forces is obtained. Moreover, the estimation of the attraction domain in phase space is found. The precession system which is used in the solution of some problems in the applied theory of the gyroscopic systems is also examined. The connection between the stability of origin and precession systems is detected. Theoretical results are applied to the stabilization problem of stationary motion of the balanced gimbal suspension gyro by means of external moments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009500527061
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  • 54
    Digitale Medien
    Digitale Medien
    Epicuticular wax morphology and the taxonomy ofRosa (sectionCaninae, subsectionRubiginosae) (2000)
    Springer
    Plant systematics and evolution 221 (2000), S. 107-112 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Rosaceae ; Rosa ; Caninae ; epicuticular waxes ; taxonomy ; hybridism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Classification within the genusRosa is problematic due to ± continuous variation of morphological characters. The dogroses, (Rosa, sectionCaninae) are classified only by their unique meiotic system not by directly visible characters. The intrasectional structure remains insufficient, as the characters (glands, hairs and prickles) are known to exhibit great morphological divergence affected by both genetic plasticity and environmental influences. Taxonomy of dogroses follows a highly artificial system which allows us to identify morphospecies, which are not necessarily evolutionary species. However, SEM-studies in theCaninae revealed that all taxa of the subsectionRubiginosae are characterised by a granule type of epicuticular waxes, whereas members from the other subsections (with three exceptions) form triangular rodlets. Comparison with specimens grown under the same conditions confirmed these findings on natural populations and additionally revealed that following artificial hybridism, offspring develop the maternal type of wax structure due to the matroclinal inheritance in this section.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01086384
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  • 55
    Digitale Medien
    Digitale Medien
    Software dependent phenetic relationships of non-nodulating African species ofAcacia (2000)
    Springer
    Plant systematics and evolution 220 (2000), S. 139-146 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Acacia ; classification ; Leguminosae ; morphology ; phenetics ; RAPD ; software ; taxonomy ; UPGMA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The phenetic analysis of non-nodulatingAcacia species by Harrier et al. (1997) was repeated to illustrate how different computer programs may generate alternative UPGMA trees for the very same data, even in the absence of data input order effects (ties). For example, all Harrier et al.'s UPGMA dendrograms produced by software from the Scottish Agricultural Statistics Service differed from those obtained by the packages NTSYS and MVSP87. Particularly, the positions ofA. albida, A. rovumae, andA. pentagona, as well as the relationships betweenDiacanthae andTriacanthae were affected by this phenomenon. Hence, whenever clustering techniques are used, care should be taken to consider possible software-dependent caveats and artefacts. Nevertheless, all programs provided clusterings that largely coincided with the subgeneric and sectional groupings proposed by Vassal (1972) although the positions of some species varied depending on whether morphological or molecular data were considered (e.g.A. albida andA. rovumae).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00985042
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  • 56
    Digitale Medien
    Digitale Medien
    Secretory cavities and pellucid dots in leaflets ofLonchocarpus (Leguminosae, Papilionoideae, Millettieae) (2000)
    Springer
    Plant systematics and evolution 221 (2000), S. 61-68 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Leguminosae ; Papilionoideae ; Lonchocarpus ; leaflets ; secretory cavities ; false secretory cavities ; pellucid dots ; glands ; anatomy ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The occurrence of leaflet secretory cavities in 23 Brazilian species ofLonchocarpus was surveyed anatomically and compared with data from external morphology (presence of pellucid dots) to evaluate their taxonomic significance. This study revealed three cases: presence of secretory cavities associated with pellucid dots, pellucid dots corresponding to false secretory cavities, and absence of pellucid dots and secretory cavities. These results indicate that in this genus the “glandular pellucid dots” cited in morphological descriptions do not always correspond to secretory cavities, and that their nature must always be confirmed by histological sections. Secretory cavities have systematic significance at subgeneric taxonomic level for the genusLonchocarpus.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01086380
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  • 57
    Digitale Medien
    Digitale Medien
    New chromosome counts inStreptocarpus (Gesneriaceae) from Madagascar and the Comoro Islands and their taxonomic significance (2000)
    Springer
    Plant systematics and evolution 224 (2000), S. 173-182 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Gesneriaceae ; Streptocarpus ; Chromosome numbers ; growth patterns ; taxonomy ; Africa ; Comoro Islands ; Madagascar
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This study records the chromosome numbers of 10 species ofStreptocarpus; nine of the counts are new. With the exception ofS. buchananii of mainland Africa, all the results are for plants endemic to Madagascar and the Comoro Islands. While there is a strong correlation between basic number and growth form in the two subgenera of the genus on the African mainland (x = 15 among caulescent species in subgenusStreptocarpella; x = 16 among acaulescent species in subgenusStreptocarpus), the situation appears more complex among Madagascan and Comoro Island species. One notable example of deviation from this correlation is shown byS. papangae, a shrubby caulescent species, with 2n = 32 (x = 16). Polyploidy in the genus appears to be absent on mainland Africa, but is present in Madagascar and the Comoro Islands, ranging from tetraploidy to octoploidy. Evolutionary implications of the cytological observations are considered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00986341
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  • 58
    Digitale Medien
    Digitale Medien
    Inter- and intraspecific genetic variation inHippophae (Elaeagnaceae) investigated by RAPD markers (2000)
    Springer
    Plant systematics and evolution 225 (2000), S. 85-101 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Elaeagnaceae ; Hippophae ; sea buckthorn ; Systematics ; taxonomy ; genetic variation ; RAPD
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Genetic diversity has been investigated by the application of molecular markers in, for the first time, all the taxa recognised in recent treatises of the genusHippophae. RAPD (random amplified polymorphic DNA) analyses were conducted with 9 decamer primers, which together yielded 219 polymorphic markers. We found 16 fixed RAPD markers, i.e. markers that either occurred in all plants of a population or were absent from all plants. Several of these markers were useful for analysis of interspecific relationships, whereas others can be considered as taxon-specific markers. Clustering of taxa and populations in our neighbour-joining based dendrogram was in good agreement with some recently suggested taxonomic treatises ofHippophae. Amount and distribution of genetic variability varied considerably between species. Partitioning of molecular variance withinH. rhamnoides supported earlier findings that a considerable part of the total variance resides among subspecies (59.6%) Within-population variability also differed considerably. Percentage polymorphic RAPD loci and Lynch and Milligan within-population gene diversity estimates showed relatively high values for some species close to the geographic centre of origin in Central Asia, e.g.H. tibetana and the putatively hybridogenousH. goniocarpa. Spatial autocorrelation analyses performed on 12 populations ofH. rhamnoides revealed positive autocorrelation of allele frequencies when geographic distances ranged from 0 to 700 km, and no or negative autocorrelation at higher distances. At distances between 700 and 1900 km, we observed deviations from the expected values with strongly negative autocorrelation of allele frequencies. A corresponding relationship between geographic and genetic distances could not be found when the analysis instead was based on one population from each of 8 species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00985460
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  • 59
    Digitale Medien
    Digitale Medien
    Recurrent selection in oat for adaptation to diverse environments (2000)
    Springer
    Euphytica 113 (2000), S. 195-205 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Avena ; genetic correlation ; genotype-environmentinteraction ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In order to test if selection can improve a population's adaptation to diverse environments simultaneously, three cycles of recurrent selection based on grain yield in Iowa, Idaho, and Norway were practiced in an oat (Avena sativaL.) population developed from North American, Scandinavian, and wild species (A. sterilis L.) germplasm sources. Specific objectives were to determine if selection: increased mean yields across environments and within all environments; changed the genetic correlation of yields in different environments; and changed genetic variation for yield within the population. We evaluated 100 to 210 randomly-chosen families from each cycle of selection at three Iowa locations, in Idaho, and in Norway for two years. Grain yield within each location and mean yields across locations increased significantly over cycles of selection. Mean yields across locations expressed as a percent of the original population mean increased at a rate of 2.6% per year. Several families from the third cycle population exhibited both high mean yields across locations and consistently high yields within all locations. Average genetic correlations of yield in different environments were higher in the second cycle than in the original population. A trend of reduced genetic variation and heritability was observed in Iowa only. These results suggest that we successfully improved mean population yield both within and across locations, and yield stability across environments, and in developing families with outstanding adaptation to diverse environments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003933421378
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  • 60
    Digitale Medien
    Digitale Medien
    Bdelloid rotifers from Korea (2000)
    Springer
    Hydrobiologia 439 (2000), S. 91-101 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Rotifera ; Bdelloidea ; Korea ; taxonomy ; biogeography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Twenty-five samples from 18 terrestrial and/or freshwater habitats in the eastern part of Korea yielded 38 new records of bdelloid rotifers, 22 of which are new to the Asian fauna. Among these Korean new records, Dissotrocha aculeata reversa Berzins and Habrotrocha plana Milne were recorded outside their type localities for the first time, and Macrotrachela bullata (Murray) was reported only from two countries after its description. Bradyscela granulosa de Koning, Habrotrocha gracilis gracilis Montet, Macrotrachela latior Donner, Philodina duplicalcar (de Koning) and P. rugosa coriacea Bryce are recorded outside Europe for the first time. The taxonomy and distribution of these rare species are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004181414535
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  • 61
    Digitale Medien
    Digitale Medien
    Interpopulation differentiation within C. kolensis and C. strenuus strenuus (Crustacea: Copepoda): evidence from cytogenetic methods (2000)
    Springer
    Hydrobiologia 417 (2000), S. 37-42 
    Details
    ISSN: 1573-5117
    Schlagwort(e): taxonomy ; cytogenetic methods ; Cyclops kolensis ; Cyclops strenuus strenuus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Comparisons of behavior of chromosomes and characteristics of eliminated chromatin during anaphase of chromatin diminution divisions were made of Russian and German populations of Cyclops kolensis and Cyclops strenuus strenuus. Differences in cytogenetic features included timing and amount of eliminated chromatin. Differences were also marked in duration of chromatin diminution, as well as timing and location of eliminated DNA between Russian and German populations of C. strenuus strenuus. In contrast to the German population of C. strenuus, the Russian population of C. strenuus strenuus did not exhibit gonomery.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003819809155
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  • 62
    Digitale Medien
    Digitale Medien
    Key to the identification of the genera of bdelloid rotifers (2000)
    Springer
    Hydrobiologia 418 (2000), S. 73-80 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Rotifera ; Bdelloidea ; pictorial key ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We propose a simple, user-friendly key joined to a pictorial key to the bdelloid genera, in the attempt to make bdelloid identification more accessible to non-bdelloid-specialists. The key is mostly based on illustrations rather than on descriptions, and is accompanied by an introduction of the main features readily observable in active bdelloids.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003840216827
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  • 63
    Digitale Medien
    Digitale Medien
    The morphology of the upper lip of Cypridoidea ostracods: taxonomic and phylogenetic significance (2000)
    Springer
    Hydrobiologia 418 (2000), S. 169-184 
    Details
    ISSN: 1573-5117
    Schlagwort(e): ostracods ; upper lip ; taxonomy ; phylogeny
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This paper represents the first study of the morphology of the upper lip (labrum) and hypostome of ostracods using scanning electron microscopy (S.E.M.). There is considerable variation in the upper lip morphology of the 23 species of Cypridoidea (Podocopina) ostracods used in this study. The detail of the upper lip morphology of each species is very distinctive, so that species determination can be made on this feature alone, but it is not useful in diagnosing genera or subfamilies. The hypostome is not readily studied due to the large amounts of dense pseudochaetae (small, setae-like projections) protruding from it and hence is considered not to be a useful taxonomic feature. Several features of the upper lip and mouth region are documented for the first time. Comparisons of the general morphology of the upper lips of Recent ostracods with the upper lip of the fossil ostracod Pattersoncypris micropapillosa Bate, 1972, indicate that there has been very conservative evolution in these features since the Cretaceous.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003934528762
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  • 64
    Digitale Medien
    Digitale Medien
    Ryocalanus spinifrons, a new species of Ryocalanidae (Copepoda: Calanoida), from the southwestern part of Sagami Bay, Japan (2000)
    Springer
    Hydrobiologia 432 (2000), S. 127-131 
    Details
    ISSN: 1573-5117
    Schlagwort(e): new species ; Ryocalanoid copepod ; taxonomy ; benthopelagic ; Sagami Bay
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A new Ryocalanoid copepod, Ryocalanus spinifrons, collected by the MTD net system at a depth of 1400 m from the southwestern part of Sagami Bay, Japan, is described. The new species is morphologically very close to R. infelix Tanaka, 1956 (female unknown) from the Izu region of Sagami Bay. It is distinguished from other species by the presence of 12 long spinules on the ventral inner side of the fifth pedigerous somite, nine setae on the coxal epipodite of the maxillule and nine large robust spinules on the coxal segment of the fourth leg. The row of five robust spines on the paragnath distinguishes R. spinifrons.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004090724831
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  • 65
    Digitale Medien
    Digitale Medien
    Taxonomic analysis of species characters for copepodid instars 4 and 5 of the subfamily Eucyclopinae of European Russia (2000)
    Springer
    Hydrobiologia 417 (2000), S. 57-79 
    Details
    ISSN: 1573-5117
    Schlagwort(e): copepodid instars ; Eucyclopinae ; taxonomy ; morphological characters
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Morphological characters useful for taxonomic identification of older copepodid instars of the subfamily Eucyclopinae were studied among 14 species of Eucyclops, Macrocyclops, Ectocyclops, Paracyclops and Tropocyclops known from European Russia. For taxonomic analysis, the following elements of copepodid morphology were chosen: armament and proportion of furcal rami; morphology of swimming legs and reduced 5th and 6th legs; antennule segmentation; and relative body length of copepodid instars in comparison with the female length. Changes in morphology of major copepodid instars of the subfamily Eucyclopinae during ontogenetic development are traced and noticeable differences among five genera and 14 species are described. These differences among major copepodid stages may be important for both taxonomic and ecological analysis. For taxonomy, they provide information on development of sexes and species during maturation. For ecology they allow identification of the specimens at 4–5 copepodid instars in diapause. A key to major copepodid instars of the species from the subfamily Eucyclopinae which are known from limnetic habitats of the European part of Russia is presented.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003878616907
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  • 66
    Digitale Medien
    Digitale Medien
    Components of morphological variation in Baikalian endemial cyclopid Acanthocyclops signifer complex from different localities (2000)
    Springer
    Hydrobiologia 417 (2000), S. 25-35 
    Details
    ISSN: 1573-5117
    Schlagwort(e): morphological variation ; fluctuating asymmetry ; taxonomy ; Copepoda ; Cyclopidae ; Acanthocyclops signifer ; Lake Baikal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Use of traditional methods for morphological studies only permits the analysis of a small part of the information embodied in morphological structures. Besides comparing populations using the mean values of characters which allows one to estimate their morphological similarity, analysis of variation among individuals within a population can be informative. Variation among individuals consists of factorial and stochastic components. The factorial component is an upper estimate of genetic heterogeneity and thus permits one to evaluate the population's adaptability. The stochastic component (estimated by fluctuating asymmetry, i.e. random deviations from perfect bilateral symmetry), being a measure of developmental stability, is an indicator of a population's fitness. Assessment of measurement error is necessary for assessment of the true value of the stochastic component and for selection of the most informative characters. Such analysis allows one to extract additional information from morphological data in comparison with methods traditionally used on copepods. This approach was applied to an analysis of morphological variation in the study of the Baikalian endemic cyclopoid Acanthocyclops signifer (Mazepova) from three different isolated localities. Characters typically used in studies of taxonomy of this group are considered here. Measurement error was rather high (more than 50% of the stochastic component), which can be explained by technical difficulties of measuring the characters. All populations differ in the mean values of the characters. This shows the taxonomic heterogeneity of this group and reveals the necessity of its taxonomic revision. Populations also differ in the level of stochastic and factorial components of the total variance. The data are interpreted from the point of view of taxonomy and the possible evolution of the group.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003866215089
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  • 67
    Digitale Medien
    Digitale Medien
    Nitocrellopsis texana n. sp. from central TX (U.S.A.) and N. ahaggarensis n. sp. from the central Algerian Sahara (Copepoda, Harpacticoida) (2000)
    Springer
    Hydrobiologia 418 (2000), S. 81-97 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Harpacticoida ; new species ; redescription ; taxonomy ; troglobitics ; trans-Atlantic distribution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Nitocrellopsis texana n. sp. found in samples collected by SCUBA divers in Honey Creek Cave (Texas, U.S.A.) is described. This species is the first representative of this stygobitic taxon from a Northern American locality. The original description of N. ioneli (Dumont & Decraemer, 1975) is amended and the closely related N. ahaggarensis n. sp. is described from a well near Tamanghasset in the Ahaggar mountains in Algeria. The monophyly of Nitocrellopsis is discussed and its present day distribution is analyzed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003892200897
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  • 68
    Digitale Medien
    Digitale Medien
    The dinoflagellate genus Prorocentrum along the coasts of the Mexican Pacific (2000)
    Springer
    Hydrobiologia 418 (2000), S. 111-121 
    Details
    ISSN: 1573-5117
    Schlagwort(e): dinoflagellates ; Prorocentrum ; morphology ; taxonomy ; Mexican Pacific ; red tides
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We surveyed the dinoflagellate genus Prorocentrum Ehrenberg in Mexican Pacific waters, where it is rather common and sometimes causes red tides in coastal areas or shrimp farms. Material collected from Baja California and the Gulf of California was analyzed. Thirteen species were identified, all of them planktonic (although P. mexicanum is also epiphytic). All species are described by light microscopy, and most are also described by scanning electron microscopy; comments on morphology, taxonomy and distribution are made. Red tides were caused by P. dentatum, P. minimum and P. triestinum. Prorocentrum mexicanum and P. minimum were suspected of being toxic. Four species, previously reported in the Gulf of California, were not found. A total of 18 species, including the new records P. dactylum and P. lebourae have been to date reported from the Mexican Pacific.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003806719515
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  • 69
    Digitale Medien
    Digitale Medien
    Eucyclops dumonti sp.nov. from Central Mongolia (2000)
    Springer
    Hydrobiologia 441 (2000), S. 63-71 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Mongolia ; Eucyclops dumonti ; taxonomy ; zooplankton ; spring fauna
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Eucyclops dumonti sp.nov. is described from a shallow spring-fed lake in Central Mongolia. Data on its morphological variability are given, a comparison with the type population of Eucyclops serrulatus (Fischer, 1853) from St. Petersburg area is made, and its position relative to some closely related congeners is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1017592005551
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  • 70
    Digitale Medien
    Digitale Medien
    Redescription of Diaphanosoma dubium Manuilova, 1964 (Branchiopoda: Ctenopoda: Sididae), and description of a new, related species (2000)
    Springer
    Hydrobiologia 441 (2000), S. 73-92 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Diaphanosoma dubium ; D. pseudodubium sp.nov. ; morphology ; taxonomy ; geographical distribution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The poorly known D. dubium Manuilova is redescribed on extensive material from more than 80 populations from the Russian Far East, Central Asia, Mongolia, China, Japan, Vietnam, the Philippines, Thailand, Malaysia, Bangladesh, India and Sri Lanka. Its morphological variability and geographical distribution are analysed and supplemented by notes on biology. The conspecificity of morphologically different distant populations is discussed. In the northern part of its range, D. dubium was long confused with D. brachyurum or D. leuchtenbergianum, and in the south with D. modigliani. It seems that the recent appearance of D. dubium in fish ponds of Uzbekistan and Kazakhstan was an introduction, together with Far Eastern fish. D. pseudodubium sp.nov., close to but markedly different, is described from two lakes in the lower Amur river system. D. dubium, D. pseudodubium, D. tropicum and D. modigliani s. str. form a group of related species, widely distributed in Eastern and Southern Asia.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1017574921558
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  • 71
    Digitale Medien
    Digitale Medien
    Molecular genetic analyses of species boundaries in the sea (2000)
    Springer
    Hydrobiologia 420 (2000), S. 73-90 
    Details
    ISSN: 1573-5117
    Schlagwort(e): sibling species ; taxonomy ; DNA ; electrophoresis ; allozymes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The tools of molecular genetics have enormous potential for clarifying the nature and age of species boundaries in marine organisms. Below I summarize the genetic implications of various species concepts, and review the results of recent molecular genetic analyses of species boundaries in marine microbes, plants, invertebrates and vertebrates. Excessive lumping, rather than excessive splitting, characterizes the current systematic situation in many groups. Morphologically similar species are often quite distinct genetically, suggesting that conservative systematic traditions or morphological stasis may be involved. Some reproductively isolated taxa exhibit only small levels of genetic differentiation, however. In these cases, large population sizes, slow rates of molecular evolution, and relatively recent origins may contribute to the difficulty in finding fixed genetic markers associated with barriers to gene exchange. The extent to which hybridization blurs species boundaries of marine organisms remains a subject of real disagreement in some groups (e.g. corals). The ages of recently diverged species are largely unknown; many appear to be older than 3 million years, but snails and fishes provide several examples of more recent divergences. Increasingly sophisticated genetic analyses make it easier to distinguish allopatric taxa, but criteria for recognition at the species level are highly inconsistent across studies. Future molecular genetic analyses should help to resolve many of these issues, particularly if coupled with other biological and paleontological approaches.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003933603879
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  • 72
    Digitale Medien
    Digitale Medien
    A new Ceratium species (Dinophyceae) from Lake Doïrani, Macedonia, Greece (2000)
    Springer
    Hydrobiologia 424 (2000), S. 101-108 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Ceratium ; freshwater ; ecology ; morphology ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A new taxon of Ceratium is described from Lake Doïrani, Greece. It is proposed as a new species and named Ceratium monoceras. It differs morphologically from known species of Ceratium by having only one horn, the apical horn. Accordingly, the vegetative cells form cysts that have only one spine. Details of its ecology and occurence are given.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003957129071
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  • 73
    Digitale Medien
    Digitale Medien
    Nematodes from the Strait of Magellan and the Beagle Channel (Chile): the genera Cervonema and Laimella (Comesomatidae: Nematoda) (2000)
    Springer
    Hydrobiologia 427 (2000), S. 27-49 
    Details
    ISSN: 1573-5117
    Schlagwort(e): taxonomy ; marine nematodes ; Cervonema ; Laimella ; the Strait of Magellan ; Chile
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Five species of Cervonema and four species of Laimella are described from the Strait of Magellan and the Beagle Channel, Chile, six species of which are new to science. Cervonema chilensisn. sp. and Cervonema hermanin. sp. are separated from other known species of Cervonema by a short cervical region (less than one head diameter from the front end to the anterior border of the amphids). Cervonema chilensisn. sp. is characterised by a tail length of 5 anal diameters with posterior half filiform; Cervonema hermani n. sp. is characterised by a tail length of 6–9 anal diameter and posterior part (75%) cylindrical. Cervonema shiaen. sp. is characterised by the cephalic seta 4 μm long, amphids 9–10 μm in diameter; spicules 16 μm long and 0.8–0.9 abd; tail 4.7–5.4 anal diameter and 50% posterior part filiform; 4–5 minute precloacal supplements. Laimella subterminatan. sp. is characterised by the subterminal position of the buccal cavity which separates it from the other species of the genus. Laimella annaen. sp. is characterised by the head diameter 9–11 μm, cephalic setae and external labial setae 9 + 5 μm long, respectively, amphids 7 μm in diameter; spicules 28–30 μm long; tail 14–17 anal diameter and posterior part (75%) filiform; 5 precloacal supplements. Laimella sandraen. sp. is very close to Laimella annaen.sp. in having similar cephalic sensilla, amphids and spicules. Laimella sandraen. sp., however, can be separated from L.annaen. sp. by the shape of head and the structure of sperm cells, the total body length and the cylindrical part of tail. Cervonema papillatum Jensen, 1988, C. tenuicauda (Stekhoven, 1950) and L. longicauda Cobb, 1920 are found in this area as well. The key of all known species of Cervonemaand Laimellais presented.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003943021901
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  • 74
    Digitale Medien
    Digitale Medien
    Description of a new Nipergasilus species (Family: Ergasilidae) from the gills of grey mullet (2000)
    Springer
    Hydrobiologia 428 (2000), S. 61-66 
    Details
    ISSN: 1573-5117
    Schlagwort(e): parasitic Copepoda ; taxonomy ; new species ; grey mullet
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A new Nipergasilus species is described from the gills of the grey mullet Valamugil cunnesius from several localities in India and Pakistan. The new species is closely related to Nipergasilus bora (Yamaguti, 1939) which is also recorded here on three species of grey mullet. The genus Nipergasilus is redefined in order to accommodate the second species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003931713959
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  • 75
    Digitale Medien
    Digitale Medien
    New species of Rhynchelmis (Clitellata, Lumbriculidae), with observations on the Nearctic species (2000)
    Springer
    Hydrobiologia 428 (2000), S. 1-59 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Clitellata ; Oligochaeta ; Lumbriculidae ; Rhynchelmis ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The Nearctic species of Rhynchelmis (Lumbriculidae) are distinguished from the Palearctic group Rhynchelmis s. str. by longitudinal muscle bands that do not curl inwards. Six new species from western North America support the existence of two major groupings within the Nearctic fauna. Species in Group 1 are distinguished from other Rhynchelmis by large penial bulbs and multiple spermathecal diverticula. Within Group 1, Rhynchelmis yakimorum n. sp., Rhynchelmis monsserratus n. sp., Rhynchelmis gustafsoni n. sp. and Rhynchelmis utahensis n. sp. differ from the related Rhynchelmis (=Sutroa) rostrata in having short penes and spermathecae with 2 short, lobed diverticula. R. monsserratus is distinguished by a single, median spermatheca, R. gustafsoni has closely appressed, median spermathecae and atria, and R. utahensis differs in structural details of spermathecae and male pores. Rhynchelmis gilensis n. sp. has a single, median spermatheca with unbranched diverticula and distinctive nephridia. Redescription of material from the type localities of both Sutroa alpestris and R. rostrata supports their combination. Group 2, corresponding in part to Rhynchelmoides, is distinguished from Group 1 mostly by characters that are inconsistent or appear plesiomorphic. Within Group 2, Rhynchelmis saxosa n. sp. closely resembles Rhynchelmis alaskana, except for the absence of lateral blood vessels in posterior segments and distribution of prostates. Rhynchelmis elrodi and Rhynchelmis glandula consistently differ in presence of ventral glands and have different distributions, so their supposed synonymy is rejected.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003919312142
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  • 76
    Digitale Medien
    Digitale Medien
    New species of Metepsilonema (Nemata, Epsilonematidae) from the Channel and the Mediterranean Sea with a polytomous key for the identification of species of the genus (2000)
    Springer
    Hydrobiologia 429 (2000), S. 25-47 
    Details
    ISSN: 1573-5117
    Schlagwort(e): marine nematodes ; Epsilonematidae ; Metepsilonema ; taxonomy ; key to species
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Four new species of Metepsilonema are described from sublittoral stations from the Channel and are mainly characterized: M. volutum sp.nov. by the large body size for the genus up to 460 μm, 118–121 well overlapping annuli and wide multispiral amphids; M. amphidoxum sp.nov. by 127–133 shortly overlapping annuli and sexual dimorphism in amphid size; M. comptum sp.nov. by 133–140 non-overlapping annuli, anteriormost annuli provided with a wide lumen and borders ornamented with ridges and M. corrugatum sp.nov. by 108–111 overlapping annuli provided with ridges). Additional information is provided for M. callosum together with a discussion on intraspecific variability. A new species of Metepsilonema spec. based on females only, is described but remain unnamed. M. comptum sp.nov. and M. corrugatum sp.nov. are also occurring in the Mediterranean Sea. A polytomous key to species level is presented.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003975425673
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  • 77
    Digitale Medien
    Digitale Medien
    The freeliving nematode genus Parodontophora Timm 1963 (Nematoda: Axonolaimidae) is not exclusively marine: Parodontophora limnophila sp. nov. from freshwater in China (2000)
    Springer
    Hydrobiologia 431 (2000), S. 205-210 
    Details
    ISSN: 1573-5117
    Schlagwort(e): China ; freshwater ; Nematoda ; new species ; Parodontophora ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Parodontophora limnophila sp. nov. is described from Poyang Lake, the largest freshwater lake of China. It is characterized by having an amphid with its posterior end close to the base of the stoma, relatively short cephalic setae, opisthocephalic setae arranged as two subdorsal groups of three longitudinally arranged setae and two single subventral setae, excretory pore at the level of the anterior part of the stoma and renette gland 34–47% of the oesophageal length. To date, the new species is the only Parodontophora species found in freshwater habitats.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004052531906
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  • 78
    Digitale Medien
    Digitale Medien
    Morariopsis dumonti n.sp. (Crustacea: Copepoda: Harpacticoida) – a new species from an unsaturated karstic zone in Slovenia (2000)
    Springer
    Hydrobiologia 436 (2000), S. 73-80 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Harpacticoida ; ground water ; interstitial ; taxonomy ; Slovenia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The genus Morariopsishas a disjunct distribution. It has been found in south-eastern Europe and in the Baikal region in Russia. In Europe two species are known, both from the Dinaric region. They have been found in three caves only, but always in puddles filled with percolating water. This indicates that they inhabit an unsaturated karstic environment. A third species, Morariopsis dumontin.sp has now been found, in the same type of habitat, on several dates, in a small cave in central Slovenia. Males were recorded for the first time in this genus. The new species is related to Morariospsis kieferiPetkovski, 1959 from Dalmatia. The main differences are in the ornamentation of the furca and of the abdominal segments. P5 and particularly endopodite of P4 in males suggest a close relation between Morariaand Morariopsis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1026585820968
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  • 79
    Digitale Medien
    Digitale Medien
    Parastenocaris andreji n. sp. (Crustacea; Copepoda) – the first record of the genus in Slovenia (SE Europe) (2000)
    Springer
    Hydrobiologia 437 (2000), S. 235-239 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Harpacticoida ; ground water ; interstitial ; taxonomy ; Slovenia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Parastenocaris andreji n. sp. was found in ground water in a northwestern part of Slovenia (southern part of Central Europe). Two adult females of the new species were filtered out of 20 000 l of water during examination of an aquifer for water supply. The bore well was 10 m deep. The aquifer is fed by rainwater and probably only occasionally from a nearby alpine river Sava. The new species differs markedly from other known species of the genus by shape and armature of furcal rami, very long and slim maxillae and some characters on endopodites P2–P5. The closest related species are probably Parastenocaris nolliKiefer, 1938 with subspecies P. nolli alpinaKiefer, 1960, P. gertrudae Kiefer, 1968 and P. austriacaKiefer, 1976.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1026513917821
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  • 80
    Digitale Medien
    Digitale Medien
    Determination of primary structure of amberjack myosin heavy chain and its relationship with structural stability of various fish myosin rods (2000)
    Springer
    Fish physiology and biochemistry 23 (2000), S. 283-294 
    Details
    ISSN: 1573-5168
    Schlagwort(e): amberjack ; myosin heavy chain ; cDNA ; α-helix ; coiled coils ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The structural stability of fish myosin depends upon species and temperatures of water in which fish live. Primary, secondary, and quaternary structures of myosin heavy chain (MyHC) from three species of fish living at different temperature ranges have been compared with those of rabbit MyHC in order to investigate the differences in stability. Primary structure of MyHC, although being accessible for warm-water and cold-water fish (carp and walleye pollack), was not available in previous for tropical-water fish literature; so in this study primary structure of MyHC of the tropical-water fish amberjack has been determined by cloning and sequencing its cDNA. The MyHC has 1938 amino acid residues (AA), which are almost as much as as those of carp and walleye pollack. The amberjack MyHC is 91–95% homologous with other fish and rabbit MyHCs. There is a discernible difference between animal species with stable myosin rod (amberjack, carp, and rabbit) and walleye pollack with unstable rod. Stable rod species have a high probability of forming coiled-coil around the COOH-terminal end of the rod, while the pollack has a low coiled-coil formation probability. In addition, the average scores of the coiled-coil for myosin rod were rabbit (1.738) 〉 amberjack (1.691) 〉 carp (1.680) 〉 walleye pollack (1.674) which correlated exactly with the observed stability. The results suggest that coiled-coil forming ability, particularly around the COOH-terminal end, directs structural stability of fish myosin rod.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1011176105285
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  • 81
    Digitale Medien
    Digitale Medien
    Thermotolerant fungi erroneously reported in applied research work as possessing thermophilic attributes (2000)
    Springer
    World journal of microbiology and biotechnology 16 (2000), S. 869-880 
    Details
    ISSN: 1573-0972
    Schlagwort(e): Biotechnology ; ecology ; fungi ; nomenclature ; synopsis ; taxonomy ; thermophilic ; thermotolerant
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract In applied research work dealing with heat-tolerant fungi, currently classified into two groups: namely thermotolerants and thermophiles, information on levels of thermotolerance is generally scant. Cited binomials are often referred to as representatives of thermophilic taxa. The present contribution attempts to specify proper heat-tolerance levels of species cited in biotechnological papers of academic and applied research types published in the last four decades. This assessment integrates relevant available information concerning well defined thermotolerant taxa. Distinction between both groups of heat-tolerant fungi is a mean to optimize investigations of temperature-dependent physiological processes. The nomenclatural status of the binomials retrieved was also re-appraised following the International Code of Botanical Nomenclature. Articles of the code govern the legal validity of fungal names. The goal is to deter `ghost names' that have no status of any kind. Their use in the literature is not only a source of confusion but also hinders the preparation of sound reviews and reference documents. The intention was also to detect names which do not fulfill all criteria for a valid legal publication. Their status could then be validated if the taxonomic position of the fungus justifies this procedure. The taxonomic status of these thermotolerants was also re-examined following present-day knowledge of their respective genera. Integration of warranted taxonomic decisions in the literature of applied research is crucial. These decisions consider the status of a fungus as a valid species (proposed synonymies) or the nature of its generic affinities (name change). Strict application of these decisions severly reduces levels of heterogeneity regarding names used for the same organism. It also clarifies its generic affinities with other thermotolerant fungi. The present note is not an exhaustive assessment on the nomenclatural and taxonomic positions of known thermotolerant fungi, an ecological group for which a global document remains to be produced. It only deals with those taxa most commonly cited in the literature examined. Over 130 fungi are here considered. The group manifests a diversity of taxonomic characters since it includes members of the following systematic groupings: Oomycetes, Zygomycetes, Ascomycetes, anamorphic fungi and Holobasidiomycetes. Few new taxonomic synonyms and invalid binomials are introduced in the present contribution. The former concern the following taxa: Gilmaniella thermophila, Mucor thermoaerospora, Sporotrichum lignicola and Zalerion thermophylii. Three binomials proved to have no taxonomic status of any sort: Acremonium cellulophilum, Nodulisporium microsporum and N. thermoroseum.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008979123304
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  • 82
    Digitale Medien
    Digitale Medien
    Young children's partitioning strategies (2000)
    Springer
    Educational studies in mathematics 43 (2000), S. 191-221 
    Details
    ISSN: 1573-0816
    Schlagwort(e): analog objects ; children's informal knowledge ; conceptual mapping ; fair shares ; partitive quotient fraction construct ; partitioning tasks ; partitioning strategies ; quantification ; taxonomy ; teaching interventions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract Taxonomies for classifying children's partitioning strategies have generally focused on the contexts in which the strategies occur and whether the strategies generate fair shares. Therefore, the overall aim of this study was to increase our knowledge about young children's partitioning strategies by setting out not only to identify new partitioning strategies but also to develop a taxonomy for classifying young children's partitioning strategies in terms of their ability to facilitate the abstraction of the partitive quotient fraction construct from the concrete activity of partitioning objects and/or sets of objects. Clinical interviews were conducted with twelve purposely-selected Year Three students. Each student was presented with a unique set of realistic partitioning tasks. The paper concludes with a taxonomy for: (i) qualitatively evaluating a child's progress towards the abstraction of the partitive quotient fraction construct, and (ii) planning and implementing teaching interventions commensurate with the child's level of progress towards the abstraction of the partitive quotient fraction construct. This taxonomy provides researchers and teachers with means of better utilising children's informal partitioning strategies as the foundation upon which to further develop their understandings of the partitive quotient fraction construct.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1017513716026
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  • 83
    Digitale Medien
    Digitale Medien
    Numerical Investigation of a Stability Theorem Arising from the 2-Dimensional Analysis of an Iterative Optimal Control Algorithm (2000)
    Springer
    Multidimensional systems and signal processing 11 (2000), S. 109-124 
    Details
    ISSN: 1573-0824
    Schlagwort(e): 2-D linear systems ; optimal control ; stability ; unit memory linear repetitive processes ; numerical methods
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract Because many optimal control problems require solution using iterative procedures they fall naturally in the realm of 2-D systems where the two dimensions are response time horizon and iteration index, respectively. The paper uses this observation to employ 2-D systems theory, in the form of unit memory repetitive process techniques, to analyse local stability and convergence behaviour of a continuous optimal control algorithm based on dynamic system optimisation and parameter estimation. Existing work is extended to incorporate unmatched terminal constraints. Necessary and sufficient conditions for stability are obtained whose evaluation require the solution of a difficult eigenvalue problem. The paper shows how solutions can be achieved using numerical and graphical facilities of MATLAB.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008490731182
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  • 84
    Digitale Medien
    Digitale Medien
    The Jump Behavior and Stability Analysis for 2-D Singular Systems (2000)
    Springer
    Multidimensional systems and signal processing 11 (2000), S. 339-358 
    Details
    ISSN: 1573-0824
    Schlagwort(e): 2-D systems ; descriptor systems ; singular systems ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract In this paper, we discussthe jump behavior and stability problems for 2-D linear shift-invariantsingular systems under the standard boundary conditions. It isshown that once a boundary condition or the input is inadmissiblein the classical sense, a group of non-causal or backward jumpsof the system states will be incited. This interpretation releasesthe conventional admissibility constraints on the boundary conditionsand inputs. Based on this observation, a systematic stabilitytheory is developed for 2-D singular systems. The well-knownbasic stability theorem for the 1-D singular systems or 2-D regularsystems is thus extended to the 2-D singular case.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008429611994
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  • 85
    Digitale Medien
    Digitale Medien
    Pichia sporocuriosa sp. nov., a new yeast isolated from rambutan (2000)
    Springer
    Antonie van Leeuwenhoek 77 (2000), S. 37-42 
    Details
    ISSN: 1572-9699
    Schlagwort(e): new yeast species ; Pichia sporocuriosa ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A strain of a hitherto undescribed yeast species with a unique ascospore morphology was isolated from rambutan (Nephelium lappaceum). A description of the new species, Pichia sporocuriosa, is given.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1002095523955
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  • 86
    Digitale Medien
    Digitale Medien
    Phylogenetic analysis of Bacillus subtilis and related taxa based on partial gyrA gene sequences (2000)
    Springer
    Antonie van Leeuwenhoek 78 (2000), S. 123-127 
    Details
    ISSN: 1572-9699
    Schlagwort(e): Bacillus subtilis ; gyrA ; phylogeny ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Partial gyrA sequences were determined for twelve strains belonging to Bacillus amyloliquefaciens, B. atrophaeus, B. licheniformis, B. mojavensis,B. subtilis subsp. subtilis, B. subtilissubsp. spizizenii and B. vallismortis. The average nucleotide and translated amino acid similarities for the seven type strains were 83.7 and 95.1%, respectively, whereas the corresponding value for the 16S rRNA sequences was 99.1%. All of the type strains were sharply separated; the closest relationship was found between B. atrophaeus and B. mojavensis which shared a nucleotide similarity of 95.8%. Phylogenetic trees were inferred from gyrA nucleotide sequences using the neighbor-joining, Fitch–Margoliash and maximum parsimony algorithms. The test strains were divided into four groups, which generally reflected results previously reported in restriction digest and DNA-DNA hybridization studies. It is concluded from the comparative sequence analysis that the gyrA sequences provide a firm framework for the rapid and accurate classification and identification of Bacillus subtilis and related taxa.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1026555830014
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  • 87
    Digitale Medien
    Digitale Medien
    Re-examination of some species of the genus Geotrichum Link: Fr (2000)
    Springer
    Antonie van Leeuwenhoek 77 (2000), S. 71-81 
    Details
    ISSN: 1572-9699
    Schlagwort(e): DNA heterogeneity ; genome comparison ; Geotrichum ; taxonomy ; yeast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The nutritional physiology and the growth rate of thirty-four strains representing species of Geotrichum without known teleomorph states were examined. From twenty-seven strains the mol% G+C were calculated from the DNA melting curves. The first derivatives of the melting curves of seven strains, including the type strain of Geotrichum clavatum, demonstrated the presence of two peaks, 12% away from each other; the remaining strains showed only a single broad peak. DNA homology values among strains of the former group were high, indicating their conspecificity. The strains of the latter group could be subdivided into six DNA homology groups, four of which could be identified with recognized species and two may represent novel taxa. A combined key of Geotrichum and its teleomorph states Galactomyces and Dipodascus is presented.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1002030518989
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  • 88
    Digitale Medien
    Digitale Medien
    Species of the genus Psoroptes (Acari: Psoroptidae): A taxonomic consideration (2000)
    Springer
    Experimental and applied acarology 24 (2000), S. 213-225 
    Details
    ISSN: 1572-9702
    Schlagwort(e): Psoroptes ; taxonomy ; species differentiation ; phenotype ; genotype
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The biosystematic status of mite species belonging to the genus Psoroptes Gervais, 1841 is difficult to determine by phenotypic methods and has been subject to taxonomic revisions and ongoing debate. At present, the existence of five species, P. cuniculi (Delafond, 1859), P. ovis (Hering, 1838), P. equi (Hering, 1838), P. cervinus Ward, 1915 and P. natalensis Hirst, 1919, is generally accepted. This classification is based mainly on the host species, the localization of the mites on their hosts and morphological characters of male mites. However, a critical review of the literature indicates that the features used to discriminate between the five species are not unequivocal: (a) the localization of mite populations on host animals is not completely strict, (b) the lengths of the outer opisthosomal setae of male mites, which are the main morphological features used for species discrimination, overlap between the five postulated species, and (c) host specificity cannot be deduced from results of transfer experiments. Rather, conspecificity of the members of the genus Psoroptes has to be presumed which is supported by molecular genetic analyses. On these grounds and on rules of priority P. cervinus Ward, 1915, P. cuniculi (Delafond, 1859), P. natalensis Hirst, 1919 and P. ovis (Hering, 1838) are seen as synonyms of P. equi (Hering, 1838).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006443722815
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  • 89
    Digitale Medien
    Digitale Medien
    Emendation of the basidiomycetous yeast genus Kondoa and the description of Kondoa aeria sp. nov (2000)
    Springer
    Antonie van Leeuwenhoek 77 (2000), S. 293-302 
    Details
    ISSN: 1572-9699
    Schlagwort(e): Basidiomycetous yeasts ; Kondoa aeria sp. nov. ; ribosomal DNA sequencing ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The genus Kondoa Y. Yamada, Nakagawa & Banno was erected to accommodate a single taxon, K. malvinella (Fell & Hunter) Y. Yamada, Nakagawa & Banno, which was transferred from the teliospore-forming genus Rhodosporidium Banno based on pronounced differences in the 5S and 26S ribosomal RNA (rRNA) nucleotide sequences to R. toruloides Banno. In contrast with the original description, reinvestigation of K. malvinella revealed the formation of transversely septate (auricularioid) basidia that did not arise on teliospores, but formed directly on the dikaryotic mycelium. The four-celled basidia developed sterigmata on which forcibly discharged asymmetric basidiospores (ballistospores) were produced. Additionally, a new taxon emerged from the study of recent isolates, for which the name K. aeria sp. nov. is proposed. This new species produced two-celled auricularioid basidia on hyphae with incomplete clamp connections. Ballistospores arose on the basidia at the tip of sterigmata and, after ejection, germinated by budding. These observations led us to present an emended diagnosis for the genus Kondoa. Analysis of the sequence data from the D1/D2 region of the 26S rRNA gene showed a very close resemblance between K. aeria and K. malvinella in a cluster that also contained several Bensingtonia species. Taxa in this cluster share specific physiological traits and produce characteristic pinkish-cream to mauve colonies; in contrast, formation of ballistoconidia is only observed in the Bensingtonia species. Sequence data supported placement of K. malvinella and K. aeria in the `Agaricostilbum clade' of the Urediniomycetes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1002453628455
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  • 90
    Digitale Medien
    Digitale Medien
    An information retrieval system for VIR's herbarium, St. Petersburg, Russia, as a tool for cultivated plant research (2000)
    Springer
    Genetic resources and crop evolution 47 (2000), S. 147-152 
    Details
    ISSN: 1573-5109
    Schlagwort(e): cultivated plants ; databases ; herbarium ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The herbarium collection of the N.I. Vavilov Institute of Plant Industry (WIR) contains specimens of cultivated plants, their wild relatives and weedy plants and provides ample opportunities for research. It is a unique special herbarium collection and one of those rare collections having a card index (catalog). For the catalog to be functional, it should reflect the current changes in the taxa names. Only a computerized card file may meet this requirement. The creation of a database for VIR's herbarium was launched in 1995. VIR is carrying out a range of work necessary for providing a wider access to its herbarium and related information for the international scientific community.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008762024513
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  • 91
    Digitale Medien
    Digitale Medien
    Population diversity of the Vicia sativa agg. (Fabaceae) in the flora of the former USSR deduced from RAPD and seed protein analyses (2000)
    Springer
    Genetic resources and crop evolution 47 (2000), S. 171-183 
    Details
    ISSN: 1573-5109
    Schlagwort(e): evolution ; genetic resources ; RAPDs ; seed protein electrophoresis ; taxonomy ; Vicia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The genetic diversity of 58 wild and weedy populations representing taxa within the V. sativa aggregate from the former USSR, 4 cultivars of V. sativa, 2 accessions of V. cordata and 3 accessions of V. macrocarpa from Mediterranean countries were analysed using randomly amplified DNA fragments (RAPDs) and seed protein electrophoresis (SDS-PAGE). Interspecific variation between taxa in the V. sativa aggregate could readily be detected using both techniques. RAPDs and seed protein patterns were found to be an effective means of identifying accessions that cannot be identified clearly by morphological criteria alone. RAPD and seed protein analysis revealed a clear relationship between observed genetic variation of populations and their geographical distribution. Populations from each region had their own gene pools. Geographical variation was detected in V. segetalis. The degree of genetic divergence between local populations was usually related to proximity. In several locations where wild and weedy populations of different V. sativa agg. taxa grow sympatrically, intermediate forms could be detected at the DNA and protein levels. Both RAPD and seed protein analysis support the view that the V. sativa aggregate consists of 8 taxa warranting recognition at the species level. Several species in this aggregate are evolving intra-specific groups which can readily be detected at the molecular level.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008756420011
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  • 92
    Digitale Medien
    Digitale Medien
    Evaluation of genotype, environment, and genotype-by-environment interaction for capsaicinoids in Capsicum annuum L. (2000)
    Springer
    Euphytica 111 (2000), S. 185-190 
    Details
    ISSN: 1573-5060
    Schlagwort(e): chile ; double haploid ; pepper ; pungency ; stability ; within-genotype variance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The response, in terms of capsaicinoid content, of chile (Capsicum annuum L.) genotypes to different environments was studied. Double haploidlines, an F1 hybrid, and an open-pollinated cultivar estimated the genotype, environment, and genotype-by-environment interaction effect on the total capsaicinoids and on individual capsaicinoids. Significant differences were observed among the genotypes and among genotype-by-environment interactions over the environments. Among the genotypes in an environment, the within-genotype variances were also significantly different. The double haploid line, HDA 207, had low within-genotype variance for individual and total capsaicinoids, with the exception of the isomer of dihydrocapsaicin. Also for HDA 270, the genotype-by-environment interaction was negligible for individual and total capsaicinoids, Indicating stability across environments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003837314929
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  • 93
    Digitale Medien
    Digitale Medien
    The contributions of Ulrich K. Einsle to the taxonomy of the copepoda (2000)
    Springer
    Hydrobiologia 417 (2000), S. 1-10 
    Details
    ISSN: 1573-5117
    Schlagwort(e): taxonomy ; copepods ; Einsle ; chromatin diminution ; enzyme electrophoresis ; Cyclops
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003806912364
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  • 94
    Digitale Medien
    Digitale Medien
    Three species of Tobrilidae (Nematoda: Enoplida) from Li River at Guiling, China (2000)
    Springer
    Hydrobiologia 421 (2000), S. 77-90 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Tobrilidae ; new record ; Nematoda ; taxonomy ; China
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Eutobrilus annetteae Joubert & Heyns, 1979 with its male reported for the first time, Semitobrilus pellucidus (Bastian, 1865) Tsalolichin, 1983, and Epitobrilus allophysis(Steiner, 1919) Tsalolichin, 1996 are described from the Li River at Guiling, China. The male of Eutobrilus annetteae is characterized by lots of crystalloids inside body, almost straight spicules about one anal body diameter long and seven equally sized supplements. Semitobrilus pellucidus from Guiling shows large variation in body width, position of amphids, form of buccal cavity, distance between denticles, direction of vagina, arrangement of oocytes, and shape of eggs. It is different from other populations in its shorter cephalic setae, less than 60% of head width, in its shorter tail and smaller c′ value. In males, there are 6–9 supplements, reduced and irregulary spaced. Epitobrilus allophysisis characterized by its labial setae longer than 50% of head width, small, posteriorly located ovoid amphid, single egg occupying whole space of uterus and blunt tail tip.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003981807711
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  • 95
    Digitale Medien
    Digitale Medien
    Subgeneric differentiation within Kurzia (Crustacea: Anomopoda: Chydoridae) and a new species from Central America (2000)
    Springer
    Hydrobiologia 421 (2000), S. 165-178 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Kurzia ; Crustacea ; Anomopoda ; Chydoridae ; taxonomy ; distribution ; Cladocera
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The genus Kurzia is divided into two subgenera: Kurzia s. str. and Rostrokurzia n. subg. Subgenus Kurzia includes Kurzia (K.) latissima Kurz, 1874, with a palearctic -, Kurzia (K.) polyspina n. sp. with a neotropic - , and Kurzia (K.) cf. media (Birge, 1879) with a nearctic distribution. Rostrokurzia includes Kurzia (R.) longirostris Daday, 1898 (pantropical distribution), and Kurzia (R.) brevilabris Rajapaksa & Fernando, 1986, from subtropical and tropical Asia. Kurzia latissima Kurz, 1874, from Central Europe is redescribed in detail.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003919712255
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  • 96
    Digitale Medien
    Digitale Medien
    New and little known Nematodes (Monhysteroida, Nematoda) from the Strait of Magellan and the Beagle Channel (Chile) (2000)
    Springer
    Hydrobiologia 429 (2000), S. 9-23 
    Details
    ISSN: 1573-5117
    Schlagwort(e): taxonomy ; marine nematodes ; Sabatieria ; Metacomesoma ; Paramonhystera ; Siphonolaimus ; the Strait of Magellan ; Chile
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Six species of Monhysteroida are described from the Strait of Magellan and the Beagle Channel, Chile. Three species of which, Sabatieria heipi n. sp., Paramonhystera geraerti n. sp. and Siphonolaimus smetti n. sp., are new to science. Sabatieria heipi n. sp. is characterised by a body length of 1529–1934 μm, cuticle punctuations with lateral differentiation; cephalic setae 5 μm long, amphids spiral with 4.0–4.2 turns, 10–11 μm in diameter; spicules 76 μm (2.1 anal body diameter), with a 6 μm projection in the ventral distal extremity, 11 minute precloacal supplements; tail 3.7–4.7 anal body diameter (abd) long with enlarged tip. Paramonhystera geraerti n. sp. is characterised by a body size of 705–767 μm; head diameter 12 μm, the cephalic setae 6 μm; amphids circular, 9–10 μm in diameter; spicules slender 108–116 μm (5.6 abd) long, 5 precloacal supplements; and tail 4.0–5.2 abd. Siphonolaimus smetti n. sp. is characterised by the long spear (40–45 μm), head diameter 11–12 μm, amphids circular, 12–13 μm in diameter or 50–57% of corresponding body diameter; the spicules 55 μm and 1.5 abd; tail conical, 2.8 abd (males) and 4.0 abd (females) long. Three other species, i.e. Metacomesoma cyatholaimoides Wieser, 1954, Paramonhystera biforma Wieser, 1956 and P. megacephala (Steiner, 1916) are redescribed. A key of all known species of Paramonhystera is proposed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003995005971
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  • 97
    Digitale Medien
    Digitale Medien
    Two new species of Mesocyclops from southern China and notes on the genus Mesocyclops in China (2000)
    Springer
    Hydrobiologia 429 (2000), S. 115-131 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Mesocyclops mariae n.sp. ; Mesocyclops shenzhenensis n. sp. ; Guangxi ; Guangdong ; China ; taxonomy ; distribution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Two new Mesocyclops species, M. mariae n. sp. and M. shenzhenensisn. sp., are described from southern China, the former species from Guangxi province, the latter from Guangdong province. Both species have setules on the medial margin of the caudal rami. Compared with each other, there are some conspicuous differences, such as the spinule pattern of the antenna basipodite, the structure of receptaculum seminis, the armature of coxopodite and basipodite of P4 and the armature of the caudal rami. The paper also compares the two new species with their supposedly closest relatives, M. pseudospinosus Dussart & Fernando, 1988, M. leuckarti(Claus, 1857) and M. pehpeiensisHu, 1943. In addition, other species of Mesocyclops in China are discussed and a key to 10 Chinese species of Mesocyclops is provided.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004028731322
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  • 98
    Digitale Medien
    Digitale Medien
    A review on the occurrence and taxonomy of heterotrophic protists in extreme acidic environments of pH values ≤ 3 (2000)
    Springer
    Hydrobiologia 433 (2000), S. 153-156 
    Details
    ISSN: 1573-5117
    Schlagwort(e): acid ; taxonomy ; protists ; ciliate ; flagellate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The occurrence and some important taxonomic problems of heterotrophic protists from extremely acidic (pH ≤3) environments are briefly discussed. Almost all information on the occurrence of heterotrophic protists from extremely acidic environments is restricted to acid mine drainage (AMD) or streams influenced by AMD. Most of the information is provided for ciliates. Very little information is available on the occurrence of flagellates, rhizopods and heliozoa in this environment. Within the ciliates Urotricha, Vorticella and Oxytricha dominate in acidic mining lakes. Actinophrys sp. is the most important heliozoan in these environments. There are many taxonomic problems which are not solved so far. Live observations and taxonomic methods adapted to the extreme chemical matrix are necessary for correct identification.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004039309694
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  • 99
    Digitale Medien
    Digitale Medien
    Taxonomic re-evaluation of Aphanizomenon flos-aquae NH-5 based on morphology and 16S rRNA gene sequences (2000)
    Springer
    Hydrobiologia 438 (2000), S. 99-105 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Aphanizomenon ; Cyanobacteria ; 16S rRNA ; morphology ; sequences ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The taxonomy of Aphanizomenon flos-aquae strain NH-5, a producer of cyanotoxins, was re-evaluated by comparison with six other Aphanizomenon strains using morphological characteristics and 16S rRNA gene sequences. Strain NH-5 was concluded to be improperly identified as Aph. flos-aquae based upon (1) lack of bundle formation in the trichomes, (2) location of akinetes next to heterocytes, (3) lower similarities (less than 97.5%) in the 16S rRNA gene sequences relative to Aph. flos-aquae strains, and (4) comparison within a phylogenetic tree constructed from 16S rRNA gene sequences. The Aphanizomenon strains investigated in this study are classified to four morphological groups as described by the classical taxonomy of Komárek & Kovácik (1989). This classification was supported from the phylogenetic results of 16S rRNA gene sequences. This study also discusses the generic boundaries between Aphanizomenon and Anabaena.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004166029866
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  • 100
    Digitale Medien
    Digitale Medien
    Morphological variation of four planktic nostocalean cyanophytes – members of the genus Aphanizomenon or Anabaena? (2000)
    Springer
    Hydrobiologia 438 (2000), S. 107-116 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Cyanophyta/Cyanobacteria ; Aphanizomenon ; Anabaena ; taxonomy ; morphology of trichomes ; heterocytes and akinetes ; Slovakia ; Austria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Morphological variation of trichomes, heterocytes and akinetes in four species classified into the nostocalean genera Aphanizomenon Morren ex Bornet et Flahault or Anabaena Bory (Cyanophyta/Cyanobacteria) was studied from natural samples by LM and illustrated by drawings and micrographs. All investigated species, Aphanizomenon gracile (Lemmerm.) Lemmerm., A. aphanizomenoides (Forti) Komárek et Horecká, Anabaena bergii Ostenfeld, A. minderi Huber-Pestalozzi, occur in the plankton as solitary trichomes, similar to many representatives of the genus Anabaena. Main generic diagnostic characters of Aphanizomenon and Anabaena are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004118213936
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