Using the concept of $\mathcal {I}$-convergence we provide a Korovkin type approximation theorem by means of positive linear operators defined on an appropriate weighted space given with any interval of the real line. We also study rates of convergence by means of the modulus of continuity and the elements of the Lipschitz class.
Functioning of plant-aphid-natural enemy interactions may be associated with the structure and composition of withinfield vegetation, neighborhood fields and field borders, and the regional plant community of cropped and noncropped areas. Farmand region-scale vegetation in the wheat-growing area of the North American Great Plains was hypothesized to effect the abundance of two hymenopteran parasitoids, that differ in physiological and behavioral attributes, of the key pest aphid of wheat, Diuraphis noxia (Mordvilko). The parasitoids had greater sensitivity to farm-scale vegetation (wheat strip rotation with or without spring-sown sunflower) than region-scale vegetation (degree of diversification with other crops and wheat fields converted to conservation grasslands). A two-way factorial design of scale (farm- and region-scale) revealed that parasitoid abundance in grass-dominant (homogeneous) areas especially benefited from adding sunflower to the wheat-fallow strip crop rotation. Considerable sensitivity of the analysis was added when adjusting for seasonality of vegetation, revealing that the region-scale effects were most prominent late season. From a management viewpoint, adding sunflower into the wheat production system, especially in relatively homogeneous vegetation regions, tends to promote local parasitoid populations during the summer when spring-sown plants are maturing and wheat is not in cultivation. Contrasting results for A. albipodus and L. testaceipes were consistent with expectations based on behavioral and physiological attributes of the two aphid parasitoid families they represent. Still, the general management interpretation seems robust for the two parasitoids and has relevance to both farm- and region-scale management schemes that are occurring in the wheat production zone of North American Great Plains.
In this paper, a learning algorithm for a novel neural network architecture motivated by Integrate-and-Fire Neuron Model (IFN) is proposed and tested for various applications where a multilayer perceptron (MLP) neural network is conventionally used. It is observed that inclusion of a few more biological phenomenon in the formulation of artificial neural networks make them more prevailing. Several benchmark and real-life problems of classification and function-approximation are illustrated.
The Northern pine processionary moth, Thaumetopoea pinivora (Treitschke, 1834) shows a highly scattered distribution with fragmented populations across Europe. A previous study exploring the postglacial history of T. pinivora defined it as a cold-tolerant relict species and concluded that a progressive reduction of suitable habitats after the postglacial expansion from refugia in the southern Iberian peninsula best explained the distribution and genetic structure of populations of this species. However, recent records, both by us and others, challenge this view. Surprisingly, some of the newly found populations from southern Spain use black pine, Pinus nigra J.F. Arnold as a host plant despite the fact that the typical host of the species, Scots pine, Pinus sylvestris L. occurs in the area. We provide genetic data for one of these recently found southern populations where the larvae feed on P. nigra, and compare this with previously published data on individuals collected on P. sylvestris. This data reveals that populations from different host trees are no more genetically differentiated than populations sharing the same host plant. The findings of a wider diet breadth open the way to widen the search for the still unidentified glacial refugium of T. pinivora, and as such may contribute to a better understanding about how the species has spread across Europe., José A. Hódar, Anna Cassel-Lundhagen, Andrea Battisti, Stig Larsson., and Obsahuje bibliografii
In this paper, a local approach to the concept of g-entropy is presented. Applying the Choquet`s representation Theorem, the introduced concept is stated in terms of g-entropy.
In this paper we establish a new local convergence theorem for partial sums of arbitrary stochastic adapted sequences. As corollaries, we generalize some recently obtained results and prove a limit theorem for the entropy density of an arbitrary information source, which is an extension of case of nonhomogeneous Markov chains.
This paper presents a design tool of impedance controllers for robot manipulators, based on the formulation of Lyapunov functions. The proposed control approach addresses two cha\-llen\-ges: the regulation of the interaction forces, ensured by the impedance error converging to zero, while preserving a suitable path tracking despite constraints imposed by the environment. The asymptotic stability of an equilibrium point of the system, composed by full non\-li\-near robot dynamics and the impedance control, is demonstrated according to Lyapunov's direct method. The system's performance was tested through the real-time experimental implementation of an interaction task involving a two degree-of-freedom, direct-drive robot.
Let $(H,\alpha )$ be a monoidal Hom-Hopf algebra and $(A,\beta )$ a right $(H,\alpha )$-Hom-comodule algebra. We first introduce the notion of a relative Hom-Hopf module and prove that the functor $F $ from the category of relative Hom-Hopf modules to the category of right $(A, \beta )$-Hom-modules has a right adjoint. Furthermore, we prove a Maschke type theorem for the category of relative Hom-Hopf modules. In fact, we give necessary and sufficient conditions for the functor that forgets the $(H, \alpha )$-coaction to be separable. This leads to a generalized notion of integrals.
In this paper a model for the recovery of human and economic activities in a region, which underwent a serious disaster, is proposed. The model treats the case that the disaster region has an industrial collaboration with a non-disaster region in the production system and, especially, depends upon each other in technological development. The economic growth model is based on the classical theory of R. M. Solow (1956), and the full model is described as a nonlinear system of ordinary differential equations.
In this paper, we present a novel quantitative description of intracellular and t-tubular Ca2+ dynamics in a model of rat cardiac ventricular myocyte. In order to simulate recently published data, the model incorporates t-tubular and peripheral dyads and intracellular subspaces, segmentation of the t-tubular luminal volume, reformulation of the inactivation properties of t-tubular land peripheral L-type calcium current (ICa) and a description of exogenous Ca2q+ buffer function in the intracellular space. The model is used to explore activity-induced changes of ion concentration in the intracellular and t-tubular spaces and their role in excitation - contraction coupling in ventricular myocytes. and Obsahuje Appendix se seznamy literatury, užitých zkratek a symbolů