Haemogregarina bigemina Laveran et Mesnil, 1901 was examined in marine fishes and the gnathiid isopod, Gnathia africana Barnard, 1914 in South Africa. Its development in fishes was similar to that described previously for this species. Gnathiids taken from fishes with H. bigemina, and prepared sequentially over 28 days post feeding (d.p.f.), contained stages of syzygy, immature and mature oocysts, sporozoites and merozoites of at least three types. Sporozoites, often five in number, formed from each oocyst from 9 d.p.f. First-generation merozoites appeared in small numbers at 11 d.p.f., arising from small, rounded meronts. Mature, second-generation merozoites appeared in large clusters within gut tissue at 18 d.p.f. They were presumed to arise from fan-shaped meronts, first observed at 11 d.p.f. Third-generation merozoites were the shortest, and resulted from binary fission of meronts, derived from second-generation merozoites. Gnathiids taken from sponges within rock pools contained only gamonts and immature oocysts. It is concluded that the development of H. bigemina in its arthropod host illustrates an affinity with Hemolivia and one species of Hepatozoon. However, the absence of sporokinetes and sporocysts also distances it from these genera, and from Karyolysus. Furthermore, H. bigemina produces fewer sporozoites than Cyrilia and Desseria, although, as in Desseria, Haemogregarina (sensu stricto) and Babesiosoma, post-sporogonic production of merozoites occurs in the invertebrate host. The presence of intraerythrocytic binary fission in its fish host means that H. bigemina is not a Desseria. Overall it most closely resembles Haemogregarina (sensu stricto) in its development, although the match is not exact.
We studied a natural infection of the oligochaete Branchiura sowerbyi Beddard, 1892 with the Raabeia-type actinosporean stage of Myxobolus lentisuturalis Dyková, Fiala et Nie, 2002 which infected goldfish Carassius auratus auratus (L.) in Italy, using molecular analysis of the SSU rRNA gene. The existence of intraoligochaete development shows that this parasite follows the life-cycle pattern described by Wolf and Markiw (1984) for Myxobolus cerebralis. Histological examinations of the goldfish infected by M. lentisuturalis showed at low magnification the presence of two bilateral crescent-shaped masses in the dorsal epaxial muscle. These lesions were not circumscribed, presented irregular edges and infiltrated the underlying bundles of skeletal muscle and interstitial tissue. At higher magnification, disappearance of muscle fibres and substitution of the muscle tissue with Myxobolus spores and plasmodia were observed.
The sanguinicolids Paracardicoloides yamagutii Martin, 1974 and Plethorchis acanthus Martin, 1975 were obtained from their definitive hosts, Anguilla reinhardtii Steindachner and Mugil cephalus Linnaeus (respectively) in the tributaries of the Brisbane River, Queensland, Australia. Two putative sanguinicolid cercariae were collected from a hydrobiid gastropod, Posticobia brazieri Smith, in the same waters. The two cercariae differ markedly in size and the form of their sporocysts. Both putative cercariae develop in the digestive gland of Po. brazieri. The ITS2 rDNA region from these sanguinicolids and a Clinostomum species (utilised as an outgroup due to the close morphological similarities between the cercarial stages of the Clinostomidae and the Sanguinicolidae) were sequenced and aligned. Comparison of the ITS2 sequences showed one cercaria to be that of P. yamagutii. This is the first sanguinicolid life history determined by a molecular method. P. yamagutii is the fourth sanguinicolid known to utilise a freshwater hydrobiid gastropod as its intermediate host. ITS2 rDNA is effective in distinguishing sanguinicolids at the species level.
Paola Bertoli, Veronica Grembi., Obsahuje bibliografii a bibliografické odkazy., České resumé, and Vydává: Univerzita Karlova, Centrum pro ekonomický výzkum a doktorské studium, Národohospodářský ústav AV ČR
A key stage in the design of an effective and efficient genetic algorithm is the utilisation of dornain specific knowledge. Once appropriate features have been identified, genetic operators can then be designed which inanipulate these features in well defined ways. In particular, the crossover operátor is designed so as to preserve in any offspring features cominon to both parental solutions and to guarantee that ordy features that appear in the parents appear in the offspring. Forma analysis [1] provides a well-defined frarnework for such a design process.
In this paper we consider the class of bisection problems. Features proposed for set recombination [2] are shown to be redundant when applied to bisection problems. Despite this inherent redundancy, approaches based on such features háve been successfully applied to graph bisection problems [3].
In order to overcome this redundancy and to obtain performance gains over previous genetic algorithm based approaches to graph bisection a natural choice of features is one based on node pairs. However, such features result in a crossover operator that displays degenerative behaviour and is of no practical use.
Utilization of a magnetic force can be found in many mechatronic applications, where e.g. a slender beam or plate is subjected to static magnetic force generated by an electromagnetic actuator consisting of a solenoid wound on a ferromagnetic core and a ferromagnetic armature, fixed to the beam. The static magnetic force, acting perpendicularly onto the beam, causes sag (downwards bending) of the beam. If the magnitude of the magnetic force surpasses some threshold value the armature and hence the beam is completely attracted to the core of the solenoid. For small detections the mathematical expression of the magnetic force can be linearised and approximated by a polynomial dependence on the distance to the electromagnet. In practical application, it is important to analyse the nature of the sag and to determine the limits of the linear approxmation, as well as the limits leading to the full attraction to the electromagnet. The mathematical generalisation of the sag is valid for electrostatic force between planar electrodes, too. and Obsahuje seznam literatury
For an ordered set W = {w1, w2, . . . , wk} of k distinct vertices in a nontrivial connected graph G, the metric code of a vertex v of G with respect to W is the k-vector code(v) = (d(v, w1), d(v, w2), . . . , d(v, wk)) where d(v, wi) is the distance between v and wi for 1 6 i 6 k. The set W is a local metric set of G if code(u) 6= code(v) for every pair u, v of adjacent vertices of G. The minimum positive integer k for which G has a local metric k-set is the local metric dimension lmd(G) of G. A local metric set of G of cardinality lmd(G) is a local metric basis of G. We characterize all nontrivial connected graphs of order n having local metric dimension 1, n − 2, or n − 1 and establish sharp bounds for the local metric dimension of a graph in terms of well-known graphical parameters. Several realization results are presented along with other results on the number of local metric bases of a connected graph.
The present article tackles the subject of the location of the Central Hall in the Egyptian temples of the Ptolemaic period. According to the texts of the temples, the hall in question was situated between the Sanctuary and the Hall of Offerings. A hall with such a strategic position should have been used by the ancient Egyptians to take advantage of its features. Hence, four temples have been investigated: Edfu, Dendera, Philae and Kom Ombo. However, there were earlier theories concerning the location of the Central Hall and these have to be reconsidered. Recently, with the work conducted by Prof. J. F. Quack on the papyri of the Book of the Temple, there has been an enormous amount of information about the description of the ideal temple and its lay out and, in particular, the location of the Central Hall. Since it is a guidebook for the ideal temple, the information implies that it might have been followed or at least taken into consideration during the planning of the temples.
The Cauchy problem for a stochastic partial differential equation with a spatial correlated Gaussian noise is considered. The ''drift'' is continuous, one-sided linearily bounded and of at most polynomial growth while the “diffusion” is globally Lipschitz continuous. In the paper statements on existence and uniqueness of solutions, their pathwise spatial growth and on their ultimate boundedness as well as on asymptotical exponential stability in mean square in a certain Hilbert space of weighted functions are proved.
Let X be a Stein manifold of complex dimension n\geqslant 2 and \Omega \Subset X be a relatively compact domain with C^{2} smooth boundary in X. Assume that Ω is a weakly q-pseudoconvex domain in X. The purpose of this paper is to establish sufficient conditions for the closed range of \overline \partial on Ω. Moreover, we study the \overline \partial -problem on Ω. Specifically, we use the modified weight function method to study the weighted \overline \partial -problem with exact support in Ω. Our method relies on the L^{2} -estimates by Hörmander (1965) and by Kohn (1973)., Sayed Saber., and Obsahuje seznam literatury