In this paper we introdiice a new approach to the preprocessing (initial setting) of weight vectors and thus a spoed-up of the well-knowri SOM (Kohonen’s, SOFM) neural network. The idea of the method (we call it Prep through this paper) consists in spreading a small lattice over the pattern space and consequently completing its inner meshes and boundaries to obtain a larger lattice. This large lattice is then tuned by its training for a short time. To justify the speed up of the Prep method we give a detailed time analysis. To demonstrate the suggested method we show its abilities on several representative examples.
The genera Preptetos Pritchard, 1960 and Neopreptetos Machida, 1982 are redefined. The following species are described and/or recorded from marine fishes. From the Great Barrier Reef: Preptetos caballeroi Pritchard, 1960 in Naso annula-tus, N. brevirnslris and N. vlamingii·, P. xesuri (Yamaguti, 1940) in Zebrasoma veliferum and Z. scopas; Preptetos cannoni Barker, Bray et Cribb, 1993 in Siganus dolialus and S. fuscescens', Preptetos laguncula sp. n. in Naso unicornis (type-host); P. impar sp. n. in Lutjanus erythropterus (type-host) and L. malabaricus·, Neopreptetos arusettae Machida, 1982 in Pomacanthus semicirculatus·, and N. kurochkini (Toman, 1989) in Chaetodontoplus meredithi. From southwestern Australia: Preptetos rotto sp. n. in Nelusetta ayraudi (type-host), Neosebastes pandus, Oplegnathus woodwardi and Pagrus auratus. The new combination Preptetos trulla (Linton, 1907) (originally Distomum then Lepocreadium) is made and the species Lepocreadium areolatum (Linton, 1900) is considered likely to belong in Preptetos.
An inbred strain of a newly isolated spontaneous albino mutant of Schistocerca gregaria (Forsk.) was examined for the presence of the neuropeptide [His7]-corazonin by immunocytochemical and mass spectrometric methods. It was concluded that this peptide is definitely present in a limited number of neurosecretory cells in the pars lateralis as well as in the corpora cardiaca (CC). Injection of either synthetic [His7]-corazonin or of extracts of CC of the normal coloured phenotype of S. gregaria failed to induce darkening of the cuticle, while albino Locusta migratoria, used as a positive control, turned dark. The conclusion is that the cause of albinism in the new S. gregaria albino is probably due to a defect in the receptor system for [His7]-corazonin or in the biosynthetic pathway of melanin.
Some free-living amoebae are a potential threat to human health. The best known species are those of the genus Acanthamoeba Volkonsky, 1931, which cause Acanthamoeba keratitis, granulomatous amoebic encephalitis and other forms of tissue inflammation. The aim of the present study was to search for potential pathogenic genotypes of free-living amoeba in the sand in children's playgrounds. Our results confirmed that free-living amoebae were present in all examined playgrounds. Sequences of the 18S rDNA have shown that all isolated potentially pathogenic strains of amoebae belong to genotype T4 of Acanthamoeba. The potential pathogenicity of isolates was confirmed on mice. The presence of pathogenic amoebae in the examined sand may be a potential source of human infection., Marcin Cholewiński, Piotr Solarczyk, Monika Derda, Agnieszka Wojtkowiak-Giera, Edward Hadaś., and Obsahuje bibliografii
We studied the structure of calls emitted by the echolocating fruit bat Rousettus leschenaulti (Megachiroptera:Pteropodidae) while flying inside a free-flight room. The echolocation sounds consists of both single as well as double clicks, with single clicks emitted either in the beginning or at the end of click sequences. The duration of clicks was brief, about 1.6 ms and most of the acoustic energy is between 18 to 32 kHz. The use of simple, brief impulsive clicks and the reduction of interpulse interval and duration, when approaching the sides of the walls suggest that they have a good capability of obstacle avoidance as similar to microchiropteran bats. Furthermore, the production of both single as well as double clicks like cave swiftlets in orientation flights has an implication for the evolution of echolocation in bats.
The gut microbiota provides a wide range of beneficial functions for the host, and has an immense effect on the host’s health status. The presence of microbiome in the gut may often influence the effect of an orally administered drug. Molecular mechanisms of this process are however mostly unclear. We investigated how the effect of a nonsteroidal drug nabumetone on expression of drug metabolizing enzymes (DMEs) in mice intestine and liver is changed by the presence of microbiota, here, using the germ free (GF) and specific pathogen free (SPF) BALB/c mice. First, we have found in a preliminary experiment that in the GF mice there is a tendency to increase bioavailability of the active form of nabumetone, which we have found now to be possibly influenced by differences in expression of DMEs in the GF and SPF mice. Indeed, we have observed that the expression of the most of selected cytochromes P450 (CYPs) was significantly changed in the small intestine of GF mice compared to the SPF ones. Moreover, orally administered nabumetone itself altered the expression of some CYPs and above all, in different ways in the GF and SPF mice. In the GF mice, the expression of the DMEs (CYP1A) responsible for the formation of active form of the drug are significantly increased in the small intestine and liver after nabumetone application. These results highlight the importance of gut microbiome in processes involved in drug metabolism in the both gastrointestinal tract and in the liver with possible clinical relevance.
The number of colonies of red wood ants (Formica rufa group) in the north western part of Belgium has declined by more than half over the past 20 years. In the study area of 20 × 50 km there are currently only 36 colonies of two species of red wood ants (Formica rufa and F. polyctena). Both species form both monodomous and polydomous colonies. Monodomous F. rufa colonies occur in large areas of open woodland dominated by Pinus sylvestris. The other three types of red wood ant (F. rufa polydomous, F. polyctena mono- and polydomous) occur in clearings or along the margins of small areas of deciduous or mixed woodland. The extinction of red wood ants cannot be attributed to a loss of their main habitat. Their decline in abundance, however, appears to be due to the deterioration in their habitat caused by several factors. Shading by overgrowing shrubs and the closure of the tree canopy, nearby intensive agriculture, urbanisation and use of the forest for recreation are the more important factors threatening and ultimately leading to the extinction of colonies. At poor quality sites there are no or very few nests of Serviformica ants, which initially serve as host ants and are necessary for recolonization by red wood ants. Thus, it is unlikely that these sites will be recolonized. To conserve red wood ants and maintain populations there is an urgent need to undertake certain measures, especially in areas outside nature reserves. For this there is a need to create clearings in the woodland, reduce shading due to overgrowing shrubs and closure of the tree canopy, and mitigate the effects of intensive agriculture, urbanisation and recreation. It is important that the effects of these measures should be monitored.