The Study of Cicadas in the Conditions of the Fergana Valley of Uzbekistan

The article presents materials on the study of the cicadas Laodelphax striatellus Fall. and Muirodelphax aubei Perr.in the Fergana Valley, their morphological and biological characteristics, systematic position, distribution, harmfulness, food connections and peculiarities of their diagnosis. As I.D. Mityaev points out [1], the useful value of cicadas for humans is very insignificant. There is evidence that some peoples eat large singing cicadas, considering them medicinal, or keep cicadas in cages for the sake of their peculiar singing. It is proved that some species of cicadas, in places of their mass reproduction, play a significant role in the permeability of moisture and aeration of the soil, the underground work of their larvae. Larvae and imago of cicadas are a source of food for many animals and they play a certain role in biocenoses. Some species, due to their low abundance and low harmfulness, are not of great practical importance for humans. Most of the cicadas are pests of various agricultural plants [2, pp. 146-150]. As noted by D.A. Azimov, without deep knowledge of the fauna and development of the taxonomy of insects, as well as other groups of fauna and vegetation, it is impossible to solve further problems of protection and rational use of useful forms, as well as organization of plant protection [3, pp. 54-55]. Therefore, the study of cicadas and their diagnosis is not only theoretical, but also practical.

Harmful Cicada Families Tettigometridae Of The Fergana Valley

The article presents materials on the study of cicadas Psammotettix striatus (L.) and Psammotettix dubovskyi Vilb. in Fergana Valley, their morphological and biological abilities, systematic position, distribution, harmfulness, food connections and peculiarities their diagnosis.

Thickness accuracy of sash gang sawing

Thin lamellae, corresponding to the layer components of structural glued members, i.e. 2-ply or 3-ply glued parquet, can be manufactured in re-sawing operations of kiln-dried wood blocks. These must be prepared with high dimensional accuracy and adequate surface quality following specific technical requirements for lamellae thickness variations, especially in the upper layers of the glued composite parquet. The accuracy of oak lamellae thickness was examined here for a re-sawing process performed on the sash gang saw. A series of cutting tests were carried out in sawmill production conditions. The overall objective for these observations was to determine an effect of both the cumulative time of sawing (progress of the tool wear) and the lamella position (distribution of lateral forces) on the dimensional accuracy of production. Lamellae size control was conducted following the Brown methodology. Detailed within-board, between-board, and total sawing standard deviations for the examined lamellae positions in the gang were determined. The obtained results revealed that outermost lamellae are more subjected to dimensional inaccuracy than lamellae from the centre of the sawn block or frieze.

Phylogenetic Analysis of HIV-1 Genomes Based on the Position-Weighted K-mers Method

HIV-1 viruses, which are predominant in the family of HIV viruses, have strong pathogenicity and infectivity. They can evolve into many different variants in a very short time. In this study, we propose a new and effective alignment-free method for the phylogenetic analysis of HIV-1 viruses using complete genome sequences. Our method combines the position distribution information and the counts of the k-mers together. We also propose a metric to determine the optimal k value. We name our method the Position-Weighted k-mers (PWkmer) method. Validation and comparison with the Robinson–Foulds distance method and the modified bootstrap method on a benchmark dataset show that our method is reliable for the phylogenetic analysis of HIV-1 viruses. PWkmer can resolve within-group variations for different known subtypes of Group M of HIV-1 viruses. This method is simple and computationally fast for whole genome phylogenetic analysis.