Petrozavodsk State University

Intestinal microbiome of commercial aquatic species is an important fish farming factor that prevents or reduces economic losses. Heterotrophic bacteria that inhabit intestinal mucosa are involved in digestion, vitamin synthesis, immune modulation, and resistance to pathogens. Age-related changes in the composition of heterotrophic bacterial flora affect health status, nutrient absorption efficiency, and growth rate during ontogenesis. Most studies focus on the luminal microbiota, while the mucosal layer remains understudied despite its reliable impact on the immune system. The current lack of data on the agerelated bacterial dynamics limits the development of age-specific diet strategies and disease prevention. This article presents data on the correlation between the age of rainbow trout (Parasalmo mykiss (Walbaum, 1792)) and the composition of cultured heterotrophic microflora. The research featured 40 fish aged from one to two years and grown on fish farms in the Republic of Karelia, Russia. The bacteria isolated from their intestinal mucosa were identified using standard microbiological methods. The analysis involved the morphotype and biochemical activity, as well as the tinctorial and cultural characteristics of the isolates. The species identification relied on the MALDI-TOF technology. The indices of dominance (Simpson, Berger-Parker), evenness (Pielou), diversity (Shannon), and richness (Margalef, Menhinick) made it possible to reveal that the heterotrophic component of the rainbow trout intestinal bacteria was a stable microbial community with a predominance of Bacillaceae and Enterobacteriacae enterobacteria, as well as Gram-negative non-fermentative bacteria. The index values corresponded to moderate alpha-diversity, which is typical of natural communities that tend to combine several abundant species with some rare taxa. These results may help develop a scientific system for managing the gastrointestinal microflora of commercial fish to improve their health and productivity.

Respiratory activity is a direct and interpretable physiological channel for wearable stress and affective-state recognition, yet many studies emphasize classification accuracy without identifying which respiratory properties separate different states. This work reframes RESP-based recognition as a joint predictive and explanatory problem. Using the chest respiratory channel of the WESAD dataset, we analyze 60 s windows under leave-one-subject-out validation and combine two complementary branches: compact raw-signal one-dimensional convolutional neural networks (1D-CNNs) and physically grouped handcrafted respiratory signatures. The primary application task is binary stress versus non-stress detection, while baseline, stress, amusement, and meditation are additionally analyzed in a one-vs-rest setting to reveal state-specific respiratory markers. The feature space is organized into respiratory timing, breath-to-breath variability, waveform statistics, spectral/time–frequency descriptors, and autocorrelation/nonlinear predictability descriptors, with the raw 60 s signal treated as a sixth representation for the CNN branch. We introduce autocorrelation transition lags (Zpm/Zmp) as interpretable markers of respiratory correlation scale and separately evaluate exploratory forecast-error-growth/Lyapunov-like descriptors. In the final CNN refit setting, the raw-signal model achieved the strongest stress-vs-rest performance (accuracy 96.72%, macro-F1 95.30%, MCC 90.61%). In contrast, compact feature models were stronger for baseline (MCC 65.34%), amusement (MCC 35.69%), and especially meditation (MCC 88.65%). Strict nested reanalysis of the auxiliary Top-20 stress search yielded mean MCC=82.29% versus 85.45% originally, indicating modest selection optimism. These results show that CNNs are most useful for the practical stress detector, whereas interpretable respiratory signatures provide stronger and more physiologically transparent state-specific markers for several non-stress conditions.

The structural characteristics, optical properties and growing features of laser LiNbO3:Er(0.16–3.1 wt

In this paper we study some problems of the canonical harmonic analysis on the field ℚ_p of p -adic numbers. The main elements of the canonical harmonic analysis on ℚ_p are canonical Fourier integral transforms, canonical generalized translation operators and canonical convolution products for functions on ℚ_p . We consider various results of the canonical harmonic analysis for functions from Lebesgue spaces L^ρ(ℚ_p) , 1≤ρ≤∞ . Basic concepts of the canonical harmonic analysis on ℚ_p are expand to generalized functions (or distributions), among them the canonical Fourier transforms on ℚ_p , the generalized translation operators on ℚ_p and others. The analogues of various results of classical harmonic analysis, including analogues of the Paley-Wiener-Schwartz theorems, are proved. We introduce a canonical convolution product on ℚ_p for usual and generalized functions and establish some of its properties.

Ixodes (Exopalpiger) trianguliceps Birula, 1895 is a three-host tick with a primitive non-nidicolous type of parasitism. They encounter hosts outside nests or burrows—in the topsoil, floor, or the ground vegetation layer. The principal hosts for the ticks in all active phases are small mammals of the orders Eulipotyphla and Rodentia. At present, I. trianguliceps has a wide Palearctic distribution. Russian Karelia, where the tick occurs throughout the territory, is the northern part of the species’ range. The aim of this study was to estimate the abundances of I. trianguliceps larvae, nymphs, and adults that parasitize small mammals in mid-boreal Karelia. Surveys were carried out at a field research station of the Institute of Biology of the Karelian Research Centre of the Russian Academy of Sciences (Vlg. Gomselga, Karelia, N 62.068°, E 33.959°) between 2011 and 2024. A total of 2237 host individuals were captured, yielding 1165 larvae, 378 nymphs, and 24 adults of I. trianguliceps. Tick larvae parasitized small mammals in all the surveyed months. Nymphs were primarily collected between May and September, and adult I. trianguliceps—in July. During a season, small mammals provide nourishment for 642 larvae, 133 nymphs, and 6 females of I. trianguliceps per average hectare of the study area. Our estimates of the tick abundance can be used to assess the species’ survival rates over the life cycle. They indicate that the survival rates of I. trianguliceps through phase transitions in mid-boreal Karelia will be around 27