Distribution records of aphids (Hemiptera: Phylloxeroidea, Aphidoidea) associated with main forest-forming trees in Northern Europe

We report records of 25 species of aphids collected from four species of woody plants (Pinus sylvestris, Picea abies, Betula pubescens and B. pendula) at 50 study sites in Northern Europe, located from 59° to 70° N and from 10° to 60° E. Critical evaluation of earlier publications demonstrated that in spite of the obvious limitations of our survey, the obtained information substantially contributed to the knowledge of the distribution of aphids in North European Russia, including Murmansk oblast (103 species recorded to date), Republic of Karelia (58 species), Arkhangelsk oblast (37 species), Vologda oblast (17 species) and Republic of Komi (29 species). We confirm the occurrence of Cinara nigritergi in Southern Karelia; Pineus cembrae, Cinara pilosa and Monaphis antennata are for the first time recorded in Norway

The Implementation of the Feedback Principle in Science and Technics

In this study positive and negative influence of the feedback have been examined. A feedback principle in the alternating current amplifier and in the speed regulator of the turbine rotation was described. The main conclusion of the positive and negative effect was obtained. Negative feedback worsens the properties of an object, reducing a strengthening factor, delaying regulatory action. Positive feedback considerably raises device work stability. This research will enable to identify the importance and effectiveness of the feedback principle in science and technics

On deep speaker embeddings for text-independent speaker recognition

We investigate deep neural network performance in the textindependent speaker recognition task. We demonstrate that using angular softmax activation at the last classification layer of a classification neural network instead of a simple softmax activation allows to train a more generalized discriminative speaker embedding extractor. Cosine similarity is an effective metric for speaker verification in this embedding space. We also address the problem of choosing an architecture for the extractor. We found that deep networks with residual frame level connections outperform wide but relatively shallow architectures. This paper also proposes several improvements for previous DNN-based extractor systems to increase the speaker recognition accuracy. We show that the discriminatively trained similarity metric learning approach outperforms the standard LDA-PLDA method as an embedding backend. The results obtained on Speakers in the Wild and NIST SRE 2016 evaluation sets demonstrate robustness of the proposed systems when dealing with close to real-life conditions.Comment: Submitted to Odyssey 201

Harmonic generation enhancement due to interaction of few-cycle light pulses in nonlinear dielectric coating on a mirror

We theoretically investigate reflection of a few-cycle light pulse from a mirror with nonlinear dielectric coating. We employ a nonlinear equation that describes spatiotemporal evolution of a few-cycle light pulse with a broad spectrum that lies in the transparency range of nonlinear dielectric media. This model is formulated directly for the electric field without slowly varying amplitude approximation. Analytical and numerical analysis shows that counter-propagating wave interactions in thin films can strongly enhance or suppress third harmonic generation of the central frequency, whereas this effect is neglected in the framework of slowly varying amplitude approximation

Mixed electromagnetically and self-induced transparency

We show that application of self-induced transparency (SIT) solitons as a driving field in V -type electromagnetically induced transparency (EIT) leads to "mixed induced transparency" (MIT) that nicely combines the best features of both SIT and EIT

Evaluating the effect of culture filtrate of Trichoderma harzianum on the seed germination and seedling growth of Pinus sylvestris

Researchers are increasingly drawn to exploring additional potential advantages of Trichoderma spp. as the use of these microorganisms in agricultural and forestry applications, known for their notable biological activities, continues to gain popularity. In this work the isolate of Trichoderma harzianum was tested to evaluate its efficacy on the germinating of the common pine seeds and additionally, how growing the fungi on different mediums can affect its biological activities. Findings in this work proves that Trichoderma can grow differently in various media and have diverse sporophytes that differ morphologically. Moreover, using the culture filtrate of Trichoderma harzianum can enhance the germination process of the seeds and the growth of the seedlings

Propagation and interaction of ultrashort electromagnetic pulses in nonlinear media with a quadratic-cubic nonlinearity

Propagation of extremely short unipolar pulses of electromagnetic field ("videopulses") is considered in the framework of a model in which the material medium is represented by anharmonic oscillators (approximating bound electrons) with quadratic and cubic nonlinearities. Two families of exact analytical solutions (with positive or negative polarity) are found for the moving solitary pulses. Direct simulations demonstrate that the pulses are very robust against perturbations. Two unipolar pulses collide nearly elastically, while collisions between pulses with opposite polarities and a small relative velocity are inelastic, leading to emission of radiation and generation of a small-amplitude additional pulse.Comment: 12 pages, 10 figure

Spatial heterogeneity of cutaneous blood flow respiratory-related oscillations quantified via laser speckle contrast imaging

LSCI technique provides experimental data which can be considered in the context of spatial blood flow coherency. Analysis of vascular tone oscillations gives additional information to ensure a better understanding of the mechanisms affecting microvascular physiology. The oscillations with different frequencies are due to different physiological mechanisms. The reasons for the generation of peripheral blood flow oscillations in the 0.14–0.6 Hz frequency band are as follows: cardio-respiratory interactions, pressure variations in the venous part of the circulatory system, and the effect of the sympathetic nervous system on the vascular tone. Earlier, we described the spatial heterogeneity of around 0.3 Hz oscillations and this motivated us to continue the research to find the conditions for the occurrence of spatial phase synchronization. For this purpose, a number of physiological tests (controlled respiration, breath holder, and venous occlusion tests) which influence the blood flow oscillations of 0.14–0.6 Hz were considered, an appropriate measurement system and the required data processing algorithms were developed. At spontaneous respiration, the oscillations with frequencies around 0.3 Hz were stochastic, whereas all the performed tests induced an increase in spatial coherence. The protocols and methods proposed here can help to clarify whether the heterogeneity of respiratory-related blood flow oscillations exists on the skin surface