1,657 research outputs found

    Feeding habits of pacific salmons in the eastern Bering Sea in 2003-2012

    Get PDF
    Change in prey for pacific salmons in the eastern Bering Sea is considered between the periods of relatively warm (2003-2006) and relatively cold (2007-2012) conditions on the base of data obtained in the frames of BASIS research program. In the warm period, mean biomass of the large-sized, medium-sized and small-sized fractions of zooplankton was 287.9, 258.2, and 109.2 mg/m3, respectively. In these conditions, fish prey was the basis of diet for pink salmon (70-68 % of ration), chum salmon (64-84 %) and sockeye salmon (45-87 %). Pink, chum, sockeye, and coho salmons had similar diet with the dominance of juvenile walleye pollock (similarity 70-90 %), in contrast to the diet of chinook salmon (40-70 % similarity with others). In the cold period, the large-sized zooplankton was much more abundant (1094.8 mg/m3 on average) mostly due to higher abundance of Copepoda and Chaetognatha; euphausiids, hyperiids, and pteropods were more abundant, as well. In these conditions, zooplankton, mainly euphausiids Thysanoessa raschii and hyperiids Themisto libellula and T. pacifica , dominated in the diet of plankton-eating salmons: 86-92 % of the ration for pink salmon, 88-92 % for chum salmon, and 74-81 % for sockeye salmon; all these species and chinook juveniles had similar diet (70-80 % similarity). On the contrary, predatory salmons as coho and chinook adults still preyed on fish. Mean daily rations in the warm/cold periods are estimated as 12.1/9.4 % of body weight for sockeye salmon with the length 10-20 cm, 8.6/7.3 % for sockeye salmon 20-30 cm, 8.3/13.8 % for chum salmon 10-20 cm, 8.6/10.0 % for chum salmon 20-30 cm, and 8.8/10.3 % for pink salmon 10-25 cm. The prevalence of nekton or planktonic food does not affect on daily rhythm of feeding intensity: juvenile salmons feed mainly in the daytime, so they have the maximal index of stomachs fullness in the evening or early night (100-230 ‱, both in the warm and cold periods). Generally, the salmons prefer fish larvae and juveniles in conditions of low zooplankton abundance and large-sized zooplankton in conditions of its high abundance. Selectivity on euphausiids, hyperiids and pteropods is observed only in conditions of high zooplankton abundance and is an indicator of sufficient food supply

    Feeding and food supply of juvenile fishes in the eastern Bering Sea in 2003-2012

    Get PDF
    Feeding of fish juveniles in the eastern Bering Sea is investigated for the periods of 2003-2006 considered as relatively «warm» and 2007-2012 considered as relatively «cold». Small- and medium-sized zooplankton was the dominant prey in the 2003-2006, in particular copepods prevailed in the food of walleye pollock (41.5 %), pacific herring (48.3 %), and sand lance (71.7 %) juveniles, which in turn were the prey for pollock, herring and cod yearlings and other predators. On the contrary, large-sized zooplankton was more abundant in the 2007-2012, so arrowwarms ( Sagitta sp.), large-sized copepods (in particular Calanus marshallae ), euphausiids (mainly Thysanoessa raschii ), hyperiids, and pteropods were the prey for young fish: C. marshallae - for juveniles of pollock (40-45 % by weight) and capelin (32-34 %), Th. raschii - for yearlings of pollock (51 %) and herring (36-46 %), cold-water hyperiid T. libellula - for adult pollock (24 %), juvenile cod (9-18 %) and juvenile herring (9-11 %), whereas portion of fish in the diets was insignificant. In the warm period (2003-2006), juvenile pollock, herring, sand lance and capelin were zooplankton-eaters with the diets similarity 67 %, while yearlings of pollock and juveniles of cod, herring, sandfish, and atka mackerel were fish-eaters preying upon pollock juveniles. In the cold period (2007-2012), the diets of juvenile pollock, juvenile and adult capelin, and juvenile sand lance were also similar at 85-70 % but they preferred large-sized copepods and euphausiids ( C. marshallae and Th. raschii ), while yearlings of pollock, yearlings and adults of herring, and juveniles of sand fish and cod had the diets of 70 % similarity with Th. raschii prevalence. Feeding intensity was high for all species: the mean stomach fullness was 150-200 ‱ for pollock juveniles and yearlings, 200-250 ‱ for cod juveniles, 200-258 ‱ for sand lance juveniles, 302 ‱ for herring juveniles, and 178-250 ‱ for juvenile atka mackerel. The fullness had diurnal rhythm with three peaks: at noon - up to 179 ‱, in evening - up to 213 ‱, and at night - up to 204 ‱ (the data for walleye pollock juveniles in «cold» years only). Daily food ration of juvenile pollock is estimated as 6.7 % of its body weight in the «warm» years and 7.0 % in the «cold» years

    Evaluating the efficiency of the research sector in Russian regions: a dynamic data envelopment analysis

    Get PDF
    The nonparametric method of dynamic data envelopment analysis (DDEA) has become increasingly popular for conducting comparative efficiency evaluations. In recent years, dynamic data envelopment analysis (DDEA), a variant of this method, has gained significant attention. This article applies dynamic analysis to evaluate the efficiency of the research sector in Russian regions. Traditional input variables such as the number of research staff and R&D expenditure are considered, while publication and patent metrics serve as output indicators. The analysis covers a substantial time period, spanning from 2009 to 2020. Notably, the proposed evaluation method incorporates publication quality measures as a carry-over variable, in addition to accumulated R&D expenditure. The study employs dynamic data envelopment analysis to compare the obtained results with previous evaluations of the research and technology sector in Russian regions. The findings demonstrate that the proposed method serves as a valuable ranking technique, enhancing existing evaluations of regions' research and technology potential in terms of efficiency. The article concludes by discussing the prospects and limitations of the method in evaluating and forecasting research and technology profiles of regions

    Ontogenetic Development of Neural and Muscular Rhythmic Activity and Its Regulation in Mammals during Perinatal Period

    Get PDF
    This review covers our recent advantages in studying the ontogenetic aspects of physiological mechanisms underlying regulation of rhythmic behavior. We have revealed that excitation patterns that emerged at early stages of phylogenetic development of life forms contribute greatly to the rhythmic activity of living vertebrates and invertebrates. These patterns govern spontaneous excitation, which is easily observed during the early stage of ontogenesis. The intensity and patterns of rhythmic activity are determined by nature and kinetics of certain metabolic reactions. During perinatal and sometimes postnatal periods (as in prematurely born animals), endogenic rhythmicity of developing physiological structures is strongly pronounced due to relatively stable living conditions. This rhythmic behavior is coordinated within an entire organism. Its integration in multiple systems is driven by amplitude and frequency modulation yielding rhythms of various frequency ranges. Indeed, it is the complex and conjoint functioning of physiological systems that maintains homeostasis in developing organisms. We present the results of our authentic research concerning the evolution and ontogeny of regulatory mechanisms of motor, cardiovascular, and respiratory systems. The aspects of intact and disrupted development are considered, involving the changes in dopaminergic, norepinephrinergic, and cholinergic system activation

    Development of the Asia-Pacific Region: Current Economic Position and Perspective of Information Society

    Get PDF
    The article examines the problems of current economic development in the Asia-Pacific region. It is a condition of the system in which its key parameters are the optimal ratio contributing to the existence and development of the whole system. It was analyzed the changing situation in the Asia-Pacific region based on the main characteristics of the researching complex according to the authors' calculated index. It was identified that in the analyzing period the quantitative and qualitative structure of the group of countries has completely changed. It was also provided the classification of the Asia-Pacific countries based on the current level of their economic development. Thus, because of the differences in the economic dynamics it was identified the main differences in the levels of economic development among the groups of the Asia-Pacific countries. This analysis was conducted for identification of the competitive advantages of the information society in the Asia-Pacific region, as the development of a new society based on "knowledge economy" which will be a priority for a long-term perspective

    Photonics and application of dipyrrinates in the optical devices

    Get PDF
    In this paper spectral-luminescent, lasing, photochemical, and sensory characteristics of a number of Zn(II) and B(III) coordination complexes with dipyrrinates with different structures are presented. We have discussed relations of the structure of investigated compounds and formed solvates with their optical characteristics. The results showed that alkyl substituted dipyrrinates derivatives have excellent luminescent characteristics and demonstrated effective lasing upon excitation of Nd:YAG-laser. They can be used as active media for liquid tunable lasers. Zinc and boron fluoride complexes of dipyrrinates with heavy atoms in structure don't have fluorescence but have long-lived emission due to increased nonradiative intersystem processes in the excited state by the mechanism of a heavy atom. For solid samples based on halogenated complexes was found dependency of the long-lived emission intensity of the oxygen concentration in gas flow. The presence of line segment indicates the possibility of the use of these complexes as a basis for creation of optical sensors for oxygen. Moreover, results of a study of halogen-substituted aza-complexes under irradiation are presented. Such complexes are promising for the creating media for generation of singlet oxygen (1O2), which is important for photodynamic therapy in medicine and photocatalytic reactions in the industry

    Photonics of boron fluoride and zinc dipyrromethene complexes

    Get PDF
    Spectral, photophysical, photochemical characteristics for mononuclear and binuclear dipyrromethenes in complexes with BF2 (BODIPY), bis-BODIPY and bis-helicates ([Zn2(L)2]) are described. The role of substituents (type and location in the ligand) and the medium in which dipyrromethene complexes are placed (solvents, solid-state matrices), the effect of different complexing agents (p- and d-elements) on the photonics of the complexes are discussed. The results of studying the lasing and photochemical properties of complexes under the action of laser irradiation are presented. In addition, for the described complexes the stability in the ground and excited states in protic media are estimated. Based on the analysis of the results discussed possibilities of practical application of these compounds to creating various optical devices

    LEXICAL FEATURES OF BORROWED VOCABULARY OF THE FORMATION PERIOD OF MEDICAL TERMINOLOGY OF DISEASES IN RUSSIA

    Get PDF
    The study complements the information about the nature of the medical term within the framework of historical terminology. Purpose. The article discusses the linguistic features of medical borrowed terms denoting human diseases. Materials and methods. The material was medical scientific texts on surgery and pharmacology of 1835-1899 editions. The analysis used lexico-semantic, etymological and word-formation analysis of vocabulary, a comparative method of linguistic research. Results. The results of the study suggest that by the nineteenth century, the Russian scientific medical terminology of diseases was finally formed in the national language. The basis of the formation are lexical units of Greek-Latin origin, there were also borrowings from Polish, French, and English. Comparative analysis of terms in different languages has shown the presence of a large number of terms-internationalisms. Translated borrowings and calculus were used in the formation of terms. The study revealed the difficulty of proving the formation of terms by calculus. The analysis of medical terms revealed semantic differences in the source language and in the recipient language, which confirms: 1) the artificial nature of the formation of the terminological system, 2) the presence of national specificity of terms denoting diseases. Thus, the results of the study show that with the unity of the laws of human cognition, an individual understanding of the world picture is manifested in each language; the names of diseases formed on the basis of the national language reflect the popular understanding of diseases. Practical implications. The factual material and conclusions of the article can be used both in terminology and in the course of medical education
    corecore