201 research outputs found

    Coupled quantum wires

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    We study a set of crossed 1D systems, which are coupled with each other via tunnelling at the crossings. We begin with the simplest case with no electron-electron interactions and find that besides the expected level splitting, bound states can emerge. Next, we include an external potential and electron-electron interactions, which are treated within the Hartree approximation. Then, we write down a formal general solution to the problem, giving additional details for the case of a symmetric external potential. Concentrating on the case of a single crossing, we were able to explain recent experinents on crossed metallic and semiconducting nanotubes [J. W. Janssen, S. G. Lemay, L. P. Kouwenhoven, and C. Dekker, Phys. Rev. B 65, 115423 (2002)], which showed the presence of localized states in the region of crossing.Comment: 11 pages, 10 figure

    Effect of processing by femtosecond pulsed laser on mechanical properties of submicrocrystalline titanium

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    Effect of femtosecond laser processing on mechanical properties of plates made of submicrocrystalline VT1-0 titanium alloy is studied using active deformation and fatigue testing involving cantilever bendin

    The influence of the drugs “Brovermectin-granulate TM” and “Avesstim TM” on indicators of non-specific resistance of one year-old carp fish infested with monogeneans

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    The article presents data on the study of the influence of the drugs “Brovermectin-granulate TM” and “Avesstim TM” on indicators of non-specific resistance of one-year-old carp fish infested with monogeneans. For conducting experiments, 14 experimental groups were formed (two groups of each species of fish affected by Dactylogyrus lamellatus, Gyrodactylus hypophthalmichtіdis, Eudiplozoon nipponicum ). The fish of the first experimental group were administered “Brovermectin-granulate TM”, and the second experimental group were administerec a complex of drugs “Brovermectin-granulate TM” and “Avesstim TM”. Fish infected with various ectoparasites (Dactylogyrus lamellatus, Gyrodactylus hypophthalmichtіdis, Eudiplozoon nipponicum ) served as controls. Fish of each group were kept in separate aquariums with a capacity of 40 dm3 with artificial aeration at a temperature of 20–22 °С. Their care and feeding was carried out according to the relevant norms and rations. During the entire period of research, the behavior and clinical condition of the fish were observed. The pre-experimental period of acclimatization of annuals was 7 days. The use of the drug “Brovermectin-granulate TM” to one-year-old white carp, crucian carp and scaly carp affected by monogeneans had a stimulating effect on the resistance of their organism. At the same time, the simultaneous use of the specified drug with the immunomodulator “Avesstim TM” contributed to better activation of the humoral link of non-specific immunity in sick fish. To normalize the organism homeostasis, correct metabolism and activate the humoral link of non-specific immunity during a monogenoid invasion of carp, it is recommended to feed them with a combined feed of the drugs “Brovermectin-granulate TM” and the immunomodulator “Avesstim TM”

    Adaptive potential of spring durum wheat (<i>Triticum durum</i> Desf.) under the conditions of Primorsky Territory

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    Background. The research goal was to study spring durum wheat cultivars from different regions of Russia to select those that were most adapted to the conditions of Primorsky Territory and had high yield and grain quality.Materials and methods. The adaptive potential of 16 genotypes was determined through multi-environment trials at the Federal Scientific Center of Agricultural Biotechnology of the Far East named after A.K. Chaika in 2017–2021.Results. Considerable potential for high productivity was revealed in the cultivars: ‘Solnechnaya 573’ (3.9 t/ha), ‘Donskaya elegiya’ (3.8 t/ha), ‘Lyudmila’ (3.8 t/ha), ‘Omskii izumrud’ (3.8 t/ha), and ‘Voronezhskaya 7’ (3.8 t/ha). Cvs. ‘Pamyati Yanchenko’ (–2.1), ‘Zhemchuzhina Sibiri’ (–2.4), and ‘Voronezhskaya 7’ (–2.4) displayed significant stress resistance. ‘Lyudmila’ (4.2) and ‘Donskaya elegiya’ (4.0) had high genetic plasticity and produced high yields in the years with favorable conditions. The adaptability coefficient of cvs. ‘Solnechnaya 573’ (112.5%) and ‘Voronezhskaya 7’ (111.0%) exceeded 100%. ‘Donskaya elegiya’, ‘Lyudmila’, ‘Aleiskaya’, and ‘Voronezhskaya 9’ demonstrated the highest plasticity (bi &gt; 1). The most stable cultivars were ‘Omskii tsirkon’ (S2di – 0.00), ‘Pamyati Yanchenko’ (S2di – 0.02), ‘Voronezhskaya 7’ (S2di – 0.04), ‘Aleiskaya’ (S2di – 0.05), ‘Nikolasha’ (S2di – 0.06), and ‘Omskaya biryuza’ (S2di – 0.08). ‘Voronezhskaya 7’ and ‘Pamyati Yanchenko’ were able to produce an increased yield and had the minimum yield loss under unfavorable conditions (the indicator of the yield stability of the cultivars was 134.9 and 144.8, respectively). ‘Pamyati Yanchenko’ (4.8 and 1.9, respectively) and ‘Voronezhskaya 7’ (3.5 and 2.0, respectively) showed high homeostatic capacity and breeding value.Conclusions. ‘Voronezhskaya 7’ and ‘Solnechnaya 573’ were selected on the basis of complex evaluation for yield and adaptability under the local conditions. They can be recommended for further breeding and production

    Features of Morphometric Changes in Platelets and Red Blood Cells in Women with Various Forms of Hypertensive Disorders in the Third Trimester of Pregnancy

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    Background. Arterial hypertension during pregnancy is accompanied by pronounced changes in microcirculation and hemostasis in the system, the state of which is largely determined by the structural and functional properties of red blood cells and platelets. The study of quantitative and morphometric characteristics of blood cells will expand the existing understanding of their role in the pathogenesis of hypertensive disorders.Aim of the research. To study the quantitative and morphometric indicators of red blood cells and platelets in pregnant women with various forms of hypertensive disorders, on the basis of which to develop an additional method for the diagnosis of preeclampsia. Materials and methods. 237 women in the third trimester of pregnancy were examined. The main group (167 women) included patients with various forms of hypertensive disorders. The comparison group included 70 pregnant women without signs of hypertensive disorders. The characteristic of clinical and anamnestic data of the studied groups is given. A comparative analysis of the number and morphometric parameters of red blood cells and platelets was performed.Results. With moderate and severe preeclampsia, a decrease in the level of red blood cells, hemoglobin and hematocrit was not accompanied by changes in red blood cell indices. In women with preeclampsia, regardless of the presence of chronic arterial hypertension, an increase in the average dry weight, average volume and degree of platelet anisocytosis was detected. In severe preeclampsia and preeclampsia with underlying of  chronic arterial hypertension, an increase in the number of large forms of platelets and their granulocytosis was revealed, and in addition, in severe cases of preeclampsia, a decrease in platelet level was noted.Conclusions. Modern hematological analyzers make it possible to establish the nature of not only quantitative, but also morphometric changes in red blood cells and platelets, thereby complementing the existing understanding of the pathogenetic mechanisms underlying hypertensive disorders in pregnancy. Using average dry platelet mass and average blood pressure may be useful in diagnosing preeclampsia

    Optical Self Energy in Graphene due to Correlations

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    In highly correlated systems one can define an optical self energy in analogy to its quasiparticle (QP) self energy counterpart. This quantity provides useful information on the nature of the excitations involved in inelastic scattering processes. Here we calculate the self energy of the intraband optical transitions in graphene originating in the electron-electron interaction (EEI) as well as electron-phonon interaction (EPI). Although optics involves an average over all momenta (kk) of the charge carriers, the structure in the optical self energy is nevertheless found to mirror mainly that of the corresponding quasiparticles for kk equal to or near the Fermi momentum kFk_F. Consequently plasmaronic structures which are associated with momenta near the Dirac point at k=0k=0 are not important in the intraband optical response. While the structure of the electron-phonon interaction (EPI) reflects the sharp peaks of the phonon density of states, the excitation spectrum associated with the electron-electron interaction is in comparison structureless and flat and extends over an energy range which scales linearly with the value of the chemical potential. Modulations seen on the edge of the interband optical conductivity as it rises towards its universal background value are traced to structure in the quasiparticle self energies around kFk_F of the lower Dirac cone associated with the occupied states.Comment: 30 pages, 10 figure
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