975 research outputs found

    Hypodynamic and hypokinetic condition of skeletal muscles

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    Data are presented in regard to the effect of unilateral brachial amputation on the physiological characteristics of two functionally different muscles, the brachial muscle (flexor of the brachium) and the medial head of the brachial triceps muscle (extensor of the brachium), which in rats represents a separate muscle. Hypokinesia and hypodynamia were studied

    Asymptotics for the number of n-quasigroups of order 4

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    The asymptotic form of the number of n-quasigroups of order 4 is 3n+122n+1(1+o(1))3^{n+1} 2^{2^n +1} (1+o(1)). Keywords: n-quasigroups, MDS codes, decomposability, reducibility.Comment: 15 p., 3 fi

    On the structure of non-full-rank perfect codes

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    The Krotov combining construction of perfect 1-error-correcting binary codes from 2000 and a theorem of Heden saying that every non-full-rank perfect 1-error-correcting binary code can be constructed by this combining construction is generalized to the qq-ary case. Simply, every non-full-rank perfect code CC is the union of a well-defined family of μ\mu-components KμK_\mu, where μ\mu belongs to an "outer" perfect code CC^*, and these components are at distance three from each other. Components from distinct codes can thus freely be combined to obtain new perfect codes. The Phelps general product construction of perfect binary code from 1984 is generalized to obtain μ\mu-components, and new lower bounds on the number of perfect 1-error-correcting qq-ary codes are presented.Comment: 8 page

    Every latin hypercube of order 5 has transversals

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    We prove that for all n>1 every latin n-dimensional cube of order 5 has transversals. We find all 123 paratopy classes of layer-latin cubes of order 5 with no transversals. For each n3n\geq 3 and q3q\geq 3 we construct a (2q-2)-layer latin n-dimensional cuboid with no transversals. Moreover, we find all paratopy classes of nonextendible and noncompletable latin cuboids of order 5.Comment: Supplementary data https://zenodo.org/records/1020402

    Synthesis of di(Imdazolium) and di(Pyrazolium) Salts as Precursors for N-heterocyclic Dicarbene Complexes

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    Alpha,omega-bis(pyrazol-1-yl)alkanes and alpha,omega-bis(imidazol-1-yl)alkanes with spacers consisting of four to ten methylene groups have been prepared from pyrazole, 3,5-dimethylpyrazole or imidazole and corresponding dibromoalkanes in a superbasic medium KOH-DMSO. The proposed method of synthesis allowed the preparation of new flexible bidentate ligands without the need to use toxic solvents and tedious workup procedures. Bis(pyrazol-1-yl)alkanes were further functionalized for their use as precursors for “non-classical” mesoionic N-heterocyclic carbene ligands. One the first step, iodine atoms were introduced to positions 4 of pyrazole rings by oxidative iodination using I[2]-HIO[3] system. On the next step, nitrogen atoms in positions 2 of pyrazole rings were alkylated using several agents. Reaction with methyliodide unexpectedly led to the formation of only mono-alkylated products even after 7 days of refluxing in a neat alkyliodide. Methylation by trimethyloxonium tetrafluoroborate or methyltriflate led to dimethylated products in high yields. Bis(imidazol-1-yl)alkanes were easily alkylated by methyliodide to give di(imidazolium) salts – precursors to “classic” N-heterocyclic dicarbenes

    On the excitation of magnetic signals by Love waves

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    The polarization method for recognition of seismomagnetic waves against a noise background is presented. The method is applied to detection of magnetic oscillations accompanying the propagation of surface Love wave after a strong earthquake. A specific property of the Love waves is that theoretically the Tolman-Stewart effect is alone responsible for the magnetic field that penetrates into the Earth's surface. Data from the Mondy Magnetic Observatory and the Talaya Seismic Station suggest that the arrival time, duration, period,and polarization of magnetic signals conform with the idea of generation of alternating electric currents due to fluid vibrations in pores and fractures of rocks under the action of the inertial force associated with the Love wave propagation
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