304 research outputs found
A family of Nikishin systems with periodic recurrence coefficients
Suppose we have a Nikishin system of measures with the th generating
measure of the Nikishin system supported on an interval \Delta_k\subset\er
with for all . It is well known that
the corresponding staircase sequence of multiple orthogonal polynomials
satisfies a -term recurrence relation whose recurrence coefficients,
under appropriate assumptions on the generating measures, have periodic limits
of period . (The limit values depend only on the positions of the intervals
.) Taking these periodic limit values as the coefficients of a new
-term recurrence relation, we construct a canonical sequence of monic
polynomials , the so-called \emph{Chebyshev-Nikishin
polynomials}. We show that the polynomials themselves form a sequence
of multiple orthogonal polynomials with respect to some Nikishin system of
measures, with the th generating measure being absolutely continuous on
. In this way we generalize a result of the third author and Rocha
\cite{LopRoc} for the case . The proof uses the connection with block
Toeplitz matrices, and with a certain Riemann surface of genus zero. We also
obtain strong asymptotics and an exact Widom-type formula for the second kind
functions of the Nikishin system for .Comment: 30 pages, minor change
Evolution of the Greater Caucasus Basement and Formation of the Main Caucasus Thrust, Georgia
Along the northern margin of the ArabiaβEurasia collision zone in the western Greater Caucasus, the Main Caucasus Thrust (MCT) juxtaposes Paleozoic crystalline basement to the north against Mesozoic metasedimentary and volcaniclastic rocks to the south. The MCT is commonly assumed to be the trace of an active plateβboundary scale structure that accommodates ArabiaβEurasia convergence, but field data supporting this interpretation are equivocal. Here we investigate the deformation history of the rocks juxtaposed across the MCT in Georgia using field observations, microstructural analysis, UβPb and 40Ar/39Ar geochronology, and 40Ar/39Ar and (UβTh)/He thermochronology. Zircon UβPb analyses show that Greater Caucasus crystalline rocks formed in the Early Paleozoic on the margin of Gondwana. Lowβpressure/temperature amphiboliteβfacies metamorphism of these metasedimentary rocks and associated plutonism likely took place during Carboniferous accretion onto the Laurussian margin, as indicated by igneous and metamorphic zircon UβPb ages of ~330β310Β Ma. 40Ar/39Ar ages of ~190β135Β Ma from muscovite in a greenschistβfacies shear zone indicate that the MCT likely developed during Mesozoic inversion and/or rifting of the Caucasus Basin. A Mesozoic 40Ar/39Ar biotite age with release spectra indicating partial resetting and Cenozoic (<40Β Ma) apatite and zircon (UβTh)/He ages imply at least ~5β8Β km of Greater Caucasus basement exhumation since ~10Β Ma in response to ArabiaβEurasia collision. Cenozoic reactivation of the MCT may have accommodated a fraction of this exhumation. However, Cenozoic zircon (UβTh)/He ages in both the hanging wall and footwall of the MCT require partitioning a substantial component of this deformation onto structures to the south.Plain Language SummaryCollisions between continents cause deformation of the Earthβs crust and the uplift of large mountain ranges like the Himalayas. Large faults often form to accommodate this deformation and may help bring rocks once buried at great depths up to the surface of the Earth. The Greater Caucasus Mountains form the northernmost part of a zone of deformation due to the ongoing collision between the Arabian and Eurasian continents. The Main Caucasus Thrust (MCT) is a fault juxtaposing old igneous and metamorphic (crystalline) rocks against younger rocks that has often been assumed to be a major means of accommodating ArabiaβEurasia collision. This study examines the history of rocks along the MCT with a combination of field work, study of microscopic deformation in rocks, and dating of rock formation and cooling. The crystalline rocks were added to the margins of presentβday Eurasia about 330β310 million years ago, and the MCT first formed about 190β135 million years ago. The MCT is likely at most one of many structures accommodating presentβday ArabiaβEurasia collision.Key PointsAmphiboliteβfacies metamorphism and plutonism in the Greater Caucasus basement took place ~330β310Β MaThe Main Caucasus Thrust formed as a greenschistβfacies shear zone during Caucasus Basin inversion and/or rifting (~190β135Β Ma)The Main Caucasus Thrust may have helped facilitate a portion of at least 5β8Β km of basement exhumation during ArabiaβEurasia collisionPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154626/1/tect21292-sup-0002-2019TC005828-ts01.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154626/2/tect21292-sup-0006-2019TC005828-ts05.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154626/3/tect21292_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154626/4/tect21292-sup-0003-2019TC005828-ts02.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154626/5/tect21292-sup-0005-2019TC005828-ts04.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154626/6/tect21292.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154626/7/tect21292-sup-0004-2019TC005828-ts03.pd
Ladder operators and differential equations for multiple orthogonal polynomials
In this paper, we obtain the ladder operators and associated compatibility
conditions for the type I and the type II multiple orthogonal polynomials.
These ladder equations extend known results for orthogonal polynomials and can
be used to derive the differential equations satisfied by multiple orthogonal
polynomials. Our approach is based on Riemann-Hilbert problems and the
Christoffel-Darboux formula for multiple orthogonal polynomials, and the
nearest-neighbor recurrence relations. As an illustration, we give several
explicit examples involving multiple Hermite and Laguerre polynomials, and
multiple orthogonal polynomials with exponential weights and cubic potentials.Comment: 28 page
Multipoint Schur algorithm and orthogonal rational functions: convergence properties, I
Classical Schur analysis is intimately connected to the theory of orthogonal
polynomials on the circle [Simon, 2005]. We investigate here the connection
between multipoint Schur analysis and orthogonal rational functions.
Specifically, we study the convergence of the Wall rational functions via the
development of a rational analogue to the Szeg\H o theory, in the case where
the interpolation points may accumulate on the unit circle. This leads us to
generalize results from [Khrushchev,2001], [Bultheel et al., 1999], and yields
asymptotics of a novel type.Comment: a preliminary version, 39 pages; some changes in the Introduction,
Section 5 (Szeg\H o type asymptotics) is extende
ΠΠ»ΠΈΡΠ½ΠΈΠ΅ Π½ΠΎΠΊΠ΄Π°ΡΠ½Π° ΠΊΠ°Π²Π΅ΠΎΠ»ΠΈΠ½Π°-1 Π½Π° Π±Π΅Π»ΠΊΠΎΠ²ΡΠΉ ΡΠΎΡΡΠ°Π² ΡΠΊΡΡΡΠ°ΠΊΠ»Π΅ΡΠΎΡΠ½ΡΡ Π²Π΅Π·ΠΈΠΊΡΠ», ΡΠ΅ΠΊΡΠ΅ΡΠΈΡΡΠ΅ΠΌΡΡ ΠΊΠ»Π΅ΡΠΊΠ°ΠΌΠΈ Π½Π΅ΠΌΠ΅Π»ΠΊΠΎΠΊΠ»Π΅ΡΠΎΡΠ½ΠΎΠ³ΠΎ ΡΠ°ΠΊΠ° Π»Π΅Π³ΠΊΠΈΡ
Background. Recent data show evidence that lipid rafts (LR) proteins could be involved in the formation of exosomes and the sorting of proteins that make up the exosomal cargo. Such data are available for flotillins, structural and functional components of flatted rafts. The presence of the main component of caveolar rafts, caveolin-1 (Cav-1), has been shown in exosomes produced by some cancer cells; however, its possible participation in the regulation of the protein composition of exosomes has not been studied previously.Materials and methods. Knockdown of Cav-1 by transduction of a lentiviral vector expressing precursors of short hairpin ribonucleic acid to Cav-1; isolation (by ultracentrifugation) and analysis (transmission electron microscopy, nanoparticle tracking analysis) of extracellular vesicles (EVs) from non-small cell lung cancer cells (NSCLC) H1299; analysis of proteins in cells and in EVs by immunoblotting.Results. Analysis of the effect of Cav-1 expression on the composition of EV proteins associated with exosome biogenesis revealed a decrease in the level of Alix and TSG101, an increase in the level of LR proteins and the absence of changes in the level of tetraspanin CD9.Β Conclusion. The obtained data demonstrate a Cav-1-dependent changes in the composition of EVs, indicating aΒ change in the ratio of vesicles formed by the various molecular mechanisms.ΠΠ²Π΅Π΄Π΅Π½ΠΈΠ΅. ΠΠ°Π½Π½ΡΠ΅ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ ΠΏΠΎΡΠ»Π΅Π΄Π½ΠΈΡ
Π»Π΅Ρ ΡΠ²ΠΈΠ΄Π΅ΡΠ΅Π»ΡΡΡΠ²ΡΡΡ ΠΎΒ ΡΠΎΠΌ, ΡΡΠΎΒ Π±Π΅Π»ΠΊΠΈ, Π²Ρ
ΠΎΠ΄ΡΡΠΈΠ΅ Π²Β ΡΠΎΡΡΠ°Π² Π»ΠΈΠΏΠΈΠ΄Π½ΡΡ
ΡΠ°ΡΡΠΎΠ², ΠΌΠΎΠ³ΡΡ Π±ΡΡΡ Π·Π°Π΄Π΅ΠΉΡΡΠ²ΠΎΠ²Π°Π½Ρ Π²Β ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΠΈ ΡΠΊΠ·ΠΎΡΠΎΠΌ ΠΈΒ ΠΎΡΠ±ΠΎΡΠ΅ Π±Π΅Π»ΠΊΠΎΠ², Π²Ρ
ΠΎΠ΄ΡΡΠΈΡ
Π²Β ΡΠΎΡΡΠ°Π² ΡΠΊΠ·ΠΎΡΠΎΠΌΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΠΊΠ°ΡΠ³ΠΎ. Π’Π°ΠΊΠΈΠ΅ Π΄Π°Π½Π½ΡΠ΅ ΠΏΠΎΠ»ΡΡΠ΅Π½Ρ Π΄Π»ΡΒ ΡΠ»ΠΎΡΠΈΠ»Π»ΠΈΠ½ΠΎΠ², ΡΡΡΡΠΊΡΡΡΠ½ΠΎ-ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»ΡΠ½ΡΡ
ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½ΡΠΎΠ² ΠΏΠ»ΠΎΡΠΊΠΈΡ
ΡΠ°ΡΡΠΎΠ². ΠΠ»ΡΒ ΠΊΠ°Π²Π΅ΠΎΠ»ΠΈΠ½Π°-1 (Cav-1), ΠΎΡΠ½ΠΎΠ²Π½ΠΎΠ³ΠΎ ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½ΡΠ° ΠΊΠ°Π²Π΅ΠΎΠ»ΡΡΠ½ΡΡ
ΡΠ°ΡΡΠΎΠ², ΠΏΠΎΠΊΠ°Π·Π°Π½ΠΎ ΠΏΡΠΈΡΡΡΡΡΠ²ΠΈΠ΅ Π²Β ΡΠΊΠ·ΠΎΡΠΎΠΌΠ°Ρ
Π½Π΅ΠΊΠΎΡΠΎΡΡΡ
ΠΎΠΏΡΡ
ΠΎΠ»Π΅Π²ΡΡ
ΠΊΠ»Π΅ΡΠΎΠΊ, ΠΎΠ΄Π½Π°ΠΊΠΎ Π΅Π³ΠΎ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΠ΅ ΡΡΠ°ΡΡΠΈΠ΅ Π²Β ΡΠ΅Π³ΡΠ»ΡΡΠΈΠΈ Π±Π΅Π»ΠΊΠΎΠ²ΠΎΠ³ΠΎ ΡΠΎΡΡΠ°Π²Π° ΡΠΊΠ·ΠΎΡΠΎΠΌ ΡΠ°Π½Π΅Π΅ Π½Π΅Β ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π»ΠΎΡΡ.ΠΠ°ΡΠ΅ΡΠΈΠ°Π»Ρ ΠΈΒ ΠΌΠ΅ΡΠΎΠ΄Ρ. ΠΠΎΠΊΠ΄Π°ΡΠ½ Cav-1 ΠΏΡΠΎΠ²ΠΎΠ΄ΠΈΠ»ΠΈ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ ΡΡΠ°Π½ΡΠ΄ΡΠΊΡΠΈΠΈ Π»Π΅Π½ΡΠΈΠ²ΠΈΡΡΡΠ½ΠΎΠ³ΠΎ Π²Π΅ΠΊΡΠΎΡΠ°, ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΡΡΡΡΠ΅Π³ΠΎ ΠΏΡΠ΅Π΄ΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΈΠΊΠΎΠ² ΠΌΠ°Π»ΡΡ
ΡΠΏΠΈΠ»Π΅ΡΠ½ΡΡ
ΡΠΈΠ±ΠΎΠ½ΡΠΊΠ»Π΅ΠΈΠ½ΠΎΠ²ΡΡ
ΠΊΠΈΡΠ»ΠΎΡ ΠΊΒ Cav-1. ΠΠΊΡΡΡΠ°ΠΊΠ»Π΅ΡΠΎΡΠ½ΡΠ΅ Π²Π΅Π·ΠΈΠΊΡΠ»Ρ (ΠΠΠ) Π²ΡΠ΄Π΅Π»ΡΠ»ΠΈ ΠΈΠ·Β ΠΊΠ»Π΅ΡΠΎΠΊ Π»ΠΈΠ½ΠΈΠΈ Π1299 Π½Π΅ΠΌΠ΅Π»ΠΊΠΎΠΊΠ»Π΅ΡΠΎΡΠ½ΠΎΠ³ΠΎ ΡΠ°ΠΊΠ° Π»Π΅Π³ΠΊΠΈΡ
ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ Π΄ΠΈΡΡΠ΅ΡΠ΅Π½ΡΠΈΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΠ»ΡΡΡΠ°ΡΠ΅Π½ΡΡΠΈΡΡΠ³ΠΈΡΠΎΠ²Π°Π½ΠΈΡ. ΠΡΠ΅ΠΏΠ°ΡΠ°ΡΡ ΠΠΠ Π²Π΅ΡΠΈΡΠΈΡΠΈΡΠΎΠ²Π°Π»ΠΈ ΡΒ ΠΏΠΎΠΌΠΎΡΡΡ ΡΡΠ°Π½ΡΠΌΠΈΡΡΠΈΠΎΠ½Π½ΠΎΠΉ ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΠΎΠΉ ΠΌΠΈΠΊΡΠΎΡΠΊΠΎΠΏΠΈΠΈ (Π°Π½Π°Π»ΠΈΠ· ΡΠ°Π·ΠΌΠ΅ΡΠ° ΠΈΒ ΠΌΠΎΡΡΠΎΠ»ΠΎΠ³ΠΈΠΈ) ΠΈΒ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ Π°Π½Π°Π»ΠΈΠ·Π° ΡΡΠ°Π΅ΠΊΡΠΎΡΠΈΠΉ Π΄Π²ΠΈΠΆΠ΅Π½ΠΈΡ Π½Π°Π½ΠΎΡΠ°ΡΡΠΈΡ (ΡΡΠ΅Π΄Π½Π΅ΡΠ°Π·ΠΌΠ΅ΡΠ½ΠΎΠ΅ ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅ ΠΈΒ ΠΊΠΎΠ½ΡΠ΅Π½ΡΡΠ°ΡΠΈΡ). ΠΠ»ΡΒ Π°Π½Π°Π»ΠΈΠ·Π° ΡΠΊΠ·ΠΎΡΠΎΠΌΠ°Π»ΡΠ½ΡΡ
ΠΌΠ°ΡΠΊΠ΅ΡΠΎΠ² ΠΈΒ Cav-1 Π²Β ΠΊΠ»Π΅ΡΠΊΠ°Ρ
ΠΈΒ ΠΠΠ ΠΏΡΠΈΠΌΠ΅Π½ΡΠ»ΠΈ ΠΌΠ΅ΡΠΎΠ΄ ΠΈΠΌΠΌΡΠ½ΠΎΠ±Π»ΠΎΡΡΠΈΠ½Π³Π°.Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ. ΠΠ½Π°Π»ΠΈΠ· Π²Π»ΠΈΡΠ½ΠΈΡ ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΠΈ Cav-1 Π½Π°Β ΡΠΎΡΡΠ°Π² Π±Π΅Π»ΠΊΠΎΠ² ΠΠΠ, Π°ΡΡΠΎΡΠΈΠΈΡΠΎΠ²Π°Π½Π½ΡΡ
ΡΒ Π±ΠΈΠΎΠ³Π΅Π½Π΅Π·ΠΎΠΌ ΡΠΊΠ·ΠΎΡΠΎΠΌ, Π²ΡΡΠ²ΠΈΠ» ΡΠ½ΠΈΠΆΠ΅Π½ΠΈΠ΅ ΡΡΠΎΠ²Π½Ρ Alix ΠΈΒ TSG101, ΠΏΠΎΠ²ΡΡΠ΅Π½ΠΈΠ΅ ΡΡΠΎΠ²Π½Ρ Π±Π΅Π»ΠΊΠΎΠ² Π»ΠΈΠΏΠΈΠ΄Π½ΡΡ
ΡΠ°ΡΡΠΎΠ² ΠΈΒ ΠΎΡΡΡΡΡΡΠ²ΠΈΠ΅ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠΉ ΡΡΠΎΠ²Π½Ρ ΡΠ΅ΡΡΠ°ΡΠΏΠ°Π½ΠΈΠ½Π° CD9.ΠΠ°ΠΊΠ»ΡΡΠ΅Π½ΠΈΠ΅. ΠΠΎΠ»ΡΡΠ΅Π½Π½ΡΠ΅ Π΄Π°Π½Π½ΡΠ΅ Π΄Π΅ΠΌΠΎΠ½ΡΡΡΠΈΡΡΡΡ Cav-1-Π·Π°Π²ΠΈΡΠΈΠΌΠΎΠ΅ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠ΅ ΡΠΎΡΡΠ°Π²Π° ΠΠΠ, ΡΠ²ΠΈΠ΄Π΅ΡΠ΅Π»ΡΡΡΠ²ΡΡΡΠ΅Π΅ ΠΎΠ± ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠΈ ΡΠΎΠΎΡΠ½ΠΎΡΠ΅Π½ΠΈΡ Π²Π΅Π·ΠΈΠΊΡΠ», ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½Π½ΡΡ
Ρ ΠΏΠΎΠΌΠΎΡΡΡ ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
ΠΌΠΎΠ»Π΅ΠΊΡΠ»ΡΡΠ½ΡΡ
ΠΌΠ΅Ρ
Π°Π½ΠΈΠ·ΠΌΠΎΠ².
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