1,137 research outputs found

    The distribution of estimates of parameters of multidimensional stationary AR processes

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    AbstractIt is shown that the suitably normalized maximum likelihood estimates of the parameters of periodical type of some multidimensional stationary AR processes have exactly normal distribution. This provides a generalization of the well-known behaviour of the estimate of period of a complex 1-dimensional AR process (see [1–6])

    Asymptotic boundary forms for tight Gabor frames and lattice localization domains

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    We consider Gabor localization operators Gϕ,ΩG_{\phi,\Omega} defined by two parameters, the generating function ϕ\phi of a tight Gabor frame {ϕλ}λΛ\{\phi_\lambda\}_{\lambda \in \Lambda}, parametrized by the elements of a given lattice ΛR2\Lambda \subset \Bbb{R}^2, i.e. a discrete cocompact subgroup of R2\Bbb{R}^2, and a lattice localization domain ΩR2\Omega \subset \Bbb{R}^2 with its boundary consisting of line segments connecting points of Λ\Lambda. We find an explicit formula for the boundary form BF(ϕ,Ω)=AΛlimRPF(Gϕ,RΩ)RBF(\phi,\Omega)=\text{A}_\Lambda \lim_{R\rightarrow \infty}\frac{PF(G_{\phi,R\Omega})}{R}, the normalized limit of the projection functional PF(Gϕ,Ω)=i=0λi(Gϕ,Ω)(1λi(Gϕ,Ω))PF(G_{\phi,\Omega})=\sum_{i=0}^{\infty}\lambda_i(G_{\phi,\Omega})(1-\lambda_i(G_{\phi,\Omega})), where λi(Gϕ,Ω)\lambda_i(G_{\phi,\Omega}) are the eigenvalues of the localization operators Gϕ,ΩG_{\phi,\Omega} applied to dilated domains RΩR\Omega, RR is an integer and AΛ\text{A}_\Lambda is the area of the fundamental domain of the lattice Λ\Lambda.Comment: 35 page

    Modeling Solar Lyman Alpha Irradiance

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    Solar Lyman alpha irradiance is estimated from various solar indices using linear regression analyses. Models developed with multiple linear regression analysis, including daily values and 81-day running means of solar indices, predict reasonably well both the short- and long-term variations observed in Lyman alpha. It is shown that the full disk equivalent width of the He line at 1083 nm offers the best proxy for Lyman alpha, and that the total irradiance corrected for sunspot effect also has a high correlation with Lyman alpha

    Pitfalls during biomechanical testing — Evaluation of different fixation methods for measuring tendons endurance properties

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    The goal of the study was to find a proper technique to fix tendon grafts into an INSTRON loading machine. From 8 human cadavers, 40 grafts were collected. We removed the bone-patella tendon-bone grafts, the semitendinosus and gracilis tendons, the quadriceps tendon-bone grafts, the Achilles tendons, and the peroneus longus tendons from each lower extremity. We tested the tendon grafts with five different types of fixation devices: surgical thread (Premicron 3), general mounting clamp, wire mesh, cement fixation, and a modified clamp for an INSTRON loading machine. The mean failure load in case of surgical thread fixation was (381N ± 26N). The results with the general clamp were (527N ± 45N). The wire meshes were more promising (750N ± 21N), but did not reach the outcomes we desired. Easy slippages of the ends of the tendons from the cement encasements were observed (253N ± 18N). We then began to use Shi’s clamp that could produce 977N ± 416N peak force. We combined Shi’s clamp with freezing of the graft and the rupture of the tendon itself demonstrated an average force of 2198 N ± 773N. We determined that our modified frozen clamp fixed the specimens against high tensile forces

    Humán albuminnal kezelt strukturális proximális tibialis allograft alkalmazása kiterjedt térdízületi periprotetikus csonthiány esetén és a késői szövődmény elhárítása

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    A szerzők 74 éves beteg kórtörténetét ismertetik, akinél kiterjedt szegmentális térdízületi periprotetikus csontvesztés műtéti kezelése során strukturális proximalis tibialis allograftot alkalmaztak és beszámolnak a műtét után kialakult késői szövődmény ellátásáról. Kiemelik, hogy az allograftokkal történő csontpótlás fiziológiás eljárás, amely lehetőséget ad stabil implantátum rögzítésére, lágyrész-rekonstrukcióra, kiterjedt csontvesztés pótlására, és a beavatkozás költsége is kevesebb. A liofilizált allograft albuminnal történő kezelése bizonyítottan javítja azt a képességet, hogy a csontvelő-eredetű mesenchymalis őssejtek az allograft felszínén megtapadjanak, azon proliferáljanak, valamint annak pórusaiba is beterjedjenek és ezáltal a graft mélyebb rétegeibe is eljussanak. Kimutatható osteoblast tevékenység alakult ki a graft felszínén és a belsejében is. Orv. Hetil., 2015, 156(2), 67–70

    Numerical study of SU(2) Yang-Mills theory with gluinos

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    We report on a numerical investigation of the SU(2) gauge theory with gluinos. The low-lying spectrum in bosonic and fermionic channels is determined. Improvements of the multi-bosonic algorithm are discussed.Comment: latex, 3 pages, 4 figures; Poster presented by K. Spanderen at LATTICE9

    Optimal General Matchings

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    Given a graph G=(V,E)G=(V,E) and for each vertex vVv \in V a subset B(v)B(v) of the set {0,1,,dG(v)}\{0,1,\ldots, d_G(v)\}, where dG(v)d_G(v) denotes the degree of vertex vv in the graph GG, a BB-factor of GG is any set FEF \subseteq E such that dF(v)B(v)d_F(v) \in B(v) for each vertex vv, where dF(v)d_F(v) denotes the number of edges of FF incident to vv. The general factor problem asks the existence of a BB-factor in a given graph. A set B(v)B(v) is said to have a {\em gap of length} pp if there exists a natural number kB(v)k \in B(v) such that k+1,,k+pB(v)k+1, \ldots, k+p \notin B(v) and k+p+1B(v)k+p+1 \in B(v). Without any restrictions the general factor problem is NP-complete. However, if no set B(v)B(v) contains a gap of length greater than 11, then the problem can be solved in polynomial time and Cornuejols \cite{Cor} presented an algorithm for finding a BB-factor, if it exists. In this paper we consider a weighted version of the general factor problem, in which each edge has a nonnegative weight and we are interested in finding a BB-factor of maximum (or minimum) weight. In particular, this version comprises the minimum/maximum cardinality variant of the general factor problem, where we want to find a BB-factor having a minimum/maximum number of edges. We present an algorithm for the maximum/minimum weight BB-factor for the case when no set B(v)B(v) contains a gap of length greater than 11. This also yields the first polynomial time algorithm for the maximum/minimum cardinality BB-factor for this case

    Antibody-mediated inhibition of syndecan-4 dimerisation reduces interleukin (IL)-1 receptor trafficking and signalling.

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    OBJECTIVE: Syndecan-4 (sdc4) is a cell-anchored proteoglycan that consists of a transmembrane core protein and glucosaminoglycan (GAG) side chains. Binding of soluble factors to the GAG chains of sdc4 may result in the dimerisation of sdc4 and the initiation of downstream signalling cascades. However, the question of how sdc4 dimerisation and signalling affects the response of cells to inflammatory stimuli is unknown. METHODS: Sdc4 immunostaining was performed on rheumatoid arthritis (RA) tissue sections. Interleukin (IL)-1 induced extracellular signal-regulated kinases (ERK) phosphorylation and matrix metalloproteinase-3 production was investigated. Il-1 binding to sdc4 was investigated using immunoprecipitation. IL-1 receptor (IL1R1) staining on wild-type, sdc4 and IL1R1 knockout fibroblasts was performed in fluorescence-activated cell sorting analyses. A blocking sdc4 antibody was used to investigate sdc4 dimerisation, IL1R1 expression and the histological paw destruction in the human tumour necrosis factor-alpha transgenic mouse. RESULTS: We show that in fibroblasts, the loss of sdc4 or the antibody-mediated inhibition of sdc4 dimerisation reduces the cell surface expression of the IL-1R and regulates the sensitivity of fibroblasts to IL-1. We demonstrate that IL-1 directly binds to sdc4 and in an IL-1R-independent manner leads to its dimerisation. IL-1-induced dimerisation of sdc4 regulates caveolin vesicle-mediated trafficking of the IL1R1, which in turn determines the responsiveness to IL-1. Administration of antibodies (Ab) against the dimerisation domain of sdc4, thus, strongly reduces the expression IL1R1 on arthritic fibroblasts both in vitro and an animal model of human RA. CONCLUSION: Collectively, our data suggest that Ab that specifically inhibit sdc4 dimerisation may support anti-IL-1 strategies in diseases such as inflammatory arthritis
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