196 research outputs found

    On regularization of Mellin PDO's with slowly oscillating symbols of limited smoothness

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    We study Mellin pseudodifferential operators (shortly, Mellin PDO's) with symbols in the algebra E~(R+,V(R))\widetilde{\mathcal{E}}(\mathbb{R}_+,V(\mathbb{R})) of slowly oscillating functions of limited smoothness introduced in \cite{K09}. We show that if aE~(R+,V(R))\mathfrak{a}\in\widetilde{\mathcal{E}}(\mathbb{R}_+,V(\mathbb{R})) does not degenerate on the "boundary" of R+×R\mathbb{R}_+\times\mathbb{R} in a certain sense, then the Mellin PDO Op(a){\rm Op}(\mathfrak{a}) is Fredholm on the space LpL^p for p(1,)p\in(1,\infty) and each its regularizer is of the form Op(b)+K{\rm Op}(\mathfrak{b})+K where KK is a compact operator on LpL^p and b\mathfrak{b} is a certain explicitly constructed function in the same algebra E~(R+,V(R))\widetilde{\mathcal{E}}(\mathbb{R}_+,V(\mathbb{R})) such that b=1/a\mathfrak{b}=1/\mathfrak{a} on the "boundary" of R+×R\mathbb{R}_+\times\mathbb{R}. This result complements a known Fredholm criterion from \cite{K09} for Mellin PDO's with symbols in the closure of E~(R+,V(R))\widetilde{\mathcal{E}}(\mathbb{R}_+,V(\mathbb{R})).Comment: 20 page

    Semi-Fredholmness of weighted singular integral operators with shifts and slowly oscillating data

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    Let α,β\alpha,\beta be orientation-preserving homeomorphisms of [0,][0,\infty] onto itself, which have only two fixed points at 00 and \infty, and whose restrictions to R+=(0,)\mathbb{R}_+=(0,\infty) are diffeomorphisms, and let Uα,UβU_\alpha,U_\beta be the corresponding isometric shift operators on the space Lp(R+)L^p(\mathbb{R}_+) given by Uμf=(μ)1/p(fμ)U_\mu f=(\mu')^{1/p}(f\circ\mu) for μ{α,β}\mu\in\{\alpha,\beta\}. We prove sufficient conditions for the right and left Fredholmness on Lp(R+)L^p(\mathbb{R}_+) of singular integral operators of the form A+Pγ++APγA_+P_\gamma^++A_-P_\gamma^-, where Pγ±=(I±Sγ)/2P_\gamma^\pm=(I\pm S_\gamma)/2, SγS_\gamma is a weighted Cauchy singular integral operator, A+=kZakUαkA_+=\sum_{k\in\mathbb{Z}}a_kU_\alpha^k and A=kZbkUβkA_-=\sum_{k\in\mathbb{Z}}b_kU_\beta^k are operators in the Wiener algebras of functional operators with shifts. We assume that the coefficients ak,bka_k,b_k for kZk\in\mathbb{Z} and the derivatives of the shifts α,β\alpha',\beta' are bounded continuous functions on R+\mathbb{R}_+ which may have slowly oscillating discontinuities at 00 and \infty.Comment: Accepted for publication in the Proceedings of WOAT 2016 held in Lisbon in July of 2016, which will be published in the special volume "Operator Theory, Operator Algebras, and Matrix Theory" of OT series (Birkh\"auser

    The influence of age diversity practices on workers’ well-being and intention to leave:The role of the relational psychological contract

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    O envelhecimento da população mundial acarreta inúmeros desafios para as organizações, entre os quais a retenção de uma força de trabalho cada vez mais diversa em termos de idade. Com base nas teorias do contrato psicológico e da troca social, este estudo examina o efeito das práticas de diversidade etária no bem-estar subjetivo e na intenção de saída dos trabalhadores via contrato psicológico relacional. Uma amostra de 257 trabalhadores portugueses respondeu a um questionário. A análise de equações estruturais foi aplicada para testar o modelo de mediação. Os resultados mostraram que a existência de práticas de diversidade etária contribui para o desenvolvimento de um contrato psicológico do tipo relacional o que, por sua vez, leva a maiores níveis de bem-estar e a menores intenções de saída da organização. As implicações teóricas e práticas dos resultados são discutidas.info:eu-repo/semantics/publishedVersio

    Amphipoda (Crustacea) Associados a “Bostrychietum” em uma Área de Manguezal na Região Norte do Estado de São Paulo

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    O manguezal é um sistema ecológico tropical que se restringe a estreitas faixas costeiras, apresentando condições propícias para alimentação, proteção e reprodução de muitas espécies de animais. Nos manguezais ocorrem importantes associações de macroalgas aderidas em pneumatóforos, rizóforos e troncos das árvores dos gêneros Avicennia L., Rhizophora L. e Laguncularia Gaertn denominadas como “Bostrychietum”. Essas associações incluem cianobactérias e clorofíceas, contudo há imensa dominância de rodofïceas, mais precisamente dos gêneros Bostrychia Mont., Caloglossa (Harv.) G. Martens e Catenella Grev. Os Amphipoda são muito comuns em ambientes de manguezal ao redor do mundo, no entanto não há nenhum estudo faunístico abrangente sobre este grupo para manguezais brasileiros. A área de estudo é uma região de manguezal localizada no Município de São Vicente, Baixada Santista, região norte do estado de São Paulo. A comunidade de “Bostrychietum” é coletada por meio de raspagem dos substratos (pneumatóforos, rizóforos e troncos). Os anfípodes são anestesiados por meio de submerssão em etanol 5-10%. Posteriormente, os anfípodes são triados em laboratório, fixados em etanol 70% e identificados com base em literatura especializada. As amostras de “Bostrychietum” foram depositadas na coleção de algas da Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), Campus do Litoral Paulista. Todo o material de Amphipoda está conservado em etanol 70% na coleção do Laboratório de Zoologia do UniFOA. Após a realização do estudo todo o material será depositado em coleções zoológicas de referência. Este projeto está em fase intermediária e parte das amostras já foi analisada. Uma lista preliminar da fauna Amphipoda identificada será apresentada

    Enumeration and phenotypical analysis of distinct dendritic cell subsets in psoriatic arthritis and rheumatoid arthritis

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    Dendritic cells (DCs) comprise heterogeneous subsets of professional antigen-presenting cells, linking innate and adaptive immunity. Analysis of DC subsets has been hampered by a lack of specific DC markers and reliable quantitation assays. We characterised the immunophenotype and functional characteristics of psoriatic arthritis (PsA)-derived and rheumatoid arthritis (RA)-derived myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) to evaluate their potential role in arthritis. Circulating peripheral blood (PB) pDC numbers were significantly reduced in PsA patients (P = 0.0098) and RA patients (P = 0.0194), and mDCs were significantly reduced in RA patients (P = 0.0086) compared with healthy controls. The number of circulating mDCs in RA PB was significantly inversely correlated to C-reactive protein (P = 0.021). The phenotype of both DC subsets in PsA PB and RA PB was immature as compared with healthy controls. Moreover, CD62L expression was significantly decreased on both mDCs (PsA, P = 0.0122; RA, P = 0.0371) and pDCs (PsA, P = 0.0373; RA, P = 0.0367) in PB. Both mDCs and pDCs were present in PsA synovial fluid (SF) and RA SF, with the mDC:pDC ratio significantly exceeding that in matched PB (PsA SF, P = 0.0453; RA SF, P = 0.0082). pDCs isolated from RA SF and PsA SF displayed an immature phenotype comparable with PB pDCs. RA and PsA SF mDCs, however, displayed a more mature phenotype (increased expression of CD80, CD83 and CD86) compared with PB mDCs. Functional analysis revealed that both SF DC subsets matured following toll-like receptor stimulation. pDCs from PB and SF produced interferon alpha and tumour necrosis factor alpha on TLR9 stimulation, but only SF pDCs produced IL-10. Similarly, mDCs from PB and SF produced similar tumour necrosis factor alpha levels to TLR2 agonism, whereas SF mDCs produced more IL-10 than PB controls. Circulating DC subset numbers are reduced in RA PB and PsA PB with reduced CD62L expression. Maturation is incomplete in the inflamed synovial compartment. Immature DCs in SF may contribute to the perpetuation of inflammation via sampling of the inflamed synovial environment, and in situ presentation of arthritogenic antigen

    Association of the mtDNA m.4171C>A/MT-ND1 mutation with both optic neuropathy and bilateral brainstem lesions

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    Background: An increasing number of mitochondrial DNA (mtDNA) mutations, mainly in complex I genes, have been associated with variably overlapping phenotypes of Leber’s hereditary optic neuropathy (LHON), mitochondrial encephalomyopathy with stroke-like episodes (MELAS) and Leigh syndrome (LS). We here describe the first case in which the m.4171C>A/MT-ND1 mutation, previously reported only in association with LHON, leads also to a Leigh-like phenotype. Case presentation: A 16-year-old male suffered subacute visual loss and recurrent vomiting and vertigo associated with bilateral brainstem lesions affecting the vestibular nuclei. His mother and one sister also presented subacute visual loss compatible with LHON. Sequencing of the entire mtDNA revealed the homoplasmic m.4171C>A/MT-ND1 mutation, previously associated with pure LHON, on a haplogroup H background. Three additional non-synonymous homoplasmic transitions affecting ND2 (m.4705T>C/MT-ND2 and m.5263C>T/MT-ND2) and ND6 (m.14180T>C/MT-ND6) subunits, well recognized as polymorphisms in other mtDNA haplogroups but never found on the haplogroup H background, were also present. Conclusion: This case widens the phenotypic expression of the rare m.4171C>A/MT-ND1 LHON mutation, which may also lead to Leigh-like brainstem lesions, and indicates that the co-occurrence of other ND non-synonymous variants, found outside of their usual mtDNA backgrounds, may have increased the pathogenic potential of the primary LHON mutation

    Three Wide-Separation L dwarf Companions from the Two Micron All Sky Survey: Gl 337C, Gl 618.1B, and HD 89744B

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    We present two confirmed wide separation L-dwarf common proper motion companions to nearby stars and one candidate identified from the Two Micron All Sky Survey. Spectral types from optical spectroscopy are L0 V, L2.5 V, and L8 V. Near-infrared low resolution spectra of the companions are provided as well as a grid of known objects spanning M6 V -- T dwarfs to support spectral type assignment for these and future L-dwarfs in the z'JHK bands. Using published measurements, we estimate ages of the companions from physical properties of the primaries. These crude ages allow us to estimate companion masses using theoretical low-mass star and brown dwarf evolutionary models. The new L-dwarfs in this paper bring the number of known wide-binary (Separation >= 100 AU) L-dwarf companions of nearby stars to nine. One of the L-dwarfs is a wide separation companion to the F7 IV-V + extrasolar planet system HD89744Ab.Comment: 20 pages including 6 tables and 4 figures, AJ, in pres
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