1,721,130 research outputs found
Bayesian Model Selection for Beta Autoregressive Processes
No full textWe deal with Bayesian model selection for beta autoregressive processes. We discuss the choice of parameter and model priors with possible parameter restrictions and suggest a Reversible Jump Markov-Chain Monte Carlo (RJMCMC) procedure based on a Metropolis-Hastings within Gibbs algorithm.We deal with Bayesian model selection for beta autoregressive processes. We discuss the choice of parameter and model priors with possible parameter restrictions and suggest a Reversible Jump Markov-Chain Monte Carlo (RJMCMC) procedure based on a Metropolis-Hastings within Gibbs algorithm
Approximate Bayesian conditional copulas
Full text linkCopula models are flexible tools to represent complex structures of dependence for multivariate random variables. According to Sklar's theorem, any multidimensional absolutely continuous distribution function can be uniquely represented as a copula, i.e. a joint cumulative distribution function on the unit hypercube with uniform marginals, which captures the dependence structure among the vector components. In real data applications, the interest of the analyses often lies on specific functionals of the dependence, which quantify aspects of it in a few numerical values. A broad literature exists on such functionals, however extensions to include covariates are still limited. This is mainly due to the lack of unbiased estimators of the conditional copula, especially when one does not have enough information to select the copula model. Several Bayesian methods to approximate the posterior distribution of functionals of the dependence varying according covariates are presented and compared; the main advantage of the investigated methods is that they use nonparametric models, avoiding the selection of the copula, which is usually a delicate aspect of copula modelling. These methods are compared in simulation studies and in two realistic applications, from civil engineering and astrophysics. (C) 2022 Elsevier B.V. All rights reserved
Isolation of a new class of cysteine-glycine-proline rich beta-proteins (beta-keratins) and their expression in snake epidermis
No full textMolecular analysis has allowed the identification in the snake E. guttata of cysteine-rich beta-proteins. These proteins are present in the beta-layer of the epidermis
Expression of beta-keratin mRNAs and proline uptake in epidermal cells of growing scales and pad lamellae of gecko liz
No full textGene expression in regenerating and scarring tails of lizard evidences three main key genes (wnt2b, egfl6, and arhgap28) activated during the regulated process of tail regeneration
No full textWe have analyzed the expression of key genes orchestrating tail regeneration in lizard under normal and scarring conditions after cauterization. At 1-day post-cauterization (1 dpc), the injured blastema contains degenerating epithelial and mesenchymal cells, numerous mast cells, and immune cells. At 3 and 7 dpc, a stratified wound epidermis is forming while fibrocytes give rise to a scarring connective tissue. Oncogenes such as wnt2b, egfl6, wnt6, and mycn and the tumor suppressor arhgap28 are much more expressed than other oncogenes (hmga2, rhov, fgf8, fgfr4, tert, shh) and tumor suppressors (apcdd1, p63, rb, fat2, bcl11b) in the normal blastema and at 7 dpc. Blastemas at 3 dpc feature the lowest upregulation of most genes, likely derived from damage after cauterization. Immunomodulator genes nfatc4 and lef1 are more expressed at 7 dpc than in normal blastema and 3 dpc suggesting the induction of immune response favoring scarring. Balanced over-expression of oncogenes, tumor suppressor genes, and immune modulator genes determines regulation of cell proliferation (anti-oncogenic), of movement (anti-metastatic), and immunosuppression in the normal blastema. Significant higher expression of oncogenes wnt2b and egfl6 in normal blastema and higher expression of the tumor suppressor arhgap28 in the 7 dpc blastema indicate that they are among the key/master genes that determine the regulated regeneration of the tail
Distribution of specific keratin associated beta-proteins (beta-keratins) in the epidermis of the lizard Anolis carolinensis helps to clarify the process of cornification in lepidosaurians
No full textThe present western blotting and immunocytochemical study analyzse the localization in different scales and skin appendages of specific keratin-associated beta proteins. It is concluded that glycine-rich beta proteions are typical for the beta-layer while cysteine-glycine beta proteins are more ubiquitarious
Ultrastructural localization of hair keratin homologs in the claw of the lizard Anolis carolinensis
No full textThe ultrastructural localization of two hair-like keratins has been done fot the claw of the lizard A. carolinensis. It has shown that the transitional and the corneous layers contain both hard keratins and keratin associated beta-proteins
Sex and Brain: The Role of Sex Chromosomes and Hormones in Brain Development and Parkinson's Disease
Full text linkIsolation of a mRNA encoding a glycine-proline-rich beta-keratin expressed in the regenerating epidermis of lizard
No full textDuring scale regeneration in lizard tail, an active differentiation of beta-keratin synthesizing cells occurs. The cDNA and amino acid sequence of a lizard beta-keratin has been obtained from mRNA isolated from regenerating epidermis. Degenerate oligonucleotides, selected from the translated amino acid sequence of a lizard claw protein, were used to amplify a specific lizard keratin cDNA fragment from the mRNA after reverse transcription with poly dT primer and subsequent polymerase chain reaction (3'-rapid amplification of cDNA ends analysis, 3'-RACE). The new sequence was used to design specific primers to obtain the complete cDNA sequence by 5'-RACE. The 835-nucleotide cDNA sequence encodes a glycine-proline-rich protein containing 163 amino acids with a molecular mass of 15.5 kDa; 4.3% of its amino acids is represented by cysteine, 4.9% by tyrosine, 8.0% by proline, and 29.4% by glycine. Tyrosine is linked to glycine, and proline is present mainly in the central region of the protein. Repeated glycine-glycine-X and glycine-X amino acid sequences are localized near the N-amino and C-terminal regions. The protein has the central amino acid region similar to that of claw-feather, whereas the head and tail regions are similar to glycine-tyrosine-rich proteins of mammalian hairs. In situ hybridization analysis at light and electron microscope reveals that the corresponding mRNA is expressed in cells of the differentiating beta-layers of the regenerating scales. The synthesis of beta-keratin from its mRNA occurs among ribosomes or is associated with the surface of beta-keratin filaments
Bioinformatic and molecular characterization of cathelicidin-like peptides isolated from the green lizard Anolis carolinensis. Ital
No full textThe high resistance to infections in lizards indicates that these reptiles possess active processes of innate immunity including
the production of antimicrobial peptides. The present bioinformatic and molecular study on the lizard Anolis carolinensis
reports the presence of three cathelicidin-like-genes and their deduced peptides. These antimicrobial peptides have been
named as AcCATH-1, −2 and −3, and represent the first cathelicidins so far identified in lizards. These peptides contain
the characteristic cathelin-like domain identified in cathelicidins present in other species of vertebrates. The expression
of the three genes in different tissues of healthy lizards has been determined by semi-quantitative reverse transcription
polymerase chain reaction (RT-PCR). Lizard cathelicidin genes show a genome organization similar to that of mammals
but with a number of exons ranging from three to five. The gene coding for AcCATH-3 is missing the third exon, like two
cathelicidins found in fish. Gene expression analysis suggests the presence of alternative splicing mechanisms. Cathelicidins
and beta-defensins recently found in this lizard suggest that these peptides elicit effective protection against infections in
these reptiles
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