1,721,029 research outputs found
Micro-Raman mapping of the strain field in GaAsN/GaAsN:H planar heterostructures: A brief review and recent evolution
No full textRaman scattering is an effective tool for the investigation of the strain state of crystalline solids. In this brief review, we show how the analysis of the GaAs-like longitudinal optical phonon frequency allowed to map the strain behavior across interfaces in planar heterostructures consisting of GaAsN wires embedded in GaAsN:H matrices. Moreover, we recently showed how the evolution of the longitudinal optical frequency with increasing H dose strongly depends on polarization geometry. In a specific geometry, we observed a relaxation of the GaAs selection rules. We also present new results which demonstrate how laser irradiation intensity-even at low levels-may affect the line shape of the GaAs-like spectral features in GaAsN hydrogenated materials
Characterization of waveguides obtained by proton exchange on a LiNbO3 substrate
No full textWaveguides obtained by proton exchange in LiNbO3 were characterized by Secondary Ion Mass Spectrometry and m-lines technique. Additional micro-Raman investigations evidenced marked changes in the spectra of the waveguide with respect to the substrate. This suggests that micro-Raman spectroscopy may constitute a direct non-destructive method to determine the depth of the exchanged layer, with a limit which is set by the diffraction-limited spot size
Assignment of the Equus caballus interleukin 8 gene (IL8) to chromosome 3q14.2-> q14.3 by in situ hybridization
No full text© 2006 S. Karger AG, BaselNergadze, S.G. ; Magnani, E. ; Attolini, C. ; Bertoni, L. ; Adelson, D.L. ; Cappelli, K. ; Verini Supplizi, A. ; Giulotto, E
The Unique DNA Sequences Underlying Equine Centromeres
No full textCentromeres are highly distinctive genetic loci whose function is specified largely by epigenetic mechanisms. Understanding the role of DNA sequences in centromere function has been a daunting task due to the highly repetitive nature of centromeres in animal chromosomes. The discovery of a centromere devoid of satellite DNA in the domestic horse consolidated observations on the epigenetic nature of centromere identity, showing that entirely natural chromosomes could function without satellite DNA cues. Horses belong to the genus Equus which exhibits a very high degree of evolutionary plasticity in centromere position and DNA sequence composition. Examination of horses has revealed that the position of the satellite-free centromere is variable among individuals. Analysis of centromere location and composition in other Equus species, including domestic donkey and zebras, confirms that the satellite-less configuration of centromeres is common in this group which has undergone particularly rapid karyotype evolution. These features have established the equids as a new mammalian system in which to investigate the molecular organization, dynamics and evolutionary behaviour of centromeres
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Novel cathelicidins in horse leukocytes
No full textCathelicidins are precursors of defense peptides of the
innate immunity and are widespread in mammals. Their structure
comprises a conserved prepropiece and an antimicrobial domain
that is structurally varied both intra- and inter-species. We
investigated the complexity of the cathelicidin family in horse by
a reverse transcription-PCR-based cloning strategy of myeloid
mRNA and by Southern and Western analyses. Three novel
cathelicidin sequences were deduced from bone marrow mRNA
and designated equine cathelicidins eCATH-1, eCATH-2 and
eCATH-3. Putative antimicrobial domains of 26, 27 and
40 residues with no significant sequence homology to other
peptides were inferred at the C-terminus of the sequences.
Southern analysis of genomic DNA using a probe based on the
cathelicidin-conserved propiece revealed a polymorphic DNA
region with several hybridization-positive fragments and suggested
the presence of additional genes. A null eCATH-1 allele
was also demonstrated with a frequency of 0.71 in the horse
population analyzed and low amounts of eCATH-1-specific
mRNA were found in myeloid cells of gene-positive animals. A
Western analysis using antibodies to synthetic eCATH peptides
revealed the presence of eCATH-2 and eCATH-3 propeptides,
but not of eCATH-1-related polypeptides, in horse neutrophil
granules and in the secretions of phorbol myristate acetatestimulated
neutrophils. These results thus suggest that eCATH-2
and eCATH-3 are functional genes, whereas eCATH-1 is unable
to encode a polypeptide
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