1,721,039 research outputs found
A safe fix for alcohol-derived DNA damage
No full textA by-product of alcohol metabolism can damage the genome by crosslinking opposing DNA strands. The discovery of a safe mechanism that reverses such damage might open up avenues of research for drug discovery.A previously unknown mechanism for repairing DNA interstrand crosslinks
Summary of SSR types and frequency in <i>Chamelea gallina</i> transcriptome.
No full text<p>Summary of SSR types and frequency in <i>Chamelea gallina</i> transcriptome.</p
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
Cantor Dielectric Filters in Rectangular Waveguides
No full textA triadic Cantor fractal multi-layer is a stack of two different dielectric materials whose thicknesses are determined according to the triadic Cantor fractal scheme. When inserted in a rectangular waveguide, the spectral response of a triadic Cantor multi-layer can be tailored to feature a narrow single transmission peak in the waveguide single-mode frequency range, with a low insertion loss and a high rejection level of forbidden frequencies. The experimental characterization of alumina-polystyrene and plexiglass-polystyrene Cantor multi-layers inserted in a WR90 waveguide (Hewlett-Packard, USA) matches thoroughly with the results of the theoretical modeling and demonstrates that triadic Cantor multi-layers can be used to realize feasible narrow-band microwave filters
Omnidirectional bandgap in Cantor dielectric multilayers
No full textAnalysis of the transmission spectrum of Cantor dielectric multilayers for obliquely incident plane wave
shows that the main bandgap shifts towards higher frequencies, substantially retaining its shape, as the
incidence angle increases for both s- and p-polarization of the impinging wave. For suitable refractive
index values of the two constituent materials a range of frequencies can be found where transmission
of the incident wave is almost completely forbidden at any angle of incidence. This omnidirectional bandgap
can be found also for lossy media. In this case the stop-band widens as the tangent loss increases,
while the depth of the stop-band does not change significantly. Comparison with the periodic quarterwave
stack shows that the Cantor multilayer exhibits a narrower omnidirectional bandgap with transmissivity
values that are about one order of magnitude lower
Field localization inside a lossy dielectric slab by means of cantor dielectric multilayers
No full textA Cantor multilayer is an electromagnetic band-gap structure consisting of a stack of alternating
high-/low-permittivity dielectric layers whose optical lengths follow the fractal Cantor construction.
The deepest stop band is bounded by two narrow transmission peaks centered at frequencies where
a strong field localization occurs inside the structure. This phenomenon also occurs if a lossy
dielectric slab is inserted at the midpoint of the multilayer as a defect layer and can be conveniently
used to make the field intensity inside the slab significantly stronger than the intensity of the field
incident on the Cantor structure
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