1,721,050 research outputs found
Nonlocal properties of the time-dependent Casimir-Polder interaction between three atoms
No full textConfinement and high-order harmonic generation by a repulsive potential
No full textThe dynamics of an electron wave packet in the presence of laser radiation and of a one-dimensional
repulsive soft-core potential is investigated. For different laser intensities and for different initial positions of
the electron wave packet, these results are compared with those for an attractive potential. The repulsive
potential is capable of confining the electron quite efficiently under appropriate conditions. In these conditions,
the electron is shown to emit a high harmonic spectrum similar to that emitted by the more conventional
attractive potential. It is thus argued that recombination into an atomic bound state as required by the three step
model is not essential for the emission of high harmonics
Space-time localization of the radiation emitted by an electromagnetically driven charge and the question of the position of an electron
No full textWe study the electromagnetic spectrum emitted by a free charge driven by a strong laser field in the proximity of a stationary scattering centre that acts as an accelerating third body. We show that under the most general conditions the radiation is emitted close to the scatterer and during a well-defined time interval. Thus it should be possible, at least in principle, to determine the position of the electron by observing the radiation that it is emitting
Pigs contra circovirus. Protection of pigs vaccinated with inactivated subunit vaccine [Sertések kontra circovírus inaktivált alegységvakcinával immunizált sertések védettsége]
No full textThe authors carried out vaccination on a pig farm fattening for high weight, where they demonstrated earlier the presence of and loss due to porcine circovirus (PCV2). From the two groups (261-261 animals) kept under the same conditions, one was vaccinated with sub-unit vaccine at weaning, at the age of 27 days, while the other was not vaccinated. At the time of vaccination all pigs of both groups were negative by PCR test. In the control group 4 weeks after weaning and also before slaughtering PCVD occurred in clinical signs, and PCR-test proved viraemia. Death rate and culling was higher in all stage of rearing in the control group: all death was 12.6 v. 4.2%, and culling 13.8 v. 7.3%. Carcase weight of pigs slaughter on 303rd day was larger by 5.1 kg in the vaccinated group. Single vaccination with inactivated sub-unit vaccine at the weaning gave adequate protection for 9 months against circovirus infection
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
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