86,711 research outputs found
A neutron diffraction study of macroscopically entangled proton states in the high temperature phase of the KHCO3 crystal at 340 K
No full textInternational audienceWe utilize single-crystal neutron diffraction to study the structure of potassium hydrogen carbonate (KHCO) and macroscopic quantum entanglement above the phase transition at K. Whereas split atom sites could be due to disorder, the diffraction pattern at 340 K evidences macroscopic proton states identical to those previously observed below by F. Fillaux et al., (2006 \textit{J. Phys.: Condens. Matter} \textbf{18} 3229). We propose a theoretical framework for decoherence-free proton states and the calculated differential cross-section accords with observations. The structural transition occurs from one ordered structure () to another ordered structure. There is no breakdown of the quantum regime. It is suggested that the crystal is a macroscopic quantum object which can be represented by a state vector. Raman spectroscopy and quasi-elastic neutron scattering suggest that the state vector is a superposition of the state vectors for two -like structures symmetric with respect to planes
Methyl group tunnelling studies in calixarenes
No full textInelastic neutron scattering has been used to study the tunnelling of methyl groups belonging to several guest molecules (toluene, p-xylene, gamma-picoline) incarcerated in a host calixarene matrix. In all the cases investigated, the low tunnel-split librational states of the guest methyl groups. The main line occurs near 0.63 meV, very close to the CH3 quantum free rotor limit. In the toluence complex, the quantum regime persists at least up to 60 K. Effects of coupling between rotational and vibrational modes are discussed. Very subtle structural changes not revealed by diffraction measurements are suggested by the neutron spectroscopy results
Molecular Tunnelling in p-tert-butylcalix[4]arene(2:1)p-xylene
No full textInelastic neutron scattering has been used to study molecular tunnelling in the p-tert-butylcalix[4]arene(2:1)p-xylene complex. At low temperature the measured spectra show several bands between 0.63 and 2.6 meV which are interpreted as being due to transitions between tunnel-split librational states of the p-xylene methyl groups. Effects of coupling between a CH3 group and the whole p-xylene molecule have been observed. The rotational barrier provided by the host lattice is very small and the methyl groups behave as almost free quantum rotors
Variations on the Author
No full text“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
[Newspaper Clipping: Author Claims Evidence of Second JFK Assassin #1]
No full textNewspaper article titled "Author Claims Evidence of Second JFK Assassin." The article states that author Richard J. Whalen concluded "that there is circumstantial evidence to support the theory of a second assassin in the shooting of President John F. Kennedy.
A new class of compounds suited to study the torsional dynamics in the quantum regime: the calixarenes
No full textInelastic neutron scattering spectroscopy has been used to study the rotational dynamics of methyl groups in the p-tert butylcalix [4] arene(1:1)toluene complex. The neutron scattering function shows several lines between 0. 16 and 2.6 meV, and can be satisfactorily reproduced by the single-particle model for rotational tunneling only if the presence of inequivalent sites is assumed, in contrast with the crystallographic determinations. An approach consistent with the room-temperature crystal structure and giving a satisfactory description of the experimental results is obtained by the quantum sine-Gordon model, which describes the dynamics of infinite chains of coupled methyl groups
Also By The Same Author: AKTiveAuthor, a Citation Graph Approach to Name Disambiguation
No full textThe desire for definitive data and the semantic web drive for inference over heterogeneous data sources requires co-reference resolution to be performed on those data. In particular, name disambiguation is required to allow accurate publication lists, citation counts and impact measures to be determined. This paper describes a graph-based approach to author disambiguation on large-scale citation networks. Using self-citation, co-authorship and document source analyses, AKTiveAuthor clusters papers, achieving precision of 0.997 and recall of 0.818 over a test group of eight surname clusters
John F. Kennedy telegram to Roosevelt
No full textJersey Homesteads (later the Borough of Roosevelt) was established in the 1930s as an agro-industrial cooperative community. It was established specifically for urban Jewish garment workers, many of whom had emigrated from Europe. President John F. Kennedy sent a telegram to the citizens of Roosevelt, New Jersey, apologizing for not being able to attend the memorial dedication in honor of former President Franklin Delano Roosevelt. (Jersey Homesteads became Roosevelt in 1945 in honor of the president.) President Kennedy expressed his gratitude to the people of Roosevelt for constructing the memorial, and commented that it will serve as a constant reminder of Roosevelt's good works
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