1,721,123 research outputs found
Neurofeedback in Children with ADHD: Behavioral and neurocognitive treatment results post-intervention and at follow-up
Full text linkOosterlaan, J. [Promotor]Bink, M. [Copromotor]Maras, A. [Copromotor
Space weathering, reddening and gardening of asteroids: A complex problem
No full textThe association of ordinary chondrites and their parent bodies through their visible and near infrared spectra is still a debate. In fact, many asteroids show reddened spectra, while the ordinary chondrites do not. In the framework of the space weathering of asteroid surfaces, the interpretation of the reddening, darkening, and depletion of band depths is not as simple as previously described. We present a summary of the recent results in the study of the reddening of the spectra. To date, different mechanisms have been proposed to explain some properties of spectra, but a complete scenario capable of reproducing the whole set of observations is still missing
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
Carbonate groups in davyne: Structural and crystal-chemical considerations
No full textWe have refined the crystal structure of a specimen of davyne from Mt. Vesuvius, Italy, characterized by the presence of a significant amount of carbonate. The crystals have P6(3) symmetry, with cell parameters a 12.6916(9), c 5.3333(5) Angstrom. The chemical formula, obtained through electron-microprobe analysis, is (Na4.58K0.67Ca2.56)(Si6.06Al5.94O23.94)Cl-2.35(CO3)(0.88)(SO4)(0.19). According to its structural and chemical features, it may be classified as carbonate-bearing davyne, as it represents an intermediate phase between davyne sensu stricto and a hypothetical CO3 end-member. The carbonate groups are located inside the large channel as in cancrinite sensu stricto; their position is influenced by the presence of a limited number of SO4 groups. In fact, the triplets of oxygen atoms of the carbonate groups may alternatively be involved in the tetrahedral coordination of SO4. Because of the short C-C contacts, a deviation from stoichiometry may be expected. This fact, as well as a deficiency of cations, were observed in the structural refinement and confirmed by the electron-microprobe data
Structural features, crystal chemistry and long-range Si,Al order of the natural phases of the cancrinite group
No full text- …
