1,721,513 research outputs found
Resonant inelastic x-ray scattering study of Ca3Ru2O7
No full textWe present a combined oxygen K-edge x-ray absorption spectroscopy and resonant inelastic x-ray scattering (RIXS) study of the bilayer ruthenate Ca3 Ru2 O7 . Our RIXS experiments on Ca3 Ru2 O7 were carried out on the overlapping planar and interplanar oxygen resonances, which are distinguishable from the apical one. Comparison to equivalent oxygen K-edge spectra recorded on band-Mott insulating Ca2RuO4 is made. In contrast to Ca2 RuO4 spectra, which contain excitations linked to Mott physics, Ca3 Ru2 O7 spectra feature only intra-t2g ones that do not directly involve the Coulomb energy scale. As found in Ca2RuO4, we resolve two intra-t2g excitations in Ca3Ru2O7. Moreover, the lowest lying excitation in Ca3Ru2O7 shows a significant dispersion, revealing a collective character different from what is observed in Ca2RuO4. Theoretical modeling supports the interpretation of this lowest energy excitation in Ca3Ru2O7 as a magnetic transverse mode with multiparticle character, whereas the corresponding excitation in Ca2RuO4 is assigned to combined longitudinal and transverse spin modes. These fundamental differences are discussed in terms of the inequivalent magnetic ground-state manifestations in Ca2RuO4 and Ca3Ru2O7
The Davisson–Germer experiment
No full textIn this chapter, we discuss the well celebrated Davisson-Germer experiment, that demonstrates the wave nature of the electron. Then, we present the table-top apparatus that reproduces the original experiment. We point out that such experimental set-up is easily usable by students, and it allows to measure the electron wavelength, thus confirming de Broglie’s hypothesis
Issues related to gluten-free diet in celiac disease
No full textPURPOSE OF REVIEW: In the last few years, knowledge about coeliac disease has significantly improved, resulting in a better understanding of disease pathogenesis, diagnosis and therapy. This review describes the latest progress in research concerning treatment with gluten-free diet in patients with coeliac disease.
RECENT FINDINGS: Gluten-free diet is generally admitted as effective therapy in symptomatic patients, but a life-long dietary treatment in some challenging cases such as 'silent' and 'latent' patients is under discussion. Tolerance to gluten may be acquired later in life, but, as latency may be transient, a strict follow-up is necessary in these patients. The composition of gluten-free diet needs a better definition; latest evidence demonstrates that oats are tolerated by most patients with coeliac disease. Finally, the amount of gluten permitted in gluten-free products is still a matter of debate; significant progress has been made in the sensitivity of techniques for gluten detection, but the daily amount of gluten that can be safely consumed is not yet defined.
SUMMARY: Gluten-free diet remains the cornerstone of therapy of coeliac disease. More studies addressing the need of gluten-free diet for cases of 'potential' coeliac disease are necessary, as well as studies linking the best available analytical detection of gluten to the clinical threshold of tolerance
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
Characterization of collagen-like heterotrimers: implications for triple-helix stability.
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