1,721,123 research outputs found
Allenamento dei muscoli respiratori: tecniche e risultati.
No full textI muscoli respiratori come quelli locomotori possono essere allenati. Il loro allenamento viene
sottovalutato, ma, se preso in considerazione, potrebbe migliorare la performance di un atleta o la qualità di vita di un soggetto con problematiche respiratorie
Chondrule thermal history from unequilibrated H-chondrites: A transmission and analytical electron microscopy study
No full textSixteen texturally different (porphyritic, barred, radial, cryptocrystalline) FeO-rich chondrules from the unequilibrated ordinary chondrites Brownfield, Frontier Mountain (FRO) 90003 and FRO 90032 were characterized by optical and scanning electron microscopy and then thoroughly studied by transmission and analytical electron microscopy. Nanotextural and nanochemical data indicate similar thermal evolution for chondrules of the same textural groups; minor, yet meaningful differences occur among the different groups. Olivine is the earliest phase formed and crystallizes between 1500 and 1400degreesC. Protoenstatite crystallizes at temperatures higher than 1350-1200degreesC; it later inverts to clinoenstatite in the 1250-1200degreesC range. Enstatite is surrounded by pigeonitic or (less frequently) augitic rims; the minimal crystallization temperature for the rims is 1000degreesC; high pigeonite later inverts to low pigeonite, between 935 and 845degreesC. The outer pigeonitic or augitic rims are constantly exsolved, producing sigmoidal augite or enstatite precipitates; sigmoidal precipitates record exsolution temperatures between 1000 and 640 T. Cooling rate (determined using the speedometer based upon ortho-clinoenstatite intergrowth) was in the order of 50-3000 degreesC/h at the clinoenstatite-orthoenstatite transition temperature (close to 1250-1200degreesC), but decreased to 5-10 degreesC/h or slower at the exsolution temperature (between 1000 and 650degreesC), thus revealing nonlinear cooling paths. Nanoscale observations indicate that the individual chondrules formed and cooled separately from 1500degreesC down to at least 650degreesC. Accretion into chondritic parent body occurred at temperatures lower than 650degreesC
Crystal chemical investigations on rare zirconium-niobium silicates of the Alfred Lacroix collection of the Muséum National d’Histoire Naturelle (Paris)
No full textSigmoidal exsolution by internal shear stress in pyroxenes from chondritic meteorites
No full textPyroxenes of pigeonitic and augitic bulk compositions in H3-4 chondritic meteorites commonly exhibit sigmoidal precipitates, rather than the elsewhere common lamellar associations. Most often, submicrometric sigmoids with calcic clinopyroxene composition occur within clinoenstatite; more rarely, clinoenstatite sigmoids occur within calcic clinopyroxene. The sigmoids appear as '001' terminated lamellae, with terminations rotated in opposite directions towards the '100' orientation. Pre-exsolution pigeonite and augite formed at temperatures higher than 980degreesC, whereas sigmoidal exsolution occurred between 990 and 830degreesC. Local anomalous lattice parameters determined by electron diffraction suggest that lattice parameters are most strained where the exsolution texture is most poorly defined. Shear strain occurs during exsolution due to mismatching lattice parameters and variable beta angles. In response to shear stress, the lamellae relax and assume sigmoidal strained morphologies. Sigmoidal exsolution is strongly controlled by (100) orthoenstatite stacking faults that possibly trigger exsolution
Crystallization sequences and cooling histories of pyroxenes in IIAB and IIB chondrules from unequilibrated H-chondrites
No full text
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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