1,720,965 research outputs found
Sleep-dependent changes in regional circulations
No full textWhereas quiet sleep is characterized by modest quantitative changes in regional circulations, active sleep markedly affects both neural and local controls of the individual vascular beds. The integrated vasomotor patterns controlled by hypothalamic structures are those most perturbed during active sleep
Un modello di processo semplificato per l'ottimazione delle condizioni di estrusione delle paste alimentari
No full textLa produzione delle paste alimentari per estrusione attraverso la sola trafila, porta ad ottenere distribuzioni dimensionali spesso al di fuori dei limiti di accettabilità e richiede l’installazione di piastre di compensazione di difficile progettazione e scelta.
Nel presente lavoro si propone un approccio semplificato alla modellazione matematica dell’estrusione, consistente in un modello matematico semplificato della distribuzione della temperatura ed un modello matematico semplificato del comportamento reologico dell’impasto, che considera l’idratazione e la temperatura. Scopo ultimo della metodologia sviluppata è fornire uno strumento utilizzabile nella progettazione delle piastre di compensazione
Regional splanchnic blood flow during sleep in the rabbit
No full textRegional splanchnic blood flow (rSBF) was measured in rabbits with the radioactive microsphere technique. No statistically significant changes occurred in rSBF or vascular conductances in relation to the different states of the sleep-waking cycle (quiet-wakefulness, synchronized sleep, and desynchronized sleep). © 1990 Springer-Verlag
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
Brain blood flow and extracerebral carotid circulation during sleep in rat
No full textCerebral blood flow (CBF) and blood flow (BF) in extracerebral head structures were measured during the sleep-wake cycle in rats using radioactive microspheres. While no statistically significant changes occured in the transition from Waking to quiet sleep (also referred to as synchronized or non-REM Sleep), CBF increased significantly in active sleep (AS, also referred to as desynchronized or REM Sleep) in all structures considered, with the sole exception of the cerebellum. In extracerebral head structures, no significant state-dependent BF changes were found. Factor Analysis however extracted a common factor accounting for BF variability in the external carotid circulation. This factor was uncorrelated with CBF changes in AS, suggesting independent regulation of the two vascular beds in this sleep state. © 1994
Loss of integrative control of peripheral circulation during desynchronized sleep
No full textRegional blood flow (BF) changes during sleep were measured in rabbits at low, neutral, and high ambient temperatures (T(a)) with radioactive microspheres. At both low and high T(a), peripheral vasomotor changes at the onset of desynchronized sleep (DS) were incompatible with thermoregulatory homeostasis. At low T(a), BF decreased in muscle (with the disappearance of shivering), whereas it increased in the arteriovenous anastomoses (AVA) and in the splanchnic bed. At high T(a), BF decreased in muscle (with the disappearance of panting) and in the AVA, whereas it increased in the splanchnic bed. An impaired central nervous regulation underlies the disruption of peripheral circulation patterns in this sleep stage. The lack of adaptive vasomotor adjustments in DS, which has little consequence in normal conditions, may become relevant in cardiovascular pathophysiology when BF redistribution through increased neurogenic vasomotor activity becomes a major compensating mechanism
Shivering during sleep: Relationship between muscle blood flow and fiber type composition
No full textThe present study considers in rabbit: i) the relationship between muscle blood flow (BF) increase and fiber-type composition during shivering; ii) the influence of the vigilance states (Quiet Wakefulness, QW; Synchronized Sleep, SS; Desynchronized Sleep, DS) on this relationship. The results show that muscle BF increase during shivering is proportional to the slow-twitch oxidative (SO) fiber component in QW and SS; in DS the proportionality is lost. This is in accordance with the disappearance of shivering, together with all thermoregulatory effector responses, in this sleep state. Another muscle circulation pattern occurring at low ambient temperature, the relationship between BF increase and muscle depth, also disappears in DS. This confirms that the integrative control of muscle circulation, like other integrative mechanisms, is impaired during DS. © 1992 Birkhäuser Verlag
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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