1,122 research outputs found
Effect of phasic contractions and tone of the proximal stomach on triggering of transient lower esophageal sphincter relaxation
No full textWe hypothesized that transient lower esophageal sphincter relaxation (TLESR) is triggered by a discrete motor event, i.e., a phasic contraction or a tonic change of the proximal stomach. The combined esophageal manometry-gastric barostat tracings obtained from 11 healthy subjects during 2-hr continuous isobaric gastric distension were reviewed. Volume waves, i.e., phasic contractions, were analyzed in the 1 and 5 min before onset of each TLESR and in corresponding control periods. Intrabag volume, i.e., proximal gastric tone, was also measured in the 5-min periods. The number of volume waves was similar in the 1- and 5-min pre-TLESR and control periods (0 [0-1], median [IQ range], vs 0 [0-1] and 4 [0.8-5] vs 3 [2-4], respectively], and so were their amplitude, duration, and frequency distribution. Five-minute intrabag volume was also similar (529 ± 77 [mean ± SE] vs 532 ± 74 ml). Our observations suggest that TLESR is not triggered by a preceding phasic contraction or by a different tone of the proximal stomach
Tecnica, estetica e processi comunicativi nel dibattito sulle “due culture”
No full textGli anni Cinquanta e Sessanta furono contrassegnati dal vertiginoso incremento di alcuni settori industriali (chimica, elettrodomestici, automobile, telecomunicazioni) e dalla diffusione della cultura di massa. Questo articolo ricostruisce il dibattito "due culture" in Italia focalizzandosi sull'impatto dello sviluppo della cibernetica e dell'informatizzazione sull'arte, la letteratura e i mass media.This article offers an historical reconstruction of the “two cultures” debate in Italy, focusing on the impact on art, literature and mass media of the technical evolution from mechanization to direct interaction with computing electronic devices dur- ing the 1960s. The concept of interaction in the Information science functioned beyond a purely technological paradigm, as showed by Umberto Eco in Opera Aperta (1962) and Apocalittici ed integrati (1964), emphasizing on openness and entropy in the poetics of con- temporary art, and the dissolution of borders between artistic experimentation, mass media and quotidian life. In his influential lecture Cibernetica e fantasmi (1967) Italo Calvino argued that Artificial intelligence provided a new model of dynamic transdisciplinary exchange for the investigation of rules and patterns embedded in writing processes, exploring the possibility of a «literary automaton», capable of replacing the author
Is transient lower esophageal sphincter relaxation triggered by phasic contractions or tonic changes of the proximal stomach?
No full textEffect of prolonged gastric distension on motor function of LES and of proximal stomach
No full textGastric distension is a potent stimulus of transient lower esophageal sphincter (LES) relaxation. To investigate the time effect of prolonged gastric distension on the rate of transient LES relaxations, LES pressure, and the motor and sensory functions of the proximal stomach, we performed a continuous isobaric distension of the proximal stomach at the 75% threshold pressure for discomfort for 2 h in seven healthy subjects. A multilumen assembly incorporating a sleeve and an electronic barostat was used. The rate of transient LES relaxations (n/30 min) was constant during the first hour [4.1 ± 1.2 (0-30 min) and 5.4 ± 1.1 (30-60 min)] but markedly decreased (P < 0.05) in the second hour [2.1 ± 0.5 (60-90 min) and 2.3 ± 0.9 (90-120 min)], whereas LES pressure, baseline volume and volume waves within the gastric bag, hunger, and fullness did not change throughout the experiment. It is concluded that the rate of transient LES relaxations decreases with time during prolonged gastric distension, thus suggesting that this type of stimulus should not be used in sequential experimental conditions
La carta idrogeologica dell'Italia meridonale. Metodi ed analisi territoriali per l'identificazione e la caratterizzazione dei corpi idrici sotterranei (Direttiva 2000/60/CE)
No full textNel presente lavoro è illustrata la sintesi dei risultati di uno studio sulle risorse idriche sotterranee dell’Italia Meridionale (Allocca et alii, 2007), sviluppato nell’ambito del programma INTERREG IIC e finanziato dalla CEE. Le analisi condotte sono state finalizzate a ricostruire un quadro sintetico, ma dettagliato, dello stato delle conoscenze delle risorse idriche sotterranee dell’Italia meridionale continentale e della sua attuale utilizzazione. I principali prodotti interpretativi conseguiti sono: 1) carta idrogeologica, alla scala 1:250.000, rappresentativa di tutte le unità/strutture idrogeologiche che, per estensione e tipologia, hanno rilevanza a livello regionale; 2) note illustrative che sintetizzano lo stato delle conoscenze per ciascuna unità/struttura idrogeologica. I metodi di analisi e i risultati ottenuti rappresentano la base conoscitiva attualmente richiesta dalla Direttiva 2000/60/CE, agli Stati Membri, riguardante l’identificazione e la caratterizzazione idrogeologica dei corpi idrici sotterranei, che abbiamo considerato non come volumi di acque sotterranee (sensu Direttiva 2000/60/CE), bensì come corpi geologici acquiferi (Meinzer, 1923)
Assessing the impact of seasonal rainfall anomalies on catchment-scale water balance components.
No full textAlthough water balance components at the catchment scale are strongly related to annual rainfall, the availability of water resources in Mediterranean catchments also depends on rainfall seasonality. Observed seasonal anomalies in historical records are fairly episodic, but an increase in their frequency might exacerbate water deficit or water excess if the rainy season shortens or extends its duration, e.g., due to climate change. This study evaluates the sensitivity of water yield, evapotranspiration, and groundwater recharge to changes in rainfall seasonality by using the Soil Water Assessment Tool (SWAT) model applied to the upper Alento River catchment (UARC) in southern Italy, where a long time series of daily rainfall is available from 1920 to 2018. We compare two distinct approaches: (i) a “static” approach, where three seasonal features (namely rainy, dry, and transition fixed-duration 4-month seasons) are identified through the standardized precipitation index (SPI) and (ii) a “dynamic” approach based on a stochastic framework, where the duration of two seasons (rainy and dry seasons) varies from year to year according to a probability distribution. Seasonal anomalies occur when the transition season is replaced by the rainy or dry season in the first approach and when season duration occurs in the tails of its normal distribution in the second approach. Results are presented within a probabilistic framework. We also show that the Budyko curve is sensitive to the rainfall seasonality regime in UARC by questioning the implicit assumption of a temporal steady state between annual average dryness and the evaporative index. Although the duration of the rainy season does not exert a major control on water balance, we were able to identify season-dependent regression equations linking water yield to the dryness index in the rainy season
Higher-order Laguerre-Gauss interferometry for gravitational-wave detectors with in situ mirror defects compensation HIGHER-ORDER LAGUERRE-GAUSS INTERFEROMETRY ... A. ALLOCCA et al
No full textThe use of higher-order Laguerre-Gauss modes has been proposed to decrease the influence of thermal noise in future generation gravitational-wave interferometric detectors. The main obstacle for their implementation is the degeneracy of modes with same order, which highly increases the requirements on the mirror defects, beyond the state-of-the-art polishing and coating techniques. In order to increase the mirror surface quality, it is also possible to act in situ, using a thermal source, sent on the mirrors after a proper shaping. In this paper we present the results obtained on a tabletop Fabry-Pérot Michelson interferometer illuminated with a LG3,3 mode. We show how an incoherent light source can reduce the astigmatism of one of the mirrors, increasing the quality of the beam in one of the Fabry-Pérot cavities and then the contrast of the interferometer. The system has the potential to reduce more complex defects and also to be used in future gravitational-wave detectors using conventional Gaussian beams
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