Browsing by Author "Torres, David"

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    Effects of changes in trunk inclination on ventilatory efficiency in ARDS patients: quasi-experimental study
    (2023) Benites, Martín H.; Torres, David; Poblete, Fabián; Labbé, Francisco; Bachmann, María C.; Regueira, Tomas E.; Soto, Leonardo; Ferre, Andrés; Dreyse, Jorge; Retamal Montes, Jaime
    Trunk inclination from semirecumbent head-upright to supine-flat positioning reduces driving pressure and increases respiratory system compliance in patients with acute respiratory distress syndrome (ARDS). These effects are associated with an improved ventilatory ratio and reduction in the partial pressure of carbon dioxide (PaCO2). However, these physiological effects have not been completely studied, and their mechanisms have not yet been elucidated. Therefore, this study aimed to evaluate the effects of a change in trunk inclination from semirecumbent (45°) to supine-flat (10°) on physiological dead space and ventilation distribution in different lung regions. Results: twenty-two ARDS patients on pressure-controlled ventilation underwent three 60-min steps in which trunk inclination was changed from 45° (baseline) to 10° (intervention) and back to 45° (control) in the last step. Tunk inclination from a semirecumbent (45°) to a supine-flat (10°) position resulted in a higher tidal volume [371 (± 76) vs. 433 (± 84) mL (P < 0.001)] and respiratory system compliance [34 (± 10) to 41 (± 12) mL/cmH2O (P < 0.001)]. The CO2 exhaled per minute improved from 191 mL/min (± 34) to 227 mL/min (± 38) (P < 0.001). Accordingly, Bohr’s dead space ratio decreased from 0.49 (± 0.07) to 0.41 (± 0.06) (p < 0.001), and PaCO2 decreased from 43 (± 5) to 36 (± 4) mmHg (p < 0.001). In addition, the impedance ratio, which divides the ventilation activity of the ventral region by the dorsal region ventilation activity in tidal images, dropped from 1.27 (0.83–1.78) to 0.86 (0.51–1.33) (p < 0.001). These results, calculated from functional EIT images, indicated further ventilation activity in the dorsal lung regions. These effects rapidly reversed once the patient was repositioned at 45°. Conclusions: a change in trunk inclination from a semirecumbent (45 degrees) to a supine-flat position (10 degrees) improved Bohr’s dead space ratio and reduced PaCO2 in patients with ARDS. This effect is associated with an increase in tidal volume and respiratory system compliance, along with further favourable impedance ventilation distribution toward the dorsal lung regions. This study highlights the importance of considering trunk inclination as a modifiable determinant of physiological parameters. The angle of trunk inclination is essential information that must be reported in ARDS patients.
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    Implicit and explicit attitudes toward people with Down syndrome: A study in schools with and without integration programmes in Chile
    (FUNDACION INFANCIA APRENDIZAJE, 2012) Sirlopu, David; Gonzalez, Roberto; Bohner, Gerd; Siebler, Frank; Millar, Andres; Ordonez, Gabriela; Torres, David; de Tezanos Pinto, Pablo
    Integrated education can reduce intergroup prejudice because enhance people contact. In this area, most researches have measured explicit attitudes using self-report questionnaires, but few studies have measure implicit attitudes for this objective. This article aims to evaluate both types of attitudes towards People with Down syndrome (PWDS). Eighty Chileans pupils (11-15 years) belonging from schools with and without integration programs participated in this study. Implicit attitudes were measured with Implicit Association Test (IAT). Results showed that all students, regardless from the school system, showed implicit bias towards PWDS. In explicit attitudes, although both samples exhibited low levels of prejudice, pupils from integrated schools expressed less anxiety towards PWDS. Finally, quality of contact, quantity of contact and salience were associated with less anxiety and more positive stereotypes towards PWDS.
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    Interparty attitudes in chile: Coalitions as superordinate social identities
    (BLACKWELL PUBLISHING, 2008) Gonzalez, Roberto; Manzi, Jorge; Saiz, Jose L.; Brewer, Marilynn; de Tezanos Pinto, Pablo; Torres, David; Aravena, Maria Teresa; Aldunate, Nerea
    This paper reports a survey (N = 1,465) conducted in Chile that was conceived to understand the role of coalition identification as an important sociopsychological mechanism for promoting positive affects toward own-coalition party members in a multiparty system, above and beyond interparty political differences. Participants judged their own political party, parties within coalitions (fellow coalition members and opposing parties), and political coalitions as a whole on affective dimensions (trust, liking, and admiration). The results provide substantial support for the five hypotheses addressed in the study. Overall, perceived interparty distance and political identity threat had a negative impact on affect toward coalition party members. Above and beyond these effects, identification with the coalition positively predicted affect toward allies. Ingroup party affect was positively correlated with affect toward own-coalition party members and own coalition as a whole, but was not negatively associated with affect toward opposing-coalition parties. Moreover, the relationship between own-party affect and affect toward own-coalition party members was mediated by affect toward own coalition. Overall, evidence for the benefits of promoting coalition identification in a multiparty system is provided and discussed alongside the limitations and practical implications derived from the study.
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    Revisando la Literatura #1
    (2018) Torres, David; Lacassie Quiroga, Héctor
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    Synchronization of neural activity across cortical areas correlates with conscious perception
    (SOC NEUROSCIENCE, 2007) Melloni, Lucia; Molina, Carlos; Pena, Marcela; Torres, David; Singer, Wolf; Rodriguez, Eugenio
    Subliminal stimuli can be deeply processed and activate similar brain areas as consciously perceived stimuli. This raises the question which signatures of neural activity critically differentiate conscious from unconscious processing. Transient synchronization of neural activity has been proposed as a neural correlate of conscious perception. Here we test this proposal by comparing the electrophysiological responses related to the processing of visible and invisible words in a delayed matching to sample task. Both perceived and nonperceived words caused a similar increase of local (gamma) oscillations in the EEG, but only perceived words induced a transient long-distance synchronization of gamma oscillations across widely separated regions of the brain. After this transient period of temporal coordination, the electrographic signatures of conscious and unconscious processes continue to diverge. Only words reported as perceived induced (1) enhanced theta oscillations over frontal regions during the maintenance interval, (2) an increase of the P300 component of the event-related potential, and (3) an increase in power and phase synchrony of gamma oscillations before the anticipated presentation of the test word. We propose that the critical process mediating the access to conscious perception is the early transient global increase of phase synchrony of oscillatory activity in the gamma frequency range.