Search results for "MECHANISMS"
showing 10 items of 587 documents
Dissipative Processes and Their Role in the Evolution of Radio Galaxies
2019
Particle acceleration in relativistic jets to very high energies occurs at the expense of the dissipation of magnetic or kinetic energy. Therefore, understanding the processes that can trigger this dissipation is key to the characterization of the energy budgets and particle acceleration mechanisms at action in active galaxies. Instabilities and entrainment are two obvious candidates to trigger dissipation. On the one hand, supersonic, relativistic flows threaded by helical fields, as expected from the standard formation models of jets in supermassive black-holes, are unstable to a series of magnetohydrodynamical instabilities, such as the Kelvin-Helmholtz, current-driven, or possibly the p…
A conceptual model of feedback mechanisms in adjusted affordances – Insights from usage of a mental mobile health application
2023
Affordance theory provides one of the most prominent lenses through which the socio-technical aspects of a system’s use can be investigated and understood. In this context, the literature has proposed that perceived and actualized affordances may be adjusted over time. Yet, how the adjustment of affordances occurs has not been explained in detail. Thus, in this article, we develop a conceptual model of feedback mechanisms that includes a more explicit description of how affordances are perceived by users, whether actualized and adjusted. With the model, we introduce the central concept of a generative base, out of which affordance perceptions emerge and which can be updated through affordan…
A computational model of postprandial adipose tissue lipid metabolism derived using human arteriovenous stable isotope tracer data
2019
Given the association of disturbances in non-esterified fatty acid (NEFA) metabolism with the development of Type 2 Diabetes and Non-Alcoholic Fatty Liver Disease, computational models of glucose-insulin dynamics have been extended to account for the interplay with NEFA. In this study, we use arteriovenous measurement across the subcutaneous adipose tissue during a mixed meal challenge test to evaluate the performance and underlying assumptions of three existing models of adipose tissue metabolism and construct a new, refined model of adipose tissue metabolism. Our model introduces new terms, explicitly accounting for the conversion of glucose to glyceraldehye-3-phosphate, the postprandial …
Effects of cigarette smoking or ingestion of nicotine on platelet 5-hydroxytryptamine (5-HT) levels in smokers and non-smokers.
1992
Platelets of healthy smokers and non-smokers were prepared and their content of 5-hydroxytryptamine was determined by HPLC with electrochemical detection. Platelet 5-HT levels in smokers (728 +/- 156 pmol per 10(8) platelets, mean +/- SEM, n = 9) were significantly higher than those in non-smokers (353 +/- 156 pmol per 10(8) platelets, n = 11). Smoking of a single cigarette caused a transient increase in platelet 5-HT levels by about 350% in non-smokers, but had no additional effect in smokers. Similarly, chewing of nicotine gum (4-8 mg nicotine) resulted in a transient increase in platelet 5-HT by about 100% in non-smokers, but not in smokers. In conclusion, smoking of cigarettes can cause…
Testing the Cross-Cultural Robustness of the Minority Stress Model in Gay and Bisexual Men
2017
The study tests the cross-cultural robustness of the minority stress model using a most different systems approach. Data from Western European, Eastern European (including Russian), Indian, Philippine, and Thai gay and bisexual men was obtained online. The final sample consisted of N = 90,467 participants who reported their level of satisfaction with life, victimization, felt stigma, and internalized homonegativity, as well as their disclosure status and sociodemographic details. Stepwise linear regressions were conducted on reported levels of satisfaction with life. Higher levels of victimization, felt stigma, and internalized homonegativity predicted lower satisfaction with life in all gr…
The role of eating disorders features, psychopathology, and defense mechanisms in the comprehension of orthorexic tendencies
2022
Abstract Purpose Recent studies pointed out the importance to distinguish orthorexia nervosa (ON) from non-problematic forms of interest with healthy eating. This distinction needs to be further explored since it may favor a better comprehension of the relationship between orthorexic behaviors and psychopathology and lead to an improved understanding of the psychological processes implicated in ON. Therefore, the aim of the current study was to investigate the associations between ON and the core features of eating disorders (EDs), psychopathological symptoms and defense mechanisms, by differentiating three groups of individuals: an ON symptoms group, a healthy-eating control group, and a n…
Carriage of Enterobacteria Producing Extended-Spectrum β-Lactamases and Composition of the Gut Microbiota in an Amerindian Community
2015
ABSTRACT Epidemiological and individual risk factors for colonization by enterobacteria producing extended-spectrum beta-lactamases (E-ESBL) have been studied extensively, but whether such colonization is associated with significant changes in the composition of the rest of the microbiota is still unknown. To address this issue, we assessed in an isolated Amerindian Guianese community whether intestinal carriage of E-ESBL was associated with specificities in gut microbiota using metagenomic and metatranscriptomic approaches. While the richness of taxa of the active microbiota of carriers was similar to that of noncarriers, the taxa were less homogeneous. In addition, species of four genera,…
Exploring relations among mindfulness facets and various meditation practices: Do they work in different ways?
2017
Several meditation practices are associated with mindfulness-based interventions but little is known about their specific effects on the development of different mindfulness facets. This study aimed to assess the relations among different practice variables, types of meditation, and mindfulness facets. The final sample was composed of 185 participants who completed an on-line survey, including information on the frequency and duration of each meditation practice, lifetime practice, and the Five-Facet Mindfulness Questionnaire. A Multiple Indicators Multiple Causes structural model was specified, estimated, and tested. Results showed that the Model's overall fit was adequate: chi(2) (1045) =…
Is Cybervictimization Associated with Body Dissatisfaction, Depression, and Eating Disorder Psychopathology?
2018
Studies carried out in nonclinical samples have found an association between cyberbullying victimization and eating disorder (ED) psychopathology (negative emotions, low self-esteem, unhealthy eating behaviors, and body dissatisfaction); however, these previous studies were carried out with participants without an ED diagnosis. To extend the knowledge in this area of research, we aim to confirm these associations in two different samples: on the one hand, a sample composed of participants with ED diagnoses and, on the other hand, a sample composed of participants at high risk of ED. In study 1, the sample was composed of 80 participants diagnosed with EDs: 41.2 percent, n = 33, matched buli…
Adaptive modes of rumination: the role of subjective anger.
2015
Rumination has been demonstrated to have negative consequences on affect, behaviour, and physiological markers. Recent studies, however, suggest that distinct "modes" of anger-associated rumination may lead to several positive consequences. Previous research primarily used recall procedures of anger episodes to elicit anger. By contrast, the present study focused on the effect of subjective anger on the process of rumination and tested its effects in a "staged" social interaction where a confederate provoked participants. Subsequently, participants engaged in rumination about the anger-eliciting event either in an abstract-distanced or a concrete-immersed rumination mode. Results showed an …