1,721,012 research outputs found
Heart rate variability and inflammation: A meta-analysis of human studies
No full textThe inflammatory reflex is known as the body's primary defense against infection and has been implicated in a number of diseases. The magnitude of the inflammatory response is important, as an extreme or insufficient response can be differentially harmful to the individual. Converging evidence suggests that the autonomic nervous system (ANS) regulates the inflammatory reflex. Heart rate variability (HRV) can be separated into components that primarily reflect parasympathetic (PNS) or vagal activity (i.e., indices of vagally mediated HRV) and a combination of both sympathetic (SNS) and PNS influences. Given the physiological relation between the vagus and inflammatory processes, one would expect to find higher HRV, especially indices of vagally-mediated HRV, to be associated with decreased levels of inflammation via the cholinergic anti-inflammatory pathway. However, existing findings here are mixed, such that studies have also shown a positive association between indices of HRV and markers of inflammation. Therefore, the present meta-analysis aimed to synthesize existing studies, estimating the general direction and strength of the relationship between different indices of HRV and inflammatory markers. A systematic search of the literature yielded 2283 studies that were screened for inclusion eligibility (159 studies eligible for inclusion); in sum, 51 studies reported/provided adequate information for inclusion in meta-analyses. Results generally showed negative associations between indices of HRV and markers of inflammation. In this regard, the standard deviation of R-R intervals (SDNN) and power in the high frequency band of HRV (HF-HRV) showed the strongest and most robust associations with inflammatory markers compared to other time- and frequency-domain measures of HRV. Overall, we propose that indices of HRV can be used to index activity of the neurophysiological pathway responsible for adaptively regulating inflammatory processes in humans
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The cardiovascular conundrum in ethnic and sexual minorities: a potential biomarker of constant coping with discrimination
Get PDFBackground: A paradoxical profile of greater elevated sympathetic vasoconstriction (increased total peripheral resistance, TPR) and increased vagally-mediated heart rate variability (HRV) -the so-called Cardiovascular Conundrum- has been reported in African Americans (AAs) both at rest and in response to orthostasis. Whereas some authors have attributed this pattern to genetic factors, others have pointed to the potential role of coping with repeated racial discrimination.
Objective: To disentangle between these alternative explanations, we have examined the hemodynamic profile of another population that is likely to be exposed to episodes of discrimination, i.e., sexual minorities.
Methods: The first study was conducted on a sample of AAs and European Americans (EAs) with the aim of replicating previous results on the Cardiovascular Conundrum. In the second study, lesbian, gay, and bisexual (LGB) people, matched by age and sex with heterosexual participants, underwent a hemodynamic and autonomic assessment at rest and during an emotional (in the experimental group, both LGB-related and non LGB related), and a cognitive stressor.
Results: The first study confirmed a pattern of higher resting HRV, paired with higher TPR, in AAs compared to EAs. In the second study, compared to heterosexuals, the LGB group showed the Cardiovascular Conundrum pattern, characterized by greater HRV and higher TPR at baseline and a more vascular hemodynamic profile and prominent compensation deficit in response to both tasks, and particularly during the LGB-related emotional task. However, in LGB only, the vascular response was negatively correlated with perceived discrimination.
Conclusion: Present preliminary results are discussed in terms of maladaptive physiological consequences of exposure to chronic stress and the chronic use of dysfunctional emotion regulation strategies such as suppression
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Hemodynamic profile and compensation deficit in African and European Americans during physical and mental stress
No full textIncreased vascular reactivity to stress has been suggested to contribute to the greater risk for developing hypertension in African Americans. Here, we examined the way (hemodynamic profile) and the extent to which (compensation deficit) cardiac output and total peripheral resistance compensate for each other in determining blood pressure responses to a physical (orthostasis) and a mental (anger recall) stress task, in normotensive African American (AA, n = 30) and European American (EA, n = 48) college students. Blood pressure stress reactivity did not differ as a function of race. However, AAs showed a prominent vascular hemodynamic profile and a significant compensation deficit in response to both tasks, while EAs showed no hemodynamic response to orthostasis and a mixed profile in response to anger recall. The present findings demonstrate a more prominent vascular hemodynamic reactivity to stress in AAs, which could contribute to the pathogenesis of hypertension in this ethnic group
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Gender Differences on the Relationship among Resting Heart Rate Variability, Self-Reported Drug Abuse, and Difficulties in Emotion Regulation
Get PDFEarly drug use might to lead to drug addiction; the earlier individuals begin to engage in risky drug use, the more likely they are to engage in later drug abuse. Therefore, early intervention is warranted. This study explored individual differences in drug use tendencies in young and healthy adults. Specifically, I examined how self-reported emotion regulation (ER) difficulties and inhibition abilities, as indexed by resting heart rate variability (HRV), might predict risky drug use tendencies in young adults. I further considered these associations stratified by women and men. Novel results showed self-reported (or perceptions of) difficulties in ER were associated with higher drug usage in the full sample and this association was significantly stronger in women than men. Among the six different facets of ER difficulties, only those related to impulse control difficulties and limited access to ER strategies were most related to risky drug usage in women but not men. The other four facets of ER difficulties were not significantly different between men and women. An indirect association was found between resting HRV and drug use, mediated by self-reported difficulties in ER, particularly in women. Overall, results indicate that lower HRV and difficulties in ER indirectly and directly, respectively, predict risky drug use in women. These data are in line with research suggesting women might engage in risky drug use primarily for stress regulation while men might engage in risky drug activity irrespective of both resting HRV and difficulties in ER. Clinical implications are discussed
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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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Multi-Ethnic Variation in the Ties That Bind Rumination and Heart Rate Variability: Implications for Health Disparities
Get PDFHigher self-reported rumination, a common form of trait perseverative cognition, is linked with lower resting heart rate variability (HRV), which indicates poorer cardiac function and greater disease risk. A prior meta-analysis and systematic review indicates that in samples with fewer European Americans, the association of rumination with both heart rate and blood pressure was stronger. Thus, trait rumination may be more strongly associated with HRV among ethnically minoritized populations, but few studies exist. The current study therefore investigated whether differences in the association of self-reported rumination with resting HRV varied by ethnicity in a sample (N = 513; Mage = 19.41; 226 Women) of self-identified African Americans (n = 110), Asian Americans (n = 84), and European Americans (n = 319). Participants completed a 5-min baseline period to assess resting HRV, followed by the Ruminative Responses Scale, which contains three facets of rumination including brooding, depressive, and reflective rumination. On average, Asian Americans reported higher levels of rumination relative to European Americans. African Americans had higher average HRV than Asian Americans. Adjusting for covariates, higher self-reported rumination was significantly associated with lower HRV in both African and Asian Americans, but not significantly so in European Americans. This finding was consistent for brooding and reflective, but not depressive rumination. Overall, this study lends insight into a psychological mechanism – rumination – that may impact health disparities among ethnically minoritized individuals, contributing to an understanding of how stress gets under the skin among such populations
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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