Validity of the Polar V800 heart rate monitor to measure RR intervals at rest

Purpose To assess the validity of RR intervals and short-term heart rate variability (HRV) data obtained from the Polar V800 heart rate monitor, in comparison to an electrocardiograph (ECG). Method Twenty participants completed an active orthostatic test using the V800 and ECG. An improved method for the identification and correction of RR intervals was employed prior to HRV analysis. Agreement of the data was assessed using intra-class correlation coefficients (ICC), Bland–Altman limits of agreement (LoA), and effect size (ES). Results A small number of errors were detected between ECG and Polar RR signal, with a combined error rate of 0.086 %. The RR intervals from ECG to V800 were significantly different, but with small ES for both supine corrected and standing corrected data (ES 0.999 for both supine and standing corrected intervals. When analysed with the same HRV software no significant differences were observed in any HRV parameters, for either supine or standing; the data displayed small bias and tight LoA, strong ICC (>0.99) and small ES (≤0.029). Conclusions The V800 improves over previous Polar models, with narrower LoA, stronger ICC and smaller ES for both the RR intervals and HRV parameters. The findings support the validity of the Polar V800 and its ability to produce RR interval recordings consistent with an ECG. In addition, HRV parameters derived from these recordings are also highly comparable

Influence of Dispersion Interactions on the Thermal Desorption of Nonplanar Polycyclic Aromatic Hydrocarbons on HOPG

A combination of low energy ion beam deposition and mass resolved thermal desorption spectroscopy is applied to analyze the binding behavior of two nonplanar polycyclic aromatic hydrocarbons (PAHs) to highly oriented pyrolytic graphite (HOPG) surfaces—also concerning their lateral dispersion interactions. In particular, the fullerene precursor C60H30 (FPC) and rubrene C42H28 are studied. Due to their smaller contact areas, both molecules exhibit significantly weaker binding energies to the HOPG surface compared to planar PAHs of similar size: C60H30 is bound to the surface by 3.04 eV, which is 0.6 eV lower than for a fully planar homologue. For rubrene, an isolated molecule–substrate binding energy of 1.59 eV is found, which is about 1 eV less than that of the corresponding planar homologue hexabenzocoronene C42H18. In contrast to FPC, rubrene shows a significant (intermolecular) lateral dispersion contribution to the binding energy as the submonolayer coverage increases

Are Children Like Werewolves? : Full Moon and Its Association with Sleep and Activity Behaviors in an International Sample of Children

In order to verify if the full moon is associated with sleep and activity behaviors, we used a 12-country study providing 33,710 24-h accelerometer recordings of sleep and activity. The present observational, cross-sectional study included 5812 children ages 9-11 years from study sites that represented all inhabited continents and wide ranges of human development (Australia, Brazil, Canada, China, Colombia, Finland, India, Kenya, Portugal, South Africa, United Kingdom, and United States). Three moon phases were used in this analysis: full moon (4 days; reference), half moon (5-9 days), and new moon (+10-14 days) from nearest full moon. Nocturnal sleep duration, moderate -to vigorous physical activity (MVPA), light-intensity physical activity (LPA), and total sedentary time (SED) were monitored over seven consecutive days using a waist -worn accelerometer worn 24 h a day. Only sleep duration was found to significantly differ between moon phases (-5 min/night shorter during full moon compared to new moon). Differences in MVPA, LPA, and SED between moon phases were negligible and non-significant (Peer reviewe

Left ventricular twist mechanics during incremental cycling and knee extension exercise in healthy men

Purpose: The objective of the present study was to investigate left ventricular (LV) twist mechanics in response to incremental cycling and isometric knee extension exercises. Methods: Twenty-six healthy male participants (age = 30.42 ± 6.17 years) were used to study peak twist mechanics at rest and during incremental semi-supine cycling at 30 and 60% work rate maximum (W) and during short duration (15 s contractions) isometric knee extension at 40 and 75% maximum voluntary contraction (MVC), using two-dimensional speckle tracking echocardiography. Results: Data presented as mean ± standard deviation or median (interquartile range). LV twist increased from rest to 30% W (13.21° ± 4.63° to 20.04° ± 4.76°, p  0.05), whilst twisting velocity increased (rest 89.15° ± 21.77° s to 75% MVC 124.32° ± 34.89° s, p  0.05) then increased from 40 to 75% MVC [−98.44 (43.54)° s to −138.42 (73.29)° s, p < 0.01]. Apical rotations and rotational velocities were greater than basal during all conditions and intensities (all p < 0.01). Conclusion: Cycling increased LV twist to 30% W which then remained unchanged thereafter, whereas twisting velocities showed further increases to greater intensities. A novel finding is that LV twist was unaffected by incremental knee extension, yet systolic and diastolic twisting velocities augmented with isometric exercise

Heart rate variability and the relationship between trauma exposure age, and psychopathology in a post-conflict setting

BACKGROUND: Cumulative exposure to potentially traumatic events (PTEs) increases risk for mental distress in conflict-affected settings, but the psychophysiological mechanisms that mediate this dose-response relationship are unknown. We investigated diminished heart rate variability (HRV) - an index of vagus nerve function and a robust predictor of emotion regulation capacity - as a vulnerability marker that potentially mediates the association between PTE exposure, age and symptoms of posttraumatic stress disorder (PTSD), psychological distress and aggressive behavior, in a community sample from Timor-Leste - a post-conflict country with a history of mass violence. METHOD: Resting state heart rate data was recorded from 45 cases of PTSD, depression and intermittent explosive disorder (IED); and 29 non-case controls. RESULTS: Resting HRV was significantly reduced in the combined case group compared with non-cases (p = .021; Cohen's d = 0.5). A significant mediation effect was also observed, whereby a sequence of increased age, reduced HRV and elevated PTSD symptoms mediated the association between PTE exposure and distress (B = .06, SE = .05, 95% CI = [.00-.217]) and aggression (B = .02, SE = .02, 95% CI = [.0003-.069])). CONCLUSION: The findings demonstrate an association between diminished resting HRV and psychopathology. Moreover, age-related HRV reductions emerged as a potential psychophysiological mechanism that underlies enhanced vulnerability to distress and aggression following cumulative PTE exposure

Getting to the heart of the matter: Does aberrant interoceptive processing contribute towards emotional eating?

According to estimates from Public Health England, by 2034 70% of adults are expected to be overweight or obese, therefore understanding the underpinning aetiology is a priority. Eating in response to negative affect contributes towards obesity, however, little is known about the underlying mechanisms. Evidence that visceral afferent signals contribute towards the experience of emotion is accumulating rapidly, with the emergence of new influential models of ‘active inference’. No longer viewed as a ‘bottom up’ process, new interoceptive facets based on ‘top down’ predictions have been proposed, although at present it is unclear which aspects of interoception contribute to aberrant eating behaviour and obesity. Study one examined the link between eating behaviour, body mass index and the novel interoceptive indices; interoceptive metacognitive awareness (IAw) and interoceptive prediction error (IPE), as well as the traditional measures; interoceptive accuracy (IAc) and interoceptive sensibility (IS). The dissociation between these interoceptive indices was confirmed. Emotional eaters were characterised by a heightened interoceptive signal but reduced meta-cognitive awareness of their interoceptive abilities. In addition, emotional eating correlated with IPE; effects that could not be accounted for by differences in anxiety and depression. Study two confirmed the positive association between interoceptive accuracy and emotional eating using a novel unbiased heartbeat discrimination task based on the method of constant stimuli. Results reveal new and important mechanistic insights into the processes that may underlie problematic affect regulation in overweight populations

Transpose domain filtering: Dual algorithms in adaptive filtering

In this paper, we describe a new parameter estimation methodology called transpose domain filtering (TDF). TDF is a processing formulation that that is different from conventional processing (e.g., beamscan processing) in that the weight vector is applied in the domain that lies transpose to the signal model. For a typical radar array processing problem, this means TDF would apply the weight vector in the snapshot domain as opposed to the element domain. We provide two examples of TDF applied to minimum variance distortionless response (MVDR) beamscan and code division multiple access (CDMA) synchronization. We later show that rank reduction techniques can be used in TDF, and then prove that when principal components rank reduction is applied to TDF, the result is mathematically equivalent to the better-known multiple signal characterization (MUSIC) algorithm. © 2008 IEEE

Signaling gender diversity through annual report pictures: A research note on image management

This research examines the differences in presentation of boards of directors in annual reports. Our sample consists of 472 corporations from the Fortune 500; 130 (342) of these corporations included (did not include) pictures of their boards of directors. The proportion of female directors was 11.0 percent for firms that did not include pictures of their boards and 14.5 percent for firms that included pictures of their boards in their annual reports. The difference in the gender mix of these two groups is significant (p = 0.0002). This indicates that firms with a higher percentage of women on their boards signal this fact to stockholders, investors, and other constituents by including pictures of their boards in their annual reports. © 2002, MCB UP Limite

Minority membership on boards of directors: The case for requiring pictures of boards in annual reports

Affirmative action and diversity continue to be contentious issues in the United States. Financial markets are still reeling from the effects of Enron, WorldCom and other corporate exemplars of corruption and malfeasance. The role of the board of directors in these scandals is the subject of serious and ongoing concern. Weak and/or ineffectual boards are often the consequences of old-boy networks and a lack of diversity in membership. This research study argues for an increased presence of gender and race diversity on boards of directors. Empirical evidence is presented that shows a significant increase in the presence of ethnic minorities and females when pictures of board members are included in annual reports. We suggest that requiring pictures of board members in annual reports and regulatory filings would result in a larger presence for gender and race diversity on boards of directors. This requirement is not a significant burden and merely represents compliance with the spirit and intent of the full disclosure principle. © 2004 Elsevier Ltd. All rights reserved