14,496 research outputs found
4-Methyl-2,6-bis(phosphonomethyl)phenol dihydrate
The 4-methyl-2,6-bis(phosphomethyl)phenol molecule,
which crystallizes with two water molecules per asymmetric
unit, has approximate twofold symmetry and is
involved in extensive three-dimensional hydrogen bonding
in which every available OH group participates.
The principal dimensions include P--O 1.4981 (13)
and 1.5015 (14) ,~, four P--OH distances in the range
1.5395(14) to 1.5688(13) A, P--C 1.7857(17) and
1.7893 (17) ~k, and O...O intramolecular and intermolecular
hydro.gen-bond distances in the range 2.458 (2) to
2.866 (2) A
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Effect of Brief Biofeedback via a Smartphone App on Stress Recovery: Randomized Experimental Study.
BACKGROUND:Smartphones are often vilified for negatively influencing well-being and contributing to stress. However, these devices may, in fact, be useful in times of stress and, in particular, aid in stress recovery. Mobile apps that deliver evidence-based techniques for stress reduction, such as heart rate variability biofeedback (HRVB) training, hold promise as convenient, accessible, and effective stress-reducing tools. Numerous mobile health apps that may potentially aid in stress recovery are available, but very few have demonstrated that they can influence health-related physiological stress parameters (eg, salivary biomarkers of stress). The ability to recover swiftly from stress and reduce physiological arousal is particularly important for long-term health, and thus, it is imperative that evidence is provided to demonstrate the effectiveness of stress-reducing mobile health apps in this context. OBJECTIVE:The purpose of this research was to investigate the physiological and psychological effects of using a smartphone app for HRVB training following a stressful experience. The efficacy of the gamified Breather component of the Happify mobile health app was examined in an experimental setting. METHODS:In this study, participants (N=140) underwent a laboratory stressor and were randomly assigned to recover in one of three ways: with no phone present, with a phone present, with the HRBV game. Those in the no phone condition had no access to their phone. Those in the phone present condition had their phone but did not use it. Those in the HRVB game condition used the serious game Breather on the Happify app. Stress recovery was assessed via repeated measures of salivary alpha amylase, cortisol, and self-reported acute stress (on a 1-100 scale). RESULTS:Participants in the HRVB game condition had significantly lower levels of salivary alpha amylase during recovery than participants in the other conditions (F2,133=3.78, P=.03). There were no significant differences among the conditions during recovery for salivary cortisol levels or self-reported stress. CONCLUSIONS:These results show that engaging in a brief HRVB training session on a smartphone reduces levels of salivary alpha amylase following a stressful experience, providing preliminary evidence for the effectiveness of Breather in improving physiological stress recovery. Given the known ties between stress recovery and future well-being, this study provides a possible mechanism by which gamified biofeedback apps may lead to better health
Invariant manifolds and the geometry of front propagation in fluid flows
Recent theoretical and experimental work has demonstrated the existence of
one-sided, invariant barriers to the propagation of reaction-diffusion fronts
in quasi-two-dimensional periodically-driven fluid flows. These barriers were
called burning invariant manifolds (BIMs). We provide a detailed theoretical
analysis of BIMs, providing criteria for their existence, a classification of
their stability, a formalization of their barrier property, and mechanisms by
which the barriers can be circumvented. This analysis assumes the sharp front
limit and negligible feedback of the front on the fluid velocity. A
low-dimensional dynamical systems analysis provides the core of our results.Comment: 14 pages, 11 figures. To appear in Chaos Focus Issue:
Chemo-Hydrodynamic Patterns and Instabilities (2012
Managers' perceptions towards automation in manufacturing
Based on a survey of managers' perceptions, the major benefits and problems related to the adoption of new automated manufacturing systems have been identified. Variables related to cost justification are perceived to be less important than variables associated with improved flexibility and product quality in influencing a company's intention to raise its level of technological sophistication in the manufacturing area. Problems associated with employee resistance are perceived to be less influential in hampering firms to raise their level of manufacturing automation than variables pertaining to start up, financial justification, and system maintenance. Of several organizational context variables examined, only the type of industry within which the firm functions and the existence of unions in the firm appear to affect managers' perceptions of the benefits of automation. None of these moderating variables seems to influence managers' perceptions of problems related to the adoption of automated manufacturing systems.published_or_final_versio
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