Muscle Function and Fatigability of Trunk Flexors in Males and Females

Background Optimal function of the abdominal muscles is necessary for several life functions including lifting and carrying tasks. Sex differences in strength and fatigability are established for many limb muscles and back extensor muscles, but it is unknown if sex differences exist for the abdominal muscles despite their functional importance. Methods Eighteen females (24.3 ± 4.8 years) and 15 males (24.1 ± 6.6 years) performed (1) isometric trunk flexion maximal voluntary contractions (MVCs) in a range of trunk positions to establish a torque-angle curve and (2) submaximal (50% MVC), intermittent isometric contraction (6 s on, 4 s off) until task failure to determine fatigability of the trunk flexor muscles. Dual X-ray absorptiometry quantified body fat and lean mass. Physical activity levels were quantified with a questionnaire. Torque-angle curves, electromyography (EMG), MVC torque, and torque steadiness were compared with repeated measures ANOVA with sex as a between-subjects factor. Results For the torque-angle curve, MVC torque was reduced as the trunk angle increased toward flexion (p \u3c 0.001). Males had greater MVC torque than females at the extended positions (31% difference), with no sex differences in torque in upright sitting (p \u3e 0.05). Time-to-task failure for the submaximal fatigability task in upright sitting was similar between males and females (12.4 ± 7 vs 10.5 ± 6 min). Time-to-task failure was positively associated with strength (r = 0.473, p = 0.005) and self-reported physical activity (r = 0.456, p = 0.030). Lean mass in the trunk was positively associated with trunk flexor strength (r = 0.378, p = 0.011) and self-reported physical activity (r = 0.486, p = 0.007). Finally, torque steadiness [coefficient of variation of torque (CV)] during submaximal isometric contractions decreased with contraction intensity and was similar for males and females across all intensities. Conclusions Unlike many limb muscle groups, males and females had similar fatigability and torque steadiness of the trunk flexor muscles during isometric contractions. Stronger individuals, however, exhibited less fatigability. Lower self-reported physical activity was associated with greater fatigability of trunk flexor muscles. The relationship between strength and fatigability of the trunk flexor muscles and physical activity supports the importance of abdominal muscle strengthening to offset fatigability in both males and females

End-user Empowerment: An Interdisciplinary Perspective

In virtue of fast spreading emerging technologies, considering end-user empowerment (or human empowerment) while developing or adapting technologies gains importance. Even though many different approaches to end-user empowerment have been proposed, it is hardly clear what end-user (human) empowerment is and how it is possible to develop end-user empowering systems . This paper offers an interdisciplinary perspective on how it can be possible to arrive at a synthesized concept of end-user empowerment, in particular regarding the development of Information and Communication Technologies (ICTs). The provided interdisciplinary perspective includes concepts from Computer Science, Information Systems, Cognitive Science, Psychology, Sociology, Science-Technology-Society, Design, System Science and Philosophy. Based on an interdisciplinary literature review, and from an enactivist, pluralist, and constructivist perspective, we argue that the individual end-users and their needs and values, as well as the environment (including socioeconomical contexts, other actors, etc.) and technologies they interact with, continuously co-create the conception of end-user empowerment. Moreover, we propose that perceiving technological development as co-creation, and considering technologies as value-bearers could provide the first steps in the development of conceptual frameworks required for the development of end-user empowering systems

Fatigability of the Lumbopelvic Stabilizing Muscles in Women 8 and 26 Weeks Postpartum

Background: Pregnancy and childbirth are associated with lumbopelvic pain and instability. Fatigability of the lumbopelvic stabilizing muscles after childbirth is unknown, and no clinical tests exist to assess this important metric of muscle function. Objectives: To compare fatigability of the lumbopelvic stabilizing muscles in postpartum and nulligravid (control) women using the Active Straight Leg Raise (ASLR) Fatigue Task, and to determine whether fatigability is associated with interrecti distance (IRD), physical function, and pain/disability. Study design: A longitudinal case-control study. Methods: Twenty-nine nulligravid (25.4 +/- 9.1 years) and 31 postpartum women (31.4 +/- 5.2 years; vaginal delivery n = 18) were tested at 2 time points, 16 weeks apart (postpartum women tested at 8-10 and 24-26 weeks postpartum). Muscular function was assessed with manual muscle testing (MMT), the ASLR test, and a new ASLR Fatigue Task. Other measures included IRD, rectus abdominis thickness, physical activity, and 6-minute walk distance. Results: Postpartum women were 23% more fatigable (P = .028) and were weaker (MMT) (P \u3c .001) than controls up to 26 weeks postpartum. The ASLR Fatigue Task (time-to-failure) was associated with smaller IRD, greater rectus abdominis thickness, higher physical activity levels, greater MMT strength, and further distance walked in 6 minutes (P \u3c .05). Conclusion: Postpartum women (up to 6 months) had greater fatigability of the lumbopelvic stabilizing muscles and lower physical function than nulligravid women, suggesting core muscle function and fatigability should be assessed after pregnancy and childbirth. The ASLR Fatigue Task could be a clinically useful tool to determine fatigability of the lumbopelvic stabilizing muscles in women postpartum

Growth laws and self-similar growth regimes of coarsening two-dimensional foams: Transition from dry to wet limits

We study the topology and geometry of two dimensional coarsening foams with arbitrary liquid fraction. To interpolate between the dry limit described by von Neumann's law, and the wet limit described by Marqusee equation, the relevant bubble characteristics are the Plateau border radius and a new variable, the effective number of sides. We propose an equation for the individual bubble growth rate as the weighted sum of the growth through bubble-bubble interfaces and through bubble-Plateau borders interfaces. The resulting prediction is successfully tested, without adjustable parameter, using extensive bidimensional Potts model simulations. Simulations also show that a selfsimilar growth regime is observed at any liquid fraction and determine how the average size growth exponent, side number distribution and relative size distribution interpolate between the extreme limits. Applications include concentrated emulsions, grains in polycrystals and other domains with coarsening driven by curvature

Chandra Observations of the X-Ray Jet of 3C273

We report results from Chandra observations of the X-ray jet of 3C~273 during the calibration phase in 2000 January. The zeroeth-order images and spectra from two 40-ks exposures with the HETG and LETG+ACIS-S show a complex X-ray structure. The brightest optical knots are detected and resolved in the 0.2-8 keV energy band. The X-ray morphology tracks well the optical. However, while the X-ray brightness decreases along the jet, the outer parts of the jet tend to be increasingly bright with increasing wavelength. The spectral energy distributions of four selected regions can best be explained by inverse Compton scattering of (beamed) cosmic microwave background photons. The model parameters are compatible with equipartition and a moderate Doppler factor, which is consistent with the one-sidedness of the jet. Alternative models either imply implausible physical conditions and energetics (the synchrotron self-Compton model) or are sufficiently ad hoc to be unconstrained by the present data (synchrotron radiation from a spatially or temporally distinct particle population).Comment: 3 figures; Figure 1 in color. Accepted for publication by ApJ Letter

Apresentação : a Guerra do Paraguai na literatura

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Analysis of Resilience and its Relationships with Psychological Factors during Successful Aging

The objective of this research was to verify the relationship between resilience, successful aging, wisdom, quality of life, basic psychological needs perception, cognition and depression. The methodological design was quantitative and transversal. 161 elderly people of both sexes living in the city of Ivoti / Brazil participated. The instruments used were the Resilience Scale, Wisdom Scale, Geriatric Depression Scale, and Inventory of Basic Psychological Needs Perceptions for the Elderly, MMSE, and Whoqol-Old. Spearman's correlation analysis identified the relationship between resilience and quality of life variables, basic psychological needs and depression. In the linear regression analysis, we found a model in which the increase of resilience is associated to the personal competence, autonomy, wisdom, cognitive performance and past, present and future activities. We conclude that the resilience association with psychological aspects in the onset of old age is an important protective factor for the maintenance of successful aging

Alzheimer's disease: using gene/protein network machine learning for molecule discovery in olive oil

Alzheimer's disease (AD) poses a profound human, social, and economic burden. Previous studies suggest that extra virgin olive oil (EVOO) may be helpful in preventing cognitive decline. Here, we present a network machine learning method for identifying bioactive phytochemicals in EVOO with the highest potential to impact the protein network linked to the development and progression of the AD. A balanced classification accuracy of 70.3 ± 2.6% was achieved in fivefold cross-validation settings for predicting late-stage experimental drugs targeting AD from other clinically approved drugs. The calibrated machine learning algorithm was then used to predict the likelihood of existing drugs and known EVOO phytochemicals to be similar in action to the drugs impacting AD protein networks. These analyses identified the following ten EVOO phytochemicals with the highest likelihood of being active against AD: quercetin, genistein, luteolin, palmitoleate, stearic acid, apigenin, epicatechin, kaempferol, squalene, and daidzein (in the order from the highest to the lowest likelihood). This in silico study presents a framework that brings together artificial intelligence, analytical chemistry, and omics studies to identify unique therapeutic agents. It provides new insights into how EVOO constituents may help treat or prevent AD and potentially provide a basis for consideration in future clinical studies

Dissipation and spontaneous symmetry breaking in brain dynamics

We compare the predictions of the dissipative quantum model of brain with neurophysiological data collected from electroencephalograms resulting from high-density arrays fixed on the surfaces of primary sensory and limbic areas of trained rabbits and cats. Functional brain imaging in relation to behavior reveals the formation of coherent domains of synchronized neuronal oscillatory activity and phase transitions predicted by the dissipative model.Comment: Restyled, slight changes in title and abstract, updated bibliography, J. Phys. A: Math. Theor. Vol. 41 (2008) in prin