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51.
This study assessed perception–action coupling in expert swimmers by focusing on their upper limb inter-segmental coordination in front crawl. To characterize this coupling, we manipulated the fluid flow and compared trials performed in a swimming pool and a swimming flume, both at a speed of 1.35 m s−1. The temporal structure of the stroke cycle and the spatial coordination and its variability for both hand/lower arm and lower arm/upper arm couplings of the right body side were analyzed as a function of fluid flow using inertial sensors positioned on the corresponding segments. Swimmers’ perceptions in both environments were assessed using the Borg rating of perceived exertion scale. Results showed that manipulating the swimming environment impacts low-order (e.g., temporal, position, velocity or acceleration parameters) and high-order (i.e., spatial-temporal coordination) variables. The average stroke cycle duration and the relative duration of the catch and glide phases were reduced in the flume trial, which was perceived as very intense, whereas the pull and push phases were longer. Of the four coordination patterns (in-phase, anti-phase, proximal and distal: when the appropriate segment is leading the coordination of the other), flume swimming demonstrated more in-phase coordination for the catch and glide (between hand and lower arm) and recovery (hand/lower arm and lower arm/upper arm couplings). Conversely, the variability of the spatial coordination was not significantly different between the two environments, implying that expert swimmers maintain consistent and stable coordination despite constraints and whatever the swimming resistances. Investigations over a wider range of velocities are needed to better understand coordination dynamics when the aquatic environment is modified by a swimming flume. Since the design of flumes impacts significantly the hydrodynamics and turbulences of the fluid flow, previous results are mainly related to the characteristics of the flume used in the present study (or a similar one), and generalization is subject to additional investigations. 相似文献
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Misteli M Duschek S Richter A Grimm S Rezk M Kraehenmann R Boeker H Seifritz E Schuepbach D 《Brain and cognition》2011,76(1):123-130
Functional Transcranial Doppler sonography (fTCD) has been applied to assess peak mean cerebral blood flow velocity (MFV) with a high temporal resolution during cognitive activation. Yet, little attention has been devoted to gender-related alterations of MFV, including spectral analysis. In healthy subjects, fTCD was used to investigate a series of cerebral hemodynamic parameters in the middle cerebral arteries (MCA) during the Trail Making Tests (TMT), a means of selective attention and complex cognitive functioning. In females, there was a frequency peak at 0.375 Hz in both MCA, and we observed a dynamic shift in hemispheric dominance during that condition. Further, after the start phase, there was an MFV decline during complex functioning for the entire sample. These novel results suggest condition-specific features of cerebral hemodynamics in females, and it adds to the notion that gender is a fundamental confounder of brain physiology. 相似文献
53.
Humans will naturally synchronize their posture to the motion of a visual surround, but it is unclear if this visuomotor entrainment can be attenuated with an increased sensitivity to somatosensory information. Sub-threshold vibratory noise applied to the Achilles tendons has proven to enhance ankle proprioception through the phenomenon of stochastic resonance. Our purpose was to compare visuomotor entrainment during walking and standing, and to understand how this entrainment might be attenuated by applying sub-threshold vibratory noise over the Achilles tendons. We induced visuomotor entrainment during standing and treadmill walking for ten subjects (24.5 ± 2.9 years) using a speed-matched virtual hallway with continuous mediolateral perturbations at three different frequencies. Vibrotactile motors over the Achilles tendons provided noise (0–400 Hz) with an amplitude set to 90% of each participant’s sensory threshold. Mediolateral sacrum, C7, and head motion was greatly amplified (4–8× on average) at the perturbation frequencies during walking, but was much less pronounced during standing. During walking, individuals with greater mediolateral head motion at the fastest perturbation frequency saw the greatest attenuation of that motion with applied noise. Similarly, during standing, individuals who exhibited greater postural sway (as measured by the center of pressure) also saw the greatest reductions in sway with sub-threshold noise applied in three of our summary metrics. Our results suggest that, at least for healthy young adults, sub-threshold vibratory noise over the Achilles tendons can slightly improve postural control during disruptive mediolateral visual perturbations, but the applied noise does not substantially attenuate visuomotor entrainment during walking or standing. 相似文献
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L. Parker Schiffer 《The journal of positive psychology》2018,13(3):252-259
Achieving and maintaining happiness can be difficult, especially when people are not engaging in the activities they know facilitate it. ‘Flow’ activities require clear rules, challenge, a high investment of energy, and have been shown to promote long-term happiness better than low investment, passive activities. Do people know this? In two studies, we found that, despite recognizing that flow activities are more likely to facilitate happiness, people nevertheless participated in passive leisure significantly more often in a typical week. Participants rated passive activities as being significantly more enjoyable, requiring less effort, and being less daunting to get started than flow activities. Participants’ engagement in flow activities was significantly predicted by how enjoyable the activities were perceived to be, whereas how daunting those activities were rated predicted non-engagement. Passive activity engagement was only significantly predicted by enjoyment. Suggestions for enabling people to rise above the barriers to flow activities are offered. 相似文献
56.
Kyeong-Seop Choi 《Journal of the British Society for Phenomenology》2018,49(2):126-138
It is an unprecedented task to interpret Husserl’s transcendental phenomenology as a fundamental philosophy of happiness. Although happiness has been discussed in many psychologies, Csikszentmihalyi’s positive psychology defines happiness as “flow”, a psychic state of ongoing immersion guided by intrinsic motivations and rewards. In this paper, I interpret our transcendental consciousness as a radical “flow” maker and claim that in our transcendental life, happiness is what we ourselves are. Then, I propose this not only as an appeal to a change of attitude (i.e. reduction) for happiness, but also as a deep hermeneutics of the mental skills and activity designs suggested by positive psychology. In this way, worldly happiness dictums can be profoundly re-examined. Understood as such, Husserl’s transcendental phenomenology leaves us the task of how to make a concrete form of qualitative or hermeneutical research on happiness out of it. 相似文献
57.
Andrea S. Camperio Ciani Claudio Capiluppi Antonio Veronese Giuseppe Sartori 《欧洲人格杂志》2007,21(1):3-22
Whether differences in personality among populations really exist and, if so, whether they are only due to cultural and linguistic differences or have a genetically selected adaptive value, is a controversial issue. In this research, we compared three Italian populations living on three small archipelagos in the Tyrrhenian Sea (n = 993), with their corresponding neighbouring mainlanders (n = 598), i.e. sharing the same geographical origin, culture and language. We used an adjective‐based Big Five questionnaire in order to measure personality traits in four categories of individuals for each archipelago/mainland population: (1) original islanders; (2) non‐original islanders; (3) mainlanders and (4) immigrants to the islands. We further analysed original and non‐original islanders who had or had not emigrated from the islands. We found that islanders had different personality traits from mainlanders, the former being more conscientious and emotionally stable and less extraverted and open to experience. We also found that the subgroup of islanders whose ancestors had inhabited their island for about 20 generations in isolation (original islanders, n = 624) were less extraverted and open to experience than immigrants (n = 193). In contrast, immigrants retained the typical personality profile of the mainland populations. Lastly, emigrants from the islands (n = 209) were significantly more extraverted and open to experience than original and non‐original islanders who had never left their island (n = 741). We hypothesise that population differences in extraversion and openness to experience are more probably related to genetic differences which evolved rapidly, presumably through an active gene flow produced by selective emigration from the islands. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
58.
The multi-agent-systems paradigm is becoming more and more popular as a basis for realizing net-based solutions. This development is accompanied by an increasing relevance of security issues. For instance, the potential loss of privacy and other assets is a major concern for, both merchants and customers, in Internet-based commerce and, without being properly addressed, such very legitimate concerns hamper the growth of e-commerce.This article uses a comparison-shopping scenario to introduce a general methodology for formally verifying the security of multi-agent systems. Following the approach of possibilistic information flow security, the flow of information between and within agents is restricted in order to ensure that secrets will not be disclosed to unauthorized meddlers. The security requirements for the overall system are then decomposed into requirements for the individual agents that can be verified independently from each other. Exploiting the modular structure of a multi-agent system considerably reduces the complexity of the overall security analysis. The techniques for decomposing security requirements, for verifying individual agents, and for deriving global security guarantees for the entire system from locally verified properties are all generic in the sense that they apply also to many other systems and security requirements than the ones that appear in the example scenario. 相似文献
59.
赵晓华 《医学与哲学(人文社会医学版)》2009,30(3):36-38
为探讨骨髓增生异常综合征患者与再生障碍性贫血患者骨髓髓系细胞的免疫表型变化,用流式细胞术检测骨髓增生异常综合征、再生障碍性贫血及正常对照髓系细胞的表面抗原。结果显示骨髓增生异常综合征组髓系细胞较正常对照组及再生障碍性贫血组表面抗原表达明显不同。因此,流式细胞术有助于二者的诊断及鉴别诊断。 相似文献
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This study examined the psychometric properties of the Dispositional Flow Scale-2 (DFS-2; Jackson and Eklund in Journal of
Sports and Exercise Psychology, 24:133-150, 2002). One thousand five hundred and seventy-eight secondary school students (One thousand and seventy four males, four hundred
and eleven females, ninety-three missing) from six schools in Singapore completed the questionnaires. Confirmatory factor
analysis (CFA) was used to evaluate the factorial structure of the DFS-2. A nine-first-order factor model was compared to
a higher order model with a global flow factor. Support was found for the higher order factor. Multigroup analysis demonstrated
invariance of the factor forms, factor loadings, factor variances, and factor covariances across age and sex. The DFS-2 subscales
were found to have acceptable reliability estimates, and convergent validity. We conclude that DFS-2 is a valid instrument
for assessing global flow experience in Internet gaming. 相似文献