604 research outputs found
Three Kinds or Grades of Phantasia in Aristotle’s De Anima
Phantasia / imagination in Aristotle is one of the parts or faculties / powers of the soul that cannot exist apart from sensation and thought. The function of phantasia and its connection with phantasmata, the products of this faculty, plays a significant role in the psychological treatises of the Aristotelian Corpus. The purpose of this paper is to examine the concept of phantasia in Book III, Chapter 3 of De Anima, and to show that the Stagyrite philosopher distinguishes three and not two kinds of phantasia, starting from the lowest, which is found in imperfect creatures, to the highest, which appears only in the human beings.Phantasia / imagination in Aristotle is one of the parts or faculties / powers of the soul that cannot exist apart from sensation and thought. The function of phantasia and its connection with phantasmata, the products of this faculty, plays a significant role in the psychological treatises of the Aristotelian Corpus. The purpose of this paper is to examine the concept of phantasia in Book III, Chapter 3 of De Anima, and to show that the Stagyrite philosopher distinguishes three and not two kinds of phantasia, starting from the lowest, which is found in imperfect creatures, to the highest, which appears only in the human beings
Quantum versus Classical Dynamics in a driven barrier: the role of kinematic effects
We study the dynamics of the classical and quantum mechanical scattering of a
wave packet from an oscillating barrier. Our main focus is on the dependence of
the transmission coefficient on the initial energy of the wave packet for a
wide range of oscillation frequencies. The behavior of the quantum transmission
coefficient is affected by tunneling phenomena, resonances and kinematic
effects emanating from the time dependence of the potential. We show that when
kinematic effects dominate (mainly in intermediate frequencies), classical
mechanics provides very good approximation of quantum results. Moreover, in the
frequency region of optimal agreement between classical and quantum
transmission coefficient, the transmission threshold, i.e. the energy above
which the transmission coefficient becomes larger than a specific small
threshold value, is found to exhibit a minimum. We also consider the form of
the transmitted wave packet and we find that for low values of the frequency
the incoming classical and quantum wave packet can be split into a train of
well separated coherent pulses, a phenomenon which can admit purely classical
kinematic interpretation
Human-centered 2D/3D Video Content Analysis and Description
In this paper, we propose a way of using the AudioVisual Description Profile (AVDP) of the MPEG-7 standard for stereo video and multichannel audio content description. Our aim is to provide means of using AVDP in such a way, that 3D video and audio content can be correctly and consistently described. Since AVDP semantics do not include ways for dealing with 3D audiovisual content, a new semantic framework within AVDP is proposed and examples of using AVDP to describe the results of analysis algorithms on stereo video and multichannel audio content are presented
Hyperacceleration in a stochastic Fermi-Ulam model
Fermi acceleration in a Fermi-Ulam model, consisting of an ensemble of
particles bouncing between two, infinitely heavy, stochastically oscillating
hard walls, is investigated. It is shown that the widely used approximation,
neglecting the displacement of the walls (static wall approximation), leads to
a systematic underestimation of particle acceleration. An improved
approximative map is introduced, which takes into account the effect of the
wall displacement, and in addition allows the analytical estimation of the long
term behavior of the particle mean velocity as well as the corresponding
probability distribution, in complete agreement with the numerical results of
the exact dynamics. This effect accounting for the increased particle
acceleration -Fermi hyperacceleration- is also present in higher dimensional
systems, such as the driven Lorentz gas.Comment: 4 pages, 3 figures. To be published in Phys. Rev. Let
Ability of Self-Reported Frailty Components to Predict Incident Disability, Falls, and All-Cause Mortality: Results From a Population-Based Study of Older British Men.
BACKGROUND: Frailty is a state of increased vulnerability to disability, falls, and mortality. The Fried frailty phenotype includes assessments of grip strength and gait speed, which are complex or require objective measurements and are challenging in routine primary care practice. In this study, we aimed to develop a simple assessment tool based on self-reported information on the 5 Fried frailty components to identify older people at risk of incident disability, falls, and mortality. METHODS: Analyses are based on a prospective cohort comprising older British men aged 71-92 years in 2010-2012. A follow-up questionnaire was completed in 2014. The discriminatory power for incident disability and falls was compared with the Fried frailty phenotype using receiver operating characteristic-area under the curve (ROC-AUC); for incident falls it was additionally compared with the FRAIL scale (fatigue, resistance, ambulation, illnesses, and loss of weight). Predictive ability for mortality was assessed using age-adjusted Cox proportional hazard models. RESULTS: A model including self-reported measures of slow walking speed, low physical activity, and exhaustion had a significantly increased ROC-AUC [0.68, 95% confidence interval (CI) 0.63-0.72] for incident disability compared with the Fried frailty phenotype (0.63, 95% CI 0.59-0.68; P value of ΔAUC = .003). A second model including self-reported measures of slow walking speed, low physical activity, and weight loss had a higher ROC-AUC (0.64, 95% CI 0.59-0.68) for incident falls compared with the Fried frailty phenotype (0.57, 95% CI 0.53-0.61; P value of ΔAUC < .001) and the FRAIL scale (0.56, 95% CI 0.52-0.61; P value of ΔAUC = .001). This model was also associated with an increased risk of mortality (Harrell's C = 0.73, Somer's D = 0.45; linear trend P < .001) compared with the Fried phenotype (Harrell's C = 0.71; Somer's D = 0.42; linear trend P < .001) and the FRAIL scale (Harrell's C = 0.71, Somer's D = 0.42; linear trend P < .001). CONCLUSIONS: Self-reported information on the Fried frailty components had superior discriminatory and predictive ability compared with the Fried frailty phenotype for all the adverse outcomes considered and with the FRAIL scale for incident falls and mortality. These findings have important implications for developing interventions and health care policies as they offer a simple way to identify older people at risk of adverse outcomes associated with frailty
The relationships between body composition characteristics and cognitive functioning in a population-based sample of older British men.
BACKGROUND: Current research has established obesity as one of the main modifiable risk factors for cognitive impairment. However, evidence on the relationships of total and regional body composition measures as well as sarcopenia with cognitive functioning in the older population remains inconsistent. METHODS: Data are based on 1,570 participants from the British Regional Heart Study (BRHS), a cohort of older British men from 24 British towns initiated in 1978-80, who were re-examined in 2010-12, aged 71-92 years. Cognitive functioning was assessed with the Test-Your-Memory cognitive screening tool. Body composition characteristics assessed using bioelectrical impedance analysis included total fat mass (FM), central FM, peripheral FM, and visceral fat level. Sarcopenia was defined using the European Working Group on Sarcopenia in Older People (EWGSOP) definition of severe sarcopenia and the Foundation for the National Institutes of Health (FNIH) sarcopenia project criteria. RESULTS: Among 1,570 men, 636 (41 %) were classified in the mild cognitive impairment (MCI) and 133 (8 %) in the severe cognitive impairment (SCI) groups. Age-adjusted multinomial logistic regressions showed that compared with participants in the normal cognitive ageing group, those with SCI were more likely to have waist circumference >102 cm, BMI >30 kg/m(2), to be in the upper quintile of total FM, central FM, peripheral FM and visceral fat level and to be sarcopenic. The relationships remained significant for total FM (RR = 2.16, 95 % CI 1.29-3.63), central FM (RR = 1.85, 95 % CI 1.09-3.14), peripheral FM (RR = 2.67, 95 % CI 1.59-4.48), visceral fat level (RR = 2.28, 95 % CI 1.32-3.94), BMI (RR = 2.25, 95 % CI 1.36-3.72) and waist circumference (RR = 1.63, 95 % CI 1.05-2.55) after adjustments for alcohol, smoking, social class, physical activity and history of cardiovascular diseases or diabetes. After further adjustments for interleukin-6 and insulin resistance, central FM, waist circumference and sarcopenia were no longer significantly associated with SCI. CONCLUSIONS: Increased levels of peripheral FM, visceral fat level, and BMI are associated with SCI among older people. Distinct pathophysiological mechanisms link regional adipose tissue deposition and cognitive functioning
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