18,069 research outputs found
Figurative elements in mosaics and roman painting at Algarve (Portugal)
The figurative mosaics with marine fauna at Algarve region, in the south of Portugal, are various and well known, particularly from Roman villa of Milreu. But connected to the sea there are also human representations in the mosaics of the region which, such as the marine themes, are characterized by a strong stylistic link to the Roman art of the North Africa. Recently both figurative themes, animal or human, also arise in parietal painting of the Algarve, specifically in a maritime villa specialized in fish-salting with strong North African links well attested by pottery import profile. This paper aims to explore affinities with both types of artistic representations in the region south of the former province of Lusitania, as well as to see North African links
Monte Carlo Simulations of Sexual Reproduction
Modifying the Redfield model of sexual reproduction and the Penna model of
biological aging, we compare reproduction with and without recombination in
age-structured populations. In contrast to Redfield and in agreement with
Bernardes we find sexual reproduction to be preferred to asexual one. In
particular, the presence of old but still reproducing males helps the survival
of younger females beyond their reproductive age.Comment: 8 pages, plain tex, 7 EPS figures, to appear in PHYSICA
Election results and the Sznajd model on Barabasi network
The network of Barabasi and Albert, a preferential growth model where a new
node is linked to the old ones with a probability proportional to their
connectivity, is applied to Brazilian election results. The application of the
Sznajd rule, that only agreeing pairs of people can convince their neighbours,
gives a vote distribution in good agreement with reality.Comment: 7 pages including two figures, for Eur. Phys. J.
Why and when social support predicts older adults’ pain-related disability
Pain-related social support has been shown to be directly associated with pain-related disability, depending on whether it promotes functional autonomy or dependence. However, previous studies mostly relied on cross-sectional methods, precluding conclusions on the temporal relationship between pain-related social support and disability. Also, research on the behavioral and psychological processes that account for such a relationship is scarce. Therefore, this study aimed at investigating the following longitudinally: (1) direct effects of social support for functional autonomy/dependence on pain-related disability, (2) mediating role of physical functioning, pain-related self-efficacy, and fear, and (3) whether pain duration and pain intensity moderate such mediating processes. A total of 168 older adults (Mage = 78.3; SDage = 8.7) participated in a 3-month prospective design, with 3 moments of measurement, with a 6-week lag between them. Participants completed the Formal Social Support for Autonomy and Dependence in Pain Inventory, the Brief Pain Inventory, the 36-SF Health Survey, behavioral tasks from the Senior Fitness Test, the Pain Self-Efficacy Questionnaire, and the Tampa Scale for Kinesiophobia. Moderated mediation analyses showed that formal social support for functional dependence (T1) predicted an increase in pain-related disability (T3), that was mediated by self-reported physical functioning (T2) and by pain-related self-efficacy (T2) at short to moderate pain duration and at low to moderate pain intensity, but not at higher levels. Findings emphasized that social support for functional dependence is a risk factor for pain-related disability and uncovered the “why” and “when” of this relationship. Implications for the design of social support interventions aiming at promoting older adults' healthy aging despite chronic pain are drawn.info:eu-repo/semantics/acceptedVersio
Ripples and Grains Segregation on Unpaved Road
Ripples or corrugations are common phenomena observed in unpaved roads in
less developed countries or regions. They cause several damages in vehicles
leading to increased maintenance and product costs. In this paper, we present a
computational study about the so-called washboard roads. Also, we study grain
segregation on unpaved roads. Our simulations have been performed by the
Discrete Element Method (DEM). In our model, the grains are regarded as soft
disks. The grains are subjected to a gravitational field and both translational
and rotational movements are allowed. The results show that wheels' of
different sizes, weights and moving with different velocities can change
corrugations amplitude and wavelength. Our results also show that some
wavelength values are related to specific wheels' speed intervals. Segregation
has been studied in roads formed by three distinct grain diameters
distribution. We observed that the phenomenon is more evident for higher grain
size dispersion
On the Dynamics of Induced Maps on the Space of Probability Measures
For the generic continuous map and for the generic homeomorphism of the
Cantor space, we study the dynamics of the induced map on the space of
probability measures, with emphasis on the notions of Li-Yorke chaos,
topological entropy, equicontinuity, chain continuity, chain mixing, shadowing
and recurrence. We also establish some results concerning induced maps that
hold on arbitrary compact metric spaces.Comment: 23 page
Mean Li-Yorke chaos in Banach spaces
We investigate the notion of mean Li-Yorke chaos for operators on Banach
spaces. We show that it differs from the notion of distributional chaos of type
2, contrary to what happens in the context of topological dynamics on compact
metric spaces. We prove that an operator is mean Li-Yorke chaotic if and only
if it has an absolutely mean irregular vector. As a consequence, absolutely
Ces\`aro bounded operators are never mean Li-Yorke chaotic. Dense mean Li-Yorke
chaos is shown to be equivalent to the existence of a dense (or residual) set
of absolutely mean irregular vectors. As a consequence, every mean Li-Yorke
chaotic operator is densely mean Li-Yorke chaotic on some infinite-dimensional
closed invariant subspace. A (Dense) Mean Li-Yorke Chaos Criterion and a
sufficient condition for the existence of a dense absolutely mean irregular
manifold are also obtained. Moreover, we construct an example of an invertible
hypercyclic operator such that every nonzero vector is absolutely mean
irregular for both and . Several other examples are also presented.
Finally, mean Li-Yorke chaos is also investigated for -semigroups of
operators on Banach spaces.Comment: 26 page
Li-Yorke Chaos for Composition Operators on -Spaces
Li-Yorke chaos is a popular and well-studied notion of chaos. Several simple
and useful characterizations of this notion of chaos in the setting of linear
dynamics were obtained recently. In this note we show that even simpler and
more useful characterizations of Li-Yorke chaos can be given in the special
setting of composition operators on spaces. As a consequence we obtain a
simple characterization of weighted shifts which are Li-Yorke chaotic. We give
numerous examples to show that our results are sharp
Buffer or amplifier? Longitudinal effects of social support for functional autonomy/dependence on older adults’ chronic-pain experiences
Objective: This longitudinal study aimed to investigate (a) the moderating role of formal social support for functional autonomy versus dependence on the relationship between pain intensity and pain-related disability among older adults with chronic pain and (b) the mediating role of pain-related self-efficacy and pain-related fear in this moderation. Method: One hundred and seventy older adults (Mage = 78.0; SD = 8.7) with chronic musculoskeletal pain participated in a 3-month prospective study, with 3 measurement moments. Participants filled out the Formal Social Support for Autonomy and Dependence in Pain Inventory, the Portuguese versions of the Brief Pain Inventory, the Pain Self-Efficacy Questionnaire, and the Tampa Scale of Kinesiophobia. Results: Using structural equation modeling, it was found that perceived promotion of autonomy, at Time 1, moderated the relationship between pain intensity (T1) and pain-related disability (T2); this moderation was fully mediated by pain-related self-efficacy (T2). Perceived promotion of dependence was not a significant moderator. Conclusions: These findings highlight the importance of social support for functional autonomy in buffering the impact of pain intensity on older adults’ pain-related disability. Also, they clarify the role of pain-related self-efficacy in this effect. Implications for the development of intervention programs, with formal caregivers, to reduce the impact of chronic pain on older adults’ healthy ageing process, are discussed.info:eu-repo/semantics/acceptedVersio
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