30,336 research outputs found
Prosocial and antisocial children's perceptions of peers' motives for prosocial behaviours
This study investigated whether peer-nominated prosocial and antisocial children have different perceptions of the motives underlying peers' prosocial actions. Eighty-seven children, aged 10-12 years old, completed peer-nomination measures of social behaviour. On the basis of numbers of social nominations received, a subsample of 51 children (32 who were peer-nominated as 'prosocial', and 18 who were peer-nominated as 'antisocial') then recorded their perceptions of peers' motives for prosocial behaviours. Expressed motives were categorized predominantly into three categories, coinciding with Turiel's (1978) 'moral', 'conventional', and 'personal domains'. Results indicate that children's social reputation is associated with the extent to which they perceive peers' prosocial motives as 'personal' or 'moral', with more prosocial children attributing moral motives, and more antisocial children attributing personal motives. Although traditionally Turiel's domain theory has been used to understand 'antisocial' children's behaviour, the current findings suggest that 'prosocial' children's behaviour may also be related to domains of judgment
Human behavioural analysis with self-organizing map for ambient assisted living
This paper presents a system for automatically classifying the resting location of a moving object in an indoor environment. The system uses an unsupervised neural network (Self Organising Feature Map) fully implemented on a low-cost, low-power automated home-based surveillance system, capable of monitoring activity level of elders living alone independently. The proposed system runs on an embedded platform with a specialised ceiling-mounted video sensor for intelligent activity monitoring. The system has the ability to learn resting locations, to measure overall activity levels and to detect specific events such as potential falls. First order motion information, including first order moving average smoothing, is generated from the 2D image coordinates (trajectories). A novel edge-based object detection algorithm capable of running at a reasonable speed on the embedded platform has been developed. The classification is dynamic and achieved in real-time. The dynamic classifier is achieved using a SOFM and a probabilistic model. Experimental results show less than 20% classification error, showing the robustness of our approach over others in literature with minimal power consumption. The head location of the subject is also estimated by a novel approach capable of running on any resource limited platform with power constraints
CARMIL family proteins as multidomain regulators of actin-based motility
CARMILs are large multidomain proteins that regulate the actin-binding activity of capping protein (CP), a major capper of actin filament barbed ends in cells. CARMILs bind directly to CP and induce a conformational change that allosterically decreases but does not abolish its actin-capping activity. The CP-binding domain of CARMIL consists of the CP-interaction (CPI) and CARMIL-specific interaction (CSI) motifs, which are arranged in tandem. Many cellular functions of CARMILs require the interaction with CP; however, a more surprising result is that the cellular function of CP in cells appears to require binding to a CARMIL or another protein with a CPI motif, suggesting that CPI-motif proteins target CP and modulate its actin-capping activity. Vertebrates have three highly conserved genes and expressed isoforms of CARMIL with distinct and overlapping localizations and functions in cells. Various domains of these CARMIL isoforms interact with plasma membranes, vimentin intermediate filaments, SH3-containing class I myosins, the dual-GEF Trio, and other adaptors and signaling molecules. These biochemical properties suggest that CARMILs play a variety of membrane-associated functions related to actin assembly and signaling. CARMIL mutations and variants have been implicated in several human diseases. We focus on roles for CARMILs in signaling in addition to their function as regulators of CP and actin. </jats:p
Unconstrained video monitoring of breathing behavior and application to diagnosis of sleep apnea
This paper presents a new real-time automated infrared video monitoring technique for detection of breathing anomalies, and its application in the diagnosis of obstructive sleep apnea. We introduce a novel motion model to detect subtle, cyclical breathing signals from video, a new 3-D unsupervised self-adaptive breathing template to learn individuals' normal breathing patterns online, and a robust action classification method to recognize abnormal breathing activities and limb movements. This technique avoids imposing positional constraints on the patient, allowing patients to sleep on their back or side, with or without facing the camera, fully or partially occluded by the bed clothes. Moreover, shallow and abdominal breathing patterns do not adversely affect the performance of the method, and it is insensitive to environmental settings such as infrared lighting levels and camera view angles. The experimental results show that the technique achieves high accuracy (94% for the clinical data) in recognizing apnea episodes and body movements and is robust to various occlusion levels, body poses, body movements (i.e., minor head movement, limb movement, body rotation, and slight torso movement), and breathing behavior (e.g., shallow versus heavy breathing, mouth breathing, chest breathing, and abdominal breathing). Ă© 2013 IEEE
Attracted Diffusion-Limited Aggregation
In this paper, we present results of extensive Monte Carlo simulations of
diffusion-limited aggregation (DLA) with a seed placed on an attractive plane
as a simple model in connection with the electrical double layers. We compute
the fractal dimension of the aggregated patterns as a function of the
attraction strength \alpha. For the patterns grown in both two and three
dimensions, the fractal dimension shows a significant dependence on the
attraction strength for small values of \alpha, and approaches to that of the
ordinary two-dimensional (2D) DLA in the limit of large \alpha. For
non-attracting case with \alpha=1, our results in three dimensions reproduce
the patterns of 3D ordinary DLA, while in two dimensions our model leads to
formation of a compact cluster with dimension two. For intermediate \alpha, the
3D clusters have quasi-2D structure with a fractal dimension very close to that
of the ordinary 2D-DLA. This allows one to control morphology of a growing
cluster by tuning a single external parameter \alpha.Comment: 6 pages, 6 figures, to appear in Phys. Rev. E (2012
Characterization of Si/Si_(1-y)C_y superlattices grown by surfactant assisted molecular beam epitaxy
Si/Si_(0.97)C_(0.03) superlattices grown on Si(001) substrates by Sb surfactant assisted molecular beam epitaxy are characterized by in situ reflection high energy electron diffraction (RHEED), atomic force microscopy, transmission electron microscopy (TEM), and high resolution xâray diffraction. The RHEED shows that, in the absence of Sb, the growth front roughens during Si_(0.97)C_(0.03) growth and smooths during subsequent Si growth. In contrast, when Sb is present, the growth front remains smooth throughout the growth. This observation is confirmed by crossâsectional TEM, which reveals that for samples grown without the use of Sb, the Si/Si_(0.97)C_(0.03) interfaces (Si_(0.97)C_(0.03) on Si) are much more abrupt than the Si_(0.97)C_(0.03)/Si interfaces. In the case of Sb assisted growth, there is no observable difference in abruptness between the two types of interfaces. Atomic force microscopy micrographs of the Si_(0.97)C_(0.03) surface reveal features that could be the source of the roughness observed by RHEED and TEM
Sb-surfactant-mediated growth of Si/Si1âyCy superlattices by molecular-beam epitaxy
Si/Si0.97C0.03 superlattices were grown on Si(001) substrates by molecular beam epitaxy (MBE) to study the use of Sb as a surfactant during Si1âyCy growth. In situ reflection high energy electron diffraction (RHEED) shows that while carbon easily disrupts the two-dimensional growth of homoepitaxial Si, such disruption is suppressed for layers grown on Sb-terminated Si(001) surfaces. Cross-sectional transmission electron microscopy (TEM) reveals that for samples grown without the use of Sb, the Si/Si0.97C0.03 interfaces (Si0.97C0.03 on Si) were much more abrupt than Si0.97C0.03/Si interfaces. In the case of Sb-mediated growth, differences in abruptness between the two types of interfaces were not readily observable
Kinetic Theory of Collisionless Self-Gravitating Gases: II. Relativistic Corrections in Galactic Dynamics
In this paper we study the kinetic theory of many-particle astrophysical
systems imposing axial symmetry and extending our previous analysis in Phys.
Rev. D 83, 123007 (2011). Starting from a Newtonian model describing a
collisionless self-gravitating gas, we develop a framework to include
systematically the first general relativistic corrections to the matter
distribution and gravitational potentials for general stationary systems. Then,
we use our method to obtain particular solutions for the case of the Morgan &
Morgan disks. The models obtained are fully analytical and correspond to the
post-Newtonian generalizations of classical ones. We explore some properties of
the models in order to estimate the importance of post-Newtonian corrections
and we find that, contrary to the expectations, the main modifications appear
far from the galaxy cores. As a by-product of this investigation we derive the
corrected version of the tensor virial theorem. For stationary systems we
recover the same result as in the Newtonian theory. However, for time dependent
backgrounds we find that there is an extra piece that contributes to the
variation of the inertia tensor.Comment: 30 pages, 8 figures. v2: Minor corrections and references added.
Conclusions unchanged. v3: Version published in PR
The Stellar and Gas Kinematics of Several Irregular Galaxies
We present long-slit spectra of three irregular galaxies from which we
determinethe stellar kinematics in two of the galaxies (NGC 1156 and NGC 4449)
and ionized-gas kinematics in all three (including NGC 2366). We compare this
to the optical morphology and to the HI kinematics of the galaxies. In the
ionized gas, we see a linear velocity gradient in all three galaxies. In NGC
1156 we also detect a weak linear velocity gradient in the stars of (5+/-1/sin
i) km/s/kpc to a radius of 1.6 kpc. The stars and gas are rotating about the
same axis, but this is different from the major axis of the stellar bar which
dominates the optical light of the galaxy. In NGC 4449 we do not detect
organized rotation of the stars and place an upper limit of (3/sin i) km/s/kpc
to a radius of 1.2 kpc. For NGC 4449, which has signs of a past interaction
with another galaxy, we develop a model to fit the observed kinematics of the
stars and gas. In this model the stellar component is in a rotating disk seen
nearly face-on while the gas is in a tilted disk with orbits whose planes
precess in the gravitational potential. This model reproduces the apparent
counter-rotation of the inner gas of the galaxy. The peculiar orbits of the gas
are presumed due to acquisition of gas in the past interaction.Comment: To be published in ApJ, November 20, 200
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