2,373 research outputs found
Two-Body Density Matrix for Closed s-d Shell Nuclei
The two-body density matrix for and within the
Low-order approximation of the Jastrow correlation method is considered. Closed
analytical expressions for the two-body density matrix, the center of mass and
relative local densities and momentum distributions are presented. The effects
of the short-range correlations on the two-body nuclear characteristics are
investigated.Comment: 13 pages(LaTeX), 4 figures (ps
Enhancement of Tc in the Superconductor-Insulator Phase Transition on Scale-Free Networks
A road map to understand the relation between the onset of the
superconducting state with the particular optimum heterogeneity in granular
superconductors is to study a Random Tranverse Ising Model on complex networks
with a scale-free degree distribution regularized by and exponential cutoff
p(k) \propto k^{-\gamma}\exp[-k/\xi]. In this paper we characterize in detail
the phase diagram of this model and its critical indices both on annealed and
quenched networks. To uncover the phase diagram of the model we use the tools
of heterogeneous mean-field calculations for the annealed networks and the most
advanced techniques of quantum cavity methods for the quenched networks. The
phase diagram of the dynamical process depends on the temperature T, the
coupling constant J and on the value of the branching ratio / where
k is the degree of the nodes in the network. For fixed value of the coupling
the critical temperature increases linearly with the branching ration which
diverges with the increasing cutoff value \xi or value of the \gamma exponent
\gamma< 3. This result suggests that the fractal disorder of the
superconducting material can be responsible for an enhancement of the
superconducting critical temperature. At low temperature and low couplings T<<1
and J<<1, instead, we observe a different behavior for annealed and quenched
networks. In the annealed networks there is no phase transition at zero
temperature while on quenched network we observe a Griffith phase dominated by
extremely rare events and a phase transition at zero temperature. The Griffiths
critical region, nevertheless, is decreasing in size with increasing value of
the cutoff \xi of the degree distribution for values of the \gamma exponents
\gamma< 3.Comment: (17 pages, 3 figures
Advances in surface EMG signal simulation with analytical and numerical descriptions of the volume conductor
Surface electromyographic (EMG) signal modeling is important for signal interpretation, testing of processing algorithms, detection system design, and didactic purposes. Various surface EMG signal models have been proposed in the literature. In this study we focus on 1) the proposal of a method for modeling surface EMG signals by either analytical or numerical descriptions of the volume conductor for space-invariant systems, and 2) the development of advanced models of the volume conductor by numerical approaches, accurately describing not only the volume conductor geometry, as mainly done in the past, but also the conductivity tensor of the muscle tissue. For volume conductors that are space-invariant in the direction of source propagation, the surface potentials generated by any source can be computed by one-dimensional convolutions, once the volume conductor transfer function is derived (analytically or numerically). Conversely, more complex volume conductors require a complete numerical approach. In a numerical approach, the conductivity tensor of the muscle tissue should be matched with the fiber orientation. In some cases (e.g., multi-pinnate muscles) accurate description of the conductivity tensor may be very complex. A method for relating the conductivity tensor of the muscle tissue, to be used in a numerical approach, to the curve describing the muscle fibers is presented and applied to representatively investigate a bi-pinnate muscle with rectilinear and curvilinear fibers. The study thus propose an approach for surface EMG signal simulation in space invariant systems as well as new models of the volume conductor using numerical methods
Addressing learner diversity by promoting flexibility in e-learning environments
E-learning has opened a multitude of possibilities for teaching and learning. As the market matures there is a demand for more effective and cost-efficient learning interventions that meet the learning needs of the diverse learner population. Currently, however, very few teaching attempts have been made to match the pedagogical styles underlying e-learning interventions to students' diverse learning styles. Information and communication technologies can provide a variety of ways for adapting learning environments to students learning styles, although they are not often used to their full potential. In the Global Campus (GC) project at Middlesex University, we studied the differences in the learning styles of our distance and classroom students. We then examined the electronic learning resources and underlying pedagogical approach to establish how effectively they accommodate the diverse learning styles of the students. Finally, we proposed some measures to improve the e-learning environment in a way that matches the students' learning styles more effectively
Automatic Extraction of News Values from Headline Text
Headlines play a crucial role in attracting audiences’ attention to online artefacts (e.g. news articles, videos, blogs). The ability to carry out an automatic, largescale analysis of headlines is critical to facilitate the selection and prioritisation of a large volume of digital content. In journalism studies news content has been extensively studied using manually annotated news values – factors used implicitly and explicitly when making decisions on the selection and prioritisation of news items. This paper presents the first attempt at a fully automatic extraction of news values from headline text. The news values extraction methods are applied on a large headlines corpus collected from The Guardian, and evaluated by comparing it with a manually annotated gold standard. A crowdsourcing survey indicates that news values affect people’s decisions to click on a headline, supporting the need for an automatic news values detection
Reflective Experiential Learning: Using Active Video Watching for Soft Skills Training
Learning by watching videos has become the dominant way of learning for millennials. However, watching videos is a passive form of learning which usually results in a low level of engagement. As the result, video-based learning often results in poor learning outcomes. One of the proven strategies to increase engagement is to integrate interactive activities such as quizzes and assessment problems into videos. Although this strategy increases engagement, it requires changing existing videos and therefore substantial effort from the teacher. We have developed the Active Video Watching (AVW) system that enables the teacher to use existing videos from YouTube without modifications. The teacher is required to define a set of aspects for videos, which serve as reflective scaffolds in order to increase engagement and focus learners’ thinking. AVW provides a Personal Space for individual learners to link their personal experiences while watching videos. The comments collected can be used by the individuals to reflect on their own thoughts or to be shared with other learners in the Social Space. We conducted a study with postgraduate students on presentation skills. The results show that the level of engagement with AVW was high, and that the aspects were effective as reflection prompts. We plan to conduct further studies related to other types of soft skills, and also to further extend AVW to provide individualized feedback to students
Clinical Case of a Child with Optic Neuritis, Associated with Epstein-Barr Virus
We present a clinical case of a child with bilateral papillitis, associated with EBV-infection in a 5-year-old female child, who was diagnosed and treated at the Aleksandrovska University Hospital. The initial reason for the eye-exam was a new-onset squint. On admission, she had discrete Eidon confocal scan, decreased visual acuity and bilateral edema and hyperemia of the optic disks. MRI of brain and orbits was evaluated on emergency to rule out a demyelinating or intracranial process. The child had persistent lymphadenopathy and laboratory abnormalities and tested positive for EBV serology. She was treated with intravenous corticosteroid pulse therapy and visual acuity was restored to 100%. Papillitis in children is frequently bilateral, with viral genesis and has a good prognosis. Isolated papillitis (without inflammation of other eye structures) is difficult to distinguish clinically from papilledema. When papilledema is suspected, urgent MRI has to be carried out
Field testing two animal-specific non-contact thermometers on healthy horses
This study investigated the accuracy of two animal specific non-contact infrared thermometers (Rycom and Thermofocus) when compared to rectal temperature in healthy horses. One hundred rectal and eye temperatures were measured in 22 horses. Fewer than 50% of the readings taken with the Thermofocus device were within ± 0.5°C of rectal temperature. Over 80% of eye temperature readings taken with the Rycom device were within ± 0.5°C of rectal temperature measured from the medial canthus region. The Rycom thermometer also appears to detect hyperthermia when measuring the left eye temperature; however, clinical patient testing is needed before its use can be recommended
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