2,534 research outputs found
Multimedia courseware: Never mind the quality how much will it cost to develop?
This paper evaluates multimedia courseware costing techniques such as the US Airforce Interactive Courseware Method (Golas, 1993), CBT Analyst (Kearsley, 1985), CEAC (Schooley, 1988) and MEEM (Marshall, Samson, Dugard, & Scott, 1994) against the data from ten multimedia courseware developments. The Relative Error and Mean Absolute Relative Error (MARE) are calculated to allow comparison of the different methods
Unsupervised Segmentation of Action Segments in Egocentric Videos using Gaze
Unsupervised segmentation of action segments in egocentric videos is a
desirable feature in tasks such as activity recognition and content-based video
retrieval. Reducing the search space into a finite set of action segments
facilitates a faster and less noisy matching. However, there exist a
substantial gap in machine understanding of natural temporal cuts during a
continuous human activity. This work reports on a novel gaze-based approach for
segmenting action segments in videos captured using an egocentric camera. Gaze
is used to locate the region-of-interest inside a frame. By tracking two simple
motion-based parameters inside successive regions-of-interest, we discover a
finite set of temporal cuts. We present several results using combinations (of
the two parameters) on a dataset, i.e., BRISGAZE-ACTIONS. The dataset contains
egocentric videos depicting several daily-living activities. The quality of the
temporal cuts is further improved by implementing two entropy measures.Comment: To appear in 2017 IEEE International Conference On Signal and Image
Processing Application
Chronic Oral Capsaicin Exposure During Development Leads to Adult Rats with Reduced Taste Bud Volumes
Introduction A cross-sensory interaction between gustatory and trigeminal nerves occurs in the anterior tongue. Surgical manipulations have demonstrated that the strength of this relationship varies across development. Capsaicin is a neurotoxin that affects fibers of the somatosensory lingual nerve surrounding taste buds, but not fibers of the gustatory chorda tympani nerve which synapse with taste receptor cells. Since capsaicin is commonly consumed by many species, including humans, the experimental use of this neurotoxin provides a naturalistic perturbation of the lingual trigeminal system. Neonatal or adult rats consumed oral capsaicin for 40 days, and we examined the cross-sensory effect on the morphology of taste buds across development. Methods Rats received moderate doses of oral capsaicin, with chronic treatments occurring either before or after taste system maturation. Tongue morphology was examined either 2 or 50 days after treatment cessation. Edema, which has been previously suggested as a cause of changes in capsaicin-related gustatory function, was also assessed. Results Reductions in taste bud volume occurred 50 days, but not 2 days post-treatment for rats treated as neonates. Adult rats at either time post-treatment were unaffected. Edema was not found to occur with the 5 ppm concentration of capsaicin we used. Conclusions Results further elucidate the cooperative relationship between these discrete sensory systems and highlight the developmentally mediated aspect of this interaction. Implications Chronic exposure to even moderate levels of noxious stimuli during development has the ability to impact the orosensory environment, and these changes may not be evident until long after exposure has ceased
Needle age-related and seasonal photosynthetic capacity variation is negligible for modelling yearly gas exchange of a sparse temperate Scots pine forest
In this study, we quantified the predictive accuracy loss involved with
omitting photosynthetic capacity variation for a Scots pine (<i>Pinus sylvestris</i> L.) stand in
Flanders, Belgium. Over the course of one phenological year, we measured the
maximum carboxylation capacity at 25 °C (<i>V</i><sub>m25</sub>), the maximum electron
transport capacity at 25 °C (<i>J</i><sub>m25</sub>), and the leaf area index (LAI) of
different-aged needle cohorts in the upper and lower canopy. We used these
measurements as input for a process-based multi-layer canopy model with the
objective to quantify the difference in yearly gross ecosystem productivity
(GEP) and canopy transpiration (<i>E</i><sub>can</sub>) simulated under scenarios in which
the observed needle age-related and/or seasonal variation of <i>V</i><sub>m25</sub> and
<i>J</i><sub>m25</sub> was omitted. We compared simulated GEP with estimations obtained from
eddy covariance measurements. Additionally, we measured summer needle N
content to investigate the relationship between photosynthetic capacity
parameters and needle N content along different needle ages.
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Results show that <i>V</i><sub>m25</sub> and <i>J</i><sub>m25</sub> were, respectively, 27% and
13% higher in current-year than in one-year old needles. A significant
seasonality effect was found on <i>V</i><sub>m25</sub>, but not on <i>J</i><sub>m25</sub>. Summer needle
N content was considerably lower in current-year than in one-year-old
needles. As a result, the correlations between <i>V</i><sub>m25</sub> and needle N content
and <i>J</i><sub>m25</sub> and needle N content were negative and non-significant,
respectively. Some explanations for these unexpected correlations were
brought forward. Yearly GEP was overestimated by the canopy model by ±15% under all scenarios. The inclusion and omission of the observed
needle age-related <i>V</i><sub>m25</sub> and <i>J</i><sub>m25</sub> variation in the model simulations
led to statistically significant but ecologically irrelevant differences in
simulated yearly GEP and <i>E</i><sub>can</sub>. Omitting seasonal variation did not yield
significant simulation differences. Our results indicate that intensive
photosynthetic capacity measurements over the full growing season and
separate simulation of needle age classes were no prerequisites for accurate
simulations of yearly canopy gas exchange. This is true, at least, for the
studied stand, which has a very sparse canopy and is exposed to high N
deposition and, hence, is not fully representative for temperate Scots pine
stands. Nevertheless, we believe well-parameterized process-based canopy
models – as applied in this study – are a useful tool to quantify losses of
predictive accuracy involved with canopy simplification in modelling
Observation of vortex dipoles in an oblate Bose-Einstein condensate
We report experimental observations and numerical simulations of the
formation, dynamics, and lifetimes of single and multiply charged quantized
vortex dipoles in highly oblate dilute-gas Bose-Einstein condensates (BECs). We
nucleate pairs of vortices of opposite charge (vortex dipoles) by forcing
superfluid flow around a repulsive gaussian obstacle within the BEC. By
controlling the flow velocity we determine the critical velocity for the
nucleation of a single vortex dipole, with excellent agreement between
experimental and numerical results. We present measurements of vortex dipole
dynamics, finding that the vortex cores of opposite charge can exist for many
seconds and that annihilation is inhibited in our highly oblate trap geometry.
For sufficiently rapid flow velocities we find that clusters of like-charge
vortices aggregate into long-lived dipolar flow structures.Comment: 4 pages, 4 figures, 1 EPAPS fil
Superconductivity in a Hubbard-Froehlich Model and in cuprates
Using the variational Monte-Carlo method we find that a relatively weak
long-range electron-phonon interaction induces a d-wave superconducting state
of doped Mott-Hubbard insulators and/or strongly-correlated metals with a
condensation energy significantly larger than can be obtained with Coulomb
repulsion only. Moreover, the superconductivity is shown to exist for infinite
on-site Coulomb repulsion, removing the requirement for additional mechanisms
such as spin fluctuations to mediate d-wave superconductivity. We argue that
the superconducting state is robust with respect to a more intricate choice of
the trial function and that the true origin of high-temperature
superconductivity lies in a proper combination of strong electron-electron
correlations with poorly screened Froehlich electron-phonon interaction.Comment: 4 pages, 4 figure
Neural Circuitry of Novelty Salience Processing in Psychosis Risk: Association With Clinical Outcome
Psychosis has been proposed to develop from dysfunction in a hippocampal-striatal-midbrain circuit, leading to aberrant salience processing. Here, we used functional magnetic resonance imaging (fMRI) during novelty salience processing to investigate this model in people at clinical high risk (CHR) for psychosis according to their subsequent clinical outcomes. Seventy-six CHR participants as defined using the Comprehensive Assessment of At-Risk Mental States (CAARMS) and 31 healthy controls (HC) were studied while performing a novelty salience fMRI task that engaged an a priori hippocampal-striatal-midbrain circuit of interest. The CHR sample was then followed clinically for a mean of 59.7 months (~5 y), when clinical outcomes were assessed in terms of transition (CHR-T) or non-transition (CHR-NT) to psychosis (CAARMS criteria): during this period, 13 individuals (17%) developed a psychotic disorder (CHR-T) and 63 did not. Functional activation and effective connectivity within a hippocampal-striatal-midbrain circuit were compared between groups. In CHR individuals compared to HC, hippocampal response to novel stimuli was significantly attenuated (P = .041 family-wise error corrected). Dynamic Causal Modelling revealed that stimulus novelty modulated effective connectivity from the hippocampus to the striatum, and from the midbrain to the hippocampus, significantly more in CHR participants than in HC. Conversely, stimulus novelty modulated connectivity from the midbrain to the striatum significantly less in CHR participants than in HC, and less in CHR participants who subsequently developed psychosis than in CHR individuals who did not become psychotic. Our findings are consistent with preclinical evidence implicating hippocampal-striatal-midbrain circuit dysfunction in altered salience processing and the onset of psychosis
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