23,658 research outputs found
Modulational Instability in Bose-Einstein Condensates under Feshbach Resonance Management
We investigate the modulational instability of nonlinear Schr{\"o}dinger
equations with periodic variation of their coefficients. In particular, we
focus on the case of the recently proposed, experimentally realizable protocol
of Feshbach Resonance Management for Bose-Einstein condensates. We derive the
corresponding linear stability equation analytically and we show that it can be
reduced to a Kronig-Penney model, which allows the determination of the windows
of instability. The results are tested numerically in the absence, as well as
in the presence of the magnetic trapping potential
Deep Learning networks with p-norm loss layers for spatial resolution enhancement of 3D medical images
Thurnhofer-Hemsi K., López-Rubio E., Roé-Vellvé N., Molina-Cabello M.A. (2019) Deep Learning Networks with p-norm Loss Layers for Spatial Resolution Enhancement of 3D Medical Images. In: Ferrández Vicente J., Álvarez-Sánchez J., de la Paz López F., Toledo Moreo J., Adeli H. (eds) From Bioinspired Systems and Biomedical Applications to Machine Learning. IWINAC 2019. Lecture Notes in Computer Science, vol 11487. Springer, ChamNowadays, obtaining high-quality magnetic resonance (MR) images is a complex problem due to several acquisition factors, but is crucial in order to perform good diagnostics. The enhancement of the resolution is a typical procedure applied after the image generation. State-of-the-art works gather a large variety of methods for super-resolution (SR), among which deep learning has become very popular during the last years. Most of the SR deep-learning methods are based on the min-
imization of the residuals by the use of Euclidean loss layers. In this paper, we propose an SR model based on the use of a p-norm loss layer to improve the learning process and obtain a better high-resolution (HR) image. This method was implemented using a three-dimensional convolutional neural network (CNN), and tested for several norms in order to determine the most robust t. The proposed methodology was trained and tested with sets of MR structural T1-weighted images and showed
better outcomes quantitatively, in terms of Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity Index (SSIM), and the restored and the calculated residual images showed better CNN outputs.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
The effects of sounds and food odour on crowd behaviours in urban public open spaces
Few studies have investigated the integrated effects of sound and odour on people with the purpose of improving the use of urban spaces. Therefore, this study aimed to provide further insight into such effects from the perspective of crowd behaviour. A covert behavioural observation experiment was conducted in a typical urban commercial pedestrian street, using the smell of a bakery as the odour source, while reproducing typical urban sound sources of music and fan sound (along with a condition where no sound was played) with and without odour. The present results show that for crowd path, in the no-odour condition, playing music significantly attracted the crowd, while fan sound tended to make the crowd path farther away from the sensory sources. With the bakery odour, individuals approached the sensory sources closer when playing the sound, whether it was music or fan sound. With regard to crowd speed, music significantly reduced it and the greater the proximity to the sound source, the slower the crowd speed. Fan sound increased the crowd speed, which was significantly higher in the presence rather than absence of bakery odour, and the average speed decreased gradually as proximity to the sensory sources increased. Finally, with regard to the duration time of the crowd, it increased with music and decreased with fan sound. The bakery odour also significantly increased the duration time. However, the interaction effect between sound and odour on crowd speed and duration time was not significant
Influence of distance from traffic sounds on physiological indicators and subjective evaluation
This study examined the influence of different distances of traffic noise and sea sounds on physiological indicators and subjective evaluation. Scene re-creations employed three types of distance: actual close sounds (close to the sound source recorded on site), actual distant sounds (distance attenuation recorded on site) and artificial distant sounds (reduction of the same decibel level across frequencies). Participants displayed higher heart rate, amplitude of the R-wave (ΔR), heart rate variability, respiration rate, and skin conductance level (SCL) when close to the sound source. Actual distance attenuation affected most subjective evaluation factors (except for Familiarity and Excitement). The ΔR, electroencephalography alpha reactivity, and electroencephalography beta reactivity with actual distant sounds were lower and SCL was higher, relative to those with artificial distant sounds. These findings provide a reference for governments and urban planners when working to improve quality of life in urban areas
The multisensory environmental evaluations of sound and odour in urban public open spaces
Few studies have focused on the multisensory perception of audio–olfactory interaction with the purpose of improving the use of urban spaces. This study conducted multisensory environmental evaluations in three urban open spaces in China with the aim of verifying the existence of audio–olfactory interaction in the urban environments and providing different perspectives for the improvement of urban environmental quality. A sensewalk approach was adopted in the study, and the main research contents were: the odour’s effects on sound source and sound environment evaluations, and the sound’s effects on odour source and odour environment evaluations. The results indicated that food odour improved acoustic comfort and sound congruency and reduced subjective loudness. Pollution odour worsened the assessment of traffic and lowered subjective loudness. Sound decreased the subjective intensity of odour and exacerbated its evaluation. Additionally, food odour enhanced the sound environment assessment of pedestrian streets, while pollution odour worsened it. Sound had a weak impact on odour environment evaluations. The masking effect between sound and odour showed that the presence of the latter decreased subjective loudness while increased sound diminished the subjective intensity of odour. Furthermore, odour’s influence on sound evaluations was greater than the influence of sound on odour evaluations. These findings have implications for the planning and design of a livable and comfortable urban environment through the perspective of sensory interaction
Physiological indicators and subjective restorativeness with audio-visual interactions in urban soundscapes
The present study aimed to identify the trends of changes in physiological indicators and subjective restorativeness in response to audio-visual interactions in the environment. Four scenarios types were presented using four different modalities (video-sound, image-sound, sound-only, and video-only; each modality was evaluated by independent groups of subjects). The physiological responses and subjective restoration of subjects were measured to assess the interactions between the audio-visual modalities. These data were also analysed to determine the physiological and subjective differences between dynamic and static visual presentations. We found that with visual modalities, the heart rate (HR), heart rate variability (HRV) calculated using the standard deviation of the NN intervals (SDNN[sbnd]HRV), high-frequency band in the HRV power spectrum (HF[sbnd]HRV), alpha reactivity on electroencephalography, and skin temperature (ST) decreased; however, the beta reactivity on EEG and skin conductance level (SCL) increased. With auditory modalities, the SDNN[sbnd]HRV, HF-HRV, ST, and respiration depth decreased; however, the respiration rate and SCL increased. Use of static images and sound to reproduce the natural environment evoked more physiological comfort and subjective restorativeness. These findings could provide physiological insights for the theory of the restorative environment
Tolerance to oxidative stress is associated with both oxidative stress response and inherent growth in a fungal wheat pathogen
Reactive oxygen species are toxic byproducts of aerobic respiration that are also important in mediating a diversity of cellular functions. Reactive oxygen species form an important component of plant defenses to inhibit microbial pathogens during pathogen–plant interactions. Tolerance to oxidative stress is likely to make a significant contribution to the viability and pathogenicity of plant pathogens, but the complex network of oxidative stress responses hinders identification of the genes contributing to this trait. Here, we employed a forward genetic approach to investigate the genetic architecture of oxidative stress tolerance in the fungal wheat pathogen Zymoseptoria tritici. We used quantitative trait locus (QTL) mapping of growth and melanization under axenic conditions in two cross-populations to identify genomic regions associated with tolerance to oxidative stress. We found that QTLs associated with growth under oxidative stress as well as inherent growth can affect oxidative stress tolerance, and we identified two uncharacterized genes in a major QTL associated with this trait. Our data suggest that melanization does not affect tolerance to oxidative stress, which differs from what was found for animal pathogens. This study provides a whole-genome perspective on the genetic basis of oxidative stress tolerance in a plant pathogen
Four simplified gradient elasticity models for the simulation of dispersive wave propagation
Gradient elasticity theories can be used to simulate dispersive wave propagation as it occurs in heterogeneous materials. Compared to the second-order partial differential equations of classical elasticity, in its most general format gradient elasticity also contains fourth-order spatial, temporal as well as mixed spatial temporal derivatives. The inclusion of the various higher-order terms has been motivated through arguments of causality and asymptotic accuracy, but for numerical implementations it is also important that standard discretization tools
can be used for the interpolation in space and the integration in time. In this paper, we will formulate four different simplifications of the general gradient elasticity theory. We will study the dispersive properties of the models, their causality according to Einstein and their behavior in simple initial/boundary value problems
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