When a low spatial frequency noise mask is superimposed onto a luminance staircase, the perceived brightness pattern is dramatically altered although the edges remain visible. We measured contrast thresholds for the edges and for the illusory scalloping (Chevreul-illusion), as a function of noise center spatial frequency. The masking tuning functions overlapped, but peaked at different spatial frequencies and contrast levels. The results suggest that perceived brightness is triggered only by the low spatial frequency components of the edges--the high spatial frequency components are not able to produce a brightness pattern.
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http://dx.doi.org/10.1016/j.visres.2004.03.005 | DOI Listing |
Comput Med Imaging Graph
January 2025
CAS Key Laboratory of Molecular Imaging, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing 100049, China; National Key Laboratory of Kidney Diseases, Beijing 100853, China. Electronic address:
In clinical optical molecular imaging, the need for real-time high frame rates and low excitation doses to ensure patient safety inherently increases susceptibility to detection noise. Faced with the challenge of image degradation caused by severe noise, image denoising is essential for mitigating the trade-off between acquisition cost and image quality. However, prevailing deep learning methods exhibit uncontrollable and suboptimal performance with limited interpretability, primarily due to neglecting underlying physical model and frequency information.
View Article and Find Full Text PDFPLOS Glob Public Health
January 2025
Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America.
Eleven countries have been certified as malaria free since 2016, but none of these are in subSaharan Africa where elimination challenges are unique. The 1-3-7 focus investigation approach is an implementation strategy that requires case reporting, case investigation/classification, and focal classification/response to be completed one, three, and seven days, respectively, after index case diagnosis. Real-time short-messaging-service reports are sent at each step to add accountability and data transparency.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Economics, Centre for Entrepreneurship and Spatial Economics (CEnSE), Jönköping International Business School, Jönköping, Sweden.
Background: The Swedish COVID-19 strategy aimed to protect vulnerable groups through targeted measures, categorizing individuals aged 70 and above as high-risk. This study examines the impact of such group-based risk assessments on subjective health and virus-related concerns among older adults.
Methods: We analyzed survey data from the SOM Institute for 68- to 71-year-olds in 2019 (N = 684) and 2020 (N = 726).
Geroscience
January 2025
Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, Moscow, 125047, Russia.
Age-related dependencies of electric and spectral powers in conventional frequency bands were studied by the newly proposed method of detailed spectral analysis. The magnetic encephalograms (MEG) and magnetic resonance images (MRI) of the head were obtained from the open archive Cam-CAN. The spatial distributions of elementary spectral components (MEG-based functional tomograms) were reconstructed from MEG for 501 subjects (248 males and 253 females, ages 18-88 years, mean age 54.
View Article and Find Full Text PDFJ Math Biol
January 2025
School of Mathematics and Statistics, Northeast Normal University, 5268 Renmin Street, Changchun, 130024, Jilin, People's Republic of China.
Wild birds are one of the main natural reservoirs for avian influenza viruses, and their migratory behavior significantly influences the transmission of avian influenza. To better describe the migratory behavior of wild birds, a system of reaction-advection-diffusion equations is developed to characterize the interactions among wild birds, poultry, and humans. By the next-generation operator, the basic reproduction number of the model is formulated.
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