We compute analytically, for large N, the probability distribution of the number of positive eigenvalues (the index N+) of a random N x N matrix belonging to Gaussian orthogonal (beta=1), unitary (beta=2) or symplectic (beta=4) ensembles. The distribution of the fraction of positive eigenvalues c=N+/N scales, for large N, as P(c,N) approximately = exp[-betaN(2)Phi(c)] where the rate function Phi(c), symmetric around c=1/2 and universal (independent of beta), is calculated exactly. The distribution has non-Gaussian tails, but even near its peak at c=1/2 it is not strictly Gaussian due to an unusual logarithmic singularity in the rate function.
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http://dx.doi.org/10.1103/PhysRevLett.103.220603 | DOI Listing |
BMC Ophthalmol
January 2025
Department of Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Background: The psychometric properties of the Convergence Insufficiency Symptom Survey (CISS) have been previously determined across the younger adult population. This study investigated the psychometric properties of the CISS in presbyopic adults via classical and Rasch analysis.
Methods: A total of 100 presbyopic individuals (40-60 years) were selected with far and near acuity of 20/20 with their habitual spectacles; 50 had convergence insufficiency and 50 had normal binocular vision.
J Clin Med
December 2024
Department of Pharmaceutical Sciences, College of Pharmacy, Princess Nourah Bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia.
The objective was to develop and validate a multidimensional scale that measures adherence levels to antiseizure medications and detects patients' reasons for non-adherence. A new scale was developed, namely the "Adherence Scale for Anti-Seizure Medication(s)-10 items [ASASM-10]". It consists of ten statements that cover different causes of non-adherence to antiseizure medications.
View Article and Find Full Text PDFBull Math Biol
January 2025
Department of Mathematics, University of Trento, Via Sommarive 14, Povo, 38123, Trento, Italy.
One of the strategies used in some countries to contain the COVID-19 epidemic has been the test-and-isolate policy, generally coupled with contact tracing. Such strategies have been examined in several simulation models, but a theoretical analysis of their effectiveness in simple epidemic model is, to our knowledge, missing. In this paper, we present four epidemic models of either SIR or SEIR type, in which it is assumed that at fixed times the whole population (or a part of the population) is tested and, if positive, isolated.
View Article and Find Full Text PDFEnviron Monit Assess
December 2024
Department of Environmental Studies, North-Eastern Hill University, Shillong, Meghalaya, India.
In this study, we assessed the changes in the physical and chemical characteristics of the soil samples collected from the artisanal and small-scale limestone mining site in Sohra (Cherrapunjee), Meghalaya, by comparing them with the non-mining site. Eleven distinct soil parameters, namely pH, electrical conductivity (EC), texture (ST), moisture content (MC), bulk density (BD), total porosity (TP), water holding capacity (WHC), organic carbon (OC), total nitrogen (TN), available phosphorus (AP), and exchangeable potassium (EK), were evaluated seasonally (winter, pre-monsoon, and post-monsoon) for 2 years. The results showed that limestone mining has significantly affected the soil quality.
View Article and Find Full Text PDFMath Biosci Eng
October 2024
Computer and Information Science and Engineering Department, University of Florida, Gainesville, FL 32611, USA.
We present an individual-level probabilistic model to evaluate the effectiveness of two traditional control measures for infectious diseases: the isolation of symptomatic individuals and contact tracing (plus subsequent quarantine). The model allows us to calculate the reproduction number and the generation-time distribution under the two control measures. The model is related to the work of Fraser et al.
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