Tamer Oraby

Tamer Oraby
University of Texas Rio Grande Valley · Mathematical and statistical sciences

Doctor of Philosophy
Associate professor @ University of Texas Rio Grande Valley See also: https://www.researchgate.net/profile/Tamer-Oraby

About

58
Publications
6,492
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
556
Citations

Publications

Publications (58)
Article
Full-text available
Background Kuwait had its first COVID-19 in late February, and until October 6, 2020 it recorded 108,268 cases and 632 deaths. Despite implementing one of the strictest control measures-including a three-week complete lockdown, there was no sign of a declining epidemic curve. The objective of the current analyses is to determine, hypothetically, th...
Article
Full-text available
Chronic wasting disease (CWD) is a spongiform encephalopathy disease caused by the transmission of infectious prion agents. CWD is a fatal disease that affects wild and farmed cervids in North America with few cases reported overseas. Social interaction of cervids, feeding practices by wildlife keepers and climate effects on the environmental carry...
Preprint
Full-text available
In this paper, we study observational social learning and vaccine-preventable childhood disease spread over a bi-layer household network. The two overlapping networks are either Erd\H{o}s-R\'{e}nyi (random) network or Barab\'{a}si-Albert network. We introduce a new Bayesian rule of observational social learning over the social network of which othe...
Article
Full-text available
Background Anticipating an initial shortage of vaccines for COVID-19, the Centers for Disease Control (CDC) in the United States developed priority vaccine allocations for specific demographic groups in the population. This study evaluates the performance of the CDC vaccine allocation strategy with respect to multiple potentially competing vaccinat...
Article
Government agencies and fact-checking websites have been combating the spread of falsehoods on social media by issuing correction messages. There has been, however, no research on the effectiveness of correction messages on falsehoods and their dynamic interaction. We develop a theoretical model of the competition between falsehoods and correction...
Article
Full-text available
Externality exists in healthcare when an individual benefits from others being healthy as it reduces the probability of getting sick from illness. Healthy workers are considered to be the more productive labourers leading to a country’s positive economic growth over time. Several research studies have modelled disease transmission and its economic...
Poster
Full-text available
Anticipating an initial shortage of vaccines for COVID-19, the Centers for Disease Control (CDC) in the United States developed priority vaccine allocations for specific demographic groups in the population. In this poster, I present our recent study that evaluates the performance of the CDC vaccine allocation strategy with respect to multiple pote...
Preprint
Full-text available
Background: Anticipating an initial shortage of vaccines for COVID-19, the Centers for Disease Control (CDC) in the United States developed priority vaccine allocations for specific demographic groups in the population. This study evaluates the performance of the CDC vaccine allocation strategy with respect to multiple potentially competing vaccina...
Article
Full-text available
At the beginning of August 2020, the Rio Grande Valley (RGV) of Texas experienced a rapid increase of coronavirus disease 2019 (abbreviated as COVID-19) cases and deaths. This study aims to determine the optimal levels of effective social distancing and testing to slow the virus spread at the outset of the pandemic. We use an age-stratified eight c...
Article
Full-text available
Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a World Health Organization designated pandemic that can result in severe symptoms and death that disproportionately affects older patients or those with comorbidities. Kuwait reported its first imported cases of COVID-19 on February 24, 2020. Analysis of data from the first three mont...
Chapter
Full-text available
The recent COVID-19 pandemic has caused significant societal impacts. Besides loss of life there were large additional costs incurred by every country including the treatment of patients and costs to implement response plans. The pandemic resulted in major economic disruptions and stalled growth worldwide due to travel bans, lockdowns, social dista...
Article
Full-text available
The application, timing, and duration of lockdown strategies during a pandemic remain poorly quantified with regards to expected public health outcomes. Previous projection models have reached conflicting conclusions about the effect of complete lockdowns on COVID-19 outcomes. We developed a stochastic continuous-time Markov chain (CTMC) model with...
Preprint
Full-text available
Background: Kuwait had its first COVID-19 in late February, and until October 6, 2020 it recorded 108,268 cases and 632 deaths. Despite implementing one of the strictest control measures-including a three-week complete lockdown, there was no sign of a declining epidemic curve. The objective of the current analyses is to determine, hypothetically, t...
Preprint
Full-text available
Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a World Health Organization designated pandemic that can result in severe symptoms and death that disproportionately affects older patients or those with comorbidities. Kuwait reported its first imported cases of COVID-19 on February 24, 2020. Analysis of data from the first three mont...
Article
Full-text available
Background: Anticipating an initial shortage of vaccines for COVID-19, the Centers for Disease Control (CDC) in the United States developed priority vaccine allocations for specific demographic groups in the population. This study evaluates the performance of the CDC vaccine allocation strategy with respect to multiple potentially competing vaccina...
Preprint
Full-text available
The application, timing, and duration of lockdown strategies during a pandemic remain poorly quantified with regards to expected public health outcomes. Previous projection models have reached conflicting conclusions about the effect of complete lockdowns on COVID-19 outcomes. We developed a stochastic continuous-time Markov chain (CTMC) model with...
Article
In this work we study a stochastic susceptible‐infected (SI) model with space‐uniform white noise. We present conditions to find exact solutions and numerical simulations are compared to these exact solutions in some cases. We demonstrate that the model is exponentially asymptotically stable almost surely. We show the global stability and local sta...
Article
Full-text available
Middle East respiratory syndrome coronavirus (MERS-CoV) is an emerging zoonotic coronavirus that has a tendency to cause significant healthcare outbreaks among patients with serious comorbidities. We analyzed hospital data from the MERS-CoV outbreak in King Abdulaziz Medical Center, Riyadh, Saudi Arabia, June–August 2015 using the susceptible-expos...
Article
Permeable pavements are often developed as alternatives to traditional pavement (TP) systems for the mitigation of urban storm-water runoff impairment. The objective of this study was to evaluate the stormwater runoff and pollutant load-reduction performance of an enhanced permeable interlocking concrete pavement system with enlarged joints filled...
Article
Full-text available
In this paper, we compare the performance between systems of ordinary and (Caputo) fractional differential equations depicting the susceptible-exposed-infectious-recovered (SEIR) models of diseases. In order to understand the origins of both approaches as mean-field approximations of integer and fractional stochastic processes, we introduce the fra...
Article
Full-text available
In this work, we prove the persistence in time of superoscillations for the Schrödinger equation with time‐dependent coefficients. In order to prove the persistence of superoscillations, we have conditioned the coefficients to satisfy a Riccati system, and we have expressed the solution as a convolution operator in terms of solutions of this Riccat...
Preprint
Full-text available
In this paper, we compare the performance between systems of ordinary and (Caputo) fractional differential equations depicting the susceptible-exposed-infectious-recovered (SEIR) models of diseases. In order to understand the origins of both approaches as mean-field approximations of integer and fractional stochastic processes, we introduce the fra...
Poster
We compare the performance of systems of ordinary and (Caputo) fractional differential equations depicting the susceptible-exposed-infected-recovered (SEIR) models of diseases. We examine the validity of the two approaches against empirical courses of epidemics, we fit both of them to case counts of three measles epidemics that occurred during the...
Preprint
In this work we study the persistence on time of superoscillations for Schr\"{o}dinger equations with variable coefficients. We generalize results obtained for particular Hamiltonians to more general quadratic Hamiltonians. Including Caldirola-Kanai and degenerate parametric harmonic oscillator Hamiltonians.
Chapter
The relationship between socioeconomic development and environmental degradation measures such as SO2, CO, and NOx emissions and deforestation has sometimes been claimed to follow an environmental Kuznets curve. However, in an era of globalization where the populations that experience economic benefits may be geographically distant from the populat...
Article
Full-text available
Many epidemiological studies assessing the relationship between exposure and disease are carried out without data on individual exposures. When this barrier is encountered in occupational studies, the subject exposures are often evaluated with a job-exposure matrix (JEM), which consists of mean exposure for occupational categories measured on a com...
Article
Nosocomial epidemics are infectious diseases which spread among different types of susceptible individuals in a health-care facility. To model this type of epidemics, we use a multi-type branching process with a multivariate negative binomial offspring distribution. In particular, we estimate the basic reproduction number R0 and study its relations...
Article
Full-text available
This article summarises efforts at disease surveillance and risk management of chronic wasting disease (CWD). CWD is a fatal neurodegenerative disease of cervids and is considered to be one of the most contagious of the transmissible spongiform encephalopathies (TSEs). Evidence has demonstrated a strong species barrier to CWD for both human and far...
Article
A high degree of uncertainty exists for chronic wasting disease (CWD) transmission factors in farmed and wild cervids. Evaluating the factors is important as it helps to inform future risk management strategies. Expert opinion is often used to assist decision making in a number of health, science, and technology domains where data may be sparse or...
Article
ABSTARCT Chronic wasting disease (CWD) is a neurodegenerative, protein misfolding disease affecting cervids in North America in epidemic proportions. While the existence of CWD has been known for more than 40 years, risk management efforts to date have not been able to curtail the spread of this condition. An expert elicitation exercise was carried...
Article
The application of a recently developed mathematical model for predicting the spread of chronic wasting disease (CWD) in wild deer was assessed under different scenarios where harvesting is employed in disease management. A process-based mathematical model for CWD transmission in wild deer populations was recently developed and parameterized by Al-...
Article
Seventeen typical cases of bovine spongiform encephalopathy (BSE) were detected in Canada the period of 2003-2011. The clinical incidence of BSE was censored by early slaughter, death, or exportation of infected cattle due to the long incubation period of BSE disease. The aim of this study was to estimate the infection incidence of BSE in birth coh...
Article
Bovine spongiform encephalopathy (BSE) appeared in the United Kingdom in the mid 1980s, and has been attributed to the use of meat and bone meal (MBM) in cattle feed contaminated with a scrapie-like agent. Import of infectious materials from a country where BSE has occurred is believed to be the major factor underlying the spread of the BSE epidemi...
Article
Full-text available
Interactions between disease dynamics and vaccinating behavior have been explored in many coupled behavior-disease models. Cognitive effects such as risk perception, framing, and subjective probabilities of adverse events can be important determinants of the vaccinating behaviour, and represent departures from the pure "rational" decision model tha...
Article
Full-text available
When the bovine spongiform encephalopathy (BSE) epidemic first emerged in the United Kingdom in the mid 1980s, the etiology of animal prion diseases was largely unknown. Risk management efforts to control the disease were also subject to uncertainties regarding the extent of BSE infections and future course of the epidemic. As understanding of BSE...
Article
Disease transmission depends on the interplay between the infectious agent and the behavior of the host. Some diseases, such as Chronic Wasting Disease, can be transmitted directly between hosts as well as indirectly via the environment. The social behavior of hosts affects both of these pathways, and a successful intervention requires knowledge of...
Article
Full-text available
Mathematical models that couple disease dynamics and vaccinating behaviour often assume that the incentive to vaccinate disappears if disease prevalence is zero. Hence, they predict that vaccine refusal should be the rule, and elimination should be difficult or impossible. In reality, countries with non-mandatory vaccination policies have usually b...
Article
We give a simple formula to calculate the speed of weighted random walks on nonnegative integers and on spherically symmetric trees.
Article
Full-text available
Much uncertainty surrounds transmission of transmissible spongiform encephalopathies (TSEs) through blood and blood derived products. A first expert elicitation with 14 experts was conducted in March 2008, and a second re-elicitation involving 11 experts was held a year later in March 2009. Both expert groups were calibrated using a series of seed...
Article
Full-text available
There is a high level of uncertainty surrounding the potential for iatrogenic prion transmission through transplantation, medical instrument reuse, blood transfusion, and blood product use due to a lack of evidence-based research on this important risk issue. A group of specialists was enlisted to evaluate some of the knowledge gaps in this area us...
Article
In a frequency-selective slow-fading channel in a multiple-input multiple-output (MIMO) system, the channel matrix is of the form of a block matrix. A method is proposed to calculate the limit of the eigenvalue distribution of block matrices if the size of the blocks tends to infinity. Asymptotic eigenvalue distribution of is also calculated, where...
Article
In this paper we pursue our study, in Konsowa and Oraby 2003a. [Dimensions of random trees. Statist. Probab. Lett. 62(1), 49-60] and Konsowa and Oraby 2003b. [Fractal dimensions and random walks on random trees. J. Statist. Plann. Inference 116(2), 333-342], on dimensions of some random trees. These dimensions are, for polynomially growing graphs,...
Article
Full-text available
To analyze the limiting spectral distribution of some random block-matrices, Girko (Random Oper. Stoch. Equ. 8(2), 189–194, 2000) uses a system of canonical equations from (An Introduction to Statistical Analysis of Random Arrays. VSP, Utrecht, 1998). In this paper, we use the method of moments to give an integral form for the almost sure limiting...
Article
Full-text available
In a frequency selective slow-fading channel in a MIMO system, the channel matrix is of the form of a block matrix. We propose a method to calculate the limit of the eigenvalue distribution of block matrices if the size of the blocks tends to infinity. We will also calculate the asymptotic eigenvalue distribution of $HH^*$, where the entries of $H$...
Article
Full-text available
We are going to study the limiting spectral measure of fixed dimensional Hermitian block-matrices with large dimensional Wigner blocks. We are going also to identify the limiting spectral measure when the Hermitian block-structure is Circulant. Using the limiting spectral measure of a Hermitian Circulant block-matrix we will show that the spectral...
Article
Full-text available
In a frequency selective slow-fading channel in a MIMO system, the channel matrix is of the form of a block matrix. This paper proposes a method to calculate the limit of the eigenvalue distribution of block matrices if the size of the blocks tends to infinity. While it considers random matrices, it takes an operator-valued free probability approac...
Article
We determine the fractal dimension df of infinite spherically symmetric random trees (all vertices at distance n from the root have the same degree dn where {dn} are independent random variables). If dn takes the value 3 or 2 with probabilities qn and 1−qn, then a.s. We show how df is closely related to the type of the simple random walks (SRW) on...
Article
In this paper we show, for Galton-Watson tree T of resistance R, that R-Rn decays exponentially in n where Rn denotes the resistance of the portion of T between the root and level n. We also determine a formula for the resistance dimension of spherically symmetric random trees and prove that it is equal to the fractal dimension. We emphasize the re...

Network

Cited By

Projects