Mathematics, Statistics & Physics: Recent submissions

Now showing items 361-380 of 783

    • Effects of SARS-CoV-2 Alpha, Beta, and Delta variants, age, vaccination, and prior infection on infectiousness of SARS-CoV-2 infections 

      Qassim, Suelen H.; Hasan, Mohammad R.; Tang, Patrick; Chemaitelly, Hiam; Ayoub, Houssein H.; ... more authors ( Frontiers Media , 2022 , Article)
      In 2021, Qatar experienced considerable incidence of SARS-CoV-2 infection that was dominated sequentially by the Alpha, Beta, and Delta variants. Using the cycle threshold (Ct) value of an RT-qPCR-positive test to proxy ...

    • A Note on a Class of Generalized Parabolic Marcinkiewicz Integrals along Surfaces of Revolution 

      Ali, Mohammed; Al-Qassem, Hussain ( MDPI , 2022 , Article)
      In this article, certain sharp Lp estimates for a specific class of generalized Marcinkiewicz operators with mixed homogeneity associated to surfaces of revolution are established. By virtue of Yano’s extrapolation ...

    • Least-squares spectral methods for ODE eigenvalue problems 

      Hashemi, Behnam; Nakatsukasa, Yuji ( Society for Industrial and Applied Mathematics , 2022 , Article)
      We develop spectral methods for ODEs and operator eigenvalue problems that are based on a least-squares formulation of the problem. The key tool is a method for rectangular generalized eigenvalue problems, which we extend ...

    • Numerical investigation of a novel solar cell based on a modified perovskite with PPP polymer 

      S., Yasin; Moustafa, M. ( Elsevier , 2022 , Article)
      In this paper, a new, highly efficient and eco-friendly solar cell device based on a modified perovskite material from CsMAFA, with a polymer as an absorber layer, is modelled and simulated by utilizing the SCAPS-1D. An ...

    • Mathematical modeling of the SARSCoV-2 epidemic in Qatar and its impact on the national response to COVID-19 

      Ayoub, Houssein H.; Chemaitelly, Hiam; Seedat, Shaheen; Makhoul, Monia; Kanaani, Zaina Al; ... more authors ( University of Edinburgh , 2021 , Article)
      Background Mathematical modeling constitutes an important tool for planning robust responses to epidemics. This study was conducted to guide the Qatari national response to the severe acute respiratory syndrome coronavirus ...

    • SARS-CoV-2 infection hospitalization, severity, criticality, and fatality rates in Qatar 

      Seedat, Shaheen; Chemaitelly, Hiam; Ayoub, Houssein H.; Makhoul, Monia; Mumtaz, Ghina R.; ... more authors ( Nature Research , 2021 , Article)
      The SARS-CoV-2 pandemic resulted in considerable morbidity and mortality as well as severe economic and societal disruptions. Despite scientific progress, true infection severity, factoring both diagnosed and undiagnosed ...

    • Assessment of the Risk of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Reinfection in an Intense Reexposure Setting 

      Abu-Raddad, Laith J.; Chemaitelly, Hiam; Malek, Joel A.; Ahmed, Ayeda A.; Mohamoud, Yasmin A.; ... more authors ( NLM (Medline) , 2021 , Article)
      BACKGROUND: Risk of reinfection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unknown. We assessed the risk and incidence rate of documented SARS-CoV-2 reinfection in a cohort of laboratory-confirmed ...

    • Portfolio Selection Problem Using CVaR Risk Measures Equipped with DEA, PSO, and ICA Algorithms 

      Hamdi, Abdelouahed; Karimi, Arezou; Mehrdoust, Farshid; Belhaouari, Samir Brahim ( MDPI , 2022 , Article)
      Investors always pay attention to the two factors of return and risk in portfolio optimization. There are different metrics for the calculation of the risk factor, among which the most important one is the Conditional ...

    • Functional linear models for interval-valued data 

      Beyaztas, Ufuk; Shang, Han Lin; Abdel-Salam, Abdel Salam G. ( Taylor and Francis Group , 2022 , Article)
      Aggregation of large databases in a specific format is a frequently used process to make the data easily manageable. Interval-valued data is one of the data types that is generated by such an aggregation process. Using ...

    • Monitoring SEIRD model parameters using MEWMA for the COVID-19 pandemic with application to the state of Qatar 

      Boone, Edward L.; Abdel-Salam, Abdel Salam G.; Sahoo, Indranil; Ghanam, Ryad; Chen, Xi; ... more authors ( Taylor and Francis Group , 2021 , Article)
      During the current COVID-19 pandemic, decision-makers are tasked with implementing and evaluating strategies for both treatment and disease prevention. In order to make effective decisions, they need to simultaneously ...

    • A Note on Parabolic Maximal Operators along Surfaces of Revolution via Extrapolation 

      Ali, Mohammed; Al-Qassem, Hussain ( MDPI , 2022 , Article)
      Under weak conditions on the kernels, we obtain sharp Lp bounds for rough parabolic maximal integral operators over surfaces of revolution. By virtue of these bounds along with Yano’s extrapolation argument, we confirm the ...

    • Factors affecting university image among graduate alumni: A case study of Qatar university 

      Khalifa A., Haza; Abdel-Salam, Abdel-Salam G.; Mollazehi, Mohammad D.; Mohamed, Radwa Ismail; Hasan, Mahmood A.; ... more authors ( Elsevier , 2022 , Article)
      Various factors influence the students' perception of universities and university image. This study explores five factors affecting university image among Graduate Alumni. Surveys, administered to 597 graduate alumni were ...

    • A diagnostic tool for family and marriage counseling with Muslim couples 

      Soliman, Abdrabo; Abdel-Salam, Abdel Salam G.; Ahmed, Mervat ( Springer Nature , 2022 , Article)
      This study aimed to describe the development and psychometric properties of a questionnaire for Muslim couples and families based on how couples view and experience marital and family issues. A questionnaire was developed ...

    • EXPLORATION of the NOVEL CORONA VIRUS TRANSITION GRAPHS with PETRINET MODELING 

      Alam, Fatima; Abdel-Salam, Abdel Salam G.; Sohail, Ayesha; Yousaf, M.; Tunç, Sümeyye ( World Scientific Publishing , 2021 , Article)
      Corona virus (CoV) is a group of viruses with non-bifurcated, single-stranded, and positive-sense RNA genomes. Apart from infecting several economically significant vertebrates (such as pigs and chickens), it is reported ...

    • Forecasting the impact of environmental stresses on the frequent waves of COVID19 

      Yu, Zhenhua; Abdel-Salam, Abdel Salam G.; Sohail, Ayesha; Alam, Fatima ( Springer , 2021 , Article)
      A novel approach to link the environmental stresses with the COVID-19 cases is adopted during this research. The time-dependent data are extracted from the online repositories that are freely available for knowledge and ...

    • Practitioners guide on parametric, nonparametric, and semiparametric profile monitoring 

      Jones, Chelsea L.; Abdel-Salam, Abdel Salam G.; Mays, D'Arcy ( Wiley , 2021 , Article Review)
      Profile monitoring is one of the methods used in statistical process control ((Formula presented.)) to understand the functional relationship between response and explanatory variables by tracking this relationship and ...

    • Robust profile monitoring for phase II analysis via residuals 

      Nassar, Sara H.; Abdel-Salam, Abdel Salam G. ( Wiley , 2022 , Article)
      Many studies were conducted for fitting models using parametric and non-parametric techniques; in fact, their fits may be biased and have inflated the estimated variances when the model is misspecified, respectively. Thus, ...

    • Evaluating the Online Learning Experience at Higher Education Institutions 

      Abdel-Salam, Abdel Salam G.; Hazaa, Khalifa; Abu-Shanab, Emad Ahmed ( IGI Global , 2022 , Article)
      In light of recent COVID-19 pandemic, universities had to cope by resorting to online learning without previous preparation. This paper tries to investigate student satisfaction with online learning. The literature review ...

    • A novel procedure for constructing invariant subspaces of a set of matrices 

      Al-Dweik, Ahmad Y.; Ghanam, Ryad; Thompson, Gerard; Azad, Hassan ( Springer , 2022 , Article)
      A problem that is frequently encountered in a variety of mathematical contexts is to find the common invariant subspaces of a single or of a set of matrices. A new method is proposed that gives a definitive answer to this ...

    • Protection of Omicron sub-lineage infection against reinfection with another Omicron sub-lineage 

      Chemaitelly, Hiam; Ayoub, Houssein H.; Coyle, Peter; Tang, Patrick; Yassine, Hadi M.; ... more authors ( Nature Research , 2022 , Article)
      There is significant genetic distance between SARS-CoV-2 Omicron (B.1.1.529) variant BA.1 and BA.2 sub-lineages. This study investigates immune protection of infection with one sub-lineage against reinfection with the other ...