قرائن الترجیح العامة بين الروايات المختلفة المعلة مع الأمثلة التطبيقية من كتاب العلل الواردة في الأحاديث النبوية

In the field of Defective Narrations or Ahādith Mu'allah, collection and study of chains and tracks have great importance. It is this process in which the difference in the texts and chains of narrations comes to the surface and their defects become evident. This difference in text and chains has different types, like: Waṣl wa Irsāl: the presence or the absence of a narrator in the chain of a narration. Raf' wa Waqf: attribution of a narration to the Prophet (PBUH) or to his companion. Addition or Deletion in the text or in the chain of a narration Sometimes, a narration has more than one types of differences. To determine the preference among the differences of the said types, scholars of Hadith (muḥaddithīn) have to use Presumptions of Preference or Qarā'in al-Tarjīḥ. Some of these presumptions are common among the hadith scholars known as Common Presumptions or Qarā'in Aghlabiyah. The present research discusses these presumptions with examples in light of the book al-'Ilal al-Wāridah fi al- Ahādith al-Nabawiyah authored by Imām al-Dārqutnī.

Mathematical Modeling and Optimal Control of a Vector Borne Disease

This dissertation is concerned with mathematical modeling and optimal control of a vector borne disease. We derive and rigorously analyze mathematical models to better understand the transmission and spread of vector borne diseases. First, a mathematical model is formulated to evaluate the impact of biological control of a vector borne disease "malaria" by considering larvivorous fish as a sustainable larval control method. To evaluate the potential impacts of this biological control measure on malaria transmission, we investigate the model describing the linked dynamics between the predator-prey interaction and the host-vector interaction. The dynamical behavior with all possible equilibria of the model is presented. The model also exhibits backward bifurcation phenomenon which give rise to the exis- tence of multiple endemic equilibria. The backward bifurcation phenomenon sug- gests that the reproductive number R 0 < 1 is not enough to eliminate the disease from the population under consideration. So an accurate estimation of parameters and level of control measures is important to reduce the infection prevalence of malaria in an endemic region. Our control techniques for elimination of malaria in a community suggest that the introduction of larvivorous fish can in principle have important consequence for the control of malaria but also indicate that it would require a strong predator on larval mosquitoes. Then, a new epidemic model of a vector-borne disease which has both direct and the vector mediated transmissions is considered. The model incorporates bilinear contact rates between the mosquitoes vector and the humans host populations. Using Lyapunov function theory some sufficient conditions for global stability of both the disease-free equilibrium and the endemic equilibrium are obtained. We derive the basic reproduction number R 0 iiiii and establish that the global dynamics are completely determined by the values of R 0 . For the basic reproductive number R 0 < 1, the disease free equilibrium is glob- ally asymptotically stable, while for R 0 > 1, a unique endemic equilibrium exists and is globally asymptotically stable. The model is extended to assess the impact of some control measures, by using an optimal control theory. In order to do this, first we show the existence of the control problem and then use both analytical and numerical techniques to investigate that there are cost effective control efforts for prevention of direct and indirect transmission of disease. Finally, we present complete characterization and numerical simulations of the optimal control prob- lem. In order to illustrate the overall picture of the epidemic, individuals under the optimal control and without control are shown in figures. Our theoretical results are confirmed by numerical simulations and suggest a promising way for the control of a vector borne disease.