Most Popular Books by Omar Mohamed

A National Book Award Finalist, this remarkable graphic novel is about growing up in a refugee camp, as told by a former Somali refugee to the Newbery Honor-winning creator of Roller Girl. Omar and his younger brother, Hassan, have spent most of their lives in Dadaab, a refugee camp in Kenya. Life is hard there: never enough food, achingly dull, and without access to the medical care Omar knows his nonverbal brother needs. So when Omar has the opportunity to go to school, he knows it might be a chance to change their future . . . but it would also mean leaving his brother, the only family member he has left, every day. Heartbreak, hope, and gentle humor exist together in this graphic novel about a childhood spent waiting, and a young man who is able to create a sense of family and home in the most difficult of settings. It''s an intimate, important, unforgettable look at the day-to-day life of a refugee, as told to New York Times Bestselling author/artist Victoria Jamieson by Omar Mohamed, the Somali man who lived the story.

The United States faces major challenges in dealing with Iran, the threat of terrorism, and the tide of political instability in the Arabian Peninsula. The presence of some of the world’s largest reserves of oil and natural gas, vital shipping lanes, and Shia populations throughout the region have made the peninsula the focal point of US and Iranian strategic competition. Moreover, large youth populations, high unemployment rates, and political systems with highly centralized power bases have posed other economic, political, and security challenges that the Gulf states must address and that the United States must take into consideration when forming strategy and policy.

"This book, "Infectious Agents in Ophthalmology: Clinical Perspectives," will serves as a timely and essential resource for both clinicians and medical student, It compiles the latest insights and findings on various infectious agents, ranging from bacteria and viruses to fungi and parasites, each of which poses unique challenges in diagnosis and management. The contributions from esteemed experts in the field offer a comprehensive overview. The integration of clinical perspectives throughout thee chapters not only enhances our understanding of these infections but also emphasizes the importance of a multidisciplinary approach in managing patients. The book highlights the need for vigilance, timely intervention, and the application of emerging technologies in diagnosis and treatment, ensuring that we are well-equipped to tackle the evolving landscape of Ophthalmology infections.

Victoria Jamieson, ganadora de la Medalla Newbery de las bibliotecas de EE. UU, se hizo voluntaria tras ver por televisión las terribles circunstancias de los refugiados sirios. En este voluntariado conoció a Omar Mohamed, quien le contó su propia vivencia en un campo de la ONU en Kenia. Este libro cuenta su historia.

Motion and action prediction is a crucial component of autonomous systems and robotics. This component is vital for accidents predictions or prevention, motion planning, surveillance systems and behavior analysis. Typically, the problem involves the observation of multiple agents’ motion or actions across a span of time then predict the future motion and actions. Classical approaches which are model based failed in the complex situations that require a proper modeling of the interactions between the agents. Data driven approaches, specifically deep learning ones, had a better performance in modeling these interactions. Yet, these deep models were using classical deep learning techniques, such as recurrent and convolutional architectures. These approaches are not representative of the spatial and temporal aspects of the observations. This dissertation presents novel approaches using spatio-temporal graphs to model the observations. We model each agent as a graph node and define their spatial configuration by using the graph edges. For the temporal relationship, we represent it by propagating the graph nodes across time. This representation is powerful in capturing the spatial and temporal relationships in comparison with prior methods. Also, several deep architectures based on graph convolutional neural networks were investigated. These architectures were explored from different perspectives, such as the kernel function of the graph edges and the embedding representation of the spatio-temporal relationships in both observations and predictions. Also, the proposed models are shown to have real run-time capabilities in comparison with prior methods. Besides, the shortcomings of current evaluation metrics in assessing the quality of motion prediction models were investigated in which new metrics were proposed

Simulation of sunburn reaction has been used as a model of skin inflammation. In this context, skin innervation has been shown to play an important role in mo dulating the inflammatory reaction in the skin. The aim of this study is to gain insight into the role of cutaneous sensory innervation during acute and chronic inflammatory resp onses induced by UV. Sunlamps emitting mainly midrange UV radiation (UVB) have been implemented extensively to study skin injury in animal models due to their ease of use and effectiveness. Increased pain sensitivity and upregulation of pro-inflammato ry cytokines characterize most inflammatory responses. Release of neuropeptides by the primary afferent fibers innervating the inflamed area modulates such response an d thus the process is referred as neurogenic inflammation. In this study, a rat model was designed to assess the effect of localized UVB exposure (250 mj/cm2) on the nociceptive response and release of proinflammatory cytokines. In addition, SKH/1 hr hairless mice were used for chronic UVB irradia tion with a dose of 180 mj/cm2 three times per week for two consecutive weeks and carefully observed for the induction of skin tumors. This work showed a biphasic hyperalgesia with an early phase (1-3h) after the exposure and a late phase (48h) restricted to the irradiated paw only. The decre ase in pain thresholds upon thermal stimulation were not observed after the ablation of the capsaicin sensitive primary afferents (CSPA-fibers). However, the animals show increased sensitivity to non-noxious mechanical and cold stimuli. Chronic UVB treatment resulted in the formation of epidermal skin tumors as compared to control mice. Selective ablation of CSPA fibers reduced the incidenc e of skin lesions. These results demonstrate a key role of cutaneous sensory nerves in acute and chronic inflammatory reactions induced by UVB exposure.

Several studies were undertaken by various investigators during the last five decades to better understand the engineering behaviour of unsaturated soils. These studies are justified as more than 33% of soils worldwide are found in either arid or semi-arid regions with evaporation losses exceeding water infiltration. Due to this reason, the natural ground water table in these regions is typically at a greater depth and the soil above it is in a state of unsaturated conditions. Foundations of structures such as the housing subdivisions, multi-storey buildings, bridges, retaining walls, silos, and other infrastructure constructed in these regions in sandy soils are usually built within the unsaturated zone (i.e., vadose zone). Limited studies are reported in the literature to understand the influence of capillary stresses (i.e., matric suction) on the bearing capacity, settlement and liquefaction potential of unsaturated sands. The influence of matric suction in the unsaturated zone of the sandy soils is ignored while estimating or evaluating bearing capacity, settlement and liquefaction resistance in conventional engineering practice. The focus of the research presented in the thesis has been directed towards better understanding of these aspects and providing rational and yet simple tools for the design of shallow foundations (i.e., footings) in sands under both static and dynamic loading conditions. Terzaghi (1943) or Meyerhof (1951) equations for bearing capacity and Schmertmann et al. (1978) equation for settlement are routinely used by practicing engineers for sandy soils based on saturated soil properties. The assumption of saturated conditions leads to conservative estimates for bearing capacity; however, neglecting the influence of capillary stresses contributes to unreliable estimates of settlement or differential settlement of footings in unsaturated sands. There are no studies reported in the literature on how capillary stresses influence liquefaction, bearing capacity and settlement behavior in earthquake prone regions under dynamic loading conditions. An extensive experimental program has been undertaken to study these parameters using several specially designed and constructed equipment at the University of Ottawa. The influence of matric suction, confinement and dilation on the bearing capacity of model footings in unsaturated sand was determined using the University of Ottawa Bearing Capacity Equipment (UOBCE-2011). Several series of plate load tests (PLTs) were carried out on a sandy soil both under saturated and unsaturated conditions. Based on these studies, a semi-empirical equation has been proposed for estimating the variation of bearing capacity with respect to matric suction. The saturated shear strength parameters and the soil water characteristic curve (SWCC) are required for using the proposed equation. This equation is consistent with the bearing capacity equation originally proposed by Terzaghi (1943) and later extended by Meyerhof (1951) for saturated soils. Chapter 2 provides the details of these studies. The cone penetration test (CPT) is conventionally used for estimating the bearing capacity of foundations because it is simple and quick, while providing continuous records with depth. In this research program, a cone penetrometer was specially designed to investigate the influence of matric suction on the cone resistance in a controlled laboratory environment. Several series of CPTs were conducted in sand under both saturated and unsaturated conditions. Simple correlations were proposed from CPTs data to relate the bearing capacity of shallow foundations to cone resistance in saturated and unsaturated sands. The details of these studies are presented and summarized in Chapter 3. Standard penetration tests (SPTs) and PLTs were conducted in-situ sand deposit at Carp region in Ottawa under both saturated and unsaturated conditions. The test results from the SPTs and PLTs at Carp were used along with other data from the literature for developing correlations for estimating the bearing capacity of both saturated and unsaturated sands. The proposed SPT-CPT-based technique is simple and reliable for estimation of the bearing capacity of footings in sands. Chapter 4 summarizes the details of these investigations. Empirical relationships were proposed using the CPTs data to estimate the modulus of elasticity of sands for settlement estimation of footings in both saturated and unsaturated sands. This was achieved by modifying the Schmertmann et al. (1978) equation, which is conventionally used for settlement estimations in practice. Comparisons are provided between the three CPT-based methods that are commonly used for settlement estimations in practice and the proposed method for seven large scale footings in sandy soils. The results of the comparisons show that the proposed method provides better estimations for both saturated and unsaturated sands. Chapter 5 summarizes the details of these studies. A Flexible Laminar Shear Box (FLSB of 800-mm3 in size) was specially designed and constructed to simulate and better understand the behaviour of model surface footing under seismic loads taking account of the influence of matric suction in an unsaturated sandy soil. The main purpose of using the FLSB is to simulate realistic in-situ soils behaviour during earthquake ground shaking. The FLSB test setup with model footing was placed on unidirectional 1-g shake table (aluminum platform of 1000-mm2 in size) during testing. The resistance of unsaturated sand to deformations and liquefaction under seismic loads was investigated. The results of the study show that matric suction offers significant resistance to liquefaction and settlement of footings in sand. Details of the equipment setup, test procedure and results of this study are presented in Chapter 6. Simple techniques are provided in this thesis for estimating the bearing capacity and settlement behaviour of sandy soils taking account of the influence of capillary stresses (i.e., matric suction). These techniques are consistent with the methods used in conventional geotechnical engineering practice. The studies show that even low values of capillary stresses (i.e., 0 to 5 kPa) increases the bearing capacity by two to four folds, and the settlement of footings not only decreases significantly but also offers resistance to liquefaction in sands. These studies are promising and encouraging to use ground improvement techniques; such as capillary barrier techniques to maintain capillary stresses within the zone of influence below shallow foundations. Such techniques, not only contribute to the increase of bearing capacity, they reduce settlement and alleviate problems associated with earthquake effects in sandy soils.

Image-based modeling and simulation has become an important analytic and predictive tool for patient-specific medical applications, including large-scale in silico patient studies, optimized medical device design, and custom surgical guides and implants via additive manufacturing. The pipeline for patient-specific modeling and simulation is: image acquisition, image segmentation, surface generation, mesh generation, physics-based modeling and simulation, and clinical application. This research establishes a semi-automatic workflow for these steps, which includes a novel image-based meshing tool Shabaka. The toolchain is demonstrated by modeling the mechanics of a beating human heart based on magnetic resonance imaging (MRI) data. The Shabaka workflow ensures robust execution of each step of the pipeline. Medical images are processed and segmented using thresholding, region-growing, and manual techniques. Watertight surface meshes are extracted from image masks using a novel Voronoi-based algorithm. For scientific computing purposes, surface meshes are supplied either to tetrahedral meshing routines for conventional finite element approaches, or to a robust polyhedral mesh generation tool for a novel polyhedral finite element approach. A polyhedral finite element code is explored, that retains most of the favorable properties of conventional finite element methods, while reducing the system size by up to an order of magnitude compared to conventional techniques for the same input surface. In conjunction with a cardiac simulation code, the workflow is utilized to model finite-deformation cardiac mechanics. A quadratic tetrahedral mesh is generated from MRI data of the human heart ventricles. The constitutive law is comprised of an incompressible orthotropic hyperelastic stress response for the myocardium, plus an electrical activation-dependent active stress for the muscle fibers. Muscle fiber orientations are generated using a rule-based approach. Electrical activation times are read from a coupled electrophysiology code. A lumped circulatory model is used to impose time-dependent ventricular volume constraints. Simulation results are presented. The same mechanics are also implemented for the polyhedral finite element mesh, and preliminary verification results are presented. The toolchain used in performing image-based cardiac mechanics simulations makes important improvements to the speed and robustness of image-based modeling techniques. As efforts continue to mature, so too does the promise for simulation to impact and improve healthcare.