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Temperature dependance of the anisotropy of the infrared dielectric properties and phonon-plasmon coupling in n-doped 4H-SiC
Get PDFPolarized infrared reflectivity spectroscopy was used to measure the temperature dependence of the anisotropy of the infrared dielectric properties and coupling be- tween phonon and plasmon modes in n-doped 4H-SiC. The advantage of polarized infrared spectroscopy over the commonly used Raman spectroscopy is that it en- ables dielectric, plasmonic, and transport properties to be probed along and per- pendicular to the c-axis, which is impossible with Raman spectroscopy because of its selection rules. In addition, the infrared spectrum, comparatively rare in Raman spectroscopy, can be described at high temperatures using simple classical theory, providing more precise information on the material’s properties. Analysis of the s- and p-polarized infrared reflectivity spectra of an n-doped 4H-SiC substrate shows that the strength and damping of the oscillators, the response of the bound elec- trons to infrared excitation, the effective ion mass, and the transverse frequency and anharmonicity of the phonons of n-doped 4H-SiC are temperature-sensitive and strongly anisotropic. It also shows that the plasmonic properties of n-doped 4H-SiC, namely the relaxation time and collective oscillation frequency of free electrons, are also highly anisotropic and, owing to the long relaxation time of free electrons in the direction parallel to the c-axis, only the axial longitudinal phonon-plasmon modes split into low-frequency and high-frequency modes at temperatures above 700 K
EXPLORING THE POTENTIAL OF BAYESIAN NETWORKS TO PREDICT THE WATER QUALITY OF FRESHWATER SYSTEMS BASED ON LANDSAT-REMOTELY SENSED DATA
No full textEutrophication is a worldwide environmental problem affecting many freshwater systems that are seeing an increased risks of harmful algal blooms (HABs). Water management agencies are under pressure to monitor these systems to avert the adverse impacts of HABs. Traditional monitoring programs that are based on collecting field data have become increasingly difficult to rely on given their poor spatio-temporal coverage and mounting costs. This study aims to assess the potential of using Bayesian Networks (BNs) to predict and assess HAB related water quality impairments in lakes across the contiguous United States, using remotely sensed data collected from the family of Landsat satellites. The performance of Landsat 5, 7 and 8 individual bands and band ratios was assessed for predicting Chlorophyll-a (Chl-a) concentrations and Secchi Disk Depths (SDDs). The results underscored the significant role that the Green-to-Blue ratio and the green band had when predicting Chl-a levels. Meanwhile, our results showed that the Blue-to-Red ratio and the red band were the most informative when estimating SDD levels, especially in mesotrophic, eutrophic and hypereutrophic lakes. Moreover, the results showed significant differences in model performance across trophic state and ecoregions. The performance of the discrete and hybrid Bayesian Networks were found to be largely identical for both water quality parameters. Nevertheless, the latter is preferred given that the discrete models required the discretization of all continuous variables; a process that is known to introduce errors
Municipal Authority and Environmental Governance in Lebanon
Get PDFLebanon is confronted with significant environmental challenges resulting from outdated development policies and a centralized governance structure. Municipalities, which play a vital role in local environmental governance, face obstacles such as financial constraints, political limitations, and structural inefficiencies that impede their effectiveness. While responsible for managing crucial aspects like solid waste, land use, air quality, and water resources, municipalities often grapple with insufficient resources, fragmented authority, and reliance on central government assistance. This study delves into the obstacles encountered by Lebanese municipalities and proposes strategies to bolster their involvement in environmental governance. Recommendations encompass enhancing financial independence, promoting decentralization, and fostering capacity building and collaboration among local authorities and stakeholders
Macroeconomic Effects of Food Price Shocks in the MENA Region
No full textThe global food market is complex and places several challenges for policymakers specifically the issue of sudden changes in food prices. These shifts in prices not
only challenge policymakers but also propose severe consequences for economies that
are not self-sufficient and rely on food imports to meet their food demand. Given
all the challenges, using the Structural Vector Autoregressive Model, this thesis focuses on revealing how the different macroeconomic variables of major oil-exporting
countries (Algeria, Bahrain, Libya, Oman, Qatar, Saudi Arabia, and the United
Arab Emirates) and the non-major oil-exporting countries (Jordan and Morocco)
in the MENA region respond to these types of shocks. In addition, this thesis aims
to identify ideal policies the government should implement to adjust and resist such
shocks. The findings of this paper suggest that net- food-importing and non-major
oil-exporting countries align in the direction of responses to surges in food prices.
As for the major exporting economies, the responses differ over time and by country;
however, these economies all showed the ability to absorb the severity of the shock
at higher levels than the non-major oil-exporting. As for the government responses,
the research revealed the need to tailor policies based on the specific circumstances
of each economy. Yet, sustainable agriculture practices, maintaining food reserves,
and stabilization policies are necessary for any economy
Soluble And Bound Phenols From Sumac (Rhus Coriaria) And Fennel (Foeniculum Vulgare) Seeds as Natural Antioxidants for Stabilizing Sunflower Oil in Comparison with a Synthetic Antioxidant
No full textThe soluble phenols were extracted from the seeds of sumac (Rhus coriaria L.) and fennel (Foeniculum vulgare) with 70% aqueous ethanol, and the bound phenols were liberated by alkaline hydrolysis with 2M NaOH. The soluble- and bound-phenolics fractions from sumac and fennel were added to sunflower oil at concentrations of 400 and 800 ppm. Sunflower oil (Control), the sumac- and fennel-treated samples, and sunflower oil containing 200 ppm of butylated hydroxy anisole (BHA) were stored at 60oC and the evolution of the primary and secondary lipid oxidation products was monitored for 35 days. The soluble- and bound phenols from both seeds inhibited lipid oxidation as reflected by the decrease (P<0.05) in peroxide value (PV), conjugated dienes (CD), anisidine value (AnV), and the increase in the induction period (P<0.05) as measured by the Rancimat, relative to the control, during storage. The soluble-phenolic fractions of both fennel and sumac were generally more effective in inhibiting (P<0.05) sunflower oil oxidation than their bound-phenolic counterparts. Further, both fractions of sumac exerted a more pronounced decrease (P<0.05) in AnV, CD, and PV, and an increase (P<0.05) in the induction period, relative to the control, than their fennel counterparts during storage of sunflower oil. The samples treated with an 800-ppm soluble fraction of sumac exhibited similar patterns of change in the lipid oxidation indices and the induction periods of the 200-ppm BHA-containing samples, thereby indicating the sumac soluble-phenolic fraction can substitute the synthetic BHA at the indicated levels
Between Stages and Pages: Philosophical Interventions in Sa'dallah Wannous' Theatre
No full textThis thesis examines the published works and the private library of Sa’dallah Wannous, which arrived at AUB in 2015. It does so by bridging the gap between the marginalia and penciled marks in the philosophy books he owned and read and three of his published plays. Wannous’ plays demonstrate his implementation of specific philosophical ideas on stage, such as existential and Marxist concepts, which raises an intriguing question about the relationship between the two fields, philosophy, and theatre/literature. Before 1967, Wannous was under the sway of existential philosophers, especially Sartre. He published a collection of plays that belong to the Theatre of the Absurd. However, after the 1967 Naksa, Wannous disavowed the theatre of the absurd in favor of political-revolutionary theatre and published a set of plays that reflect Marx’s influence on him. After Al-Sadat’s visit to Israel (1979) and Wannous’ failed suicide attempt, he stopped writing for 10 years, but published again a collection of plays in the 1990s, in the midst of the First Palestinian Intifada (1987). This thesis, hence, studies Wannous’ intellectual development across his life stages to explore the relationship between philosophy and theatre, and how the form of his theatre changed with the change of political events. I examine his pre-1967 absurdist play, The Glass Café (1965), his post-1967 revolutionary play, The King Is the King (1977), and his last published play, The Drunken Days (1997). I examine these plays by bridging the gap between the marginalia of the books in his private library and his plays, highlighting the philosophical influences that shaped Wannous’ intellectuality
Bridging the Semantic Gap: Tackling Contradictions in Semantic Similarity for Natural Language
No full textUnderstanding and accurately processing semantic relations is key to advancing Nat ural Language Processing (NLP). One primary semantic relation is contradictions
between sentences which play a crucial role in influencing the interpretation of other
semantic relations and are essential for several NLP tasks, such as sarcasm and
inconsistency detection. The ability to automatically detect contradictions is vital
for identifying mutually exclusive statements, thus recognizing the underlying irony
in sarcastic expressions and ensuring logical coherence in textual data. Addition ally, differentiating between various semantic relations can significantly enhance the
precision of automated systems and virtual assistants in generating contradiction free information. However, contradiction detection has often been overshadowed
within the semantic field in favor of entailment and similarity tasks. Contradictory
ideas can appear in diverse forms within sentences, making them challenging to
identify. Our research addresses this gap by developing reliable models specifically
tailored for contradiction detection. We employed extensive methodologies, includ ing data restructuring, benchmarking, and fine-tuning, achieving an accuracy of 98%
in classifying contradictions. Furthermore, we developed another model specialized
in differentiating between the three semantic relations: contradiction, similarity,
and dissimilarity, which achieved an accuracy of 97% in differentiating between
contradicting and dissimilar pairs. Leveraging these models, we discovered histori cally overlooked contradictory pairs within the Semantic Textual Similarity (STS)
benchmarks, inaccurately labeled as similar or dissimilar, which represent about a
quarter of this dataset. This mislabeling may lead to biases in how language mod els differentiate between contradicting, similar, and dissimilar pairs. Highlighting
these neglected contradicting pairs provides insights into the impact of contradic tions within the STS dataset on corresponding models. These insights confirm that
the presence of contradictions significantly affects the accuracy and effectiveness of
STS models. This thesis contributes significantly to realizing the full potential of
NLP in capturing the complexity of human communication, thereby enriching both
academic discourse and practical applications in the digital age
Self-Directed Learning Among High School Students in Lebanon
Get PDFThis thesis examines the readiness for self-directed learning (SDL) among high school students in Lebanon. By focusing on students in grades 10 through 12 across six private high schools, the study investigates individual readiness for SDL and the extent to which educational environments support such learning paradigms. The main finding reveals that students' readiness for SDL is low and significantly influenced by the level of school support provided. This study not only contributes to the academic discourse on SDL but also provides practical insights for implementing educational reforms aimed at enhancing learner autonomy and resilience. Furthermore, it highlights a negative correlation between both age and grade level with SDL readiness, challenging traditional expectations that older and more senior students would naturally be more prepared for SDL. These findings underscore the necessity for targeted educational strategies to foster a supportive environment that enhances SDL readiness at all high school levels
DEVELOPING A SUPPORT AND BEREAVEMENT BUNDLE FOR INFORMAL CAREGIVERS OF PATIENTS WITH A VENTRICULAR ASSIST DEVICE-DESTINATION THERAPY
Get PDFHeart Failure (HF) is a leading cause of mortality globally, posing significant challenges in healthcare, especially in older adults. This review explores the multifaceted impacts of ventricular assist devices (VAD) as a treatment option. The prevalence of HF and the adoption of VADs vary significantly across regions, with countries like Lebanon facing unique challenges. VADs initially used as a bridge to heart transplantation, have shifted into a long-term solution for many patients, including those ineligibles for transplant. This shift has profound implications for patient care and caregiver burden, that may affect the negatively.
The economic burden of VADs is substantial, with costs encompassing device implantation, hospitalization, and ongoing care. Caregivers of VAD patients face significant psychological and emotional stress, often leading to anxiety, depression, and socioeconomic strain. In Lebanon, the scarcity of organ donations and the high cost of VADs present additional challenges. This review also delves into the complexities of end-of-life care for VAD patients’ caregivers, underscoring the need for advanced care planning and bereavement support.
Guidelines have highlighted the importance of support and bereavement programs for VAD caregivers, as early as the decision of implantation is made, however, none of the hospitals in Lebanon have adopted one. This documents proposes a support and bereavement intervention checklist for informal caregivers, addressing the gap in the Lebanese context. By integrating cultural values and healthcare policies, the study seeks to improve the overall experience of patients and their caregivers, especially during bereavement
Using Real Time Tracking to Improve the Equipment Management System in the Operating Rooms
Get PDFEffective management of medical equipment within hospital operating rooms (ORs) is crucial for ensuring patient safety, timely surgeries, and efficient resource utilization. However, manual inventory checks often lead to misplaced or missing expensive equipment and overdue maintenance, resulting in unnecessary delays and financial losses. This project proposes the implementation of an automated equipment management system in the ORs of the American University of Beirut Medical Center (AUBMC) to address these challenges.
Drawing upon the Systems Life Cycle Model (SLCM), specifically focusing on the Analysis and Planning phases, the project aims to analyze current inventory management practices and design a comprehensive plan for the implementation of an automated system. By leveraging technology, such as radio-frequency identification (RFID) tagging and inventory tracking software, the system will streamline inventory checks, enhance equipment traceability, and facilitate maintenance scheduling.
The anticipated outcomes include significant time savings in locating and retrieving surgical equipment, improved control over inventory misplacement and loss, and enhanced management of equipment maintenance schedules. These outcomes not only contribute to operational efficiency within the ORs but also mitigate risks associated with surgical delays and financial implications for the hospital.
Through this project, AUBMC endeavors to enhance patient care quality, optimize resource utilization, and establish best practices for medical equipment management in OR settings