Comparitive Evaluation of Geometric Dynamic Channel Allocation Over Other Channel Allocation Schemes

Wireless services are one of the strongest growth areas in telecommunications today. Cellular voice is well established as a high-end service in most areas, but demand is increasing rapidly. In cellular systems, the geographical region is split using a regular topology, into cells each containing one base station. The base station should assign a channel that is not currently used within some specified distance. There are many kinds of channel assignment methods used in mobile communication starting with Fixed Channel Assignment (FCA), through Dynamic Channel Assignment (DCA) and Hybrid Channel Assignment (HCA). Personal Communication Services (PCS's) have been introduced as a mass-market phone service. The capacity, however, is now a critical issue for all of these services. The solution to the increasing spectrum efficiency demand in Personal Communication Services (PCS's) is the implementation of Dynamic Channel Allocation (DCA) strategy with distributed control. This thesis concentrates on one ,specific class of dynamic channel allocation called the Geometric Dynamic Channel Allocation (GDCA). The main feature of the GDCA lies in its ability to organise the dynamic resource assignment so that the resulting carrier usage pattern resembles what corresponds to other strategies , as long as that is compatible with the offered traffic pattern. Besides that, the overall performance advantage of GDCA over other strategies increases , as the offered traffic becomes larger

Epidemiology and antimicrobial resistance trends of Acinetobacter species in the United Arab Emirates: a retrospective analysis of 12 years of national AMR surveillance data

Introduction: Acinetobacter spp., in particular A. baumannii, are opportunistic pathogens linked to nosocomial pneumonia (particularly ventilator-associated pneumonia), central-line catheter-associated blood stream infections, meningitis, urinary tract infections, surgical-site infections, and other types of wound infections. A. baumannii is able to acquire or upregulate various resistance determinants, making it frequently multidrug-resistant, and contributing to increased mortality and morbidity. Data on the epidemiology, levels, and trends of antimicrobial resistance of Acinetobacter spp. in clinical settings is scarce in the Gulf Cooperation Council (GCC) and Middle East and North Africa (MENA) regions. Methods: A retrospective 12-year analysis of 17,564 non-duplicate diagnostic Acinetobacter spp. isolates from the United Arab Emirates (UAE) was conducted. Data was generated at 317 surveillance sites by routine patient care during 2010-2021, collected by trained personnel and reported by participating surveillance sites to the UAE National AMR Surveillance program. Data analysis was conducted with WHONET. Results: Species belonging to the A. calcoaceticus-baumannii complex were mostly reported (86.7%). They were most commonly isolated from urine (32.9%), sputum (29.0%), and soft tissue (25.1%). Resistance trends to antibiotics from different classes during the surveillance period showed a decreasing trend. Specifically, there was a significant decrease in resistance to imipenem, meropenem, and amikacin. Resistance was lowest among Acinetobacter species to both colistin and tigecycline. The percentages of multidrug-resistant (MDR) and possibly extensively drug-resistant (XDR) isolates was reduced by almost half between the beginning of the study in 2010 and its culmination in 2021. Carbapenem-resistant Acinetobacter spp. (CRAB) was associated with a higher mortality (RR: 5.7), a higher admission to ICU (RR 3.3), and an increased length of stay (LOS; 13 excess inpatient days per CRAB case), as compared to Carbapenem-susceptible Acinetobacter spp. Conclusion: Carbapenem-resistant Acinetobacter spp. are associated with poorer clinical outcomes, and higher associated costs, as compared to carbapenem-susceptible Acinetobacter spp. A decreasing trend of MDR Acinetobacter spp., as well as resistance to all antibiotic classes under surveillance was observed during 2010 to 2021. Further studies are needed to explore the reasons and underlying factors leading to this remarkable decrease of resistance over time

How might infant and paediatric immune responses influence malaria vaccine efficacy?

Naturally acquired immunity to malaria requires repeat infections yet does not engender sterile immunity or long-lasting protective immunologic memory. This renders infants and young children the most susceptible to malaria-induced morbidity and mortality, and the ultimate target for a malaria vaccine. The prevailing paradigm is that infants initially garner protection due to transplacentally transferred anti-malarial antibodies and other intrinsic factors such as foetal haemoglobin. As these wane infants have an insufficient immune repertoire to prevent genetically diverse Plasmodium infections and an inability to control malaria-induced immunopathology. This Review discusses humoral, cell-mediated and innate immune responses to malaria and how each contributes to protection – focusing on how deficiencies in infant and paediatric immune responses might influence malaria vaccine efficacy in this population. In addition, burgeoning evidence suggests a role for inhibitory receptors that limit immunopathology and guide the development of long-lived immunity. Precisely how age or malaria infections influence the function of these regulators is unknown. Therefore the possibility that infants may not have the immune-dexterity to balance effective parasite clearance with timely immune-regulation leading to protective immunologic memory is considered. And thus, malaria vaccines tested in adults and older children may not be predictive for trials conducted in infants

Analysis and measurement of the impact of government spending on Iraq's poverty indicators for 2004-2018

Government spending policies are one of the most prominent economic policies affecting some of the economic variables that support the economic growth process, because of their underlying impact on Iraq's long-term poverty rates and their increased impact after 2003, inter alia, on economic, social and political grounds. The research was based on the premise that despite increased spending and strategies to reduce poverty in Iraq, public spending policy suffers from distortions, inefficiencies and effectiveness as income variation increases during the research period. The research aims to analyse and measure the impacts of public spending policy on poverty trends and to clarify the most important mechanisms used, especially in Iraq after 2003, and what their economic and social implications are, as well as to establish a relationship between government spending policies and poverty indicators using a quantitative method. The study found that despite the gradual decline in poverty in Iraq from 40% in 2005 to its lowest level in 2012, which was 18.9% due to public employment and high government expenditure due to increased public revenues, it went back up almost to 24.2% in 2019&nbsp

Prevalence of Metabolic Syndrome According to Adult Treatment Panel III and International Diabetes Federation Criteria: A Population-Based Study

Objective: The objective of the study was to examine the prevalence of metabolic syndrome among adult Qatari population according to the revised criteria of the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) and the International Diabetes Federation (IDF), assess which component contributed to the increased risk of the metabolic syndrome, and identify the characteristics of the subjects with metabolic syndrome

Diabetes and Renal Transplantation: Saudi Experience

We conducted this study to evaluate the prevalence and risk factors of diabetes mellitus (DM) in our renal transplant population. We retrospectively reviewed the records of the active renal transplant patients at two large transplant centers in Riyadh and Jeddah in Saudi Arabia, transplanted between 1979 and November 1998. The recipients were grouped according to the diagnosis of diabetes; group I: diabetes developed before transplantation (BTDM), group II: diabetes developed only after transplantation (ATDM) and group III: did not have diabetes (NDM). There were 1112 patients′ records included in the study. The mean age was 38.2 years and the mean duration of transplantation was 66.9 months. There were 113(10.2%) patients in BTDM group, 134 (12.1%) patients in the ATDM group and 865 (77.8%) patients in the NDM group. There was no significant difference in the prevalence of hypertension among the study groups. In comparison to the other groups, the BTDM group had significantly more males (78.8%), more patients who were transplanted after 1990 (pre-cyclosporin era), more patients with grafts from living non-related donors (46%), higher incidence of acute rejection episodes (39%), higher mean serum creatinine and more patients treated with azathioprine (71%). The ATDM group had significantly higher mean age (46.4 years), higher mean duration of transplantation (91.5 months), higher rate of retransplantation (8.2%), higher mean serum cholesterol level (6.0mmol/L) and more frequently abnormal electrocardiogram (24.6%) than the other two groups. The ATDM group had comparable mean weight (70.2 kg) to the BTDM group but significantly higher than the NDM group (66.1kg). The NDM group had significantly higher mean dose of cyclosporine (3.3 mg/kg/day) and higher mean dose of prednisone (0.16 mg/kg/day) than the other groups. The only independent risk factor for developing DM after transplantation was advancing age. The currently used low-dose steroid therapy was not significantly associated with development of DM after renal transplantation. Nevertheless DM is an important co-morbid condition in the transplant population and is associated with increased risk for cardiovascular and cerebrovascular events