Congestion Control in Packet Switched Wide Area Networks using a Feedback Model

ABSTRAC

A MODEL FOR PREVENTIVE CONGESTION CONTROL MECHANISM IN ATM NETWORKS

Maximizing bandwidth utilization and providing performance guarantees, in the context of multimedia networking, are two incompatible goals. Heterogeneity of the multimedia sources calls for effective traffic control schemes to satisfy their diverse Quality of Service (Qos) requirement. These include admission control at connection set up, traffic control at the source end and efficient scheduling schemes at the switches. The emphasis in this paper is on traffic control at both connection set up and source end. A model for the Connection Admission Control (CAC) is proposed using probabilistic technique. Mathematical formulas are derived Cell Loss Probability (CLP), violation probability (PV) and cell throughput (TC). The performances at two UPC models (fluid flow and approximation) are investigated using the leaky bucket (LB) algorithm. The CLP, PV, and TC performed for different traffic sources which are characterized by their mean bit rate, peak bit rate and average number of bits generated during the burst. The results of the simulation show that the model for the Connection Admission Control (CAC) performs satisfactorily well for different traffic sources. Also, both models for the leaky bucket are almost coincident in policing the peak rate and mean rate of the source. Hence, policing effect is improved considerably using the proposed model

Pediatric cancer care in Africa: SIOP Global Mapping Program report on economic and population indicators

Introduction Inalignment with the World Health Organization (WHO) Global Initiative for Childhood Cancer (GICC), the International Society of Pediatric Oncology initiated a program to map global pediatric oncology services. As survival rates in Africa are low and data are scant, this continent was mapped first to identify areas with greatest need. Methods Beginning November 2018, an electronic survey was sent to all known stakeholders, followed by email communications and internet searches to verify data. Availability of pediatric oncologists, chemotherapy, surgical expertise, and radiotherapy was correlated with geographic region, World Bank income status, Universal Health Coverage, population < 15 and < 24 years, percentage of gross domestic product spent on healthcare, and Human Development Index (HDI). Results Responses were received from 48/54 African countries. All three treatment modalities were reportedly available in 9/48 countries, whereas seven countries reported no pediatric oncology services. Negative correlations were detected between provision of all three services and geographic region (P = 0.01), younger median population age (P = 0.002), low-income country status (P = 0.045), and lower HDI (P < 0.001). Conclusion This study provides a comprehensive overview of pediatric oncology care in Africa, emphasizing marked disparities between countries: some have highly specialized services, whereas others have no services. A long-term strategy to eliminate disparities in African pediatric cancer care should be aligned with the WHO GICC aims and facilitated by SIOP Africa. Meeting abstracts SIOP maps pediatric oncology services in Africa to address inequalities in childhood cancer services. Geel J, Ranasinghe N, Davidson A, Challinor J, Howard S, Wollaert S, Myezo K, Renner L, Hessissen L, Bouffet E. 51st Annual Congress of the International Society of Paediatric Oncology (SIOP), Lyon, France, October 2019. Pediatric Blood and Cancer Vol 66 S219-S219. Pediatric cancer care in Africa: SIOP Global Mapping Program report on economic and population indicators

WOUND-HEALING AND POTENTIAL ANTI-KELOIDAL PROPERTIES OF THE LATEX OF CALOTROPIS PROCERA (AITON) ASCLEPIADACEAE IN RABBITS.

Calotropis Procera (CP) has been used in the management of toothache, fresh skin burns, gum bleeding as well as others to make it qualify as a medicinal plant. This study was designed to assess its wound-healing property in rabbits and its potentials for anti keloidal activity.Fresh latex of Calotropis were obtained and evaluated phytochemically. Fifteen male rabbits were used and four excisional wounds were created on each rabbit. The rabbits were divided into five groups of three each. Group 1 was the negative control and received no treatment. The wounds of group 2 animals were treated with 2mL of Calotropis latex; group 3 with 2mL honey; and group 4 with a mixture of 1ml honey and 1 mL of the latex. The animals in group 5 were given 2mg triamcinolone intramuscularly. All the groups had their wounds treated daily for 21 days. The wounds’ diameters were measured on the day of wound creation, thereafter on days 7, 14 and 21 post wound creation. Biopsies of the wounds were taken on days 3 and 21 and viewed histologically. Phytochemical study of the latex revealed the presence of glycosides, tannins and alkaloids. The wounds were found to be significantly (

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p&lt;0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p&lt;0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised