Performance issues for multicore processor operating systems

In the midst of the huge development in processors industry as a response to the increasing demand for high-speed processors manufacturers were able to achieve the goal of producing the required processors, but this industry disappointed hopes, because it faced problems not amenable to solution, such as complexity, hard management and large consumption of energy. These problems forced the manufacturers to stop the focus on increasing the speed of processors and go toward parallel processing to increase performance. This eventually produced multicore processors with high-performance, if used properly. Unfortunately, until now, these processors did not use as it should be used; because of lack support of operating system and software applications. The purpose of this research is to analyze and identify the challenges faced by multicore processors operating systems

Maternal deaths in a developing country: A study from the Aga Khan University Hospital, Karachi, Pakistan 1988-1999

Objective: The maternal deaths occurring over a twelve-year period (1988-1999) in a tertiary referral center were reviewed. The purpose of the study was to assess the causes of these maternal deaths.Setting: The Aga Khan University Hospital (AKUH) Karachi, Pakistan.Methods: The medical records of maternal deaths were reviewed. These were women who had either registered for delivery at the hospital; or were referred from another hospital or from home, when an emergency developed. They were either admitted to the Medicine, Surgery and the Obstetrics and Gynaecology Departments at the hospital.Results: A total of 81 maternal deaths were identified, of which five were the registered patients. Causes of deaths were eclampsia, puerperal sepsis and pulmonary embolism. The maternal mortality ratio in the registered patients was 20 per 100,000 live births. Ninety percent of the women were between the age group of 15-35 years. Of these forty two percent were primigravidas, forty four percent of the women died due to direct causes, of which sepsis was the most common cause and accounted for twenty five percent of the total deaths. Indirect causes were responsible for 55.6% of the deaths, including hepatic failure in 21%, other infectious disease in 17% and malignancy in 5% of the cases.Conclusion: In developing countries other than obstetrical causes, infectious diseases contribute to the death of women during childbearing years. Comprehensive medical services and adequate obstetrical emergency services can lower maternal mortality rates at all levels

Evaluation of Mechanical Properties of SiC Whisker Reinforced In-Situ Composites Prepared by Carbothermal Reduction of Silicate Minerals

Al2O3-SiCx, and ZrO_-SiCx, composite powders were prepared by carbothermal reduction of alumino-silicate minerals (kaoline and silimanite) and zircon respectively. The powders were hot pressed at 175011C and 40 MPa pressure in argon atmosphere.Test specimens (4 x 6 x 30 mm3) were made out of hot pressed discs for mechanical properties evaluation. The physical properties i.e. bulk density (B.D.), apparent porosity (A.P.) were measured by Archimedes principle. Young's modulus, fracture toughness and bending strength were measured by resonance frequency response, SENB technique and 4-point bend test respectively. Mechanical properties were found to be better in the case of composites prepared from silimanite and zircon due to optimum whisker content

Single stage bilateral total hip replacement: Is it an option or a risk?

Abstract OBJECTIVE: To evaluate safety and feasibility of two-stage total hip arthroplasty and to compare it with single-stage procedure. METHODS: The retrospective study was conducted at The Aga Khan University Hospital and comprised all cases of total hip replacements between January 2001 and December 2014 that were retrieved from the database using International Classification of Diseases (9th Revision) coding. A standardised questionnaire was completed, including patient demographics, primary diagnosis, peri and postoperative morbidity and mortality. Differences among patients\\u27 data were analysed using chi square test for dichotomous variables and student t-test for continuous variables. RESULTS: Of the 48 cases, 34(71%) had single-stage bilateral total hip replacement and 14(29%) had two-stage procedure. The mean hospital stay in the single-stage group was 8.1±3.2 days compared to 19.6±5 days in the other group. The two-stage group required a significantly greater need for transfusion compared to the single-stage group (P\u3c0.05). There was no statistically significant increase in peri or postoperative complication (p\u3e 0.05). CONCLUSIONS: Simultaneous bilateral total hip arthroplasty was found to be a safe and viable option with a decreased transfusion requirement and shorter hospital stay along with no significant increase in morbidity or mortality

Microstructural Characterization of Electroformed Nickel and Its Composites

In the present work the nickel metal matrix was developed by electrochemicalforming technique, were the nickel matrix is built around the reinforced carbonfiber in various thicknesses and fiber volume fractions. The metallographicanalysis indicate that the experimental depositing condition have a dominatingeffect on the observed composite microstructure. The grain size of the depositednickel is found (from the microstructure) to vary inversely with the amount of thedepositing electrical current density. Also the temperature of the solution seem toreflect quite well on the microstructure of the metal matrix, were relatively highand low solution temperature produced rather refined grain structure, while anintermediate temperature of (50°C) is found to deposited courser grain size.Secondary thermal and mechanical treatments are found to modify themicrostructure in a way that higher annealing temperatures tend to enhanced thegrain growth process and tend to reduced apparent porosity at (650°C), similarlythe forging of the electroformed composites made at different temperature tend toreduced the internal porosity, by a notable ratio, depending on the temperature ofthe forging process