Guest Editorial: Nonlinear Optimization of Communication Systems

Linear programming and other classical optimization techniques have found important applications in communication systems for many decades. Recently, there has been a surge in research activities that utilize the latest developments in nonlinear optimization to tackle a much wider scope of work in the analysis and design of communication systems. These activities involve every “layer” of the protocol stack and the principles of layered network architecture itself, and have made intellectual and practical impacts significantly beyond the established frameworks of optimization of communication systems in the early 1990s. These recent results are driven by new demands in the areas of communications and networking, as well as new tools emerging from optimization theory. Such tools include the powerful theories and highly efficient computational algorithms for nonlinear convex optimization, together with global solution methods and relaxation techniques for nonconvex optimization

Likelihood of rising stroke in populace of western India: a case control study

Background: Cerebrovascular accident (Stroke) is a non-communicable disease of increasing importance. According to the World Health Organization, 15 million people suffer from stroke worldwide each year. The National Commission on Macroeconomics and Health, India, has estimated 1.67 million stroke cases in India. Due to the increasing prevalence of hypertension, diabetes, dyslipidemia, fast changing lifestyle and re-structuring of population, stroke will be an epidemic in India in the days to come. Few studies have been carried out in developing countries like India. So, this study intended to know the presentation in addition to risk factors, patterns of warning signs and symptoms of stroke in patients admitted to state tertiary care Hospital. Methods: Assuming the power ratio of the number of controls same as numbers of cases specifying values for two sided confidence level 95% and odd ratio 2.15 which was the minimum risk factor in previous study was taken to calculate sample size. Results: After studying of 148 cases of stroke and same controls, we conclude that most common type of stroke is ischemic stroke followed by haemorrhagic stroke. After multivariate analysis we found, modifiable risk factors were mainly mental stress, active and passive smoking, hypertension and obesity. Conclusions: Due to the sheer magnitude, devastating consequences and residual sequelae of the stroke, early intervention in the form of patient education, modification of the lifestyle, non-pharmacological and pharmacological interventions for modifiable risk factors should be an integral aspect of patient care

Effects of kink and flexible hinge defects on mechanical responses of short double stranded DNA molecules

We predict various detectable mechanical responses to the presence of local DNA defects which are defined as short DNA segments exhibiting mechanical properties obviously different from the 50 nm persistence length based semiflexible polymer model. The defects discussed are kinks and flexible hinges either permanently fixed on DNA or thermally excited. Their effects on extension shift, the effective persistence length, the end-to-end distance distribution, and the cyclization probability are computed using a transfer-matrix method. Our predictions will be useful in future experimental designs to study DNA nicks or mismatch base pairs, mechanics of specific DNA sequences, and specific DNA-protein interaction using magnetic tweezer, fluorescence resonance energy transfer or plasmon resonance technique, and the traditional biochemistry cyclization probability measurements.Comment: 9 pages with 9 figures. Theoretical calculation based on transfer matrix. Minor updates, a new figure and more discussions are adde

Infant Mortality Trends Among Georgia Residents, 1995-2003: Targeting Healthy People’s 2010 Goals

Population-based trends in infant mortality among Georgia Residents between 1995 and 2003 were assessed on characteristics such as race, birth weight, neonatal and post-neonatal periods, and cause of death. A statistical analysis was conducted to show that the Georgia infant mortality rate (IMR) remained constant throughout the study period and averaged 8.67 per 1,000 live births. The analysis revealed racial disparities, with an IMR ranging from 6.03 in white infants to 13.76 in black infants, with less than one percent (0.86%) change, on average, among the differences between black and white mortality rates across the nine-year period. The disparities were also evident in infants with low birth weight (LBW) and very low birth weight (VLBW). Black infants born with LBW (12.9%) and VLBW (9.98%) have more than twice the rate of infant mortality compared to white infants born with LBW (6.64%) and VLBW (1.12%). Mortality in the neonatal period accounted for more than half (67.96%) of all infant deaths and exhibited considerable ethnic differences. Among all groups, black male neonates (10.7) have the highest mortality rates. The average neonatal mortality rate across the entire study period is 5.89 (SD=0.20); the average postneonatal mortality rate across the entire study period is 2.78 (SD=0.22). The five leading causes of death among Georgian infants in descending order were: birth defects, prematurity and low birth weight, Sudden Unexplained Infant Deaths (SUID), other perinatal conditions and respiratory conditions with racial differences in the ordering

Sociocultural Learning: A Perspective on GSS-Enabled Global Education

Virtual teams are rapidly developing in organisations of the new economy. As educators, we have a responsibility to ensure that our students are appropriately prepared for work in the virtual workspace, where teams may cross time, geographical, and cultural boundaries. In this article, the culturally sensitive theory of sociocultural learning is combined with GSS (Group Support Systems) in an illustration of how cross-cultural, globally distributed virtual teams of students located in The Netherlands, Greece, and Hong Kong work on vested interest projects. Finally, a set of critical success factors that inform virtual learning contexts is derived from our findings and recommendations are made for operational practice in the virtual work space

Management Forecast Quality and Capital Investment Decisions

Corporate investment decisions require managers to forecast expected future cash flows from potential investments. Although these forecasts are a critical component of successful investing, they are not directly observable by external stakeholders. In this study, we investigate whether the quality of managers' externally reported earnings forecasts can be used to infer the quality of their corporate investment decisions. Relying on the intuition that managers draw on similar skills when generating external earnings forecasts and internal payoff forecasts for their investment decisions, we predict that managers with higher quality external earnings forecasts make better investment decisions. Consistent with our prediction, we find that forecasting quality is positively associated with the quality of both acquisition and capital expenditure decisions. Our evidence suggests that externally observed forecasting quality can be used to infer the quality of capital budgeting decisions within firms

Student E-Learning Intrinsic Motivation: A Qualitative Analysis

In the age of life-long learning and increased competition for time, motivation becomes a salient issue. Students need to be more intrinsically motivated in the absence of more formal structure. This is especially true in online learning environments where direct instructor influence is mitigated. Online learning environments typically embrace many choices in ways in which learning material is presented and interaction with students is supported in both individual and collaborative contexts. As such, it is imperative that we better understand the implications of various learning activities and associated technologies on aspects of intrinsic motivation in e-learning. In this paper we examine these effects through qualitative analysis of semi-structured interviews with students in an online MBA program. Results encourage use of a pedagogically driven portfolio of learning activities supported by well-selected and integrated audio, video, and data technologies. Extension to use of mobile devices in ubiquitous e-learning contexts is explored