14 research outputs found
Global sensitivity analysis of parameters in Puck's failure theory for laminated composites
No full textTitle from first page of PDF file (viewed January 10, 2011)Includes bibliographical references (p. 107-110)Composite materials offer numerous advantages over traditional monolithic materials such as higher specific strength, greater specific stiffness, greater corrosion resistance and good vibration damping characteristics. Improved use of composite materials is a key element to improving energy efficiency of future plane, trains and automobiles. One of the challenges to overcome for achieving higher efficiencies with composite materials is the development of more accurate models and material parameters for composite failure prediction. There are currently over twenty failure criteria to predict failure of fiber reinforced polymer matrix composite materials. Recent assessment of failure prediction models in a worldwide failure exercise showed that the model formulated by Puck (1994) to be the most accurate. However, the Tsai-Wu criterion that was developed in the 1960 and 70s continues to be the work horse in industrial applications. Existing models fail to predict composite material failure accurately under certain loading regimes. To overcome this deficiency engineers simply choose larger safety factors that leads to heavier designs. Using a more accurate model, can allow us to decrease these safety factors and thereby achieve lighter structural designs. The recently formulated Puck's failure model provides such accuracy. However, the model requires as many as eleven material parameters. Some of these parameters require multiplicity of tests/experiments to deduce them. Obtaining material parameters from tests and quantifying their variability is a costly and time consuming exercise. Inaccurately quantified material parameters require enforcing larger safety factors in the design to safeguard for the material property data uncertainty. Gains in improving model fidelity are negated by the inaccuracy of the material parameters available. This thesis presents the results of a global variance sensitivity of material parameters needed for composite failure prediction using Puck's failure theory. Global variance sensitivities quantify the relative contribution of variances in individual material parameters to the total variance of the laminate failure load. The use of total variance sensitivity to identify optimal laminates and loading conditions needed to characterize new material properties more accurately is demonstrated
1st Author-The Effectiveness of Compensation in Maintaining Employee Retention
No full textEmployee retention is a major problem for businesses of all sizes. While there are many factors that contribute to employee retention, compensation is one of the most important. This review article examines the research on the effectiveness of compensation in maintaining employee retention. The article begins by discussing the importance of compensation in employee retention. It then reviews the research on the determinants of employee retention and the impact of compensation on employee retention. The article concludes by discussing the implications of the research for organizations. The research reviewed in this article suggests that compensation is an important factor in employee retention. Studies have shown that compensation plays a significant role in employee retention. Employees who are paid more are more likely to stay with their organizations. However, it is clear that organizations must also focus on other factors beyond compensation, including job satisfaction, work-life balance, opportunities for career development, employee engagement, recognition, and communication also play a significant role in retaining employees. Furthermore, company culture, leadership, and other benefits can also affect employee retention. Organizations can improve their employee retention rates by offering competitive compensation packages. However, it is important to remember that compensation is not the only factor that affects employee retention. Organizations seeking to improve their employee retention rates should adopt a comprehensive approach that includes competitive compensation as well as addressing other factors important to employees that value and retains top talent, leading to long-term success and sustainability.</p
4th Author-Food and Drug Safety Management in Pakistan
No full textFood and drug safety management is critical for public health in Pakistan. This paper reviews the current food and drug safety management system in Pakistan, identifies the challenges, and suggests improvement solutions. The regulatory framework for food and drug safety in Pakistan is the responsibili?ty of several federal and provincial agencies, including the Drug Regulatory Authority of Pakistan (DRAP) for drugs and the Pakistan Standards and Quality Control Authority (PSQCA) for food. However, the system faces sev?eral challenges, including weak regulatory frameworks, a lack of resources, corruption, and a lack of public awareness. The paper suggests solutions such as increased funding and staffing of regulatory agencies, the crackdown on corruption, strengthening of the regulatory framework, and public aware?ness campaigns to promote the importance of food and drug safety. The safety of food and drugs is a critical issue in Pakistan, as it has a direct impact on the health and well-being of its population. Despite significant progress made in recent years, Pakistan still faces significant challenges in ensuring that food and drugs are safe for consumption. This paper examines the cur?rent state of food and drug safety management in Pakistan, including its regu?latory framework, enforcement mechanisms, and challenges. It also provides recommendations for improving food and drug safety management in the country.</p
4th Author-Traffic Problems in Dhaka City Causes, Effects, and Solutions (Case Study to Develop a Business Model)
No full textDhaka, the capital city of Bangladesh, is facing a severe traffic problem due to the rapid growth of the city’s population and inadequate transportation infrastructure. This year, the total number of working hours lost on Dhaka’s roads has surpassed eight million per day, a significant increase compared to the five million working hours lost daily in 2017. This paper presents a comprehensive analysis of Dhaka’s traffic problem, examining the underlying causes and their implications. The analysis process involves an examination of the existing literature and data related to Dhaka’s traffic problem. The paper evaluates the historical development of the city’s transportation infrastructure and urban planning policies to understand how they have contributed to the current situation. The study also analyzes the socioeconomic factors that drive private vehicle ownership and usage in Dhaka. The lack of public transportation and the unregulated growth of private vehicles are major contributors to Dhaka’s traffic congestion. Additionally, poor road infrastructure and traffic management exacerbate the problem, leading to increased air pollution and economic costs. The paper presents a detailed analysis of these factors and their impact on the city. The paper also evaluates potential solutions to the problem, including the expansion of public transportation, the improvement of road infrastructure, the promotion of alternative modes of transport, and the implementation of better traffic management strategies. The study found that a combination of these solutions could effectively address Dhaka’s traffic problem. However, the success of these solutions requires political will and financial investment. In conclusion, the paper high?lights the urgency of addressing Dhaka’s traffic problem and emphasizes the need for comprehensive and sustainable solutions. The study provides policymakers and researchers with a framework for understanding and addressing the traffic problem in Dhaka, contributing to the ongoing discussion on how to improve the quality of life for the city’s residents.</p
Mortality, morbidity, and hospitalisations due to influenza lower respiratory tract infections, 2017 : an analysis for the Global Burden of Disease Study 2017
No full textAbstract: Background Although the burden of influenza is often discussed in the context of historical pandemics and the threat of future pandemics, every year a substantial burden of lower respiratory tract infections (LRTIs) and other respiratory conditions (like chronic obstructive pulmonary disease) are attributable to seasonal influenza. The Global Burden of Disease Study (GBD) 2017 is a systematic scientific effort to quantify the health loss associated with a comprehensive set of diseases and disabilities. In this Article, we focus on LRTIs that can be attributed to influenza. Methods We modelled the LRTI incidence, hospitalisations, and mortality attributable to influenza for every country and selected subnational locations by age and year from 1990 to 2017 as part of GBD 2017. We used a counterfactual approach that first estimated the LRTI incidence, hospitalisations, and mortality and then attributed a fraction of those outcomes to influenza. Findings Influenza LRTI was responsible for an estimated 145 000 (95% uncertainty interval [UI] 99 000-200 000) deaths among all ages in 2017. The influenza LRTI mortality rate was highest among adults older than 70 years (16.4 deaths per 100 000 [95% UI 11.6-21.9]), and the highest rate among all ages was in eastern Europe (5.2 per 100 000 population [95% UI 3.5-7.2]). We estimated that influenza LRTIs accounted for 9 459 000 (95% UI 3 709 000-22 935 000) hospitalisations due to LRTIs and 81 536 000 hospital days (24 330 000-259 851 000). We estimated that 11.5% (95% UI 10.0-12.9) of LRTI episodes were attributable to influenza, corresponding to 54 481 000 (38 465 000-73 864 000) episodes and 8 172 000 severe episodes (5 000 000-13 296 000). Interpretation This comprehensive assessment of the burden of influenza LRTIs shows the substantial annual effect of influenza on global health. Although preparedness planning will be important for potential pandemics, health loss due to seasonal influenza LRTIs should not be overlooked, and vaccine use should be considered. Efforts to improve influenza prevention measures are needed. Copyright (c) 2018 The Author(s). Published by Elsevier Ltd
Estimates of global, regional, and national incidence, prevalence, and mortality of HIV, 1980-2015 : the Global Burden of Disease Study 2015.
No full textBACKGROUND: Timely assessment of the burden of HIV/AIDS is essential for policy setting and programme evaluation. In this report from the Global Burden of Disease Study 2015 (GBD 2015), we provide national estimates of levels and trends of HIV/AIDS incidence, prevalence, coverage of antiretroviral therapy (ART), and mortality for 195 countries and territories from 1980 to 2015. METHODS: For countries without high-quality vital registration data, we estimated prevalence and incidence with data from antenatal care clinics and population-based seroprevalence surveys, and with assumptions by age and sex on initial CD4 distribution at infection, CD4 progression rates (probability of progression from higher to lower CD4 cell-count category), on and off antiretroviral therapy (ART) mortality, and mortality from all other causes. Our estimation strategy links the GBD 2015 assessment of all-cause mortality and estimation of incidence and prevalence so that for each draw from the uncertainty distribution all assumptions used in each step are internally consistent. We estimated incidence, prevalence, and death with GBD versions of the Estimation and Projection Package (EPP) and Spectrum software originally developed by the Joint United Nations Programme on HIV/AIDS (UNAIDS). We used an open-source version of EPP and recoded Spectrum for speed, and used updated assumptions from systematic reviews of the literature and GBD demographic data. For countries with high-quality vital registration data, we developed the cohort incidence bias adjustment model to estimate HIV incidence and prevalence largely from the number of deaths caused by HIV recorded in cause-of-death statistics. We corrected these statistics for garbage coding and HIV misclassification. FINDINGS: Global HIV incidence reached its peak in 1997, at 3·3 million new infections (95% uncertainty interval [UI] 3·1-3·4 million). Annual incidence has stayed relatively constant at about 2·6 million per year (range 2·5-2·8 million) since 2005, after a period of fast decline between 1997 and 2005. The number of people living with HIV/AIDS has been steadily increasing and reached 38·8 million (95% UI 37·6-40·4 million) in 2015. At the same time, HIV/AIDS mortality has been declining at a steady pace, from a peak of 1·8 million deaths (95% UI 1·7-1·9 million) in 2005, to 1·2 million deaths (1·1-1·3 million) in 2015. We recorded substantial heterogeneity in the levels and trends of HIV/AIDS across countries. Although many countries have experienced decreases in HIV/AIDS mortality and in annual new infections, other countries have had slowdowns or increases in rates of change in annual new infections. INTERPRETATION: Scale-up of ART and prevention of mother-to-child transmission has been one of the great successes of global health in the past two decades. However, in the past decade, progress in reducing new infections has been slow, development assistance for health devoted to HIV has stagnated, and resources for health in low-income countries have grown slowly. Achievement of the new ambitious goals for HIV enshrined in Sustainable Development Goal 3 and the 90-90-90 UNAIDS targets will be challenging, and will need continued efforts from governments and international agencies in the next 15 years to end AIDS by 2030.Funding: We thank the countless individuals who have contributed to the Global Burden of Disease (GBD) Study 2015 in various capacities. We specifically thank Jeffrey Eaton and John Stover. HW and CJLM received funding for this study from the Bill & Melinda Gates Foundation; the National Institute of Mental Health, National Institutes of Health (NIH; R01MH110163); and the National Institute on Aging, NIH (P30AG047845). LJAR acknowledges the support of Qatar National Research Fund (NPRP 04-924-3-251) who provided the main funding for generating the data provided to the GBD-Institute for Health Metrics and Evaluation effort. BPAQ acknowledges institutional support from PRONABEC (National Program of Scholarship and Educational Loan), provided by the Peruvian government. DB is supported by the Bill & Melinda Gates Foundation (grant number OPP1068048). JDN was supported in his contribution to this work by a Fellowship from Fundacao para a Ciencia e a Tecnologia, Portugal (SFRH/BPD/92934/2013). KD is supported by a Wellcome Trust Fellowship in Public Health and Tropical Medicine (grant number 099876). TF received financial support from the Swiss National Science Foundation (SNSF; project number P300P3-154634). AG acknowledges funding from Sistema Nacional de Investigadores de Panama-SNI. PJ is supported by Wellcome Trust-DBT India Alliance Clinical and Public Health Intermediate Fellowship. MK receives research support from the Academy of Finland, the Swedish Research Council, Alzheimerfonden, Alzheimer's Research & Prevention Foundation, Center for Innovative Medicine (CIMED) at Karolinska Institutet South Campus, AXA Research Fund, Wallenberg Clinical Scholars Award from the Knut och Alice Wallenbergs Foundation, and the Sheika Salama Bint Hamdan Al Nahyan Foundation. AK's work was supported by the Miguel Servet contract financed by the CP13/00150 and PI15/00862 projects, integrated into the National R&D&I and funded by the ISCIII (General Branch Evaluation and Promotion of Health Research), and the European Regional Development Fund (ERDF-FEDER). SML is funded by a National Institute for Health Research (NIHR) Clinician Scientist Fellowship (grant number NIHR/CS/010/014). HJL reports grants from the NIHR, EU Innovative Medicines Initiative, Centre for Strategic & International Studies, and WHO. WM is Program analyst, Population and Development, in the Peru Country Office of the United Nations Population Fund, which does not necessarily endorse this study. For UOM, funding from the German National Cohort Consortium (O1ER1511D) is gratefully acknowledged. KR reports grants from NIHR Oxford Biomedical Research Centre, NIHR Career Development Fellowship, and Oxford Martin School during the conduct of the study. GR acknowledges that work related to this paper has been done on the behalf of the GBD Genitourinary Disease Expert Group supported by the International Society of Nephrology (ISN). ISS reports grants from FAPESP (Brazilian public agency). RSS receives institutional support from Universidad de Ciencias Aplicadas y Ambientales, UDCA, Bogota Colombia. SS receives postdoctoral funding from the Fonds de la recherche en sante du Quebec (FRSQ), including its renewal. RTS was supported in part by grant number PROMETEOII/2015/021 from Generalitat Valenciana and the national grant PI14/00894 from ISCIII-FEDER. PY acknowledges support from Strategic Public Policy Research (HKU7003-SPPR-12).</p
Mortality, morbidity, and hospitalisations due to influenza lower respiratory tract infections, 2017: an analysis for the Global Burden of Disease Study 2017
No full textTroeger CE, Blacker BF, Khalil IA, et al. Mortality, morbidity, and hospitalisations due to influenza lower respiratory tract infections, 2017: an analysis for the Global Burden of Disease Study 2017. LANCET RESPIRATORY MEDICINE. 2019;7(1):69-89.Background Although the burden of influenza is often discussed in the context of historical pandemics and the threat of future pandemics, every year a substantial burden of lower respiratory tract infections (LRTIs) and other respiratory conditions (like chronic obstructive pulmonary disease) are attributable to seasonal influenza. The Global Burden of Disease Study (GBD) 2017 is a systematic scientific effort to quantify the health loss associated with a comprehensive set of diseases and disabilities. In this Article, we focus on LRTIs that can be attributed to influenza.
Methods We modelled the LRTI incidence, hospitalisations, and mortality attributable to influenza for every country and selected subnational locations by age and year from 1990 to 2017 as part of GBD 2017. We used a counterfactual approach that first estimated the LRTI incidence, hospitalisations, and mortality and then attributed a fraction of those outcomes to influenza.
Findings Influenza LRTI was responsible for an estimated 145 000 (95% uncertainty interval [UI] 99 000-200 000) deaths among all ages in 2017. The influenza LRTI mortality rate was highest among adults older than 70 years (16.4 deaths per 100 000 [95% UI 11.6-21.9]), and the highest rate among all ages was in eastern Europe (5.2 per 100 000 population [95% UI 3.5-7.2]). We estimated that influenza LRTIs accounted for 9 459 000 (95% UI 3 709 000-22 935 000) hospitalisations due to LRTIs and 81 536 000 hospital days (24 330 000-259 851 000). We estimated that 11.5% (95% UI 10.0-12.9) of LRTI episodes were attributable to influenza, corresponding to 54 481 000 (38 465 000-73 864 000) episodes and 8 172 000 severe episodes (5 000 000-13 296 000).
Interpretation This comprehensive assessment of the burden of influenza LRTIs shows the substantial annual effect of influenza on global health. Although preparedness planning will be important for potential pandemics, health loss due to seasonal influenza LRTIs should not be overlooked, and vaccine use should be considered. Efforts to improve influenza prevention measures are needed. Copyright (c) 2018 The Author(s). Published by Elsevier Ltd
Global, regional, and national incidence, prevalence, and mortality of HIV, 1980-2017, and forecasts to 2030, for 195 countries and territories: a systematic analysis for the Global Burden of Diseases, Injuries, and Risk Factors Study 2017
No full textBackground Understanding the patterns of HIV/AIDS epidemics is crucial to tracking and monitoring the progress of prevention and control efforts in countries. We provide a comprehensive assessment of the levels and trends of HIV/AIDS incidence, prevalence, mortality, and coverage of antiretroviral therapy (ART) for 1980-2017 and forecast these estimates to 2030 for 195 countries and territories. Methods We determined a modelling strategy for each country on the basis of the availability and quality of data. For countries and territories with data from population-based seroprevalence surveys or antenatal care clinics, we estimated prevalence and incidence using an open-source version of the Estimation and Projection Package-a natural history model originally developed by the UNAIDS Reference Group on Estimates, Modelling, and Projections. For countries with cause-specific vital registration data, we corrected data for garbage coding (ie, deaths coded to an intermediate, immediate, or poorly defined cause) and HIV misclassification. We developed a process of cohort incidence bias adjustment to use information on survival and deaths recorded in vital registration to back-calculate HIV incidence. For countries without any representative data on HIV, we produced incidence estimates by pulling information from observed bias in the geographical region. We used a re-coded version of the Spectrum model (a cohort component model that uses rates of disease progression and HIV mortality on and off ART) to produce age-sex-specific incidence, prevalence, and mortality, and treatment coverage results for all countries, and forecast these measures to 2030 using Spectrum with inputs that were extended on the basis of past trends in treatment scale-up and new infections. Findings Global HIV mortality peaked in 2006 with 1.95 million deaths (95 uncertainty interval 1.87-2.04) and has since decreased to 0.95 million deaths (0.91-1.01) in 2017. New cases of HIV globally peaked in 1999 (3.16 million, 2.79-3.67) and since then have gradually decreased to 1.94 million (1.63-2.29) in 2017. These trends, along with ART scale-up, have globally resulted in increased prevalence, with 36.8 million (34.8-39.2) people living with HIV in 2017. Prevalence of HIV was highest in southern sub-Saharan Africa in 2017, and countries in the region had ART coverage ranging from 65.7 in Lesotho to 85.7 in eSwatini. Our forecasts showed that 54 countries will meet the UNAIDS target of 81 ART coverage by 2020 and 12 countries are on track to meet 90 ART coverage by 2030. Forecasted results estimate that few countries will meet the UNAIDS 2020 and 2030 mortality and incidence targets. Interpretation Despite progress in reducing HIV-related mortality over the past decade, slow decreases in incidence, combined with the current context of stagnated funding for related interventions, mean that many countries are not on track to reach the 2020 and 2030 global targets for reduction in incidence and mortality. With a growing population of people living with HIV, it will continue to be a major threat to public health for years to come. The pace of progress needs to be hastened by continuing to expand access to ART and increasing investments in proven HIV prevention initiatives that can be scaled up to have population-level impact. Copyright (C) 2019 The Author(s). Published by Elsevier Ltd
Global, regional, national, and selected subnational levels of stillbirths, neonatal, infant, and under‐5 mortality during 1980‐2015 : a systematic analysis for the Global Burden of Disease Study 2015
No full textBackground
Established in 2000, Millennium Development Goal 4 (MDG4) catalysed extraordinary political, financial, and social commitments to reduce under-5 mortality by two-thirds between 1990 and 2015. At the country level, the pace of progress in improving child survival has varied markedly, highlighting a crucial need to further examine potential drivers of accelerated or slowed decreases in child mortality. The Global Burden of Disease 2015 Study (GBD 2015) provides an analytical framework to comprehensively assess these trends for under-5 mortality, age-specific and cause-specific mortality among children under 5 years, and stillbirths by geography over time.
Methods
Drawing from analytical approaches developed and refined in previous iterations of the GBD study, we generated updated estimates of child mortality by age group (neonatal, post-neonatal, ages 1–4 years, and under 5) for 195 countries and territories and selected subnational geographies, from 1980–2015. We also estimated numbers and rates of stillbirths for these geographies and years. Gaussian process regression with data source adjustments for sampling and non-sampling bias was applied to synthesise input data for under-5 mortality for each geography. Age-specific mortality estimates were generated through a two-stage age–sex splitting process, and stillbirth estimates were produced with a mixed-effects model, which accounted for variable stillbirth definitions and data source-specific biases. For GBD 2015, we did a series of novel analyses to systematically quantify the drivers of trends in child mortality across geographies. First, we assessed observed and expected levels and annualised rates of decrease for under-5 mortality and stillbirths as they related to the Soci-demographic Index (SDI). Second, we examined the ratio of recorded and expected levels of child mortality, on the basis of SDI, across geographies, as well as differences in recorded and expected annualised rates of change for under-5 mortality. Third, we analysed levels and cause compositions of under-5 mortality, across time and geographies, as they related to rising SDI. Finally, we decomposed the changes in under-5 mortality to changes in SDI at the global level, as well as changes in leading causes of under-5 deaths for countries and territories. We documented each step of the GBD 2015 child mortality estimation process, as well as data sources, in accordance with the Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER).
Findings
Globally, 5·8 million (95% uncertainty interval [UI] 5·7–6·0) children younger than 5 years died in 2015, representing a 52·0% (95% UI 50·7–53·3) decrease in the number of under-5 deaths since 1990. Neonatal deaths and stillbirths fell at a slower pace since 1990, decreasing by 42·4% (41·3–43·6) to 2·6 million (2·6–2·7) neonatal deaths and 47·0% (35·1–57·0) to 2·1 million (1·8-2·5) stillbirths in 2015. Between 1990 and 2015, global under-5 mortality decreased at an annualised rate of decrease of 3·0% (2·6–3·3), falling short of the 4·4% annualised rate of decrease required to achieve MDG4. During this time, 58 countries met or exceeded the pace of progress required to meet MDG4. Between 2000, the year MDG4 was formally enacted, and 2015, 28 additional countries that did not achieve the 4·4% rate of decrease from 1990 met the MDG4 pace of decrease. However, absolute levels of under-5 mortality remained high in many countries, with 11 countries still recording rates exceeding 100 per 1000 livebirths in 2015. Marked decreases in under-5 deaths due to a number of communicable diseases, including lower respiratory infections, diarrhoeal diseases, measles, and malaria, accounted for much of the progress in lowering overall under-5 mortality in low-income countries. Compared with gains achieved for infectious diseases and nutritional deficiencies, the persisting toll of neonatal conditions and congenital anomalies on child survival became evident, especially in low-income and low-middle-income countries. We found sizeable heterogeneities in comparing observed and expected rates of under-5 mortality, as well as differences in observed and expected rates of change for under-5 mortality. At the global level, we recorded a divergence in observed and expected levels of under-5 mortality starting in 2000, with the observed trend falling much faster than what was expected based on SDI through 2015. Between 2000 and 2015, the world recorded 10·3 million fewer under-5 deaths than expected on the basis of improving SDI alone
