Ozone: Efficient Execution with Zero Timing Leakage for Modern Microarchitectures

Time variation during program execution can leak sensitive information. Time variations due to program control flow and hardware resource contention have been used to steal encryption keys in cipher implementations such as AES and RSA. A number of approaches to mitigate timing-based side-channel attacks have been proposed including cache partitioning, control-flow obfuscation and injecting timing noise into the outputs of code. While these techniques make timing-based side-channel attacks more difficult, they do not eliminate the risks. Prior techniques are either too specific or too expensive, and all leave remnants of the original timing side channel for later attackers to attempt to exploit. In this work, we show that the state-of-the-art techniques in timing side-channel protection, which limit timing leakage but do not eliminate it, still have significant vulnerabilities to timing-based side-channel attacks. To provide a means for total protection from timing-based side-channel attacks, we develop Ozone, the first zero timing leakage execution resource for a modern microarchitecture. Code in Ozone execute under a special hardware thread that gains exclusive access to a single core's resources for a fixed (and limited) number of cycles during which it cannot be interrupted. Memory access under Ozone thread execution is limited to a fixed size uncached scratchpad memory, and all Ozone threads begin execution with a known fixed microarchitectural state. We evaluate Ozone using a number of security sensitive kernels that have previously been targets of timing side-channel attacks, and show that Ozone eliminates timing leakage with minimal performance overhead

Leveraging Processor Features for System Security

Errors in hardware and software lead to vulnerabilities that can be exploited by attackers. Proposed exploit mitigation techniques can be broadly categorized into two: software-only techniques and techniques that propose specialized hardware extensions. Software-only techniques can be implemented on existing hardware, but typically suffer from impractically high overheads. On the other hand, specialized hardware extensions, while improving performance, in practice require a long time to be incorporated into production hardware. In this dissertation, we propose adapting existing processor features to provide novel and low-overhead security solutions. In the first part of the dissertation, we show how modern hardware features can be used to provide efficient memory safety. One component of memory safety that has become important in recent years is temporal memory safety. Temporal memory safety techniques are used to detect memory errors such as use-after-free errors. This dissertation proposes a temporal memory safety technique that takes advantage of pointer authentication hardware to significantly reduce the memory and runtime overhead of traditional temporal safety techniques. Providing complete memory safety on resource constrained devices is expensive, therefore we propose software-based fault isolation (sandboxing) as an efficient alternative to constrain attackers’ access to code and data in embedded systems. We show how we can use the memory protection unit (MPU) hardware available in many embedded devices along with a small trusted runtime to build a low-overhead sandboxing mechanism. In the second part of the dissertation, we show how hardware performance counters in modern processors can be used to detect rowhammer attacks. Our technique detects rowhammer attacks by monitoring for high locality memory accesses out of the last-level cache using hardware performance counters. The technique accurately detects rowhammer attacks with a low performance overhead and without requiring hardware modifications.PHDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/149852/1/zaweke_1.pd

Dietary Diversity and Meal Frequency Practices among Infant and Young Children Aged 6–23 Months in Ethiopia: A Secondary Analysis of Ethiopian Demographic and Health Survey 2011

Background. Appropriate complementary feeding practice is essential for growth and development of children. This study aimed to assess dietary diversity and meal frequency practice of infants and young children in Ethiopia. Methods. Data collected in the Ethiopian Demographic and Health Survey (EDHS) from December 2010 to June 2011 were used for this study. Data collected were extracted, arranged, recoded, and analyzed by using SPSS version 17. A total of 2836 children aged 6–23 months were used for final analysis. Both bivariate and multivariate analysis were done to identify predictors of feeding practices. Result. Children with adequate dietary diversity score and meal frequency were 10.8% and 44.7%, respectively. Children born from the richest households showed better dietary diversity score (OR = 0.256). Number of children whose age less than five years was important predictor of dietary diversity (OR = 0.690). Mothers who had exposure to media were more likely to give adequate meal frequency to their children (OR = 0.707). Conclusion. Dietary diversity and meal frequency practices were inadequate in Ethiopia. Wealth quintile, exposure to media, and number of children were affecting feeding practices. Improving economic status, a habit of eating together, and exposure to media are important to improve infant feeding practices in Ethiopia

Magnitude and causes of first-line antiretroviral therapy regimen changes among HIV patients in Ethiopia : a systematic review and meta-analysis

Background: Antiretroviral therapy (ART) has markedly decreased the morbidity and mortality due to HIV/AIDS. ART regimen change is a major challenge for the sustainability of human immunodeficiency virus (HIV) treatment program. This is found to be a major concern among HIV/AIDS patients in a resource-limited setting, where treatment options are limited. Objectives: The aim of this review is to generate the best available evidence regarding the magnitude of first-line antiretroviral therapy regimen change and the causes for regimen change among HIV patients on ART in Ethiopia. Methods: The reviewed studies were accessed through electronic web-based search strategy from PubMed Medline, EMBASE, Hinari, Springer link and Google Scholar. Data were extracted using Microsoft Excel and exported to Stata software version 13 for analyses. The overall pooled estimation of outcomes was calculated using a random-effect model of DerSimonian-Laird method at 95% confidence level. Heterogeneity of studies was determined using I2 statistics. For the magnitude of regimen change, the presence of publication bias was evaluated using the Begg's and Egger's tests. The protocol of this systematic review and meta-analysis was registered in the Prospero database with reference number ID: CRD42018099742. The published methodology is available from: https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=99742. Results: A total of 22 studies published between the years 2012 and 2018 were included. Out of 22 articles, 14 articles reported the magnitude of regimen change and consisted of 13,668 HIV patients. The estimated national pooled magnitude of regimen change was 37% (95% CI: 34, 44%; Range: 15.1-63.8%) with degree of heterogeneity (I2), 98.7%; p-value < 0.001. Seventeen articles were used to identify the causes for first-line antiretroviral therapy regimen change. The major causes identified were toxicity, 58% (95% CI: 46, 69%; Range: 14.4-88.5%); TB co-morbidity, 12% (95% CI: 8, 16%; Range: 0.8-31.7%); treatment failure, 7% (95% CI: 5, 9%; Range: 0.4-24.4%); and pregnancy, 5% (95% CI: 4, 7%; Range: 0.6-11.9%). Conclusions: The original first-line regimen was changed in one-third of HIV patients on ART in Ethiopia. Toxicity of the drugs, TB co-morbidity, treatment failure, and pregnancy were the main causes for the change of the first-line regimen among HIV patients on antiretroviral therapy

Implications of COVID-19 in high burden countries for HIV/TB: A systematic review of evidence

Background: The triple burden of COVID-19, tuberculosis and human immunodeficiency virus is one of the major global health challenges of the twenty-first century. In high burden HIV/TB countries, the spread of COVID-19 among people living with HIV is a well-founded concern. A thorough understanding of HIV/TB and COVID-19 pandemics is important as the three diseases interact. This may clarify HIV/TB/COVID-19 as a newly related field. However, several gaps remain in the knowledge of the burden of COVID-19 on patients with TB and HIV. This study was conducted to review different studies on SARS-CoV, MERS-CoV or COVID-19 associated with HIV/TB co-infection or only TB, to understand the interactions between HIV, TB and COVID-19 and its implications on the burden of the COVID-19 among HIV/TB co-infected or TB patients, screening algorithm and clinical management. Methods: We conducted an electronic search of potentially eligible studies published in English in the Cochrane Controlled Register of Trials, PubMed, Medrxiv, Google scholar and Clinical Trials Registry databases. We included case studies, case series and observational studies published between January, 2002 and July, 2020 in which SARS-CoV, MERS-CoV and COVID-19 co-infected to HIV/TB or TB in adults. We screened titles, abstracts and full articles for eligibility. Descriptive and meta-analysis were done and results have been presented in graphs and tables. Results: After removing 95 duplicates, 58 out of 437 articles were assessed for eligibility, of which 14 studies were included for descriptive analysis and seven studies were included in the meta-analysis. Compared to the descriptive analysis, the meta-analysis showed strong evidence that current TB exposure was high-risk COVID-19 group (OR 1.67, 95% CI 1.06–2.65, P = 0.03). The pooled of COVID-19/TB severity rate increased from OR 4.50 (95% CI 1.12–18.10, P = 0.03), the recovery rate was high among COVID-19 compared to COVID-19/TB irrespective of HIV status (OR 2.23, 95% CI 1.83–2.74, P \u3c 0.001) and the mortality was reduced among non-TB group (P \u3c 0.001). Conclusion: In summary, TB was a risk factor for COVID-19 both in terms of severity and mortality irrespective of HIV status. Structured diagnostic algorithms and clinical management are suggested to improve COVID-19/HIV/TB or COVID-19/TB co-infections outcomes

Married women’s decision making power on family planning use and associated factors in Mizan-Aman, South Ethiopia: a cross sectional study

BACKGROUND: Women’s use of family planning service is influenced by many factors, especially by their decision making power. A woman’s decision-making power, be it individual or decision made in collaboration with a partner, is the most important factor in the use of family planning in a household. The purpose of this study was to assess the impact of women’s decision making power on family planning use and its associated factors. METHODS: A community-based cross-sectional study was conducted on married women in the child bearing age. The women who were living in Mizan city were selected using the simple random sampling method. Trained nurses collected the data by interview, using a structured and pre-tested questioner. Bivariable and multivariable binary logistic regression analysis was used to identify the associated factors, and the odds ratio with a 95 % CI was computed to assess the strength of the association. Collinearity was also assessed by looking at standard errors in the final fitted model. RESULT: Overall, more than two-thirds [67.2 %: 95 % CI (63–71 %)] of the married women were found to be more autonomous to decide family planning use. Secondary education [AOR: 9.04, 95 % CI: (4.50, 18.16)], government employment [AOR: 4.84, 95 % CI: (2.03, 11.52)], being wives of government employed spouses [AOR 2.71, 95 % CI: (1.24, 7.97)], having husbands with college or university education [AOR: 11.29, 95 % CI: (4.66, 27.35)], and being in the younger age [AOR: 0.27, 95 % CI :(0.09, 0.75)] were significantly associated with women’s decision-making power on family planning. CONCLUSIONS: In this study, women had a high decision making power in family planning use. Age category (34–44-years), formal education, and occupational status had effects on women’s decision making power. Promoting parental adult education and engaging women in out of house employment is essential to improve their decision making power in using family planning

Subnational mapping of HIV incidence and mortality among individuals aged 15–49 years in sub-Saharan Africa, 2000–18 : a modelling study

Background: High-resolution estimates of HIV burden across space and time provide an important tool for tracking and monitoring the progress of prevention and control efforts and assist with improving the precision and efficiency of targeting efforts. We aimed to assess HIV incidence and HIV mortality for all second-level administrative units across sub-Saharan Africa. Methods: In this modelling study, we developed a framework that used the geographically specific HIV prevalence data collected in seroprevalence surveys and antenatal care clinics to train a model that estimates HIV incidence and mortality among individuals aged 15–49 years. We used a model-based geostatistical framework to estimate HIV prevalence at the second administrative level in 44 countries in sub-Saharan Africa for 2000–18 and sought data on the number of individuals on antiretroviral therapy (ART) by second-level administrative unit. We then modified the Estimation and Projection Package (EPP) to use these HIV prevalence and treatment estimates to estimate HIV incidence and mortality by second-level administrative unit. Findings: The estimates suggest substantial variation in HIV incidence and mortality rates both between and within countries in sub-Saharan Africa, with 15 countries having a ten-times or greater difference in estimated HIV incidence between the second-level administrative units with the lowest and highest estimated incidence levels. Across all 44 countries in 2018, HIV incidence ranged from 2 ·8 (95% uncertainty interval 2·1–3·8) in Mauritania to 1585·9 (1369·4–1824·8) cases per 100 000 people in Lesotho and HIV mortality ranged from 0·8 (0·7–0·9) in Mauritania to 676· 5 (513· 6–888·0) deaths per 100 000 people in Lesotho. Variation in both incidence and mortality was substantially greater at the subnational level than at the national level and the highest estimated rates were accordingly higher. Among second-level administrative units, Guijá District, Gaza Province, Mozambique, had the highest estimated HIV incidence (4661·7 [2544·8–8120·3]) cases per 100000 people in 2018 and Inhassunge District, Zambezia Province, Mozambique, had the highest estimated HIV mortality rate (1163·0 [679·0–1866·8]) deaths per 100 000 people. Further, the rate of reduction in HIV incidence and mortality from 2000 to 2018, as well as the ratio of new infections to the number of people living with HIV was highly variable. Although most second-level administrative units had declines in the number of new cases (3316 [81· 1%] of 4087 units) and number of deaths (3325 [81·4%]), nearly all appeared well short of the targeted 75% reduction in new cases and deaths between 2010 and 2020. Interpretation: Our estimates suggest that most second-level administrative units in sub-Saharan Africa are falling short of the targeted 75% reduction in new cases and deaths by 2020, which is further compounded by substantial within-country variability. These estimates will help decision makers and programme implementers expand access to ART and better target health resources to higher burden subnational areas

Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017

A double burden of malnutrition occurs when individuals, household members or communities experience both undernutrition and overweight. Here, we show geospatial estimates of overweight and wasting prevalence among children under 5 years of age in 105 low- and middle-income countries (LMICs) from 2000 to 2017 and aggregate these to policy-relevant administrative units. Wasting decreased overall across LMICs between 2000 and 2017, from 8.4% (62.3 (55.1–70.8) million) to 6.4% (58.3 (47.6–70.7) million), but is predicted to remain above the World Health Organization’s Global Nutrition Target of <5% in over half of LMICs by 2025. Prevalence of overweight increased from 5.2% (30 (22.8–38.5) million) in 2000 to 6.0% (55.5 (44.8–67.9) million) children aged under 5 years in 2017. Areas most affected by double burden of malnutrition were located in Indonesia, Thailand, southeastern China, Botswana, Cameroon and central Nigeria. Our estimates provide a new perspective to researchers, policy makers and public health agencies in their efforts to address this global childhood syndemic

Adolescent transport and unintentional injuries: a systematic analysis using the Global Burden of Disease Study 2019

Background: Globally, transport and unintentional injuries persist as leading preventable causes of mortality and morbidity for adolescents. We sought to report comprehensive trends in injury-related mortality and morbidity for adolescents aged 10–24 years during the past three decades. Methods: Using the Global Burden of Disease, Injuries, and Risk Factors 2019 Study, we analysed mortality and disability-adjusted life-years (DALYs) attributed to transport and unintentional injuries for adolescents in 204 countries. Burden is reported in absolute numbers and age-standardised rates per 100 000 population by sex, age group (10–14, 15–19, and 20–24 years), and sociodemographic index (SDI) with 95% uncertainty intervals (UIs). We report percentage changes in deaths and DALYs between 1990 and 2019. Findings: In 2019, 369 061 deaths (of which 214 337 [58%] were transport related) and 31·1 million DALYs (of which 16·2 million [52%] were transport related) among adolescents aged 10–24 years were caused by transport and unintentional injuries combined. If compared with other causes, transport and unintentional injuries combined accounted for 25% of deaths and 14% of DALYs in 2019, and showed little improvement from 1990 when such injuries accounted for 26% of adolescent deaths and 17% of adolescent DALYs. Throughout adolescence, transport and unintentional injury fatality rates increased by age group. The unintentional injury burden was higher among males than females for all injury types, except for injuries related to fire, heat, and hot substances, or to adverse effects of medical treatment. From 1990 to 2019, global mortality rates declined by 34·4% (from 17·5 to 11·5 per 100 000) for transport injuries, and by 47·7% (from 15·9 to 8·3 per 100 000) for unintentional injuries. However, in low-SDI nations the absolute number of deaths increased (by 80·5% to 42 774 for transport injuries and by 39·4% to 31 961 for unintentional injuries). In the high-SDI quintile in 2010–19, the rate per 100 000 of transport injury DALYs was reduced by 16·7%, from 838 in 2010 to 699 in 2019. This was a substantially slower pace of reduction compared with the 48·5% reduction between 1990 and 2010, from 1626 per 100 000 in 1990 to 838 per 100 000 in 2010. Between 2010 and 2019, the rate of unintentional injury DALYs per 100 000 also remained largely unchanged in high-SDI countries (555 in 2010 vs 554 in 2019; 0·2% reduction). The number and rate of adolescent deaths and DALYs owing to environmental heat and cold exposure increased for the high-SDI quintile during 2010–19. Interpretation: As other causes of mortality are addressed, inadequate progress in reducing transport and unintentional injury mortality as a proportion of adolescent deaths becomes apparent. The relative shift in the burden of injury from high-SDI countries to low and low–middle-SDI countries necessitates focused action, including global donor, government, and industry investment in injury prevention. The persisting burden of DALYs related to transport and unintentional injuries indicates a need to prioritise innovative measures for the primary prevention of adolescent injury. Funding: Bill &amp; Melinda Gates Foundation

Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

Background: In an era of shifting global agendas and expanded emphasis on non-communicable diseases and injuries along with communicable diseases, sound evidence on trends by cause at the national level is essential. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic scientific assessment of published, publicly available, and contributed data on incidence, prevalence, and mortality for a mutually exclusive and collectively exhaustive list of diseases and injuries. Methods: GBD estimates incidence, prevalence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) due to 369 diseases and injuries, for two sexes, and for 204 countries and territories. Input data were extracted from censuses, household surveys, civil registration and vital statistics, disease registries, health service use, air pollution monitors, satellite imaging, disease notifications, and other sources. Cause-specific death rates and cause fractions were calculated using the Cause of Death Ensemble model and spatiotemporal Gaussian process regression. Cause-specific deaths were adjusted to match the total all-cause deaths calculated as part of the GBD population, fertility, and mortality estimates. Deaths were multiplied by standard life expectancy at each age to calculate YLLs. A Bayesian meta-regression modelling tool, DisMod-MR 2.1, was used to ensure consistency between incidence, prevalence, remission, excess mortality, and cause-specific mortality for most causes. Prevalence estimates were multiplied by disability weights for mutually exclusive sequelae of diseases and injuries to calculate YLDs. We considered results in the context of the Socio-demographic Index (SDI), a composite indicator of income per capita, years of schooling, and fertility rate in females younger than 25 years. Uncertainty intervals (UIs) were generated for every metric using the 25th and 975th ordered 1000 draw values of the posterior distribution. Findings: Global health has steadily improved over the past 30 years as measured by age-standardised DALY rates. After taking into account population growth and ageing, the absolute number of DALYs has remained stable. Since 2010, the pace of decline in global age-standardised DALY rates has accelerated in age groups younger than 50 years compared with the 1990–2010 time period, with the greatest annualised rate of decline occurring in the 0–9-year age group. Six infectious diseases were among the top ten causes of DALYs in children younger than 10 years in 2019: lower respiratory infections (ranked second), diarrhoeal diseases (third), malaria (fifth), meningitis (sixth), whooping cough (ninth), and sexually transmitted infections (which, in this age group, is fully accounted for by congenital syphilis; ranked tenth). In adolescents aged 10–24 years, three injury causes were among the top causes of DALYs: road injuries (ranked first), self-harm (third), and interpersonal violence (fifth). Five of the causes that were in the top ten for ages 10–24 years were also in the top ten in the 25–49-year age group: road injuries (ranked first), HIV/AIDS (second), low back pain (fourth), headache disorders (fifth), and depressive disorders (sixth). In 2019, ischaemic heart disease and stroke were the top-ranked causes of DALYs in both the 50–74-year and 75-years-and-older age groups. Since 1990, there has been a marked shift towards a greater proportion of burden due to YLDs from non-communicable diseases and injuries. In 2019, there were 11 countries where non-communicable disease and injury YLDs constituted more than half of all disease burden. Decreases in age-standardised DALY rates have accelerated over the past decade in countries at the lower end of the SDI range, while improvements have started to stagnate or even reverse in countries with higher SDI. Interpretation: As disability becomes an increasingly large component of disease burden and a larger component of health expenditure, greater research and developm nt investment is needed to identify new, more effective intervention strategies. With a rapidly ageing global population, the demands on health services to deal with disabling outcomes, which increase with age, will require policy makers to anticipate these changes. The mix of universal and more geographically specific influences on health reinforces the need for regular reporting on population health in detail and by underlying cause to help decision makers to identify success stories of disease control to emulate, as well as opportunities to improve. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens