2,497 publications from this institution
As cycle time of chips shrinks and die size grows, clock skew measured as a fraction of the cycle time is increasing. Traditional domino circuits shown are especially sensitive because skew must be budgeted in both half-cycles. The problem with such domino pipelines is that evaluation starts when the clock connected to the first gate in the half-cycle rises but the output needs to be valid before the clock on the output latch falls. In the worst case, the evaluate clock is late and the latch clock is early, decreasing time for logic. Many designers realize that some of the overhead can be reduced by using differential domino (also called dual rail) designs. An SR latch or pipeline latch at the end of dual-rail circuits lessens sensitivity to the falling edge. Self-timed techniques eliminate clocks and clock skew, but raise new issues of control overhead, timing assumption verification, and testability. The methodology reported here boosts operating frequency by tolerating clock skew, eliminating latches from the critical path, and better balancing logic between phases of the pipeline.
Our website uses cookies to enhance your experience. By continuing to use our site, or clicking "Continue," you are agreeing to our Cookie Policy | Continue JAMA Internal Medicine HomeNew OnlineCurrent IssueFor Authors Podcast Publications JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry (1919-1959) JN Learning / CMESubscribeJobsInstitutions / LibrariansReprints & Permissions Terms of Use | Privacy Policy | Accessibility Statement 2023 American Medical Association. All Rights Reserved Search All JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Forum Archive JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry Input Search Term Sign In Individual Sign In Sign inCreate an Account Access through your institution Sign In Purchase Options: Buy this article Rent this article Subscribe to the JAMA Internal Medicine journal
Abstract Background SARS-CoV-2 confers high risk of short-term death in residents of long-term care (LTC) facilities, but longer-term risk among survivors is unclear. Methods We extended the follow-up period of a previous, propensity score-matched retrospective cohort study based on the Swedish Senior Alert register. N=3731 LTC residents with documented SARS-CoV-2 until 15 September 2020 were matched to 3731 uninfected controls using time-dependent propensity scores on age, sex, health status, comorbidities, and prescription medications. In a sensitivity analysis, matching included also geographical region and Senior Alert registration time. The outcome was all-cause mortality over 8 months (until October 24, 2020). The absolute risk of death was examined using Kaplan-Meier plots. Hazard ratios (HR) for death over time were estimated using flexible parametric models with restricted cubic splines. Cox regression was used to estimate HRs and 95% confidence intervals (CIs) in 30-day intervals of follow-up until 210 days. Results The median age was 87 years and 65% were women. Excess mortality was highest 5 days after documented infection (HR 19.1, 95% CI, 14.6-24.8), after which excess mortality decreased. From the second month onwards, mortality rate became lower in infected residents than controls. The HR for death during days 61-210 of follow-up was 0.41 in the main analysis (95% CI, 0.34-0.50) and 0.76 (95% CI, 0.62-0.93) in the sensitivity analysis. Median survival of uninfected controls was 1.6 years, which was much lower than the national life expectancy in Sweden at age 87 (5.05 years in men, 6.07 years in women). Conclusions No excess mortality was observed in LTC residents who survived the acute SARS-CoV-2 infection. Life expectancy of uninfected residents was much lower than that of the general population of the same age and sex. This suggests that LTC resident status should be accounted for in years-of-life-lost estimates for COVID-19 burden of disease calculations. Impact statement We certify that this work is novel. This research adds to the literature by showing there was no excess mortality observed in long-term care facility residents who survived the acute SARS-CoV-2 infection, and that life expectancy of uninfected residents was much lower than that of the general population of same age and sex. This has major repercussions for estimation of years of life lost in infected long term care facility residents. Key points SARS-CoV-2 infection sharply increased mortality risk among residents of long-term care (LTC) facilities in the first month. After the first month, the mortality risk in infected residents rapidly returned to baseline and dropped below the mortality risk of uninfected controls, where it remained lower for 8 months of follow-up. Median survival of uninfected controls was 1.6 years, which was much lower than national life expectancy in Sweden at age 87. Why does this matter? Whereas LTC residents who recover from SARS-CoV-2 infection may be concerned about having residual debilitation caused by the infection, we found no excess mortality was in those who survived the acute infection. Because life expectancy of uninfected residents was much lower than that of the general population of same age and sex, LTC resident status should be accounted for in estimations of years of life lost.
ABSTRACT Background China witnessed a surge of Omicron infections after abandoning zero COVID strategies on December 7, 2022. The authorities report very sparse deaths based on very restricted criteria, but massive deaths are speculated. Methods We aimed to estimate the COVID-19 fatalities in Mainland China until summer 2023 using the experiences of Hong Kong and of South Korea in 2022 as prototypes. Both these locations experienced massive Omicron waves after having had very few SARS-CoV-2 infections during 2020-2021. We estimated age-stratified infection fatality rates (IFRs) in Hong Kong and South Korea during 2022 and extrapolated to the population age structure of Mainland China. We also accounted separately for deaths of residents in long-term care facilities in both Hong Kong and South Korea. Results IFR estimates in non-elderly strata were modestly higher in Hong Kong than South Korea and projected 987,455 and 619,549 maximal COVID-19 deaths, respectively, if the entire China population was infected. Expected COVID-19 deaths in Mainland China until summer 2023 ranged from 49,962 to 691,219 assuming 25-70% of the non-elderly population being infected and variable protection of elderly (from none to three-quarter reduction in fatalities). The main analysis (45% of non-elderly population infected and fatality impact among elderly reduced by half) estimated 152,886-249,094 COVID-19 deaths until summer 2023. Large uncertainties exist regarding potential changes in dominant variant, health system strain, and impact on non-COVID-19 deaths. Conclusions The most critical factor that can affect total COVID-19 fatalities in China is the extent to which the elderly can be protected.
Abstract Importance The Global Burden of Disease (GBD) study provides widely used estimates of mortality and disability-adjusted life years (DALYs) attributable to risk factors. Objective To evaluate the variability and consistency of GBD risk factor estimates for mortality and DALYs. Data Sources GBD Risk Factor collaboration estimates extracted from published tables and IHME repository. Study Selection GBD Risk Factor collaboration publications (2010-2023). Data Extraction and Synthesis Death and DALY estimates were manually extracted by one reviewer with independent validation of a random sample of 100 by another with no discrepancies. Risk factor naming was harmonized across iterations to ensure comparability; those with inconsistent definitions were excluded. Main Outcomes and Measures We calculated the fluctuations in deaths and DALYs for each risk factor across GBD iterations for different years (2010-2023), and between the original and subsequently revised estimates for each year (1990-2021) expressed in the ratio of the min-max range to the mean (R/M) and coefficient of variation (CV). We examined in more detail analyses diet and low physical activity. Finally, point estimates were compared to the previous iterations’ estimates 95% uncertainty intervals (95%UI) for GBD 2019, 2021 and 2023. Results Across GBD iterations from 2010 to 2023, the median R/M was 0.8 (range, 0–3.8) for deaths, and 0.7 (range, 0.1–3.3) for DALYs. Among level 2 dietary and child and maternal malnutrition death estimates showed high variability (R/M>1 for 7/16 and 3/8 of risks, respectively). When comparing original estimates with GBD 2019, 2021, and 2023 estimates for the same years, the median R/M was 0.5 (0.0-2.9) for deaths and 0.4 (0-2.9) for DALYs. The CV was above 0.2 for 320/580 (52%) of death and 306/609 of DALY estimates. 70-96% of point estimates for red meat, sugar-sweetened beverages, fruits, vegetables and seafood omega-3 fatty acids in GBD 2021 fell outside the GBD 2019 95%UI. In GBD 2023, only diet high in trans fats had over half of point estimates outside the GBD 2021 95%UI. Conclusions and Relevance GBD estimates show large instability, particularly for behavioral risks, making them unlikely to simply reflect genuine changes over time, and warranting caution in interpretation. Key Points Question How stable and consistent are the Global Burden of Disease (GBD) estimates for mortality and disability-adjusted life years (DALYs) attributable to major risk factors across iterations from 2010 to 2023? Findings In this study comparing estimates across eight GBD iterations, substantial variability was observed. Behavioral, particularly dietary risks showed the greatest instability. Comparing revised estimates across iterations half the estimates had a coefficient of variation exceeding 0.2. A third of estimates for dietary risks in GBD 2021 fell outside the corresponding GBD 2019 uncertainty intervals. Meaning GBD risk factor estimates, especially for behavioral and dietary risks, show marked inconsistency likely reflecting methodological or data changes rather than true burden shifts.
Zambia has one of the most liberal abortion laws in sub-Saharan Africa.However, rates of unsafe abortion remain high with negative health and economic consequences.Little is known about the economic burden on women of abortion care-seeking in low income countries.The majority of studies focus on direct costs (e.g.: hospital fees).This paper estimates the individual-level economic burden of safe and unsafe abortion care-seeking in Zambia, incorporating all indirect and direct costs.It uses data collected in 2013 from a tertiary hospital in Lusaka, (n=112) with women who had an abortion.Three treatment routes are identified: i) safe abortion at the hospital ii) unsafe clandestine medical abortion initiated elsewhere with post-abortion care at the hospital and iii) unsafe abortion initiated elsewhere with post-abortion care at the hospital.Based on these three typologies, we use descriptive analysis and linear regression to estimate the costs for women of seeking safe and unsafe abortion and to establish whether the burden of abortion care-seeking costs is equally distributed across the sample.Around 39% of women had an unsafe abortion, incurring substantial economic costs before seeking post-abortion care.Adolescents and poorer women are more likely to use unsafe abortion.Unsafe abortion requiring post-abortion care costs women 27% more than a safe abortion.When accounting for uncertainty this figure increases dramatically.For safe and unsafe abortions, unofficial provider payments represent a major cost to women.This study demonstrates that despite a liberal legislation, Zambia still needs better dissemination of the law to women and providers and resources to ensure abortion service access.The policy implications of this study include: the role of pharmacists and mid-level providers in the provision of medical abortion services; increased access to contraception, especially for adolescents; and, elimination of demands for unofficial provider payments.
Abstract Genome searches for identifying susceptibility loci for the same complex disease often give inconclusive or inconsistent results. Genome Search Meta‐analysis (GSMA) is an established non‐parametric method to identify genetic regions that rank high on average in terms of linkage statistics (e.g., lod scores) across studies. Meta‐analysis typically aims not only to obtain average estimates, but also to quantify heterogeneity. However, heterogeneity testing between studies included in GSMA has not been developed yet. Heterogeneity may be produced by differences in study designs, study populations, and chance, and the extent of heterogeneity might influence the conclusions of a meta‐analysis. Here, we propose and explore metrics that indicate the extent of heterogeneity for specific loci in GSMA based on Monte Carlo permutation tests. We have also developed software that performs both the GSMA and the heterogeneity testing. To illustrate the concept, the proposed methodology was applied to published data from meta‐analyses of rheumatoid arthritis (4 scans) and schizophrenia (20 scans). In the first meta‐analysis, we identified 11 bins with statistically low heterogeneity and 8 with statistically high heterogeneity. The respective numbers were 9 and 6 for the schizophrenia meta‐analysis. For rheumatoid arthritis, bins 6.2 (the HLA region that is a well‐documented susceptibility locus for the disease) and 16.3 (16q12.2‐q23.1) had both high average ranks and low between‐study heterogeneity. For schizophrenia, this was seen for bin 3.2 (3p25.3‐p22.1) and heterogeneity was still significantly low after adjusting for its high average rank. Concordance was high between the proposed metrics and between weighted and unweighted analyses. Data from genome searches should be synthesized and interpreted considering both average ranks and heterogeneity between studies. Genet. Epidemiol . 28:123–137, 2005. © 2004 Wiley‐Liss, Inc.
