38 research outputs found
Bounds on graviton mass using weak lensing and SZ effect in galaxy clusters
In General Relativity (GR), the graviton is massless. However, a common
feature in several theoretical alternatives of GR is a non-zero mass for the
graviton. These theories can be described as massive gravity theories. Despite
many theoretical complexities in these theories, on phenomenological grounds,
the implications of massive gravity have been widely used to put bounds on
graviton mass. One of the generic implications of giving a mass to the graviton
is that the gravitational potential will follow a Yukawa-like fall off. We use
this feature of massive gravity theories to probe the mass of graviton by using
the largest gravitationally bound objects, namely galaxy clusters. In this
work, we use the mass estimates of galaxy clusters measured at various
cosmologically defined radial distances measured via weak lensing (WL) and
Sunyaev-Zel'dovich (SZ) effect. We also use the model independent values of
Hubble parameter smoothed by a non-parametric method, Gaussian process.
Within confidence region, we obtain the mass of graviton eV with the corresponding Compton length scale Mpc from weak lensing and eV with Mpc from SZ effect. This analysis improves the upper bound on graviton
mass obtained earlier from galaxy clusters.Comment: 9 Pages, 3 Figures, 2 Tables, Accepted for publication in Physics
Letters
Examining Temporal Variation of the Fermi Coupling Constant using SNe Ia Light Curves
In standard model, the Fermi coupling constant, , sets the strength of
electroweak decay. We attempt an approach to constrain the temporal variation
of the Fermi coupling constant . To probe it, Type Ia supernovae (SNe Ia)
light curves are being used as a source of reliable primordial nucleosynthesis
events across the redshifts. We utilized studies suggesting that in the initial
phase after the SNe Ia explosion, the electroweak decay of is the key contributor to powering the SNe Ia
light curve. We hence used the Pan-STARRS supernovae catalog having 1169
supernovae light curves in , , , and spectral filters. The
post-peak decrease in the apparent magnitude of light curves (in the rest frame
of SNe) was related to the electroweak decay rate of primordial
nucleosynthesis. Further, the decay rate relates to . To keep the analysis
independent of the cosmological model, we used the Hubble parameter measurement
and a non-parametric statistical method, the Gaussian Process. Our study
suggests a small yet finite temporal variation of and puts a strong upper
bound on the present value of the fractional change in the Fermi coupling
constant i.e;
using datasets spread over a redshift range .Comment: 14 pages, 7 figures, 1 tabl
Strong lensing systems and galaxy cluster observations as probe to the cosmic distance duality relation
In this paper, we use large scale structure observations to test the cosmic
distance duality relation (CDDR), , with
and , being the luminosity and angular diameter
distances, respectively. In order to perform the test, the following data set
are considered: strong lensing systems and galaxy cluster measurements (gas
mass fractions). No specific cosmological model is adopted, only a flat
universe is assumed. By considering two parametrizations, we obtained
the validity of the CDDR within which is in full agreement with
other recent tests involving cosmological data. It is worth to comment that our
results are independent of the baryon budget of galaxy clusters.Comment: 6 pages, two figs, one tabl
Evaluation of coronary arteries in congenital heart disease in children : diagnostic comparison of electrocardiogram-gated and non-electrocardiogram-gated computed tomography cardiac angiograpy
Purpose: To compare the visualization and anatomy of coronary arteries in children (≤ 2 years) with congenital heart disease (CHD) on non-electrocardiogram (ECG)-gated and ECG-gated computed tomography angiography (CTA). Material and methods: In this retrospective study, approved by the Ethics Committee of our institute, evaluation of coronary arteries in CHD was performed in 40 children on non-ECG-gated CTA and in 42 children on ECG-gated CTA. The origin and course of the right coronary artery (RCA), left main coronary artery (LMCA), left anterior descending (LAD) artery, and left circumflex (LCX) artery were evaluated by 2 paediatric radiologists independently. Results: ECG-gated CT scans yielded increased (additional) visualization of all the coronary arteries, when compared to non-ECG-gated CT scans. The RCA, LMCA, LAD artery, and LCX artery were visualized in 47.5%, 62.5%, 55%, and 32.5% of children, respectively, on non-ECG-gated studies, while they were visualized in 64.3%, 92.8%, 80.9%,
and 62% children, respectively, on ECG-gated studies. The coronary artery anatomical variations were also supplementarily detected more in the ECG-gated group (23.8%) than in the non-ECG gated group (2.5%).
Conclusions: ECG-gated CT cardiac angiography studies yield enhanced diagnostic outcomes for the evaluation of the coronary arteries in comparison to non-ECG-gated studies
The global burden of cancer attributable to risk factors, 2010-19 : a systematic analysis for the Global Burden of Disease Study 2019
Background Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. Methods The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk-outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. Findings Globally, in 2019, the risk factors included in this analysis accounted for 4.45 million (95% uncertainty interval 4.01-4.94) deaths and 105 million (95.0-116) DALYs for both sexes combined, representing 44.4% (41.3-48.4) of all cancer deaths and 42.0% (39.1-45.6) of all DALYs. There were 2.88 million (2.60-3.18) risk-attributable cancer deaths in males (50.6% [47.8-54.1] of all male cancer deaths) and 1.58 million (1.36-1.84) risk-attributable cancer deaths in females (36.3% [32.5-41.3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20.4% (12.6-28.4) and DALYs by 16.8% (8.8-25.0), with the greatest percentage increase in metabolic risks (34.7% [27.9-42.8] and 33.3% [25.8-42.0]). Interpretation The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.Peer reviewe
Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries
Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely
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Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation