134 research outputs found
The linear barycentric rational method for a class of delay Volterra integro-differential equations
A method for solving delay Volterra integro-differential equations is introduced. It is based on two applications of linear barycentric rational interpolation, barycentric rational quadrature and barycentric rational finite differences. Its zero–stability and convergence are studied. Numerical tests demonstrate the excellent agreement of our implementation with the predicted convergence orders
Creep failure of hierarchical materials
Creep failure of hierarchical materials is investigated by simulation of beam
network models. Such models are idealizations of hierarchical fibrous materials
where bundles of load-carrying fibers are held together by multi-level
(hierarchical) cross-links. Failure of individual beams is assumed to be
governed by stress-assisted thermal activation over local barriers, and beam
stresses are computed by solving the global balance equations of linear and
angular momentum across the network. Disorder is mimicked by a statistical
distribution of barrier heights. Both initially intact samples and samples
containing side notches of various length are considered. Samples with
hierarchical cross-link patterns are simulated alongside reference samples
where cross-links are placed randomly without hierarchical organization. The
results demonstrate that hierarchical patterning may strongly increase creep
strain and creep lifetime while reducing the lifetime variation. This is due to
the fact that hierarchical patterning induces a failure mode that differs
significantly from the standard scenario of failure by nucleation and growth of
a critical crack. Characterization of this failure mode demonstrates good
agreement between the present simulations and experimental findings on
hierarchically patterned paper sheets.Comment: 10 pages, 5 figure
An evaluation of hospital admission respiratory disease attributed to sulfur dioxide ambient concentration in Ahvaz from 2011 through 2013
There is no doubt that air pollutants have adverse
impacts on human health. The main objective of this study
was to evaluate hospital admission respiratory disease
(HARD) attributed to sulfur dioxide levels in Ahvaz during
three successive years. Data was taken from Iranian
Environmental Protection Agency (EPA). The AirQ2,2,3
model is used to quantify the impact of SO2 on inhabitants
of Ahvaz and in terms of hospital admission respiratory diseases.
This is a kind of statistical model which is based on
some epidemiological indices such as relative risk, baseline
incidence, and attributable proportion. Sampling was already
performed for 24 h in four stations during 2011–2013. Four
stations are good representative for residential, high traffic,
industry, and background sites which cover the whole area
of the Ahvaz city. Regarding to gravimetric scale, raw data
of sulfur dioxide was processed using Excel software.
Encoding, filtering, and processing were conducted to prepare
input file for the Air Q2,2,3 model. After running model,1 Air Pollution and Respiratory Diseases Research Center, Ahvaz
Jundishapur University of Medical Sciences, Ahvaz, Iran
2 Environmental Technologies Research Center, Ahvaz Jundishapur
University of Medical Sciences, Ahvaz, Iran
3 Islamic Azad University, Tehran Medical Sciences Branch,
Tehran, Iran
4 Razi Teaching Hospital, Clinical Research Development Center,
Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
5 Department of Internal Medicine, Division of Pulmonology, Imam
Khomeini Hospital, Ahvaz Jundishapur University of Medical
Sciences, Ahvaz, Iran
6 Nutrition&Metabolic Diseases Research Center, Ahvaz Jundishapur
University of Medical Sciences, Ahvaz, Iran
7 Social Determinants of Health Research Center, Yasuj University of
Medical Sciences, Yasuj, Iran
8 Research Center for Environmental Pollutants, Qom University of
Medical Sciences, Qom, Iran
9 Department of Environmental Health Engineering, Faculty of Health,
Bushehr University of Medical Sciences, Bushehr, Iran
10 The Persian Gulf Marine Biotechnology Research Center, The
Persian Gulf Research Center, Bushehr University of Medical
Sciences, Bushehr, Iran
11 Hyperlipidemia Research Center, Department of Laboratory
Sciences School of Paramedical Sciences, Ahvaz Jundishapur
University of Medical Sciences, Ahvaz, IR, Iran
12 Environmental Research Institute, Academic Center for Education,
Culture and Research (ACECR), Rasht, Iran
13 Department of Anaesthesiology, Faculty of Medicine, Ahvaz
Jundishapur University of Medical Sciences, Ahvaz, Iran
14 Occupational Hazards Control Research Center and Department of
Environmental Health Engineering, School of Public Health
Environmental, Shahid Beheshti University of Medical Sciences,
Tehran, Iran
15 Faculty of Food Science & Technology, Tehran University,
Tehran, Iran
16 Student Research Committee, Department of Environmental Health
Engineering, Ahvaz Jundishapur University of Medical Sciences,
Ahvaz, Iran
Environ Sci Pollut Res
DOI 10.1007/s11356-016-7447-xoutputs presented in term of hospital admissions respiratory
cases. Based on our result, the highest mean and maximum of
seasonal and annual levels for sulfur dioxide were observed in
2013. We concluded that obnoxious quality of fuel and some
deficiencies in maintenance and operation of industries lead to
worse quality of ambient air especially in 2013. Cumulative
cases of HARD attributed to sulfur dioxide level at central of
relative risk (RR) were estimated 24, 25, and 30 persons for
2011, 2012, and 2013, respectively. The finding of this study
showed that total mean of sulfur dioxide was higher than
standard concentration. We also noticed that wintertime concentrations
of sulfur dioxide during three successive years
were higher than of those levels in summer
Global, regional, and national burden of chronic kidney disease, 1990–2017 : a systematic analysis for the Global Burden of Disease Study 2017
Background
Health system planning requires careful assessment of chronic kidney disease (CKD) epidemiology, but data for morbidity and mortality of this disease are scarce or non-existent in many countries. We estimated the global, regional, and national burden of CKD, as well as the burden of cardiovascular disease and gout attributable to impaired kidney function, for the Global Burden of Diseases, Injuries, and Risk Factors Study 2017. We use the term CKD to refer to the morbidity and mortality that can be directly attributed to all stages of CKD, and we use the term impaired kidney function to refer to the additional risk of CKD from cardiovascular disease and gout.
Methods
The main data sources we used were published literature, vital registration systems, end-stage kidney disease registries, and household surveys. Estimates of CKD burden were produced using a Cause of Death Ensemble model and a Bayesian meta-regression analytical tool, and included incidence, prevalence, years lived with disability, mortality, years of life lost, and disability-adjusted life-years (DALYs). A comparative risk assessment approach was used to estimate the proportion of cardiovascular diseases and gout burden attributable to impaired kidney function.
Findings
Globally, in 2017, 1·2 million (95% uncertainty interval [UI] 1·2 to 1·3) people died from CKD. The global all-age mortality rate from CKD increased 41·5% (95% UI 35·2 to 46·5) between 1990 and 2017, although there was no significant change in the age-standardised mortality rate (2·8%, −1·5 to 6·3). In 2017, 697·5 million (95% UI 649·2 to 752·0) cases of all-stage CKD were recorded, for a global prevalence of 9·1% (8·5 to 9·8). The global all-age prevalence of CKD increased 29·3% (95% UI 26·4 to 32·6) since 1990, whereas the age-standardised prevalence remained stable (1·2%, −1·1 to 3·5). CKD resulted in 35·8 million (95% UI 33·7 to 38·0) DALYs in 2017, with diabetic nephropathy accounting for almost a third of DALYs. Most of the burden of CKD was concentrated in the three lowest quintiles of Socio-demographic Index (SDI). In several regions, particularly Oceania, sub-Saharan Africa, and Latin America, the burden of CKD was much higher than expected for the level of development, whereas the disease burden in western, eastern, and central sub-Saharan Africa, east Asia, south Asia, central and eastern Europe, Australasia, and western Europe was lower than expected. 1·4 million (95% UI 1·2 to 1·6) cardiovascular disease-related deaths and 25·3 million (22·2 to 28·9) cardiovascular disease DALYs were attributable to impaired kidney function.
Interpretation
Kidney disease has a major effect on global health, both as a direct cause of global morbidity and mortality and as an important risk factor for cardiovascular disease. CKD is largely preventable and treatable and deserves greater attention in global health policy decision making, particularly in locations with low and middle SDI
Prevalence and Correlates of Psychiatric Disorders in a National Survey of Iranian Children and Adolescents
Objective: Considering the impact of rapid sociocultural, political, and economical changes on societies and families, population-based surveys of mental disorders in different communities are needed to describe the magnitude of mental health problems and their disabling effects at the individual, familial, and societal levels.
Method: A population-based cross sectional survey (IRCAP project) of 30 532 children and adolescents between 6 and 18 years was conducted in all provinces of Iran using a multistage cluster sampling method. Data were collected by 250 clinical psychologists trained to use the validated Persian version of the semi-structured diagnostic interview Kiddie-Schedule for Affective Disorders and Schizophrenia-PL (K-SADS-PL).
Results: In this national epidemiological survey, 6209 out of 30 532 (22.31%) were diagnosed with at least one psychiatric disorder. The anxiety disorders (14.13%) and behavioral disorders (8.3%) had the highest prevalence, while eating disorders (0.13%) and psychotic symptoms (0.26%) had the lowest. The prevalence of psychiatric disorders was significantly lower in girls (OR = 0.85; 95% CI: 0.80-0.90), in those living in the rural area (OR = 0.80; 95% CI: 0.73-0.87), in those aged 15-18 years (OR = 0.92; 95% CI: 0.86-0.99), as well as that was significantly higher in those who had a parent suffering from mental disorders (OR = 1.96; 95% CI: 1.63-2.36 for mother and OR = 1.33; 95% CI: 1.07-1.66 for father) or physical illness (OR = 1.26; 95% CI: 1.17-1.35 for mother and OR = 1.19; 95% CI: 1.10-1.28 for father).
Conclusion: About one fifth of Iranian children and adolescents suffer from at least one psychiatric disorder. Therefore, we should give a greater priority to promoting mental health and public health, provide more accessible services and trainings, and reduce barriers to accessing existing services
Global, regional, and national burden of osteoarthritis, 1990–2020 and projections to 2050: a systematic analysis for the Global Burden of Disease Study 2021
Background
Osteoarthritis is the most common form of arthritis in adults, characterised by chronic pain and loss of mobility. Osteoarthritis most frequently occurs after age 40 years and prevalence increases steeply with age. WHO has designated 2021–30 the decade of healthy ageing, which highlights the need to address diseases such as osteoarthritis, which strongly affect functional ability and quality of life. Osteoarthritis can coexist with, and negatively effect, other chronic conditions. Here we estimate the burden of hand, hip, knee, and other sites of osteoarthritis across geographies, age, sex, and time, with forecasts of prevalence to 2050.
Methods
In this systematic analysis for the Global Burden of Disease Study, osteoarthritis prevalence in 204 countries and territories from 1990 to 2020 was estimated using data from population-based surveys from 26 countries for knee osteoarthritis, 23 countries for hip osteoarthritis, 42 countries for hand osteoarthritis, and US insurance claims for all of the osteoarthritis sites, including the other types of osteoarthritis category. The reference case definition was symptomatic, radiographically confirmed osteoarthritis. Studies using alternative definitions from the reference case definition (for example self-reported osteoarthritis) were adjusted to reference using regression models. Osteoarthritis severity distribution was obtained from a pooled meta-analysis of sources using the Western Ontario and McMaster Universities Arthritis Index. Final prevalence estimates were multiplied by disability weights to calculate years lived with disability (YLDs). Prevalence was forecast to 2050 using a mixed-effects model.
Findings
Globally, 595 million (95% uncertainty interval 535–656) people had osteoarthritis in 2020, equal to 7·6% (95% UI 6·8–8·4) of the global population, and an increase of 132·2% (130·3–134·1) in total cases since 1990. Compared with 2020, cases of osteoarthritis are projected to increase 74·9% (59·4–89·9) for knee, 48·6% (35·9–67·1) for hand, 78·6% (57·7–105·3) for hip, and 95·1% (68·1–135·0) for other types of osteoarthritis by 2050. The global age-standardised rate of YLDs for total osteoarthritis was 255·0 YLDs (119·7–557·2) per 100 000 in 2020, a 9·5% (8·6–10·1) increase from 1990 (233·0 YLDs per 100 000, 109·3–510·8). For adults aged 70 years and older, osteoarthritis was the seventh ranked cause of YLDs. Age-standardised prevalence in 2020 was more than 5·5% in all world regions, ranging from 5677·4 (5029·8–6318·1) per 100 000 in southeast Asia to 8632·7 (7852·0–9469·1) per 100 000 in high-income Asia Pacific. Knee was the most common site for osteoarthritis. High BMI contributed to 20·4% (95% UI –1·7 to 36·6) of osteoarthritis. Potentially modifiable risk factors for osteoarthritis such as recreational injury prevention and occupational hazards have not yet been explored in GBD modelling.
Interpretation
Age-standardised YLDs attributable to osteoarthritis are continuing to rise and will lead to substantial increases in case numbers because of population growth and ageing, and because there is no effective cure for osteoarthritis. The demand on health systems for care of patients with osteoarthritis, including joint replacements, which are highly effective for late stage osteoarthritis in hips and knees, will rise in all regions, but might be out of reach and lead to further health inequity for individuals and countries unable to afford them. Much more can and should be done to prevent people getting to that late stage
Global, regional, and national burden of colorectal cancer and its risk factors, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019
Funding: F Carvalho and E Fernandes acknowledge support from Fundação para a Ciência e a Tecnologia, I.P. (FCT), in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy i4HB; FCT/MCTES through the project UIDB/50006/2020. J Conde acknowledges the European Research Council Starting Grant (ERC-StG-2019-848325). V M Costa acknowledges the grant SFRH/BHD/110001/2015, received by Portuguese national funds through Fundação para a Ciência e Tecnologia (FCT), IP, under the Norma Transitória DL57/2016/CP1334/CT0006.proofepub_ahead_of_prin
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