32 research outputs found

    Inflation and late time acceleration in braneworld cosmological models with varying brane tension

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    Braneworld models with variable brane tension λ\lambda introduce a new degree of freedom that allows for evolving gravitational and cosmological constants, the latter being a natural candidate for dark energy. We consider a thermodynamic interpretation of the varying brane tension models, by showing that the field equations with variable λ\lambda can be interpreted as describing matter creation in a cosmological framework. The particle creation rate is determined by the variation rate of the brane tension, as well as by the brane-bulk energy-matter transfer rate. We investigate the effect of a variable brane tension on the cosmological evolution of the Universe, in the framework of a particular model in which the brane tension is an exponentially dependent function of the scale factor. The resulting cosmology shows the presence of an initial inflationary expansion, followed by a decelerating phase, and by a smooth transition towards a late accelerated de Sitter type expansion. The varying brane tension is also responsible for the generation of the matter in the Universe (reheating period). The physical constraints on the model parameters, resulted from the observational cosmological data, are also investigated.Comment: 25 pages, 8 figures, accepted for publication in European Physical Journal

    A survey on some risk factors and evaluation of their impacts on streptococcosis incidence in rainbow trout farms in Fars province

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    Streptococcosis is an infectious bacterial disease that causes huge economic losses in cold water aquaculture industry. Disease outbreak was experienced in some of provinces farms in recent years. Fars Province, has produced 7,000 tons of cold-water fish. According to Streptococcosis report in 1381 from the province and Proceedings have been performed during 10 years against disease and also economic losses impact of disease on rainbow trout production, risk assessment of Streptococcosis conducted on the plan. In this study, of 586 sick fish (have symptoms) studied 230 fish (39.24%) Streptococcus and (26.62%) gram negative bacteria were isolated. Of 754 healthy grower fish and fry (with no clinical signs) 10 fish or fry (1.32%)infected with streptococcus and 60 fish or fry(7.95%) infected with gram negative bacteria (Yersinia ruckeri, Pseudomonas, entrobacteriaceae). According to biochemical tests and molecular examinations, isolated Streptococcuus iniae and Streptococcus sp. Furthermore some physical and chemical parameters measured and aerobic bacteria of selected farm water counted. These factors effects on disease incidence and changes were evaluated by applying logistic regression

    Breast cancer risk factors in Iran: A systematic review & Meta-analysis

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    Objectives: Breast cancer is known as one of the deadliest forms of cancer, and it is increasing globally. There are a variety of proven and controversial risk factors for this malignancy. Herein, we aimed to undertake a systematic review and meta-analysis focus on the epidemiology of breast cancer risk factors in Iran. Methods: We performed a systematic search via PubMed, Scopus, Web of Science, and Persian databases for identifying studies published on breast cancer risk factors up to March 2019. Meta-analyses were done for risk factors reported in more than one study. We calculated odds ratios (ORs) with corresponding 95 confidence intervals (CIs) using a fixed/random-effects models. Results: Thirty-nine studies entered into the meta-analysis. Pooling of ORs showed a significant harmful effect for risk factors including family history (OR: 1.80, 95CI 1.47-2.12), hormonal replacement therapy (HRT) (OR: 5.48, 95CI 0.84-1.74), passive smokers (OR: 1.68, 95CI 1.34-2.03), full-term pregnancy at age 30 (OR: 3.41, 95CI 1.19-5.63), abortion (OR: 1.84, 95CI 1.35-2.33), sweets consumption (OR: 1.71, 95CI 1.32-2.11) and genotype Arg/Arg (crude OR: 1.59, 95CI 1.07-2.10), whereas a significant protective effect for late menarche (OR: 0.58, 95CI 0.32-0.83), nulliparity (OR: 0.68, 95CI 0.39-0.96), 13-24 months of breastfeeding (OR: 0.68, 95CI 0.46-0.90), daily exercise (OR: 0.59, 95CI 0.44-0.73) and vegetable consumption (crude OR: 0.28, 95CI 0.10-0.46). Conclusions: This study suggests that factors such as family history, HRT, passive smokers, late full-term pregnancy, abortion, sweets consumption and genotype Arg/Arg might increase risk of breast cancer development, whereas late menarche, nulliparity, 13-24 months breastfeeding, daily exercise and vegetable consumption had an inverse association with breast cancer development. © 2020 Amir Shamshirian et al., published by De Gruyter

    Burden of disease scenarios for 204 countries and territories, 2022–2050: a forecasting analysis for the Global Burden of Disease Study 2021

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    Background Future trends in disease burden and drivers of health are of great interest to policy makers and the public at large. This information can be used for policy and long-term health investment, planning, and prioritisation. We have expanded and improved upon previous forecasts produced as part of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) and provide a reference forecast (the most likely future), and alternative scenarios assessing disease burden trajectories if selected sets of risk factors were eliminated from current levels by 2050. Methods Using forecasts of major drivers of health such as the Socio-demographic Index (SDI; a composite measure of lag-distributed income per capita, mean years of education, and total fertility under 25 years of age) and the full set of risk factor exposures captured by GBD, we provide cause-specific forecasts of mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) by age and sex from 2022 to 2050 for 204 countries and territories, 21 GBD regions, seven super-regions, and the world. All analyses were done at the cause-specific level so that only risk factors deemed causal by the GBD comparative risk assessment influenced future trajectories of mortality for each disease. Cause-specific mortality was modelled using mixed-effects models with SDI and time as the main covariates, and the combined impact of causal risk factors as an offset in the model. At the all-cause mortality level, we captured unexplained variation by modelling residuals with an autoregressive integrated moving average model with drift attenuation. These all-cause forecasts constrained the cause-specific forecasts at successively deeper levels of the GBD cause hierarchy using cascading mortality models, thus ensuring a robust estimate of cause-specific mortality. For non-fatal measures (eg, low back pain), incidence and prevalence were forecasted from mixed-effects models with SDI as the main covariate, and YLDs were computed from the resulting prevalence forecasts and average disability weights from GBD. Alternative future scenarios were constructed by replacing appropriate reference trajectories for risk factors with hypothetical trajectories of gradual elimination of risk factor exposure from current levels to 2050. The scenarios were constructed from various sets of risk factors: environmental risks (Safer Environment scenario), risks associated with communicable, maternal, neonatal, and nutritional diseases (CMNNs; Improved Childhood Nutrition and Vaccination scenario), risks associated with major non-communicable diseases (NCDs; Improved Behavioural and Metabolic Risks scenario), and the combined effects of these three scenarios. Using the Shared Socioeconomic Pathways climate scenarios SSP2-4.5 as reference and SSP1-1.9 as an optimistic alternative in the Safer Environment scenario, we accounted for climate change impact on health by using the most recent Intergovernmental Panel on Climate Change temperature forecasts and published trajectories of ambient air pollution for the same two scenarios. Life expectancy and healthy life expectancy were computed using standard methods. The forecasting framework includes computing the age-sex-specific future population for each location and separately for each scenario. 95% uncertainty intervals (UIs) for each individual future estimate were derived from the 2·5th and 97·5th percentiles of distributions generated from propagating 500 draws through the multistage computational pipeline. Findings In the reference scenario forecast, global and super-regional life expectancy increased from 2022 to 2050, but improvement was at a slower pace than in the three decades preceding the COVID-19 pandemic (beginning in 2020). Gains in future life expectancy were forecasted to be greatest in super-regions with comparatively low life expectancies (such as sub-Saharan Africa) compared with super-regions with higher life expectancies (such as the high-income super-region), leading to a trend towards convergence in life expectancy across locations between now and 2050. At the super-region level, forecasted healthy life expectancy patterns were similar to those of life expectancies. Forecasts for the reference scenario found that health will improve in the coming decades, with all-cause age-standardised DALY rates decreasing in every GBD super-region. The total DALY burden measured in counts, however, will increase in every super-region, largely a function of population ageing and growth. We also forecasted that both DALY counts and age-standardised DALY rates will continue to shift from CMNNs to NCDs, with the most pronounced shifts occurring in sub-Saharan Africa (60·1% [95% UI 56·8–63·1] of DALYs were from CMNNs in 2022 compared with 35·8% [31·0–45·0] in 2050) and south Asia (31·7% [29·2–34·1] to 15·5% [13·7–17·5]). This shift is reflected in the leading global causes of DALYs, with the top four causes in 2050 being ischaemic heart disease, stroke, diabetes, and chronic obstructive pulmonary disease, compared with 2022, with ischaemic heart disease, neonatal disorders, stroke, and lower respiratory infections at the top. The global proportion of DALYs due to YLDs likewise increased from 33·8% (27·4–40·3) to 41·1% (33·9–48·1) from 2022 to 2050, demonstrating an important shift in overall disease burden towards morbidity and away from premature death. The largest shift of this kind was forecasted for sub-Saharan Africa, from 20·1% (15·6–25·3) of DALYs due to YLDs in 2022 to 35·6% (26·5–43·0) in 2050. In the assessment of alternative future scenarios, the combined effects of the scenarios (Safer Environment, Improved Childhood Nutrition and Vaccination, and Improved Behavioural and Metabolic Risks scenarios) demonstrated an important decrease in the global burden of DALYs in 2050 of 15·4% (13·5–17·5) compared with the reference scenario, with decreases across super-regions ranging from 10·4% (9·7–11·3) in the high-income super-region to 23·9% (20·7–27·3) in north Africa and the Middle East. The Safer Environment scenario had its largest decrease in sub-Saharan Africa (5·2% [3·5–6·8]), the Improved Behavioural and Metabolic Risks scenario in north Africa and the Middle East (23·2% [20·2–26·5]), and the Improved Nutrition and Vaccination scenario in sub-Saharan Africa (2·0% [–0·6 to 3·6]). Interpretation Globally, life expectancy and age-standardised disease burden were forecasted to improve between 2022 and 2050, with the majority of the burden continuing to shift from CMNNs to NCDs. That said, continued progress on reducing the CMNN disease burden will be dependent on maintaining investment in and policy emphasis on CMNN disease prevention and treatment. Mostly due to growth and ageing of populations, the number of deaths and DALYs due to all causes combined will generally increase. By constructing alternative future scenarios wherein certain risk exposures are eliminated by 2050, we have shown that opportunities exist to substantially improve health outcomes in the future through concerted efforts to prevent exposure to well established risk factors and to expand access to key health interventions. Funding Bill & Melinda Gates Foundation

    Experimental modeling of Electric kinetic barrier (EKB) in Porous Medium, Explain its numerical solution methods and analysis of the relations in the Hydraulic-Electric‌ coupled flow

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    This research project is aimed at developing the theoretical knowledge of hydraulic-electric coupled flows and its results can be used to zero the flow in a porous medium such as seepage in engineering barriers made with clay and And also the definition of a new concept called electrokinetic engineering barrier. Also, the simulation of the electrokinetic barrier process was carried out using the finite difference method, and the methods of solving the numerical model of this process were investigated. Finally, the Forward Difference Approximation method was proposed due to more accuracy for coding in the MATLAB software. Laboratory studies was provided by an innovative physical model. To achieve this, several experiments were performed on kaolinite soil with a specific gravity of 1.3 gr/cm3, 1.315 gr/cm3, and 1.33 gr/cm3 under different electric potentials and the results of the experiments. They were compared with each other. The results showed that  ability of the electrical gradient to generate electro-osmotic flow to overcome the hydraulic flow and create an electrokinetic barrier is affected by the input voltage as well as the dry specific gravity of the samples in the cell and with increasing them, this ability increases so that in the denser sample the electrical gradients applied to the cell were able to stop the hydraulic flow in the higher hydraulic heads while in the less compacted samples the hydraulic heads were stopped at lower values

    Investigating the effects of using Nettle (Urtica dioica ), Menta pulagum (Oreganum valgare) and Zizaphora (Thymyus valgaris) medicinal plants on performance, carcass quality, blood biochemical parameters and blood cells of broilers

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    This experiment was conducted to evaluate the effects of using Nettle,Menta pulagum and ‌‌Zizaphora medicinal plants on performance, carcass quality, blood biochemical parameters and blood cells of broilers. The experiment was conducted in a completely randomized design with 288 broilers (Ross-308) in 8 treatments and 3 replicates (with 12 birds in each replicate) from 1 to 42 days and included: 1) control group without using any medicinal plants, 2) 1.5% of ‌‌Nettle, 3) 1.5% of Menta pulagum, 4) 1.5% of Zizaphora, 5) 1.5% of Nettle and Menta pulagum, 6) 1.5% of  Nettle and Zizaphora, 7) 1.5% of Menta pulagum and ‌‌Zizaphora, 8) 1.5% of Nettle,Menta pulagum and ‌‌Zizaphora. The results showed that using these medicinal plants and their mixtures had significant effects on performance, carcass traits and blood biochemical parameters of broilers (
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