374 research outputs found
Pilot-scale studies of combined clarification, filtration, and ultraviolet radiation systems for disinfection of secondary municipal wastewater effluent
Disinfection of municipal wastewater effluent was evaluated using three alternatives, including: (1) low-pressure (LP)+medium-pressure (MP) UV lamps; (2) clarifier+LP+MP; and (3) pressurized sand filter+ LP+MP. Total coliform (TC), fecal coliform (FC), fecal Streptococcus (FS), TSS, several physicochemical parameters, absorbtivity and UV transmittance (UVT; ) were tested. The UVT for secondary, clarified and filtered effluents were 3.5, 34 and 50, respectively. A 15 photo-reactivation in secondary effluent disinfected by LP lamp was observed, while it was limited to 0.03 by the MP lamp after filtration. Filtration to a surface overflow rate (SOR) of 1050 L/m2h, followed by MP irradiation at a dose of 230 mW s/cm2 was an effective alternative to reduce the TC, FC, and FS in the disinfected secondary effluent. Filtration+MP lamp met the standards of 1000 TC and 400 FC/100 mL for effluent discharge to receiving waters. This process can also inactivate FS, effecting a 6-log reduction. Among the evaluated alternatives, none of the other treatment systems performed as well as the pressurized sand filter+MP lamp, making this the best combination for post-treatment and disinfection of secondary effluent from a well-run wastewater treatment plant. © 2010 Elsevier B.V. All rights reserved
Assessment of combating-desertification strategies using the linear assignment method
Nowadays desertification, as a global problem, affects many countries in the
world, especially developing countries like Iran. With respect to increasing
importance of desertification and its complexity, the necessity of attention
to the optimal combating-desertification alternatives is essential.
Selecting appropriate strategies according to all effective criteria to
combat the desertification process can be useful in rehabilitating
degraded lands and avoiding degradation in vulnerable fields. This study
provides systematic and optimal strategies of combating desertification by
use of a
group decision-making model. To this end, the preferences of indexes were
obtained through using the Delphi model, within the framework of multi-attribute
decision making (MADM). Then, priorities of strategies were evaluated by
using linear assignment (LA) method. According to the results, the
strategies to prevent improper change of land use (A18), development and
reclamation of plant cover (A23), and control overcharging of groundwater
resources (A31) were identified as the most important
strategies for combating desertification in this study area. Therefore, it
is suggested that the aforementioned ranking results be considered in
projects which control and reduce the effects of desertification and
rehabilitate degraded lands
FUSION OF NON-THERMAL AND THERMAL SATELLITE IMAGES BY BOOSTED SVM CLASSIFIERS FOR CLOUD DETECTION
The goal of ensemble learning methods like Bagging and Boosting is to improve the classification results of some weak classifiers gradually. Usually, Boosting algorithms show better results than Bagging. In this article, we have examined the possibility of fusion of non-thermal and thermal bands of Landsat 8 satellite images for cloud detection by using the boosting method. We used SVM as a base learner and the performance of two kinds of Boosting methods including AdaBoost.M1 and σ Boost was compared on remote sensing images of Landsat 8 satellite. We first extracted the co-occurrence matrix features of non-thermal and thermal bands separately and then used PCA method for feature selection. In the next step AdaBoost.M1 and σ Boost algorithms were applied on non-thermal and thermal bands and finally, the classifiers were fused using majority voting. Also, we showed that by changing the regularization parameter (C) the result of σ Boost algorithm can significantly change and achieve overall accuracy and cloud producer accuracy of 74%, and 0.53 kappa coefficient that shows better results in comparison to AdaBoost.M1
Evaluating the scale, growth, and origins of right-wing echo chambers on YouTube
Although it is understudied relative to other social media platforms, YouTube
is arguably the largest and most engaging online media consumption platform in
the world. Recently, YouTube's outsize influence has sparked concerns that its
recommendation algorithm systematically directs users to radical right-wing
content. Here we investigate these concerns with large scale longitudinal data
of individuals' browsing behavior spanning January 2016 through December 2019.
Consistent with previous work, we find that political news content accounts for
a relatively small fraction (11%) of consumption on YouTube, and is dominated
by mainstream and largely centrist sources. However, we also find evidence for
a small but growing "echo chamber" of far-right content consumption. Users in
this community show higher engagement and greater "stickiness" than users who
consume any other category of content. Moreover, YouTube accounts for an
increasing fraction of these users' overall online news consumption. Finally,
while the size, intensity, and growth of this echo chamber present real
concerns, we find no evidence that they are caused by YouTube recommendations.
Rather, consumption of radical content on YouTube appears to reflect broader
patterns of news consumption across the web. Our results emphasize the
importance of measuring consumption directly rather than inferring it from
recommendations.Comment: 29 pages, 21 figures, 15 table
Risk factors and control strategies for silicotuberculosis as an occupational disease
Silicotuberculosis is critical in community settings among workers and employees exposed to silica dust. Older age of entry (>30 years), male sex, infection with human immunodeficiency virus (HIV), exposure duration, smoking, chronic obstructive pulmonary disease, migration, the severity of the silicosis and the intensity of the exposure are potential risk factors. Lack of timely diagnosis and treatment for tuberculosis (TB) may also raise the rate of infection; previous treatment of TB is possibly associated with the development of silicotuberculosis in more than half of patients, increasing with age (>40 years). Identification of risk factors benefits not only the academic research community, but also the workers or employees and policy making. Some strategies can be implemented, such as controlling or reducing exposure to silica dust, ensuring continuity of treatment of TB or extended anti-TB treatment, management of the situation by occupational health professionals, prevention of oscillating migration, providing workers with compensation, training and education in occupational health, improving the quality of life of miners and workers, intensive medical surveillance and TB screening in routine health check ups, and policy making for higher immunity to inhibit inhalation of dust by workers or employees
A liquid metal-based process for tuning the thermoelectric properties of bismuth indium systems
To obtain the optimum performance of thermoelectric materials, engineering their characteristics, such as crystal structures and phases, is critical. Liquid metal-based processes are great methods for controlling and tuning such properties. In this study, indium (In), of different concentrations, is introduced into bismuth (Bi) via a liquid metal-based process to tailor the crystallization arrangements and investigate the thermoelectric properties of the Bi-In systems. These systems were prepared by a liquid metal-based melting and solidification process. Thermoelectric properties, including the Seebeck coefficient, thermal conductivity, and resistivity, were analyzed using in-house built apparatus units. The sample with 2% indium concentration showed the highest Seebeck coefficient and electrical resistivity. Thermal conductivity was observed to decrease with increasing indium concentration up to 5%, followed by a reverse trend above this concentration. Dominated by the thermal conductivity effect, the sample with 5% indium concentration showed the highest average value for the figure of merit (zT) for the Bi-In systems. The zT value of this sample was nearly twice than that of the pristine bismuth. According to our analyses, this increase could be attributed to the crystal modalities of the formed BiIn crystals with optimum crystallite dimensions and distributions, along with the emergence of specific diffraction peaks, in the pool of bismuth. This study provides a facile and low-cost liquid metal-based pathway for designing thermoelectric materials by tuning their crystal structures and orientations using liquid metal-enabled processes
Burden of ischemic heart diseases in Iran, 1990-2010: Findings from the global burden of disease study 2010
Background: Cardiovascular diseases are viewed worldwide as one of the main causes of death.This study aims to report the burden of ischemic heart diseases (IHDs) in Iran by using data of the global burden of disease (GBD) study, 1990-2010. Materials and Methods: The GBD study 2010 was a systematic effort to provide comprehensive data to calculate disability-adjusted life years (DALYs) for diseases and injuries in the world. Years of life lost (YLLs) due to premature mortality were computed on the basis of cause-of-death estimates, using Cause of Death Ensemble model (CODEm). Years lived with disability (YLDs) were assessed by the multiplication of prevalence, the disability weight for a sequel, and the duration of symptoms. A systematic review of published and unpublished data was performed to evaluate the distribution of diseases, and consequently prevalence estimates were calculated with a Bayesian meta-regression method (DisMod-MR). Data from population-based surveys were used for producing disability weights. Uncertainty from all inputs into the calculations of DALYs was disseminated by Monte Carlo simulation techniques. Results: The age-standardized IHDs DALY specified rate decreased 31.25 over 20 years from 1990 to 2010 from 4720 (95% uncertainty interval (UI): 4,341-5,099) to 3,245 (95% UI: 2,810-3,529) person-years per 100,000. The decrease were 38.14% among women and 26.87% among men. The age-standardized IHDs death specefied rate decreased by 21.17% from 222) 95% UI: 207-243 (to 175 (95% UI:152-190) person-years per 100,000 in both the sexes. The age-standardized YLL and YLD rates decreased 32.05% and 4.28%, respectively, in the above period. Conclusion: Despite decreasing age-standardized IHD of mortality, YLL, YLD, and DALY rates from 1990 to 2010, population growth and aging increased the global burden of IHD. YLL has decreased more than IHD deaths and YLD since 1990 but IHD mortality remains the greatest contributor to disease burden. © 2015 Journal of Research in Medical Sciences
Worldwide trends in diabetes since 1980: a pooled analysis of 751 population-based studies with 4.4 million participants
BACKGROUND: One of the global targets for non-communicable diseases is to halt, by 2025, the rise in the age-standardised adult prevalence of diabetes at its 2010 levels. We aimed to estimate worldwide trends in diabetes, how likely it is for countries to achieve the global target, and how changes in prevalence, together with population growth and ageing, are affecting the number of adults with diabetes. METHODS: We pooled data from population-based studies that had collected data on diabetes through measurement of its biomarkers. We used a Bayesian hierarchical model to estimate trends in diabetes prevalence—defined as fasting plasma glucose of 7·0 mmol/L or higher, or history of diagnosis with diabetes, or use of insulin or oral hypoglycaemic drugs—in 200 countries and territories in 21 regions, by sex and from 1980 to 2014. We also calculated the posterior probability of meeting the global diabetes target if post-2000 trends continue. FINDINGS: We used data from 751 studies including 4 372 000 adults from 146 of the 200 countries we make estimates for. Global age-standardised diabetes prevalence increased from 4·3% (95% credible interval 2·4–7·0) in 1980 to 9·0% (7·2–11·1) in 2014 in men, and from 5·0% (2·9–7·9) to 7·9% (6·4–9·7) in women. The number of adults with diabetes in the world increased from 108 million in 1980 to 422 million in 2014 (28·5% due to the rise in prevalence, 39·7% due to population growth and ageing, and 31·8% due to interaction of these two factors). Age-standardised adult diabetes prevalence in 2014 was lowest in northwestern Europe, and highest in Polynesia and Micronesia, at nearly 25%, followed by Melanesia and the Middle East and north Africa. Between 1980 and 2014 there was little change in age-standardised diabetes prevalence in adult women in continental western Europe, although crude prevalence rose because of ageing of the population. By contrast, age-standardised adult prevalence rose by 15 percentage points in men and women in Polynesia and Micronesia. In 2014, American Samoa had the highest national prevalence of diabetes (>30% in both sexes), with age-standardised adult prevalence also higher than 25% in some other islands in Polynesia and Micronesia. If post-2000 trends continue, the probability of meeting the global target of halting the rise in the prevalence of diabetes by 2025 at the 2010 level worldwide is lower than 1% for men and is 1% for women. Only nine countries for men and 29 countries for women, mostly in western Europe, have a 50% or higher probability of meeting the global target. INTERPRETATION: Since 1980, age-standardised diabetes prevalence in adults has increased, or at best remained unchanged, in every country. Together with population growth and ageing, this rise has led to a near quadrupling of the number of adults with diabetes worldwide. The burden of diabetes, both in terms of prevalence and number of adults affected, has increased faster in low-income and middle-income countries than in high-income countries. FUNDING: Wellcome Trust
Anti-inflammatory effects of different statins in rheumatoid arthritis; a randomized double-blind controlled clinical trial
Introduction: Statin family drugs are lipid-lowering agents with anti-inflammatory effects. Objectives: The aim of our study was to evaluate anti-inflammatory effects of different statins in rheumatoid arthritis patients. Patients and Methods: Around 161 eligible subjects with rheumatoid arthritis were enrolled. They randomly were divided into three groups. The first group received 40 mg/daily atorvastatin, the second group received 40 mg/daily simvastatin, and the third group received placebo as control for six months. To calculate the disease activity, DAS-28 (Disease Activity Score 28) was used while VAS (visual analog scale) was used to assess the severity of pain in rheumatoid arthritis patients. DAS-28, erythrocyte sedimentation rates (ESR) and lipid profiles were assessed once for the baseline and then after three and six months of intervention. Data was analyzed by SPSS by a P value <0.05 which was set to be significant. Results: DAS-28 score in months 0, 3 and 6 in atorvastatin, simvastatin and placebo groups was (5.36 +/- 1.02, 3.23 +/- 1.24 and 2.81 +/- 1.13), (5.29 +/- 0.87, 2.75 +/- 1.16 and 2.57 +/- 1.00) and (5.52 +/- 0.96, 3.90 +/- 1.10 and 3.87 +/- 1.52), respectively. Mean of DAS-28 score differences between placebo and atorvastatin groups was 0.6 +/- 0.16 (P < 0.01); the score differences between simvastatin and placebo was 0.900 +/- 0.16 that was significant (P < 0.01), however, the score differences was not significant between atorvastatin and simvastatin groups (P = 0.261). Conclusion: Statins decrease inflammation in rheumatoid arthritis patients
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