Groundwater Infiltration and Rainfall-Derived Inflow and Infiltration Assessment in Separate Sewer Systems (Case Study: Tehran Urban Area)

Separate sewer networks are designed and built to collect foul sewage from buildings and convey it to wastewater treatment plants (WWTPs). However, due to some holes and cracks on the pipes or unsealed pipe joints, a volume of ground or subsurface water that is placed in saturated or unsaturated zones intrudes sewers and WWTPs. In a condition that the wastewater level in the sewer stands higher than the groundwater level, wastewater leaks into the soil and groundwater and this phenomenon is called sewer exfiltration. Moreover, during a rain event, a part of the precipitation gets into the sewer system through the illicit connection of the yard drains and roof downspouts to the building’s lateral, and this part of the flow is called rainfall-derived inflow and infiltration (RDII). In this research, infiltration, exfiltration, and RDII were evaluated in a 16-month period to show the range of inflow and infiltration in the sewer network under the service of the South Tehran WWTP. Results show that the infiltration constitutes the major volume of the total inflow and infiltration. But the RDII leads to more operational problems due to its nature as an intense flow. After calculating the range of inflow and infiltration, results show that the average infiltration rate that entered the WWTP in the year 2014 was 0.0175 L/s/ha that is much less than the values mentioned in Criterion No. 118. Furthermore, total inflow and infiltration in five hours of the study period crossed the upper limit of the inflow and infiltration range (0.6 L/s/ha) in Criterion No. 118 that shows the high percentage of illicit connections in Tehran and a high volume of rainfall that enters the sewer network. Accordingly, the inflow and infiltration range in the Criterion No. 118 seems to be an unsound range and it needs some revisions

Analyzing and studying educational pyramid and changes in demographical indices of Tehran students during the school years 2000-2010

One of the effective factors in planning is paying attention to the increase and decrease of student population. In this study, using a variety of resources, it has been attempted that the growth changes and population decrease in the student population of Tehran in a 10-year period and considering the measures such as population density in-class students, the educational staff ratio, academic pyramid, the separation of school, number of classes and other aspects will be dealt with. Obviously, the results and findings of this potential research could be used in educational planning and population policy. In the present study, the method of data collection was done using the quantitative techniques of demography and a variety of statistical calculations. The research findings showed that the student population, number of classes and schools and the staff of ministry of education are being significantly decreased and has been associated with a negative growth rate in all levels

Analyzing and studying educational pyramid and changes in demographical indices of Tehran students during the school years 2000-2010

One of the effective factors in planning is paying attention to the increase and decrease of student population. In this study, using a variety of resources, it has been attempted that the growth changes and population decrease in the student population of Tehran in a 10-year period and considering the measures such as population density in-class students, the educational staff ratio, academic pyramid, the separation of school, number of classes and other aspects will be dealt with. Obviously, the results and findings of this potential research could be used in educational planning and population policy. In the present study, the method of data collection was done using the quantitative techniques of demography and a variety of statistical calculations. The research findings showed that the student population, number of classes and schools and the staff of ministry of education are being significantly decreased and has been associated with a negative growth rate in all levels

Comparing the performance and problems of pre-school centers and kindergartens in Varamin city in Iran

The necessity to examine the performance and problems of pre-school course is due to the significant effect of this course in the child's growth. In this descriptive study, we used systematic perspective to survey and the statistical community is all the managers, coaches and parents of pre-school centers of Varamin in academic year of 2012-13 (2772 people). The sample size is 598 people, according to Morgan table collecting information has been done through observation, interviews, questionnaires and in library and validity of tool research was approved by the teachers and the coefficient of 941/0 = α was calculated, which is an indicative of appropriate stability. To analyze the data, descriptive and inferential statistics were used. The results indicated that there is a significant difference in performance and problems in preschool centers under the protection of education and welfare centers in the size of input, process and environment

Comparing the performance and problems of pre-school centers and kindergartens in Varamin city in Iran

The necessity to examine the performance and problems of pre-school course is due to the significant effect of this course in the child's growth. In this descriptive study, we used systematic perspective to survey and the statistical community is all the managers, coaches and parents of pre-school centers of Varamin in academic year of 2012-13 (2772 people). The sample size is 598 people, according to Morgan table collecting information has been done through observation, interviews, questionnaires and in library and validity of tool research was approved by the teachers and the coefficient of 941/0 = α was calculated, which is an indicative of appropriate stability. To analyze the data, descriptive and inferential statistics were used. The results indicated that there is a significant difference in performance and problems in preschool centers under the protection of education and welfare centers in the size of input, process and environment

Standardization of a trauma symptoms checklist for children

Background: The aim of this study was to standardize and assign validity and reliability of the Trauma Symptom Checklist for Children (TSCC-A). Methods: Normative data for the TSCC-A were based on 3042 students participating in a prevalence child abuse study in 19 different locations of Tehran and 140 participants who had been refered to the run-away children centers in Tehran. After the TSCC was validated on run-away and abused children, it was made available to researchers doing larger studies on a normative group. Results: Reliability analysis of the TSCC-A scales in the normative sample demonstrated high internal consistency. The evidence for its validations (convergent, discriminant and construct validity) showed that they were significantly acceptable. Conclusion: This paper presents data demonstrating the psychometric reliability and validity of the TSCC-A scales in the Iranian student population. We suggest to include the TSCC-A in a battery of relevant standardized tests

Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

Background: Estimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period. Methods: 22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution. Findings: Global all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations. Interpretation: Global adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic