Arm current reversal-based modular multilevel DC-DC converter

Nowadays, most of the converters used in high-power high-voltage (HV) applications are the conventional modular multilevel converters (MMC). However, in the case of DC-DC conversion, an imbalance of the capacitor voltages occurs and the conventional MMC fails to operate correctly. This paper introduces an arm current reversal-based modular multilevel DC-DC converter, which successfully provides balance among the capacitor voltages while operating in DC-DC conversion. The proposed configuration is used in medium voltage DC grids to feed DC loads or to interconnect between two DC grids of different voltage levels. The proposed converter is a two-stage DC-DC modular converter, which consists of a single-phase half-bridge MMC with half-bridge submodules (HBMMC) followed by a single-phase H-bridge MMC with half-bridge submodules (SMs). The operational concept of the proposed converter is based on reversing the arm current direction and reversing the output terminals with the help of the H-bridge MMC stage, which ensures the same direction of the voltage at the load terminals. The proposed converter provides a high conversion ratio, bidirectional power flow, simple architecture, and a simple control scheme. Detailed illustrations, analysis, and design of the proposed converter are presented. Besides, MATLAB-based and Opal RT-based simulation results and experimental results are presented to validate the proposed configuration claims

WHO European Childhood Obesity Surveillance Initiative: body mass index and level of overweight among 6-9-year-old children from school year 2007/2008 to school year 2009/2010.

BACKGROUND: The World Health Organization (WHO) Regional Office for Europe has established the Childhood Obesity Surveillance Initiative (COSI) to monitor changes in overweight in primary-school children. The aims of this paper are to present the anthropometric results of COSI Round 2 (2009/2010) and to explore changes in body mass index (BMI) and overweight among children within and across nine countries from school years 2007/2008 to 2009/2010. METHODS: Using cross-sectional nationally representative samples of 6-9-year-olds, BMI, anthropometric Z-scores and overweight prevalence were derived from measured weight and height. Significant changes between rounds were assessed using variance and t-tests analyses. RESULTS: At Round 2, the prevalence of overweight (including obesity; WHO definitions) ranged from 18% to 57% among boys and from 18% to 50% among girls; 6 - 31% of boys and 5 - 21% of girls were obese. Southern European countries had the highest overweight prevalence. Between rounds, the absolute change in mean BMI (range: from -0.4 to +0.3) and BMI-for-age Z-scores (range: from -0.21 to +0.14) varied statistically significantly across countries. The highest significant decrease in BMI-for-age Z-scores was found in countries with higher absolute BMI values and the highest significant increase in countries with lower BMI values. The highest significant decrease in overweight prevalence was observed in Italy, Portugal and Slovenia and the highest significant increase in Latvia and Norway. CONCLUSIONS: Changes in BMI and prevalence of overweight over a two-year period varied significantly among European countries. It may be that countries with higher prevalence of overweight in COSI Round 1 have implemented interventions to try to remedy this situation

Alcohol use among amateur sportsmen in Ireland

<p>Abstract</p> <p>Background</p> <p>The objective of this study was to establish baseline data on alcohol consumption patterns, behaviours and harms among amateur sportsmen in the Republic of Ireland.</p> <p>Findings</p> <p>The study presents findings from the baseline survey for a cluster randomised controlled trial to evaluate the effectiveness of a community intervention programme to reduce problem alcohol use among a representative sample of Gaelic Athletic Association (GAA) clubs in two counties in the Republic of Ireland. Self reported alcohol use, prevalence of binge drinking, AUDIT scores and alcohol-related harms were assessed in amateur GAA sportsmen aged 16 years and over.</p> <p>Nine hundred and sixty (960) players completed questionnaires (72% response rate). Mean age was 24.0 years (S.D. 5.2). Of those aged 18 years or over, 75% had post-primary education; most (864, 90%) were current drinkers and 8.2% were regular smokers. The self-reported average yearly alcohol consumption was 12.5 litres. Almost one third (31%) of current drinkers reported drinking over the recommended limit of 21 standard drinks per week and just over half (54.3%) reported drinking 6 or more standard drinks in a row at least once a week (regular binge drinking). Of those who (self) completed the Alcohol Use Disorder Identification Test (AUDIT) questionnaire, three-quarters (74.7%) had a score of 8 or more; 11.5% had a score of 20 or above warranting referral for diagnostic evaluation and treatment. Almost all (87.6%) of the 864 drinkers reported experiencing at least one harm due to their drinking. These alcohol misuse outcomes were higher than those found in a nationally representative sample of males of a similar age. There were strong associations between regular binge drinking and reporting harms such as being in a fight (adjusted odds ratio (OR) 2.02, p < 0.001), missing time from work or college (adjusted OR 1.39, p = 0.04) or being in an accident (adjusted OR 1.78, p = 0.04).</p> <p>Conclusions</p> <p>These male amateur sportsmen reported high rates of alcohol consumption and alcohol-related harm.</p

Smoking cessation in disadvantaged estates in the North East.

Letter to the editor. Sir, Smoking is a risk factor for heart disease, stroke and cancer and contributes to an estimated 21% of deaths.1-3 The SLAN survey (2007) showed overall smoking rates at 29%.4 However, smoking prevalence remains high in areas of deprivation and smoking has been identified as the principal reason for the inequalities in death rates between rich and poor.5 The aim of this project was to establish the prevalence of smoking in areas of high deprivation in the former NEHB health board. A further aim was to offer and introduce a community based and community led smoking cessation programme to smokers and to determine whether this community programme reduced the rates of smoking among this population. This study design was a community based and community led prospective comparative controlled before and after trial. Six areas were chosen to receive the intervention and three areas were chosen as control areas. The control areas matched the intervention areas in terms of deprivation and demographics. Furthermore, in order to ascertain that this service was being offered to those who do not usually attend the existing smoking cessation services, a review of client attendance on existing smoking cessation services was also carried out..

Past and Future Changes of Land Use/Land Cover and the Potential Impact on Ecosystem Services Value of Damietta Governorate, Egypt

This investigation aims to assess the changes of Land Use/Land Cover (LULC) and its impact on ecosystem services value in Damietta Governorate, Egypt. To fulfill this aim, Landsat data of TM5 in 2001, ETM in 2011 and OLI in 2021 were used. The Maximum Likelihood Classifier was employed to track the changes in LULC of the study area. Cellular automata (CA) and Markov model adopted from IDRISI software were used for accurate prediction of the LULC in 2031. The VALIDATE model in TerrSet was used to compare the predicted 2031 LULC with actual 2021 LULC to assess the accuracy of the model. The Millennium Ecosystem Assessment was utilized to assess the value per unit area of land types. The results indicated that there was a noticeable change in different land cover classes during the duration 2001–2021. Results showed that there are decreases in the cultivated area and the bare area, meanwhile the urban area was increased. The cultivated area was remarkably decreased recording 548.2 km2 (62.15%) at 2001, 548.2 km2 (55.79%) at 2011 and 468.96 km2 (53.16%) at 2021 of the total study area. However, the percentage of urban area increased; reporting 65.69 km2 (7.45%), 124.57 km2 (14.12%), and 176.67 km2 (20.03%) at 2001, 2011, and 2021, respectively. LULC analyses in 2031 showed an increase in the urban area by 2.8% and a decrease in the cultivated area by 7.2%. The kappa index values are greater than 0.80, which shows a strong agreement between simulated and predicted LULC maps. The comprehensive index of Damietta Governorate ranges from 100 to 400. The ES that experienced positive ESV changes during the study period gives strength indicator for achieving the sustainable development of Damietta Governorate. To prevent further ecosystem degradation and to ensure the best possible delivery of ES, it is necessary to reduce the current drivers of LULC changes within the buildup in agricultural land. The study helps the local authorities to better understand the land use system and to develop an improved land use management strategies that manage the urban expansion and guarantee the ecological conservation

School sociodemographic characteristics and obesity in schoolchildren: does the obesity definition matter?

Background: Existing evidence on the role of sociodemographic variables as risk factors for overweight and obesity in school-aged children is inconsistent. Furthermore, findings seem to be influenced by the obesity definition applied. Therefore, this study aimed to investigate if school sociodemographic indicators were associated with weight status in Irish primary schoolchildren and whether this association was sensitive to different obesity classification systems. Methods: A nationally representative cross-sectional sample of 7,542 Irish children (53.9% girls), mean age 10.4 (±1.2SD) years, participating in the Childhood Obesity Surveillance Initiative in the 2010, 2012/2013 or 2015/2016 waves were included. Height, weight and waist circumference were objectively measured. Five definitions of obesity were employed using different approaches for either body mass index (BMI) or abdominal obesity. Associations between overweight and obesity and sociodemographic variables were investigated using adjusted multilevel logistic regression analyses. Results: Children attending disadvantaged schools were more likely to be overweight and obese than their peers attending non-disadvantaged schools, regardless of the obesity classification system used. Associations remained significant for the BMI-based obesity definitions when the sample was stratified by sex and age group, except for boys aged 8-10.5 years. Only boys aged ≥10.5 years in disadvantaged schools had higher odds of abdominal obesity (UK 1990 waist circumference growth charts: OR=1.56, 95%CI=1.09-2.24; waist-to-height ratio: OR=1.78, 95%CI=1.14-2.79) than those in non-disadvantaged schools. No associations were observed for school urbanisation level. Conclusions: School socioeconomic status was a strong determinant of overweight and obesity in Irish schoolchildren, and these associations were age- and sex-dependent. School location was not associated with overweight or obesity. There remains a need to intervene with school-aged children in disadvantaged schools, specifically among those approaching adolescence, to prevent a trajectory of obesity into adult life.Health Service Executiv

Additional file 2: of School sociodemographic characteristics and obesity in schoolchildren: does the obesity definition matter?

Prevalence of overweight and obesity according to different definitions among Irish children COSI study. Percentages, 95% confidence intervals and Chi-squared p-values are provided to show the prevalence of overweight and obesity in school-aged children by age and sex, school socioeconomic level and school urbanisation level using three body mass index-based definitions and two abdominal obesity definitions. (DOCX 18 kb

Additional file 1: of School sociodemographic characteristics and obesity in schoolchildren: does the obesity definition matter?

Overweight and obesity definitions. Detailed information is provided on the IOTF, CDC 2000 and WHO 2007 cut-offs used in this study to define overweight and obesity school-aged children. (DOCX 17 kb