COVID-19 attack ratio among children critically depends on the time to removal and activity levels

The attack ratio in a subpopulation is defined as the total number of infections over the total number of individuals in this subpopulation. Using a methodology based on modified age-stratified transmission dynamics model, we estimated the attack ratio of COVID-19 among children (individuals 0-11 years) in Ontario, Canada when a large proportion of individuals eligible for vaccination (age 12 and above) are vaccinated to achieve herd immunity among this subpopulation, or the effective herd immunity with additional physical distancing measures (hence effective herd immunity). We describe the relationship between this attack ratio among children, the time to remove infected individuals from the transmission chain and the children-to-children daily contact rate, while considering the increased transmissibility of virus variants (using the Delta variant as an example). We further illustrate the generality and applicability of the methodology established by performing an analysis of the attack ratio of COVID-19 among children in the Canadian population. The clinical attack ratio, the number of symptomatic infections over the total population can be informed from the attack ratio, and both can be reduced substantially via a combination of higher vaccine coverage in the vaccine eligible population, reduced social mixing among children, and rapid testing and isolation.

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COVID-19 Vaccine Intention among Healthcare Workers in Saudi Arabia: A Cross-Sectional Survey

Vaccines ◽

10.3390/vaccines9080835 ◽

2021 ◽

Vol 9 (8) ◽

pp. 835

Author(s):

Mohammed Noushad ◽

Mohammad Zakaria Nassani ◽

Anas B. Alsalhani ◽

Pradeep Koppolu ◽

Fayez Hussain Niazi ◽

...

Keyword(s):

Saudi Arabia ◽

Healthcare System ◽

Healthcare Workers ◽

Vaccine Coverage ◽

Vaccination Campaign ◽

Herd Immunity ◽

Positive Sign ◽

Cross Sectional Survey ◽

Cross Sectional ◽

Public Health Strategies

The COVID-19 pandemic has caused largescale morbidity and mortality and a tremendous burden on the healthcare system. Healthcare workers (HCWs) require adequate protection to avoid onward transmission and minimize burden on the healthcare system. Moreover, HCWs can also influence the general public into accepting the COVID-19 vaccine. Therefore, determining COVID-19 vaccine intention among HCWs is of paramount importance to plan tailor-made public health strategies to maximize vaccine coverage. A structured questionnaire was administered in February and March 2021 among HCWs in Saudi Arabia using convenience sampling, proceeding the launch of the vaccination campaign. HCWs from all administrative regions of Saudi Arabia were included in the study. In total, 674 out of 1124 HCWs responded and completed the survey (response rate 59.9%). About 65 percent of the HCWs intended to get vaccinated. The intention to vaccinate was significantly higher among HCWs 50 years of age or older, Saudi nationals and those who followed the updates about COVID-19 vaccines (p < 0.05). The high percentage (26 percent) of those who were undecided in getting vaccinated is a positive sign. As the vaccination campaign gathers pace, the attitude is expected to change over time. Emphasis should be on planning healthcare strategies to convince the undecided HCWs into accepting the vaccine in order to achieve the coverage required to achieve herd immunity.

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A microbial treatment population dynamics optimization approach

Journal of Intelligent & Fuzzy Systems ◽

10.3233/jifs-210127 ◽

2021 ◽

pp. 1-15

Author(s):

Jinding Gao

Keyword(s):

Population Dynamics ◽

Information Exchange ◽

Information Diffusion ◽

Optimization Problems ◽

Microbial Control ◽

Function Optimization ◽

Optimization Approach ◽

Dynamics Model ◽

Population Dynamics Model ◽

Number Of Individuals

In order to solve some function optimization problems, Population Dynamics Optimization Algorithm under Microbial Control in Contaminated Environment (PDO-MCCE) is proposed by adopting a population dynamics model with microbial treatment in a polluted environment. In this algorithm, individuals are automatically divided into normal populations and mutant populations. The number of individuals in each category is automatically calculated and adjusted according to the population dynamics model, it solves the problem of artificially determining the number of individuals. There are 7 operators in the algorithm, they realize the information exchange between individuals the information exchange within and between populations, the information diffusion of strong individuals and the transmission of environmental information are realized to individuals, the number of individuals are increased or decreased to ensure that the algorithm has global convergence. The periodic increase of the number of individuals in the mutant population can greatly increase the probability of the search jumping out of the local optimal solution trap. In the iterative calculation, the algorithm only deals with 3/500∼1/10 of the number of individual features at a time, the time complexity is reduced greatly. In order to assess the scalability, efficiency and robustness of the proposed algorithm, the experiments have been carried out on realistic, synthetic and random benchmarks with different dimensions. The test case shows that the PDO-MCCE algorithm has better performance and is suitable for solving some optimization problems with higher dimensions.

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Career Adaptability and Career Decision Self-Efficacy: Meta-Analysis

Journal of Career Development ◽

10.1177/08948453211012477 ◽

2021 ◽

pp. 089484532110124

Author(s):

Graham B. Stead ◽

Lindsey M. LaVeck ◽

Sandra M. Hurtado Rúa

Keyword(s):

Self Efficacy ◽

Total Population ◽

Meta Analysis ◽

Career Decision ◽

Decision Making Process ◽

Career Adaptability ◽

Efficacy Measures ◽

Meta Analyses ◽

Career Research ◽

The Relationship

The relationship between career adaptability and career decision self-efficacy was examined due to its importance for clients in the career development and career decision-making process. Multivariate meta-analyses using 18 studies with a total population of 6,339 participants were employed. Moderator variables important to this relationship were country of participants, mean age, and career adaptability measures. Estimated correlations between career adaptability subscales and career decision self-efficacy measures ranged from .36 to .44. Findings are discussed in relation to career research and counseling.

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Engine Malfunctioning Conditions Identification through Instantaneous Crankshaft Torque Measurement Analysis

Applied Sciences ◽

10.3390/app11083522 ◽

2021 ◽

Vol 11 (8) ◽

pp. 3522

Author(s):

Konstantinos-Marios Tsitsilonis ◽

Gerasimos Theotokatos

Keyword(s):

Operating Conditions ◽

Cylinder Pressure ◽

Dynamics Model ◽

Engine Model ◽

Measurement Analysis ◽

Start Of Injection ◽

Rate Of Heat Release ◽

Relationship Of ◽

Diagnostic Measurement ◽

The Relationship

In this study a coupled thermodynamics and crankshaft dynamics model of a large two-stroke diesel engine was utilised, to map the relationship of the engine Instantaneous Crankshaft Torque (ICT) with the following frequently occurring malfunctioning conditions: (a) change in Start of Injection (SOI), (b) change in Rate of Heat Release (RHR), (c) change in scavenge air pressure, and (d) blowby. This was performed using frequency analysis on the engine ICT, which was obtained through a series of parametric runs of the coupled engine model, under the various malfunctioning and healthy operating conditions. This process demonstrated that engine ICT can be successfully utilised to identify the distinct effects of malfunctions (c) or (d), as they occur individually in any cylinder. Furthermore by using the same process, malfunctions (a) and (b) can be identified as they occur individually for any cylinder, however there is no distinct effect on the engine ICT among these malfunctions, since their effect on the in-cylinder pressure is similar. As a result, this study demonstrates the usefulness of the engine ICT as a non-intrusive diagnostic measurement, as well as the benefits of malfunctioning conditions mapping, which allows for quick and less resource intensive identification of engine malfunctions.

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SARS-CoV-2 infection is at herd immunity in the majority segment of the population of Qatar

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab221 ◽

2021 ◽

Author(s):

Mohamed H Al-Thani ◽

Elmoubasher Farag ◽

Roberto Bertollini ◽

Hamad Eid Al Romaihi ◽

Sami Abdeen ◽

...

Keyword(s):

Total Population ◽

Herd Immunity ◽

Geographic Location ◽

Population Based ◽

Infection Prevalence ◽

Cross Sectional ◽

Previous Infection ◽

Current Infection ◽

Polymerase Chain ◽

Population Based Survey

Abstract Background Qatar experienced a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic that disproportionately affected the craft and manual worker (CMW) population who comprise 60% of the total population. This study aimed to assess ever and/or current infection prevalence in this population. Methods A cross-sectional population-based survey was conducted during July 26-September 09, 2020 to assess both anti-SARS-CoV-2 positivity through serological testing and current infection positivity through polymerase chain reaction (PCR) testing. Associations with antibody and PCR positivity were identified through regression analyses. Results Study included 2,641 participants, 69.3% of whom were <40 years of age. Anti-SARS-CoV-2 positivity was 55.3% (95% CI: 53.3-57.3%) and was significantly associated with nationality, geographic location, educational attainment, occupation, and previous infection diagnosis. PCR positivity was 11.3% (95% CI: 9.9-12.8%) and was significantly associated with nationality, geographic location, occupation, contact with an infected person, and reporting two or more symptoms. Infection positivity (antibody and/or PCR positive) was 60.6% (95% CI: 58.6-62.5%). The proportion of antibody-positive CMWs that had a prior SARS-CoV-2 diagnosis was 9.3% (95% CI: 7.9-11.0%). Only seven infections were ever severe and one was ever critical—an infection severity rate of 0.5% (95% CI: 0.2-1.0%). Conclusions Six in every 10 CMWs have been infected, suggestive of reaching the herd immunity threshold. Infection severity was low with only one in every 200 infections progressing to be severe or critical. Only one in every 10 infections had been previously diagnosed suggestive of mostly asymptomatic or mild infections.

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Does Revitalizing the Center of Mid-Sized French Cities Reduce GHG Emissions from Commuting?

Sustainability ◽

10.3390/su13041851 ◽

2021 ◽

Vol 13 (4) ◽

pp. 1851

Author(s):

Alexis Poulhès ◽

Angèle Brachet

Keyword(s):

Land Use Planning ◽

Statistical Models ◽

Total Population ◽

Ghg Emissions ◽

Low Carbon ◽

Trip Distance ◽

Working People ◽

Shrinking City ◽

The Relationship ◽

Positive Effect

Mid-sized cities are usually considered in the literature to be shrinking cities. Some policies promote right-sizing and others promote revitalization. The relationship between land-use planning and mobility having been established, the present research issue is focused on whether a policy of revitalizing the centers of mid-sized cities is favorable to low-carbon mobility. Our study investigates commuting trips through two indicators: commuting trip distance and car modal share. The increase in total population, the increase in the number of jobs per resident, the decrease in the unemployment rate, the increase in the rate of executives, the increase in the rate of working people in the population and the decrease in the residential vacancy rate all come from the censuses of 2006 and 2016. Statistical models based on individuals in 113 mid-sized cities, in which sociodemographic variables are introduced, show that at the level of agglomerations, no indicator has a simultaneously positive effect in the center and in the urban periphery. No indicator is entirely positive or negative on GHG emissions from commuting trips. While the increase in GHG emissions from commuting trips between 2006 and 2016 is significant in mid-sized cities (18%), a shift toward shrinking city centers is insufficient to change this trajectory.

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Simulation of Valve Position Feedback Mechanism Based on Pro/E and ADAMS

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.721.244 ◽

2014 ◽

Vol 721 ◽

pp. 244-248

Author(s):

You Jun Fan ◽

Fei Li ◽

Hua Tian Zhao

Keyword(s):

Feedback Mechanism ◽

Dynamics Model ◽

Joint Simulation ◽

Force And Motion ◽

Motion State ◽

Position Feedback ◽

Displacement Angle ◽

Valve Position ◽

Relationship Of ◽

The Relationship

In traditional valve position feedback mechanism design, it is tested repeatedly and improvement after processing prototype, the process is complex and workload. Using Pro/E and ADAMS, the overall mechanical structure of the valve position feedback mechanism for joint simulation, and an analysis of the kinematics and dynamics model, simplified the design process of the repeated calculation, get the relationship of stem displacement-angle between gear, gear meshing force and motion state of the stem, the simulation value compared with the theoretical value, tallies with the data and shows that the simulation is reasonable.

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Daily Sitting for Long Periods Increases the Odds for Subclinical Atheroma Plaques

Journal of Clinical Medicine ◽

10.3390/jcm10061229 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1229

Author(s):

Jose Luis Perez-Lasierra ◽

Martin Laclaustra ◽

Pilar Guallar-Castillón ◽

Jose Antonio Casasnovas ◽

Jose Antonio Casajús ◽

...

Keyword(s):

Physical Activity ◽

Subclinical Atherosclerosis ◽

Sitting Time ◽

Health Study ◽

Activity Levels ◽

Cross Sectional ◽

Trained Personnel ◽

Atherosclerosis Development ◽

Sectional Analysis ◽

The Relationship

Sedentarism is a risk factor for cardiovascular disease (CVD), but currently it is not clear how a sedentary behavior such as long sitting time can affect atherosclerosis development. This study examined the relationship between sitting time and the prevalence of carotid and femoral subclinical atherosclerosis. A cross-sectional analysis based on a subsample of 2082 participants belonging to the Aragon Workers’ Health Study was carried out. Ultrasonography was used to assess the presence of plaques in carotid and femoral territories; the validated Spanish version of the questionnaire on the frequency of engaging in physical activity used in the Nurses’ Health Study and the Health Professionals’ was used to assess physical activity and sitting time; and demographic, anthropometric, and clinical data were obtained by trained personnel during the annual medical examination. Participants were categorized into <9 h/day and ≥9 h/day sitting time groups. After adjusting for several confounders, compared with participants that remain seated <9 h/day, those participants who remain seated ≥9 h/day had, respectively, OR = 1.25 (95%CI: 1.01, 1.55, p < 0.05) and OR = 1.38 (95%CI: 1.09, 1.74, p < 0.05) for carotid and any-territory plaque presence. Remaining seated ≥9 h/day is associated with higher odds for carotid and any-territory plaque presence independently of physical activity levels and other cardiovascular risk factors.

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Maximal Oxygen Uptake and Daily Physical Activity in 7- to 12-Year-Old Boys

Pediatric Exercise Science ◽

10.1123/pes.5.4.357 ◽

1993 ◽

Vol 5 (4) ◽

pp. 357-366 ◽

Cited By ~ 5

Author(s):

Hazzaa M. Al-Hazzaa ◽

Mohammed A. Sulaiman

Keyword(s):

Physical Activity ◽

Heart Rate ◽

Oxygen Uptake ◽

Maximal Oxygen Uptake ◽

Open Circuit ◽

Daily Physical Activity ◽

Activity Level ◽

Activity Levels ◽

School Time ◽

The Relationship

The present study examined the relationship between maximal oxygen uptake (V̇O2max) and daily physical activity in a group of 7- to 12-year-old boys. V̇O2max was assessed through the incremental treadmill test using an open circuit system. Physical activity level was obtained from heart rate telemetry outside of school time for 8 hrs during weekdays and during 40 min of physical education classes. The findings indicated that the absolute value of V̇O2max increased with age, while relative to body weight it remained almost the same across age, with a mean of 48.4 ml · kg−1 · min−1. Moreover, heart rate telemetry showed that the boys spent a limited amount of time on activities that raise the heart rate to a level above 160 bpm (an average of 1.9%). In addition, V̇O2max was found to be significantly related to the percentage of time spent at activity levels at or above a heart rate of 140 bpm, but not with activity levels at or above a heart rate of 160 bpm.

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