scholarly journals Control of Bending-Bending Coupled Vibrations of a Rotating Thin-Walled Composite Beam

2015 ◽  
Vol 39 (4) ◽  
pp. 605-613 ◽  
Author(s):  
Jarosław Latalski ◽  
Marcin Bocheński ◽  
Jerzy Warmiński
Keyword(s):  
Composite Beam ◽  
Dynamic Properties ◽  
Control Strategies ◽  
Fiber Composite ◽  
Bending Moment ◽  
Piezoelectric Actuators ◽  
Transversely Isotropic ◽  
Cross Sectional ◽  
Modal Coupling ◽  
The Impact

Abstract The paper presents a study of a possible application of structure embedded piezoelectric actuators to enhance the performance of a rotating composite beam exhibiting the coupled flexural-flexural vibrations. The discussed transversal and lateral bending modal coupling results from the directional properties of the beam's laminate and ply stacking distribution. The mathematical model of the beam is based on an assumption of cross-sectional non-deformability and it incorporates a number of non-classical effects. The final 1-D governing equations of an active composite beam include both orthotropic properties of the laminate and transversely isotropic properties of piezoelectric layers. The system's control capabilities resulting from embedded Macro Fiber Composite piezoelectric actuators are represented by the boundary bending moment. To enhance the dynamic properties of the composite specimen under consideration a combination of linear proportional control strategies has been used. Comparison studies have been performed, including the impact on modal coupling magnitude and cross-over frequency shift.

scholarly journals The Coronavirus Disease (COVID-19) Pandemic: Simulation-Based Assessment of Outbreak Responses and Post Peak Strategies

2020 ◽  
Author(s):  
Jeroen Struben
Keyword(s):  
Control Strategies ◽  
Critical Role ◽  
Virus Transmission ◽  
Social Contact ◽  
The United States ◽  
Endogenous Virus ◽  
Cross Sectional ◽  
Policy Model ◽  
Policy Interventions ◽  
The Impact

AbstractIt is critical to understand the impact of distinct policy interventions to the ongoing coronavirus disease pandemic. I develop a flexible behavioral, dynamic, and sectorial epidemic policy model comprising both endogenous virus transmission and public health and citizen responses. Applicable to the full epidemic cycle including confinement, deconfinement, and resurgence, the model allows exploring the multivariate impact of distinct policy interventions, including general and targeted testing and social contact reduction efforts. Using a cross-sectional calibration to data on the ongoing coronavirus disease outbreak about reported cases and deaths, tests performed, and social interactions from six countries (South Korea, Germany, Italy, France, Sweden, and the United States), I demonstrate how early, rapid, and extensive buildup of testing and social contact reduction efforts interplay to suppress the outbreak. I then use the model to show and quantify limits to the extent of deconfinement and illustrate the critical role of targeted approaches for managing post peak deconfinement and resurgence. To aid necessary public and expert understanding of outbreak control strategies the model is accessible in the form of a web-based management flight simulator.

scholarly journals High seroprevalence of SARS-CoV-2 antibodies among people living in precarious situations in Ile de France

2020 ◽  
Author(s):  
Thomas Roederer ◽  
Bastien Mollo ◽  
Charline Vincent ◽  
Birgit Nikolay ◽  
Augusto Llosa ◽  
...  
Keyword(s):  
Risk Factors ◽  
Control Strategies ◽  
Food Distribution ◽  
Multivariable Logistic Regression Model ◽  
Cross Sectional ◽  
High Exposure ◽  
Emergency Shelters ◽  
Risk Of Exposure ◽  
Study Sites ◽  
The Impact

AbstractBackgroundA nationwide lockdown was implemented in France on 17 March 2020 to control the COVID-19 pandemic. People living in precarious conditions were relocated by the authorities to emergency shelters, hotels and large venues. Médecins sans Frontières (MSF) then intervened to provide medical care in several of these locations in Paris and in Seine-Saint-Denis, one of its suburbs, between March and June 2020. A seroprevalence survey was conducted to assess the level of exposure to COVID-19 among the population living in the sites. To our knowledge, this is the first assessment of the impact of the pandemic on populations living in insecure conditions in Europe.MethodsWe conducted a cross-sectional seroprevalence study in the food distribution sites, emergency shelters and workers residences supported by MSF in Paris and Seine-Saint-Denis, to determine the extent of COVID-19 exposure as determined by SARS-CoV2 antibody seropositivity. The detection of SARS-COV2 antibodies in serum was performed at the Institut Pasteur of Paris using two LuLISA (Luciferase-Linked Immunosorbent Assay) assays and a Pseudo Neutralization Test. A questionnaire covering sociodemographic characteristics, living conditions, adherence to sanitary recommendations and symptom manifestations was also completed. We describe here the seroprevalence site by site and identify the risk factors for seropositivity using a multivariable logistic regression model with site random effects. We also investigated associations between seropositivity and symptoms eventually reported.FindingsOverall, 426/818 individuals tested positive in the 14 sites investigated. Seroprevalence varied significantly with the type of site (chi2 p<0.001). It was highest at 88.7% (95%CI 81.8-93.2) among individuals living in workers’ residences, followed by 50.5% (95%CI 46.3-54.7) in emergency shelters and 27.8 % (95%CI 20.8-35.7) among individuals recruited from the food distribution sites. Seroprevalence also varied significantly between sites of the same type. Among other risk factors, the odds for seropositivity were higher among individuals living in crowded sites (medium: adj. OR 2.7, 95%CI 1.5-5.1, p=0.001; high: adj. OR 3.4, 95%CI 1.7-6.9, p<0.001) compared with individuals from low crowding sites and among those who reported transit accommodation in a gymnasium before the lockdown (adj. OR 3.1, 95%CI 1.2-8.1, p=0.023). More than two-thirds of the seropositive individuals (68.3%; 95%CI 64.2-72.2) did not report any symptoms during the recall period.InterpretationThe results demonstrate rather high exposure to SARS-COV-2 with important variations between study sites. Living in crowded conditions was identified as the most important explanatory factor for differences in levels of exposure. This study describes the key factors which determine the risk of exposure and illustrates the importance of identifying populations at high risk of exposure in order to orient and adapt prevention and control strategies to their specific needs.

Multidisciplinary team decision is rare and decreasing in percutaneous vascular interventions despite positive impact on in-hospital outcomes

VASA ◽  
2019 ◽  
Vol 48 (3) ◽  
pp. 262-269 ◽  
Author(s):  
Christian-Alexander Behrendt ◽  
Tilo Kölbel ◽  
Thea Schwaneberg ◽  
Holger Diener ◽  
Ralf Hohnhold ◽  
...  
Keyword(s):  
Multidisciplinary Team ◽  
Positive Impact ◽  
Cross Sectional Study ◽  
Invasive Treatment ◽  
Cross Sectional ◽  
Hospital Outcomes ◽  
Vascular Intervention ◽  
Medical Specialties ◽  
Team Decision ◽  
The Impact

Abstract. Background: Worldwide prevalence of peripheral artery disease (PAD) is increasing and peripheral vascular intervention (PVI) has become the primary invasive treatment. There is evidence that multidisciplinary team decision-making (MTD) has an impact on in-hospital outcomes. This study aims to depict practice patterns and time changes regarding MTD of different medical specialties. Methods: This is a retrospective cross-sectional study design. 20,748 invasive, percutaneous PVI of PAD conducted in the metropolitan area of Hamburg (Germany) were consecutively collected between January 2004 and December 2014. Results: MTD prior to PVI was associated with lower odds of early unsuccessful termination of the procedures (Odds Ratio 0.662, p < 0.001). The proportion of MTD decreased over the study period (30.9 % until 2009 vs. 16.6 % from 2010, p < 0.001) while rates of critical limb-threatening ischemia (34.5 % vs. 42.1 %), patients´ age (70 vs. 72 years), PVI below-the-knee (BTK) (13.2 % vs. 22.4 %), and rates of severe TASC C/D lesions BTK (43.2 % vs. 54.2 %) increased (all p < 0.001). Utilization of MTD was different between medical specialties with lowest frequency in procedures performed by internists when compared to other medical specialties (7.1 % vs. 25.7 %, p < 0.001). Conclusions: MTD prior to PVI is associated with technical success of the procedure. Nonetheless, rates of MTD prior to PVI are decreasing during the study period. Future studies should address the impact of multidisciplinary vascular teams on long-term outcomes.

Factors Influencing Academic Stress on Students of University of Economics and Business - Vietnam National University

2020 ◽  
Vol 36 (3) ◽  
Author(s):  
Nham Phong Tuan ◽  
Nguyen Ngoc Quy ◽  
Nguyen Thi Thanh Huyen ◽  
Hong Tra My ◽  
Tran Nhu Phu
Keyword(s):  
Academic Stress ◽  
Stress Factors ◽  
Negative Effects ◽  
Cross Sectional ◽  
Stress Scale ◽  
Perceptions And Attitudes ◽  
National University ◽  
Questionnaire Surveys ◽  
The University ◽  
The Impact

The objective of this study is to investigate the impact of seven factors causing academic stress on students of University of Economics and Business - Vietnam National University: Lack of leisure time, Academic performance, Fear of failure, Academic overload, Finances, Competition between students, Relationships with university faculty. Based on the results of a practical survey of 185 students who are attending any courses at the University of Economics and Business - Vietnam National University, the study assesses the impact of stress factors on students. The thesis focuses on clarifying the concept of "stress" and the stress level of students, while pointing out its negative effects on students. This study includes two cross-sectional questionnaire surveys. The first survey uses a set of 16 questions to assess students’ perceptions and attitudes based on an instrument to measure academic stress - Educational Stress Scale for Adolescents (ESSA). The second survey aims to test internal consistency, the robustness of the previously established 7-factor structure. Henceforth, the model was brought back and used qualitatively, combined with Cronbach’s Alpha measurement test and EFA discovery factor analysis. This study was conducted from October 2019 to December 2019. From these practical analyzes, several proposals were made for the society, the school and the students themselves.

The impact of the use of a footrest on the quality of chest compressions. A prospective, randomized, cross-sectional study

2018 ◽  
Vol 31 (3) ◽  
Author(s):  
Jolanta Majer ◽  
Sandra Pyda ◽  
Jerzy Robert Ladny ◽  
Antonio Rodriguez-Nunez ◽  
Lukasz Szarpak
Keyword(s):  
Cross Sectional Study ◽  
Sectional Study ◽  
Chest Compressions ◽  
Cross Sectional ◽  
The Impact

HIV/AIDS Knowledge and Risk-Taking Behaviours among Youths at a University in Enugu, Nigeria

2018 ◽  
Vol 20 (1) ◽  
Author(s):  
Ada C. Nwaneri ◽  
Okwudili Callistus Ezike ◽  
Agnes N. Anarado ◽  
Ifeoma Ndubisi ◽  
Jane-Lovena Onyia-Pat
Keyword(s):  
Risk Taking ◽  
Control Strategies ◽  
Analysis Of Covariance ◽  
Cross Sectional ◽  
Awareness Campaigns ◽  
South Eastern ◽  
Risky Behaviours ◽  
Aids Knowledge ◽  
The University ◽  
Hiv Aids

 A national sentinel survey of 2006 shows that Enugu State in south-eastern Nigeria is the worst hit by HIV infections. Despite numerous control strategies having been implemented, the state was still reported by another national HIV sentinel survey in 2010 as the worst hit by HIV/AIDS within the zone, and that youths are the most affected. The researchers conducted a cross-sectional descriptive survey to assess the HIV/AIDS knowledge and risk-taking behaviours of youths at a federal university in Enugu, south-eastern Nigeria. They adopted a multistage sampling method to recruit 460 unmarried, consenting students between 15 and 30 years of age, from three faculties of the university. Almost 90 per cent of the university youths had a sound knowledge of key concepts related to HIV/AIDS; despite this, a subset (7.39%) still engaged in risk-taking behaviours. The major risky behaviours identified include having premarital sex, having multiple sexual partners, the sharing of shaving or razor blades, the use of public clippers and tribal marking. Although an analysis of variance demonstrated no significant relationship (t = −0.036) between university youths’ knowledge of HIV/AIDS and their related risk-taking behaviour, risky behaviours were found to be more (13%) among respondents who had insufficient or incorrect knowledge of the disease. An analysis of covariance, however, showed that gender and socio-economic backgrounds were not determinants of the HIV/AIDS risk-taking behaviours of these youths. Therefore, factors such as attitude or culture are areas that should be focused on, and should then, along with educational awareness campaigns, help to reduce the spread and prevalence of the disease.

Awareness of symptomatic differences Covid-19, SARS, Swine Flu, Common cold among dental students

2020 ◽  
Vol 11 (SPL1) ◽  
pp. 1026-1033
Author(s):  
Nivedha Valliammai Mahalingam ◽  
Abilasha R ◽  
Kavitha S
Keyword(s):  
Infectious Diseases ◽  
Undergraduate Students ◽  
Common Cold ◽  
Emerging Infectious Diseases ◽  
Dental Students ◽  
Swine Flu ◽  
Viral Diseases ◽  
Surveillance Systems ◽  
Cross Sectional ◽  
The Impact

Enormous successes have been obtained against the control of major epidemic diseases, such as SARS, MERS, Ebola, Swine Flu in the past. Dynamic interplay of biological, socio-cultural and ecological factors, together with novel aspects of human-animal interphase, pose additional challenges with respect to the emergence of infectious diseases. The important challenges faced in the control and prevention of emerging and re-emerging infectious diseases range from understanding the impact of factors that are necessary for the emergence, to development of strengthened surveillance systems that can mitigate human suffering and death. The aim of the current study is to assess the awareness of symptomatic differences between viral diseases like COVID-19, SARS, Swine flu and common cold among dental students that support the prevention of emergence or re-emergence. Cross-sectional type of study conducted among the undergraduate students comprising 100 Subjects. A questionnaire comprising 15 questions in total were framed, and responses were collected in Google forms in SPSS Software statistical analysis. The study has concluded that dental students have an awareness of the symptomatic differences between infectious viral disease. The study concluded that the awareness of symptomatic differences between viral diseases like COVID-19, SARS, Swine flu, Common cold is good among the dental students who would pave the way for early diagnosis and avoid spreading of such diseases. A further awareness can be created by regular webinars, seminars and brainstorming sessions among these healthcare professionals.

Relationship between Code of Corporate Governance and Corporate Financial Performance (An Empirical Study of Food Companies Listed on KSE)

GIS Business ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. 01-09
Author(s):  
Asma Rafique Chughtai ◽  
Afifa Naseer ◽  
Asma Hassan
Keyword(s):  
Corporate Governance ◽  
Stock Exchange ◽  
Securities And Exchange Commission ◽  
Executive Directors ◽  
Agency Conflicts ◽  
Cross Sectional ◽  
Return On Equity ◽  
Governance Practices ◽  
Code Of Corporate Governance ◽  
The Impact

The crucial role that implementation of Code of Corporate Governance plays on protecting the rights of minorities, shareholders, local as well as foreign investors cannot be denied. Companies all over the world are required to implement their respective Code of Corporate Governance for avoiding agency conflicts between companies management and stakeholders and for assuring transparency in accountability. This paper aims at exploring the impact of implementation of corporate governance practices (designed by Securities and Exchange Commission of Pakistan) have on the financial position of companies. For explanatory variables of the study, composition of the board as per the Code of Corporate Governance that comprises of presence of independent, executive and non-executive directors has been taken into consideration. Return on equity has been taken as an indicator of firms profitability i.e. the dependent variable. For this study, companies listed on food producing sector of Karachi Stock Exchange have been screened for excogitation of the relationship. It is an empirical research based on nine years data from 2007–2015. Using Hausman Test for selecting the data analysis technique between Fixed or Random, Fixed Cross Sectional Panel Analysis has been used for analysis of the data collected. Findings indicate that presence of independent, executive and non-executive directors as per the code requirements levies a significant impact on the profitability of companies indicated by return on equity. It is, thus concluded that companies should ensure compliance with code of governance practices to reduce not only the agency issues but also to increase their profitability.

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